Multiphase polyhydroxyalkanoate-based compositions and articles made therefrom

Abstract

This specification relates generally to compositions for producing biodegradable, biocompostable, marine degradable, biocompatible articles that contain a bio-based thermoplastic component. In particular, in accordance with the practice of the present invention, it has been discovered that significant improvements in the tensile strength, toughness, and elongation of polyhydroxyalkanoates (PHAs) can be achieved by dispersing amorphous PHA in the PHA and then, optionally, coupling the dispersed amorphous PHA. The polyhydroxyalkanoate / amorphous polyhydroxyalkanoate blends of the present invention contain 70-97.5 wt. % PHA and 2.5-30 wt. % amorphous PHA and can be used to produce a wide array of articles.

Description

[Technical field]

[0001] INCORPORATION BY REFERENCE TO PRIORITY APPLICATIONS All applications for which foreign or domestic priority is claimed that are identified in the Application Data Sheet filed with this application are hereby incorporated by reference under 37 CFR 1.57.

[0002] Technical Field This specification generally relates to compositions of polymer blends of polyhydroxyalkanoates (PHAs). In particular, the invention relates to compositions and articles of manufacture having a continuous phase and a discontinuous phase, the continuous phase being made of poly(3-hydroxybutyrate) homopolymer (PHB) and the discontinuous phase being an amorphous polyhydroxyalkanoate (aPHA) having a glass transition temperature in the range below 20°C and a melting temperature (TM) of 80°C to 180°C. More specifically, the invention relates to a blend of two PHA materials, the continuous phase being between about 88% to 97.5% of the total PHA and the discontinuous phase being between about 2.5% to about 30% of the total PHA. Also described are methods of making the compositions of the invention. The invention also includes articles and films comprising the compositions. [Background technology]

[0003] More plastic was produced in the first decade of this century than all the plastics produced in history up until the year 2000. Although the large-scale use of plastic materials represented a milestone in the history of technological development, the increased use of such materials has led to serious environmental problems. Such materials generally take about 500-1000 years to naturally decompose, meaning that virtually every piece of synthetic plastic ever made exists today in some shape or form. In the case of petroleum-derived plastic resins, it is estimated that approximately 900 billion pounds are produced annually worldwide, a figure that continues to grow at about 4% per year. It is estimated that this annual global production results in approximately 10% or 90 billion pounds entering the Earth's oceans each year, with thousands of seabirds and sea turtles, sea lions, and other marine mammals dying each year from ingesting or becoming entangled in plastic.

[0004] In light of these issues, more than 60 countries have introduced taxes and bans to stop single-use plastics from being discarded, according to the United Nations Environment Agency, an agency of the United Nations. Despite the validity of these facts, the market potential for using these new materials is huge, and biodegradable plastic resins are gaining attention worldwide. Market applications for biodegradable biopolymers include products such as disposable materials (including but not limited to packaging, diapers, tableware, drinkware, and cutlery); cosmetic, agricultural, and water products; and medical and pharmaceutical articles (e.g., controlled release microencapsulated drugs, medical sutures, and bone fracture fixation pins due to their overall biocompatibility and gentle rejection by the recipient organs).

[0005] An important family of biodegradable biopolymers are the polyhydroxyalkanoates (PHAs), which are polyesters naturally synthesized by more than 300 different microorganisms and act as natural energy stores for microorganisms. The simplest and most important member of the family of PHA biopolymers is polyhydroxybutyrate (PHB). The commercial interest in PHB is directly related to its biodegradable and biocompatible features, but also to its thermo-mechanical properties and production costs. In addition, there is growing evidence that PHB, when ingested by animals, can function as a microbial regulator of the gut flora, which can have a positive impact on weight gain, growth rate and overall survival (Y. Duan et al., "Effect of dietary poly-β-hydroxybutyrate (PHB) on growth performance, intestinal health status and body composition of Pacific white shrimp Litopenaeus vannamei," Fish & Shellfish Immunology, 60: 520-528 (2017); and EH Najdegerami et al., "Effects of poly-β-hydroxybutyrate (PHB) on Siberian sturgeon (Acipenser baerii) fingerlings performance and its gastrointestinal tract microbial community," FEMS Microbiol Ecol., 79: 25-33 (2012)).

[0006] These thermoplastic or elastomeric polyesters can be conveniently synthesized by culturing various microorganisms, especially bacteria, with carbon sources, including sugars, alkanes, vegetable oils, organic acids, and alcohols, in aqueous media. Depending on the microorganism, carbon source, nutrients, and culture conditions, PHAs, which are typically stored inside the cells as discrete, amorphous, water-insoluble granules, can be difficult to isolate and purify. Once isolated, PHAs, and especially PHB, further suffer from brittleness due to their semi-crystalline nature and thermal instability. One approach to overcome the inherent brittleness of PHB and strengthen PHB is to use copolymers with low levels of valerate. However, such copolymers exhibit a lower melting point than PHB, thus narrowing the temperature range of application of the composition. Alternatively, it is known to incorporate rubber particles into a brittle thermoplastic matrix to improve the impact properties and toughness of polymers (Amos, JL et al., U.S. Pat. No. 2,694,692 (1954); and Baer et al., U.S. Pat. No. 4,306,040 (1981)). Under suitable conditions and with the use of appropriate compatibilizers, a synergistic effect occurs that can form high impact strength polymer blends for high value durable applications. However, the addition of low modulus (or elastic modulus) rubber particles to a polymer reduces stiffness and strength, and this reduction in stiffness significantly reduces the scratch / mar resistance of the resulting blend. Thus, to overcome this brittleness, high modulus fillers such as clays are also incorporated into the reinforcing blends, which, with optimal processing and chemistry, can regain this lost strength and stiffness.

[0007] Thus, there is a need to improve the durability, toughness and impact strength of PHAs without the use of fillers such as clays and without compromising the potential stiffness, strength, biodegradability and nutritional value of PHAs. Summary of the Invention

[0008] The present invention addresses the need to improve the durability, toughness and impact strength of PHAs without compromising their potential stiffness, strength and biodegradability.

[0009] Additionally, the present invention provides a PHA polymer composite that is relatively inexpensive and easy to manufacture.

[0010] In general, the present invention describes environmentally sustainable compositions useful for the manufacture of polyhydroxyalkanoate-based (or polyhydroxyalkanoate-based) articles. In particular, the present invention relates to an article of manufacture having a continuous phase and a discontinuous phase, where the continuous phase is made of poly(3-hydroxybutyrate) homopolymer (PHB) and the discontinuous phase is an amorphous polyhydroxyalkanoate (PHA).

[0011] The novel blended polyhydroxyalkanoate compositions of the present invention may comprise a mixture of two polymers, (i) PHB and (ii) amorphous polyhydroxyalkanoate (aPHA), in combination with a peroxide and a co-agent. Preferably, the compositions of the present invention are biodegradable and biocompatible and comprise about 88% to about 97.5% by weight PHB and about 2.5% to about 30% by weight aPHA, based on the total PHA.

[0012] The novel blended polyhydroxyalkanoate composition can be produced by any suitable method, using any suitable processing (or processing) sequence.For example, in one embodiment, the method includes the steps of (a) mixing PHA polymer with peroxide and co-crosslinking agent in a molten state to form a homogeneous blend; and (b) cooling the homogeneous blend to form a solid PHB / aPHA polymer composition, which can then be molded into an article.Any suitable polymer processing equipment can be used, for example, an extruder (for example, single screw or twin screw) or an injection molding equipment can be used.The above method can further include other steps, such as stranding, color addition, pelletizing and homogenization.

[0013] In another embodiment, the PHA polymer is in the form of a fine particle size powder, and the composition is blended, mixed and processed by dry blending in a predetermined ratio.As above, any suitable processing equipment can be used, for example, an extruder (for example, single screw or twin screw).The above method can further include other steps, such as stranding, color addition, pelletizing and homogenizing the polyhydroxyalkanoate / amorphous polyhydroxyalkanoate blend.

[0014] The novel blended polyhydroxyalkanoate compositions of the present invention can be formed into commercially useful articles, such as, but not limited to, films, sheets, multi-layer structures, fibers, monofilaments, sheets, thermoformed articles, blow molded articles, injection molded articles, and injection stretch blow molded articles. Also provided herein are articles made from any of the blended compositions of the present invention.

[0015] Optionally, additives may be added to the novel blended composition. Such additives may be mixed at appropriate times during the processing of the composition to mold the blended composition. One or more additives may be included in the blended composition to impart one or more selected functional characteristics to the blended composition and any molded articles made therefrom. Examples of additives that may be included in the present invention include heat stabilizers, processing stabilizers, light stabilizers, antioxidants, slip / antiblock agents, pigments, UV absorbers, fillers, lubricants, pigments, dyes, colorants, flow promoters, plasticizers, processing aids, branching agents, reinforcing agents, nucleating agents (described in more detail below), talc, wax, calcium carbonate, radical scavengers, or a combination of one or more of the above functional additives.

[0016] When the manufactured articles formed enter the environment as waste, they can then be broken down into monomeric units (PHAs do not break down into short chain fatty acids, which have been shown to be beneficial for growth performance, intestinal digestion and immune function).

[0017] Additional aspects and features will be set forth in the description which follows, and in part will become apparent to those skilled in the art upon examination of the specification or may be learned by practice of the disclosed aspects. The features and advantages of the disclosed aspects may be realized and attained by means of the instrumentalities, combinations and methods described herein. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0018] This specification relates to compositions for producing biodegradable, biocompostable, marine degradable, biocompatible articles containing bio-based thermoplastic components. In particular, in accordance with the practice of the present invention, it has been found that significant improvements in the toughness and elongation of polyhydroxyalkanoates (PHAs) can be achieved by dispersing an amorphous polyhydroxyalkanoate (aPHA) having a glass transition temperature of less than 20°C in a PHA (more specifically, PHB) and then, optionally, coupling two PHA molecules. The polyhydroxyalkanoate blend of the present invention comprises a continuous phase made of poly(3-hydroxybutyrate) homopolymer (PHB) and a discontinuous phase made of an amorphous polyhydroxyalkanoate (aPHA) having a glass transition temperature of less than 20°C and a melting temperature (TM) of 80°C to 180°C. More specifically, the present invention relates to a blend of two PHA materials, where the continuous phase (PHA) is about 88% to 97.5% of the total PHA, and the discontinuous phase (aPHA) is about 2.5% to about 30% of the total PHA, and peroxides and co-crosslinkers can be added to the blend to enhance the toughness of the blend.

