WO2015057694A2 - Optically clear biodegradable oplyester blends - Google Patents

Abstract

Compositions of PLA with an aromatic/aliphatic polyester having low % Haze but fast crystallization rates are described as well as methods of making the same.

Description

OPTICALLY CLEAR BIODEGRADABLE POLYESTER BLENDS RELATED APPLICATION(S)

[0001] This application claims the benefit of U.S. Provisional Application No. 61/891,586, filed on October 16, 2013 and U.S. Provisional Application No.

61/912,042, filed on December 5, 2013. The entire teachings of the above applications are incorporated herein by reference.

BACKGROUND OF THE INVENTION

[0002] Biodegradable plastics are of increasing industrial interest as

replacements or supplements for non-biodegradable plastics in a wide range of applications and in particular for film packaging applications. Packaging plays an important role in the transit, warehouse storage and shelf or display counter storage of many products. The material properties that are most important for many film packaging applications include toughness, tear strength and optical clarity. For food packaging applications, refrigeration and freezer stability, heat resistance, and low gas diffusion impose additional requirements on the polymer film properties,

[0003] Achieving these properties generally involves blending two or more biodegradable polymers together along with various processing and mineral additives. The biodegradable polymer blend typically includes a polymer that is stiff and rigid which gives mechanical strength to the blend allowing it to be melt formed into a film and another polymer that is soft and flexible which provides toughness and impact strength to the finished film.

[0004] Polybutylene-adipate-terephthalate (PBAT) is low modulus, aliphatic/ aromatic, compostable polyester that has been incorporated into biodegradable polymer blends for making polymer films. Its low modulus and low glass transition temperature (T_g) make PBAT a very soft and tough material but also makes it extremely difficult to process into films. Addition of stiff compostable polymers such as poly lactic acid (PL A) to PBAT improves the overall processability of the PBAT while maintaining the biodegradable film properties. However, PBAT is also known to have a rather slow rate of crystallization relative to the rate required for commercial production of films. Nucleating agents which increase the PBAT nucleation rate are therefore needed as well with PBAT and include such

compounds as calcium carbonate and talc minerals. These same mineral fillers however impart a haze to the film making it opaque which is undesirable in some film packing applications.

[0005] There is therefore a need to develop biodegradable, tough, optically clear films that fulfill the demanding needs of film packaging applications.

SUMMARY OF THE INVENTION

[0006] Described herein are visually clear (excellent clarity with low % Haze), biodegradable film compositions comprising an aromatic/aliphatic polyester and a polylactic acid (PLA), methods of making such compositions, and pellets and articles formed from such blends. In particular embodiments, the aromatic/aliphatic polyester is polybutylene adipate-terephthalate. In particular, when the PBAT is blended with PLA and melt-processed, a low haze (< 20% as measured by a

Hazemeter), optically clear film is produced having an ash content < 0.7% by weight and a crystallization temperature (T_c) of at least 80°C. In one aspect of the embodiment, the PLA and polybutylene adipate-terephthalate is blended i.e., to a homogeneous blend. In certain aspects, the polymers of the compositions are mixed together to form a blend,

[0007] In any of the compositions or methods disclosed herein, the

biodegradable aromatic/aliphatic polyester can have a glass transition temperature (Tg) of about 0°C or less, of about -10°C or less, or of about -20°C or less. The glass transition temperature is the temperature at which an amorphous solid, such as glass or a polymer, becomes brittle on cooling, or soft on heating. As the temperature of a polymer drops below its Tg, it behaves in an increasingly brittle manner. As the temperature rises above the Tg, the polymer becomes more rubber-like. In particular embodiments, the aromatic/aliphatic polyester is a polybutylene adipate- terephthalate. In a further embodiment, the polylactic acid is derived from renewable resources and is composed of L-lactide monomer sequences providing a % crystallinity of at least 35%, Tg of about 60°C, of about 63 °C or about 65°C and a Tm of about 173°C₅ of about 175°C or about 178°C as measured by differential scanning calorimetry (DSC).

[0008] Additives may also be included in the compositions and methods of the invention such as waxes, anti-slip agents, anti-blocking agents, anti-stats, antioxidants, plasticizers, fungicides, heat stabilizers, UV stabilizers and lubricants. Excluded from these additives are the mineral fillers calcium carbonate, calcium sulfate, talc, wollastonite, kaolin and the like.

[0009] In still another embodiment, a method of preparing a film comprising a blend of PBAT and PLA polymer composition is described.

[0010] In still another embodiment, a method is described of making an article comprising a polybutylene adipate-terephthalate and polylactic acid composition comprising: melt-blending PLA and polybutylene adipate-terephthalate and optionally processing additives under conditions that cause melting of all the components, thereby forming a molten polymer blend composition; and forming an article from the molten polymer composition such as blown film; thereby making an article comprising a polybutylene adipate-terephthalate and PLA polymer composition.

[0011] In certain embodiments, a film is prepared by the methods described herein, the resultant film has excellent clarity and low haze according to ASTM Dl 003-92, low ash content according to ASTM D5630-13 and a high crystallization rate (T_c value as measured by DSC) than a corresponding PLA aromatic/aliphatic polyester blend. The film also has excellent tear and puncture toughness, good balance of strength and stiffness, excellent seal strength, good printablity properties, low odor levels and is free of bisphenol A or phthalate-type plasticizers. In some aspects, the film possesses optical and mechanical properties that are 25% greater, 50% greater or 75-100% greater. In certain aspects, the film is a blend of polybutylene adipate-terephthalate, polylactic lactic and processing additives.

DETAILED DESCRIPTION

[0012] The invention provides optically clear, biodegradable polymer compositions and methods of preparing biodegradable polymer films with improved crystallization and haze properties without the need for mineral-based nucleating agents. The polymer compositions comprise polybutylene adipate-terephthalate (PBAT), polylactic acid (PLA) and optionally processing additives. The use of certain commercially available PBAT materials promotes the desired properties of low haze and fast crystallization rate in films made from blends of the PBAT with PLA which would be required for blown film production of packaging films or other applications without the use of mineral fillers or mineral-type nucleating agents. In addition, the film composition described herein has excellent tear and puncture toughness, a good balance of strength and stiffness, excellent seal strength, good printability, low odor levels and can be formulated without the addition of bisphenol A or phfhalate-type plasticizers which are considered to be potential health hazards. In terms of processing, the composition is easy to process and can be done so on conventional blown film extrusion equipment due to its durability and high melt strength properties. It also allows significant downgauging (a method of reducing the amount of material in a product) during film production which reduces the overall cost to manufacture.

