Branched PLGA copolymers

Abstract

The present invention relates to branched PLGA copolymers, compositions comprising said branched PLGA copolymers, a process for preparing branched PLGA copolymers, and various articles and substrates comprising said branched PLGA copolymers or compositions comprising said branched PLGA copolymers.

Description

[0001] BRANCHED PLGA COPOLYMERS

[0002] FIELD OF THE INVENTION

[0003] The present invention relates to branched PLGA copolymers, processes for preparing branched PLGA copolymers and various uses of thereof.

[0004] BACKGROUND OF THE INVENTION

[0005] Paper and paperboard coated with barrier coatings enlarges the number of possible applications compared to non-coated paperboard. Such coatings can be used for example as barrier towards water, oils, aromas, grease and various gases. It can also be used for sealing purposes.

[0006] The demand for sustainable paper and paperboard packaging is increasing, because of the trend towards more sustainable packaging solutions driven by consumers, brand owners and retailers.

[0007] Polyethylene (PE) is the most commonly used material as a barrier coating; however, this polymer is not biodegradable, and therefore its use in paper packaging will limit its compostability and biodegradablility. Other resins, used to a lesser extent, falling in the same category are Polyethylene Terephthalate (PET) and Polypropylene (PP) present similar problems

[0008] Paper board coated with biobased barrier coatings typically are repulpable, recyclable, compostable and biodegradable. Polylactic Acid (PLA) is most commonly used as biobased alternative towards PE.

[0009] PLA is a linear polymer with a relative low melt strength, which makes processes such as film blowing, extrusion coating, and extrusion stretch blowing more difficult. In addition, this polymer has poor barrier properties.

[0010] In view of the above, there remains a constant need in the art to provide polymer materials with improved properties such as better melt strength and improved barrier properties.

[0011] Accordingly, it is an object of the present invention to provide polymer materials with improved properties. It is also an object of the invention to provide a polymer material that may overcome at least some of the above mentioned drawbacks of PLA.

[0012] SUMMARY OF THE INVENTION

[0013] It has now surprisingly been found that the above needs and objectives can be attained either individually or in any combination by a branched PLGA copolymer as defined herein. A first aspect of the present invention provides a branched poly(lactide-co-glycolide) (PLGA) polymer. In some embodiments, the present invention provides a branched poly(lactide-co- glycolide) (PLGA) polymer characterised by having a weight average molecular weight Mw of at least 15.000 g / mol, such as at least 25.000 g / mol. In some embodiments, the present invention provides a branched poly(lactide-co-glycolide) (PLGA) polymer characterised by having a weight average molecular weight Mw of at least 15 kg / mol, and a Mz / Mn of at least 3.3.

[0014] A second aspect of the present invention provides a process for manufacturing a branched poly(lactide-co-glycolide) (PLGA) polymer comprising the steps of: a. contacting at least one PLGA, preferably as defined herein, with at least one branching agent, preferably as defined herein; b. thereby forming said branched PLGA, preferably as defined herein.

[0015] A third aspect of the invention provides a composition, preferably for coating a substrate, comprising a branched PLGA according to the first aspect of the invention or obtained with the process of the second aspect.

[0016] A fourth aspect of the invention provides a substrate coated with a branched PLGA according to the first aspect, or obtained with the process of the second aspect, or with a composition according to the third aspect of the invention.

[0017] A fifth aspect of the invention provides an article comprising a branched PLGA according to the first aspect of the invention, or obtained with the process of the second aspect; or a composition according to the third aspect of the invention, or a substrate according to the fourth aspect of the invention.

[0018] A sixth aspect of the invention provides the use of a branched PLGA according to the first aspect of the invention, or obtained by the process of the second aspect, or of a composition according to the third aspect of the invention for coating a substrate.

[0019] The present invention offers several important advantages. The melt strength of the branched PLGA of the invention is remarkably higher than that of non-branched PLGA, which means that the branched PLGA of the invention has better processability. In coating applications, this leads to a large decrease in neck-in, which in turn permits high draw-downs and high operating line speeds. Another very significant advantage is that the branched PLGA of the invention can be made and used in a highly manageable reactive extrusion process. In addition, the branched PLGA of the invention can be made in-line if desired, as part of a coating or other melt-processing operation.

[0020] The present inventors have surprisingly found that the branched PLGA according to the present invention is compostable; more in particular it is home compostable. This means that articles comprising the branched PLGA according to the present invention, compositions comprising said branched PLGA or substrates coated with the branched PLGA or coated with compositions comprising the branched PLGA of the present invention may also be compostable and more in particular home compostable.

[0021] DETAILED DESCRIPTION OF THE DRAWINGS

[0022] Figure 1 represents a graph plotting the haul-off force (mM) against the haul off speed (mm / s) of a strand of PLGA branched with varying amounts of a branching agent according to the invention, compared with PLGA that has not been branched as obtained in Example 2.

[0023] Figure 2 represents a graph plotting the haul-off force (mM) against the haul off speed (mm / s) of a strand of PLGA branched with varying amounts of a branching agent according to the invention, compared with PLGA that has not been branched, as obtained in Example 2.

[0024] Figure 3 represents a graph plotting the haul-off speed (mm / s) against the haul off force (mM) of a strand of PLGA branched with varying amounts of a branching agent according to the invention, compared with PLGA that has not been branched as obtained in Example 2.

[0025] Figure 4 represents a graph plotting the haul-off speed (mm / s) against the haul off force (mM) of a strand of PLGA branched with varying amounts of a branching agent according to the invention, compared with PLGA that has not been branched as obtained in Example 3.

[0026] Figure 5 represents a graph plotting the haul-off force (mM) against the haul off speed (mm / s) of a strand of PLGA branched with varying amounts of a branching agent according to the invention, compared with PLGA that has not been branched as obtained in Example 3.

[0027] Figure 6 represents a graph plotting the haul-off force (mM) against the haul off speed (mm / s) of a strand of PLGA branched with a branching agent according to the invention, compared with PLGA that has not been branched as obtained in Example 3.

[0028] DETAILED DESCRIPTION OF THE INVENTION

[0029] When describing the invention, the terms used are to be construed in accordance with the following definitions, unless a context dictates otherwise. Unless otherwise defined, all terms used in disclosing the invention, including technical and scientific terms, have the meaning as commonly understood by one of ordinary skill in the art to which this invention belongs. By means of further guidance, term definitions are included to better appreciate the teaching of the present invention.

[0030] In the following passages, different aspects of the invention are defined in more detail. Each aspect so defined may be combined with any other aspect or aspects unless clearly indicated to the contrary. In particular, any feature indicated as being preferred or advantageous may be combined with any other feature or features indicated as being preferred or advantageous.

[0031] Reference throughout this specification to “one embodiment” or “an embodiment” means that a particular feature, structure or characteristic described in connection with the embodiment is included in at least one embodiment of the present invention. Thus, appearances of the phrases “in one embodiment” or “in an embodiment” in various places throughout this specification are not necessarily all referring to the same embodiment, but may. Furthermore, the particular features, structures or characteristics may be combined in any suitable manner, as would be apparent to a person skilled in the art from this disclosure, in one or more embodiments. Furthermore, while some embodiments described herein include some but not other features included in other embodiments, combinations of features of different embodiments are meant to be within the scope of the invention, and form different embodiments, as would be understood by those in the art.

[0032] The terms "comprising", "comprises" and "comprised of' as used herein are synonymous with "including", "includes" or "containing", "contains", and are inclusive or open-ended and do not exclude additional, non-recited members, elements or method steps. It will be appreciated that the terms "comprising", "comprises" and "comprised of" as used herein comprise the terms "consisting of", "consists" and "consists of".

[0033] As used in the specification and the appended claims, the singular forms "a", "an," and "the" include plural referents unless the context clearly dictates otherwise. By way of example, "a step" means one step or more than one step.

[0034] Unless defined otherwise, all technical and scientific terms used herein have the same meaning as is commonly understood by one of skill in the art. All publications referenced herein are incorporated by reference thereto.

[0035] The recitation of numerical ranges by endpoints includes all intervening values between the lower and upper endpoints, as well as the recited endpoints. Intervening values may be integers or, where applicable, fractions, i.e., more broadly any real numbers such as any rational numbers. For instance: 1 to 5 can include 1 , 2, 3, 4 when referring to, for example, a number of elements, and can also include 1 .5, 2, 2.75 and 3.80, when referring to, for example, measurements. The recitation of endpoints also includes the end point values themselves (e.g. from 1.0 to 5.0 includes both 1.0 and 5.0). This applies to numerical ranges irrespective of whether they are introduced by the expression “from... to...” or the expression “between... and...” or another expression. Any numerical range recited herein is intended to include all sub-ranges subsumed therein. For example, each sub-range between any stated value in a stated range and any other stated value in that stated range is also specifically disclosed. Each sub-range between any stated value in a stated range and either the lower endpoint or the upper endpoint of the stated range is also specifically disclosed. The stated value may be an isolated value or an endpoint of a range subsumed by or overlapping with the stated range. For example, for a stated range with lower endpoint L1 and upper endpoint U1 (i.e., stated range L1-LI1) and a stated sub-range nested within the stated range with lower endpoint L2 and upper endpoint U2 (i.e., stated sub-range L2-LI2), also specifically disclosed are the subranges L1-L2, L1-U2, L2-U1 , and U2-U1.

[0036] The term "about" as used herein when referring to a measurable value such as a parameter, an amount, a temporal duration, and the like, is meant to encompass variations of + / -10% or less, preferably + / -5% or less, more preferably + / -1 % or less, of and from the specified value, insofar such variations are appropriate to perform in the disclosed invention. It is to be understood that the value to which the modifier "about" refers is itself also specifically, and preferably, disclosed.

[0037] Whenever the term “substituted” is used in the present invention, it is meant to indicate that one or more hydrogens on the atom indicated in the expression using “substituted” is replaced with a selection from the indicated group, provided that the indicated atom’s normal valency is not exceeded, and that the substitution results in a chemically stable compound. Where groups can be substituted, such groups may be substituted with one or more, and preferably one, two or three substituents.

[0038] Whenever the term “substituted” is used herein, it is meant to indicate that one or more hydrogen atoms on the atom indicated in the expression using “substituted” is replaced with a selection from the indicated group, provided that the indicated atom’s normal valence is not exceeded, and that the substitution results in a chemically stable compound, i.e. a compound that is sufficiently robust to survive isolation from a reaction mixture. Where groups can be substituted, such groups may be substituted with one or more, and preferably one, two or three substituents.

[0039] The term "alkyl" by itself or as part of another substituent refers to a hydrocarbyl group of formula CnH2n+i wherein n is a number greater than or equal to 1. Alkyl groups may be linear or branched and may be substituted as indicated herein. When a subscript is used herein following a carbon atom, the subscript refers to the number of carbon atoms that the named group may contain. For example, the term "Ci-ealkyl", as a group or part of a group, refers to a hydrocarbyl group of formula -CnH2n+i wherein n is a number ranging from 1 to 6. Thus, for example, “Ci-ealkyl” includes all linear or branched alkyl groups with between 1 and 6 carbon atoms, and thus includes methyl, ethyl, n-propyl, i-propyl, butyl and its isomers (e.g. n-butyl, i- butyl and t-butyl); pentyl and its isomers, hexyl and its isomers. For example, “Ci-salkyl” includes all linear or branched alkyl groups with between 1 and 5 carbon atoms, and thus includes methyl, ethyl, n-propyl, i-propyl, butyl and its isomers (e.g. n-butyl, i-butyl and t-butyl); pentyl and its isomers. For example, “Ci-4alkyl” includes all linear or branched alkyl groups with between 1 and 4 carbon atoms, and thus includes methyl, ethyl, n-propyl, i-propyl, butyl and its isomers (e.g. n-butyl, i-butyl and t-butyl). For example “Ci-3alkyl” includes all linear or branched alkyl groups with between 1 and 3 carbon atoms, and thus includes methyl, ethyl, n- propyl, i-propyl. A “substituted Ci-ealkyl" refers to a Ci-ealkyl group substituted with one or more substituent(s) (for example 1 to 3 substituent(s), for example 1 , 2, or 3 substituent(s)) at any available point of attachment.

[0040] The term “alkoxy", as a group or part of a group, refers to a group having the formula -ORbwherein Rbis Ci-ealkyl as defined herein above. Non-limiting examples of suitable alkoxy include methoxy, ethoxy, propoxy, isopropoxy, butoxy, isobutoxy, sec-butoxy, tert-butoxy, pentyloxy and hexyloxy.

