WO2023172130A1

WO2023172130A1 - Biodegradable filament and method of producing biodegradable filament

Info

Publication number: WO2023172130A1
Application number: PCT/NL2023/050107
Authority: WO
Inventors: Bastiaan Krins; Brigitte Angelique BISSCHOP; Johan Bauke DEINUM; Jeroen VAN DER VLIST
Original assignee: Senbis Group B.V.
Priority date: 2022-03-07
Filing date: 2023-03-06
Publication date: 2023-09-14
Also published as: NL2031172B1

Abstract

The invention relates to a biodegradable filament made of a biodegradable polymer composition and a method of producing such filament. The biodegradable polymer composition according to the invention comprises a first biodegradable polymer, a second biodegradable polymer and a plurality of additives which enhance at least the abrasion resistance of the filament such that the biodegradable filament is competitive to conventional filaments.

Description

Biodegradable filament and method of producing biodegradable filament

The invention relates to a biodegradable filament. The invention also relates to a method of producing such biodegradable filament.

The global demand for biodegradable polymers is large and increasing. Biodegradable polymers have a major advantage over nonbiodegradable polymers in terms of degradation because of their ability to completely break down when exposed to microorganisms, aerobic-, and/or anaerobic processes. Plastic pollution is still found everywhere, which is, as commonly known, highly undesired from environmental point of view. The removal of plastic from the environment is labour and cost intensive, wherefore usage of biodegradable polymers could not only benefit from environmental point of view but also if we look at costs of labour used for the removal of conventional plastics from the environment. Further, it must be taken into account that the removal of all plastic from the environment is a challenge, for example when it comes to microplastics. The use of biodegradable polymers would provide a solution here as the decomposition and degradation of the biodegradable polymers could even stabilize the environment and could for example also increase the longevity of the landfills by decreasing the garbage volume. Reprocessing of biodegradable polymers into for example oligomers via microbial, enzymatic, and/or hydrolytic treatment is also conceivable. A non-limiting example of a product which is difficult to remove from the environment and whereof conventional non-biodegradable products could take hundreds of years to decompose is string trimmer line which is used in mowing applications. One is working on the development of fully biodegradable string trimmer lines, but such development faces several challenges. A commonly known challenge in the production of products made from biodegradable plastics is to provide a product which is equivalent with or could replace conventional polymers. Consumers are typically unlikely to replace their conventional plastics by biodegradable alternatives in case the alternative is inferior.

Hence, there is a desire to develop biodegradable products, such as biodegradable filaments, which are competitive with conventional polymers. The invention provides thereto a biodegradable filament which is at least partially made of a biodegradable polymer composition, said biodegradable polymer composition comprising at least one first biodegradable polymer, at least one second biodegradable polymer, at least one stabilizer, in particular at least one thermal stabilizer and/or at least one chain extender, preferably at least one polymeric chain extender.

The biodegradable filament according to the present invention benefits of being substantially fully biodegradable whilst having material properties which are competitive with conventional, non-biodegradable, filaments. The biodegradable polymer composition comprising at least one first biodegradable polymer and at least one second biodegradable polymer provides a stable base structure for the filament. It was found that it is beneficial to use a composition of at least two biodegradable polymers, preferably at least two different biodegradable polymers, in order to improve the characteristics of the composite such as the processability, the resistance to impact and/or abrasion and/or resilience behaviour. However, solely the use of a composition of at least two biodegradable polymers was found to be not sufficient to produce a biodegradable filament which is fully competitive with conventional filaments. The invention teaches to use both a stabilizer and a (polymeric) chain extender, which is against any conventional polymer improvement theories and techniques and unexpectedly resulted in a filament having extraordinary material properties. Stabilizers are known to typically improve the stability, in particular the thermal stability, of the polymer composition. This is beneficial to keep the polymer stable during for example the spinning process, thereby preventing for example thermal degradation or thermo-oxidative degradation. The use of at least one stabilizer prevents clogging and/or the development of lumps and/or nodes on the filament. Chain extenders are known to react with polymers and to modify polymers, in particular polycondensation polymers. Chain extenders can for example be configured to increases molecular weight and melt strength, to improve hydrolytic stability, processability and/or polycondensation. The chain extender could also function as a compatibilizer.