[0013] In one aspect, the weight ratio of PBAT to PLA in the blend is 95/5, 94/6, 93/7, 92/8, 91/9, 90/10 or 89/11. In a further aspect the PBAT or PBAT/PLA blend material has an ash content as measured by ASTM D5630-13 of < 1.0% by weight, < 0.9% by weight, < 0.8% by weight, <0.7% by weight, <0.6% by weight, <0.5% by weight or <0.4% by weight. In a further aspect of the invention, the crystallization temperature, T_c, of the polybutylene adipate-terephthalate is at least 89°C, 90°C, 91°C, 92°C, 93°C, 94°C, 95°C, 96°C, 97°C, 98°C, 99°C or 100°C. In a further aspect, the % Haze of a film made from a blend of the PBAT with polylactic acid and optional processing aids is less than 30%, 25%, 20%, 1 %, 10%, 5% or 1%. In a further aspect of the invention, the PBAT is ENPOL^® PBG7070 sourced from Samsung Fine Chemicals Co. Ltd.

AROMATIC/ALIPHATIC POLYESTER

[0014] The biodegradable aromatic/aliphatic polyester is a co polymer of: i) at least one aliphatic dicarboxylic acid; and/or ii) at least one aromatic dicarboxylic acid; and iii) a dihydroxy compound, in certain embodiments, the aliphatic dicarboxylic acid is a C₂ to C₁₂ aliphatic dicarboxylic acid such as, succinic acid, glutaric acid, dimethyl glutaric acid, adipic acid, sebacic acid or azelaic acid. In certain embodiments, the aromatic dicarboxylic acid is terephthalic acid or naphthalene dicarboxylic acid. In the embodiments of the invention, the

aromatic/aliphatic polyester is polybutylene adipate-terephthalate.

[00015] The polyesters can be made from fossil-based carbon sources i.e., a petroleum-based polymer, e.g., synthetic polyesters such as, but not limited to, synthetic polyesters, or portions of the polyester can be made from biomass or other renewable sources of carbon,

[0016] Aromatic polyesters, which are not biodegradable, are synthesized by the polycondensation of aliphatic diols and aromatic dicarboxylic acids. The aromatic ring is resistant to hydrolysis, preventing biodegradability. Polyethylene

terephthalate (PET) and polybutylene terephthalate (PBT) are formed by the polycondensation of aliphatic glycols and terephthalic acid. The biodegradability of aromatic polyesters can be modified by the addition of monomers that are not resistant to hydrolysis, aliphatic diol or diacid groups. The addition of such hydrolysis-sensitive monomers creates weak spots for hydrolysis to occur.

[0017] In the synthesis of polybutylene adipate-terephthalate (PBAT), butanediol is the diol, and the acids are adipic and terephthalic acids. Commercial examples include e.g., ECOFLEX^® (BASF), EASTAR BIO ^® (Novamont),

ENPOL^® (Samsung Fine Chemicals Co. Ltd.). PBAT has a melt temperature (T_m) of about 110°C to about 120°C, as measured by differential scanning calorimetry (DSC). In preferred embodiments, the PBAT chosen for blending with PLA and producing clear films is ENPOL^® PBG7070 from Samsung Fine Chemicals.

[0018] Biodegradable aromatic polymers therefore include polyesters containing aliphatic components. Among the polyesters are ester polycondensates containing aliphatic constituents or poly(hydroxycarboxylic) acids. In certain embodiments, the ester polycondensates include diacids/diol aliphatic polyesters such as polybutylene succinate, polybutylene succinate co-adipate, aliphatic/aromatic polyesters such as terpolymers made of butyl enes diol, adipic acid and terephthalic acid.

[0019] Examples of biodegradable aromatic/aliphatic polyesters therefore include, but are not limited to, various copolyesters of PBT with aliphatic diacids or diols incorporated into the polymer backbone to render the copolyesters biodegradable or compostable; and various aliphatic polyesters and copolyesters derived from dibasic acids, e.g., succinic acid, glutaric acid, adipic acid, sebacic acid, azealic acid, or their derivatives {e.g., alkyl esters, acid chlorides, or their anhydrides) and dihydroxy compounds (diols) such as C₂-C₆ alkanediols and C5-C10 cycloalkanediols, such as ethylene glycol, propylene glycol, 1 ,4-butanediol, 1,6 hexanediol. In other embodiments, the diol is 1,4 cyclohexanedimethanol. In preferred embodiments, the dihydroxy compound is ethylene glycol, or 1,4- butanediol. Biodegradable diols are preferred in certain embodiments,

[0020] The biodegradable aromatic/aliphatic polyester can be a co-polyester. It can also itself be a blend of such polyesters or co-polyesters. For example, the co- polyester is a co-polyester of polybutylene adipate-terephthalate and another polyester.

POLYLACTIC ACID (PLA)

[0021] Polylactic acid (PLA) is a biobased, biodegradable, thermoplastic aliphatic polyester that is currently being produced on a large scale for commercial applications ranging from nonwoven fibers to packaging films. Production of PLA is usually carried out by bacterial fermentation of corn sugar (dextrose) whereby the sugar is first converted into lactic acid. The lactic acid through a series of synthetic reactions thru a lactide intermediate is then polymerized via a ring-opening polymerization (ROP), using tin-based catalysts, to polylactic acid. Depending on the type of catalyst employed in the synthesis, either L or D-polylactic acids (PLLA or PLDA) can be obtained. PLLA is 37% crystalline with a Tg~ 50-60°C and a Tm — 173-178°C. The mechanical properties of PLLA are reported as being similar to PETE. The abbreviation PLA usually refers to the PLLA structural form. When PLLA and PLDA are mixed together, they can form eutectoid stereo complexes with enhanced properties (50°C higher Tm) than either PLLA or PDLA. These are being investigated as biodegradable materials for high temperature applications.

[0022] The biodegradability of PLA has been found mainly to occur through the hydrolysis of the polyester functional groups present in PLA. The degradation is essentially a two-step process whereby the PLA is first decomposed under high humidity and temperature (industrial/municipal-type composting) to produce lower molecular weight chains or lactic monomer. The second step is consumption of the low molecular weight PLA and lactic acid by microbes present in nature.