[0041] The term “cycloalkyl”, as a group or part of a group, refers to a cyclic alkyl group, that is a monovalent, saturated, hydrocarbyl group having 1 or more cyclic structure. Cycloalkyl includes all saturated hydrocarbon groups containing 1 or more rings, including monocyclic or bicyclic groups. The further rings of multi-ring cycloalkyls may be either fused, bridged and / or joined through one or more spiro atoms. When a subscript is used herein following a carbon atom, the subscript refers to the number of carbon atoms that the named group may contain. For example, the term “Cs-scycloalkyl”, a cyclic alkyl group comprising from 3 to 8 carbon atoms. For example, the term “Cs-ecycloalkyl”, a cyclic alkyl group comprising from 3 to 6 carbon atoms. Examples of C3-i2cycloalkyl groups include but are not limited to cyclopropyl, cyclobutyl, cyclopentyl, cyclohexyl, cycloheptyl, cyclooctyl, bicycle[2.2.1]heptan-2yl, (1S,4R)- norbornan-2-yl, (1 R,4R)-norbornan-2-yl, (1S,4S)-norbornan-2-yl, (1 R,4S)-norbornan-2-yl.

[0042] The term “aryl”, as a group or part of a group, refers to a polyunsaturated, aromatic hydrocarbyl group having a single ring (i.e. phenyl) or multiple aromatic rings fused together (e.g. naphthyl), or linked covalently, wherein at least one ring is aromatic. The aromatic ring may optionally include one to two additional rings (either cycloalkyl, heterocyclyl or heteroaryl) fused thereto. Examples of suitable aryl include Ce- aryl, more preferably Ce-saryl. Non-limiting examples of Ce-i2aryl comprise phenyl; biphenylyl; biphenylenyl; or 1-or 2-naphthanelyl; 1-, 2-, 3-, 4-, 5- or 6-tetralinyl (also known as “1 ,2,3,4-tetrahydronaphthalene); 1-, 2-, 3-, 4-, 5-, 6-, 7- or 8- azulenyl, 4-, 5-, 6 or 7-indenyl, 4- or 5-indanyl, 5-, 6-, 7- or 8-tetrahydronaphthyl; 1 , 2,3,4- tetrahydronaphthyl; and 1 ,4-dihydronaphthyl; 1-, 2-, 3-, 4- or 5-pyrenyl. A “substituted aryl” refers to an aryl group having one or more substituent(s) (for example 1 , 2 or 3 substituent(s), or 1 to 2 substituent(s)), at any available point of attachment.

[0043] The term “aryloxy”, as a group or part of a group, refers to a group having the formula -ORgwherein Rgis aryl as defined herein above.

[0044] The term "arylalkyl", as a group or part of a group, means a alkyl as defined herein, wherein at least one hydrogen atom is replaced by at least one aryl as defined herein. Non-limiting examples of arylalkyl group include benzyl, phenethyl, dibenzylmethyl, methylphenylmethyl, 3- (2-naphthyl)-butyl, and the like.

[0045] The term “hydroxyl” or “hydroxy” as used herein refers to the group -OH.

[0046] The term “nitro” as used herein refers to the group -NO2.

[0047] The term "carboxy" or “carboxyl” or “hydroxycarbonyl” as used herein refers to the group -CO2H.

[0048] The term “aminocarbonyl” as used herein refers to the group -CO-NH2.

[0049] The term “alkyloxycarbonyl”, as a group or part of a group, refers to a group of formula - COO-Rb, wherein Rbis alkyl as defined herein.

[0050] The terms described above and others used in the specification are well understood to those skilled in the art. Preferred statements (features) and embodiments of the processes, formulations and uses of this invention are set herein below. Each statement and embodiment of the invention so defined may be combined with any other statement and / or embodiment unless clearly indicated to the contrary. In particular, any feature indicated as being preferred or advantageous may be combined with any other feature or features or statements indicated as being preferred or advantageous. Hereto, the present invention is in particular captured by any one or any combination of one or more of the below numbered statements and embodiments, with any other aspect and / or embodiment.

[0051] 1. A branched poly(lactide-co-glycolide) (PLGA) polymer characterised by having a weight average molecular weight Mw of at least 15 kg / mol, wherein the Mw is determined according to the methodology described in the example section. 2. The branched PLGA according to statement 1 , wherein said branched PLGA has a weight average molecular weight Mw of at least 19 kg / mol; preferably an Mw of at least 22 kg / mol; preferably an Mw of at least 25 kg / mol; preferably an Mw of at least 28 kg / mol; preferably an Mw of at least 30 kg / mol; preferably an Mw of at least 35 kg / mol; preferably an Mw of at least 38 kg / mol.

[0052] 3. The branched PLGA according of statements 1 or 2, wherein said branched PLGA has a weight average molecular weight Mw of at most 2 000 kg / mol; preferably an Mw of at most 1 500 kg / mol; preferably an Mw of at most 1 000 kg / mol; preferably an Mw of at most 900 kg / mol.

[0053] 4. The branched PLGA according to any one of statements 1 to 3, wherein said branched PLGA has a weight average molecular weight Mw of from 15 kg / mol to 2 000 kg / mol; preferably an Mw of from 19 kg / mol to 1 500 kg / mol; preferably Mw of from 22 kg / mol to 1 300 kg / mol; preferably Mw of from 25 kg / mol to 1 200 kg / mol; preferably Mw of from 28 kg / mol to 1 000 kg / mol.

[0054] 5. The branched PLGA according to any one of the preceding statements, wherein said branched PLGA comprises at least 10.0 wt% of glycolide based on the total weight of the branched PLGA; preferably the branched PLGA comprises at least 12.0 wt% of glycolide; preferably the branched PLGA comprises at least 15.0 wt% of glycolide based on the total weight of the branched PLGA.

[0055] 6. The branched PLGA according to any one of the preceding statements, wherein said branched PLGA comprises at most 99.0 wt% of glycolide based on the total weight of the branched PLGA; preferably the branched PLGA comprises at most 98.0 wt% of glycolide; preferably the branched PLGA comprises at most 97.0 wt% of glycolide; preferably the branched PLGA comprises at most 96.0 wt% of glycolide based on the total weight of the branched PLGA.

[0056] 7. The branched PLGA according to any one of the preceding statements, wherein said branched PLGA comprises from 10.0 wt% to 99.0 wt% of glycolide based on the total weight of the branched PLGA; preferably the branched PLGA comprises from 12.0 wt% to 98.0 wt% of glycolide; preferably the branched PLGA comprises from 15.0 wt% to 98.0% of glycolide; preferably the branched PLGA comprises from 15.0 wt% to 97.0 wt% of glycolide; preferably the branched PLGA comprises from 15.0 wt% to 96.0 wt% of glycolide based on the total weight of the branched PLGA. 8. The branched PLGA according to any one of the preceding statements, wherein said branched PLGA has a Mz / Mn value of at least 3.3; preferably a Mz / Mn value of at least 3.4; preferably a Mz / Mn value of at least 3.5, preferably a Mz / Mn value of at least 3.7.

[0057] 9. The branched PLGA according to any one of the preceding statements, wherein said branched PLGA has a Mz / Mn value of at most 14.5; preferably a Mz / Mn value of at most 14.3; preferably a Mz / Mn value of at most 14.1 ; preferably a Mz / Mn value of at most 13.9; preferably a Mz / Mn value of at most 13.6, preferably a Mz / Mn value of at most 13.5.

[0058] 10. The branched PLGA according to any one of the preceding statements, wherein said branched PLGA has a Mz / Mn value of from 3.3 to 14.5; preferably a Mz / Mn value of from 3.3 to 14.3; preferably a Mz / Mn value of from 3.3 to 14.1 ; preferably a Mz / Mn value of from 3.3 to 14.0; preferably a Mz / Mn value of from 3.4 to 13.8; preferably a Mz / Mn value of from 3.5 to 13.6, preferably of from 3.7 to 13.5.

[0059] 11. The branched PLGA according to any one of the preceding statements, wherein the branched PLGA has an Mz / Mw value of more than 1.0, such as at least 1.1.

[0060] 12. The branched PLGA according to any one of the preceding statements, wherein the branched PLGA has an Mz / Mw value of at least 1 .2; preferably Mz / Mw value of at least 1.3; preferably Mz / Mw value of at least 1.5; preferably at least 1.6; preferably at least 1.8.

[0061] 13. The branched PLGA according to any one of the preceding statements, wherein the branched PLGA has an Mz / Mw of at most 22.0; preferably Mz / Mw of at most 21.5; preferably Mz / Mw of at most 20.0; preferably Mz / Mw of at most 19.5; preferably Mz / Mw of at most 18.5; preferably Mz / Mw of at most 18.0.

[0062] 14. The branched PLGA according to any one of the preceding statements, wherein said branched PLGA has a Mz / Mw value of from 1.1 to 22.0, or from 1.2 to 19.5; preferably a Mz / Mw value of from 1.3 to 18.5; preferably a Mz / Mw value of from 1.5 to 18.0, preferably a Mz / Mw value of from 1.6 to 17.5, preferably a Mz / Mw value of from 1.8 to 17.5.

[0063] 15. The branched PLGA according to any one of the preceding statements, wherein the branched PLGA has a melt flow index of from 1.0 to 300.0 g / 10 min as determined according to ISO1133 at 210 °C and under a load of 2.16 kg.

[0064] 16. The branched PLGA according to any one of the preceding statements, wherein the branched PLGA has a melt flow index of from 1.0 to 100.0 g / 10 min as determined according to ISO1133 at 210 °C and under a load of 2.16 kg; preferably a melt flow index of from 1.5 to 90.0 g / 10 min; preferably a melt flow index of from 2.0 to 80.0 g / 10 min; preferably a melt flow index of from 1.0 to 75.0 g / 10 min; preferably a melt flow index of from 2.0 to 65.0 g / 10 min; preferably a melt flow index of from 2.5 to 60.0 g / 10 min. 17. A branched poly(lactide-co-glycolide) (PLGA) polymer according to any one of the preceding statements, obtained by reacting: at least one poly(lactide-co-glycolide) (PLGA1) polymer; with at least one branching agent.

[0065] 18. The branched PLGA according to any one of the preceding statements, wherein said PLGA1 comprises at least 15.0 wt% of glycolide based on the total weight of the PLGA1 ; preferably the PLGA1 comprises at least 16.0 wt% of glycolide; preferably the PLGA1 comprises at least 17.0 wt% of glycolide based on the total weight of the PLGA1.

[0066] 19. The branched PLGA according to any one of the preceding statements, wherein said at least one PLGA1 comprises at most 99.0 wt% of glycolide based on the total weight of the PLGA1 ; preferably the PLGA1 comprises at most 98.0 wt% of glycolide; preferably the PLGA1 comprises at most 97.0 wt% of glycolide; preferably the PLGA1 comprises at most 96.0 wt% of glycolide based on the total weight of the PLGA1.

[0067] 20. The branched PLGA according to any one of the preceding statements, wherein said at least one PLGA1 comprises from 15.0 wt% to 99.0 wt% of glycolide based on the total weight of the PLGA1 ; preferably the PLGA1 comprises from 16.0 wt% to 98.0 wt% of glycolide; preferably the PLGA1 comprises from 17.0 wt% to 98.0% of glycolide; preferably the PLGA1 comprises from 17.0 wt% to 97.0 wt% of glycolide; preferably the PLGA1 comprises from 17.0 wt% to 96.0 wt% of glycolide based on the total weight of the PLGA1.

[0068] 21. The branched PLGA according to any one of the preceding statements, wherein said at least one PLGA1 has a weight average molecular weight Mw of at least 1 kg / mol; preferably an Mw of at least 3 kg / mol; preferably an Mw of at least 5 kg / mol; preferably an Mw of at least 8 kg / mol; preferably an Mw of at least 10 kg / mol; preferably an Mw of at least 15 kg / mol.

[0069] 22. The branched PLGA according to any one of the preceding statements, wherein said at least one PLGA1 has a weight average molecular weight Mw of at most 500 kg / mol; preferably an Mw of at most 400 kg / mol; preferably an Mw of at most 300 kg / mol; preferably an Mw of at most 200 kg / mol; preferably an Mw of at most 150 kg / mol.

[0070] 23. The branched PLGA according to any one of the preceding statements, wherein said at least one PLGA1 has a weight average molecularweight Mw of from 1 kg / mol to 500 kg / mol; preferably an Mw of from 3 kg / mol to 400 kg / mol; preferably an Mw of from 5 kg / mol to 300 kg / mol;; preferably an Mw of from 10 kg / mol to 300 kg / mol; preferably an Mw of from 10 kg / mol to 200 kg / mol; preferably an Mw of from 15 kg / mol to 150 kg / mol. 24. The branched PLGA according to any one of the preceding statements, wherein said at least one PLGA1 has a melt flow index of from 0.1 to 200.0 g / 10 min as determined according to ISO1133 at 210 °C and under a load of 2.16 kg; preferably a melt flow index of from 0.5 to 180.0 g / 10 min; preferably a melt flow index of from 0.8 to 150.0 g / 10 min; preferably a melt flow index of from 1 .0 to 120.0 g / 10 min; preferably a melt flow index of from 1.5 to 100.0 g / 10 min; preferably a melt flow index of from 2.0 to 80.0 g / 10 min; preferably a melt flow index of from 2.5 to 75.0 g / 10 min; preferably a melt flow index of from 3.0 to 70.0 g / 10 min; or a melt flow index of from 0.1 to 200.0 g / 10 min as determined according to ISO1133 at 230 °C and under a load of 2.16 kg; preferably a melt flow index of from 0.5 to 180.0 g / 10 min; preferably a melt flow index of from 0.8 to 150.0 g / 10 min; preferably a melt flow index of from 1.0 to 120.0 g / 10 min; preferably a melt flow index of from 1.5 to 100.0 g / 10 min; preferably a melt flow index of from 2.0 to 80.0 g / 10 min; preferably a melt flow index of from 2.5 to 75.0 g / 10 min; preferably a melt flow index of from 3.0 to 70.0 g / 10 min.