Whilst one would expect that the combination of a stabilizer and a chain extender in a biodegradable polymer composition would result in both additives hampering or even counteracting another, it was surprisingly found that this combination could lead to further improvements of the final product, in particular the filament. The biodegradable polymer according to the present invention in particular benefits of having an improved impact resistance and an improved resilience and of a relatively good processability in conventional extrusion and/or spinning processes. The biodegradable filament according to the present invention could for some application even fully replace a filaments produced from traditional polymers, such as nylon or polyethylene.

When it is referred to a stabilizer, it could also be referred to a first additive, in particular a first additive configured to adapt the thermal stability of the polymer composition. When it is referred to a chain extender, it could also be referred to a is second additive, in particular a second additive which is configured for (polymeric) chain extension. The chain extender is in particular a polymeric chain extender and/or a chain extender for polycondensates. The chain extenders according to the present invention could also be referred to as compatibilizer and/or as a branching agent. It is also conceivable that at least one first biodegradable polymer and/or at least one second biodegradable polymer is at least partially compostable.

In a preferred embodiment, at least one first biodegradable polymer is a biodegradable polyester. It is also conceivable that at least one second biodegradable polymer is a biodegradable polyester. At least one biodegradable polyester can for example be an aliphatic polyester and/or a semi-aromatic polyester. Hence, it is conceivable that at least one first biodegradable polyester is an aliphatic polyester and/or that at least one first biodegradable polyester is a semi-aromatic polyester. It is also conceivable that at least one second biodegradable polyester is an aliphatic polyester and/or that at least one second biodegradable polyester is a semi-aromatic polyester.

The biodegradable polymer composition may comprises at least one polymer matrix. It is conceivable that at least one first biodegradable polymer forms a polymer matrix. In a preferred embodiment, at least one second biodegradable polymer is an impact modifier. It is also conceivable that at least one second biodegradable polymer is configured to improve durability and/or toughness and/or resilience of the polymer composition. It is also conceivable that the biodegradable polymer composition comprises at least two polymer matrices. In a preferred embodiment, the biodegradable polymer composition comprises in the range of 10 wt% to 90 wt% of a first biodegradable polymer. Preferably, the biodegradable polymer composition comprises in the range of 20 wt% to 80 wt%, more preferably in the range of 30 wt% to 70 wt%, even more preferably in the range of 40 wt% to 60 wt% of a first biodegradable polymer. However it is also conceivable that the biodegradable polymer composition comprises in the range of 35 wt% to 55 wt%, more preferably in the range of 30 wt% to 50 wt% or in the range of 45 wt% to 65 wt%, more preferably in the range of 55 wt% to 60 wt% of a first biodegradable polymer. It is also conceivable that the biodegradable polymer composition comprises in the range of 10 wt% to 90 wt%, in particular in the range of 20 wt% to 80 wt%, more in particular in the range of 30 wt% to 70 wt%, even more preferably in the range of 40 wt% to 60 wt% of a second biodegradable polymer. However it is also conceivable that the biodegradable polymer composition comprises in the range of 10 wt% to 37.5 wt%, more preferably in the range of 12.5 wt% to 17.5 wt% or in the range of 20 wt% to 30 wt% of a second biodegradable polymer. In a preferred embodiment, the biodegradable polymer composition comprises in the range of 60 wt% to 80 wt%, in particular 65 wt% to 75 wt%, of a first biodegradable polymer and/or the biodegradable polymer composition comprises in the range of 20 wt% to 40 wt%, in particular 25 wt% to 35 wt%, of a second biodegradable polymer.