[0023] Several companies currently are manufacturing PLA from sugar feed sources. These include Nature Works INGEO^® (US), Galactic (Belgium) and Corbion PURAC (Netherlands). Nature Works, a joint venture between Cargill and Teijin operating since 2003, is currently the largest commercial producer of PLA resin.

[0024] The one drawback to processing of PLA into various products is that it is an extremely stiff and brittle material. Therefore it must be blended with other polymers in order to widen its processing window during forming, One potential problem with this approach is that additives and polymers blended with the PLA also have an effect on its biodegradability. Polymers which have had the most success aiding in processing of PLA without adversely affecting its biodegradability include polybutylene adipate-succinate (PBAT), polybutylene-succinate (PBS) or polybutylene-succinate-adipate (PBSA). All of these polymers are biodegradable or compostable and help to improve the toughness and impact resistance of the PLA.

BLENDS OF AROMATIC/ALIPHATIC POLYESTERS WITH PLA

[0025] In certain embodiments, the polymers for use in the methods and compositions are blended in the presence of processing additives to form films with improved optical clarity and crystallization properties. The percentages of PLA to aromatic/aliphatic polyesters are 5% to 1 1% by weight. In certain compositions of the invention, the percentage of PLA to aromatic/aliphatic polyester of the total polymer compositions ranges from about 5% PLA to about 95% aromatic/aliphatic polyester or about 89% aromatic/aliphatic polyester to about 11% PLA. For example the PLA/aromatic/aliphatic polyester ratio can be 5/95, 6/94, 7/93, 8/92, 9/91, 10/90 or 11/89.

[0026] PLA and biodegradable aromatic/aliphatic polyesters such as PBAT can be combined to make blends of the polymers. In one embodiment, the blend is homogeneous.

[0027] The amount of PBAT in the overall blend is 89 to 95% by weight of the total polymer blend. The selection and amount of each polymer will affect the softness, stiffness, texture, toughness, crystallization rate, optical properties and other properties of the final product as will be understood by those of ordinary skill in the art. Typically, the PLA component is present in the blend in an amount of from 5% to 11% by weight, preferably from about 8% to about 0%, by total weight of the total polymer components of the composition.

[0028] In certain embodiments, the amount of PLA in the overall blend can be about 1% by weight, about 5%, about 6%, about 7%, about 8%, about 9%, about 10% or about 11% by weight. The selection and amount of each polymer will affect the softness, stiffness, texture, toughness, and other properties of the final product as will be understood by those of ordinary skill in the art. Typically, the PLA component is present in the blend in an amount of from about 5% to 11%, preferably from about 6% to about 10%, more preferably from about 8% to about 10%, by total weight of the total polymer components.

[0029] Each polymer component can contain a single polymer species or a blend of two or more species. For instance, the PLA component can in turn be a blend of L-PLA and D-PLA species as described above. Likewise, the biodegradable aromatic/aliphatic polyester component can be a mixture or blend of more than one biodegradable aromatic/aliphatic polyester.

[0030] Methods for making and using thermoplastic compositions are well known to those of skill in the art. The majority of polymers films are manufactured by a film blowing process also known as blown film extrusion. In this process a single or twin screw extruder is used to first to mix and melt a polymer blend or homopolymer. Once the homopolymer or polymer blend is molten, it is then pumped and extruded through a tubular die. The molten tube emerging vertically from the die is subject to both a moderate internal air pressure via an air inlet running through the die and a longitudinal force via take-off rollers located downstream. The air blown into the center of the extruded tube causes it to expand in the radial direction while the take-off rollers cause expansion in the longitudinal direction forming a bubble. As the bubble moves out of the die area, it is simultaneously cooled by an external air ring. Further extension of the bubble stops at the freeze line (frost line) due to crystallization of the melt from the air cooling. The molten polymer gradually deforms into a stable solid cylindrical bubble beyond the freeze line. The take-off or nip rollers located above the bubble collect the film as well as seal the top of the bubble in order to maintain the air pressure inside the bubble. The bubble is gradually flattened in line using a collapsing device such as a tent frame and then slit or collected for slitting to a flat film. The startup of the film blowing operation normally involves the pulling of the uninflated extruded tube, with the help of a cable, until it becomes pinched between the nip rollers. Internal air pressure if subsequently applied to form the bubble. The blow-up ratio (BUR), defined as the ratio of the bubble diameter to the die diameter is normally in range of 1.5 - 4. The larger the ratio, the higher the polymer melt strength that is needed. The air pressure in the bubble, which is responsible for the blowing, is typically in the range of 1.5 - 3 psi.

[0031] In polymer packaging films, haze is often as important a material property as color in the quality control of manufactured products. The term haze refers to the visual clarity of a material and is calculated by measuring the percentage of normal incident visible light that is transmitted from a light source through a film sample. Stated another way, haze is the cloudy appearance of an otherwise transparent film sample caused by light scattering from within the film or from the surface of the film. It is generally accepted that if the amount of transmitted light through a film sample deviates more than 2.5° from an incident light beam, the light flux is considered to be haze. Haze is normally caused by surface imperfections, density changes or inclusions that scatter light such as could be caused by addition of mineral fillers or other additives. ASTM D1003-92 outlines the method used for measuring haze in films samples. In the ASTM method, a ITV7VIS spectropho meter or a Hazemeter equipped with an integrating sphere can be used to measure the % of haze. The procedure calls for a 2 inch diameter disc cut from a polymer film to be placed over the aperture of the integrating sphere. Four consecutive visible light transmission readings are taken with different configurations of the integrating sphere and sample while measuring the light output using a photocell detector. The four integrating sphere

configurations measure the total incident light intensity (Tl), the total light transmitted by the film sample (T2), the light scattered by the instrument (T3) and finally the light scattered by the instrument and sample (T4). The % Haze is calculated using the T1-T4 measurements by applying the following equation:

% Haze = [(T4/T2)-(T3/T1)] x 100%

The lower the % Haze value, the higher the clarity of the film sample. Films with a % Haze greater than 30% are considered to be diffusing materials, Typical % Haze values for some polymers are as follows: low density polyethylene - % Haze = 1.3- 27.5; polyethylene-co- vinyl alcohol - % Haze— 0.5-1.9; polypropylene - % Haze = 1 1 ; polylactic acid - % Haze = 2-2.2; polycarbonate - % Haze =1-1.1. Note that these values are dependent on film surface roughness and the presence of film defects.