[0019] The two polymers, PHA and aPHA, used to form the blended polyhydroxyalkanoate compositions of the present invention are described in more detail below and may include homopolymers, copolymers and blends thereof. Suitable compatibilizers of the present invention include, but are not limited to, polypropylene co-acrylic acid, polypropylene-g-maleic anhydride, polyethylene-g-maleic anhydride, polyethylene-g-maleic anhydride-co-ethyl acrylate, polyethylene-g-maleic anhydride-co-methyl acrylate, polyethylene-co-butylene / styrene, polyethylene-co-butylene / succinic anhydride, polyethylene-co-acrylic acid, polyethylene-co-methyl acrylate, polyurethanes, thermoplastic polyurethanes, thermoplastic polyesters, thermoplastic polyethers, thermoplastic polyethers. esters, thermoplastic polyols / copolyols polyethylene-co-butyl acrylate, thermoplastic polycaprolactone, polybasic acids, polyglycols, substituted fatty acids, polyester adipates, succinic polyesters, polyoxyalkylenes, polypropylene adipates, glutaric polyesters, polyethylene glycol monooleates, trimethyl citrate, epoxidized soybean oil, acetyl tri-n-butyl citrate, sebacic polyesters, neopentyl glycol-adipic acid-caprolactone, trifunctional polyester adipates, epoxidized linseed oil, castor oil, and glutaric polyesters, which may form blended compositions having two discontinuous phases. Surprisingly, the inventors have found that multiphase block copolymers can uniquely aid in the miscibility of aPHAs and PHA polymers, thus forming blended compositions useful for the manufacture of biodegradable, marine degradable and biocompostable articles with suitable strength and durability. An additional advantage of the blended polyhydroxyalkanoate / amorphous PHA composition is that it is biodegradable, marine degradable, biocompostable, and biocompatible.The blended composition as an article of manufacture may eventually degrade in the environment releasing natural PHA polymer residues (such as, but not limited to, poly-3-hydroxybutyrate (PHB)) which then degrade into water-soluble short chain fatty acid monomers that have been shown to be favorable for growth performance, intestinal digestion and immune function in animal studies.

[0020] The mechanism for this polymer-polymer interface miscibility is believed to be an increase in the intermolecular forces between the polymer chains, which reduces the interfacial tension and creates the desired phase morphology. Without intending to be bound by any particular theory, factors that may affect miscibility include molecular weight, molecular weight distribution, hydrogen bonding, van der Waals forces, dielectric constant, chain polarity (dipole moment), end groups, and polymer purity. The multiphase block copolymer is believed to reduce the interfacial tension between the PHA polymer and the amorphous polyhydroxyalkanoate.

[0021] The novel blended compositions disclosed herein include (a) about 68% to about 97.5% by weight PHA and (b) about 2.5% to about 32% by weight amorphous PHA. It has been discovered that the desired properties can be fine-tuned by varying the concentrations of the components. For example, a formulation having about 68% to about 97.5% by weight PHA and (b) about 2.5% to about 32% by weight aPHA has good mechanical properties for cutlery. Cutlery products generally require increased stiffness, strength, stability, color capability, ease of processing, moldability, disposability, marine degradability, biodegradability, and biocompostability. Where more durable parts are desired for manufacturing parts, such as for electrical, electronic and computer component applications, formulations are prepared having about 68% to about 97.5% by weight PHA and about 2.5% to about 32% by weight aPHA, more preferably 86% to about 96.5% by weight PHA and about 2.5% to about 10% by weight aPHA. Optionally, additives, such as, but not limited to, colorants, nucleating agents, stabilizers, coupling agents, free radical initiators, and reinforcing agents, may be added to the blended compositions of the present invention. Contemplated additives are described in more detail below.

[0022] Throughout this specification, when PHA is referred to, such term should be understood to mean homopolymers, copolymers and blends thereof, which may or may not be food grade. As used herein, the terms "functional properties" and "functional characteristics" should have their ordinary meaning and refer to the specifications, characteristics, qualities, properties or attributes of PHA. PHA functional characteristics include, but are not limited to, molecular weight, polydispersity and / or polydispersity index, melt flow and / or melt index, monomer composition, copolymer structure, melt index, non-PHA material concentration, purity, impact strength, density, specific viscosity, viscous resistance, acid resistance, mechanical shear strength, flexural modulus, elongation at break, freeze-thaw stability, processing condition tolerance, shelf life / stability, hygroscopicity, and color. As used herein, the term "polydispersity index" (or PDI) should be taken as its ordinary meaning and should be considered as a measure of the distribution of molecular masses of a given polymer sample (calculated by dividing the weight average molecular weight by the number average molecular weight). Fully amorphous PHAs (having 0% crystallinity and no observed melting point temperature) and PHAs in the nearly amorphous phase include polymers of 4-hydroxybutyrate, 3-hydroxyhexanoate, 5-hydroxyvalerate, 3-hydroxyhexanoate, 3-hydroxyoctanoate, or other 3-hydroxyalkanoic acids with higher carbon numbers as pendant groups (including those derived from fatty acids), as well as mixtures thereof. The resulting PHAs can be blends, copolymers, mixtures, or combinations of one, two, or more PHA components. While not intending to be limited to a particular theory, the inventors theorize that when aPHA polymers are blended with other polymers, the aPHA polymers readily form separate, discontinuous phases that impart an enhancing effect to the overall polymer blend.

[0023] Polyhydroxyalkanoates are bio- (or biological) polyesters synthesized by a wide range of natural and genetically engineered microorganisms and microbial enzymes, as well as genetically engineered plant crops (Braunegg et al., J. Biotechnology, 65:127-161 (1998); Madison and Huisman, Microbiology and Molecular Biology Reviews, 63:21-53 (1999); Poirier, Progress in Lipid Research, 41:131-155 (2002)). These polymers are biodegradable thermoplastic materials that can be produced from renewable resources and have the potential for use in a wide range of industrial applications (Williams & Peoples, CHEMTECH, 26:38-44 (1996)). Microbial strains useful for producing PHA include Alcaligenes eutrophus (renamed Ralstonia eutropha), Alcaligenes latus, Azotobacter, Aeromonas, Comamonas, Pseudomonad and genetically engineered organisms including genetically engineered bacteria such as Pseudomonas, Ralstonia and Escherichia coli.

[0024] Generally, PHAs are formed by enzymatic polymerization of one or more monomer units. Over 100 different types of monomers have been incorporated into PHA polymers (Steinbuchel and Valentin, FEMS Microbiol. Lett., 128:219-228 (1995)). Examples of monomer units that may be incorporated into PHA include 2-hydroxybutyrate, lactic acid, glycolic acid, 3-hydroxybutyrate (hereinafter referred to as 3HB), 3-hydroxypropionate (hereinafter referred to as 3HP), 3-hydroxyvalerate (hereinafter referred to as 3HV), 3-hydroxyhexanoate (hereinafter referred to as 3HH), 3-hydroxyheptanoate (hereinafter referred to as 3HHep), 3-hydroxyoctanoate (hereinafter referred to as 3HV), and 3-hydroxybutanoate (hereinafter referred to as 3HV). 3-hydroxyacid monomers include (D) or (R) 3-hydroxyacid isomers (except for 3HP, which has no chiral center).

[0025] The terms "PHA", "PHA (or PHAs) (PHAs)" and "polyhydroxyalkanoate" as used herein shall have their ordinary meaning and include, but are not limited to, polymers produced by microorganisms or microbial enzymes; biodegradable and / or biocompatible polymers that can be used as alternatives to petroleum-based plastics such as polypropylene, polyethylene and polystyrene; polymers produced by bacterial fermentation of sugars, lipids or gases; thermoplastic or elastomeric materials derived from microorganisms or microbial-derived enzymes; and / or polymers produced by chemical reactions not within the cell wall of a microorganism. PHAs include, but are not limited to, polyhydroxybutyrate (PHB), polyhydroxyvalerate (PHV), polyhydroxybutyrate-covalerate (PHBV), polyhydroxyhexanoate (PHHx) and blends thereof as described in detail below, as well as short chain length (SCL), medium chain length (MCL) and long chain length (LCL) PHAs.

[0026] In some embodiments, PHA is a homopolymer (all monomer units are the same). Examples of PHA homopolymers include poly 3-hydroxyalkanoates (e.g., poly 3-hydroxypropionate (hereinafter referred to as P3HP), poly 3-hydroxybutyrate (hereinafter referred to as PHB) and poly 3-hydroxyvalerate), poly 4-hydroxyalkanoates (e.g., poly 4-hydroxybutyrate (hereinafter referred to as P4HB) or poly 4-hydroxyvalerate (hereinafter referred to as P4HV)), and poly 5-hydroxyalkanoates (e.g., poly 5-hydroxyvalerate (hereinafter referred to as P5HV)).

[0027] In some embodiments, the starting PHA is a copolymer (comprising two or more different monomer units) with different monomers randomly distributed in the polymer chain. Examples of PHA copolymers include poly 3-hydroxybutyrate-co-3-hydroxypropionate (hereinafter referred to as PHB3HP), poly 3-hydroxybutyrate-co-4-hydroxybutyrate (hereinafter referred to as PHB4HB), poly 3-hydroxybutyrate-co-4-hydroxyvalerate (hereinafter referred to as PHB4HV), poly 3-hydroxybutyrate-co-3-hydroxyvalerate (hereinafter referred to as PHB3HV), poly 3-hydroxybutyrate-co-3-hydroxyhexanoate (hereinafter referred to as PHB3HH), and poly 3-hydroxybutyrate-co-5-hydroxyvalerate (hereinafter referred to as PHB5HV).

[0028] By selecting monomer type and controlling the ratio of monomer units in a given PHA copolymer, a wide range of material properties can be achieved. Although an example of a PHA copolymer having two different monomer units is provided, the PHA can have more than two different monomer units (e.g., three different monomer units, four different monomer units, five different monomer units, six different monomer units, etc.). An example of a PHA having four different monomer units is PHB-co-3HH-co-3HO-co-3HD or PHB-co-3HO-co-3HD-co-3HDd (hereinafter, these types of PHA copolymers are referred to as PHB3HX). Typically, when PHB3HX has three or more monomer units, 3HB monomers are at least 70% by weight of the total monomers, preferably 85% by weight of the total monomers, and most preferably greater than 90% by weight of the total monomers, for example 92%, 93%, 94%, 95%, 96% by weight of the copolymer, and HX comprises one or more monomers selected from 3HH, 3HO, 3HD, 3HDd.

[0029] Homopolymer (all monomer units are identical) PHB and 3-hydroxybutyrate copolymers (PHB3HP, PHB4HB, PHB3HV, PHB4HV, PHB5HV, PHB3HHP, hereafter referred to as PHB copolymers) containing 3-hydroxybutyrate and at least one other monomer are of particular interest in terms of commercial manufacture and applications. It is useful to describe these copolymers with reference to their material properties as shown below. Type 1 PHB copolymers typically have a glass transition temperature (Tg) in the range of 6°C to -10°C and a melting temperature Tm between 80°C and 180°C. Type 2 PHB copolymers are typically based on or are blends of PHB4HB and PHB5HV polymers with a Tg of -20°C to -50°C and a Tm of 55°C to 90°C and with a 4HB, SHV, 6HH content of more than 15%. In certain embodiments, the Type 2 copolymer has a phase component that has a Tg between -15°C and -45°C and no Tm.

