JP7731866B2 - Polymeric articles comprising blends of PBAT, PLA, and carbohydrate-based polymeric materials - Google Patents

Description

CROSS-REFERENCE TO RELATED APPLICATIONS This application claims the benefit of U.S. Patent Application Nos. 62/872,589 (21132.28) and 62/875,872 (21132.28.1), filed July 10, 2019 and July 18, 2019, respectively. This application is also a continuation-in-part of U.S. Patent Application No. 16/425,397 (21132.20.1), filed May 29, 2019, which claims the benefit of U.S. Patent Application No. 62/677,368 (21132.20), filed May 29, 2018. U.S. Patent Application No. 16/425,397 (21132.20.1) is also a continuation-in-part of U.S. Patent Application No. 15/691,588 (21132.7), filed August 30, 2017, which is a continuation-in-part of U.S. Patent Application No. 14/853,725 (21132.8), filed September 14, 2015, which claims the benefit of U.S. Provisional Patent Application No. 62/187,231, filed June 30, 2015. U.S. Patent Application No. 15/691,588 (21132.7) is also a continuation-in-part of U.S. Patent Application No. 14/853,780 (21132.6), filed September 14, 2015, and a continuation-in-part of U.S. Patent Application Nos. 15/481,823 (21132.2) and 15/481,806 (21132.1), both filed April 7, 2017. U.S. Patent Application No. 15/691,588 (21132.7) also claims the benefit of U.S. Provisional Patent Application No. 62/440,399 (21132.10), filed December 29, 2016, and U.S. Provisional Patent Application No. 62/442,432 (21132.11), filed January 4, 2017. The entire contents of each of the foregoing are incorporated herein by reference.

Other applications are also incorporated by reference herein. For example, U.S. Patent Application No. 62/483,219 (21132.4), filed April 7, 2017; U.S. Patent Application No. 15/836,555 (21132.4.1), filed December 8, 2017; U.S. Provisional Patent Application No. 62/483,109 (21132.5), filed April 7, 2017; U.S. Patent Application No. 62/610,615 (21132.9) and U.S. Patent Application No. 16/456,303 (21132.9.1), filed December 27, 2017 and June 28, 2019, respectively; U.S. Patent Application No. 62/610,618 (21132.9), filed December 27, 2017 and June 28, 2019, respectively. Nos. (21132.12) and 16/456,295 (21132.12.1), U.S. Patent Application No. 16/391,909 (21132.14.1), filed April 23, 2019, U.S. Patent Application No. 63/033,676 (21132.31), filed June 2, 2020, PCT Application No. PCT/US2017/068492 (21132.1A), filed December 27, 2017, and two additional non-provisional patent applications of the applicant bearing attorney docket numbers 21132.27.1.1 and 21132.30.1, filed on the same date as the present application, are each incorporated herein by reference in their entirety.

Traditional petrochemical-based plastics are formulated to be strong, lightweight, and durable. However, these plastics are typically not biodegradable, resulting in hundreds of millions of tons of plastic occupying landfills or floating in the oceans. In an effort to reduce the amount of plastic waste, some items typically made using petrochemical-based plastics are being made using bioplastic materials, defined as plastics made from renewable resources or that are biodegradable.

Large amounts of petrochemical-based plastic materials such as polyethylene and polypropylene, as well as many other plastics (e.g., polyethylene terephthalate, polystyrene, ABS, polyvinyl chloride, polycarbonate, nylon, etc.), typically do not readily biodegrade in typical land-based disposal environments (e.g., landfills), or even more so when disposed of in the marine environment. This is typically true even for so-called "green" plastics, where some of such materials may be sourced from renewable or sustainable sources rather than petrochemical feedstocks.

There are several specialized plastic materials that may exhibit some degree of compostability and/or biodegradability under certain disposal conditions. For example, polylactic acid ("PLA") and polybutylene adipate terephthalate ("PBAT") (also known as poly(butylene adipate-co-terephthalate)) have been shown to exhibit some degree of compostability under industrial composting conditions. While such disposal conditions may allow for some biodegradation of PLA or PBAT under some conditions where composting temperatures are elevated (e.g., 58°C), PLA does not exhibit compostability in typical home composting environments, where composting temperatures are significantly lower. In other words, while PBAT may exhibit some biodegradability under such home composting conditions (e.g., 28°C in accordance with EN 13432), PLA does not exhibit any significant biodegradability when disposed of in such environments. Furthermore, PBAT itself is a very flexible material, so flexible that bags made from PBAT may bend significantly under load when filled with items, making it particularly unsuitable for use alone in bags or other film materials. PLA is more rigid, but does not exhibit the desirable characteristics of home compostability.

Providing a film that can address at least some of the problems identified above would be an improvement in the art.

The present disclosure is directed to polymer blends suitable for use as films or rigid materials that meet home compostability requirements (e.g., depending on thickness). The blends include a carbohydrate-based polymer material (e.g., a modified polysaccharide, such as NuPlastiQ®, available from the applicant) blended with PBAT and PLA. NuPlastiQ® and PBAT typically biodegrade in home compost environments, but PLA does not. PLA, even when blended with PBAT alone, similarly does not biodegrade under home compost conditions. However, when NuPlastiQ® is included in the blend, PLA biodegrades under home compost conditions (e.g., at 28°C, otherwise consistent with conditions specified by EN 13432).

Film materials containing PBAT would be desirable for use in applications such as take-out bags, where, unfortunately, significant littering still occurs, even in the United States and other developed countries. The rationale for using PBAT in such articles is that PBAT exhibits biodegradable properties, even under relatively low-temperature home composting conditions, for example. By comparison, the vast majority of such take-out bags (and other film articles) are formed from polyethylene, which essentially exhibits negligible biodegradability under any standardized testing or actual disposal conditions. The problem with using PBAT in such films, for example, is that bags formed from PBAT are extremely elastomeric, to the point that when various items are placed inside the bag, rather than generally maintaining their shape and retaining the items, the bag may actually stretch significantly. Naturally, such properties result in poor overall flexibility and toughness, which is problematic for take-out bags or other film articles, as well as other non-film articles where increased strength and stiffness may be desirable.

Blending PBAT with PLA increases the stiffness of the resulting material, allowing the blend to be used to form films for use as carryout bags or other articles where a good balance of strength, stiffness, flexibility, and toughness is desired. The problem with such PLA addition is that the PLA in such blends does not biodegrade under low-temperature "home" composting conditions (similar to ASTM D-5338, but at 28°C ± 2°C, as specified by EN 13432, for example), resulting in films or other articles that are only partially biodegradable (i.e., the PBAT biodegrades, but the PLA does not).

Applicant has discovered that by adding Applicant's NuPlastiQ® material, not only does the PBAT in the blend biodegrade under such low-temperature home composting conditions, but the PLA, in turn, also biodegrades under such low-temperature conditions. Naturally, because the NuPlastiQ® carbohydrate-based polymer material also biodegrades, all of the polymer materials in such a blend exhibit compostability under low-temperature home composting conditions. Such a result is particularly advantageous.

Additionally, NuPlastiQ® materials are formed from renewable sourced components (e.g., starch and glycerin) and are relatively inexpensive compared to other polymeric materials (e.g., PBAT and PLA) included in the blend. At least some of the components used to produce PBAT (e.g., butanediol, adipic acid, terephthalic acid) or PLA (e.g., lactic acid) may also be formed from renewable sourced components.

PBAT, which exhibits low stiffness, high flexibility, and/or high toughness (and low strength), can benefit from blending with materials such as PLA to increase stiffness, and if a carbohydrate- or starch-based polymer material such as NuPlastiQ® is also included in the blend, ensuring that all polymer materials in the blend are compostable. In one embodiment, the blend of the present invention comprises a first polyester plastic material (e.g., comprising PBAT) having a first stiffness and a second polyester (e.g., comprising PLA), where the first polyester plastic material has a stiffness lower than (and/or greater flexibility than) that of the second polyester (e.g., PLA). The blend also includes a carbohydrate-based polymer material.

An exemplary embodiment may include PBAT in an amount of at least 30% by weight of the blend, PLA in an amount of up to 20% by weight of the blend, and a carbohydrate-based polymer material in an amount of up to 60% by weight of the blend, e.g., 5% to 60% by weight, or 10% to 60% by weight. By way of example, the carbohydrate-based polymer material may more typically be included in an amount of 30% to 60% by weight of the polymer blend. PLA may be present in an amount of up to 15% or up to 12% by weight of the polymer blend, with PBAT comprising the remainder of the polymer content (e.g., 30-70% by weight). In one embodiment, PLA may be present in an amount of at least 10% by weight of the blend, or greater than 10% by weight. In addition to the polymer components, inorganic fillers such as calcium carbonate, talc, etc. may also be included. The inclusion of such filler materials can further reduce the amount of polymeric components required to manufacture a particular bag, other film, or other article, and can also help reduce any tendency of bags formed from such films to exhibit "blocking" or clumping, which can result in the sides of such bags tending to stick to one another, making the bag somewhat difficult to actually open. In one embodiment, such inorganic fillers can be included in an amount of, for example, 0% to 30% by weight of the article.

Any of a variety of other additives may also be included, if desired, including, but not limited to, for example, slip aids and/or processing aids.
Such composite plastic blends can be processed according to a wide variety of known manufacturing methods to form extruded plastic products, injection molded plastic products, blow molded plastic products, blown film plastic products, extruded or cast sheet or film, thermoformed plastic products, foamed plastic products, and the like.

Further features and advantages of the present invention will become apparent to those skilled in the art upon consideration of the following detailed description of the preferred embodiments.

So that the above and other advantages of the invention are obtained, a more particular description of the invention, briefly described above, will be rendered by reference to specific embodiments thereof which are illustrated in the accompanying drawings. The invention will be described and explained with additional specificity and detail through the use of the accompanying drawings, with the understanding that these drawings illustrate only typical embodiments of the invention and therefore should not be considered as limiting its scope.
1 shows a flow diagram of an exemplary process for forming an article according to the present invention. 2 illustrates components of an exemplary manufacturing system for producing an article according to FIG. 1. The X-ray diffraction (XRD) pattern of NuPlastiQ® GP, a commercially available carbohydrate-based polymer material from BioLogiQ, is shown in comparison to the XRD patterns of the native corn starch and native potato starch used to form NuPlastiQ® GP. The significant reduction in crystallinity is readily apparent. 1 shows dart drop impact strength data for exemplary blends of NuPlastiQ® with PBAT and PLA. Figure 1 shows FT-IR spectral data for NuPlastiQ® GP, as well as native corn starch and native potato starch. Starch is hydrophilic, while NuPlastiQ® GP is hydrophobic. Photographs showing the relative hydrophobic properties of a film comprising NuPlastiQ® blended with another polymer material compared to another film comprising conventional starch blended with another polymer material, illustrating how NuPlastiQ® is much more hydrophobic when tested with a dyne pen at a given weight fraction of starch-based component relative to the same polyolefin matrix material. 1 shows DSC melting temperature profile data for conventional starch materials. 1 shows TGA temperature stability data for exemplary NuPlastiQ® materials compared to glycerin and starch. [0023] Figure 1 shows the biodegradation rates measured over 179 days in accordance with EN 13432 at home compost conditions intended to mimic home compost conditions at ambient temperature (28°C) for various samples made in accordance with the present disclosure, as described in Example 1, and a positive control. [0033] Figure 1 shows the results of disintegration testing from initiation to 26 weeks based on the ISO 20200 standard, which is intended to mimic compost conditions at ambient temperature (28°C), for sample BC27240 made in accordance with the present disclosure, as described in Example 2. 1 shows photographs of test samples BC27130 and BC27251 at the start of the study, as described in Example 3. 1 shows a photographic comparison of test sample BC27130 at the start of the study and after 4 weeks, as described in Example 3. 1 shows a photographic comparison of test sample BC27251 at the start of the study and after 4 weeks, as described in Example 3. 1 shows a photograph of the contents of a composting reactor containing test sample BC27130 after 8 weeks, as described in Example 3. 1 shows a photograph of the contents of a composting reactor containing test sample BC27251 after 8 weeks, as described in Example 3. 1 shows a photographic comparison of test sample BC27130 at the start of the study and after 12 weeks, as described in Example 3. 1 shows a photographic comparison of test sample BC27251 at the start of the study and after 12 weeks, as described in Example 3. 1 shows a photograph of the contents of a composting reactor containing test sample BC27130 after 14 weeks, as described in Example 3. 1 shows a photograph of the contents of a composting reactor containing test sample BC27251 after 14 weeks, as described in Example 3.