[0032] Another factor which influences the clarity of polymer films is its degree of crystallinity. Most polymers are "semi-crystalline" materials where portions or zones of the polymer chains are regularly ordered forming conformations or units cells reminiscent of those found in regular crystals of low molecular weight compounds. The other portions of the polymer chains are in a random or amorphous state. Such an arrangement, however, is only possible and stable if sufficiently strong intermolecular forces exit between the polymers chains which overcome the tendency of chains to adopt a random chain configuration. Structural regularity of the polymer repeat units and low temperatures generally favor the crystallization of polymers. The amount or degree of crystallinity affects optical, mechanical, thermal, and chemical properties of a polymer and it typically ranges between 10- 80%). It is measured by several analytical methods including differential scanning calorimetry (DSC), X-ray diffraction (XRD) and bulk density. The crystallization of a polymer is a time-dependent process and several factors affect not only the speed at which it takes place (kinetics), but also the resulting crystalline morphology. In general a larger more coarse crystal size is normally associated with slow cooling of polymer from the melt phase while a smaller crystal size is achieved by fast cooling. Smaller polymer crystallites create a more flexible and transparent polymer as compared to a more coarse polymer crystal size. In order to prepare optically clear polymer films, it is therefore advantageous to use a process where the melted polymer or polymer blend is rapidly cooled as film is forming such as used in blow molding processes. One way to compare the rates of crystallization among polymers is to measure the temperature at which crystallization (Tc) begins to occur during cooling of the polymer from the melt. This can be easily measured using differential scanning calorimetry (DSC). In this technique, the heat flow rate to the polymer (differential power) is measured while the temperature of the sample, usually under an inert N2 atmosphere, is programmed (typically 5-20°C/min) to heat or cool above or below the melting temperature of the polymer. Because all materials have a finite heat capacity, heating or cooling of a polymer results in a flow of heat into or out of the sample. The heat flow when plotted versus temperature provides a scan from which the polymers thermal transitions such as its glass or melt transitions can be measured. To measure Tc, the crystallization temperature, a polymer is heat slightly above it melt temperature then slowly cooled. As the polymer crystallizes, heat will flow out of the sample and an exothermic peak will be detected. The temperature at which the maximum in the exothermic peak occurs is the crystallization

temperature. Generally a higher value of Tc indicates a faster polymer

crystallization rate.

ADDITIVES

[0033] Skilled practitioners will appreciate that the biodegradable blends of the present invention can be used in a wide range of film packaging applications and further, as is known to skilled practitioners, can contain one or more additive, e.g., a plasticizer, antioxidant, ultraviolet stabilizer, lubricant, slip/antiblock, mold release, and/or antistatic agent but not contain mineral based nucleating agents or fillers.

[0034] In certain embodiments, various additives are added to the compositions. Examples of these additives include antioxidants, thermal and UV absorbers or stabilizers (such as TINUVIN^® 234 and 326 ) and organic fillers, plasticizers, non- mineral nucleating agents, and radical scavengers, anti-slip agents, anti-blocking agents, waxes, and radical scavengers. Additionally, poly functional branching agents such as di vinyl benzene, trially cyanurate and the like may be added. The branching agent and/or cross-linking agent is added to one or more of these for easier incorporation into the polymer. For instance, the branching agent and or cross-linking agent is mixed with a plasticizer, e.g., a non-reactive plasticizer, e.g., a citric acid ester, and then compounded with the polymer under conditions to induce branching,

[0035] The additives are included in the thermoplastic compositions at a concentration of about 0.05 to about 20% by weight of the total composition. For example, the range in certain embodiments is about 0.05 to about 5% of the total composition.

[0036] The additive(s) can also be prepared as a masterbatch for example, by incorporating the additive(s) in a PLA or PBAT blend and producing pellets of the resultant composition for addition to subsequent processing. In a masterbatch the concentration of the additive(s) is (are) higher than the final amount for the product to allow for proportionate mixing of the additive in the final composition.

[0037] The additive is any compound known to those of skill in the art to be useful in the production of thermoplastics. Exemplary additives include, e.g., plasticizers (e.g., to increase flexibility of a thermoplastic composition), antioxidants (e.g., to protect the thermoplastic composition from degradation by ozone or oxygen), ultraviolet stabilizers (e.g., to protect against weathering), lubricants (e.g., to reduce friction), mold release, and antistatic agents. It is well within the skilled practitioner's abilities to determine whether an additive should be included in a thermoplastic composition and, if so, what additive and the amount that should be added to the composition to maintain low haze and desired optical properties.

[0038] Plasticizers are often used to change the glass transition temperature and modulus of the composition, but surfactants may also be used. Lubricants may also be used, e.g., in injection molding applications. Plasticizers, surfactants and lubricants may all therefore be included in the overall composition.

[0039] In other embodiments, the blend includes one or more plasticizers.

Examples of plasticizers include phthalic compounds (including, but not limited to, dimethyl phthalate, diethyl phthalate, dibutyi 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 octyl phthalate, octyl benzyl phthalate, n-hexyl n-decyl phthalate, n-octyl phthalate, and n-decyl phthalate), phosphoric compounds (including, but not limited to, tricresyl phosphate, trioctyl phosphate, triphenyl phosphate, octyl diphenyl phosphate, cresyl diphenyl phosphate, and trichloroethyl phosphate), adipic 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 compounds (including, but not limited to, dibutyl sebacate, dioctyl sebacate, diisooctyl sebacate, and butyl benzyl sebacate), azelaic compounds, citric compounds (including, but not limited to, triethyl citrate, acetyl triethyl citrate, tributyl citrate, acetyl tributyl citrate, and acetyl trioctyl citrate), glycolic compounds (including, but not limited to, methyl phthalyl ethyl glycolate, ethyl phthalyl ethyl glycolate, and butyl phthalyl ethyl glycolate), trimellitic compounds (including, but not limited to, trioctyl trimellitate and tri-n- octyl n-decyl trimellitate), phthalic isomer compounds (including, but not limited to, dioctyl isophthalate and dioctyl terephthalate), ricinoleic compounds (including, but not limited to, methyl acetyl, recinoleate and butyl acetyl recinoleate), polyester compounds (including, but not limited to reaction products of diols selected from butane diol, ethylene glycol, propane 1,2 diol, propane 1,3 diol, polyethylene glycol, glycerol, diacids selected from adipic acid, succinic acid, succinic anhydride and hydroxyacids such as hydroxystearic acid, epoxidized soy bean oil, chlorinated paraffins, chlorinated fatty acid esters, fatty acid compounds, plant oils, pigments, and acrylic compounds. The plasticizers may be used either alone respectively or in combinations with each other.