[0030] When used in the present invention, the molecular weight of the PHA is between about 5,000,000 and about 2,500,000 daltons, between about 2,500,000 and about 1,000,000 daltons, between about 1,000,000 and about 750,000 daltons, between about 750,000 and about 500,000 daltons, between about 500,000 and about 250,000 daltons, between about 250,000 and about 100,000 daltons, between about 100,000 and about 50,000 daltons, between about 50,000 and about 10,000 daltons, and overlapping ranges thereof.

[0031] In measuring the molecular weight, techniques such as gel permeation chromatography (GPC) can be used. In this method, polystyrene standards are utilized. The PHA can have a polystyrene equivalent weight average molecular weight (in Daltons) of at least 500, at least 10,000 or at least 50,000 and / or less than 2,000,000, less than 1,000,000, less than 1,500,000, and less than 800,000. In one embodiment, the PHA generally has a weight average molecular weight in the range of 100,000 to 700,000. For example, the molecular weight range for the PHB and type 1 PHB copolymer used in the present application is in the range of 200,000 Daltons to 1.5 million Daltons, as measured by the GPC method, and the molecular weight range for the type 2 PHB copolymer used in the present application is in the range of 20,000 to 1.5 million Daltons.

[0032] In certain embodiments, the branched PHAs (described in more detail below) have a linear equivalent weight average molecular weight of about 150,000 Daltons to about 500,000 Daltons, and a polydispersity index of about 1.0 to about 8.0. As used herein, weight average molecular weight and linear equivalent weight average molecular weight are measured by gel permeation chromatography, for example, using chloroform as both the eluent and diluent for the PHA samples. Calibration curves for measuring molecular weight are obtained using linear polystyrene as molecular weight standards and the "log MW vs. elution volume" calibration method.

[0033] The PHA used in the methods, compositions and pellets described in the present invention is selected from: PHA; a PHA blend of PHB and a type 1 PHB copolymer, wherein the PHB content by weight of the PHA in the PHA blend is in the range of 20% to 99% by weight of the PHA in the PHA blend; a PHA blend of PHB and a type 2 PHB copolymer, wherein the PHB content by weight of the PHA in the PHA blend is in the range of 20% to 99% by weight of the PHA in the PHA blend; a PHA blend of a type 1 PHB copolymer and a different type 1 PHB copolymer, wherein the content of the first type 1 copolymer is in the range of 20% to 99% by weight of the PHA in the PHA blend; a PHA blend of a type 1 PHB copolymer and a type 2 PHB copolymer, wherein the type 1 PHB copolymer content is in the range of 20% to 99% by weight of the PHA in the PHA blend; a PHA blend of a type 1 PHB copolymer and a type 2 PHB copolymer, wherein the PHB content is in the range of 20% to 99% by weight of the PHA in the PHA blend, the type 1 PHB copolymer content is in the range of 20% to 99% by weight of the PHA in the PHA blend, and the type 2 PHB copolymer content is in the range of 20% to 99% by weight of the PHA in the PHA blend.

[0034] The PHA blend of PHB and Type 1 PHB copolymer is a blend of PHB and PHB3HP, wherein the PHB content in the PHA blend is in the range of 20% to 99% by weight of the PHA in the PHA blend, and the 3HP content in the PHB3HP is in the range of 7% to 15% by weight of the PHB3HP.

[0035] The PHA blend of PHB and Type 1 PHB copolymer is a blend of PHB and PHB3HV, wherein the PHB content of the PHA blend is in the range of 20% to 99% by weight of the PHA in the PHA blend, and the 3HV content in the PHB3HV is in the range of 4% to 22% by weight of the PHB3HV.

[0036] A PHA blend of PHB and Type 1 PHB copolymer is a blend of PHB and PHB4HB, wherein the PHB content of the PHA blend is in the range of 20% to 99% by weight of the PHA in the PHA blend, and the 4HB content in the PHB4HB is in the range of 4% to 15% by weight of the PHB4HB.

[0037] The PHA blend of PHB and Type 1 PHB copolymer is a blend of PHB and PHB4HV, wherein the PHB content of the PHA blend is in the range of 20% to 99% by weight of the PHA in the PHA blend, and the 4HV content in the PHB4HV is in the range of 4% to 15% by weight of the PHB4HV.

[0038] The PHA blend of PHB and Type 1 PHB copolymer is a blend of PHB and PHB5HV, wherein the PHB content of the PHA blend is in the range of 20% to 90% by weight of the PHA in the PHA blend, and the 5HV content in the PHB5HV is in the range of 4% to 15% by weight of the PHB5HV.

[0039] A PHA blend of PHB and Type 1 PHB copolymer is a blend of PHB and PHB3HH, wherein the PHB content of the PHA blend is in the range of 20% to 90% by weight of the PHA in the PHA blend, and the 3HH content in the PHB3HH is in the range of 4% to 15% by weight of the PHB3HH.

[0040] The PHA blend of PHB and Type 1 PHB copolymer is a blend of PHB and PHB3HX, wherein the PHB content of the PHA blend is in the range of 20% to 90% by weight of the PHA in the PHA blend, and the 3HX content in the PHB3HX is in the range of 4% to 15% by weight of the PHB3HX.

[0041] The PHA blend is a blend of a type 1 PHB copolymer selected from the group consisting of PHB3HV, PHB3HP, PHB4HB, PHBV, PHV4HV, PHB5HV, PHB3HH and PHB3HX, and a second type 1 PHB copolymer different from the first type 1 PHB copolymer and selected from the group consisting of PHB3HV, PHB3HP, PHB4HB, PHBV, PHV4HV, PHB5HV, PHB3HH and PHB3HX, wherein the content of the first type 1 PHB copolymer in the PHA blend is in the range of 20% by weight to 99% by weight of the total PHA in the PHA blend.

[0042] A PHA blend of PHB and type 2 PHB copolymer is a blend of PHB and PHB4HB, wherein the PHB content in the PHA blend is in the range of 20% to 99% by weight of the PHA in the PHA blend, and the 4HB content in the PHB4HB is in the range of 20% to 60% by weight of the PHB4HB.

[0043] The PHA blend of PHB and type 2 PHB copolymer is a blend of PHB and PHB5HV, wherein the PHB content in the PHA blend is in the range of 20% to 99% by weight of the PHA in the PHA blend, and the 5HV content in the PHB5HV is in the range of 20% to 60% by weight of the PHB5HV.

[0044] The PHA blend of PHB and type 2 PHB copolymer is a blend of PHB and PHB3HH, where the PHB content in the PHA blend is in the range of 20% to 99% by weight of the PHA in the PHA blend, and the 3HH content in the PHB3HH is in the range of 35% to 90% by weight of PHB3HX.

[0045] The PHA blend of PHB and type 2 PHB copolymer is a blend of PHB and PHB3HX, wherein the PHB content in the PHA blend is in the range of 20% to 99% by weight of the PHA in the PHA blend, and the 3HX content in the PHB3HX is in the range of 35% to 90% by weight of the PHB3HX.

[0046] The PHA blend is a blend of PHB and a type 1 PHB copolymer and a type 2 PHB copolymer, wherein the PHB content in the PHA blend is in the range of 20% to 99% by weight of the PHA in the PHA blend, the type 1 PHB copolymer content in the PHA blend is in the range of 20% to 99% by weight of the PHA in the PHA blend, and the type 2 PHB copolymer content in the PHA blend is in the range of 20% to 99% by weight of the PHA in the PHA blend.

[0047] For example, the PHA blend may have a PHB content in the PHA blend ranging from 20% to 99% by weight of the PHA in the PHA blend, a PHB3HV content in the PHA blend ranging from 20% to 99% by weight of the PHA in the PHA blend (the 3HV content in the PHB3HV is in the range of 3% to 22% by weight of PHB3HV), and a PHBHX content in the PHA blend ranging from 20% to 99% by weight of the PHA in the PHA blend (the 3HX content in the PHBHX is in the range of 35% to 90% by weight of PHBHX).

[0048] For example, the PHA blend may have a PHB content in the PHA blend ranging from 20% to 99% by weight of the PHA in the PHA blend, a PHB3HV content in the PHA blend ranging from 20% to 99% by weight of the PHA in the PHA blend (the 3HV content in the PHB3HV ranging from 3% to 22% by weight of PHB3HV), and a PHB4HB content in the PHA blend ranging from 20% to 99% by weight of the PHA in the PHA blend (the 4HB content in the PHB4HB ranging from 20% to 60% by weight of PHB4HB).

[0049] For example, the PHA blend may have a PHB content in the PHA blend ranging from 20% to 99% by weight of the PHA in the PHA blend, a PHB3HV content in the PHA blend ranging from 5% to 90% by weight of the PHA in the PHA blend (the 3HV content in the PHB3HV is in the range of 3% to 22% by weight of the PHB3HV), and a PHB5HV content in the PHA blend ranging from 20% to 99% by weight of the PHA in the PHA blend (the 5HV content in the PHB5HV is in the range of 20% to 60% by weight of the PHB5HV).

[0050] For example, the PHA blend may have a PHB content in the PHA blend ranging from 20% to 99% by weight of the PHA in the PHA blend, a PHB4HB content in the PHA blend ranging from 20% to 99% by weight of the PHA in the PHA blend (the 4HB content in the PHB4HB ranges from 4% to 15% by weight of PHB4HB), and a PHB4HB content in the PHA blend ranging from 20% to 99% by weight of the PHA in the PHA blend (the 4HB content in the PHB4HB ranges from 20% to 60% by weight of PHB4HB).

[0051] For example, the PHA blend may have a PHB content in the PHA blend ranging from 20% to 99% by weight of the PHA in the PHA blend, a PHB4HB content in the PHA blend ranging from 20% to 99% by weight of the PHA in the PHA blend (the 4HB content in PHB4HB is in the range of 4% to 15% by weight of PHB4HB), and a PHB5HV content in the PHA blend ranging from 20% to 99% by weight of the PHA in the PHA blend (the 5HV content in PHB5HV is in the range of 30% to 90% by weight of PHB5HV).

[0052] For example, the PHA blend may have a PHB content in the PHA blend ranging from 20% to 99% by weight of the PHA in the PHA blend, a PHB4HB content in the PHA blend ranging from 20% to 99% by weight of the PHA in the PHA blend (the 4HB content in PHB4HB is in the range of 4% to 15% by weight of PHB4HB), and a PHB3HX content in the PHA blend ranging from 20% to 99% by weight of the PHA in the PHA blend (the 3HX content in PHB3HX is in the range of 35% to 90% by weight of PHB3HX).

[0053] For example, the PHA blend may have a PHB content in the PHA blend ranging from 20% to 99% by weight of the PHA in the PHA blend, a PHB4HV content in the PHA blend ranging from 20% to 99% by weight of the PHA in the PHA blend (the 4HV content in the PHB4HV is in the range of 3% to 15% by weight of the PHB4HV), and a PHB5HV content in the PHA blend ranging from 20% to 99% by weight of the PHA in the PHA blend (the 5HV content in the PHB5HV is in the range of 30% to 90% by weight of the PHB5HV).