[0071] 25. The branched PLGA according to any one of the preceding statements, wherein said at least one branching agent is selected from the group consisting of an epoxide- functionalized branching agent, a peroxide-functionalized branching agent, an anhydride- functionalized branching agent, an isocyanate-functional ized branching agent, an oxazoline branching agent, an oxazine branching agent, or a combination thereof.

[0072] 26. The branched PLGA according to any one of the preceding statements, wherein said at least one branching agent is an epoxide-functionalized branching agent; preferably the branching agent is an epoxy functional styrene-acrylate copolymer.

[0073] 27. The branched PLGA according to any one of the preceding statements, wherein the epoxide-functionalized branching agent has a number average molecular weight Mn of from 6.0 to 8.5 kg / mol.

[0074] 28. The branched PLGA according to any one of the preceding statements, wherein the epoxide-functionalized branching agent has at least 3 epoxy groups.

[0075] 29. The branched PLGA according to any one of the preceding statements, wherein said at least one branching agent is a peroxide-functionalized branching agent; preferably said peroxide-functionalized branching agent is a cyclic peroxide or a linear peroxide.

[0076] 30. The branched PLGA according to any one of the preceding statements, wherein said branched PLGA is obtained by reacting at least one PLGA1 ; with at least 0.10 wt% of at least one branching agent, based on the total weight of the reaction mixture; preferably at least 0.15 wt%; preferably at least 0.20 wt%; preferably at least 0.25 wt%; preferably at least 0.30 wt%; preferably at least 0.35 wt%; preferably at least 0.40 wt%; preferably at least 0.45 wt% of at least one branching agent, based on the total weight of the reaction mixture. The branched PLGA according to any one of the preceding statements, wherein said branched PLGA is obtained by reacting at least one PLGA1 ; with at most 5.00 wt% of at least one branching agent, based on the total weight of the reaction mixture; preferably at most 4.50 wt%; preferably at most 4.00 wt%; preferably at most 3.50 wt%; preferably at most 3.00 wt% of at least one branching agent, based on the total weight of the reaction mixture. The branched PLGA according to any one of the preceding statements, wherein said branched PLGA is obtained by reacting at least one PLGA1 ; with from 0.10 wt% to 5.00 wt% of at least one branching agent, based on the total weight of the reaction mixture; preferably from 0.15 wt% to 4.50 wt%; preferably from 0.20 wt% to 4.00 wt%; preferably from 0.25 wt% to 3.00 wt%; preferably from 0.30 wt% to 2.50 wt%; preferably from 0.35 wt% to 2.50 wt%; of at least one branching agent, based on the total weight of the reaction mixture. The branched PLGA according to any one of the preceding statements, wherein said branched PLGA is obtained by reacting at least one PLGA1 with at least one branching agent in a weight ratio of PLGA1 branching agent of from 99.90:0.10 to 95.00:5.00; preferably a weight ratio of 99.85:0.15 to 96.00:4.00; preferably a weight ratio of from 99.80:0.20 to 97.50:2.50; preferably a weight ratio of from 99.70:0.30 to 97.00:3.00; preferably a weight ratio of 99.60:0.40 to 96.50:3.50; preferably a weight ratio of from 99.50:0.50 to 96.00:4.00. Process for producing a branched poly(lactide-co-glycolide) (PLGA) polymer comprising the step of a. contacting at least one poly(lactide-co-glycolide) (PLGA1), with at least one branching agent; b. thereby forming said branched PLGA. Process according to statement 34, for the manufacture of a branched PLGA according to any one of the preceding statements; wherein the PLGA1 is as defined in any one of the preceding statements wherein the branching agent is as defined in any one of the preceding statements. Process for producing a branched poly(lactide-co-glycolide) (PLGA) polymer having a weight average molecular weight Mw of at least 15 kg / mol and a Mz / Mn of at least 3.3, comprising the step of: melt blending in an extruder a precursor composition comprising at least one poly(lactide-co-glycolide) (PLGA1) having a melt flow index of from 0.1 to 200.0 g / 10 min as determined according to ISO1133 at 210 °C and under a load of 2.16 kg, or having a melt flow index of from 0.1 to 200.0 g / 10 min as determined according to ISO1133 at 230 °C and under a load of 2.16 kg, and comprising from 15.0 wt% to 99.0 wt% of glycolide based on the total weight of the PLGA1 , with at least one branching agent, thereby obtaining said branched PLGA polymer, wherein the Mw, Mz, and Mn are determined according to the methodology described in the example section. The process according to any one of the preceding statements, wherein said precursor composition comprises at least 90.0 wt% of poly(lactide-co-glycolide) (PLGA1), based on the total weight of the precursor composition, preferably at least 95.0 wt%, preferably at least 97.0 wt% of poly(lactide-co-glycolide) (PLGA1), preferably at least 99.0 wt% of poly(lactide-co-glycolide) (PLGA1), based on the total weight of the precursor composition, and preferably wherein said precursor composition consists of said poly(lactide-co- glycolide) (PLGA1). Process according to any one of the preceding statements, wherein said precursor composition comprises less than 10.0 wt% polyglycolide (PGA), preferably less than 5.0 wt% PGA, preferably less than 1.0 wt% PGA, based on the total weight of the precursor composition. The process according to any one of the preceding statements, wherein said melt blending is performed in the absence of polyglycolide (PGA). The process according to any one of the preceding statements, wherein the weight ratio of said at least one PLGA1 and said at least one branching agent during said melt blending step ranges from 99.90:0.10 to 95.00:5.00, or a weight ratio of 99.85:0.15 to 96.00:4.00; or a weight ratio of from 99.80:0.20 to 97.50:2.50; or a weight ratio of from 99.70:0.30 to 97.00:3.00; or a weight ratio of 99.60:0.40 to 96.50:3.50; or a weight ratio of from 99.50:0.50 to 96.00:4.00. 41. Process according to any one of the preceding statements, wherein said contacting step comprises melt blending the at least one PLGA1 with the at least one branching agent.

[0077] 42. Process according to any one of the preceding statements, wherein said contacting step comprises melt blending the at least one PLGA1 with the at least one branching agent at a temperature ranging from 150 °C to 250 °C; preferably at a temperature ranging from 160 °C to 230 °C, or preferably at a temperature ranging from 190°C to 230°C.

[0078] 43. The process according to any one of the preceding statements, wherein said precursor composition is melt blended with the at least one branching agent at a temperature of least 190°C, preferably at a temperature ranging from 190°C to 230°C.

[0079] 44. Process according to any one of the preceding statements, wherein said contacting step comprises melt blending the at least one PLGA1 with the at least one branching agent for at least 35 seconds, preferably for at least 50 seconds.

[0080] 45. Process according to any one of the preceding statements, wherein said contacting step comprises melt blending the at least one PLGA1 with the at least one branching agent in an extruder.

[0081] 46. Process according to any one of the preceding statements, wherein said contacting step comprises melt blending the at least one PLGA with the at least one branching agent in an extruder at a temperature of at least 150 °C, and for at least 30 seconds, or at a temperature of at least 190 °C, and for at least 35 seconds, preferably for at least 50 seconds.

[0082] 47. The process according to any one of the preceding statements, wherein said PLGA1 is as defined according to any one of the preceding statements.

[0083] 48. The process according to any one of the preceding statements, wherein said branched is as defined according to any one of the preceding statements.

[0084] 49. A branched PLGA obtainable with (produced by) a process according to any one of statements 34 to 48.

[0085] 50. A composition, preferably for coating a substrate, comprising a branched PLGA polymer characterised by having a weight average molecular weight Mw of at least 15 kg / mol, wherein the Mw is determined according to the methodology described in the example section.

[0086] 51. A composition, preferably for coating a substrate, comprising a branched PLGA according to any one of the statements 1 to 33 and 49. A composition, preferably for coating a substrate, comprising a branched PLGA produced by the process of any one of the statements 34 to 48. The composition according to any one of the preceding statements, wherein the composition comprises branched PLGA in an amount of between 10.0 and 95.0 wt%, preferably 15.0 and 80.0 wt%, preferably between 20.0 and 70.0 wt%, with wt% based on the total weight of the composition. The composition according to any one of the preceding statements, wherein the composition further comprises at least one polymer; preferably the at least one polymer is selected from the group comprising poly(butylene adipate-co-terephthalate) (PBAT), polylactic acid (PLA), polycaprolactone (PCL), polyhydroxyalkanoates (PHAs), poly(butylene succinate) (PBS), poly(butylene succinate-co-adipate) (PBSA), thermoplastic starch (TPS), polyvinyl acetate (PVAc), and mixtures thereof. The composition according to any one of the preceding statements, wherein the composition further comprises at least one polymer in an amount of 1.0 and 50.0 wt%, preferably 2.5 and 40.0 wt%, preferably between 5.0 and 30.0 wt%, preferably between 1 .0 and 20.0 wt% with wt% based on the total weight of the composition. The composition according to any one of the preceding statements, wherein the composition further comprises at least one plasticizer; preferably the at least one plasticizer is selected from the group comprising polyethylene glycol (PEG), epoxidized vegetable oils from soybean oil, linseed oil, castor-oil, sunflower oil, citrate esters, adipates, phthalates, sorbitol, glycerol, fatty acid esters (FAEs) and mixtures thereof. The composition according to any one of the preceding statements, wherein the composition further comprises at least one polymer in an amount of 1.0 and 20.0 wt%, preferably 2.0 and 18.0 wt%, more preferably between 2.0 and 15.0 wt%, preferably between 2.5 and 15.0 wt% with wt% based on the total weight of the composition. The composition according to any one of the preceding statements, wherein the composition further comprises at least one stabilizer; preferably the composition comprises at least one stabilizer in an amount of 0.10 and 2.00 wt%, preferably 0.20 and 1.80 wt%, more preferably between 0.20 and 1.50 wt%, preferably between 0.25 and 1.5 wt%, with wt% based on the total weight of the composition. The composition according to any one of the preceding statements, wherein the composition further comprises at least one additive selected from the group comprising lubricants, extender oils, pH controlling substances, release agents, colorants, reinforcing fillers, non-reinforcing fillers, fibrous materials, nucleating agents, catalyst quenchers, slip and antiblocking agents, and combinations thereof.

[0087] 60. A substrate coated with a branched PLGA polymer, wherein said branched PLGA polymer is characterised by having a weight average molecular weight Mw of at least 15 kg / mol, wherein the Mw is determined according to the methodology described in the example section.

[0088] 61 . A substrate coated with a branched PLGA according to any one of statements 1-33 and 49 or with a composition according to any one of the preceding statements 50 to 59.

[0089] 62. The substrate according to any one of the preceding statements, wherein said substrate is selected from the group comprising lignocellulosic substrate, cellulosic substrate, a textile, a metal and a composite material.

[0090] 63. The substrate according to any one of the preceding statements, wherein said substrate is a cellulosic substrate or a lignocellulosic substrate.

[0091] 64. The substrate according to any one of the preceding statements, wherein said lignocellulosic or cellulosic substrate is selected from the group comprising paper, paperboard, cartonboard wood and fibreboard, textile material, a material based on paperpulp; preferably paper or paperboard.

[0092] 65. The substrate according to any one of the preceding statements, wherein said substrate has a weight prior to coating of at least 0.5 g / m2, such as at least 1 g / m2; or at least 10.0g / m2; or at least 25.0 g / m2.

[0093] 66. The substrate according to any one of the preceding statements, wherein said coated substrate has a coating weight ranging from 1 to 50.0 g / m2; preferably a weight of from 2.0 to 40.0 g / m2; preferably a weight of from 2.5 to 35.0 g / m2; preferably a weight of from 3.0 to 30.0 g / m2.

[0094] 67. The substrate according to any one of the preceding statements, wherein said substrate is coated by a process selected from the group comprising extrusion coating, bar and knife coating, lamination coating, suspension coating, emulsion coating and dispersion coating.

[0095] 68. The substrate according to any one of the preceding statements, wherein the substrate is compostable and / or biodegradable.

[0096] 69. The substrate according to any one of the preceding statements, wherein the substrate is an industrially compostable material or a home compostable material. 70. The substrate according to any one of the preceding statements, wherein the substrate is an industrially compostable material that conforms to EN 13432 and / or ASTM D6400 standards.

[0097] 71. The substrate according to any one of the preceding statements, wherein the substrate is a home compostable material that conforms to NF T51-800 (2015) and / or AS 5810 (2010) standards.

[0098] 72. The substrate according to any one of the preceding statements, wherein the substrate is recyclable.

[0099] 73. A process for coating a substrate according to any one of the preceding statements, said process comprising the step of coating of a branched PLGA according to any one of statements 1 to 33 and 49, or of a composition according to any one of statements 50 to 59 onto at least one surface of the substrate to form a coated substrate.