At least one first biodegradable polymer is preferably chosen from the group of: polybutylene adipate terephthalate (PBAT), polycaprolactone (PCL), polylactic acid (PLA), polybutylene succinate terephthalate (PBST), poly butylene succinate (PBS), poly(butylene succinate-co-butylene adipate) (PBSA), polybutylene ethylene adipate succinate (PBEAS), polyhydroxyalkanoate (PHA), polyhydroxyalkanoates (PHAs) such as polyhydroxybutyrate (PHB), poly(3- hydroxybutyrate-co-3-hydroxyvalerate) (PHBV) , poly(3-hydroxybutyrate-co-3- hydroxyhexanoate) (PHBH) and/or poly(3-hydroxybutyrate-co-4-hydroxybutyrate). At least one second biodegradable polymer can also be chosen from the group of: polybutylene adipate terephthalate (PBAT), polycaprolactone (PCL), polylactic acid (PLA), polybutylene succinate terephthalate (PBST), polybutylene succinate (PBS), poly(butylene succinate-co-butylene adipate) (PBSA), polybutylene ethylene adipate succinate (PBEAS), polyhydroxyalkanoate (PHA), polyhydroxyalkanoates (PHAs) such as polyhydroxybutyrate (PHB), poly(3-hydroxybutyrate-co-3- hydroxyvalerate) (PHBV) , poly(3-hydroxybutyrate-co-3-hydroxyhexanoate) (PHBH) and/or poly(3-hydroxybutyrate-co-4-hydroxybutyrate). As indicated above, it is preferred that the first biodegradable polymer at least partially differs from the second biodegradable polymer.

In a beneficial embodiment of the filament according to the present invention, the first biodegradable polymer comprises PBS and the second biodegradable polymer comprises PBAT. It is also possible that the first biodegradable polymer is PBS and the second biodegradable polymer is PBAT. This embodiment is in particular of interest as it was found that the PBAT can function as an impact modifier for the PBS.

In a further possible embodiment, it is conceivable that the biodegradable polymer composition comprises at least one biodegradable copolymer, wherein said copolymer comprises at least one first biodegradable polymer and at least one second biodegradable polymer. It is imaginable that at least part of the first biodegradable polymer and the second biodegradable polymer convert into a copolymer under the influence of the chain extender. However, copolymer formation could possibly also at least partially explained by transesterification. At least one stabilizer as applied in the present invention is preferably a thermal stabilizer. It is beneficial if the biodegradable polymer composition comprises at least 0.1 wt% stabilizer. Yet in a further embodiment, it is conceivable that the biodegradable polymer composition comprises at least 0.2 wt%, preferably at least 0.3 wt% stabilizer, more preferably at least 0.4 wt% stabilizer. However, it is also conceivable that the biodegradable polymer composition comprises at least 0.5 wt% stabilizer or at least 0.6 wt% stabilizer. Optionally, the biodegradable polymer composition could comprise at most 5 wt% stabilizer, preferably at most 1 .5 wt% stabilizer, more preferably at most 1 wt%.

In a beneficial embodiment, at least one stabilizer comprises a phenolic antioxidant. It is preferred that said phenolic antioxidant is a sterically hindered phenolic antioxidant. The sterically hindered embodiment could further improve the desired effects of the stabilizer. A non-limiting example a commercial stabilizer which could be applied would be Irganox 1010. It was experimentally found that already relatively low fractions of stabilizer and relatively low fractions of chain extender could significantly improve the characteristics of the biodegradable filament according to the present invention. This means that fractions of said additives can typically be added to a conventional (extrusion) process, without having to significantly adapt the process. The use of relatively low fractions of additives is also beneficial from economic point of view.

At least one chain extender is preferably a polymeric chain extender, more in particular a chain extender for polycondensates. A non-limiting example of a commercially available chain extender which can be applied is Joncryl, for example but not limited to Joncryl ADR 4468.

The biodegradable polymer composition preferably comprises at least 0.1 wt% chain extender. It is also possible that the biodegradable polymer composition comprises at least 0.2 wt%, in particular at least 0.25 wt%, more in particular at least 0.3 wt% and even more in particular at least 0.4 wt% chain extender. It is preferred to limit the amount of chain extender in order to prevent undesired effects of the additive. It is conceivable that an excess of chain extender will cause too much crosslinking of the polymers and/or an excessive entanglement among the molecular chains. Hence, preferably the biodegradable polymer composition comprises a maximum of 5 wt% chain extender, preferably at most 2.5 wt% chain extender, more preferably at most 1 wt% chain extender, and even more preferably at most 0.8 wt% chain extender. It is also conceivable that the biodegradable polymer composition comprises up to 0.5 wt% chain extender.