[0054] For example, the PHA blend may have a PHB content in the PHA blend ranging from 20% to 99% by weight of the PHA in the PHA blend, a PHB3HH content in the PHA blend ranging from 20% to 99% by weight of the PHA in the PHA blend (the 3HH content in PHB3HH is in the range of 3% to 15% by weight of PHB3HH), and a PHB4HB content in the PHA blend ranging from 20% to 99% by weight of the PHA in the PHA blend (the 4HB content in PHB4HB is in the range of 20% to 60% by weight of PHB4HB).

[0055] For example, the PHA blend may have a PHB content in the PHA blend ranging from 20% to 99% by weight of the PHA in the PHA blend, a PHB3HH content in the PHA blend ranging from 20% to 99% by weight of the PHA in the PHA blend (the 3HH content in PHB3HH is in the range of 3% to 15% by weight of PHB3HH), and a PHB5HV content in the PHA blend ranging from 20% to 99% by weight of the PHA in the PHA blend (the 5HV content in PHB5HV is in the range of 20% to 60% by weight of PHB5HV).

[0056] For example, the PHA blend may have a PHB content in the PHA blend ranging from 20% to 99% by weight of the PHA in the PHA blend, a PHB3HH content in the PHA blend ranging from 20% to 99% by weight of the PHA in the PHA blend (the 3HH content in PHB3HH is in the range of 3% to 15% by weight of PHB3HH), and a PHB3HX content in the PHA blend ranging from 20% to 99% by weight of the PHA in the PHA blend (the 3HX content in PHB3HX is in the range of 35% to 90% by weight of PHB3HX).

[0057] For example, the PHA blend may have a PHB content in the PHA blend ranging from 20% to 99% by weight of the PHA in the PHA blend, a PHB3HX content in the PHA blend ranging from 20% to 99% by weight of the PHA in the PHA blend (the 3HX content in the PHB3HX ranging from 3% to 12% by weight of the PHB3HX), and a PHB3HX content in the PHA blend ranging from 20% to 99% by weight of the PHA in the PHA blend (the 3HX content in the PHB3HX ranging from 35% to 90% by weight of the PHB3HX).

[0058] For example, the PHA blend may have a PHB content in the PHA blend ranging from 20% to 99% by weight of the PHA in the PHA blend, a PHB3HX content in the PHA blend ranging from 20% to 99% by weight of the PHA in the PHA blend (the 3HX content in PHB3HX is in the range of 3% to 12% by weight of PHB3HX), and a PHB4HB content in the PHA blend ranging from 20% to 99% by weight of the PHA in the PHA blend (the 4HB content in PHB4HB is in the range of 20% to 60% by weight of PHB4HB).

[0059] For example, the PHA blend may have a PHB content in the PHA blend ranging from 20% to 99% by weight of the PHA in the PHA blend, a PHB3HX content in the PHA blend ranging from 20% to 99% by weight of the PHA in the PHA blend (the 3HX content in PHB3HX is in the range of 3% to 12% by weight of PHB3HX), and a PHB5HV content in the PHA blend ranging from 20% to 99% by weight of the PHA in the PHA blend (the 5HV content in PHB5HV is in the range of 20% to 60% by weight of PHB5HV).

[0060] As mentioned above, the novel blended polyhydroxyalkanoate / amorphous polyhydroxyalkanoate compositions of the present invention comprise a blend of polyhydroxyalkanoate and amorphous polyhydroxyalkanoate. Optionally, additives such as those disclosed below can be used to further modify the desired properties of the blended compositions of the present invention. Additives

[0061] In some embodiments, various additives are added to the novel blended composition. Such additives may be mixed at an appropriate time during the processing of the composition to form the composition. One or more additives are included in the blended composition to impart one or more selected properties to the blended composition and any molded articles made therefrom. Examples of additives that may be included in the present invention include, but are not limited to, heat stabilizers, processing stabilizers, light stabilizers, antioxidants, slip / antiblock agents, pigments, UV absorbers, fillers, lubricants, pigments, dyes, colorants, flow promoters, plasticizers, nucleating agents (described in more detail below), talc, wax, calcium carbonate, radical scavengers, or combinations of one or more of the above functional additives. Branching agents and / or coupling agents are added to make one or more of these more easily incorporated into the polymer. For example, the branching agents and / or coupling agents are mixed with a plasticizer (such as a non-reactive plasticizer, such as a citrate ester) and compounded with the polymer under conditions that induce branching. Examples of suitable fillers include, but are not limited to, glass fibers and minerals such as precipitated calcium carbonate, ground calcium carbonate, talc, wollastonite, alumina trihydrate, wood flour, ground walnut shells, coconut shells, rice husk shells, and the like. In addition, multifunctional coupling agents such as divinylbenzene, triallyl cyanurate, triallyl isocyanurate, urethane di-, tri-, and tetraacrylates and methacrylates can be added. Such coupling agents can be added to one or more of these additives to facilitate incorporation into the polymer. For example, the coupling agent can be mixed with a plasticizer, such as a non-reactive plasticizer, such as a citrate ester, and compounded with the polymer under conditions that induce branching. Other coupling agents useful in the compositions of the present invention, such as the compositions of the first, second, third, or fourth aspects, are hyperbranched or dendritic polyesters, such as dendritic or hyperbranched acrylates, such as urethane acrylates.

[0062] Optionally, the conversion agent is included in the blended composition of the present invention at a concentration of about 0.05 to about 20% by weight of the total composition. For example, the range in one embodiment is about 0.05 to about 5% of the total composition. The additive is any compound known to one skilled in the art to be useful in the manufacture of thermoplastic materials. Exemplary additives include, for example, plasticizers (e.g., to increase the flexibility of the thermoplastic composition), antioxidants (e.g., to protect the thermoplastic composition from degradation by ozone or oxygen), UV stabilizers (e.g., to protect against weathering), lubricants (e.g., to reduce friction), pigments (e.g., to impart color to the thermoplastic composition), flame retardants, fillers, reinforcing agents, mold release agents, and antistatic agents. It is well within the ability of one skilled in the art to determine whether to include additives in the blended composition of the present invention, and if so, which additives and in what amounts to include in the composition.

[0063] The additives may be prepared as a masterbatch, for example by incorporating the additive into a PHA or PHA blend and producing pellets of the resulting composition for addition to subsequent processing. In a masterbatch, the concentration of the additive is higher than the final amount for the product to provide proportional mixing of the additive in the final composition.

[0064] In compositions where the PHA is poly-3-hydroxybutyrate, for example, plasticizers are often used to modify the glass transition temperature and modulus (or elasticity) of the composition, but surfactants can also be used. Lubricants can also be used, for example, in injection molding applications. Thus, plasticizers, surfactants, and lubricants can all be included in the overall composition.

[0065] In other embodiments, the blend includes one or more plasticizers. Examples of plasticizers include phthalates (dimethyl phthalate, diethyl phthalate, dibutyl phthalate, dihexyl phthalate, di-n-octyl phthalate, di-2-ethylhexyl phthalate, diisooctyl phthalate, dicapryl phthalate, dinonyl phthalate, diisononyl phthalate, didecyl phthalate, diundecyl phthalate, dilauryl phthalate, ditridecyl phthalate, dibenzyl phthalate, dicyclohexyl phthalate, butyl benzyl phthalate, octyl decyl phthalate, butyl oct ... phosphate, octyl benzyl phthalate, n-hexyl n-decyl phthalate, n-octyl phthalate, and n-decyl phthalate), phosphate compounds (including but not limited to tricresyl phosphate, trioctyl phosphate, triphenyl phosphate, octyl diphenyl phosphate, cresyl diphenyl phosphate, and trichloroethyl phosphate), adipic acid compounds (including but not limited to dibutoxyethoxyethyl adipate (DBEEA), dioctyl adipate, diisooctyl adipate, di-n-octyl adipate, didecyl adipate, diisodecyl adipate, n-octyl n-decyl adipate, n-heptyl adipate, and n-nonyl adipate), sebacic acid compounds (including but not limited to dibutyl sebacate, dioctyl sebacate, diisooctyl sebacate, and butyl benzyl sebacate), azelaic acid compounds, citric acid compounds (including but not limited to triethyl citrate, acetyl triethyl citrate, tributyl citrate, acetyl tributyl citrate, and acetyl trioctyl citrate), glycolic acid compounds (including, but not limited to, methyl phthalyl ethyl glycolate, ethyl phthalyl ethyl glycolate, and butyl phthalyl ethyl glycolate), trimellitic acid compounds (including, but not limited to, trioctyl trimellitate and tri-n-octyl n-decyl trimellitate), phthalic acid isomer compounds (including, but not limited to, dioctyl isophthalate and dioctyl terephthalate),Ricinoleic acid compounds (including, but not limited to, methyl acetyl ricinoleate and butyl acetyl ricinoleate), polyester compounds (including, but not limited to, reaction products of diols selected from butanediol, ethylene glycol, propane 1,2 diol, propane 1,3 diol; polyethylene glycol; glycerol; dibasic acids selected from adipic acid, succinic acid, succinic anhydride; and hydroxy acids such as hydroxystearic acid), epoxidized soybean oil, chlorinated paraffins, chlorinated fatty acid esters, fatty acid compounds, vegetable oils, pigments, and acrylic acid compounds. The plasticizers may be used alone or in combination with each other.

[0066] In an embodiment, the blended polyhydroxyalkanoate / amorphous polyhydroxyalkanoate composition of the present invention includes one or more surfactants. Surfactants are typically used for dust removal, lubrication, reducing surface tension and / or density. Examples of surfactants include, but are not limited to, mineral oil, castor oil, and soybean oil. One mineral oil surfactant is DRAKEOL® 34 surfactant available from Penreco (Dickinson, Texas, USA). MAXSPERSE® W-6000 surfactant and W-3000 solid surfactant are available from Chemax Polymer Additives (Piedmont, South Carolina, USA). Nonionic surfactants having HLB values ​​ranging from about 2 to about 16 may be used, examples of which are TWEEN-20 surfactant, TWEEN-65 surfactant, Span-40 surfactant, and Span 85 surfactant.