[0100] 74. Process according to statement 73, when said coating is performed by extrusion coating, lamination coating, or suspension coating.

[0101] 75. An article comprising a branched PLGA according to any one of statements 1 to 33 and 49, or a composition according to any one of statements 50 to 59, or a substrate according to any one of statements 60 to 72.

[0102] 76. The article according to the previous statement, wherein said article is a container, bottle, packaging material, film, foamed material, bag or wrapping material.

[0103] 77. The article according to any one of the preceding statements, wherein the article is biodegradable; preferably compostable; more preferably home compostable.

[0104] 78. The article according to any one of the preceding statements, wherein the article is an industrially compostable material or a home compostable material.

[0105] 79. The article according to any one of the preceding statements, wherein the article is an industrially compostable material that conforms to EN 13432 and / or ASTM D6400 standards.

[0106] 80. The article according to any one of the preceding statements, wherein the article is a home compostable material that conforms to NF T51-800 (2015) and / or AS 5810 (2010) standards.

[0107] 81. Use of a branched PLGA polymer for coating a substate, wherein said branched PLGA polymer is characterised by having a weight average molecular weight Mw of at least 15 kg / mol, wherein the Mw is determined according to the methodology described in the example section.

[0108] 82. Use of a branched PLGA according to any one of statement 1 to 33 and 49, or a composition according to any one of statements 50 to 59 for coating a substrate.

[0109] 83. The use according to any one of statements 81-82, for coating a substrate as defined by any one of statements 62 to 72 by a process selected from the group comprising extrusion coating, bar and knife coating and lamination coating.

[0110] 84. Use of a branched PLGA according to any one of statements 1 to 33 and 49, or a composition according to any one of statements 50 to 59 for producing a film.

[0111] 85. Use of a branched PLGA according to any one of statements 1 to 33 and 49, or a composition according to any one of statements 50 to 59 for producing at least one layer in a multilayer film.

[0112] 86. The use according to any one of statements 84-85, wherein said film is produced by a process selected from cast film extrusion, blown film extrusion, injection stretch blow moulding, extrusion blow moulding and extrusion lamination, or combinations thereof.

[0113] Hereunder, particularities of the branched PLGA according to the invention will be discussed in more detail.

[0114] The present invention relates to a branched poly(lactide-co-glycolide) (PLGA) polymer characterised by having a weight average molecular weight Mw of at least 15 kg / mol, wherein the Mw is determined according to the methodology described in the example section.

[0115] The present invention also relates to a branched poly(lactide-co-glycolide) (PLGA) polymer characterised by having a weight average molecular weight Mw of at least 15 kg / mol, and a Mz / Mn of at least 3.3, wherein the Mw, Mz, and Mn are determined according to the methodology described herein, see in the example section.

[0116] The present invention also relates to a process for producing a branched poly(lactide-co- glycolide) (PLGA) polymer and the branched poly(lactide-co-glycolide) (PLGA) thereby obtained.

[0117] The terms “weight average molecular weight” or “Mw” as used herein as synonyms. Whenever reference is made herein to “weight average molecular weight” or “Mw” reference is made to the absolute molecular weight, which can be determined by Size Exclusion Chromatography (SEC) as explained in the example section.

[0118] Molecular weight measurements by SEC may be done in two ways: absolute SEC, which measures the true molecular weight of the polymer and relative SEC, which measures the molecular weight of the polymer relative to a calibration standard, for example polystyrene standard.

[0119] The terms “z average molecular weight” or “Mz” as used herein as synonyms. Whenever reference is made herein to “z average molecular weight” or “Mz” reference is made to the absolute z average molecular weight, which can be determined by Size Exclusion Chromatography (SEC) as explained in the example section.

[0120] The terms “number average molecular weight” or“Mn” as used herein as synonyms. Whenever reference is made herein to “number average molecular weight” or “Mn” reference is made to the absolute number average molecular weight, which can be determined by Size Exclusion Chromatography (SEC) as explained in the example section.

[0121] As used herein the term “branching” refers to the regular or irregular attachment of side chains to a polymer’s backbone chain. By analogy, the term “branched PLGA” as used herein refers to a PLGA backbone to which side chains have been attached.

[0122] BRANCHED PLGA

[0123] In some embodiments the branched PLGA according to the invention has a weight average molecular weight Mw of at least 17 kg / mol; preferably an Mw of at least 24 kg / mol; preferably an Mw of at least 27 kg / mol; preferably an Mw of at least 31 kg / mol; preferably an Mw of at least 34 kg / mol; preferably an Mw of at least 38 kg / mol; preferably an Mw of at least 41 kg / mol.

[0124] In some embodiments the branched PLGA according to the invention has a weight average molecular weight Mw of at most 2 000 kg / mol; preferably an Mw of at most 1 500 kg / mol; preferably an Mw of at most 1 300 kg / mol; preferably an Mw of at most 1 000 kg / mol; preferably of at most 900 kg / mol; preferably of at most 800 kg / mol; preferably of at most 700 kg / mol.

[0125] In some embodiments the branched PLGA according to the invention has a weight average molecular weight Mw of from 16 kg / mol to 2 000 kg / mol; preferably an Mw of from 17 kg / mol to 1 500 kg / mol; preferably Mw of from 24 kg / mol to 1 300 kg / mol; preferably Mw of from 27 kg / mol to 1 000 kg / mol; preferably Mw of from 31 kg / mol to 900 kg / mol; preferably Mw of from 34 kg / mol to 800 kg / mol; preferably Mw of from 38 kg / mol to 700 kg / mol.

[0126] In some embodiments the branched PLGA according to the present invention, has a Mz / Mn value of at least 3.3, such as at least 3.7.

[0127] In some embodiments the branched PLGA according to the invention has a weight average molecular weight Mw of from 16 kg / mol to 2 000 kg / mol; preferably an Mw of from 17 kg / mol to 1 500 kg / mol; preferably Mw of from 24 kg / mol to 1 300 kg / mol; preferably Mw of from 27 kg / mol to 1 000 kg / mol; preferably Mw of from 31 kg / mol to 900 kg / mol; preferably Mw of from 34 kg / mol to 800 kg / mol; preferably Mw of from 38 kg / mol to 700 kg / mol; and a Mz / Mn value of at least 3.3, preferably at least 3.7. In some embodiments the branched PLGA according to the present invention, has a Mz / Mn value of from 3.3 to 14.1 ; preferably a Mz / Mn value of from 3.4 to 14.0; preferably a d Mz / Mn value of from 3.5 to 13.8; preferably a Mz / Mn value of from 3.6 to 13.6.

[0128] In some embodiments the branched PLGA according to the invention has a weight average molecular weight Mw of from 16 kg / mol to 2 000 kg / mol; preferably an Mw of from 17 kg / mol to 1 500 kg / mol; preferably Mw of from 24 kg / mol to 1 300 kg / mol; preferably Mw of from 27 kg / mol to 1 000 kg / mol; preferably Mw of from 31 kg / mol to 900 kg / mol; preferably Mw of from 34 kg / mol to 800 kg / mol; preferably Mw of from 38 kg / mol to 700 kg / mol; and a Mz / Mn value of from 3.3 to 14.1 ; preferably a Mz / Mn value of from 3.4 to 14.0; preferably a Mz / Mn value of from 3.5 to 13.8; preferably a Mz / Mn value of from 3.6 to 13.6, preferably a Mz / Mn value of from 3.7 to 13.5.

[0129] The branched PLGA according to the present invention, wherein the branched PLGA has an Mw / Mn of at least 1.6; preferably Mw / Mn of at least 1.8; preferably Mw / Mn of at least 2.0; preferably Mw / Mn of at least 2.2; preferably Mw / Mn of at least 2.5; preferably Mw / Mn of at least 3.0.

[0130] In some embodiments the branched PLGA according to the invention has a weight average molecular weight Mw of from 16 kg / mol to 2 000 kg / mol; preferably an Mw of from 17 kg / mol to 1 500 kg / mol; preferably Mw of from 24 kg / mol to 1 300 kg / mol; preferably Mw of from 27 kg / mol to 1 000 kg / mol; preferably Mw of from 31 kg / mol to 900 kg / mol; preferably Mw of from 34 kg / mol to 800 kg / mol; preferably Mw of from 38 kg / mol to 700 kg / mol; and an Mw / Mn of at least 1 .6; preferably Mw / Mn of at least 1 .8; preferably Mw / Mn of at least 2.0; preferably Mw / Mn of at least 2.2; preferably Mw / Mn of at least 2.5; preferably Mw / Mn of at least 3.0.

[0131] It is preferred according to the present invention that the branched PLGA according to the invention has a Mz / Mw value of more than 1 .0, such as at least 1.1 ; preferably Mz / Mw value of at least 1 .4, preferably a Mz / Mw value of at least 1.6.

[0132] In some embodiments, the branched PLGA according to the invention has an Mz / Mw of at most 22.0, preferably at most 21.8; preferably Mz / Mw of at most 21.3; preferably Mz / Mw of at most 20.8; preferably Mz / Mw of at most 19.3; preferably Mz / Mw of at most 18.8; preferably Mz / Mw of at most 18.3. In some embodiments, the branched PLGA according to the invention has a Mz / Mw value of from 1.1 to 22.0; preferably a Mz / Mw value of from 1.1 to 20.8; preferably a Mz / Mw value of from 1.4 to 19.3; preferably a Mz / Mw value of from 1.4 to 18.8; preferably a Mz / Mw value of from 1.5 to 18.3, preferably a Mz / Mw value of from 1.6 to 17.5, preferably a Mz / Mw value of from 1.8 to 17.5.

[0133] In some embodiments the branched PLGA according to the invention has a weight average molecular weight Mw of from 16 kg / mol to 2 000 kg / mol; preferably an Mw of from 17 kg / mol to 1 500 kg / mol; preferably Mw of from 24 kg / mol to 1 300 kg / mol; preferably Mw of from 27 kg / mol to 1 000 kg / mol; preferably Mw of from 31 kg / mol to 900 kg / mol; preferably Mw of from 34 kg / mol to 800 kg / mol; preferably Mw of from 38 kg / mol to 700 kg / mol; and has an Mz / Mw value of at least 1.1 ; preferably Mz / Mw value of at least 1.4, preferably Mz / Mw value of at least 1.8.

[0134] In some embodiments the branched PLGA according to the invention has a weight average molecular weight Mw of from 16 kg / mol to 2 000 kg / mol; preferably an Mw of from 17 kg / mol to 1 500 kg / mol; preferably Mw of from 24 kg / mol to 1 300 kg / mol; preferably Mw of from 27 kg / mol to 1 000 kg / mol; preferably Mw of from 31 kg / mol to 900 kg / mol; preferably Mw of from 34 kg / mol to 800 kg / mol; preferably Mw of from 38 kg / mol to 700 kg / mol; and an Mz / Mw of at most 21.8; preferably Mz / Mw of at most 21.3; preferably Mz / Mw of at most 20.8; preferably Mz / Mw of at most 19.3; preferably Mz / Mw of at most 18.8; preferably Mz / Mw of at most 18.3.

[0135] In some embodiments the branched PLGA according to the invention has a weight average molecular weight Mw of from 16 kg / mol to 2 000 kg / mol; preferably an Mw of from 17 kg / mol to 1 500 kg / mol; preferably Mw of from 24 kg / mol to 1 300 kg / mol; preferably Mw of from 27 kg / mol to 1 000 kg / mol; preferably Mw of from 31 kg / mol to 900 kg / mol; preferably Mw of from 34 kg / mol to 800 kg / mol; preferably Mw of from 38 kg / mol to 700 kg / mol; and a Mz / Mw value of from 1.1 to 22.0, preferably from 1.1 to 20.8; preferably a Mz / Mw value of from 1 .4 to 19.3; preferably a Mz / Mw value of from 1 .4 to 18.8; preferably a Mz / Mw value of from 1.5 to 18.3, preferably from 1.6 to 17.5, preferably a Mz / Mw value of from 1.8 to 17.5.

[0136] Advantageously, the melt flow index of the branched PLGA according to the present invention is lower than that of a non-branched PLGA; this indicates that the branched PLGA of the invention has a higher viscosity than the corresponding non-branched PLGA.

[0137] In some embodiments, the branched PLGA according to the present invention is melt processable. As used herein, the term “melt processable” refers to the capacity of the branched PLGA to be processed by melting. Such processes may include but is not limited to extrusion, compression moulding, blow moulding, injection moulding.

[0138] In some other embodiments, the branched PLGA has a melt flow index of from 1.0 to 300.0 g / 10 min as determined according to ISO1133 at 210 °C and under a load of 2.16 kg.

[0139] In some other embodiments, the branched PLGA has a melt flow index of from 1.0 to 100.0 g / 10 min as determined according to ISO1133 at 210 °C and under a load of 2.16 kg.

