Non-metallic and compostable twist-tie based on PLA compositions

Abstract

Non-metallic and compostable twist-tie based on PLA compositions The present invention refers to a non-metallic and compostable twist-tie based on a composition comprising a poly(L-lactide) homopolymer and at least one biodegradable copolymer; and its preparation process.

Description

[0001] Non-metallic and compostable twist-tie based on PLA compositions

[0002] This application claims the benefit of European Patent Application EP24382357.2 filed April 8, 2024.

[0003] The present invention belongs to the field of non-metallic and compostable twist-ties, and more particularly twist-ties made of PLA compositions.

[0004] Background Art

[0005] Twist ties are made of one or more metal wires encased in a thin strip of paper or plastic. The wire core allows that it can bend and retain its shape. Though twist ties were originally designed to secure the openings of garbage bags, bread bags, and the like, they now find use in a vast number of applications.

[0006] The name "twist tie” derives from the method by which these fasteners work: a twist tie is wrapped around an item or items, and its ends twisted together to secure the hold. Polymeric materials and composites are not typically conformable, i.e. they do not hold their shape after they have been deformed. Metal core twist-ties suffer from obvious known disadvantages.

[0007] A variety of non-metallic ties, such as polymeric ties have been developed. There have been numerous attempts to develop a biodegradable and compostable polymeric twist tie that exhibits good processability and desirable toughness and flexibility characteristics while also being easily fastenable and unfastenable over numerous cycles.

[0008] There exists a need for rigid, but conformable and compostable polymeric twist tie that is metal-free and characterized by additional appropriate physico-chemical and mechanical properties.

[0009] Summary of Invention

[0010] The inventors of the present invention have surprisingly provided a non-metallic and compostable twist tie prepared from a polymeric biodegradable materials wherein the body of the twist tie is essentially free of metallic materials, e.g., it does not contain wires or other metallic structures.

[0011] Thus, the non-metallic and compostable twist-tie of the present invention is prepared from a compostable composition comprising:

[0012] (I) a poly (L-lactide) homopolymer;

[0013] (II) at least one biodegradable copolymer;

[0014] (ill) optionally at least one biodegradable homo- or copolymer other than (I) or (II);

[0015] (iv) optionally at least one additive. In the context of the present invention, the term "compostable” means that the material (i.e. composition, homopolymer, copolymer) is degraded by the action of organisms producing CO2, H2O, inorganic compounds and biomass in a controlled period of time and under certain conditions.

[0016] In the context of the present invention, the term "biodegradable " means that the material (i.e. composition, homopolymer, copolymer) is degraded by the action of biological agents and other physical agents, under environmental conditions that occur in nature and that transform these substances into nutrients, carbon dioxide, water and biomass.

[0017] By "tie" is meant a generally elongated member typically in the shape of a filament or ribbon that functions as a closure for packaging and the like. The tie in one embodiment operates by twisting of the ends of the member and is thus a "twist-tie". In other embodiments, the tie operates by folding back the ends of the member on itself and is a "tin-tie". Since the ties of the present invention are essentially free of metallic materials, the expression "tin-tie" as used herein means a member that has the shape, general characteristics and function of a tin-tie, but without a contained tin or other metallic member.

[0018] The non-metallic and compostable twist-ties according to the present invention show a high thermal, chemical, and rheological stability, being stable under processing, storage and use conditions. The non- metallic ties according to the present invention are compostable. In a particular embodiment the non-metallic and compostable twist-tie of the present invention are compostable under any of UNE-13432, UNE-EN 14995, ISO 18606, ISO 17088 and ASTM D6400

[0019] The non-metallic and compostable twist-tie according to the present invention is preferably used to seal a package having an opening at an end. To seal the package, package material adjacent to the opening is gathered. The non-metallic and compostable twist-tie is wrapped around the gathered package material until end portions of the polymeric twist tie are adjacent to each other. The end portions are then twisted with relative to the remainder of the polymeric twist to fasten the twist tie onto the package.

[0020] To accomplish the sealing of the package, the non-metallic and compostable twist-tie must exhibit several physical characteristics. In particular, the non-metallic and compostable twist-tie must replicate many of the desirable traits exhibited by wire twist ties, such as retaining a selected position when fastened and being capable of repeated cycles of fastening and unfastening.