[0067] Anionic surfactants include: aliphatic carboxylic acids, such as, for example, lauric acid, myristic acid, palmitic acid, stearic acid, and oleic acid; fatty acid soaps, such as, for example, the sodium or potassium salts of the above aliphatic carboxylic acids;N-acyl-N-methylglycine salts, N-acyl-N-methyl-beta-alanine salts, N-acylglutamates, polyoxyethylene alkyl ether carboxylates, acylated peptides, alkylbenzenesulfonates, alkylnaphthalenesulfonates, naphthalenesulfonates-formaldehyde polycondensates, melaminesulfonates-formaldehyde polycondensates, dialkylsulfosuccinate salts, alkylsulfosuccinate disalts, polyoxyethylene alkylsulfosuccinate disalts, alkylsulfoacetates, (alpha-olefinsulfonates, N-acylmethyltaurates, dimethyl 5-sulfoisophthalate sodium salts, sulfated oils, higher alcohol sulfates, polyoxyethylene alkyl ether sulfates, secondary high Primary alcohol ethoxy sulfate, polyoxyethylene alkylphenyl ether sulfate, monoglysulfate, sulfate salt of fatty acid alkylolamide, polyoxyethylene alkyl ether phosphate, polyoxyethylene alkylphenyl ether phosphate, alkyl phosphate, alkylamine oxide bistridecyl sodium salt of sulfosuccinate, dioctyl sodium salt of sulfosuccinate, dihexyl sodium salt of sulfosuccinate, dicyclohexyl sodium salt of sulfosuccinate, diamyl sodium salt of sulfosuccinate, diisobutyl sodium salt of sulfosuccinate, alkyl ammine guanidine polyoxyethanol, disodium salt of ethoxylated alcohol half ester of sulfosuccinate sulfosuccinate ethoxylated alcohol half esters, disodium sulfosuccinate ethoxylated nonylphenol half esters, isodecyl sulfosuccinate disodium salt, N-octadecyl sulfosuccinate disodium salt, N-(1,2-dicarboxyethyl)-N-octadecyl sulfosuccinamide tetrasodium salt, mono- or didodecyl diphenyl oxide disulfonic acid disodium salt, sodium diisopropyl naphthalene sulfonate, and neutralized and concentrated from sodium naphthalene sulfonate;

[0068] One or more lubricants may also be added to the compositions and methods of the present invention. Lubricants are typically used to reduce adhesion (or sticking) to hot metal during processing and may include polyethylene combined with metal stearates (e.g., zinc stearate), paraffin oil, and paraffin wax. Other lubricants include stearic acid, amide waxes, ester waxes, metal carboxylates, and carboxylic acids. Lubricants are typically added to the polymer in the range of about 0.1% to about 5% by weight of the compound, typically about 0.7% to about 0.1% by weight. Solid lubricants are warmed to a molten state before or during processing of the blend.

[0069] One or more antimicrobial agents may also be added to the compositions and methods of the present invention. Antimicrobial agents are substances that kill or inhibit the growth of microorganisms, such as bacteria, fungi, protozoa, and viruses. Antimicrobial agents kill (bactericidal) or prevent the growth of microorganisms (microbistatic). A wide range of chemical and natural compounds are used as antimicrobial agents, including, but not limited to: organic acids, essential oils, cations, and elements (e.g., colloidal silver). Commercially available examples include, but are not limited to, PolySept® Z Microorganism, UDA, and AGION®.

[0070] PolySept® Z Microorganisms (available from PolyChem Alloy) are organic salt based non-migratory antimicrobial agents. "UDA" is Urtica dioica agglutinin. AGION® Antimicrobial Agents are silver compounds. AMICAL® 48 Silver is diiodomethyl p-tolylsulfone.

[0071] In the film application of the blended polyhydroxyalkanoate / amorphous polyhydroxyalkanoate compositions and methods described herein, an antiblock masterbatch is also added.A suitable example is a slip antiblock masterbatch mixture of erucamide (20% by weight), diatomaceous earth (15% by weight), nucleant masterbatch (3% by weight), and pelleted into PHA (62% by weight). Branched Polyhydroxyalkanoates

[0072] The term "branched PHA" refers to a PHA having chain branching and / or two or more chain linkages (or couplings). Branching in the side chains is also contemplated. Branching can be achieved in a variety of ways. The PHAs described hereinbefore can be branched with a branching agent by free radical induced coupling of the polymer. In some embodiments, the PHA is branched before being combined in the process. In other embodiments, the PHA is reacted with a peroxide in the process of the present invention. Branching can increase the melt strength of the polymer and impart greater compatibility to the polymeric components of the formulation. The PHA can be branched in any of the ways described in U.S. Patent Nos. 6,620,869, 7,208,535, 6,201,083, 6,156,852, 6,248,862, 6,201,083, and 6,096,810, all of which are incorporated herein by reference in their entirety.

[0073] The polymers of the present invention may be branched according to any of the methods disclosed in International Publication No. WO 2010 / 008447, entitled "Methods For Branching PHA Using Thermolysis," or International Publication No. WO 2010 / 008445, entitled "Branched PHA Compositions, Methods for Their Production, and Use in Applications," both of which were published in English on January 21, 2010 and designate the United States, and which are hereby incorporated by reference in their entireties. Branching Agent

[0074] Branching agents (also referred to as free radical initiators) used in the compositions and methods described herein include organic peroxides. Peroxides are reactive molecules that can react with linear or pre-branched PHA molecules by removing hydrogen atoms from the polymer backbone, leaving behind radicals. PHA molecules with such radicals in their backbone are free to bond with each other to produce branched PHA molecules. Branching agents are selected from suitable initiators known in the art, such as peroxides, azo derivatives (e.g., azonitrile), peresters, peroxycarbonates, and the like. Suitable peroxides for use in the present invention include organic peroxides, such as dialkyl organic peroxides, such as 2,5-dimethyl-2,5-di(t-butylperoxy)hexane, 2,5-bis(t-butylperoxy)-2,5-dimethylhexane (TRIGANOX from Akzo Nobel), and the like. 101), 2,5-dimethyl-di(t-butylperoxy)hexyne-3, di-t-butyl peroxide, dicumyl peroxide, benzoyl peroxide, di-t-amyl peroxide, t-amylperoxy-2-ethylhexyl carbonate (TAEC), t-butylcumyl peroxide, n-butyl-4,4-bis(t-butylperoxy)valerate, 1,1-di(t-butylperoxy)-3,3,5-trimethyl-cyclohexane, 1,1-bis(t-butylperoxy)-3,3,5-trimethylcyclohexane (CPK), 1,1-di(t-butylperoxy)cyclohexane Peroxides that may be used include, but are not limited to, peroxane, 1,1-di(t-amylperoxy)-cyclohexane, 2,2-di(t-butylperoxy)butane, ethyl-3,3-di(t-butylperoxy)butyrate, 2,2-di(t-amylperoxy)propane, ethyl-3,3-di(t-amylperoxy)butyrate, t-butylperoxy-acetate, t-amylperoxyacetate, t-butylperoxybenzoate, t-amylperoxybenzoate, di-t-butyldiperoxyphthalate, di-(tert-butyldiperoxyisopropyl)benzene (VulCup®), and the like. Combinations of peroxides may also be used.Examples of free radical initiators include those mentioned herein, as well as those described, for example, in "Polymer Handbook", 3rd Edition, J. Brandrup & EH Immergut, John Wiley and Sons, 1989, Chapter 2, Irradiation (e.g., e-beam or gamma irradiation) can be used to form PHA branches.

[0075] The efficiency of polymer branching and coupling can also be significantly enhanced by the dispersion of an organic peroxide in a coupling agent, such as a polymerizable (i.e. reactive) plasticizer. The polymerizable plasticizer should have reactive functionality, such as reactive unsaturated double bonds, that increases the overall branching and coupling efficiency.

[0076] As mentioned above, when peroxides decompose, they form very energetic radicals that can abstract hydrogen atoms from the polymer backbone. These radicals have short half-lives, thus limiting the number of branched molecules produced during their active period. Coupling Agent

[0077] The coupling agents (also referred to as co-agents) used in the methods and compositions of the present invention are those that contain two or more reactive functional groups, such as epoxides or double bonds. These coupling agents modify the properties of the polymer, including but not limited to melt strength or toughness. One type of coupling agent is an "epoxy-functional compound." As used herein, "epoxy-functional compound" is intended to include compounds having two or more epoxide groups that can increase the melt strength of polyhydroxyalkanoate polymers by branching, such as by terminal branching as described above.

[0078] When an epoxy-functional compound is used as a coupling agent in the method of the present disclosure, a branching agent is optional. Therefore, one embodiment of the present invention is a method for branching an initial PHA, comprising reacting the initial PHA with an epoxy-functional compound, and further blending the PHA with an amorphous polyhydroxyalkanoate. Alternatively, the present invention is a method for branching an initial polyhydroxyalkanoate polymer, comprising reacting an initial PHA, a branching agent, and an epoxy-functional compound, and further blending the PHA with an amorphous polyhydroxyalkanoate. Alternatively, the present invention is a method for branching an initial polyhydroxyalkanoate polymer, comprising reacting an initial PHA and an epoxy-functional compound in the absence of a branching agent, and further blending the PHA with an amorphous polyhydroxyalkanoate. Such epoxy-functional compounds may include epoxy-functional styrene acrylic polymers (e.g., but not limited to, MP-40 (Kaneka)), acrylic and / or polyolefin copolymers and oligomers with glycidyl groups incorporated as side chains (poly(ethylene-glycidyl methacrylate-co-methacrylate)), and epoxidized oils (e.g., epoxidized soybean oil, olive oil, linseed oil, palm oil, peanut oil, coconut oil, seaweed oil, cod liver oil or mixtures thereof, such as, but not limited to, Merginat® ESBO (Hobum, Hamburg, Germany) and EDENOL® B316 (Cognis, Dusseldorf, Germany)).

[0079] For example, reactive acrylic or functional acrylic coupling agents are used in the branched polymer compositions described herein to increase the molecular weight of the polymer. Such coupling agents are commercially available. One such compound is MP-40 (Kaneka), and another is the Petra line from Honeywell, see, for example, U.S. Pat. No. 5,723,730. Such polymers are often used in plastics recycling (e.g., in polyethylene terephthalate recycling) to increase (or mimic the increase in molecular weight) of the recycled polymer.

[0080] Naturally occurring oils or fatty acid esters with epoxy groups (epoxidized) and / or chemical unsaturation are also used. Examples of naturally occurring oils are olive oil, linseed oil, soybean oil, palm oil, peanut oil, coconut oil, seaweed oil, cod liver oil, or mixtures thereof. Particularly preferred is epoxidized soybean oil (e.g. Merginat® ESBO from Hobum, Hamburg, or EDENOL® B316 from Cognis, Dusseldorf), but others can also be used.

[0081] Another type of coupling agent is one that has two or more double bonds. The coupling agent with two or more double bonds reacts with the double bonds and then couples the PHA. Examples of these include: diallyl phthalate, pentaerythritol urethane acrylate, tetraacrylate, trimethylolpropane triacrylate, pentaerythritol triacrylate, dipentaerythritol pentaacrylate, diethylene glycol dimethacrylate, bis(2-methacryloxyethyl)phosphate.

[0082] In general, compounds having terminal epoxides have been found to perform better than those having epoxide groups located elsewhere in the molecule.