[0140] In some embodiments the branched PLGA has a melt flow index of from 1.5 to 100.0 g / 10 min as determined according to ISO1133 at 210 °C and under a load of 2.16 kg; preferably a melt flow index of from 1 .9 to 95.0 g / 10 min; preferably a melt flow index of from 2.3 to 85.0 g / 10 min; preferably a melt flow index of from 2.5 to 77.0 g / 10 min; preferably a melt flow index of from 2.5 to 63.0 g / 10 min.

[0141] In some embodiments the branched PLGA according to the invention has a weight average molecular weight Mw of from 16 kg / mol to 2 000 kg / mol; preferably an Mw of from 17 kg / mol to 1 500 kg / mol; preferably Mw of from 24 kg / mol to 1 300 kg / mol; preferably Mw of from 27 kg / mol to 1 000 kg / mol; preferably Mw of from 31 kg / mol to 900 kg / mol; preferably Mw of from 34 kg / mol to 800 kg / mol; preferably Mw of from 38 kg / mol to 700 kg / mol; and a melt flow index of from 1.5 to 100.0 g / 10 min as determined according to ISO1133 at 210 °C and under a load of 2.16 kg; preferably a melt flow index of from 1.9 to 95.0 g / 10 min; preferably a melt flow index of from 2.3 to 85.0 g / 10 min; preferably a melt flow index of from 2.5 to 77.0 g / 10 min; preferably a melt flow index of from 2.5 to 63.0 g / 10 min.

[0142] In some embodiments, the present invention provides a branched PLGA, wherein said branched PLGA has a Mw of at least 15 kg / mol, such as at least 19 kg / mol; or at least 22 kg / mol; or at least 25 kg / mol; or at least 28 kg / mol; or at least 30 kg / mol; or at least 35 kg / mol; or at least 38 kg / mol, a Mz / Mn value of at least 3.3, or at least 3.4; or at least 3. or at least 3.6, or at least 3.7; and a Mz / Mw value of at least 1.2; or at least 1.3; or at least 1.5, or at least 1 .8, and optionally a Mw / Mn value of an Mw / Mn of at least 2.0, or at least 2.2, and optionally a melt flow index of from 2.0 to 80.0 g / 10 min, or a melt flow index of from 3.5 to 75.0 g / 10 min, wherein the Mw, Mn and Mz is determined according to the methodology described in the example section. In some embodiments, the present invention provides a branched PLGA, wherein said branched PLGA has a weight average molecular weight Mw of from 15 kg / mol to 2000 kg / mol; preferably an Mw of from 19 kg / mol to 1500 kg / mol; preferably Mw of from 22 kg / mol to 1300 kg / mol; preferably Mw of from 25 kg / mol to 1200 kg / mol; preferably Mw of from 28 kg / mol to 1000 kg / mol; and a Mz / Mn value of from 3.3 to 14.0; preferably from 3.4 to 13.8; preferably from 3.5 to

[0143] 13.6, preferably from 3.7 to 13.5, a Mz / Mw value of at least 1.2; or at least 1.3; or at least 1.5, or at least 1 .8, and optionally a Mw / Mn value of an Mw / Mn of at least 2.0, or at least 2.2, and optionally a melt flow index of from 2.0 to 80.0 g / 10 min, or a melt flow index of from 3.5 to 75.0 g / 10 min, wherein the Mw, Mn and Mz is determined according to the methodology described in the example section.

[0144] PLGA1

[0145] The term “PLGA” or “poly(lactide-co-glycolide)” or “PLGA copolymer” or “poly(lactide-co- glycolide) copolymer” or “PLGA1” are used herein as synonyms and refer to a polymer comprising lactide and glycolide.

[0146] When used herein the term PLGA1 intends to refer to the starting material, before branching. PLGA, i.e. the starting material PLGA1 , is a / / near copolymer that can be prepared at different ratios between its constituent monomers, lactic acid and glycolic acid according to methods that are well known to the skilled person. For example, by direct polycondensation of lactic acid and glycolic acid, optionally using coupling agents to obtain high molecular weight polymers; by dehydrative azeotropic condensation of lactic acid and glycolic acid; or by ring opening polymerization (ROP) of the dimer of lactic acid (lactide) and the dimer of glycolic acid (glycolide) or the dimer of lactic acid and glycolic acid (3-methyl glycolide) or mixtures thereof.

[0147] The ring opening polymerization may be conducted in the bulk (melt polymerization), or in solution according to methods that are known in the art using catalysts and reaction conditions customary for lactide polymerization. Ring opening polymerization reaction to produce PLGA1 may proceed using a variety of catalysts, such as those conventionally used in the synthesis of polylactic acid (PLA). Other suitable catalysts may be as powdered zinc, Lewis acids (e.g., zinc chloride and antimony trifluoride), or organometallic compounds. In some embodiments, the catalyst may be added in an amount ranging from 1 to 500 ppm based on the weight of the reaction; preferably an amount ranging from 20 to 100 ppm based on the wight of the reaction. A primary aliphatic alcohol (e.g., alcohols) may be used as initiator for the ROP reaction. In some embodiments, the initiator is added in an amount ranging from 200 to 20 000 ppm, based on the weight of the reaction.

[0148] The ROP polymerization may be carried out either in high vacuum or in inert atmosphere (e.g., in nitrogen). The amount and type of the catalyst and the temperature may determine the time required to produce the PLGA1. The ROP of lactide and glycolide may be performed in bulk (melt or solid polymerization) and be carried out at temperatures ranging between 130 °C and 250 °C over a period of 2-6hr.

[0149] In certain embodiments, the lactide suitable to produce the PLGA1 according to the invention may be selected from the group comprising L-lactide, D-lactide, meso-lactide and mixtures thereof.

[0150] A PLGA1 as defined herein is used as starting material for making branched PLGA as defined herein. Hence, the term PLGA1 refers to PLGA copolymer before applying the branching process.

[0151] In some embodiments, PLGA1 for preparing a branched PLGA according to the invention, may have a weight average molecular weight (Mw) ranging from 1 kg / mol to 500 kg / mol, preferably from 1.5 kg / mol to 500 kg / mol; preferably from 3.0 to 500 kg / mol, preferably from 4.0 to 400 kg / mol, preferably from 5.5 to 300 kg / mol. The weight average molecular weight can be determined as disclosed in the example section.

[0152] In some embodiments, PLGA1 for preparing a branched PLGA according to the invention, may have a number average molecular weight (Mn) ranging from 5.0 kg / mol to 100 kg / mol; preferably from 7.0 to 90 kg / mol, preferably from 9.0 to 80 kg / mol, preferably from 10.0 to 75 kg / mol. The number average molecular weight can be determined as disclosed in the example section.

[0153] In some embodiments PLGA1 for preparing a branched PLGA according to the invention comprises from 15.0 wt% to 99.0 wt% of glycolide based on the total weight of the PLGA1 ; preferably the PLGA1 comprises from 15.0 wt% to 98.0 wt% of glycolide; preferably the PLGA1 comprises from 16.5 wt% to 98.0% of glycolide; preferably the PLGA1 comprises from 17.0 wt% to 94.0 wt% of glycolide; based on the total weight of the PLGA1 .

[0154] In some embodiments PLGA1 for preparing a branched PLGA according to the invention comprises from 1.0 wt% to 90.0 wt% of lactide based on the total weight of the PLGA1 ; preferably the PLGA1 comprises from 3.0 wt% to 89.0 wt% of lactide; preferably the PLGA1 comprises from 5.0 wt% to 13.0% of lactide. In some embodiments PLGA1 for preparing a branched PLGA according to the invention has a melt flow index of from 0.5 to 200.0 g / 10 min as determined according to ISO1133 at 210 °C and under a load of 2.16 kg; preferably a melt flow index of from 1.0 to 180.0 g / 10 min; preferably a melt flow index of from 1.5 to 150.0 g / 10 min; preferably a melt flow index of from 2.0 to 120.0 g / 10 min; preferably a melt flow index of from 2.5 to 100.0 g / 10 min; preferably a melt flow index of from 2.0 to 80.0 g / 10min, preferably melt flow index of from 3.0 to 80.0 g / 10 min; preferably a melt flow index of from 3.5 to 75.0 g / 10 min.

[0155] In some embodiments PLGA1 for preparing a branched PLGA according to the invention has a melt flow index of from 0.5 to 200.0 g / 10 min as determined according to ISO1133 at 230 °C and under a load of 2.16 kg; preferably a melt flow index of from 1.0 to 180.0 g / 10 min; preferably a melt flow index of from 1.5 to 150.0 g / 10 min; preferably a melt flow index of from 2.0 to 120.0 g / 10 min; preferably a melt flow index of from 2.5 to 100.0 g / 10 min; preferably a melt flow index of from 2.0 to 80.0 g / 10 min; preferably a melt flow index of from 3.0 to 80.0 g / 10 min; preferably a melt flow index of from 3.5 to 75.0 g / 10 min.

[0156] Branching agent

[0157] The term “branching agent” as used herein refers to a chemical compound that has at least one reactive functionality that can attach side chains into a polymer backbone. The reactive functionalities of these branching agents can be a hydroxide, epoxide, isocyanate, oxazoline, oxazine, tris phosphite or peroxide; preferably the functionalities of the branching agents are epoxide and peroxide.

[0158] In some embodiments the branching agent is an epoxy functional compound. As used herein a “epoxy functional compound” is a compound which structure comprises at least one epoxy ( ) functionality. Suitable epoxy functional compounds include epoxidized fats or oils and epoxy functional styrene-acrylate copolymers. In some embodiments, the epoxy functional compound is an epoxy functional styrene-acrylate copolymer.

[0159] In certain embodiments, preferred epoxy-functional styrene-acrylate polymers, such as those for instance Joncryl® brand oligomers, commercially available from BASF. Various grades available and useful are ADR-4400 and ADR-4468, which have the following formula: JoncrylOADR 4400, has the following characteristics: molecular weight 7100 g / mol, glass transition temperature Tg = 65°C, an epoxy group equivalent 485 g / mol. JoncrylOADR 4468, has the following characteristics: molecular weight 7250 g / mol, glass transition temperature Tg = 59°C, an epoxy group equivalent 310 g / mol.

[0160] JoncrylOADR 4400 is commercially available as a masterbatch comprising 25wt% Joncryl® ADR4400 by weight of the masterbatch. Joncryl® ADR4468 is commercially available as a masterbatch comprising 30wt% Joncryl® ADR4400 by weight of the masterbatch.

[0161] In the present invention, the epoxy-functional styrene-acrylate polymers branching agents may be used neat (i.e. added directly) or as a masterbatch.

[0162] In some embodiments the branching agent is an epoxide functional styrene-acrylate copolymer masterbatch. As user herein “epoxide functional styrene-acrylate copolymer masterbatch” refers to a blend of epoxide functional styrene-acrylate copolymer with polylactic acid (PLA).

[0163] In some embodiments the branching agent is a peroxide functional compound; more preferably a cyclic peroxide or a linear peroxide. As used herein a “peroxide functional compound” is a compound which structure comprises at least one peroxide (-O-O-) functionality.

[0164] Suitable cyclic peroxides include the compounds of formulae I, II and II: wherein, wherein Ri, R2, R3, R4, Rs, Rs, are independently selected from the group consisting of hydrogen, Ci-2oalkyl, C3-2ocycloalkyl, Ce-2oaryl, and aryCi-2oalkyl; and wherein each of R1, R2, R3, R4, Rs, Rs may optionally be substituted with one or more groups selected from hydroxy, alkoxy, linear or branched alkyl, aryloxy, alkyloxycarbonyl, carboxy, nitro, and aminocarbonyl.

[0165] In an example, the cyclic peroxide compound is Trigonox 301 , also known as 3,6,9-triethyl- 3,6,9-trimethyl-1 ,4,7-triperoxonane, with CAS number 24748-23-0 and is represented by the following formula:

[0166] In another example, the suitable linear peroxide compounds are Luperox TBEC E, also known as tert-butylperoxy 2-ethylhexyl carbonate, with CAS number 34443-12-4 and is represented by the following formula

[0167] Preparation of the branched PLGA

[0168] The present invention also encompasses a process for the production of a branched PLGA copolymer. Said process comprises the steps of: a. contacting at least one PLGA1 , preferably as defined herein, with at least one branching agent, preferably as defined herein; b. thereby forming said branched PLGA.

[0169] In some embodiments said branched PLGA copolymer is a branched PLGA as defined herein.

[0170] More specifically, in certain embodiments, a process is provided for producing a branched poly(lactide-co-glycolide) (PLGA) polymer as defined herein, and comprising a weight average molecular weight Mw of at least 15 kg / mol and a Mz / Mn of at least 3.3, wherein said process comprising the step of melt blending in an extruder a precursor composition comprising at least one poly(lactide-co-glycolide) (PLGA1) as defined herein with at least one branching agent, preferably as defined herein, thereby obtaining said branched PLGA polymer.

[0171] Term “precursor composition” as used herein intends to refer to a starting composition comprising suitable amounts of PLGA1 (as defined herein). This starting composition is meld blended with a suitable amount of branching agent (as defined herein) under conditions yielding a branched PLGA having the herein defined properties.