[0021] Additionally, the non-metallic and compostable twist-tie according to the present invention is used as a fastener to tie products, e.g. to be placed directly around the products itself (e.g. such as to fastening agricultural products such as to fasten plants to stakes; or to secure bundled electric cable) and other fastening tasks.

[0022] Thus, the first aspect of the invention relates to a non-metallic and compostable twist-tie prepared from a compostable composition comprising: (i) a poly (L-lactide) homopolymer;

[0023] (ii) at least one biodegradable copolymer selected from a polylactide based copolymer, a poly (s- caprolactone) based copolymer, a copolymer of polybutylene adipate-co-terephthalate (PBAT), a copolymer of p-hydroxybutyric acid and p-hydroxyvaleric acid (PHBV), and a copolymer of polybutylene succinate adipate (PBSA);;

[0024] (I) optionally at least one additional biodegradable and compostable homopolymer selected from a homopolymer of poly(s-caprolactone), a homopolymer of polybutylene succinate, a homopolymer of polyhydroxybutyric acid, a homopolymer of polyhydroxyvaleric acid; and

[0025] (ill) optionally at least one additive. wherein the polylactide based copolymer is a polymer prepared from at least two different monomers being one of them selected from L-lactide, D-lactide and LD-lactide, and the second monomer being selected from s-caprolactone, butylene succinate; hydroxybutyric acid, hydroxyvaleric acid; and polybutylene succinate adipate; wherein the poly(s-caprolactone) based copolymer, is a polymer prepared from at least two different monomers being one of them s-caprolactone (PCL), and the second monomer being selected from lactic acid, butylene succinate; hydroxybutyric acid, hydroxyvaleric acid, and polybutylene succinate adipate; and wherein the non-metallic twist-tie exhibits the following properties: a. flexural modulus ranging from 2000-3800 MPa; b. Young modulus ranging from 2000-3800 MPa; c. filament tenacity ranging from 2.5-4.5 gf / den; d. elongation at breakage ranging from 10-80%; and e. tensile strength at breakage ranging from 20-55 MPa.

[0026] A second aspect of the invention relates to a process for the preparation of the non-metallic and compostable twist tie of the first aspect of the invention comprising: (i) preparing a PLA based composition as defined herein; (ii) shaping the composition to form the non-metallic and compostable twist-tie.

[0027] A third aspect of the invention relates to a non-metallic and compostable twist-tie obtainable according to the method as described herein.

[0028] A fourth aspect relates to the use of the non-metallic and compostable twist-tie according to the invention, for sealing packages or for tying, fastening or securing products, particularly for agricultural products or electric cables. Detailed description of the invention

[0029] All terms as used herein in this application, unless otherwise stated, shall be understood in their ordinary meaning as known in the art. Other more specific definition terms as used in the present application are as set forth below and are intended to apply uniformly throughout the specification and claims unless an otherwise expressly set out definition provides a broader definition.

[0030] In the context of the present invention, by non-metallic is meant essentially free, preferably completely free, of metal or metallic compounds.

[0031] Throughout this disclosure, various aspects of the invention can be presented in a range format. It should be understood that the description in range format is merely for convenience and brevity and should not be construed as an inflexible limitation on the scope of the invention, Accordingly, the description of a range should be considered to have specifically disclosed all the possible subranges as well as individual numerical values within that range, including both the lower and the upper endpoints of the range. For example, description of a range such as from 1 to 6 should be considered to have specifically disclosed subranges such as from 1 to 3, from 1 to 4, from 1 to 5, from 2 to 4, from 2 to 6, from 3 to 6 etc., as well as individual numbers within that range, for example, 1, 2, 2.7, 3, 4, 5, 5.3, and 6. This applies regardless of the breadth of the range.

[0032] The term "percentage (%) by weight” refers to the percentage of ingredient in relation to the total weight.

[0033] The term "about" or "around” as used herein refers to a range of values ± 10% of a specified value. For example, the expression "about 0.5" or "around 0.5” includes ± 10% of 0.5, i.e. from 0.45 to 0.55.