[0083] Compounds with a relatively large number of end groups are most desirable. Molecular weight also plays a role in this regard, with compounds having more end groups relative to their molecular weight (e.g., Joncryl® resins in the range of 3000-4000 g / mol) tending to perform better than compounds having fewer end groups relative to their molecular weight (e.g., Omnova products have molecular weights in the range of 100,000-800,000 g / mol). Nucleating Agent

[0084] For example, a nucleating agent is optionally added to the blended composition to promote its crystallinity. Nucleating agents for various polymers include simple substances, metal compounds including complex oxides, such as carbon black, calcium carbonate, synthetic silicic acids and salts, silica, zinc white, clay, kaolin, basic magnesium carbonate, mica, talc, quartz powder, diatomite, dolomite powder, titanium oxide, zinc oxide, antimony oxide, barium sulfate, calcium sulfate, alumina, calcium silicate, metal salts of organic phosphates, and boron nitride; low molecular weight organic compounds having metal carboxyl groups, such as metal salts of octanoic acid, toluic acid, heptanoic acid, pelargonic acid, lauric acid, myristic acid, palmitic acid, stearic acid, behenic acid, cerotic acid, montanic acid, melissic acid, benzoic acid, p-tert-butylbenzoic acid, terephthalic acid, terephthalic acid monomethyl ester, isophthalic acid, and isophthalic acid monoethyl ester; high molecular weight organic compounds having metal carboxyl groups, such as carboxyl group-containing polyethylene obtained by oxidation of polyethylene; metal salts of carboxyl-containing polypropylene obtained by oxidation of polypropylene; copolymers of olefins (e.g., ethylene, propylene and butane-1) with acrylic or methacrylic acid; copolymers of styrene with acrylic or methacrylic acid; copolymers of olefins with maleic anhydride; and copolymers of styrene with maleic anhydride; high molecular weight organic compounds, such as alpha-olefins branched at the 3-position carbon atom and having less than 5 carbon atoms, for example, 3,3-dimethylbutene-1, 3-methylbutene-1, 3-methylpentene-1, 3-methylhexene-1, and 3,5,5-trimethylhexene-1; polymers of vinylcycloalkanes, such as vinylcyclopentane, vinylcyclohexane, and vinylnorbornene; polyalkylene glycols, such as polyethylene glycol and polypropylene glycol; poly(glycolic acid); cellulose; cellulose esters; and cellulose ethers;Phosphoric or phosphorous acid and its metal salts, such as diphenyl phosphate, diphenyl phosphite, metal salts of bis(4-tert-butylphenyl)phosphate and metal salts of methylene bis-(2,4-tert-butylphenyl)phosphate; sorbitol derivatives, such as bis(p-methylbenzylidene)sorbitol and bis(p-ethylbenzylidene)sorbitol; and thioglycolic anhydride, p-toluenesulfonic acid and its metal salts. The above nucleating agents can be used alone or in combination with each other. In certain embodiments, the nucleating agent is cyanuric acid. In some embodiments, the nucleating agent can also be another polymer (e.g., a polymeric nucleating agent such as PHB).;

[0085] In some embodiments, the nucleating agent is selected from cyanuric acid, carbon black, mica, talc, silica, boron nitride, clay, calcium carbonate, synthetic silicic acids and salts, metal salts of organophosphates, and kaolin. In certain embodiments, the nucleating agent is cyanuric acid.

[0086] In various embodiments, when the nucleating agent is dispersed in a liquid carrier, the liquid carrier is a plasticizer, such as a citric acid compound or an adipic acid compound, such as acetyl citrate tributyrate (CITROFLEX® A4 plasticizer, Vertellus, Inc., High Point, North Carolina), or DBEEA (dibutoxyethoxyethyl adipate), a surfactant, such as Triton X-100 surfactant, TWEEN-20 surfactant, TWEEN-65 surfactant, Span-40 surfactant, or Span 85 surfactant, a lubricant, a volatile liquid, such as chloroform, heptane, or pentane, or an organic liquid or water.

[0087] In other embodiments, the nucleating agent is aluminum hydroxydiphosphate or a compound that includes a nitrogen-containing heteroaromatic core. The nitrogen-containing heteroaromatic core is a pyridine, pyrimidine, pyrazine, pyridazine, triazine, or imidazole.

[0088] In certain embodiments, the nucleating agent comprises aluminum hydroxydiphosphate or a compound that comprises a nitrogen-containing heteroaromatic core. The nitrogen-containing heteroaromatic core is pyridine, pyrimidine, pyrazine, pyridazine, triazine or imidazole. The nucleating agent is as described in U.S. Patent Application Publication No. 2005 / 0209377 by Allen Padwa (incorporated herein in its entirety by reference).

[0089] Other nucleating agents for use in the blended compositions and methods described herein are milled as described in International Publication No. WO 2009 / 129499, entitled "Nucleating Agents for Polyhydroxyalkanoates," published in English, and designating the United States, which is incorporated herein by reference in its entirety. Briefly, the nucleating agent is milled in a liquid carrier until at least 5% of the cumulative solid volume of the nucleating agent is present as particles having a particle size of 5 μm or less. The liquid carrier wet-mills the nucleating agent. In other embodiments, the nucleating agent is milled in a liquid carrier until at least 10% of the cumulative solid volume of the nucleating agent, at least 20%, at least 30%, or at least 40%-50% of the cumulative solid volume of the nucleating agent is present as particles having a particle size of 5 microns or less, 2 microns or less, or 1 micron or less. In other embodiments, the nucleating agent is milled by other methods, such as jet milling. In addition, other methods are utilized to reduce particle size.

[0090] The cumulative solid volume of a particle is the combined volume of the particle in dry form without any other material present. The cumulative solid volume of a particle is measured by measuring the volume of the particle before dispersing the particle in a polymer or liquid carrier, for example by pouring the particle in a dry state into a graduated cylinder or other device suitable for measuring volume. Alternatively, the cumulative solid volume is measured by light scattering.

[0091] Suitable heat stabilizers include, for example, organic phosphites such as triphenyl phosphite, tris-(2,6-dimethylphenyl) phosphite, tris-(mixed mono- and di-nonylphenyl) phosphite, and the like; phosphonates such as dimethylbenzene phosphonate, and the like; phosphates such as trimethyl phosphate, and the like; or combinations comprising at least one of the above heat stabilizers. Heat stabilizers are generally used in amounts of 0.01 to 0.5 parts by weight based on 100 parts by weight of the total composition excluding any fillers.

[0092] Suitable antioxidants include, for example, organic phosphites such as tris(nonylphenyl)phosphite, tris(2,4-di-t-butylphenyl)phosphite, bis(2,4-di-t-butylphenyl)pentaerythritol diphosphite, distearyl pentaerythritol diphosphite, and the like; alkylated monophenols or polyphenols; alkylation reaction products of polyphenols with dienes, such as tetrakis[methylene(3,5-di-tert-butyl-4-hydroxyhydrocinnamate)]methane, and the like; butylation reaction products of para-cresol or dicyclopentadiene; alkylated hydroquinones; hydroxylated thiodiphenyl ethers; alkylidene-bisphenols; benzyl compounds; beta-(3,5-di-tert-butyl-4-hydroxyphenyl)-2,3-dimethylphenyl ethers; esters of beta-(5-tert-butyl-4-hydroxy-3-methylphenyl)-propionic acid with mono- or polyhydrogenated alcohols; esters of thioalkyl or thioaryl compounds, such as distearyl thiopropionate, dilauryl thiopropionate, ditridecyl thiodipropionate, octadecyl-3-(3,5-di-tert-butyl-4-hydroxyphenyl)propionate, pentaerythrityl-tetrakis[3-(3,5-di-tert-butyl-4-hydroxyphenyl)propionate, and the like; amides of beta-(3,5-di-tert-butyl-4-hydroxyphenyl)-propionic acid, and the like, or combinations comprising at least one of the above antioxidants. Antioxidants are generally used in amounts of 0.01 to 0.5 parts by weight based on 100 parts by weight of the total composition excluding all fillers.

[0093] Suitable light stabilizers include, for example, benzotriazoles, such as 2-(2-hydroxy-5-methylphenyl)benzotriazole, 2-(2-hydroxy-5-tert-octylphenyl)-benzotriazole, and 2-hydroxy-4-n-octoxybenzophenone, or combinations comprising at least one of the above light stabilizers. Light stabilizers are generally used in amounts of 0.1 to 1.0 parts by weight based on 100 parts by weight of the total composition excluding any fillers.

[0094] Suitable antistatic agents include, for example, glycerol monostearate, sodium stearyl sulfonate, sodium dodecylbenzene sulfonate, and the like, or combinations of the above antistatic agents. In one embodiment, carbon fibers, carbon nanofibers, carbon nanotubes, carbon black, or any combination of the above, may be used in polymer resins containing chemical antistatic agents to render the composition electrostatically dissipative.

[0095] Suitable release agents include, for example, metal stearates, stearyl stearate, pentaerythritol tetrastearate, beeswax, montan wax, paraffin wax, and the like, or a combination comprising at least one of the foregoing release agents. Release agents are generally used in an amount of 0.1 to 1.0 parts by weight per 100 parts by weight of the total composition excluding any fillers.

[0096] Suitable UV absorbers include, for example, hydroxybenzophenones; hydroxybenzotriazoles; hydroxybenzotriazines; cyanoacrylates; oxanilides; benzoxazinones; 2-(2H-benzotriazol-2-yl)-4-(1,1,3,3-tetramethylbutyl)-phenol (CYASORB® 5411); 2-hydroxy-4-n-octyloxybenzophenone (CYASORB™ 531); 2-[4,6-bis(2,4-dimethylphenyl)-1,3,5-triazin-2-yl]-5-(octyloxy)-phenol (CYASORB™ 1164); 2,2′-(1,4-phenylene)bis(4H-3,1-benzoxazin-4-one) (CYASORB™ 1164). )UV-3638); 1,3-bis[(2-cyano-3,3-diphenylacryloyl)oxy]-2,2-bis[[(2-cyano-3,3-diphenyl-acryloyl)oxy]methyl]propane (UVINUL® 3030); 2,2'-(1,4-phenylene)bis(4H-3,1-benzoxazin-4-one); 1,3-bis[(2-cyano-3,3-diphenylacryloyl)oxy]-2,2-bis[[(2-cyano-3,3-diphenyl-acryloyl)oxy]methyl]propane; nano-sized inorganic materials, such as titanium oxide, cerium oxide, and zinc oxide, all having particle sizes less than 100 nanometers; and the like, or combinations comprising at least one of the above UV absorbers. UV absorbers are generally used in amounts of 0.01 to 3.0 parts by weight based on 100 parts by weight of the total composition excluding any fillers.

[0097] Suitable pigments include, for example, inorganic pigments such as metal oxides and mixed metal oxides, such as zinc oxide, titanium dioxide, iron oxide, and the like; sulfides, such as zinc sulfide, and the like; aluminates; sodium sulfo-silicates; sulfo-silicate); sulfates and chromates; carbon black; zinc ferrite; ultramarine blue; Pigment Brown 24; Pigment Red 101; Pigment Yellow 119; organic pigments such as azo, diazo, quinacridone, perylene, naphthalene, tetracarboxylic acid, flavanthrone, isoindolinone, tetrachloroisoindolinone, anthraquinone, anthanthrone, dioxazine, phthalocyanine, and azo lakes; Pigment Blue 60, Pigment Red 122, Pigment Red 149, Pigment Red 177, Pigment Red 179, Pigment Red 202, Pigment Violet 29, Pigment Blue 15, Pigment Green 7, Pigment Yellow 147, and Pigment Yellow 150, or combinations comprising at least one of the above pigments. Pigments are generally used in amounts of 1 to 10 parts by weight based on 100 parts by weight of the entire composition excluding any fillers.