[0172] The term “melt-blending” is well known in the art and intends to refer to the process of combining materials at elevated temperatures where at least one component is in a molten or softened state, enabling intimate mixing through heat and shear, e.g. by using an extruder. Unlike physical mixing, which occurs in the solid state without melting, melt blending promotes molecular-level dispersion and interaction between components. The precursor composition - which is melt blended with the branching agent - comprises at least one poly(lactide-co-glycolide) (PLGA1 ) having a melt flow index of from 0.1 to 200.0 g / 10 min as determined according to ISO1133 at 210 °C and under a load of 2.16 kg, or having a melt flow index of from 0.1 to 200.0 g / 10 min as determined according to ISO1133 at 230 °C and under a load of 2.16 kg, and comprising from 15.0 wt% to 99.0 wt% of glycolide based on the total weight of the PLGA1 , wherein the Mw, Mz, and Mn are determined according to the methodology described in the example section.

[0173] In some preferred embodiments, said precursor composition comprises at least 90.0 wt% of poly(lactide-co-glycolide) (PLGA1), such as at least 95.0 wt%, at least 97.0 wt%, at least 99.0 wt%, of PLGA1 , with wt% based on the total weight of the precursor composition. In some preferred embodiments, said precursor composition consists of said poly(lactide-co- glycolide) (PLGA1).

[0174] In some embodiments, the precursor composition comprises less than 10.0 wt% polyglycolide (PGA), or less than 8.0 wt%, or less than 6.5 wt%, or less than 5.0 wt% PGA, or less than 1 .0 wt% PGA, based on the total weight of the precursor composition. In certain embodiments, melt blending step is performed in the absence of polyglycolide (PGA).

[0175] In some embodiments, said contacting step comprises melt blending the at least one PLGA1 with the at least one branching agent. In some embodiments, said contacting step comprises melt blending the at least one PLGA with the at least one branching agent at a temperatures of at least 150 °C; preferably at least 160 °C; preferably at least 170 °C; preferably at least 180 °C; preferably at least 190 °C.

[0176] In a melt blending process, the blend components are mixed together and heated to a range between above their melting points but below their decomposition temperatures. When a PLGA1 as described herein is melt blended in the presence of a branching agent as described herein, a branched PLGA according to the invention may be obtained.

[0177] In some embodiments, said contacting step comprises melt blending the at least one PLGA with the at least one branching agent at a temperatures of at most 260 °C; preferably at most 250 °C; preferably at most 240 °C; preferably at most 230 °C.

[0178] In some embodiments, said contacting step comprises melt blending the at least one PLGA1 with the at least one branching agent at a temperatures of from 150 °C to 260 °C ; preferably from 160 °C to 250 °C; preferably from 170 °C to 240 °C; preferably from 180 °C to 230 °C, preferably from 190°C to 230 °C. The process may be performed in any device that is capable of delivering the required temperature. A Brabender mixer or, a twin-screw extruder, are suitable devices. In some embodiments, the process according to the invention is performed in an extruder.

[0179] In some embodiments, said contacting step comprises melt blending the at least one PLGA with the at least one branching agent in an extruder for at least 30 seconds; preferably for at least 45 seconds; preferably for at least 50 seconds; preferably for at least 60 seconds.

[0180] Compositions

[0181] The present invention also encompasses a composition comprising a branched PLGA as described herein. In some embodiments, said composition is a composition for coating, for instance for coating a substrate. In certain embodiments said composition for coating is therefore herein also denoted as a “coating composition”.

[0182] In some embodiments, the composition (coating composition) comprises branched PLGA in an amount of at most 95.0 wt%, preferably at most 90.0 wt%, preferably at most 85.0 wt%, preferably at most 80.0 wt%, with wt% based on the total weight of the composition.

[0183] In some embodiments, the composition (coating composition) comprises branched PLGA in an amount of between 10.0 and 90.0 wt%, preferably 15.0 and 85.0 wt%, preferably between 20.0 and 75.0 wt%, preferably 15.0 and 75.0 wt%, with wt% based on the total weight of the composition.

[0184] The composition comprising a branched PLGA as described herein may comprise additional components.

[0185] For instance, in some embodiments the composition further comprises at least one polymer. Suitable polymers include but are not limited to for instance: poly(butylene adipate-co- terephthalate) (PBAT), polylactic acid (PLA), polycaprolactone (PCL), polyhydroxyalkanoates (PHAs), poly(butylene succinate) (PBS), poly(butylene succinate-co-adipate) (PBSA), thermoplastic starch (TPS), polyvinyl acetate (PVAc), and mixtures thereof.

[0186] In some embodiments the present composition further comprises from 1.5 to 50.0 wt% of at least one polymer, based on the weight of the composition; preferably 2.0 and 45.0 wt%, preferably between 4.0 and 30.0 wt%, preferably between 2.0 and 20.0 wt% of at least one polymer, with wt% based on the total weight of the composition.

[0187] In some embodiments the composition further comprises at least one plasticizer. In some embodiments the present composition further comprises from 1.5 to 20.0 wt% of at least one plasticizer, based on the weight of the composition; preferably 1.5 and 19.0 wt%, preferably 2.5 and 18.0 wt%, of at least one plasticizer, with wt% based on the total weight of the composition.

[0188] As used herein the term “plasticizer” refers to a substance that is added to a material to make it softer and more flexible, to increase its plasticity, to decrease its viscosity, and / or to decrease friction during its handling in manufacture. Suitable plasticizers include but are not limited to for instance: polyethylene glycol (PEG), epoxidized vegetable oils from soybean oil, linseed oil, castor-oil, sunflower oil, citrate esters, adipates, phthalates, sorbitol, glycerol, fatty acid esters (FAEs) and mixtures thereof.

[0189] In some embodiments the composition further comprises at least one stabilizer. Suitable stabilizers are for instance as inhibitors of oxidative, thermal, hydrolytical or ultraviolet degradation. In some embodiments the present composition further comprises at least one stabilizer in an amount of 0.12 and 2.00 wt%, preferably 0.13 and 1.80 wt%, more preferably between 0.15 and 1.50 wt%, preferably between 0.20 and 1.5 wt%, with wt% based on the total weight of the composition.

[0190] In some embodiments the composition further comprises at least one additive. Suitable additives may be selected from the group comprising: catalyst quenchers, slip and antiblocking agents such as fatty amides; lubricants, extender oils, pH controlling substances such as calcium carbonate, release agents, colorants, reinforcing or non-reinforcing fillers such as silica, clay, chalk, carbon black, and fibrous materials such as glass fibres, natural fibres, wood- derived materials, nucleating agents, accelerators, and combinations thereof.

[0191] In some embodiments the present composition further comprises at least one additive; in some embodiments, said composition further comprises from 100 to 10000 ppm by weight of at least one additional additive; preferably from 200 to 9000 ppm; preferably comprises from 300 to 8000 ppm; preferably from 400 to 7000 ppm; preferably from 500 to 6000 ppm of at least one additional additive, based on the total weight of the composition.

[0192] Uses

[0193] In certain embodiments, the branched PLGA of the invention, and compositions of the invention comprising said branched PLGA are particularly useful for coating a substrate. In some embodiments the coating of a substrate occurs by a process selected from the group comprising extrusion coating, bar and knife coating, lamination coating, suspension coating, emulsion coating and dispersion coating.

[0194] As used herein the term “extrusion coating” refers to a technique that permits the extrusion of a coating layer onto a substrate. As used herein the term “bar coating” refers to a technique wherein solution of the coating is spread across a substrate by a cylindrical bar with wire spiralling around it. The gaps between the wire and the substrate control how much solution is allowed through. This determines the film thickness. As used herein the term “knife coating” refers to a technique wherein an excess of coating material is applied to the substrate and removed by a metering blade to achieve the desired coating thickness. As used herein the term “lamination coating” refers to a technique that involves combining two or more substrates together by 'bonding' them together with a coating. As used herein the term “suspension coating” refers to a technique that involves applying a polymer suspension by, for instance a slot die to a substrate, and then drying the coating. As used herein the term “emulsion coating” refers to a technique that involves applying a polymer emulsion on a substrate. As used herein, the term “dispersion coating” refers to a technique that involves applying a polymer dispersion on a substrate.

[0195] In certain embodiments, the branched PLGA of the invention, and compositions of the invention comprising said branched PLGA are particularly useful for coating a substrate.

[0196] In certain embodiments, the branched PLGA of the invention, and compositions of the invention comprising said branched PLGA are particularly useful for making coated substrates by means of a melt extrusion coating process, due in part to their desirable combination of high melt strength and shear-thinning behaviour. The branched PLGA of the invention exhibits more stable processing due to its reduced neck-in and draw resonance (edge weave). These advantages are especially pronounced at low coating weights. Low coating weights generally require high line speeds, so the ability to achieve these benefits at low coating weight permits higher speed line operation. High line speeds often correlate to high draw-down ratios. The excellent melt strength of the branched PLGA of the invention greatly facilitates coating operations at these high draw-down ratios.

[0197] In some embodiments the present invention also encompasses a substrate coated with branched PLGA according to the invention, or with a composition according to the invention comprising a branched PLGA according to the invention.

[0198] In some embodiments, the substrate is selected from the group comprising, a cellulosic material such as paperboard, paper, cardboard, fibreboard, wood, a wood veneer, or other boardstock; a textile, which may be, for example, made up of woven, knitted, entangled and / or melt-bonded fibres; a polymeric film or sheet, which may be thermoplastic or thermoset material; a metal sheet; a composite material; or any other material that is capable of being processed through the melt extrusion coating apparatus.

[0199] In some embodiments, the branched PLGA or composition comprising branched PLGA of the invention when applied as a coating forms an exposed layer in the final product. In such a case, the branched PLGA or composition comprising branched PLGA coating may impart moisture resistance to the coated substrate by forming a barrier against penetration of water (or other liquid) to the underlying substrate.

[0200] ARTICLES

[0201] The branched PLGA or composition comprising branched PLGA applied as a coating may be used for making articles such as packaging materials, as well as in making disposable food service items such as drink cups. Said articles may be coated on one or both sides with the branched PLGA or composition comprising branched PLGA of the invention.

[0202] The branched PLGA or composition comprising branched PLGA according to the present invention can be used in various applications, such as extruded or blown films, coatings for packaging, in particular for coating paper or board, foamed or moulded articles such as bottles, beakers, or trays, for instance foamed trays for microwavable or ovenable food products, clam shells or other thermoformed articles, or injection-moulded trays.

[0203] Compostability

[0204] The present inventors have surprisingly found that the branched PLGA according to the present invention is compostable; more in particular it is home compostable. This means that articles comprising the branched PLGA according to the present invention, compositions comprising said branched PLGA or substrates coated with the branched PLGA or coated with compositions comprising the branched PLGA of the present invention may also be compostable and more in particular home compostable. It is to be understood that the other components of said article comprising the branched PLGA according to the present invention, compositions comprising said branched PLGA or substrates coated with the branched PLGA or coated with compositions comprising the branched PLGA of the present invention should also be compostable.

[0205] In some embodiments, the article comprising the branched PLGA according to the present invention, or the composition comprising said branched PLGA or the substrates coated with the branched PLGA or the substrate coated with compositions comprising the branched PLGA of the present invention is a biodegradable material.

[0206] The term “biodegradable” as used herein, refers to a material breaking down into substances such as water, carbon and biomass with the help of microorganisms. The process of biodegradation is therefore a natural chemical process and depends on the environmental conditions as well as on the material or application itself. Consequently, the process and its outcome can vary considerably To be labelled a biodegradable material, there is no time limit set on when the product breaks down. The term “compostable” as used herein refers to a material capable of biodegradation at specified conditions (i.e. a certain temperature, timeframe, etc.). At the end of the composting process, for example in an industrial composting plant, only natural products remain (water, carbon, biomass).

[0207] The term “compost” is used to designate a mixture of ingredients used as plant fertilizer and to improve soil's physical, chemical, and biological properties. It is commonly prepared by decomposing plant and food waste, recycling organic materials, and manure. The resulting mixture is rich in plant nutrients and beneficial organisms, such as bacteria, protozoa, nematodes, and fungi. Compost improves soil fertility in gardens, landscaping, horticulture, urban agriculture, and organic farming, reducing dependency on commercial chemical fertilizers.

[0208] In some embodiments, the article comprising the branched PLGA according to the present invention, or the composition comprising said branched PLGA or the substrates coated with the branched PLGA or the substrate coated with compositions comprising the branched PLGA of the present invention is an industrially compostable material or a home compostable material.

[0209] The term “industrially compostable material” refers to a material that is compostable in an industrial composting facility (i.e. at stable temperature conditions). In some embodiments, an industrially compostable material is a material that conforms to EN 13432 and / or ASTM D6400 standards

[0210] The term “home compostable material” refers to a material that is compostable at a lower temperature than the industrially compostable material. The temperature of a home compost is usually less constant as well as being influenced by multiple other factors such as weather conditions. Home composting is a much slower process than industrial composting involving a comparatively smaller volume of waste. In some embodiments a home compostable material is a material that conforms to NF T51-800 (2015) and / or AS 5810 (2010) standards.