I. Definitions All publications, patents, and patent applications cited herein, whether supra or infra, are herein incorporated by reference in their entirety to the same extent as if each individual publication, patent, or patent application was specifically and individually indicated to be incorporated by reference.

The term "comprising," which is synonymous with "including," "containing," or "characterized by," is inclusive or open-ended and does not exclude additional, unrecited elements or method steps.

The term "consisting essentially of" limits the scope of a claim to the particular materials or steps of the claimed invention and "do not materially affect the basic and novel characteristics."

As used herein, the term "consisting of" excludes any element, step, or ingredient not specified in the claim.
As used in the context of describing features of the present invention (particularly in the context of the claims that follow), the terms "a,""an,""the," and similar referents should be construed to encompass both the singular and the plural, unless otherwise specified herein or clearly contradicted by context. Thus, for example, reference to "starch" may include one, two, or more starches.

As used herein, "film" refers to a thin, continuous article comprising one or more polymeric materials that can be used to separate areas or volumes, hold items, act as a barrier, and/or serve as a printable surface.

As used herein, "bag" refers to a container made of relatively thin, flexible film that can be used to contain and/or transport goods.
As used herein, "bottle" refers to a container that can be made from the presently disclosed plastic, which is typically thicker than a film and typically includes a relatively narrow neck adjacent to an opening. Such bottles can be used to hold a wide variety of products, such as beverages, personal care products such as shampoos, conditioners, lotions, soaps, detergents, etc.

All percentages, ratios, parts, and amounts used and described herein are by weight unless otherwise specified. Molecular weight values refer to weight average molecular weight unless otherwise specified.

As will be understood by those skilled in the art, numbers, percentages, ratios, or other values described herein may include that and other values that are about or approximately the stated value. Accordingly, a stated value should be interpreted broadly enough to encompass values at least sufficiently close to the stated value and/or values that round to the stated value to perform the desired function or achieve the desired result. The stated value includes at least expected variation in a typical manufacturing process and may include values within 25%, 15%, 10%, 5%, 1%, etc., of the stated value. Furthermore, as used herein, the terms "substantially," "similarly," "about," or "approximately" refer to an amount or condition that is close to the stated amount or condition that still performs the desired function or achieves the desired result. For example, the terms "substantially," "about," or "approximately" may refer to an amount that is within 25%, 15%, 10%, 5%, or 1% of the stated amount.

Several ranges are disclosed herein. Additional ranges may be defined between any of the values disclosed herein as examples of particular parameters. All such ranges are contemplated and are within the scope of the present disclosure. Furthermore, the recitation of ranges of values herein is intended to serve as a shorthand method of individually referring to each individual value falling within the range. Unless otherwise stated herein, each individual value is incorporated herein as if set forth individually herein.

All numbers expressing quantities of ingredients, components, conditions, and the like used in the specification and claims should be understood as being modified in all instances by the term "about." Notwithstanding that the numerical ranges and parameters setting forth the broad scope of the invention are approximations, the numerical values set forth in the specific examples are reported as precisely as possible. However, any numerical value inherently contains certain errors necessarily resulting from the standard deviation found in their respective testing measurements.

As used herein, the phrase "free of" or similar phrases means that the composition contains 0% of the stated component, i.e., the component has not been intentionally added to the composition. However, it will be understood that such components may form incidentally under appropriate circumstances and may be accidentally present in another included component, for example, as an incidental contaminant.

As used herein, the phrase "substantially free" or similar phrases means that the composition preferably contains 0% of the listed component, although it is understood that very low concentrations may be present, for example, due to accidental formation, accidental contamination, or even intentional addition. Such components, if present at all, may be present in amounts of less than 1%, less than 0.5%, less than 0.25%, less than 0.1%, less than 0.05%, less than 0.01%, less than 0.005%, or less than 0.001%. In one embodiment, the disclosed compositions may be free of any component not specifically disclosed as being contained therein.

The term "non-biodegradable," as used herein with respect to a material, means that a natural material (without additives added to render it biodegradable) does not break down (particularly biodegrade) to a significant extent, e.g., into carbon dioxide and/or methane, within a reasonable time limit (e.g., 1 year, 3 years, or 5 years) when exposed to various simulated disposal conditions (e.g., EN 13432, ASTM D-5338, ASTM D-5511, and/or ASTM D-6691). As described herein, home compostability standards based on EN 13432 may be similar to those based on ASTM D-5338, but are performed at lower temperatures. In a similar manner, any other such standards may be modified (e.g., performed at lower temperatures) to assess biodegradability under more stringent conditions (e.g., home compostability vs. industrial compostability). It should be further understood that given sufficient time and exposure to the conditions of sunlight, oxygen, and degrading microorganisms, most polymeric materials (e.g., even those typically considered "non-biodegradable") will eventually degrade or even biodegrade, usually to some limited extent, over an extended period of time (e.g., decades or centuries).

The term "biodegradable" as used herein with respect to a material means that the material, including NuPlastiQ®, described herein, biodegrades into basic elements such as carbon dioxide, methane, and/or water under conditions as described herein. Typical home compostability standards require at least 90% biodegradation of an item's polymer content within 365 days (i.e., reaching 90% biodegradation when measured according to EN 13432 at 28°C (±2°C) but not at higher temperatures). Similar standards may also be applicable under other certification bodies or regulatory authorities, e.g., biodegradability and/or disintegration standards under ISO 20200, or various similar standards for home compostability (e.g., NF T51-800 (2015), AS 5810 (2010), or TUV Austria Belgium's OK Compost Home certification scheme).

With respect to various standardized tests (e.g., ASTM or other tests), it will be understood that any reference to such standards refers to the most recent update (if any) of such standards.

The term "modified," when used to describe modified polysaccharides, e.g., "modified starch," refers to physical and/or chemical modifications, including converting the starting starch material to one containing a lower molecular weight. Such mechanical and/or chemical modifications may include mechanical modification of the amylopectin starch component to a more linear amylose structure. It will be understood that the foregoing description is merely exemplary, and that many modifications to such starch components are possible. Applicant's NuPlastiQ® material is one example of a modified starch.

While the NuPlastiQ® starch-based polymer described herein is one example of a starch-based material that can provide the benefits described herein, it will be understood that the scope of the present invention extends broadly to other starches or starch-based materials (e.g., developed sometime in the future) that may exhibit similar small particle size characteristics, or even materials that may be synthesized from starting materials other than starch, that may achieve similar results due to the presence of the same or similar chemical structure or functional groups. For example, a material having a similar or identical chemical structure to NuPlastiQ®, synthesized (e.g., in a reactor) starting from a non-starch material, would also be within the scope of the present invention.

II. Introduction The present disclosure is directed to, among other things, blends of two polyester materials, such as PBAT and PLA, with a carbohydrate-based (e.g., starch-based) polymeric material, which enhance the biodegradability of the PLA material within the blend. For example, while PBAT is recognized as readily biodegradable even under relatively low, ambient temperature composting conditions (e.g., "home composting conditions" as opposed to "industrial composting conditions"), PLA does not exhibit such properties and is not compostable under such relatively low, ambient temperature composting conditions, even when blended with PBAT. For example, in such blends, the PBAT biodegrades while the PLA remains largely in its initial form, and therefore, such blends do not meet home composting standards, such as the biodegradability and/or disintegration standards under ISO 20200, or various similar standards for home compostability (e.g., NF T51-800 (2015), AS 5810 (2010), or the OK Compost Home certification scheme of TUV Austria Belgium). Applicant has discovered that while PLA does not biodegrade under such conditions by itself, by homogeneously blending PLA with certain carbohydrate-based (e.g., starch-based) polymeric materials available from Applicant, the biodegradability of PLA can be increased (e.g., in rate and/or extent), such that the overall blend in turn does indeed meet the applicable home compostability standards.

Further explanation of the requirements necessary to meet the "home compostability" criteria is provided below. To meet the applicable criteria, a material must: (1) pass the heavy metal criteria (i.e., none of the constituent materials of the blend (e.g., PBAT, PLA, or carbohydrate-based polymeric materials) contain any prohibited heavy metals; (2) meet the applicable biodegradation criteria, such that at least 90% of the blend biodegrades (as determined by applicable respirometry testing) under such home composting conditions (e.g., 28°C ± 2°C) within 365 days); (3) meet the applicable disintegration criteria (e.g., at least 90% of the tested material reduces in size to less than 2 mm at ambient temperature (e.g., 28°C ± 2°C) within 26 weeks); and (4) meet the applicable ecotoxicity criteria (i.e., each constituent material of the blend (e.g., PBAT, PLA, and carbohydrate-based polymeric materials) meets such ecotoxicity criteria).

The blends of the present invention meet such criteria and provide a viable alternative to polyethylene bags or other films that are not biodegradable to any significant degree, while addressing the softness, extreme flexibility, and lack of sufficient rigidity of bags or other films formed entirely from PBAT, or the limited biodegradability of bags formed from PBAT/PLA blends. Thus, the blends of the present invention can be used to form bags that provide good performance characteristics (e.g., a good balance of strength, rigidity, flexibility, etc.) while ensuring that each of the above home compostability criteria is met. Because contemplated carbohydrate-based polymer materials (e.g., NuPlastiQ®, available from the applicant) are generally cost-competitive with polyethylene (i.e., less expensive than PBAT and PLA), blends and bags or other films formed therefrom can also be manufactured more cost-competitively than if the bags were formed solely from PBAT and/or PLA.

Such blends are particularly beneficial in that they offer a viable alternative to the manufacture of many plastic products and allow such materials to advantageously biodegrade under home composting conditions within a reasonable time frame, rather than existing indefinitely in the stable state of plastic.

Furthermore, Applicant has observed that, like paper, biodegradation of such articles does not readily occur when the articles are stored in typical storage and use environments (e.g., stored in a home, office, warehouse, etc.), but generally begins to occur only when the articles are placed in or exposed to an environment that mimics an aerobic or anaerobic digester, such as the conditions provided by the relevant ASTM or other biodegradability testing standards described herein. For example, such conditions often include (i) temperatures that may be at least somewhat higher than normal "use" or "storage" temperatures, (ii) exposure to high humidity levels, and (iii) exposure to specific classes of microorganisms that are lacking in composting or similar waste environments. While elevated temperature and humidity may cause degradation, they will not cause biodegradation of such articles unless the necessary microorganisms are also simultaneously present. Such a combination of conditions will cause articles formed from such material blends to begin biodegrading. Third-party testing, such as that described herein, confirms that not only do carbohydrate-based polymeric materials and PBAT biodegrade under home composting conditions, but that PLA also biodegrades under such moderate conditions (PLA is otherwise resistant to biodegradation under lower temperature (i.e., 28°C) home composting conditions).

While the mechanism by which blending with carbohydrate-based polymer materials enables such biodegradation of PLA may not be fully understood, it is likely that blending the two polyester plastic materials with a high degree of homogeneity, and perhaps coupling with specific properties of the carbohydrate-based polymer material, somehow overcomes the moisture-wicking barrier associated with PLA, allowing microorganisms that biodegrade the carbohydrate-based polymer material to not only biodegrade the carbohydrate-based polymer material but also the adjacent polyester-linked PLA monomer units. Carbon and other bonds are broken, and biodegradation is confirmed based on third-party testing (i.e., respirometry-based testing) that captures and measures degassed carbon dioxide and methane. Such results are particularly advantageous. U.S. Patent Application Nos. 62,872,582 (21132.27) and 62/939,460 (21132.27.1), filed July 10, 2019 and November 22, 2019, respectively, which are incorporated by reference in their entireties, contain further description related to the uniformly blended small particle starch properties of such blends.