[0098] Suitable dyes include, for example, organic dyes such as Coumarin 460 (blue), Coumarin 6 (green), Nile Red, etc.; lanthanide complexes; hydrocarbon and substituted hydrocarbon dyes; polycyclic aromatic hydrocarbons; scintillation dyes (preferably oxazoles and oxadiazoles); aryl- or heteroaryl-substituted poly(2-8 olefins); carbocyanine dyes; phthalocyanine dyes and pigments; oxazine dyes; carbostyril dyes; porphyrin dyes; acridine dyes; anthraquinone dyes; arylmethane dyes; azo dyes; diazonium dyes; thiazole dyes; perylene dyes, perinone dyes; bis-benzoxazolylthiophene (BBOT); and xanthene dyes; fluorophores, such as anti-Stokes shift dyes that absorb in the near infrared wavelengths and emit in the visible wavelengths; luminescent dyes, such as 5-amino-9-diethyliminobenzo(a)phenoxazonium perchlorate; 7-amino-4-methylcarbostyril; 7-amino-4-methylcoumarin; 3-(2'-benzimidazolyl)-7-N,N-diethylaminocoumarin; 3-(2'-Benzothiazolyl)-7-diethylaminocoumarin;2-(4-biphenyl)-5-(4-t-butylphenyl)-1,3,4-oxadiazole;2-(4-biphenyl)-6-phenylbenzoxazole-1,3;2,5-bis-(4-biphenyl)-1)-1,3,4-oxadiazole;2,5-bis-(4-biphenyl)-oxazole;4,4'-bis-(2-butyloctyloxy)-p-quaterphenyl;p-bis(o-methylstyryl)-benzene;5,9-diaminobenzo(a)phenoxazonium perchlorate; 4-Dicyanomethylene-2-methyl-6-(p-dimethylaminostyryl)-4H-pyran;1,1'-Diethyl-2,2'-carbocyanine iodide;3,3'-Diethyl-4,4',5,5'-dibenzothiatricarbocyanine iodide;7-Diethylamino-4-methylcoumarin;7-Diethylamino-4-trifluoromethylcoumarin;2,2'-Dimethyl-p-quaterphenyl;2,2-Dimethyl-p-terphenyl;7-Ethylamino-6-methyl-4-trifluoromethylcoumarin;7-Ethylamino-4-trifluoromethylcoumarin;Nile red; rhodamine 700; oxazine 750; rhodamine 800; IR 125; IR 144; IR 140; IR 132; IR 26; IRS; diphenylhexatriene; diphenylbutadiene; tetraphenylbutadiene; naphthalene; anthracene; 9,10-diphenylanthracene; pyrene; chrysene; rubrene; coronene; phenanthrene, and the like, or a combination comprising at least one of the above dyes. The dyes are generally used in an amount of 0.1 to 5 parts by weight based on 100 parts by weight of the total composition excluding all fillers.;

[0099] Suitable colorants include, for example, titanium dioxide, anthraquinones, perylenes, perinones, indanthrones, quinacridones, xanthenes, oxazines, oxazolines, thioxanthenes, indigoids, thioindigoids, naphthalimides, cyanines, xanthenes, methines, lactones, coumarins, bis-benzoxazolylthiophenes (BBOTs), naphthalenetetracarboxylic acid derivatives, monoazo and diazo dyes, triarylmethanes, aminoketones, bis(styryl)biphenyl derivatives, and the like, as well as combinations comprising at least one of the above colorants. Colorants are generally used in an amount of 0.1 to 5 parts by weight based on 100 parts by weight of the total composition excluding any fillers.

[0100] Suitable blowing agents include, for example, those which produce low boiling halohydrocarbons and carbon dioxide; blowing agents which are solid at room temperature and which produce a gas, such as nitrogen, carbon dioxide, ammonia gas, etc., when heated above their decomposition temperature, such as azodicarbonamide, metal salts of azodicarbonamide, 4,4'oxybis(benzenesulfonylhydrazide), sodium bicarbonate, ammonium carbonate, etc., or combinations comprising at least one of the above blowing agents. The blowing agent is generally used in an amount of 1 to 20 parts by weight based on 100 parts by weight of the total composition excluding any fillers.

[0101] In addition, materials for improving flowability and other properties may be added to the composition, such as low molecular weight hydrocarbon resins. A particularly useful class of low molecular weight hydrocarbon resins is derived from petroleum C5-C9 feedstocks derived from unsaturated C5-C9 monomers obtained from petroleum cracking. Non-limiting examples include olefins, such as pentene, hexene, heptene, and the like; diolefins, such as pentadiene, hexadiene, and the like; cyclic olefins and diolefins, such as cyclopentane, cyclopentadiene, cyclohexene, cyclohexadiene, methylcyclopentadiene, and the like; cyclic diolefin dienes, such as dicyclopentadiene, methylcyclopentadiene dimer, and the like; and aromatic hydrocarbons, such as vinyltoluene, indene, methylindene, and the like. The resins may additionally be partially or fully hydrogenated.

[0102] Uses of blended polyhydroxyalkanoate / amorphous polyhydroxyalkanoate compositions

[0103] Provided herein is a method for forming a blended polyhydroxyalkanoate / amorphous polyhydroxyalkanoate composition, which includes mixing a PHA and an amorphous polyhydroxyalkanoate, optionally in the presence of a peroxide and a co-crosslinker, under conditions sufficient to form a blended mixture capable of forming an article of manufacture having desired physical and mechanical properties.

[0104] In one embodiment, a method is provided for improving the functional properties of a PHA through melting and cooling of an amorphous polyhydroxyalkanoate in the presence of a PHA, the method comprising the steps of: (a) providing a PHA and an amorphous polyhydroxyalkanoate; (b) blending the PHA and the amorphous polyhydroxyalkanoate to form a mixture; (c) heating the mixture to between 50°C and 250°C; and (d) rendering the PHA and the amorphous polyhydroxyalkanoate miscible, thereby affecting functional modifications of the amorphous polyhydroxyalkanoate and the PHA, the functional modifications increasing the impact strength, toughness, and elongation of the final product.

[0105] In another aspect, there is provided a method for improving the functional properties of PHA through melting and cooling of an amorphous polyhydroxyalkanoate in the presence of a PHA, the method comprising the steps of: (a) providing a PHA, an amorphous polyhydroxyalkanoate, a peroxide, and a co-crosslinking agent; (b) blending the PHA, the amorphous polyhydroxyalkanoate, the peroxide, and the co-crosslinking agent to form a mixture; and (c) heating the mixture to between 50° C. and 250° C. to make the PHA and the amorphous polyhydroxyalkanoate miscible, thereby affecting functional modifications of the amorphous polyhydroxyalkanoate and the PHA, the functional modifications increasing the impact strength, toughness, and elongation of the final product.

[0106] In yet another aspect, there is provided a method for improving the functional properties of PHA through melting and cooling of an amorphous polyhydroxyalkanoate in the presence of a PHA, the method comprising the steps of: (a) providing a PHA, an amorphous polyhydroxyalkanoate, a peroxide, and a co-crosslinking agent; (b) blending the PHA, amorphous polyhydroxyalkanoate, peroxide, and co-crosslinking agent to form a mixture; (c) subjecting the mixture to another blending operation in which additional peroxide and co-crosslinking agent are added to the mixture; and (e) heating the mixture to between 50° C. and 250° C. to make the PHA and amorphous polyhydroxyalkanoate miscible, thereby affecting functional modifications of the amorphous polyhydroxyalkanoate and the PHA, which functional modifications increase the impact strength, toughness, and elongation of the final product.

[0107] In yet another aspect, there is provided a method for improving the functional properties of PHA through melting and cooling of amorphous polyhydroxyalkanoate in the presence of PHA, the method comprising the steps of: (a) providing a PHA, an amorphous polyhydroxyalkanoate, a peroxide, and a co-crosslinking agent; (b) blending the PHA and amorphous polyhydroxyalkanoate to form a mixture; (c) subjecting the mixture to another blending operation in which a peroxide and a co-crosslinking agent are added to the mixture; and (e) heating the mixture to between 50° C. and 250° C. to make the PHA and amorphous polyhydroxyalkanoate miscible, thereby affecting functional modifications of the amorphous polyhydroxyalkanoate and the PHA, which functional modifications increase the impact strength, toughness, and elongation of the final product.

[0108] In some embodiments, blended compositions are made by melt mixing the individual components to produce a mixture. The mixture is then used to fabricate parts by injection molding, sheet and profile extrusion, fiber extrusion, cast film extrusion, blown film extrusion, thermoforming, vacuum forming, blow molding, and rotational molding operations. In film applications, the compositions of the present invention can be the complete film, or one or more layers in a multi-layer coextruded composite structure. Alternatively, the blended compositions can form different layers in a coextruded laminate, each layer having a slightly different composition.

[0109] In one embodiment, the PHA component and the amorphous polyhydroxyalkanoate component are in the form of powders of fine particle size, and the blended composition of the present invention is prepared by dry blending these components in predetermined proportions and subjecting the mixture to twin-screw extrusion.

[0110] Additionally, provided herein is a method for forming blended polymer resin pellets, the method comprising combining a PHA component and an amorphous polyhydroxyalkanoate component, and melting and molding the composition under suitable conditions to form blended resin pellets.

[0111] The novel blends described herein can be formed into commercially useful articles, such as films, sheets (including multi-layer sheets), molded articles, cutlery (or tableware), fibers, nonwovens, filaments, monofilaments, rods, tubes, bottles, pellets, or foams, formed by molding, extruding, thermoforming, or blow molding the polyhydroxyalkanoate / amorphous polyhydroxyalkanoate blend compositions.

[0112] In any of the compositions, methods, processes or articles described herein, the PHA component and the amorphous polyhydroxyalkanoate component may be in the form of fine particle size powder, pellets, or granules and may be combined by mixing or blending.

[0113] For the formation of useful articles, the compositions described herein are preferably treated (or processed) at a temperature above the crystalline melting point of the polymer and below the decomposition point of each component of the polymer composition (e.g., the additives mentioned above, except for some branching agents). In the thermoplastic condition, the polymer composition is processed into a desired shape and then cooled to fix the shape and promote crystallization. Such shapes can include, but are not limited to, fibers, filaments, nonwovens, monofilaments, films, sheets, rods, tubes, bottles, or other shapes. Such treatment (or processing) is carried out using any technique known in the art, such as, but not limited to, extrusion, injection molding, compression molding, foaming or blow molding (e.g., blown film, blown foam), calendaring, rotational molding, casting (e.g., cast sheet, cast film), or thermoforming.