[0211] In some embodiments, the article comprising the branched PLGA according to the present invention, or the composition comprising said branched PLGA or the substrates coated with the branched PLGA or the substrate coated with compositions comprising the branched PLGA of the present invention is a recyclable material.

[0212] The term “recyclable material” refers to a material that can be recovered or diverted from the waste stream through available processes and infrastructure and can be collected, processed and returned to use in form of raw materials or goods. The invention will now be illustrated by the following, non-limiting illustrations of particular embodiments of the invention.

[0213] EXAMPLES

[0214] MATERIALS

[0215] The following polymer and other materials were used in the examples. As used in the examples, PLGA1 to PLGA7 all concern starting materials that can be used for making a branched PLGA.

[0216] Polymer “PLGA1” is a PLGA (having 48 wt% glycolide content) having a MFI (210 °C, 2.16kg) of 20 g / 10 min and a glass transition temperature (Tg) of 48 °C.

[0217] Polymer “PLGA2” is a PLGA (having 93 wt% glycolide content) having a MFI (230 °C, 2.16kg) of 72 g / 10 min, melting temperature of 211 °C and a glass transition temperature (Tg) of 42 °C.

[0218] Polymer “PLGA3” is a PLGA (having 23 wt% glycolide content) having a MFI (210 °C, 2.16kg) of 9 g / 10 min, a Mn of 41 kg / mol, a Mw of 94 kg / mol and a Mz of 150 kg / mol.

[0219] Polymer “PLGA4” is a PLGA (having 54 wt% glycolide content) having a MFI (210 °C, 2.16kg) of 7 g / 10 min, a Mn of 39 kg / mol, a Mw of 87 kg / mol and a Mz of 135 kg / mol.

[0220] Polymer “PLGA5” is a PLGA (having 88 wt% glycolide content) having a MFI (210 °C, 2.16kg) of 7 g / 10 min, a Mn of 38 kg / mol, a Mw of 70 kg / mol and a Mz of 113 kg / mol.

[0221] Polymer “PLGA6” is a PLGA (having 18 wt% glycolide content) having a MFI (210°C, 2.16kg) of 20 g / 10 min, a Mn of 42 kg / mol, a Mw of 82 kg / mol and a Mz of 123 kg / mol.

[0222] Polymer “PLGA7” is a PLGA (having 48 wt% glycolide content) having a MFI (210°C, 2.16kg) of 20 g / 10 min, a Mn of 36 kg / mol, a Mw of 69 kg / mol and a Mz of 112 kg / mol.

[0223] The PLGA1 to PLGA7 resins were produced by ring opening polymerization of a mixture of lactide and glycolide in the presence of a suitable catalyst, according to a methods that are known the art. The molecular weight of the PLGA resin is controlled via the addition of a specific amount of initiator according to techniques known in the art.

[0224] The material denoted as “BA1” corresponds to a 25wt% Joncryl® ADR4400 masterbatch (additive), available from Transmare compounding under the name “Bio 6LA-150CE00”.

[0225] The material denoted as “BA2” corresponds to a 30wt% Joncryl® ADR4468 masterbatch (additive), available from Microfol Compounding GmbH & Co KG under the name “Microfol - MB 2305 PLA”. The material denoted as “BA3” corresponds to 3,6,9-Triethyl-3,6,9-trimethyl-1 ,4,7- triperoxonane, CAS No. 24748-23-0, also known as Trigonox® 301 , M=264.3 g / mol, available from Nouryon Functional Chemicals BV.

[0226] The material denoted as “BA4” corresponds to tert-butylperoxy 2-ethylhexl carbonate, CAS No. 34443-12-4, also known as Luperox® TBEC E, M=246.3 g / mol, available from Arkema.

[0227] ANALYSES

[0228] Molecular weight

[0229] The molecular weight parameters of the branched and non-branched PLGAs are: absolute number average molecular weight (Mn), absolute weight average molecular weight (Mw) and absolute z average molecular weight (Mz), and were determined according to the method described below.

[0230] Molecular weight parameter measurements were performed on amorphous PLGA samples (branched and non-branched) which were analysed by size exclusion chromatography (SEC) and in particular by gel permeation chromatography (GPC), using a Viscotek GPC Mx VE2001 system with 1 ,1 ,1 ,3,3,3-Hexafluoro-2-propanol (hexafluoro / sopropanol or HF / P) and 0.02M CF3COOK as solvent at a flow rate of 0.7mL / min. Size exclusion columns were two PSS PFG analytical linear columns (M, 300 x 8.00 mm, 7 pm) in series.20-25 mg of sample was weighed in a 20 ml crimp cap vials and 17 gram HFiP, was added. The suspension was shaken for at least 16 hours at room temperature. After 16 hours 1 ml of the sample was filtered through a PVDF 0.45pm filter, transferred to a 2 ml vial and injected.

[0231] Semi crystalline PLGA samples do not dissolve and therefore first need to be molten and quenched to ensure the amorphous state.

[0232] The molecular weight averages used in establishing molecular weight / property relationships are the number average (Mn), weight average (Mw) and z average (Mz) molecular weight. These averages are defined by the following expressions and are determined form the calculated Mi: Here Nj and Wj are the number and weight, respectively, of molecules having molecular weight Mj. The third representation in each case (farthest right) defines how one obtains these averages from SEC chromatograms, hi is the height (from baseline) of the SEC curve at the ithelution fraction and Mj is the molecular weight of species eluting at this increment.

[0233] Yellowness index

[0234] The Yellowness Index may be directly measured on the polymer pellets, according to ASTM D 1925, using a Konica Minolta CR-410 Chromameter.

[0235] Glycolide content

[0236] In a typical procedure, 0.5 g of PLGA is first completely hydrolysed with methanolic potassium hydroxide. Typically this reaction is completed in 30 minutes at 65°C. In a next step the obtained (hydroxy) acid(s) are (trans) esterificated to its corresponding methyl ester in presence of Amberlyst® 15 ion exchange resin. Typically this reaction is completed in 2 hours at 90°C.

[0237] After this sample derivatization, the solution can be decanted with a syringe and injected into a GC apparatus. Such apparatus may be a Thermo-GC Trace 1300 with e.g. an Agilent® CP- Chirasil Dex CB , L=25m, i.d.=0.25mm, df=0.25 pm GC column, hydrogen carrier gas and FID detector. A gradient oven temperature is generally used (65-170°C) and an injection temperature of 230°C is generally applied. Hexanoic acid may be used as internal standard.

[0238] The resulting chromatograms are analysed with Chromeleon 7.4 software

[0239] MFI

[0240] The melt flow index (MFI) was determined according to ISO1133. The MFI of the non-branched PLGA was determined at a temperature of 210 °C or 230 °C and under a load of 2.16 kg. The MFI of the branched PLGA was determined at a temperature of 210 °C and under a load of 2.16 kg.

[0241] Melt Strength

[0242] Melt strength properties of the (branched) PLGA polymers were tested using a haul-off system. The haul-off system measures the extensional properties of polymer melts by drawing a vertical melt strand of the polymer at a linear accelerating velocity (haul-off speed). The haul- off system measures the force needed to elongate the strand, and calculates elongation stress, draw ratio and apparent elongation rate and viscosity.

[0243] Equipment: Goettfert G25 Rheometer + haul-off unit

[0244] Piston Speed 10 mm / min Haul-off speed range 0-1200 mm / s

[0245] Test time / step 1s

[0246] Temperature 210 °C

[0247] Die 2 / 30 mm (diameter I length).

[0248] Grammage of a substrate (basis weight)

[0249] Grammage is the area density of a product, i.e. the mass per unit of area. It is expressed in g / m2, regardless of its thickness. The grammage of a substrate can be determined in accordance with ISO 536:2012.

[0250] Thickness of a substrate

[0251] The thickness of a substrate, generally expressed in pm, can be determined in accordance with ISO 534:2011.

[0252] Adhesion test

[0253] The adhesion strength of a PLGA or branched PLGA on a coated substrate was evaluated on a scale of 0 to 5, with 5 being the best, using the below scores:

[0254] The following protocol was applied.

[0255] Samples of a coated substrate were cut out, and subjected to tear, and visually inspected by a tester. Per coated substrate, five samples were taken at different positions of the coated substrate. The samples were circular with a diameter of about 110 mm. A cross with a cutter was made in the middle of the circular sample at the side of the coating. A tester then subjected the sample to tear in order to separate the coating from the substrate by pulling from the middle of the cross. The amount of fibres that remain adhered to the coating after separation of the coating from the substrate were evaluated. The percentage of the fibres indicated in the above scoring table thus represents the number of fibres (of the substrate) remaining in the coating layer after separation of the coating layer from the substrate. All samples are cut and evaluated by the same tester in a same way. Five samples were evaluated for each coating composition obtained under the same process conditions. The resulting score is an average of these 5 measurements. This evaluation permits to evaluate the strength of the adhesion of the coating composition to the substrate. The higher the number of fibres, the better the adhesion strength.

[0256] Coating weight

[0257] The coating weight of a coated substrate refers to the amount of branched or unbranched PLGA applied on a substrate. The amount of branched or unbranched PLGA is expressed as weight per given area, in particular in g / m2.

[0258] In the present examples, the coating weight reported for coated substrates is the average of measurements performed on 5 samples of coated substrates. Per coated substrate, five samples were taken at different positions of the coated substrate while avoiding the edges of the coated substrate, where the coating may be less well distributed. Samples of a coated substrate were cut out in a same way as done in the adhesion test: the samples were circular with a diameter of about 110 mm. The samples were weighted on a precision scale. The weight of the substrate without coating composition was also determined and used as the reference value. Each weighing was performed by the same tester, using the same scale. To determine the coating weight, the reference value was subtracted from the total weight of the sample of the coated substrate sample. The coating weight corresponds to an average of the 5 sample measurements.

[0259] Neck-in

[0260] “Neck-in” (synonymous herein for “necking”) can be determined by considering the width of the substrate and the coating width obtained when coating the substrate. Neck-in was measured manually. Measurements were always done by the same person. For each coated substrate tested, a sample of about 10 meters was taken, and neck-in was measured at five different points along these 10 meters. An average of these five measurement points was determined, and neck-in was then calculated as the difference between the substrate width (In the below examples, substrate width used for the tests was 550 mm for all samples) and the average of the five coating width measuring points.

[0261] EXAMPLES

[0262] Example 1 : Branching PLGA with an epoxide-functionalized branching agent.

[0263] BA1 and BA2 were compounded into the PLGA polymer as listed in Table 1 . The compounding of these branching agents into PLGA polymers was performed on a Brabender DSE25x48D twin screw extruder. 1 or 2% of BA1 , or 0.8 or 1 .7% of BA2 were dry blended with the PLGA polymer and fed to the extruder. Prior to using, PLGA2, BA1 and BA2 were pre-dried in a desiccant hot air drier for at least 6 hours at 85°C.

[0264] Tables 1 and 2 show the amounts of each branching agent used, processing conditions and analytical results of the obtained branched polymers. Table 1

[0265] Table 2

[0266] Tables 3 and 4 show the yellowness index and melt flow index of the obtained branched polymers.

[0267] Table 3

[0268] Table 4

[0269] It can be observed from the results on Tables 3 and 4 that the MFI decreases with the addition of branching agent, which means that the viscosity of the branched polymer has increased at the conditions used for the MFI measurement. Example 2: Branching PLGA with peroxides.

[0270] An amount of 1 or 2% of the branching agent BA3 was compounded with the polymers listed in Table 5. The compounding was performed on a Brabender DSE25x48D twin screw extruder. 1 or 2% of BA3 was dry blended with the polymer, mixed and fed to the extruder.

[0271] Prior to use, PLGA5 was pre-dried in a desiccant hot air drier for at least 6 hours at 85°C. PLGA3 and PLGA4 were pre-dried overnight at 40°C in a desiccant hot air drier.

[0272] Table 5 shows the amounts of each branching agent used, processing conditions and analytical results of the obtained branched polymers.

[0273] Table 5

[0274] The results on Table 5 show that the addition of branching agents increases the Mw, Mz, while the Mnremains constant.

[0275] Table 6 shows the yellowness index and melt flow index of the obtained branched polymers. It can be seen that the addition of BA3 reduces the yellowness of the extruded polymers. The darker the initial colour, the greater colour change is achieved. The L*a*b* values listed in Table 6 confirm the changes in colour. According to the L*a*b* values the yellowness index of PLGA5 increases with the addition of the branching agent, which is related to the intense dark colour of the polymer. Visually the sample has become less brown. Table 6 It is clear from the results on Table 6 that MFI of all resins decreases with the addition of branching agent, which means that the viscosity of the branched polymer has increased at the conditions used for the MFI measurement.

[0276] The melt strength properties of the obtained polymers were tested by haul-off system (see Analyses section). The force needed to elongate the strand of melted polymer was measured and plotted against the haul off speed as shown in Figures 1-3 and Table 7.

[0277] It can be seen from the figures, that for the branched PLGAs, a higher haul-off force is needed to elongate the strand of melted polymer. A higher value of this haul-off force indicates a higher melt strength. The branched PLGAs according to the invention have a high melt strength, which indicates that the branched PLGAs of the invention have better processability compared to un-branched PLGA.