[0040] In certain embodiments, the compositions and methods of the invention include one or more surfactants. Surfactants are generally used to de-dust, lubricate, reduce surface tension, and/or densify. Examples of surfactants include, but are not limited to mineral oil, castor oil, and soybean oil. One mineral oil surfactant is DRA EOL® 34, available from Penreco (Dickinson, Texas, USA).

MAXSPERSE® W-6000 and W-3000 solid surfactants are available from Chemax Polymer Additives (Piedmont, South Carolina, USA). Non-ionic surfactants with HLB values ranging from about 2 to about 16 can be used, examples being TWEEN- 20, TWEEN-65, SPAN® 40 and SPAN® 85. [0041] Anionic surfactants include: aliphatic carboxylic acids such as lauric acid, myristic acid, palmitic acid, stearic acid, and oleic acid; fatty acid soaps such as sodium salts or potassium salts of the above aliphatic carboxylic acids; N-acyl-N- methylglycine salts, N-acyl-N-methyl-beta-alanine salts, N-acylglutamic acid salts, polyoxyethylene alkyl ether carboxylic acid salts, acylated peptides,

alkylbenzenesulfonic acid salts, alkylnaphthalenesulfonic acid salts,

naphthalenesulfonic acid salt-formalin polycondensation products,

melaminesulfonic acid salt-formalin polycondensation products,

dialkylsulfosuccinic acid ester salts, alkyl sulfosuccinate disalts, polyoxyethylene alkylsulfosuccinic acid disalts, alkylsulfoacetic acid salts, (alpha-olefinsulfonic acid salts, N-acylmethyltaurine salts, sodium dimethyl 5-sulfoisophthalate, sulfated oil, higher alcohol sulfuric acid ester salts, polyoxyethylene alkyl ether sulfuric acid salts, secondary higher alcohol ethoxysulfates, polyoxyethylene alkyl phenyl ether sulfuric acid salts, monoglysulfate, sulfuric acid ester salts of fatty acid

alkylolamides, polyoxyethylene alkyl ether phosphoric acid salts, polyoxyethylene alkyl phenyl ether phosphoric acid salts, alkyl phosphoric acid salts, sodium alkylamine oxide bistridecylsulfosuccinates, sodium dioctylsulfosuccinate, sodium dihexylsulfosuccinate, sodium dicyclohexylsulfosuccinate, sodium

diamylsulfosuccinate, sodium diisobutylsulfosuccinate, alkylamine guanidine polyoxyethanol, disodium sulfosuccinate ethoxylated alcohol half esters, disodium sulfosuccinate ethoxylated nonylphenol half esters, disodium isodecylsuifosuccmate, disodium N-octadecylsuIfosuccinamide, tetrasodium N-(l ,2-dicarboxyethyl)-N- octadecylsulfosuccinamide, disodium mono- or didodecyldiphenyl oxide

disulfonates, sodium diisopropylnaphthalenesulfonate, and neutralized condensed products from sodium naphthalenesulfonate.

[0042] One or more lubricants can also be added to the compositions and methods of the invention. Lubricants are normally used to reduce sticking to hot metal surfaces during processing and can include polyethylene, paraffin oils, and paraffin waxes in combination with metal stearates. Other lubricants include stearic acid, amide waxes, ester waxes, metal carboxylates, and carboxylic acids.

Lubricants are normally added to polymers in the range of about 0.1 percent to about 1 percent by weight, generally from about 0.7 percent to about 0.8 percent by weight of the compound. Solid lubricants is warmed and melted before or during processing of the blend.

[0043] One or more anti-microbial agents can also be added to the compositions and methods of the invention. An anti-microbial is a substance that kills or inhibits the growth of microorganisms such as bacteria, fungi, or protozoans, as well as destroying viruses. Antimicrobial drugs either kill microbes (microbicidal) or prevent the growth of microbes (micro bi static). A wide range of chemical and natural compounds are used as antimicrobials, including but not limited to: organic acids, essential oils, cations and elements (e.g., colloidal silver). Commercial examples include but are not limited to POLYSEPT® Z, UDA and AGION®.

[0044] POLYSEPT® Z (available from PolyChem Alloy) is an organic salt based, non-migratory antimicrobial. "UDA" is Urtica dioica agglutinin. AGION® is a silver compound. AMICAL™ 48 is diiodomethyl p-tolyl sulfone. In certain aspects the antimicrobial agent slows down degradation of the composition.

[0045] In film applications of the compositions and methods described herein, anti-block masterbatch is also added. A suitable example is a siip anti-block masterbatch mixture of erucamide (20% by weight) pelleted into PLA (62% by weight).

CROSS-LINKING AGENTS

[0046] Cross-linking agent, also referred to as co-agents, used in the methods and compositions of the invention are cross-linking agents comprising two or more reactive functional groups such as epoxides or double bonds. These cross-linking agents modify the properties of the polymer. These properties include, but are not limited to, melt strength or toughness. One type of cross-linking agent is an "epoxy functional compound." As used herein, "epoxy functional compound" is meant to include compounds with two or more epoxide groups capable of increasing the melt strength of polyhydroxyalkanoate polymers by branching, e.g., end branching as described above.

[0047] When an epoxy functional compound is used as the cross-linking agent in the disclosed methods, a branching agent is optional. As such one embodiment of the invention is a method of branching a starting polyhydroxyalkanoate polymer (PHA), comprising reacting a starting PHA with an epoxy functional compound. Alternatively, the invention is a method of branching a starting

polyhydroxyalkanoate polymer, comprising reacting a starting PHA, a branching agent and an epoxy functional compound. Alternatively, the invention is a method of branching a starting polyhydroxyalkanoate polymer, comprising reacting a starting PHA, and an epoxy functional compound in the absence of a branching agent. Such epoxy functional compounds can include epoxy-functional, styrene- acrylic polymers (such as, but not limited to, e.g., JONC YL© ADR-4368 (BASF), or MP-40 (Kaneka)), acrylic and/or polyolefm copolymers and oligomers containing glycidyl groups incorporated as side chains (such as, but not limited to, e.g., LOTADER® (Arkema), poly(ethylene-glycidyl methacrylate-co-methacrylate)), and epoxidized oils (such as, but not limited to, e.g., epoxidized soybean, olive, linseed, palm, peanut, coconut, seaweed, cod liver oils, or mixtures thereof, e.g.,

MERGINAT® ESBO (Hobum, Hamburg, Germany)and EDENOL® B 316 (Cognis, Dusseldorf, Germany)).