[0114] The compositions are used to form a wide variety of useful products, including, but not limited to, automotive, consumer durable, construction, electrical, medical, and packaging products, any of which may have a secondary use as animal feed. For example, the polymer compositions can be used to form films (e.g., packaging films, agricultural films, mulch (or mulch) films, erosion control, hay bales wraps, slit films, food wraps, pallet wraps, automotive and appliance protective wraps), golf tees, caps and plugs, agricultural supports and stakes, paper and board coatings (e.g., for cups, plates, boxes, etc.), thermoformed articles (e.g., trays, containers, lids, yogurt pots, cup lids, plant pots, noodle bowls, molded articles, etc.), housings (e.g., for electronic devices, such as cell phones, PDA cases, music player cases, computer cases, etc.), bags (e.g., The products disclosed above are used to make, but are not limited to, garbage bags, shopping bags, food bags, compost bags, etc.), hygiene articles (e.g. diapers, sanitary products, incontinence products, disposable wipes, etc.), coatings for pellet products (e.g. pelletized fertilizers, herbicides, insecticides, seeds, etc.), injection molded articles (writing implements, cutlery such as forks, spoons, and knives, aquarium decorations, disk cases, etc.), solution and spun fibers and meltblown fabrics and nonwovens (yarns, yarns, wipes, stuffing, disposable absorbent articles), blow molded articles (deep containers, bottles, etc.), and foamed articles (cups, bowls, plates, packaging, etc.). All of the products disclosed above contain a main component (PHA), which, if ingested by an animal, can be metabolized by the animal and used as an energy source. Thus, an additional advantage of the product is that the product also functions as food for the living organism. The term animal includes all animals, including humans. Examples of animals are non-ruminant and ruminant animals. Ruminant animals include animals such as sheep, goats, cattle (e.g., beef cattle and dairy cattle). In certain embodiments, the animal is a non-ruminant animal.Non-ruminant animals include pet animals such as horses, cats and dogs; single stomach animals such as pigs or domestic pigs (including but not limited to piglets, growers and sows); poultry such as turkeys, ducks and chickens (including but not limited to broiler chicks, layer hens); fish (including but not limited to salmon, trout, tilapia, catfish, carp); seabirds (including but not limited to gulls, pelicans, terns), marine animals (including but not limited to whales, turtles, dolphins, sharks) and crustaceans (including but not limited to shrimp and prawns).

[0115] Thermoforming is a process that uses a thermoplastic film or sheet. A polymeric composition is processed into a film or sheet. The sheet of polymer is then placed in an oven to heat it. Once it is soft enough to be molded, it is transferred to a mold and formed into a shape.

[0116] During thermoforming, when the softening point of a semi-crystalline polymer is reached, the polymer sheet begins to sag. The window between softening and droop is usually narrow; therefore, it can be difficult to transfer the softened polymer sheet to a mold fast enough. Branching of the polymer can be used to increase the melt strength of the polymer so that the sheet is more easily processed and maintains structural integrity. Measuring the sag of a sample piece of the polymer as it is heated is a way to measure the relative size of the processing window for thermoforming.

[0117] Blow molding (which is similar to thermoforming and is used to make deep drawn products such as bottles and similar products with deep interiors) also benefits from the increased elasticity and melt strength and reduced sagging of the polymer compositions described herein.

[0118] The following specific examples are to be construed as merely illustrative, and not limiting of the remainder of the disclosure in any way whatsoever. Without further elaboration, one skilled in the art can, based on the description herein, utilize the present invention to its fullest extent. All documents cited herein are incorporated by reference in their entirety.

[0119] The present invention allows for the production of polymer blends that have high amounts of bio-based carbon and a favorable balance of desirable physical properties, particularly high impact properties (measured by notched Izod testing) and high flexural modulus without inducing brittleness.

[0120] Although several embodiments have been disclosed, it will be appreciated by those skilled in the art that various modifications, alternative constructions and equivalents may be used without departing from the scope of the disclosed embodiments. Additionally, a number of well-known processes and elements have not been described in order to avoid unnecessarily obscuring the present invention. Thus, the above description should not be understood as limiting the scope of the present invention.

[0121] When a range of values ​​is given, each intervening value between the upper and lower limits of the range is understood to be specifically disclosed, to the tenth of the unit of the lower limit, unless the context clearly dictates otherwise. Each smaller range between a stated value or intermediate value in a stated range and another stated value or intermediate value in a stated range is included. The upper and lower limits of these smaller ranges may be independently included or excluded in the range, and each range in which one or both of the limits are included in the smaller range or neither are included in the smaller range is also included within the invention, subject to the specifically excluded limit in the stated range. When a stated range includes one or both of the limits, ranges excluding one or both of the included limits are also included.

[0122] As used in this specification and the appended claims, the singular forms "a," "an," and "the" include plurals unless the context clearly dictates otherwise. Thus, for example, reference to "a process" includes a plurality of such processes, and reference to "the dielectric material" includes reference to one or more dielectric materials and equivalents thereof known to those skilled in the art, and so forth.

[0123] Additionally, as used in this specification and the claims that follow, the words "comprise," "comprising," "include," "including," and "includes" are intended to specify the presence of stated features, integers, components, or steps, but do not exclude the presence or addition of one or more other features, integers, components, steps, acts, or groups.

Claims

1. A biodegradable polymer composition comprising a polymer blend, the polymer blend comprising a PHA and an amorphous polymer, the PHB content in the PHA blend being in the range of 70-97.5% by weight of the total PHA content in the PHA blend, and the aPHA content in the PHA blend being in the range of 2.5-30% by weight of the total PHA content in the PHA blend.

2. 2. The biodegradable polymer composition of claim 1, wherein the amorphous polymer is an aPHA having a glass transition temperature (Tg) below 20°C and a melting temperature (TM) between 80 and 180°C.

3. 10. The biodegradable polymer composition of claim 1 further comprising nucleating agents, free radical initiators, branching agents, coupling agents / co-crosslinking agents, heat stabilizers, antioxidants, slip agents, colorants, and other functional additives.

4. The PHA includes poly(3-hydroxybutyrate) homopolymer (PHB), polyhydroxyvalerate (PHV), polyhydroxybutyrate-covalerate (PHBV), polyhydroxyhexanoate (PHHx), poly 3-hydroxyalkanoate (e.g., poly 3-hydroxypropionate (hereinafter referred to as P3HP), poly 3-hydroxybutyrate (hereinafter referred to as PHB) and poly 3-hydroxyvalerate), poly 4-hydroxyalkanoate (e.g., poly 4-hydroxybutyrate (hereinafter referred to as P4HB), poly 4-hydroxyvalerate (hereinafter referred to as P4HV)), and poly 5-hydroxyalkanoate (e.g., poly 5-hydroxyvalerate (hereinafter referred to as P5HV)), 2. The biodegradable polymer composition of claim 1, selected from poly 3-hydroxybutyrate-co-3-hydroxypropionate (hereinafter referred to as PHB3HP), poly 3-hydroxybutyrate-co-4-hydroxybutyrate (hereinafter referred to as PHB4HB), poly 3-hydroxybutyrate-co-4-hydroxyvalerate (hereinafter referred to as PHB4HV), poly 3-hydroxybutyrate-co-3-hydroxyvalerate (hereinafter referred to as PHB3HV), poly 3-hydroxybutyrate-co-3-hydroxyhexanoate (hereinafter referred to as PHB3HH), and poly 3-hydroxybutyrate-co-5-hydroxyvalerate (hereinafter referred to as PHB5HV), and combinations thereof, including polymer blends.

5. A biodegradable and biocompostable article made from the polymer composition of claim 1.

6. 13. A durable, injection moldable material made from the polymer composition of claim 1.

7. A thermoformed material made from the polymer composition of claim 1.

8. 4. The biodegradable polymer composition of claim 3, wherein the branching agent is selected from the group consisting of peroxides, azo derivatives, peresters, and peroxycarbonates.

9. 4. The biodegradable polymer composition of claim 3, wherein the free radical initiator is selected from the group consisting of organic peroxides.

10. 10. The biodegradable polymer composition of claim 9, wherein the organic peroxide is selected from the group consisting of dialkyl organic peroxides.

11. The dialkyl organic peroxide is 2,5-dimethyl-2,5-di(t-butylperoxy)hexane, 2,5-bis(t-butylperoxy)-2,5-dimethylhexane, 2,5-dimethyl-di(t-butylperoxy)hexyne-3, di-t-butyl peroxide, dicumyl peroxide, benzoyl peroxide, di-t-amyl peroxide, t-amylperoxy-2-ethylhexyl carbonate (TAEC), t-butylcumyl peroxide, n-butyl-4,4-bis(t-butylperoxy)valerate, 1,1-di(t-butylperoxy)-3,3,5-trimethylcyclohexane, 1,1-bis(t-butylperoxy)-3,3,5-trimethylcyclohexane (CPK), 1,1-di(t-butylperoxy) 11. The biodegradable polymer composition of claim 10, wherein the polymer is selected from the group consisting of ethyl-3,3-di(t-butylperoxy)cyclohexane, 1,1-di(t-amylperoxy)cyclohexane, 2,2-di(t-butylperoxy)butane, ethyl-3,3-di(t-butylperoxy)butyrate, 2,2-di(t-amylperoxy)propane, ethyl-3,3-di(t-amylperoxy)butyrate, t-butylperoxyacetate, t-amylperoxyacetate, t-butylperoxybenzoate, t-amylperoxybenzoate, di-t-butyldiperoxyphthalate, preferably di-(tert-butylperoxyisopropyl)benzene (dicumylperoxide) (VulCup®), and combinations and mixtures thereof.

12. 2. The biodegradable polymer composition of claim 1, wherein the coupling agent is selected from the group consisting of divinylbenzene, triallyl cyanurate, triallyl isocyanurate, hyperbranched or dendritic polyesters, such as dendritic and hyperbranched acrylates, such as urethane acrylates.

13. 4. The biodegradable polymer composition of claim 3, wherein the slip agent is selected from the group consisting of stearic acid, amide waxes, ester waxes, metal carboxylates, and carboxylic acids.

14. 10. The biodegradable polymer composition of claim 1 further comprising a functional additive.

15. 15. The biodegradable polymer composition of claim 14, wherein the functional additives include colorants (including carbon black), nucleating agents, stabilizers, coupling agents, processing aids, and reinforcing agents.

16. A thermoformed moldable article for food products comprising a polyhydroxyalkanoate (PHA), an amorphous PHA (aPHA), a peroxide, and a coupling agent.

17. A food product molded in the shape of cutlery, comprising a continuous layer and a discontinuous phase, said continuous layer being made of polyhydroxyalkanoate (PHA) and said discontinuous phase being aPHA.

18. 1. A food product molded in the shape of a drinking straw, comprising a continuous layer and a discontinuous phase, said continuous layer being made of polyhydroxyalkanoate (PHA) and said discontinuous phase being amorphous PHA.

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