In a further preferred embodiment, it is conceivable that the characteristics of the filament are further adapted by the use of fibers. Hence, it is conceivable that the biodegradable polymer composition comprises a fraction of fibers, in particular natural fibers. It is conceivable that at least a fraction of fibers, in particular natural fibers, is dispersed within the polymer composition. The fibers could have a positive effect on the abrasion resistance of the filament. The fibers could also have a reinforcing effect for the filament. The biodegradable polymer may for example comprise in the range of 0.05 wt% to 5 wt% of fibers, in particular natural fibers, and preferably in the range of 0.1 wt% to 2 wt%, more preferably in the range of 0.5 wt% to 1 wt%. It is beneficial if at least part of the fibers, if applied, has an average length in the range of 75 to 300 micron. It is for example conceivable that at least a fraction of the fibers has an average length of at least 75 micron, preferably at least 100 micron. Preferably, at least part of the fibers, if applied, has a length to diameter ratio of 3 or higher. Relatively elongated fibers could further improve the characteristics of the filament. Non-limiting example of possible fibers which could be applied are jute fibers and/or cellulosic fibers such as micro-cellulose fibers. Non-limiting examples of fibers which could be applied for a biodegradable filament according to the present invention are cotton, flax, jute, hemp, kenaf, bamboo, sisal and/or coconut fibers.

The filament is in particular a longitudinal filament. At least part of the filament may define a diameter. The diameter of at least part of the filament according to the present invention can for example be in the range of 0.5 to 5 mm, preferably in the range of 1 to 4 mm. It is also conceivable that the diameter of the filament is in the range of 1 .2 to 3.0 mm, preferably in the range of 1 .5 to 2.7 mm, more preferably in the range of 1 .6 to 1 .9 or 2.2 mm. It can also be said that an average diameter of at least part of the filaments falls within any of said ranges. The filament can be a substantially round filament. However, it is also conceivable that the filament is an oval or substantially flat shaped filament. It is conceivable that at least part of the filament is substantially, round, circular, spiral, square, rectangular, flat, oval, and/or angled in shape.

It is also imaginable that at least part of the filament has an substantially flat shaped configuration. The filament could for example be a tape. It is for example possible that at least part of the thickness of the filament is in the range of 100 to 200 microns and/or that at least part of the width of the filament is in the range of 500 to 1000 microns. It is imaginable that the tape is an irregular tape. It is imaginable that at least part of the tape comprises a protrusion. It is also imaginable that at least part of the tape comprises a substantially S-shaped cross section.

In yet a further possible embodiment, the biodegradable polymer composition comprises at least one third biodegradable polymer. It is for example possible that at least one third biodegradable polymer is chosen from the group of: PBAT, PCL, PLA, PBST, PBS, PBSA, PBEAS, PHA, PHB, PHBV and/or PHBH. More in particular, at least one third biodegradable polymer can be chosen from the group of: polybutylene adipate terephthalate (PBAT), polycaprolactone (PCL), polylactic acid (PLA), polybutylene succinate terephthalate (PBST), poly butylene succinate (PBS), poly(butylene succinate-co-butylene adipate) (PBSA), polybutylene ethylene adipate succinate (PBEAS), polyhydroxyalkanoate (PHA), polyhydroxyalkanoates (PHAs) such as polyhydroxybutyrate (PHB), poly(3-hydroxybutyrate-co-3- hydroxyvalerate) (PHBV) , poly(3-hydroxybutyrate-co-3-hydroxyhexanoate) (PHBH) and/or poly(3-hydroxybutyrate-co-4-hydroxybutyrate). In case a third biodegradable polymer is applied, said third biodegradable polymer preferably at least partially differs from the first and second biodegradable polymer. The biodegradable polymer composition could for example comprise at least 10 wt% of a third biodegradable polymer, in particular at least 20 wt%. It is conceivable that the biodegradable polymer composition comprises up to 40 wt%, preferably up to 30 wt% of a third biodegradable polymer. It is also imaginable that the biodegradable polymer composition comprises in the range of 5 wt% to 40 wt%, in particular in the range of 7.5 wt% to 30 wt%, more in particular in the range of 10 wt% to 20 wt% of at least one third biodegradable polymer. It was experimentally found that the use of a third biodegradable polymer could prevent or inhibit the formation of cracks in the material. The biodegradable polymer composition could also comprises at least one further additive, such as for example a colorant.