[0048] For example, reactive acrylics or functional acrylics cross-linking agents are used to increase the molecular weight of the polymer in the branched polymer compositions described herein. Such cross-linking agents are sold commercially. BASF, for instance, sells multiple compounds under the trade name "Joncryl", which are described in U.S. Pat. No. 6,984,694 to Blasius et al, "Oligomeric chain extenders for processing, post-processing and recycling of condensation polymers, synthesis, compositions and applications", incorporated herein by reference in its entirety, One such compound is JONCRYL® ADR-4368CS, which is styrene glycidyl methacrylate and is discussed below. Another is MP-40 (Kaneka), And still another is Petra line from Honeywell, see for example, U.S. Patent No.

5,723,730. Such polymers are often used in plastic recycling (e.g., in recycling of polyethylene terephthalate) to increase the molecular weight (or to mimic the increase of molecular weight) of the polymer being recycled. Such polymers often have the general structure:

R₃ is alkyl

x and y are 1-20

z is 2-20

[0049] E.I, du Pont de Nemours & Company sells multiple reactive compounds under the trade name ELVALOY®, which are ethylene copolymers, such as acrylate copolymers, elastomeric terpolymers, and other copolymers. One such compound is ELVALOY® PTW, which is a copolymer of ethylene-n-butyl acrylate and glycidyl methacrylate. Otnnova sells similar compounds under the trade names "SX64053," "SX64055," and "SX64056." Other entities also supply such compounds commercially.

[0050] Specific polyfunctional polymeric compounds with reactive epoxy functional groups are the styrene-acrylic copolymers. These materials are based on oligomers with styrene and acrylate building blocks that have glycidyl groups incorporated as side chains, A high number of epoxy groups per oligomer chain are used, for example 5, greater than 10, or greater than 20. These polymeric materials generally have a molecular weight greater than 3000, specifically greater than 4000, and more specifically greater than 6000. These are commercially available from S.C. Johnson Polymer, LLC (now owned by BASF) under the trade name

JONCRYL® ADR 4368 material. Other types of polyfunctional polymer materials with multiple epoxy groups are acrylic and/or polyolefin copolymers and oligomers containing glycidyl groups incorporated as side chains. A further example of such a polyfunctional carboxy-reactive material is a co- or ter-polymer including units of ethylene and glycidyl methacrylate (GMA), available under the trade name LOTADER® resin, sold by Arkeraa. These materials can further comprise methacrylate units that are not glycidyl. An example of this type is poly(ethylene- glycidyl methacrylate-co-methacrylate).

[0051] Fatty acid esters or naturally occurring oils containing epoxy groups (epoxidized) can also be 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 a mixture of these compounds. Particular preference is given to epoxidized soybean oil (e.g., MERGINAT® ESBO from Hobum, Hamburg, or EDENOL® B 316 from Cognis, Dusseldorf), but others may also be used.

[0052] Another type of cross-linking agent are agents with two or more double bonds. Cross-linking agents with two or more double bond cross-link PHAs by after reacting at the double bonds. Examples of these include: diallyl phthalate, pentaerythritol tetraacrylate, trimethylolpropane triacrylate, pentaerythritol triacrylate, dipentaerythritol pentaacrylate, diethylene glycol dimethacrylate, bis(2- methacryloxy ethy l)pho sphate .

[0053] In general, it appears that compounds with terminal epoxides may perform better than those with epoxide groups located elsewhere on the molecule.

[0054] Compounds having a relatively high number of end groups are the most desirable. Molecular weight may also play a role in this regard, and compounds with higher numbers of end groups relative to their molecular weight (e.g., the Joncryls are in the 3000 - 4000 g mol range) are likely to perform better than compounds with fewer end groups relative to their molecular weight (e.g., the Omnova products have molecular weights in the 100,000 - 800,000 g/mol range).

NUCLEATING AGENTS

[0055] An optional, non-mineral type, nucleating agent can be added to the composition to aid in its crystallization. Nucleating agents for various polymers include low-molecular organic compounds having a metal carboxylate group, for example, metal salts of such as octylic 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 monomethyl ester; high- molecular organic compounds having a metal carboxylate group, for example, metal salts of such as: carboxyl-group-containing polyethylene obtained by oxidation of polyethylene; carboxyl-group-containing polypropylene obtained by oxidation of polypropylene; copolymers of olefins, such as ethylene, propylene and butene- 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 organic compounds, for example: alpha-olefins branched at their 3-position carbon atom and having no fewer than 5 carbon atoms, such as 3,3 dimethylbutene-l,3-methylbutene-l,3- methylpentene-l,3-methylhexene-l, and 3,5,5-trimethylhexene-l ; polymers of vinylcycloalkanes such as vinylcyclopentane, vinyl cyclohexane, and

vinylnorbornane; 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 methylene bis-(2,4-tert-butyIphenyl)phosphate; sorbitol derivatives such as bis(p- methylbenzylidene) sorbitol and bis(p-ethylbenzylidene) sorbitol; and thioglycolic anhydride, p-toluenesulfonic acid. The above nucleating agents may be used either alone or in combinations with each other. In particular embodiments, the nucleating agent is cyanuric acid. In certain embodiments, the nucleating agent can also be another polymer (e.g., polymeric nucleating agents such as polyhydroxybutyrate (PHB)).

APPLICATION OF THE COMPOSITIONS

[0056] For the fabrication of useful articles, the compositions described herein are processed preferably at a temperature above the crystalline melting point of the polymers but below the decomposition point of any of the ingredients (e.g., the additives described above, with the exception of some branching agents) of the polymeric composition. While in heat plasticized condition, the polymeric composition is processed into a desired shape, and subsequently cooled to set the shape and induce crystallization. Such shapes can include, but are not limited to, a fiber, filament, film, sheet, rod, tube, bottle, or other shape. Such processing is performed using any art-known technique, such as, but not limited to, extrusion, injection molding, compression molding, blowing or blow molding (e.g., blown film, blowing of foam), calendaring, rotational molding, casting (e.g., cast sheet, cast film), or thermoforming.