[0278] Table 7 Example 3: Branching of a qlycolide-rich PLGA copolymer.

[0279] A PLGA copolymer with a 88 wt% glycolide content, PLGA5, was compounded with one of BA1 , BA3 or BA4 as described in Examples 1 and 2. Table 8 shows the amounts of each branching agent used, processing conditions and analytical results of the obtained branched polymers. The branching number was calculated as disclosed in Example 1.

[0280] Table 8

[0281] The molecular weight of the polymer in Example E40 could not be measured, as its molecular weight was increased to a level above the limit of the SEC column used, which is 1000 kg / mol. For all other cases, the addition of branching agents increased the Mw, Mz, while the Mnslightly decreases.

[0282] It was observed that colour of the branched PLGAs was improved, therefore the yellowness index and melt flow index of the obtained branched polymers was determined (Table 9).

[0283] Table 9 The melt strength properties of the obtained polymers was also tested (Figures 4-6 and Table 10). Similarly to what was observed in Examples 1 and 2, the branched PLGAs require a higher haul-off force to elongate the polymer strand. A higher value of this haul-off force indicates a higher melt strength, and therefore a better processability compared to un-branched PLGA.

[0284] Table 10

[0285]

[0286] Example 4: Extrusion coating of branched PLGA.

[0287] The present example illustrates extrusion coating experiments carried out on a cellulosic substrate using branched PLGA according to the invention as compared to non-branched PLGA.

[0288] The extrusion coating system used in this example, comprises: a hopper for feeding a PLGA1 and branching agent as defined herein to an extruder; an extruder with screw diameter of 60 mm, L / D ratio of about 30; a die having a width of 700 mm; a pressure roll and a glossy chill roll; a surface treatment unit allowing to apply a flame treatment on the substrate before being coated, comprising a Hill Gmbh, type EF 75-1 burner, (Burner CE62-500), with a heat output of max. 50 kW, and propane gas supply

[0289] In the extrusion coating experiments, cooling under the hopper was fixed at about 30°C.

[0290] The width of the coated substrates in the present experiments was 550 mm. The die width was adjusted in order to have a coating in the 550 mm width of the substrate. The chill roll was operated at 20°C. The air gap (die height) was adjusted to 130 mm during the experiments. Pressing pressure used in the pressure roll during the experiments was set at about 5 bar.

[0291] In the present experiments, the substrate to be coated consisted of cartonboard having a thickness of 275 pm, and a grammage of 195 g / m2, available from Stora Enso (BE) under the tradename Cupforma Nature™. The same substrate was used for coating with the inventive branched PLGA and the comparative PLGA.

[0292] Prior to use, the substrate was subjected to a corona treatment. Corona treatment is a surface modification technique that uses a low temperature corona discharge plasma to impart changes in the properties of a surface. The corona plasma is generated by the application of high voltage to an electrode that has a sharp tip. The plasma forms at the tip. A linear array of electrodes is often used to create a curtain of corona plasma.

[0293] Prior to use, the PLGA polymers were dried for a minimum of 12 hrs at 40 °C in a desiccant hot air dryer. Table 11 shows the amounts of each branching agent used and processing conditions of the extrusion coating system. Table 11 also shows the melt temperature during the extrusion as measured by the extruder system (sensor located inside the extruder), as well as the die pressure used and the extruder screw speed applied in the experiments.

[0294] Table 11

[0295] A monolayer polymer coating was applied to the substrate. The coating process was monitored, while stepwise increasing the speed of the coating line. The coated substrates were analysed in terms of neck-in, coating weight and adhesion of the layer of the tested branched or unbranched PLGA to the substrate, using the methodology as explained in the method section above. The results are reported in table 12.

[0296] Table 12

[0297] The values that are underlined in Table 12, mark the maximum speed of the extrusion coating line at which extrusion coating could be performed in a stable manner, allowing to uniformly extrude the branch or unbranched PLGA on the substrate. In contrast, extrusion coating is defined as unstable, when no uniform application of the branch or unbranched PLGA can be done, for instance, when the coating is oscillating, which may lead to extreme neck-in and / or the presence of holes.

[0298] The optimal extrusion coating process has a minimum of neck-in, runs stable at high speed and shows good adhesion at low coating weights. The results of table 12 illustrate that substrates coated with branched PLGA according to the invention can be obtained at higher stable coating speed lines than substrates coated with a PLGA. In addition, substrates coated with branched PLGA according to the invention have shown desirable properties such as lower neck-in than substrates coated with PLGA, and good adhesion. Substrates coated with branched PLGA according to the invention can be produced at higher coating speeds in a more stable fashion and with lower coating weights than those coated with PLGA.

[0299] Results of the experiments shown in Table 12 show that when using branched PLGAs according to the invention, extrusion coating operational efficacy and stability can be improved, resulting in coated substrates with balanced properties. Particularly, using the inventive compositions results in an extrusion coating process showing good processability, and extrusion coated substrates are obtained showing good adhesion, at an affordable coating weight, and with limited neck-in.

[0300] Example 5: Qualitative disintegration test of coated cellulosic substrate.

[0301] The purpose of this experiment was to evaluate the disintegration of a cellulosic substrate coated with a branched PLGA according to the invention, at ambient temperature in compost. The present test set-up is based with some modifications, on the international standard ISO 20200 Plastics - Determination of the degree of disintegration of plastic materials under simulated composting conditions in a laboratory-scale test (2015).

[0302] The test material used for this experiment was cellulosic substrate coated with a monolayer of branched PLGA as described in Experiment E21. The substrate was extrusion coated following the conditions disclosed in Example 4, using a line speed of 80 m / min, to produce a coated cellulosic substrate of ±0.29 mm in thickness, as measured with a digital micrometer. The test material was placed in slide frames, mixed with compost, placed in composting reactors, and incubated at 28 °C ± 2 °C in the dark for 12, 14, 18 and 180 days. Each experiment was performed in duplicate.

[0303] The compost consisted of a 80 / 20 mixture of < 10 mm mature compost and fresh milled Vegetable, Garden and Fruit waste (VGF), respectively. The compost was regularly stirred and moistened if needed. At the same time the visual appearance of the slide frames with the coated substrate was evaluated.

[0304] The mature Compost was a mixture of mature VGF compost and green compost. The mature VGF compost was derived from the organic fraction of a municipal solid waste (MSW) and was further stabilized and aerated in a pilot-scale composting bin at the laboratory under controlled conditions in order to obtain completely mature compost. The age of the mature VGF compost was 15 weeks.

[0305] The green compost was derived from garden waste, prunings, tree roots and stumps and was stabilized in a full-scale composting plant. The mature VGF compost and the green compost were mixed in a weight ratio of 50% mature VGF compost and 50% green compost.

[0306] After an incubation period of 22 weeks, a re-inoculation of the test reactors with 5 wt% fresh milled VGF waste was performed, in order to renew the microbial population and to supply extra nutrients.

[0307] The disintegration of the coated cellulosic substrate (± 0.29 mm) with a branched PLGA according to the invention proceeded very well during the experiment. After 4 weeks of composting, some holes were noticed in parts of the cellulosic layer of the coated substrate. However, most of the coated substrate in a major part of the slide frames remained intact. Moreover, the colour of the coated substrate became dark brown.

[0308] During the following weeks the presence of the cellulosic layer of the coated substrate gradually reduced. After 12 weeks of composting just a small piece of the coated substrate remained present in the slide frames. However, smaller loose pieces of the coated substrate could be retrieved from the composting reactors.

[0309] After 16 weeks, just a very small piece of coated substrate remained present in a few slide frames, while the majority of the slide frames were already empty.

[0310] After 18 weeks of composting the coated substrate in all slide frames had completely disappeared. Moreover, no loose pieces of coated substrate could be retrieved from the composting reactors. The experiment was stopped at this point. The results of this test demonstrate that a cellulosic substrate coated with a branched PLGA according to the invention completely disintegrates at ambient temperature in compost in less than 180 days.

Claims

Claims1. Process for producing a branched poly(lactide-co-glycolide) (PLGA) polymer having a weight average molecular weight Mw of at least 15 kg / mol and a Mz / Mn of at least 3.3, comprising the step of: melt blending in an extruder a precursor composition comprising at least one poly(lactide-co-glycolide) (PLGA1) having a melt flow index of from 0.1 to 200.0 g / 10 min as determined according to ISO1133 at 210 °C and under a load of 2.16 kg, or having a melt flow index of from 0.1 to 200.0 g / 10 min as determined according to ISO1133 at 230 °C and under a load of 2.16 kg, and comprising from 15.0 wt% to 99.0 wt% of glycolide based on the total weight of the PLGA1 , with at least one branching agent, thereby obtaining said branched PLGA polymer, wherein the Mw, Mz, and Mn are determined according to the methodology described in the example section.

2. The process of claim 1 , wherein said precursor composition comprises at least 90.0 wt% of poly(lactide-co-glycolide) (PLGA1), based on the total weight of the precursor composition, and preferably wherein said precursor composition consists of said poly(lactide-co-glycolide) (PLGA1).

3. The process according to any one of claims 1 to 2, wherein the weight ratio of said at least one PLGA1 and said at least one branching agent during said melt blending step ranges from 99.90:0.10 to 95.00:5.00.

4. The process according to any one of claims 1 to 3, wherein said precursor composition is melt blended with the at least one branching agent at a temperature of at least 190°C.

5. The process according to any one of claims 1 to 4, wherein said precursor composition is melt blended with the at least one branching agent for at least 35 seconds, preferably for at least 50 seconds.

6. The process according to any one of claims 1 to 5, wherein said at least one PLGA1 has a melt flow index of from 2.0 to 80.0 g / 10 min as determined according to ISO1133 at 210 °C and under a load of 2.16 kg.

7. The process according to any one of claims 1 to 6, wherein said at least one PLGA1 has a weight average molecular weight Mw of from 1 kg / mol to 500 kg / mol.

8. The process according to any one of claims 1 to 7, wherein said at least one branching agent is selected from the group consisting of an epoxide-functionalized branching agent, a peroxide-functionalized branching agent, an anhydride-functionalized branching agent,an isocyanate-functionalized branching agent, an oxazoline branching agent, an oxazine branching agent, or a combination thereof.

9. The process according to any one of claims 1 to 8, wherein said branched PLGA polymer has a Mz / Mn of at least 3.7.

10. The process according to any one of claims 1 to 9, wherein said branched PLGA polymer has a Mz / Mw which is more than 1.0, and preferably has a Mz / Mw of from 1.1 to 22.0.11 . The process according to any one of claims 1 to 10, wherein the branched PLGA polymer has a melt flow index of from 1.0 to 300.0 g / 10 min as determined according to ISO1133 at 210 °C under a load of 2.16 kg, such as from 1.0 to 100.0 g / 10 min.

12. A branched PLGA produced by the process according to any one of claims 1 to 11 .

13. A branched poly(lactide-co-glycolide) (PLGA) polymer characterized by having a weight average molecular weight Mw of at least 15 kg / mol and a Mz / Mn of at least 3.3, wherein the Mw, Mz, and Mn are determined according to the methodology described in the example section.

14. The branched PLGA polymer according to claim 13, wherein said branched PLGA polymer has a Mz / Mn of at least 3.7.

15. The branched PLGA according to claim 13 or 14, wherein said branched PLGA has a weight average molecular weight Mw of from 15 kg / mol to 2000 kg / mol.

16. The branched PLGA polymer according to any one of claims 13 to 15, wherein said branched PLGA polymer has a Mz / Mw which is more than 1 .0, and preferably has a Mz / Mw of from 1.1 to 22.0.

17. The branched PLGA polymer according to any one of claims 13 to 16, wherein the branched PLGA polymer has a melt flow index of from 1.0 to 300.0 g / 10 min as determined according to ISO1133 at 210 °C under a load of 2.16 kg, such as from 1.0 to 100.0 g / 10 min.

18. The branched PLGA polymer according to any one of claims 13 to 17, wherein said branched PLGA polymer comprises from 10.0 wt% to 99.0 wt% of glycolide based on the total weight of the branched PLGA polymer.

19. A composition, preferably for coating a substrate, comprising a branched PLGA according to any one of the claims 12 to 18.

20. A substrate coated with a branched PLGA according to any one of claims 12 to 18 or with a composition according to claim 19.

21. The substrate according to claim 20, wherein said substrate is a cellulosic substrate or a lignocellulosic substrate; preferably said lignocellulosic or cellulosic substrate is selected from the group comprising paper, paperboard, wood and fibreboard.

22. The substrate according to claims 20 or 21, wherein the substrate is compostable and / or biodegradable.

23. A process for coating a substrate, preferably a substrate as defined in any one of claims 20 to 22, comprising the step of coating, preferably by means of extrusion coating, of a branched PLGA according to any one of the claims 12 to 18, or of a composition according to claim 18, onto at least one surface of the substrate to form a coated substrate.

24. An article comprising a branched PLGA according to any one of claims 12 to 18, or a composition according to claim 19, or - a substrate according to any one of claims 20 to 22.

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