It is imaginable that at least one biodegradable polymer is a crystalline polymer and/or a semi-crystalline polymer. Hence, it is conceivable that at least one first biodegradable polymer, at least one second biodegradable polymer and/or at least one third biodegradable polymer, if applied, is a crystalline polymer and/or a semicrystalline polymer. It is also conceivable that at least one biodegradable polymer is an aliphatic polyester. Hence, it is conceivable that at least one first biodegradable polymer, at least one second biodegradable polymer and/or at least one third biodegradable polymer, if applied, is an aliphatic polyester.

In yet another possible alternative, at least part of the filament can be coated. It is for example conceivable that the filament is coated with at least one polymer or resin, for example chosen from the group of: PBAT, PCL, PLA, PBST, PBS, PBSA, PBEAS, PHA, PHB, PHBV and/or PHBH. It is also conceivable that at least one filament is a wax coated filament. In case a wax is applied, this is preferably a natural wax.

It is further possible that at least one biodegradable filament comprises at least one transesterification catalyst. The at least one transesterification catalyst could positively contribute to the stability of the filament. It is also imaginable that at least one transesterification catalyst functions as a compatibilizer.

The biodegradable filament according to the present invention is typically obtained via an extrusion process. The biodegradable filament is preferably an extruded filament. It is in particular beneficial if the filament is made using a twin screw extruder. Alternatively a compound could be made using a twin screw extruder process, and subsequently the filament could be made in a process with a single screw extruder. The biodegradable filament according to the present invention is in particular a monofilament. Alternatively, the biodegradable polymer composition according to the present invention could also be applied in a biodegradable multifilament.

The invention also relates to the use of a biodegradable filament according the present invention. The relates in particular to the use of a biodegradable filament according the present invention for use as a string trimmer line, as artificial turf or artificial grass, (tooth)brush filament and/or as packaging material. Hence, the invention for example also relates to an artificial grass fiber. The filament according to the invention could also be referred to as fiber, for example and artificial grass fiber. It is imaginable that at least part of the filament has an substantially flat shaped configuration. The filament could for example also be a tape.

The invention also relates to a product comprising at least one or multiple biodegradable filament(s) according to the present invention. Non-limiting examples of products are string trimmer line, artificial turf or artificial grass, (tooth)brush filament and/or packaging material.

The invention further relates to a method of producing a biodegradable filament, in particular according to the present invention, comprising the steps of: a) providing: o at least one first biodegradable polymer; o at least one second biodegradable polymer; o at least one stabilizer; and o at least one chain extender; b) feeding a mixture of at least one first biodegradable polymer, at least one second biodegradable polymer, at least stabilizer and at least one chain extender to an extruder; and c) extruding the mixture such that a biodegradable filament is formed.

The method according to the present invention enables the production of a substantially fully biodegradable filament. The produced filament benefits of the characteristics as described for the biodegradable filament according to the present invention. Any of the compositions, fractions and/or materials as described for the filament according to the invention also apply to the method according to the invention. The extrusion step is preferably performed by a twin screw extruder.

The invention will be further elucidated based on the following non-limitative clauses.

1 . Biodegradable filament at least partially made of a biodegradable polymer composition, said biodegradable polymer composition comprising:

- at least one first biodegradable polymer;

- at least one second biodegradable polymer;

- at least one stabilizer; and

- at least one chain extender.

2. Biodegradable filament according to clause 1 , wherein at least one first biodegradable polymer is a biodegradable polyester and/or wherein at least one second biodegradable polymer is a biodegradable polyester.

3. Biodegradable filament according to clause 2, wherein at least one biodegradable polyester is an aliphatic polyester and/or wherein at least one biodegradable polyester is a semi-aromatic polyester. 4. Biodegradable filament according to any of the previous clauses, wherein the biodegradable polymer composition comprises in the range of 10 wt% to 90 wt%, in particular in the range of 20 wt% to 80 wt%, more in particular in the range of 30 wt% to 70 wt%, of a first biodegradable polymer.

5. Biodegradable filament according to any of the previous clauses, wherein the biodegradable polymer composition comprises in the range of 10 wt% to 90 wt%, in particular in the range of 20 wt% to 80 wt%, more in particular in the range of 30 wt% to 70 wt%, of a second biodegradable polymer.