Previous literature in this field has shown that PLA exhibits biodegradation under industrial composting conditions (e.g., ASTM D-5338) where temperatures are significantly higher (e.g., 58°C vs. 28°C), but is notably resistant to biodegradation under home composting conditions at ambient temperatures.

It would clearly be advantageous to find a way to increase the rate and/or extent of biodegradability of PLA materials within a reasonable time frame (e.g., 365 days as applicable under various standardized certification criteria) when disposed of in a home composting environment. For example, the blends of the present invention may include blends of PBAT and PLA in combination with a carbohydrate-based polymeric material, thereby achieving improved physical properties while simultaneously providing full home compostability for the resulting bag, film, or other article.

Plastic articles can be produced by blending a carbohydrate-based polymer material with two polyester plastic materials, heating the mixture, molding the mixture (e.g., injection molding), extruding the mixture, blow molding the mixture, blow molding the mixture (e.g., forming a blown film), thermoforming the mixture, etc. Various other plastic manufacturing processes will be apparent to those skilled in the art in light of this disclosure, Applicant's other applications, and general knowledge in the art. Thermosetting materials can also be blended (e.g., such blending processes may or may not require heating).

The articles described herein can be manufactured in the form of any conceivable structure, including, but not limited to, bags, other films, and bottles, boxes, other containers, sheets, etc. Thin films for bags and film wraps (e.g., for wrapping around or over products) can be readily made using blown film equipment.

Examples of suitable carbohydrate- or starch-based polymeric materials that have been shown to render or enhance the biodegradability of polyester plastic materials that exhibit limited or no biodegradability are available from BiologiQ under the trade name NuPlastiQ®. Specific examples include, but are not limited to, NuPlastiQ® GP and NuPlastiQ® CG. The specific properties of such NuPlastiQ® materials are described in further detail herein. Other carbohydrate- or starch-based polymeric materials may also be capable of enhancing the biodegradability of PLA materials included in the blend and may be suitable for use, provided they are specifically selected for this purpose. To select such a material for this purpose, its ability to render or enhance the biodegradability of PLA must be recognized. Applicant is not currently aware of any such materials, other than NuPlastiQ®, that have been shown to function in this manner.

Applicant also offers masterbatch blends of NuPlastiQ® and conventional polymeric materials under the trade name BioBlend, including, but not limited to, BioBlend XP, BioBlend XD, BioBlend MB, BioBlend BC, and BioBlend CB. Such masterbatches may contain higher percentages of modified polysaccharide (NuPlastiQ®), which can be down-blended with other polymeric materials before forming the final product.

III. Exemplary Articles and Methods Figure 1 illustrates an exemplary process 100 that can be used in accordance with the present invention. At 102, process 100 can include providing two or more polyester plastic (e.g., polymer) materials, such as PBAT and PLA, among others. While PBAT already exhibits home compostability, PLA does not. Blending with a carbohydrate-based polymer material as described herein can impart home biodegradability to the overall blend (by enhancing the biodegradability of the PLA material). The presence of a carbohydrate-based polymer material as described herein intimately dispersed with the polyester material can also enhance the biodegradability (e.g., rate and/or extent) of PBAT or other polyester materials included in the blend. At 104, process 100 can include providing one or more carbohydrate-based polymer materials (e.g., NuPlastiQ®). While other materials may be suitable for use, in one embodiment, the selected carbohydrate-based polymer material may be specifically selected for blending with polyester due to its recognized ability to enhance the biodegradability of at least one of the polyester plastic materials (e.g., PLA) provided in 102. One or more carbohydrate-based polymer materials may include a starch-based polymer material, although typical, conventionally available carbohydrate-based polymer materials do not necessarily result in a blend that meets home compostability requirements. Applicant's NuPlastiQ® material is an example of a specific carbohydrate-based polymer material that functions as described herein. NuPlastiQ® is particularly suitable because it can be incorporated while maintaining other desired physical properties, such as desired strength characteristics (e.g., particularly dart drop impact strength). The carbohydrate-based polymer material and polyester plastic material may be provided in a desired form, such as pellets, powder, nurdles, slurries, and/or liquids. In one embodiment, the materials may be in the form of pellets. The method further includes blending the polyester plastic material with the carbohydrate-based polymer material.

Surprisingly, Applicant has observed that such blending results in an overall blend that is home compostable, even though PLA itself (whether alone or blended with PBAT) would not normally meet such criteria. This is believed to be due, at least in part, to the uniform blending of the NuPlastiQ® material into the polyester component. In any event, such blends of materials meet applicable home compostability criteria tests, as evidenced by third-party testing included in the Examples section of this application.

Such blends can be formed into desired articles during manufacturing through any conceivable process. One such example would be an extrusion process. For example, a polyester plastic material (e.g., PBAT and PLA) and a carbohydrate-based polymer material can be fed into an extruder (e.g., into one or more hoppers thereof). The different materials can be fed into the extruder in the same chamber, in different chambers, at approximately the same time (e.g., via the same hopper), or at different times (e.g., via different hoppers, one introduced into the extruder earlier along the screw than the other), etc. It will be apparent that a great many configurations are possible.

The two polyester materials (e.g., PBAT and PLA) can be sourced from petrochemical sources or so-called "green" or sustainable sources (e.g., corn used to produce lactic acid, corn used to form PLA, etc.). Those skilled in the art will recognize that renewable or sustainable feedstocks refer to plant sources that are renewable within less than 100 years, for example, rather than petrochemical feedstocks. Those skilled in the art will also understand that there are various tests to confirm the sustainable or renewable content of plastics or other materials, for example, due to the higher ^C14 to ^C12 ratio in renewable materials that contain carbon compared to materials sourced from fossil fuels.

The carbohydrate-based polymeric material can be formed from multiple ingredients (e.g., a mixture) including one or more starches. For example, the one or more starches can be derived from one or more plants, such as corn starch, tapioca starch, cassava starch, wheat starch, potato starch, rice starch, sorghum starch, etc. In some embodiments, a mixture of different types of starches can be used, which can provide a synergistic increase in strength, as described, for example, in applicant's U.S. Patent No. 10,214,634 and U.S. Patent Application No. 16/287,884, filed February 27, 2019 (each of which is incorporated herein by reference in its entirety). A plasticizer is also present in the mixture of ingredients from which the carbohydrate-based polymeric material is formed. Water can also be used in forming the carbohydrate-based polymeric material (e.g., initially as a plasticizer), but only small to negligible amounts of water are present in the finished carbohydrate-based polymeric material.

One or more carbohydrate-based polymer materials may be formed predominantly from starch. For example, at least 65%, at least 70%, at least 75%, or at least 80% by weight of the carbohydrate-based polymer material may be attributable to one or more starches. In one embodiment, 65% to 90% by weight of the finished carbohydrate-based polymer material may be attributable to one or more starches. Other than negligible water content, the remainder of the finished carbohydrate-based polymer material may be attributable to plasticizers (e.g., glycerin). The finished carbohydrate-based polymer material, such as that exemplified by NuPlastiQ®, is not simply a mixture of starch and glycerin, as described below in connection with Figure 3. Nevertheless, the NuPlastiQ® material is derived from a mixture of these materials.

The above percentages may represent the percentage of starch relative to the starting material from which the carbohydrate-based polymer material is formed, or the percentage of the finished carbohydrate-based polymer material that is derived or attributable to starch (e.g., at least 65% of the carbohydrate-based polymer material may be attributable to (formed from) starch as a starting material). While some water may be used in forming the carbohydrate-based polymer material, substantially the remainder of the carbohydrate-based polymer material may be attributable to glycerin or another plasticizer. Very little residual water (e.g., less than 2%, typically about 1% or less (e.g., 0.1-1.5%)) may be present in the finished carbohydrate-based polymer material.

For example, the material from which one or more carbohydrate-based polymer materials are formed can include at least 12% by weight, at least 15% by weight, at least 18% by weight, at least 20% by weight, at least 22% by weight, no more than 35% by weight, no more than 32% by weight, no more than 30% by weight, no more than 28% by weight, or no more than 25% by weight of plasticizer. Such percentages can represent the proportion of the finished carbohydrate-based polymer material that originates or is attributable to the plasticizer (e.g., at least 12% of the carbohydrate-based polymer material can be attributable to (formed from) the plasticizer as a starting material). Such percentages can also represent the proportion of the mixture of materials from which the finished carbohydrate-based polymer material is formed, excluding any water initially present. Of course, it may be possible for carbohydrate-based polymer materials to be produced with less than 12% (e.g., less than 12%, perhaps even 0%) of plasticizer.

Exemplary plasticizers include glycerin, polyethylene glycol, sorbitol, polyhydric alcohol plasticizers, non-hydroxyl hydrogen bond-forming organic compounds, anhydrides of sugar alcohols, animal proteins, vegetable proteins, fatty acids, phthalates, dimethyl and diethyl succinates and related esters, glycerol triacetate, glycerol monoacetate and diacetate, glycerol mono-, di-, and tripropionate, butanoates, tearate, lactates, citrates, adipates, stearates, oleates, other acid esters, or combinations thereof. Glycerin may be preferred.

The finished carbohydrate-based polymer material may contain 5% or less, 4% or less, 3% or less, 2% or less, 1.5% or less, 1.4% or less, 1.3% or less, 1.2% or less, 1.1% or less, or 1% or less by weight of water. NuPlastiQ® material available from BiologiQ is an example of such a finished carbohydrate-based polymer material, but it should be understood that other materials available elsewhere (e.g., at some point in the future) may also be suitable for use.

In some embodiments, a mixture of different starches may be used in forming the carbohydrate-based polymer material. In such a mixture of starches, the starch may be present in the mixture in an amount of at least 1%, at least 2%, at least 3%, at least 4%, at least 5%, at least 10%, at least 15%, at least 20%, at least 25%, at least 30%, at least 35%, at least 40%, up to 95%, up to 90%, up to 85%, up to 80%, up to 75%, up to 70%, up to 65%, up to 60%, up to 55%, up to 50%, or between 10% and 50% by weight, based on the total weight of the starches. Some non-limiting exemplary mixtures may include 90% first starch and 10% second starch, or 30% first starch and 70% second starch, or 50% first starch and 50% second starch. Mixtures of more than two starches (e.g., using three or four different starches) can also be used.

Examples of carbohydrate-based (e.g., starch-based) polymeric materials suitable for use in forming films and other articles are available from BioLogiQ, located in Idaho Falls, Idaho, under the trade name NuPlastiQ®. Specific examples include, but are not limited to, NuPlastiQ® GP and NuPlastiQ® CG. NuPlastiQ® may also be provided in pellet form. The physical properties of two examples of NuPlastiQ® materials, formerly known as GS-270 and GS-300, are shown in Table 1 below.

As previously mentioned, the above basic properties shown for GS-270 and GS-300 are exemplary of the new NuPlastiQ® products available from BioLogiQ, although values may vary somewhat. For example, suitable NuPlastiQ® products may generally have glass transition temperatures ranging from about 70°C to about 100°C. Those skilled in the art will appreciate that glass transition temperatures can be an indicator of crystallinity. Values for melting temperature range, density, Young's modulus, and water content are similar to those shown in Table 1 above. Some properties may also vary somewhat (e.g., ±25%, or ±10%) from the values shown in Table 1. NuPlastiQ® has an amorphous structure (e.g., more amorphous than typical raw starch). For example, as described in more detail in connection with Figure 3 below, typical raw starch powders have a mostly crystalline structure (e.g., greater than 50%), while NuPlastiQ® has a mostly amorphous structure (e.g., less than 10% crystals).