[0057] The compositions are used to create, without limitation, a wide variety of useful products, e.g., medical, and packaging products. For instance, the polymeric compositions is used to make, without limitation, films (e.g., packaging films, agricultural film, mulch film, erosion control, hay bale wrap, slit film, food wrap, pallet wrap, protective automobile and appliance wrap, etc.), paper and board coatings (e.g., for cups, plates, boxes, etc.), bags (e.g., trash bags, grocery bags, food bags, compost bags, etc.), solution and spun fibers and melt blown fabrics and non- wovens (threads, yarns, wipes, wadding, disposable absorbent articles), blow moldings (deep containers, bottles, etc) and foamed articles (cups, bowls, plates, packaging, etc.).

[0058] The compositions described herein can be processed into films of varying thickness, for example, films of uniform thickness ranging from 10-200 microns, for example, 20-75 microns, 75 to 150 microns, or from 50-100 microns. Film layers can additionally be stacked to form multilayer films of the same or varying thicknesses or compositions. For example, a film can comprise two, three, four or more layers, where the layers can include one or more layers of a composition or compositions of the invention combined with other polymer layers, such as PHA layers, or PLA layers or PBAT layers and the like.

[0059] Articles made from the compositions can be annealed according to any of the methods disclosed in WO 2010/008445, filed June 19, 2009 and titled "Branched PHA Compositions, Methods For Their Production, And Use In Applications", which was filed in English and designated the United States. This application is incorporated by reference herein in its entirety.

[0060] The compositions described herein are provided in any suitable form convenient for an intended application. For example, the composition is provided in pellet for subsequent production of films, coatings, moldings or other articles.

[0061] The specific examples below are to be construed as merely illustrative, and not limitative of the remainder of the disclosure in any way whatsoever. Without further elaboration, it is believed that one skilled in the art can, based on the description herein, utilize the present invention to its fullest extent. All publications cited herein are hereby incorporated by reference in their entirety.

EXAMPLES

Materials

[0062] Table 1 summarizes the polybutylene adipate-terephthalate, polylactic acid and additives used to prepared the PBAT/PLA blend samples:

Experimental Methods

Measurement of Crystallization Temperature

[0063] A Perkin Elmer DSC was used to characterize the non-isothermal melt- crystallization kinetics of PBAT and PBAT/PLA blends. In this test, the sample (cut from a disc compression molded at 165 °C for one minute) was placed and crimped in the DSC sample pan. The sample was then exposed to 200 °C for one minute to melt all of the polymer blend crystals; it was then cooled to 160 °C at 40 °C/min and maintained at 160 °C for about 1 minute. The specimen was cooled to -50 °C at a rate of about 10 °C/min, As the polymer underwent crystallization on cooling, an exothermic peak in the "heat flow versus temperature" trace became evident. The peak-temperature of this exotherm was noted as the crystallization temperature or Tc. A higher Tc generally indicates faster crystallization kinetics.

Measurement of % Haze and Ash Content

[0064] Polymer film samples were measured for % Haze following the ASTM Dl 003-92 procedure using an X-Rite Color- Eye 7000A spectrophometer. The Ash Content of polymer film samples was measured following the procedure outlined in ASTM 5630. Example 1. Low Haze PBAT/PLA Films

[0065] In this example two different polybutylene adipate-terephthalate polymers are blended with PLA and made into films. The % Haze, Tc and Ash Content are measured and compared for each film blend.

[0066] All of the formulations are blended and compounded using a Leistritz, 27mm, co-rotating, twin-screw extruder using the following temperature profile (from feed to die) 165⁰C/164⁰C/165⁰C/165⁰C/167⁰C/l03⁰C/171⁰C/l08°C, screw speed is 125rpm and die pressure 2098psi. Prior to melt blending, the PLA is dried to a moisture content of approximately 250ppm using either an in-line dryer or airflow static dryer capable of holding a temperature of 80°C for 4 hours with an air flow rate > 0.5 ft3/min.

[0067] Table 1 shows a summary of the % Haze, Tc and Ash Content for PBAT and PBAT/PLA blends prepared using either ENPOL® PBG7070 from Samsung Fine Chemicals or ECOFLEX® F C2100 from BASF. Included in the comparison was a commercial PBAT/PLA blend having 8% by weight PLA obtained from

BASF called ECOVIA© F C2331.

[0068] Table 1. Summary of % Haze, crystallization temperature (Tc) and Ash Content for PBAT and PBAT/PLA formulations prepared from ENPOL® or

ECOFLEX® PBAT. PLA used in the blends was INGEO® 4032D from

NatureWorks. The talc used as nucleating agent in the formulations was

FLEXTALC® 610D from Specialty Chemicals.

%Ash

Material % Haze Content T_c (°C)

ENPOL* PBG7070 - 0.56 89.9

ENPOL^® PBG7070 + 8% PLA 16 0.56 80.4

ECOFLEX* F C 1200 - 0.41 37.1

ECOFLEX^® F CI 200 + 8% PLA + 1% Talc 48 1.5 88.6

ECOFLEX^® F C 1200 + 8% PLA + 2% Talc 50 2.5 89.0

ECOFLEX^® F C1200 + 8% PLA + 3% Talc 52 3.5 90.4 [0069] The data in Table 1 shows that the ENPOL® PBG7070 PBAT by itself has a similar % ash content, but significantly higher crystallization temperature (therefore a higher crystallization rate) as compared to the ECOFLEX® F CI 200 PBAT homopolymer. In order to facilitate making blown films with the

ECOFLEX® F CI 200, it was necessary to blend in talc. The data in Table 1 shows ECOFLEX® F C 1200 blended with 8% PLA and 1-3% talc as a nucleating agent. Addition of PLA by itself did not change the crystallization temperature of the ECOFLEX® F CI 200 but addition of just 1-3% talc increased the crystallization temperature of the ECOFLEX® F CI 200 significantly. However, blown films prepared from these foiTnulations had very high % Haze values (48-52%) indicating poor optical clarity. Addition of 8% PLA to ENPOL® PBG7070 slightly lowered the blown film's crystallization temperature but the % Haze was also very low indicating that the film had much better optical clarity as compared to the

ECOFLEX® F C1200/PLA/talc blends. The results indicated that the ENPOL® PBG7070 material when blended with PLA produced biodegradable films with very low % Haze (16%) and high crystallization rates which would be an advantage for packaging film applications.