6. Biodegradable filament according to any of the previous clauses, wherein at least one first biodegradable polymer is chosen from the group of: PBAT, PBST, PBS, PBSA, PBEAS, PHB, PHBV and/or PHBH.

7. Biodegradable filament according to any of the previous clauses, wherein at least one second biodegradable polymer is chosen from the group of: PBAT, PBST, PBS, PBSA, PBEAS, PHB, PHBV and/or PHBH.

8. Biodegradable filament according to any of the previous clauses, wherein the first biodegradable polymer is PBS and wherein the second biodegradable polymer is PBAT.

9. Biodegradable filament according to any of the previous clauses, wherein the biodegradable polymer composition comprises at least one biodegradable copolymer, wherein said copolymer comprises at least one first biodegradable polymer and at least one second biodegradable polymer.

10. Biodegradable filament according to any of the previous clauses, wherein at least one stabilizer is thermal stabilizer.

11 . Biodegradable filament according to any of the previous clauses, comprising at least 0.1 wt%, preferably at least 0.2 wt%, more preferably at least 0.3 wt% stabilizer. 12. Biodegradable filament according to any of the previous clauses, wherein at least one stabilizer comprises a phenolic antioxidant, preferably a sterically hindered phenolic antioxidant.

13. Biodegradable filament according to any of the previous clauses, wherein at least one chain extender is a polymeric chain extender.

14. Biodegradable filament according to any of the previous clauses, comprising at least 0.1 wt%, preferably at least 0.2 wt%, more preferably at least 0.3 wt% chain extender.

15. Biodegradable filament according to any of the previous clauses, wherein the biodegradable polymer composition comprising a fraction of fibers, in particular natural fibers.

16. Biodegradable filament according to clause 15, wherein at least part of the fibers has an average length in the range of 75 to 300 micron.

17. Biodegradable filament according to clause 15 or 16, wherein at least part of fibers has a length to diameter ratio of 3 or higher.

18. Biodegradable filament according to any of clauses 15 to 17, wherein at least part of the fibers are jute fibers and/or micro-cellulose fibers.

19. Biodegradable filament according to any of the previous clauses, wherein the biodegradable polymer composition comprises at least one third biodegradable polymer.

20. Biodegradable filament according to clause 19, wherein at least one third biodegradable polymer is chosen from the group of: PBAT, PBST, PBS, PBSA, PBEAS, PHB, PHBV and/or PHBH.

21 . Biodegradable filament according to any of the previous clauses, wherein the biodegradable filament is obtained via an extrusion process. 22. Biodegradable filament according to any of the previous clauses, wherein the filament is a monofilament.

23. Use of a biodegradable filament according to any of the previous clauses.

24. Method of producing a biodegradable filament, in particular according to any of clauses 1 to 22, comprising the steps of: d) providing: o at least one first biodegradable polymer; o at least one second biodegradable polymer; o at least one stabilizer; and o at least one chain extender; e) feeding a mixture of at least one first biodegradable polymer, at least one second biodegradable polymer, at least stabilizer and at least one chain extender to an extruder; and f) extruding the mixture such that a biodegradable filament is formed.

25. Method according to clause 24, wherein the extrusion step is performed by a twin screw extruder.

It will be clear that the invention is not limited to the exemplary embodiments which are described here, but that countless variants are possible within the framework of the attached claims, which will be obvious to the person skilled in the art. In this case, it is conceivable for different inventive concepts and/or technical measures of the above-described variant embodiments to be completely or partly combined without departing from the inventive idea described in the attached claims.

The verb 'comprise' and its conjugations as used in this patent document are understood to mean not only 'comprise', but to also include the expressions 'contain', 'substantially contain', 'formed by' and conjugations thereof.

Claims

1 . Biodegradable filament made of a biodegradable polymer composition, said biodegradable polymer composition comprising:

- at least one first biodegradable polymer;

- at least one second biodegradable polymer; and

- at least one chain extender.

2. Biodegradable filament according to claim 1 , wherein at least one first biodegradable polymer is a biodegradable polyester and/or wherein at least one second biodegradable polymer is a biodegradable polyester.

3. Biodegradable filament according to claim 2, wherein at least one biodegradable polyester is an aliphatic polyester and/or wherein at least one biodegradable polyester is a semi-aromatic polyester.