While some properties may be similar to other thermoplastic starch materials, other properties may be quite different from typical starch-based materials. For example, the density of such reactively extruded NuPlastiQ® materials is particularly high, e.g., greater than 1 g/cm ³ , at least 1.1 g/cm ³ , at least 1.2 g/cm ³ , or at least 1.25 g/cm ³ (e.g., 1.4 g/cm ³ as shown in Table 1 above). Various other properties may also differ substantially from superficially similar starch-based polymer materials.

As described, NuPlastiQ® material has a low moisture content. As the material absorbs moisture, it exhibits plastic behavior and becomes flexible. When removed from the humid environment, the material dries and becomes rigid again (e.g., again exhibiting a moisture content of less than about 1%). Moisture present in NuPlastiQ® (e.g., in pellet form) can be released in the form of vapor during processing (e.g., extrusion, blown film, injection molding, blow molding, etc.). As a result, films or other articles made from starch-based polymer materials blended with another plastic material may exhibit even lower moisture content, and the PBAT, PLA, or other polyester materials used may exhibit negligible moisture content; any water in NuPlastiQ® may typically be released during the manufacture of the desired article.

The low water content of carbohydrate-based NuPlastiQ® polymer materials, and NuPlastiQ®'s hydrophobic rather than hydrophilic properties, can be important because significant water content (or hydrophilicity) can result in incompatibility with the polyester materials (typically considered hydrophobic, at least in the case of PBAT and PLA) with which the NuPlastiQ® material is blended. Water content is particularly problematic when the article requires the formation of a thin film. For example, evaporation of water can result in voids within the film or other article, as well as other problems. When blown into thin films, the carbohydrate-based polymer materials used may preferably contain no more than about 1% water. By matching the hydrophobicity between the NuPlastiQ® material and the polyester polymer material with which it is blended, this can also help achieve a uniform distribution of very small particle sizes of the NuPlastiQ® material dispersed within the polyester material, as described in Applicant's Patent Application No. 62/872,582 (21132.27), filed July 10, 2019, which is incorporated herein by reference in its entirety.

The low water content in NuPlastiQ® materials is not achieved by esterification, as is common in some conventional TPS materials that may contain relatively low water contents. Such esterification can be expensive and complicated to implement. Furthermore, NuPlastiQ® materials, which are exemplary carbohydrate-based polymer materials employable herein, have been mechanically, physically, or chemically reacted and/or altered compared to the starting starch and glycerin materials. X-ray diffraction patterns of exemplary carbohydrate-based polymer materials described below (e.g., shown in Figure 3) demonstrate such chemical or physical changes. Furthermore, while both the starch and glycerin starting materials are hydrophilic, NuPlastiQ® materials are hydrophobic. In other words, carbohydrate-based polymer materials are not recognized as simple mixtures containing natural starch and glycerin. The low water content achievable in carbohydrate-based polymeric materials, and the hydrophobicity exhibited, may be due, at least in part, to the physical or chemical transformation of the starch and plasticizer materials into hydrophobic thermoplastic polymers that do not retain water like native starches, or conventional thermoplastic starches.

Nevertheless, processing at relatively high temperatures may result in the release of some volatilized glycerin (e.g., visible as smoke). If necessary (e.g., if stored pellets may have absorbed additional water), drying of the pellets can be accomplished by simply introducing warm, dry air, e.g., at 60°C, for 1-4 hours, which is sufficient to drive off any absorbed water. Pellets should be dried to a moisture content of less than about 1% before processing, particularly if they are to be formed into a film. NuPlastiQ® pellets can simply be stored in a sealed container, with or without a desiccant, in a dry place away from heat to minimize water absorption and prevent unwanted decomposition.

In addition to being thermoplastic, NuPlastiQ® can also be thixotropic, meaning that the material is solid at ambient temperature but flows as a liquid when heat, pressure, and/or frictional movement are applied. Advantageously, NuPlastiQ® pellets can be used in standard plastic manufacturing processes in the same way as petrochemical pellets (any typical plastic resin pellets). NuPlastiQ® materials and products made therefrom can exhibit gas barrier properties. Products (e.g., films) made using such pellets exhibit oxygen gas barrier properties. NuPlastiQ® materials can be non-toxic and edible, and can be made using all edible raw materials. NuPlastiQ® and products made therefrom can be water-resistant, even hydrophobic, but also water-soluble. For example, NuPlastiQ® may not completely dissolve in boiling water within 5 minutes, but may resist swelling under moist heat conditions to the extent that pellets (e.g., 3-4 mm in size) dissolve in the mouth within about 10 minutes. That said, films containing NuPlastiQ® may still have a relatively low surface wettability (e.g., 40 mN/m (40 dynes/cm) or less), lower than that of conventional blends of TPS materials, as well as PBAT, PLA, or other polyester materials with which it is blended.

NuPlastiQ® materials also generally do not disintegrate or biodegrade under typical storage conditions, even in relatively humid conditions, due to the absence of other conditions typical of landfills, compost, or similar waste environments. Naturally, when such conditions exist, not only will NuPlastiQ® biodegrade, but PLA will also exhibit enhanced biodegradability to meet standards for home compostability.

NuPlastiQ® can be cost-competitive because it is manufactured at a cost competitive with conventional polyethylene or other inexpensive plastic resins. This is advantageous because polyester resins such as PBAT and PLA are significantly more expensive than polyethylene. The inclusion of NuPlastiQ® in the blends of the present invention allows them to be relatively less expensive than they would otherwise be. More specifically, PBAT can typically be about three times more expensive than polyethylene. Because NuPlastiQ® is cost-competitive with polyethylene, the blends of the present invention can actually be offered at a lower cost than conventional 100% PBAT film (or PBAT/PLA blends) or other articles. In addition to a potentially improved cost structure, the blends of the present invention also offer the advantage of a significant portion of the blended article being sourced from sustainable feedstocks (e.g., starch) that would otherwise often be considered waste.

As a further explanation, PLA is industrially compostable, i.e., capable of decomposing under high-temperature conditions (i.e., industrial composting conditions, i.e., 58°C), but is not strictly speaking "biodegradable" under less favorable conditions (e.g., 28°C). PBAT has been certified as home compostable under such less favorable conditions. Some polyesters (e.g., PBAT) may be compostable under relatively low-temperature conditions (e.g., 28°C), while other such materials do not meet such criteria. The degree to which a given polyester plastic material biodegrades or is compostable varies from material to material. For example, PHA and PBAT may be two of the more readily biodegradable polyester polymer materials. PLA and PCL, as well as various other polyesters, may exhibit poor biodegradability under given conditions (e.g., less favorable conditions, such as 28°C). By homogeneously blending a carbohydrate-based polymeric material with specific properties (e.g., as exemplified by NuPlastiQ®), the degree and/or rate of biodegradability (especially under low-temperature home composting conditions) of PLA and possibly other similar polyester materials blended therewith is significantly increased. Current FTC Green guidelines stipulate that a plastic cannot be categorically claimed to be "degradable" unless it decomposes within a "reasonably short period" (most recently defined as within five years) after "normal disposal." The blends of the present invention provide the ability to meet the applicable guidelines, allowing for "pass" certification of home compostability for the blends of the present invention (e.g., NF T51-800 (2015), AS 5810 (2010), or TUV Austria Belgium's OK Compost Home certification scheme).

In some embodiments, NuPlastiQ® may be provided in a masterbatch formulation, which may include one or more of a carbohydrate-based polymer material, a polyester plastic material, and optionally a compatibilizer. Such a masterbatch may contain a high concentration of carbohydrate-based polymer material, for example, specifically configured to be mixed with pellets of polyester material during further processing to form a given article, effectively reducing the concentration of carbohydrate-based polymer material to a desired final value (e.g., the masterbatch may be approximately 50-80% NuPlastiQ®, while the finished article may contain 30-55% NuPlastiQ®). Any conceivable ratio can be used when mixing such different pellets, depending on the desired percentages of NuPlastiQ® and/or compatibilizer and/or polyester plastic material in the finished article.

The NuPlastiQ® materials described herein as suitable for use as carbohydrate-based (e.g., starch-based) polymeric materials are substantially amorphous. For example, raw starch powders (such as those used to make NuPlastiQ® and various other thermoplastic starch materials) have approximately 50% crystalline structure. The NuPlastiQ® materials available from BioLogiQ differ from many other commercially available thermoplastic starch (TPS) materials in terms of their crystallinity versus amorphous character. See, for example, Kris Frost's PhD thesis, "Thermoplastic Starch Composites and Blends" (September 2010), p. 62-63 state, "Of particular interest in TPS is the completeness of gelatinization during processing and any subsequent tendency toward retrogradation to form V-type amylose crystals." Frost continues, "Gelatinization, accompanied by heating with water and often the inclusion of other plasticizers or modifying polymers, involves the loss of granular and crystalline structure. Retrogradation is due to the rewinding of the amylose helical coil. Starch molecules disrupted during gelatinization slowly rewind into their original helical configuration, or a new single helical structure known as V-type, resulting in rapid embrittlement of the TPS film and loss of optical clarity." Thus, conventional TPSs tend to reform their crystalline structure after the gelatinization process used to produce TPS from raw starch. In contrast, NuPlastiQ® materials available from BioLogiQ remain amorphous virtually indefinitely and therefore rarely revert to a crystalline structure.

In contrast to typical TPS materials, NuPlastiQ® material, a suitable example of a starch-based polymer material for use in forming the articles described herein, has an amorphous microstructure and physical properties. The difference in molecular structure between conventional TPS and NuPlastiQ® material is evidenced by the fact that NuPlastiQ® material is much less crystalline than conventional thermoplastic starch-based materials, as shown by the X-ray diffraction shown in Figure 3, when comparing the resulting diffraction pattern of NuPlastiQ® GP with the native raw corn starch and native raw potato starch from which NuPlastiQ® GP is formed. The diffraction pattern of NuPlastiQ®, as seen in Figure 3, is much less crystalline (e.g., about 7% crystallinity) than native corn and potato starches (about 42% and 31% crystallinity, respectively). The differences in the diffraction patterns demonstrate that conversion from native starch to NuPlastiQ® (e.g., by a reactive extrusion process) has resulted in substantial chemical changes to the material. For example, while native starch has several prominent diffraction peaks between approximately 15 and 25°, the diffraction is quite different for the NuPlastiQ® material, exhibiting a much less intense "bell-curve" peak centered at approximately 20°. Interestingly, NuPlastiQ® exhibits a small peak at approximately 10°, whereas the starch material actually exhibits a trough at 10°, although the small peak at 10° for NuPlastiQ® is less intense than the trough for the native starch material. Across the spectrum, the diffraction intensity is higher for native starch than for NuPlastiQ®. The higher diffraction intensity seen across a broad spectrum indicates a higher degree of crystallinity for native starch compared to NuPlastiQ®. As can be seen, there are numerous differences.

By way of example, carbohydrate-based (e.g., starch-based) polymeric materials used in making films according to the present disclosure may have a crystallinity of less than about 40%, less than about 35%, less than about 30%, less than about 25%, less than about 20%, less than about 15%, less than about 10%, less than 9%, less than about 8%, less than 7%, less than about 6%, less than about 5%, or less than about 3%. Any suitable testing mechanism for determining crystallinity can be used, including, but not limited to, FTIR analysis, X-ray diffraction, and symmetric reflection and transmission techniques. A variety of suitable testing methods will be apparent to those skilled in the art.

In addition to differences in the chemical structure or microstructure of the finished NuPlastiQ® compared to the starting material, bags, other films, bottles, sheets, disposables, plates, cups, or other articles made from blends containing carbohydrate-based polymers differ from otherwise similar articles formed using only conventional TPS or starch powder, or polyester plastic materials. For example, articles formed by blending a carbohydrate-based polymer material, such as NuPlastiQ®, described herein with a polyester plastic material do not have the large "islands in the sea" particle size characteristic often seen when blending conventional TPS materials with other polymer materials. Rather, when Applicant's NuPlastiQ® material is used in the blend, a substantially uniform blend can be achieved. The uniform blend characteristics may be responsible for the observed accelerated or enhanced home compostability. Further details of the resulting uniform blend properties, including characterization of the small-sized starch particles, can be found in Applicant's patent application Ser. No. 62/872,582 (21132.27), filed July 10, 2019, which has been previously incorporated by reference in its entirety.