[0070] Example 2. Preparation of a PBAT/PLA Low Haze Film Masterbatch A masterbatch used to produce low haze PBAT/PLA films can be prepared by combining 60-70% ENPOL^® PBG7070 with 30-40% INGEO^® 4032D or other equivalent PLA material and 1-2% of a fatty acid amide such as Erucamide. The materials are melt blended together using a twin screw extruder having the following heated zone temperatures from feed to die: 170°C/l70°C/170^oC/170^oC/160^oC /170°C/160^oC/160^oC/170^oC/160°C. Rpm speed of the twin screw extruder can be set to 500 with a torque of 80 Nm. Die pressure will be approximately 1800psi. The materials are then extruded, cooled and pelletized. To prepare a low haze film, the masterbatch pellets are combined or melt blended with 70-80% by weight ENPOL^® PBG7070 and extrusion blow molded into a 2 mil film. The % Haze of the film so produced would be approximately 16%.

[0071] Unless otherwise expressly specified, all of the numerical ranges, amounts, values and percentages, such as those for amounts of materials, elemental contents, times and temperatures of reaction, ratios of amounts, and others, in the following portion of the specification and attached claims may be read as if prefaced by the word "about" even though the term "about" may not expressly appear with the value, amount, or range. Accordingly, unless indicated to the contrary, the numerical parameters set forth in the following specification and attached claims are approximations that may vary depending upon the desired properties sought to be obtained by the present invention. At the very least, and not as an attempt to limit the application of the doctrine of equivalents to the scope of the claims, each numerical parameter should at least be construed in light of the number of reported significant digits and by applying ordinary rounding techniques.

[0072] Notwithstanding that the numerical ranges and parameters setting forth the broad scope of the invention are approximations, the numerical values set forth in the specific examples are reported as precisely as possible. Any numerical value, however, inherently contains error necessarily resulting from the standard deviation found in its underlying respective testing measurements. Furthermore, when numerical ranges are set forth herein, these ranges are inclusive of the recited range end points (i.e., end points may be used). When percentages by weight are used herein, the numerical values reported are relative to the total weight.

[0073] Also, it should be understood that any numerical range recited herein is intended to include all sub-ranges subsumed therein. For example, a range of "1 to 10" is intended to include all sub-ranges between (and including) the recited minimum value of 1 and the recited maximum value of 10, that is, having a minimum value equal to or greater than 1 and a maximum value of equal to or less than 10. The terms "one," "a," or "an" as used herein are intended to include "at least one" or "one or more," unless otherwise indicated.

[0074] Any patent, publication, or other disclosure material, in whole or in part, that is said to be incorporated by reference herein is incorporated herein only to the extent that the incorporated material does not conflict with existing definitions, statements, or other disclosure material set forth in this disclosure. As such, and to the extent necessary, the disclosure as explicitly set forth herein supersedes any conflicting material incorporated herein by reference. Any material, or portion thereof, that is said to be incorporated by reference herein, but which conflicts with existing definitions, statements, or other disclosure material set forth herein will only be incorporated to the extent that no conflict arises between that incorporated material and the existing disclosure material.

[0075] Unless otherwise defined, all technical and scientific terms used herein have the same meaning as commonly understood by one of ordinary skill in the art to which this invention belongs. Although methods and materials similar or equivalent to those described herein is used in the practice or testing of the present invention, suitable methods and materials are described below. All publications, patent applications, patents, and other references mentioned herein are incorporated by reference in their entirety. In case of conflict, the present specification, including definitions, will control. In addition, the materials, methods, and examples are illustrative only and not intended to be limiting.

[0076] All of the features disclosed in this specification may be combined in any combination. Each feature disclosed in this specification may be replaced by an alternative feature serving the same, equivalent, or similar purpose. Thus, unless expressly stated otherwise, each feature disclosed is only an example of a generic series of equivalent or similar features.

[0077] From the above description, one skilled in the art can easily ascertain the essential characteristics of the present invention, and without departing from the spirit and scope thereof, can make various changes and modifications of the invention to adapt it to various usages and conditions. Thus, other embodiments are also within the scope of the following claims.

[0078] While this invention has been particularly shown and described with references to preferred embodiments thereof, it will be understood by those skilled in the art that various changes in form and details may be made therein without departing from the scope of the invention encompassed by the appended claims.

Claims

CLAIMS What is claimed is:

1. A polymer film composition comprising a blend of a polybutylene adipate- terephthalate, polylactic acid and an amide wax wherein the blend has a percent Haze < 20%, a crystallization temperature of at least 80°C and a percent ash content of < 0.6%.

2. The polymer film composition of Claim 1 , wherein the concentration of the polybutylene adipate-terephthalate is between about 89% and 92%> of the total polymer composition weight.

3. The composition of any one of the preceding claims, wherein the

composition does not contain calcium carbonate, talc or boron nitride.

4. The composition of any one of the preceding claims, wherein the amount of the polylactic acid in the polymer composition is 5% to 11% by weight of the polymer composition.

5. The composition of any one of the preceding claims, wherein the amount of the polylactic acid in the polymer composition is 6% to 10% by weight of the polymer composition.

6. The composition of any one of the preceding claims, wherein the

composition contains one or more additives wherein the additive is not calcium carbonate, talc or boron nitride.

7. The composition of any one of the preceding claims, wherein at least one polymer in the composition is biodegradable.

8. A masterbatch composition for a making low haze polymer film comprising a polybutylene-adipate terephthalate polymer, a polylactic acid polymer and a fatty acid amide in the ratio of 49/27/1.

9. The composition of any one of Claims 1-8, wherein the polybutylene- adipate-terephthalate is ENPOL^® PGB7070.

10. A method of preparing a polybutylene adipate-terephthalate, polylactic acid and amide wax blend, comprising drying the polylactic acid for four hours at 80°C then melt blending the polymers and amide wax together and pelletizing the blend to make a homogeneous blend pellet wherein the blend has a percent Haze < 20%, a crystallization temperature of at least 80°C and a percent ash content of < 0.6%.

11. A method of making a low haze film article comprising extrusion blow

molding a polymer composition of polybutylene adipate-terephthalate, polylactic acid and an amide wax.

12. A method of preparing a polybutylene adipate-terephthalate and polylactic acid masterbatch comprising drying the polylactic for four hours at 80°C then melt blending with ENPOL^® PBG7070 wherein the weight ratio of polybutylene adipate-terephthalate to polylactic acid is 70/30 or 60/40 and pelletizing the blend to make a homogenous pellet.