4. Biodegradable filament according to any of the previous claims, wherein the biodegradable polymer composition comprises in the range of 10 wt% to 90 wt%, in particular in the range of 20 wt% to 80 wt%, more in particular in the range of 30 wt% to 70 wt%, of a first biodegradable polymer.

5. Biodegradable filament according to any of the previous claims, wherein the biodegradable polymer composition comprises in the range of 10 wt% to 90 wt%, in particular in the range of 20 wt% to 80 wt%, more in particular in the range of 30 wt% to 70 wt%, of a second biodegradable polymer.

6. Biodegradable filament according to any of the previous claims, wherein at least one first biodegradable polymer is chosen from the group of: PBAT, PCL, PLA, PBST, PBS, PBSA, PBEAS, PHA, PHB, PHBV and/or PHBH.

7. Biodegradable filament according to any of the previous claims, wherein at least one second biodegradable polymer is chosen from the group of: PBAT, PCL, PLA, PBST, PBS, PBSA, PBEAS, PHA, PHB, PHBV and/or PHBH.

8. Biodegradable filament according to any of the previous claims, wherein the first biodegradable polymer is PBS and wherein the second biodegradable polymer is PBAT.

9. Biodegradable filament according to any of the previous claims, wherein the biodegradable polymer composition comprises at least one biodegradable copolymer, wherein said copolymer comprises at least one first biodegradable polymer and at least one second biodegradable polymer.

10. Biodegradable filament according to any of the previous claims, comprising at least one stabilizer, in particular wherein at least one stabilizer is thermal stabilizer.

11 . Biodegradable filament according to claim 10, comprising at least 0.1 wt%, preferably at least 0.2 wt%, more preferably at least 0.3 wt% stabilizer.

12. Biodegradable filament according to claim 10 or 11 , wherein at least one stabilizer comprises a phenolic antioxidant, preferably a sterically hindered phenolic antioxidant.

13. Biodegradable filament according to any of the previous claims, wherein at least one chain extender is a polymeric chain extender.

14. Biodegradable filament according to any of the previous claims, comprising at least 0.1 wt%, preferably at least 0.2 wt%, more preferably at least 0.3 wt% chain extender.

15. Biodegradable filament according to any of the previous claims, wherein the biodegradable polymer composition comprising a fraction of fibers, in particular natural fibers.

16. Biodegradable filament according to claim 15, wherein at least part of the fibers has an average length in the range of 75 to 300 micron.

17. Biodegradable filament according to claim 15 or 16, wherein at least part of fibers has a length to diameter ratio of 3 or higher.

18. Biodegradable filament according to any of claims 15 to 17, wherein at least part of the fibers are jute fibers and/or micro-cellulose fibers.

19. Biodegradable filament according to any of the previous claims, wherein the biodegradable polymer composition comprises at least one third biodegradable polymer.

20. Biodegradable filament according to claim 19, wherein at least one third biodegradable polymer is chosen from the group of: PBAT, PCL, PLA, PBST, PBS, PBSA, PBEAS, PHA, PHB, PHBV and/or PHBH.

21 . Biodegradable filament according to claim 19 or 20, wherein the biodegradable polymer composition comprises in the range of 5 wt% to 40 wt%, in particular in the range of 7.5 wt% to 30 wt%, more in particular in the range of 10 wt% to 20 wt% of at least one third biodegradable polymer.

22. Biodegradable filament according to any of the previous claims, comprising at least one transesterification catalyst.

23. Biodegradable filament according to any of the previous claims, wherein the biodegradable filament is obtained via an extrusion process.

24. Biodegradable filament according to any of the previous claims, wherein the filament is a monofilament.

25. Use of a biodegradable filament according to any of the previous claims.

26. Method of producing a biodegradable filament, in particular according to any of claims 1 to 24, comprising the steps of: a) providing: o at least one first biodegradable polymer; o at least one second biodegradable polymer; and o at least one chain extender; b) feeding a mixture of at least one first biodegradable polymer, at least one second biodegradable polymer and at least one chain extender to an extruder; and c) extruding the mixture such that a biodegradable filament is formed.

27. Method according to claim 26, wherein the extrusion step is performed by a twin screw extruder.