As described herein, blending the carbohydrate-based polymer materials described herein with blends of PBAT and PLA not only results in carbohydrate-based and PBAT materials that biodegrade under home composting conditions, but also results in the PLA being biodegradable under such home composting conditions, such that the entire blend can be certified under such applicable standards (e.g., NF T51-800(2015), AS 5810(2010), or TUV Austria Belgium's OK Compost Home certification scheme). Such a result does not necessarily occur when blending with typical TPS materials, but does occur with the blends of the present invention. As demonstrated by the various examples below, such differing results clearly demonstrate significant structural and/or chemical differences in NuPlastiQ® materials, and blends containing NuPlastiQ®, compared to conventional TPS materials, as the entire composite structure of the blend (i.e., film or other structure) can in turn be substantially completely biodegradable under home composting conditions.

Without being bound by any particular theory, it is believed that carbohydrate-based polymer resins may reduce the crystallinity of the blended product and interfere with the crystallinity and/or moisture-wicking barrier properties of the PLA polyester plastic material in a manner that allows water and bacteria to degrade the otherwise stable plastic molecular arrangements and bonds of the PLA in the blend with the carbohydrate-based polymer resin material. In other words, when ester-linked PLA monomers or other components of the polymer are uniformly blended with certain carbohydrate-based polymer materials as contemplated herein, they can be more easily decomposed and ultimately digested by microorganisms present in such environments. Microorganisms naturally present in home compost environments can consume such small molecules, converting them back into their natural components (CO ₂ , CH ₄ , H ₂ O, etc.). While the PBAT in the blend is already capable of doing so on its own without the addition of a carbohydrate-based polymer material, the rate and/or extent of biodegradation achieved in such conditions may be enhanced (e.g., faster and/or to a greater extent) when intimately blended with a carbohydrate-based polymer material.

For example, truly biodegradable plastics decompose through microbial assimilation (e.g., microbial enzymatic action on plastic molecules) into naturally occurring elements or compounds such as carbon dioxide, methane, water, inorganic compounds, or biomass. Biodegradation of plastics is made possible by initially breaking down the polymer chains through either chemical or mechanical action, but can only be achieved completely through the breakdown of the remaining molecules through microbial assimilation.

Plastics made from petrochemical feedstocks or derived from plant sources begin life as monomers (i.e., single small molecules that can chemically react with other small molecules). When the monomers combine together, they become polymers ("many parts") known as plastics. Before combining together, many monomers are readily biodegradable, but after combining together through polymerization, the molecules become so large that they combine in arrangements and bonds that microbial assimilation by microorganisms is impractical within any reasonable time frame under the contemplated conditions.

Polymers can be formed in both crystalline (orderly packed) and amorphous (randomly arranged) structures. Many polymers contain a high degree of crystallinity, with some amorphous regions randomly arranged and intertwined throughout the polymer structure.

NuPlastiQ® materials available from BiologiQ are formed from starting starch materials that are highly crystalline, but the finished NuPlastiQ® plastic resin material exhibits low crystallinity (i.e., is substantially amorphous). Such starch-based polymeric materials are used as starting materials in the manufacture of articles such as those described herein. NuPlastiQ® is therefore a plastic made from starch. As evidenced by the results of experimental testing contained herein, the molecules (size and linkages) of plastics made with NuPlastiQ®, due to their natural starch-based origin and carefully controlled linkage types, are highly susceptible to biodegradation by enzymatic reactions triggered by the introduction of water and bacteria or other microorganisms.

Like polyolefins such as polyethylene and polypropylene, polyesters typically have high crystallinity and are made by converting monomer molecules (whether derived from petroleum or from small building block molecules derived from lactic acid or other plant sources) into long-chain polymers. In polyesters, the bonds between monomers are naturally ester bonds. The bonds formed when connecting monomers to form long polymer chains can be relatively strong and difficult to break, with the degree of difficulty varying between different types of polyesters. For example, the bonds in PBAT (and PHA) are more easily broken than those in PLA. While many synthetic polyesters (including both PBAT and PLA) exhibit significant biodegradability under high-temperature composting conditions (e.g., 58°C), and PBAT also exhibits sufficient biodegradability to meet home compostability standards (e.g., 28°C), PLA cannot meet home compostability standards by itself or even when blended with PBAT. Blending such materials with Applicant's NuPlastiQ® materials changes that.

In addition to enhanced home compostability, in some embodiments, the resulting polyester blends of the present invention may have a higher modulus (stiffness or strength) than one or both of the polyester plastic materials alone, allowing them to be used to make plastic films or other articles that are at least as strong as, or stronger than, the same article made from a given one of the pure polyester plastic materials alone. For example, PBAT alone exhibits relatively low stiffness but excellent elongation. PLA has a significantly higher modulus, and blending NuPlastiQ® and PLA into PBAT increases the modulus of the resulting blend compared to PBAT alone. In other embodiments, depending on the properties of the polyester materials blended together, strength properties may be reduced but still sufficient for the desired purpose. By way of example, such blends may provide dart drop strengths of at least 130 g, at least 140 g, at least 150 g, at least 160 g, at least 175 g, at least 200 g, at least 225 g, at least 250 g, at least 275 g, or at least 300 g at a thickness of about 25 μm (1 mil). Increasing thickness generally results in increased strength. The percentage of carbohydrate-based polymer material in the blend can be, for example, 1% to 70%, 10% to 65%, 20% to 55%, 30% to 55%, etc., as described herein or in Applicant's other applications. Figure 3A shows strength data for films of various thicknesses compared to various other materials (e.g., 100% PBAT, 100% LLDPE, and a 25% blend of NuPlastiQ® and LLDPE). The sample labeled BC27241 in Figure 3A contained 35% NuPlastiQ®, 11% PLA, and 54% PBAT. The sample labeled BC27251 in Figure 3A contained 41% NuPlastiQ®, 11% PLA, and 48% PBAT.

Figure 4 shows molecular weight data for an exemplary NuPlastiQ® (e.g., the same NuPlastiQ® GP as in Figure 3) material. As shown, the average molecular weight (i.e., weight average molecular weight) can be approximately 900,000 g/mol. For example, the weight average molecular weight can be greater than 200,000 g/mol, greater than 300,000 g/mol, greater than 400,000 g/mol, greater than 500,000 g/mol, greater than 600,000 g/mol, greater than 700,000 g/mol, 500,000 to 5,000,000 g/mol, 500,000 to 3,000,000 g/mol, 500,000 to 2,000,000 g/mol, 500,000 to 1,000,000 g/mol, or 800,000 to 1,000,000 g/mol.

Figure 5 shows transmittance data for the same materials compared in the X-ray diffraction charts of Figure 3. It is readily apparent that the O-H scissor peak at 1653 ^cm is significantly reduced for the NuPlastiQ® material compared to the native corn and potato starch materials. This reduced incidence of OH groups is consistent with the lower wettability shown in Figure 6.

Figure 6 shows a comparison of the wetting properties of a conventional blend of polyolefin and a conventional TPS material, having a wettability of greater than 46 mN/m (46 dynes/cm), compared to an exemplary blend of polyolefin and NuPlastiQ® GP (right), having a wettability of less than 34 mN/m (34 dynes/cm). In both examples, the starch-based polymer content is believed to be 20-25%. While this figure uses a polyolefin blend (rather than polyester), the comparison demonstrates the hydrophobicity of the NuPlastiQ® GP material compared to the hydrophilicity of conventional starch materials. The PBAT and PLA materials used in the blends described herein typically exhibit hydrophobic properties similar to those of polyolefins. For example, such materials often have wettability values of less than 40 mN/m (40 dynes/cm), less than 38 mN/m (38 dynes/cm), less than 36 mN/m (36 dynes/cm), less than 34 mN/m (34 dynes/cm), or 30-40 mN/m (30-40 dynes/cm) when used in a dyne test. NuPlastiQ® materials exhibit wetting properties similarly consistent with hydrophobic polyesters, e.g., less than 40 mN/m (40 dynes/cm), less than 38 mN/m (38 dynes/cm), less than 36 mN/m (36 dynes/cm), or less than 34 mN/m (34 dynes/cm). The surface wettability dyne test may be in accordance with, for example, DIN 53394/ISO 8296. Such matched hydrophobicity between the NuPlastiQ® material and the polyester material with which it is blended may be responsible for its ability to achieve the biodegradable properties described herein.

Figure 7 illustrates comparative DSC melting temperature data for conventional starch materials, showing a melting temperature of 287.7°C, much higher than the melting temperature of NuPlastiQ®, which is approximately 170°C.

FIG. 8 shows the TGA temperature stability profile of the NuPlastiQ® GP material compared to the starting glycerin and native starch materials.
Returning to FIG. 1 , at 106, the process 100 includes mixing the polyester plastic material and the carbohydrate-based polymer material to produce a material mixture. In some cases, mixing the polyester plastic material and the carbohydrate-based material can be performed using one or more mixing devices. In certain implementations, a mechanical mixing device can be used to mix the polyester plastic material and the carbohydrate-based polymer material. In implementations, at least a portion of the components of the material mixture can be combined in an apparatus such as an extruder, an injection molding machine, or the like. In other embodiments, at least a portion of the components of the material mixture can be combined before being fed into the apparatus.

The carbohydrate-based polymer material can be present in the blend in an amount at least sufficient to enhance the biodegradability of the PLA polyester plastic material of the blend, such that the blend passes any of various applicable home compostability standards. Of course, amounts greater than such threshold amounts may be included (e.g., to further enhance biodegradability and/or increase the renewable content of the blend, etc.). By way of example, the carbohydrate-based polymer material can be included in an amount of at least 1% by weight, at least 5% by weight, at least 10% by weight, up to 70% by weight, up to 60% by weight, between 1% and 70% by weight, between 10% and 65% by weight, between 20% and 55% by weight, or between 30% and 55% by weight of the blend of materials. If desired, more than one carbohydrate-based polymer material and/or more than two polyester plastic materials can be included in the blend.

The first polyester plastic material (e.g., PBAT) may be present in the blend of materials in an amount of at least 20%, at least 25%, at least 30%, at least 35%, 20% to 85%, 30% to 70%, or 30% to 60% by weight of the blend of materials. The second polyester plastic material (e.g., PLA) may be present in the blend of materials in an amount of at least 1%, at least 3%, at least 5%, at least 6%, at least 7%, at least 8%, at least 9%, or at least 10%, at least 11%, 50% or less, 40% or less, 30% or less, 20% or less, 15% or less, 1% to 20%, 1% to 15%, 1% to 12%, 3% to 15%, 5% to 15%, or about 10% to 15% by weight of the blend of materials.

Applicable home compostability standards accept any test results that result in greater than 90% biodegradation, but the standards also require that any ingredient included in a blend at 10% or less of the blend pass on its own, ensuring that this material, which may be present in trace amounts, actually passes the applicable standard.

While a compatibilizer may be present in the blend of materials, it is generally not required. In one embodiment, such a compatibilizer may not be included. If present, the compatibilizer may be blended with the polyester plastic material, blended with the carbohydrate-based polymeric material, blended with both, or provided separately. Often, the compatibilizer is provided with at least one of the polymeric materials, for example, in a masterbatch formulation. The compatibilizer may be a modified polyester such as a maleic anhydride-grafted polyester (e.g., maleic anhydride-grafted PBAT or PLA). The compatibilizer may also include an acrylate-based copolymer. Additionally, the compatibilizer may include a poly(vinyl acetate)-based compatibilizer. In one embodiment, the compatibilizer may be a grafted version of a polyester plastic material (e.g., a maleic anhydride-grafted polyester) or a copolymer (e.g., a block copolymer) in which one of the blocks is the same monomer as the polyester plastic material (e.g., a polyester copolymer). In at least some embodiments, a compatibilizer may not be required and therefore is not present.

When included, the blend of materials may contain at least 0.5% by weight, at least 1% by weight, at least 2% by weight, at least 3% by weight, at least 4% by weight, at least 5% by weight, 50% by weight or less, 45% by weight or less, 40% by weight or less, 35% by weight or less, 30% by weight or less, 25% by weight or less, 20% by weight or less, 15% by weight or less, 10% by weight or less, 9% by weight or less, 8% by weight or less, 7% by weight or less, 6% by weight or less, 5% by weight or less, 4% by weight or less, 3% by weight or less, 0.5% to 12% by weight, 1% to 7% by weight, or 1% to 6% by weight of compatibilizer. Due to cost considerations, the lowest effective amount of compatibilizer (or no compatibilizer) may generally be used.

While not necessarily required, and in at least some embodiments, it may be advisable to avoid its inclusion, it is within the scope of the present invention to include any of a variety of UV and/or OXO degrading additives. Further details of such additives are described in Applicant's U.S. Patent Application No. 16/391,909 (21132.14.1), which is incorporated herein by reference in its entirety. Other additives may be included, for example, to enhance strength (e.g., DuPont's Biomax® Strong) or for other purposes.

The one or more additives may be included in the mixture of materials in an amount of at least 0.5% by weight, at least 1% by weight, at least 1.5% by weight, at least 2% by weight, at least 2.5% by weight, at least 3% by weight, at least 4% by weight, 10% by weight or less, 9% by weight or less, 8% by weight or less, 7% by weight or less, 6% by weight or less, 5% by weight or less, 0.2% to 12% by weight, 1% to 10% by weight, 0.5% to 4% by weight, or 2% to 6% by weight of the mixture.

While primarily described in the context of mixtures of thermoplastic materials that can be melted together to form a desired blend, in some embodiments, it may be possible to blend a carbohydrate-based polymeric material with a plastic material that is not thermoplastic (e.g., a thermosetting polyester or other thermosetting plastic material that may be included in the blend). For example, a resin component that is a precursor to such a non-thermoplastic polyester plastic material may be blended with the carbohydrate-based polymeric material, and polymerization or other formation of the polyester material may occur in the presence of the carbohydrate-based polymeric material, resulting in a finished product that is a blend of the carbohydrate-based polymeric material and the thermosetting material or other non-thermoplastic plastic material, and the carbohydrate-based polymeric material may enhance the biodegradability of a given polymeric component included in the blend.

Referring again to FIG. 1 , at 108, the process 100 can include heating the mixture of materials, particularly if the materials are thermoplastic. In practice, the mixture of materials can be heated to a temperature of at least 100°C, at least 110°C, at least 115°C, at least 120°C, at least 125°C, at least 130°C, at least 135°C, at least 140°C, 200°C or less, 190°C or less, 180°C or less, 175°C or less, 170°C or less, 165°C or less, 160°C or less, 155°C or less, 150°C or less, 95°C to 205°C, 120°C to 180°C, or 125°C to 165°C. It will of course be understood that in some embodiments, the mixture can be heated to a temperature greater than 200°C.

Heating of such materials can be carried out, for example, in a multi-stage extruder in which progressive stages are heated to higher temperatures than the previous stage, with each extruder stage heating the mixture of materials to a given temperature, as disclosed in various applicant's patent applications previously incorporated by reference. In one embodiment, the temperature of the first stage of such an extruder for blending can be in the same range (e.g., 120-140°C) as the temperature of the carbohydrate-based polymer material (e.g., NuPlastiQ®) in the final stage of the reactive extrusion process from which it was produced, as described in applicant's U.S. patent applications Ser. Nos. 62,872,582 (21132.27) and 62/939,460 (21132.27.1), filed July 10, 2019 and November 22, 2019, respectively. As described in those applications, Applicant has discovered that controlling the conditions under which starch and other components (such as plasticizers) are maintained during the preparation of NuPlastiQ® contributes to the desired formation of a starch-based polymer material that, when blended with other polymers, has a small particle size and tight distribution in the final blend of starch-based polymer material. Accordingly, during reactive extrusion of the starch-based polymer material, the material is maintained at a temperature of 110°C to 160°C, preferably 120°C to 140°C (e.g., about 130°C), in the final stage of the extruder before mixing with other polymers, such as polyesters, polyolefins, etc. It will be apparent that this careful temperature control during the final stage of the reactive extrusion step in forming a starch-based polymer material differs from the control of the temperature in the extruder when blending such already-formed starch-based polymer material with other polymers with which it is blended. While such temperatures may be similar, the components present in such stages are entirely different (e.g., "other polymers," such as polyesters, are typically not present in the stages described herein).

The mixture of materials including the polyester plastic material and the carbohydrate-based polymer material can be heated in one or more chambers of the extruder. In some cases, one or more chambers of the extruder can be heated at different temperatures. The speed of one or more screws of the extruder can be set at any desired speed.

Of course, it is also possible to heat one material first and then add a second and/or third material in a subsequent (e.g., downstream) charge, which is heated after the previous material, so that all materials can be melt-blended together. Figure 1 is intended to cover all such conditions.

At 110, an article is manufactured using the mixture of materials. In some cases, the article can include a film. In other cases, the article can be formed from a film. In other embodiments, the article can have a shape based on the design of a mold (e.g., injection molding) or the like. Any conceivable article formed from plastic can be formed from the mixture, including, but not limited to, films, bags, bottles, caps, lids, sheets, boxes, plates, cups, utensils, etc. If the article is a film, the film can be formed using a die by injecting gas into a heated mixture of materials to form a film (i.e., blowing the film). Cast film is also possible. The film can be sealed and/or otherwise modified to form a bag or other article.

When the article is a film, the film may be comprised of a single layer or multiple layers. The film or any individual layer may have a thickness of at least 0.001 mm, at least 0.002 mm, at least 0.004 mm, at least 0.01 mm, at least 0.02 mm, at least 0.03 mm, at least 0.05 mm, at least 0.07 mm, at least 0.10 mm, 2 mm or less, 1 mm or less, 0.5 mm or less, 0.1 mm or less, about 0.05 mm to about 0.5 mm, or 0.02 mm to 0.05 mm. While there may be some overlap in the thickness values for film and sheet articles, it will be understood that sheet materials of greater thickness than such film values can, of course, be provided (e.g., 2 mm or more, e.g., 2-100 mm or 2-10 mm) and manufactured by any desired plastic manufacturing process.

Films or other articles may have strength properties characterized by tests such as the Dart Drop Impact Test (ASTM D-1709), the Tensile Strength at Break Test (ASTM D-882), the Tensile Elongation at Break Test (ASTM D-882), the Secant Modulus Test (ASTM D-882), and/or the Elmendorf Tear Test (ASTM D-1922). Exemplary values for such properties are provided in other applications of various applicants, which have been previously incorporated by reference herein.

When biodegradation tested under relatively low temperature, "home compost"-like conditions (e.g., EN 13432, which may be similar to the industrial compost test in ASTM Standard D-5338, but conducted at 28°C instead of 58°C), the blends of the present invention exhibit at least 90% (or greater) biodegradation within 365 days, which is sufficient to meet the biodegradability portion of applicable "home compostability" standards, such as NF T51-800(2015), AS 5810(2010), and TUV Austria Belgium's OK Compost Home certification scheme. Such standards are incorporated herein by reference in their entirety. Biodegradation of 90% or more may be achieved faster than the permitted 365 days, for example, within 350 days, 325 days, 300 days, 275 days, 250 days, 200 days, or 180 days.

While biodegradation under home composting conditions is specifically contemplated, it will be understood that enhanced biodegradation may also be demonstrated under other waste environments, such as, for example, anaerobic digester environments (e.g., simulated by ASTM D-5511 or D-5526) or marine conditions (e.g., simulated by ASTM D-6691).

When subjected to biodegradation testing, articles having about 2% by weight or less (or preferably no biodegradation-promoting additive) and the amounts of carbohydrate-based polymer material and polyester plastic material described herein can exhibit enhanced home compostability as a result of the incorporation of the carbohydrate-based polymer material into the article. For example, at least 90%, or even at least 95%, of the polyester polymer material or blend (e.g., or their carbon atoms) may biodegrade over a period of 365, 300, 200, or even 180 days. In either case, the degree of degradation of the PLA material of the blend, and of the blend as a whole, will be greater than the degree of degradation exhibited by the material without the addition of NuPlastiQ® or other carbohydrate-based polymer material. Such enhanced biodegradation is particularly advantageous because it enables the formation of bags (e.g., takeout bags) or other films that can include PLA in the polyester blend while still meeting applicable home compostability standards.

Figure 2 illustrates components of an exemplary manufacturing system 200 for producing articles according to the present disclosure. In some cases, manufacturing system 200 can be used in process 100 of Figure 1. In an illustrative example, manufacturing system 200 is an extruder, such as a single-screw extruder or a twin-screw extruder.

In one embodiment, two or more polyester plastic materials (e.g., PBAT and PLA) and one or more carbohydrate-based polymer materials are provided via first hopper 202 and second hopper 204. More than two hoppers may be provided. A compatibilizer may optionally be included in either or both materials (e.g., in the masterbatch). In one embodiment, no compatibilizer is included, or a minimal amount thereof (e.g., less than 5%, less than 4%, less than 3%, less than 2%, less than 1%, or less than 0.5%). Calcium carbonate or other filler materials (e.g., whether inorganic fillers such as calcium carbonate or talc, or suitable organic fillers) may be added separately or included in the masterbatch. In an exemplary embodiment, the carbohydrate-based polymer materials may be compounded into the masterbatch (e.g., with any optional compatibilizer) prior to placing pellets of such masterbatch into hopper 204. Such masterbatches, of course, may also include a portion of the polyester plastic material therein.

One or more carbohydrate-based polymeric materials and PBAT, PLA, or other polyester plastic materials can be mixed in the first chamber 206 to produce a mixture of materials. In some cases, the mixture of materials can include 5% to 60% by weight of one or more carbohydrate-based polymeric materials and 40% to 95% by weight of PBAT, PLA, or other polyester plastic materials. When inorganic or other filler materials (e.g., calcium carbonate and/or talc) are included, they can be present at 0% to 30% by weight, or up to 20% by weight. The percentage of polymeric material can be relative to the entire blend (e.g., including any fillers and/or compatibilizers) or can be relative to the polymeric material only. Of course, ranges can vary outside of the above or other ranges described herein depending on the desired properties.

One exemplary composition may include 30% to 55% carbohydrate-based polymer material, at least 10%, at least 15%, at least 20%, at least 25%, up to 90%, up to 85%, up to 80%, 10% to 80%, 20% to 70%, or 30% to 60% PBAT, up to 60%, up to 50%, up to 40%, up to 30%, up to 20%, or up to 15% PLA (e.g., 1% to 15%, or 1% to 12% PLA), and 0% to 30% (e.g., 0%, 5%, 10%, 15%, 20%, 25%, 30%) calcium carbonate or other filler. A compatibilizer may or may not be present. All else being equal, a higher percentage of PLA may biodegrade more slowly but still meet the 90% threshold of the criteria within 365 days. For example, including a PLA loading of up to 20% or up to 15% may result in a blend that can meet the standard's 90% threshold within 200 days, or even 180 days.

2, the mixture of materials may pass through several chambers, such as a first chamber 206, a second chamber 208, a third chamber 210, a fourth chamber 212, a fifth chamber 214, and an optional sixth chamber 216. The mixture of materials may be heated in chambers 206, 208, 210, 212, 214, and 216. In some cases, the temperature of one of the chambers may be different from the temperature of another chamber. In an illustrative example, the first chamber 206 is heated to a temperature of 120°C to 140°C, the second chamber 208 is heated to a temperature of 130°C to 160°C, the third chamber 210 is heated to a temperature of 135°C to 165°C, the fourth chamber 212 is heated to a temperature of 140°C to 170°C, the fifth chamber 214 is heated to a temperature of 145°C to 180°C, and the optional sixth chamber 216 is heated to a temperature of 145°C to 180°C.

The heated mixture can then be extruded using a die 218 to form an extrudate, such as a film or sheet. Injection molding, thermoforming, or other plastic manufacturing processes can be used to produce a variety of articles, such as bags (e.g., take-out bags), agricultural mulch (weed barriers), other films, utensils, plates, cups, bottles, caps, or lids. In blown-film extrusion, gas can be injected into the extrudate to expand it at pressures of 105 bar to 140 bar. The resulting tube 220 can be stretched by rollers 222 to produce a film 224, typically 0.02 mm (approximately 0.8 mil) to 0.05 mm (approximately 2 mil) thick. Even thinner films, e.g., having thicknesses of only 0.1 mil (0.004 mm), can be produced using the blends described herein. Of course, thicknesses greater than 2 mils can also be achieved. In some cases, the film 224 can be composed of a single layer. In other cases, the film 224 can be composed of multiple layers. When multiple layers are present, at least one of the layers may comprise a carbohydrate-based polymer material. In some embodiments, the carbohydrate-based polymer material may be present in one or more outer layers, an inner layer, or all layers.

The concepts described herein are further illustrated in the following examples. Some of the following examples demonstrate greater than 90% biodegradation of the composite blend and/or greater than 90% biodegradation of its polyester components (PBAT and/or PLA) within 365 days.

Biodegradation can be determined according to a carbon mass balance, as is customarily done in respirometry-based tests, whereby carbon atoms evolved in the materials of the blend (e.g., the carbohydrate-based polymeric material and/or the polyester) are accounted for in the off-gas products as _CH4 and/or _CO2 as a result of biodegradation. For example, at least 90% of the carbon atoms in either the polyester or the entire blend can become at least one of _CO2 or _CH4 within 365 days (or 300 days, or 200 days, or 180 days, etc.) in such simulated home composting conditions. To pass the NF T51-800 (2015), AS 5810 (2010), or TUV Austria Belgium's OK Compost Home certification scheme, a blend must meet the following requirements: (1) a certified solid heavy metals "pass" rating for all components (e.g., PBAT, PLA, and carbohydrate-based polymeric materials in the blend) in accordance with, for example, ASTM D6400; (2) conversion of at least 90% of the carbon in the sample to _CO or CH at ₃₆₅ days in accordance with EN 13432; (3) a "pass" rating for decay in accordance with, for example, ISO 20200; and (4) a "pass" rating for exotoxicity for all components in the blend in accordance with, for example, OECD Guideline 208, ASTM D6400, etc. The samples shown in the following examples meet these requirements.

Example 1
Films made from blends of NuPlastiQ®, PBAT, and PLA were tested according to standard controlled composting biodegradation tests over 195 days in accordance with ASTM D5338 and/or EN 13432 at a temperature of 28±2°C, intended to mimic home composting conditions. The tested films are designated BC27130 and BC27241 in Table 2 and Figure 9. Table 2 and Figure 9 show the results after 179 days of the 195-day test. After 179 days, samples BC27130 and BC27241 exhibited adjusted biodegradation values of 75.3% and 81.8%, respectively (compared to the cellulose control). Specifically, sample BC27130 contained 30% NuPlastiQ® and 70% PBAT. Sample BC27241 contained 35% NuPlastiQ®, 11% PLA, and 54% PBAT. No compatibilizer was present in either sample. Both films had thicknesses of 38-51 μm (1.5-2 mils).

The biodegradation rates of the cellulose controls exceeding 100% can be explained by a synergistic effect known as priming. In both cases, the absolute biodegradation of test samples BC27130 and BC27241 was measured at 79.2% and 86%, respectively. The notation in Figure 9 indicates that the samples were reinoculated with 20% fresh vegetable, horticultural, and fruit waste (VGF) on day 46 of the test. The results in Table 2 and Figure 9 indicate that the samples are on track to reach greater than 90% biodegradation under home composting conditions within 365 days, thus meeting the criteria for home compostability.

Example 2
To meet the home compostability standards NF T51-800 (2015), AS 5810 (2010), or TUV Austria Belgium's OK Compost Home certification scheme, a sample film must also demonstrate disintegration under such home composting conditions within 26 weeks. Figure 10A shows the disintegration progression of sample BC27240/1 (similar to sample BC27241 in Example 1 above) over the 26-week (182-day) test. Test sample BC27240/1 (62 microns thick) was placed in a slide frame and mixed with compost inoculum. The resulting mixture was incubated in the dark at ambient temperature (28 ± 2°C). Tests were performed in two replicates. Figure 10A shows photographs visualizing the progression of disintegration of test material BC27240/1 during 26 weeks of composting at ambient temperature. After 20 weeks, only a small edge of the test material remained on most of the slide frames. Furthermore, it was noted that loose fragments of film could be easily retrieved from the composting reactors. To regenerate the microbial population and provide fresh nutrients, all reactors were reinoculated with 5% fresh VGF waste after the 18-week incubation period. After 26 weeks, an average disintegration rate of at least 90% had been reached, based on any surface of the test material still within the slide frames. After 26 weeks, no loose fragments of test material were observed in the compost inoculum.

The French standard NFT 51-800 Plastics - Specification for Plastics Suitable for Home Composting (2015) and the TUV AUSTRIA Belgium OK Compost Home certification scheme state that a material has demonstrated sufficient disintegration for home composting if it passes the 90% disintegration requirement in a quantitative test conforming to ISO 16929 (Plastics - Determination of the Degree of Disintegration of Plastic Materials under Specified Composting Conditions in Pilot-Scale Tests (2013)) and, in a qualitative test conforming to ISO 20200 at ambient temperature (20°C to 30°C, e.g., 28°C ± 2°C), (1) after 26 weeks, at least 81% of the surface of the test material in the slide has disappeared, and (2) no discernible test material remains in the compost after the test.

According to Australian Standard AS5810 Biodegradable Plastics - Biodegradable Plastics Suitable for Home Composting (2010), the criteria for disintegration in the slide frame test is that 90% of the test material disintegrates from the slide frame and any remaining residue is indistinguishable from other materials in the 500mm compost when observed with the naked eye.

Based on these results, and assuming the 90% disintegration requirement of EN 13432 Requirements for compostable and biodegradable recoverable packaging - Test schemes and evaluation criteria for final approval of packaging (2000) is met (100% disintegration achieved), BC27240/1 of the tested thickness meets the disintegration requirements according to French standard NF T51-800 (2015), the OK Compost HOME conformity mark, and Australian standard AS 5810 (2010).

Example 3
Summary and Conclusions: Figure 10B shows photographs of samples BC27130 and BC27251 (left and right, respectively) before disintegration testing began. Sample BC27251 contained 41% NuPlastiQ®, 11% PLA, and 48% PBAT. No compatibilizer was present. In a laboratory-scale composting test mimicking a home composting process, the disintegration of 49 μm-thick specimens BC27130 and 34 μm-thick specimens BC27251 was evaluated at ambient temperature (28°C). As with other examples herein, the test procedure was based on ISO 20200 (2015). Test materials BC27130 and BC27251 were added at a concentration of 0.5% as 2.5 cm x 2.5 cm pieces to an 80/20 mixture of less than 10 mm mature compost and ground fresh vegetable, horticultural, and fruit waste (VGF). The test was conducted in triplicate and lasted 17 weeks. At the end of the composting test, the compost was sieved and assessed for disintegration.

Disintegration of 2.5 cm x 2.5 cm pieces of BC27130 (49 μm) and BC27251 (34 μm) proceeded very well. Disintegration of BC27130 proceeded somewhat faster than that of BC27251. After 14 weeks of composting, all test material for BC27130 appeared to be completely decomposed, and the same result was obtained for BC27251 after 2 weeks. At the end of the ambient temperature composting test (after 17 weeks), the entire contents of the test reactor were used for sieving, screening, further separation, and analysis. Disintegration is defined as size reduction to less than 2 mm. For both test articles, no test article fragments were recovered in the fraction greater than 2 mm. A disintegration rate of 100.0% was obtained for BC27130 at 49 μm thickness and BC27251 at 34 μm thickness.

The French standard NFT 51-800 Plastics - Plastics - Specification for plastics suitable for home composting (2015), the Australian standard AS 5810 Biodegradable plastics - Biodegradable plastics suitable for home composting (2010), and TUV AUSTRIA Belgium's OK Compost HOME certification scheme ISO 20200 (2015) state that in a quantitative test according to ISO 20200 (2015) at ambient temperature (20°C-30°C), a material has demonstrated sufficient decomposition for home composting if, after 26 weeks of composting, at least 90% of the test material has shrunk to a size of less than 2 mm.

Introduction - Objectives and Test Methods For the 49 μm thick test material BC27130 and the 34 μm thick test material BC27251, complete disintegration was already obtained after an incubation period of 17 weeks at ambient temperature, so it can be concluded that the 90% disintegration criteria of NF T51-800 (2015), AS 5810 (2010) and the OK Compost HOME certification scheme of TUV AUSTRIA Belgium were easily reached. Even at greater thicknesses, both materials have the potential to reach this requirement.

The purpose of this test was to evaluate the disintegration of materials at ambient temperatures in an 80/20 mixture of less than 10 mm mature compost and ground fresh vegetable, horticultural, and fruit waste (VGF). During home composting, the high temperatures (>50°C) achieved in industrial composting processes are not typically reached. Therefore, materials must demonstrate sufficient disintegration at ambient temperatures before home composting is possible.

Each test article was mixed with an 80/20 mixture of less than 10 mm mature compost and ground fresh vegetable, horticultural, and fruit waste (VGF) and incubated in the dark at 28°C. Moisture content was checked periodically and adjusted as needed. The reactor contents were manually stirred periodically and the test articles were visually monitored. The maximum test period for which disintegration was to be demonstrated was 26 weeks.

At the end of the test, the compost from each reactor was sieved through a vibrating sieve larger than 2 mm to recover any undegraded test material residues in the larger than 2 mm fraction. Disintegration was assessed very accurately by manual selection. Where possible, a mass balance was calculated. The compost obtained at the end of the composting process could be used for further measurements, such as chemical and physical analyses.

The test procedure is based on ISO 20200 Plastics - Determination of the degree of disintegration of plastic materials under laboratory-scale simulated composting conditions, with the following deviations compared to ISO 20200 (2015):

- Incubation at 28°C ± 2°C to mimic home composting conditions.
• Instead of 1 kg of synthetic solid waste per reactor, use 2 kg of a mixture of less than 10 mm mature compost and VGF per reactor.

Instead of the monitoring process specified in ISO 20200 (2015), visually monitor disintegration once a week, assess moisture status and adjust as necessary.
The test is considered valid (when performed with thermophilic and mesophilic incubation periods) if:

The degree of decay of the three replicates does not differ by more than 10%.
Test item Test item 1
・Name: BC27130
Explanation: Plastic film (Fig. 10B)
- Color: Off-white - Thickness: 49 μm ± 2 μm
Total solids (TS): 94.4%
Volatile solids (VS): 99.1% based on TS
Sample preparation: Cut into 2.5cm x 2.5cm pieces Test piece 2
・Name: BC27251
Explanation: Plastic film (Fig. 10B)
- Color: Off-white - Thickness: 34 μm ± 2 μm
Total solids (TS): 90.9%
Volatile solids (VS): 99.0% based on TS
Sample preparation: cut into 2.5cm x 2.5cm pieces Analytical methods Dry matter or total solids Dry matter is determined by drying at 105°C for at least 14 hours and weighing as described in 'M_009. Moisture content determination Dry matter is expressed as a percentage of wet weight.

pH
Measure the pH with a pH meter after calibration with standard buffers (pH=4.00, pH=7.00, and pH=10.00) as described in 'M_006. pH and conductivity measurements. Dilute the sample with distilled water in a 5 to 1 ratio (5 parts demineralized water to 1 part sample) and mix thoroughly before inserting the electrode as described in 'M_012. Preparation of extracts and solutions.

Thickness (plastic)
After an acclimatization period of 24 hours at 23° C., 10 points on the specimen are measured. The measurements are carried out with a universal bench micrometer (accuracy 0.1 μm) in accordance with ISO 4593 Plastics - Films and sheets - Measurement of thickness by mechanical scanning.

Total nitrogen (N)
The analysis is performed as described in 'M_039. Total Organic Carbon and Total Nitrogen Determination - Total Carbon, Total Nitrogen, Inorganic Carbon Combustion Method. The sample is combusted at 950-1200°C and nitrogen components are oxidized to nitrogen oxides (NOx) by briefly adding a controlled amount of extra oxygen. In the presence of a CuO catalyst and copper reductant, the nitrogen oxides are converted to _N2 . The _N2 formed is measured by a thermal conductivity detector (TCD). Results are given in g/kg of total solids.

Volatile Solids - Ash Determine the volatile solids and ash content by heating a dried sample at 550°C for at least 4 hours and weighing as described in 'M_010. Determination of organic matter and carbon content. Results are given as percent of dry matter.

Weight measurements Two types of balances are used during the test: a Sartorius AC 210S with internal calibration (max. 200 g; d = 0.1 mg) for the measurement of dry matter and volatile substances, and a Sartorius CPA 12001 S (max. 12100 g, d = 0.1 g) used to weigh the different components of the test article and inoculum.

Results Thickness of Test Pieces The results of the thickness measurements of BC27130 and BC27251 are shown in Table 3.

For each test article, three reactors measuring 30 cm x 20 cm x 13 cm (length, width, height) were set up for quantitative assessment of disintegration. The reactors contained an 80/20 mixture of 16-week-old, <10 mm mature compost and ground fresh vegetable, horticultural, and fruit waste (VGF), as well as 0.5% 2.5 cm x 2.5 cm pieces of BC27130 or BC27251. A 0.5% test article concentration was used for the determination and quantitative assessment of test article disintegration. Details of the test setup for the quantitative tests are shown in Table 4.

Biowaste analysis The characteristics of the inoculum are shown in Table 5. The inoculum is characterized by an optimal moisture content for composting (56.7%), with a C/N ratio of 9 ensuring sufficient nitrogen levels. A normal pH of 7.0 was measured.

Visual During the composting process, the reactor contents were mixed weekly and water was added as needed to ensure optimal moisture conditions. During the test, the test material was carefully inspected for disintegration.

Disintegration of 2.5 cm x 2.5 cm fragments of both 49 μm-thick BC27130 and 34 μm-thick BC27251 proceeded well. Figures 10C and 10D show a visual comparison of 2.5 cm x 2.5 cm fragments of BC27130 and BC27251, respectively, at the beginning of composting at ambient temperature and after a 4-week incubation period. After 4 weeks, small holes were observed in both test materials. The amount of small holes was significantly greater in BC27130 (approximately 80% of the test material) compared to BC27251 (approximately 25% of the test material). After 4 weeks (i.e., at week 8), BC27130 began to disintegrate, with the average size of the resulting fragments being approximately 1.5 cm x 1.5 cm (Figure 10E). Figure 10F shows the fragments obtained with BC27251 at week 8. We also noticed that both test materials had turned brown in color. As degradation progressed, after 12 weeks of composting, only a few fragments of BC27130 could be recovered from the composting reactor (Figure 10G), and BC27251 had also broken down into smaller fragments (Figure 10H). Over the next few weeks, the amount and size of the remaining fragments further decreased. After 14 weeks of composting, no fragments of BC27130 could be found in the composting reactor (Figure 10I), and after two weeks (16 weeks), BC27251 had also completely degraded (Figure 10J).

Sieving - Disintegration At the end of the test (after 17 weeks), the reactor contents were dried. During the drying process, compost clumps were gently broken down. The drying process was terminated when a constant mass was reached. The compost from each reactor was sieved through a vibrating sieve larger than 2 mm to recover any residual undecomposed test material in the fraction larger than 2 mm. Table 6 shows that for both test articles, no test material remained in the fraction larger than 2 mm in all replicates. The validity requirements of ISO 20200 (2015) were met.

The French standard NFT 51-800 Plastics - Specification for Plastics Suitable for Home Composting (2015), the Australian standard AS 5810 Biodegradable Plastics - Biodegradable Plastics Suitable for Home Composting (2010), and TUV AUSTRIA Belgium's OK Compost HOME certification scheme ISO 20200 (2015) state that in a quantitative test according to ISO 20200 (2015) at ambient temperature (20°C-30°C), a material has demonstrated sufficient decomposition for home composting if, after 26 weeks of composting, at least 90% of the test material has reduced in size to less than 2 mm.

For test materials BC27130 and BC27251, complete disintegration was achieved before 26 weeks, and therefore it can be concluded that the 90% disintegration criteria of NF T51-800 (2015), AS 5810 (2010), and the OK Compost HOME certification scheme of TUV AUSTRIA Belgium were easily reached.

The test materials BC27130, BC27251 are subject to OK Compost HOME certification regarding disintegration requirements.
Chemical Analysis Table 7 shows the results of the chemical analysis at the end of the test. Equivalent volatile solids were measured for the different replicates, giving normal pH values. The C/N ratio of the different replicates was 8.

While described primarily in the context of PBAT as the primary or key component of the blend, it is understood that other polyester-based polymer materials may be used, for example, instead of or in addition to PBAT. For example, other polyester-based polymer materials with relatively low stiffness (modulus) include, but are not limited to, PCL and PBS. Where such materials may have similarly low stiffness, high flexibility, and/or high toughness (and low strength), they may similarly benefit from blending with PLA or a similarly stiff polyester to increase stiffness, and, if a carbohydrate-based polymer material such as NuPlastiQ® is also included in the blend, ensure that the overall blend meets home compostability requirements. In one embodiment, the blend of the present invention includes a first polyester plastic material (e.g., PBAT) having a first modulus of elasticity and a second polyester (e.g., including PLA), where the first polyester plastic material has a lower modulus (and/or higher flexibility) than the second polyester (e.g., PLA). The blend also includes a carbohydrate-based polymer material.

Similarly, while primarily described in the context of PLA as a component added to a blend to enhance stiffness, it will be understood that other polyester-based polymer materials may alternatively or additionally be used in place of, for example, PLA. For example, PHA may have a high stiffness similar to PLA and may be used to enhance the stiffness of PBAT, PBS, or PCL (all of which typically include low stiffness). By way of example, PLA may typically have a modulus of elasticity of about 3.5-4.0 GPa. PHA may typically have a modulus of elasticity of about 3-3.5 GPa. Both of these materials may exhibit relatively low elongation-to-break values (e.g., about 200% or less for each, with PHA typically 100% or less). PBAT, PBS, and PCL typically exhibit much higher elongation-to-break values (e.g., about 500-800%), but have relatively low moduli (e.g., less than 1 GPa, often less than 0.5 GPa). Therefore, the present invention contemplates blending one of a low stiffness (i.e., low modulus) material exhibiting high elongation at break (e.g., PBAT, PCL, PBS, etc.) with one of a polyester material exhibiting high stiffness (high modulus) and low elongation at break in combination with a carbohydrate-based polymer material, such that the overall blend meets home compostability requirements.

It should be understood that the embodiments of the inventive features disclosed herein are illustrative of the principles of the inventive features. Other variations that may be employed are within the scope of the inventive features. Thus, by way of example, but not limitation, alternative configurations of the inventive features may be utilized in accordance with the teachings herein, for example, at least as described in the preceding paragraphs.

Claims (22)

A polyester-containing plastic material, the polyester-containing plastic material comprising:
a first polyester plastic material having a first modulus comprising polybutylene adipate terephthalate (PBAT) ;
a second polyester plastic material comprising polylactic acid (PLA);
a blend of a carbohydrate-based polymeric material formed by chemically , mechanically, or physically modifying starch and a plasticizer ;
the plasticizer is selected from glycerin and sorbitol;
the first polyester plastic material has a modulus of elasticity lower than the modulus of elasticity of the PLA;
the PLA allows the blend to achieve a higher modulus than the first polyester plastic material alone;
The carbohydrate-based polymer material (1 ) has a crystallinity of less than 20% and is resistant to recrystallization; ( 2 ) has a moisture content of 2% by weight or less; and ( 3 ) does not exhibit an islands-in-a-sea structure when blended with the first polyester plastic material and the second polyester plastic material ;
A polyester-containing plastic material, wherein at least 90% by weight of said polyester-containing plastic material is home compostable at 28°C within 365 days. The material of claim 1, wherein the polyester-containing plastic material is substantially free of any compatibilizer. The material of claim 1, wherein the carbohydrate-based polymer material is present in an amount of 10% to 60% by weight of the blend. The material described in claim 1, wherein the carbohydrate-based polymer material is present in an amount of 30% to 60% by weight of the blend. The material of claim 1, wherein the PLA is present in an amount of at least 5% by weight of the blend. The material of claim 1, wherein the PLA is present in an amount of up to 20% by weight of the blend. The material of claim 1, wherein the PLA is present in an amount of up to 15% by weight of the blend. 10. The material of claim 1, wherein the PBAT is present in an amount of at least 30% by weight of the blend. 10. The material of claim 1, wherein the PBAT is present in an amount of 30% to 70% by weight of the blend. The material of claim 1, wherein the PLA exhibits compostability at 28°C in the blend, whereas the PLA exhibits reduced compostability at 28°C within 365 days when tested alone. The material of claim 1, further comprising an inorganic filler within the blend. 12. The material of claim 11 , wherein the inorganic filler comprises calcium carbonate. 12. The material of claim 11 , wherein at least 90% by weight of the polyester-containing plastic material is home compostable within 365 days at 28°C ± 2°C as determined under EN 13432. A polyester-containing plastic material comprising a blend of polybutylene adipate terephthalate (PBAT), polylactic acid (PLA), and a carbohydrate-based polymeric material formed by chemically , mechanically, or physically modifying starch and a plasticizer;
the plasticizer is selected from glycerin and sorbitol;
the PBAT is present in an amount of at least 30% by weight of the blend;
the PLA is in an amount of up to 20% by weight of the blend;
the carbohydrate-based polymeric material comprises 10% to 60% by weight of the blend;
The carbohydrate-based polymer material (1 ) has a crystallinity of less than 20% and is resistant to recrystallization; ( 2 ) has a moisture content of 2% by weight or less; and ( 3 ) does not exhibit an islands-in-a-sea structure when blended with the PBAT and the PLA ;
1. A polyester-containing plastic material, wherein at least 90% by weight of said polyester-containing plastic material is home compostable under EN 13432 at 28°C ± 2°C within 365 days. 15. The material of claim 14 , wherein the carbohydrate-based polymer material is present in an amount of 30% to 60% by weight of the blend. 15. The material of claim 14 , wherein the PLA exhibits compostability at 28°C ± 2°C in the blend, while the PLA alone exhibits reduced compostability at 28°C ± 2°C. 15. The material of claim 14 , wherein the PLA is present in an amount of up to 15% by weight of the blend. 15. The material of claim 14 , wherein the PBAT is present in an amount of 30% to 70% by weight of the blend. 15. The material of claim 14 , further comprising an inorganic filler within the blend. 20. The material of claim 19 , wherein the inorganic filler comprises calcium carbonate and is present at 5% to 30%, or 10% to 30% by weight of the material. The material of claim 1, wherein the plasticizer comprises sorbitol. The material of claim 1, wherein the starch comprises a mixture of two different starches, at least one of which comprises corn starch, potato starch, tapioca starch, or cassava starch.