[0034] As used herein, the term "repeating unit”, or "block” refers to a repeating monomeric unit. A repeating unit or a block may consist of a single monomer or may be comprised of one or more monomers, randomly or block, resulting in a "mixed block”.

[0035] One skilled in the art will recognize that a monomer repeating unit is defined by square brackets (“[ ]”) depicted around the repeating monomer unit. The number (or letter representing a numerical range) on the lower right of the brackets represents the number of monomer units that are present in the polymer chain.

[0036] In an embodiment of the first aspect of the invention, the non-metallic and compostable twist-tie is prepared from a composition comprising:

[0037] (i) a poly (L-lactide) homopolymer;

[0038] (ii) at least one biodegradable copolymer selected from a polylactide based copolymer, a poly (s- caprolactone) based copolymer, a copolymer of polybutylene adipate-co-terephthalate (PBAT), a copolymer of p-hydroxybutyric acid and p-hydroxyvaleric acid (PHBV), and a copolymer of polybutylene succinate adipate (PBSA); (iii) optionally at least one additional biodegradable and compostable homopolymer selected from a homopolymer of poly(s-caprolactone), a homopolymer of polybutylene succinate, a homopolymer of polyhydroxybutyric acid, a homopolymer of polyhydroxyvaleric acid; and

[0039] (iv) optionally at least one additive; wherein the polylactide based copolymer is a polymer prepared from at least two different monomers being one of them selected from L-lactide, D-lactide and LD-lactide, and the second monomer being selected from s-caprolactone, butylene succinate; hydroxybutyric acid, hydroxyvaleric acid; and polybutylene succinate adipate; wherein the poly(s-caprolactone) based copolymer, is a polymer prepared from at least two different monomers being one of them s-caprolactone (PCL), and the second monomer being selected from lactic acid, butylene succinate; hydroxybutyric acid, hydroxyvaleric acid, and polybutylene succinate adipate.

[0040] In an embodiment, the non-metallic and compostable twist-tie is prepared from a composition comprising:

[0041] (i) a poly (L-lactide) homopolymer;

[0042] (ii) at least one biodegradable polylactide based copolymer;

[0043] (iii) optionally at least one additional biodegradable copolymer selected from a poly(s-caprolactone) based copolymer, a copolymer of polybutylene adipate-co-terephthalate (PBAT), a copolymer of p-hydroxybutyric acid and p-hydroxyvaleric acid (PHBV), and a copolymer of polybutylene succinate adipate (PBSA);

[0044] (iv) optionally at least one biodegradable homopolymer selected from a homopolymer of poly (s- caprolactone), a homopolymer of polybutylene succinate, a homopolymer of polyhydroxybutyric acid, a homopolymer of polyhydroxyvaleric acid; and

[0045] (v) optionally at least one additive; wherein the polylactide based copolymer and the poly(s-caprolactone) based copolymer are as defined above.

[0046] In an embodiment of the first aspect of the invention, the non-metallic and compostable twist-tie is prepared from a composition comprising:

[0047] (I) a poly (L-lactide) homopolymer;

[0048] (II) at least one biodegradable polylactide based copolymer;

[0049] (iii) optionally at least one additional biodegradable copolymer selected from a poly(s-caprolactone) based copolymer, a copolymer of polybutylene adipate-co-terephthalate (PBAT), a copolymer of P-hydroxybutyric acid and p-hydroxyvaleric acid (PHBV), and a copolymer of polybutylene succinate adipate (PBSA); (iv) at least one additional biodegradable homopolymer selected from a homopolymer of poly (s- caprolactone), a homopolymer of polybutylene succinate, a homopolymer of polyhydroxybutyric acid, a homopolymer of polyhydroxyvaleric acid; and

[0050] (v) optionally at least one additive; wherein the polylactide based copolymer and the poly(s-caprolactone) based copolymer are as defined above.

[0051] The term "copolymer” as used herein refers to a polymer derived from more than one monomer. The copolymer may be a random or a block copolymer. The term "random copolymer” as used herein refers to a copolymer in which the monomer units are located randomly in the polymer molecule. The term "block copolymer” as used herein refers to a copolymer that comprises at least two different monomer units that upon polymerization form at least two chemically distinct regions, segments or blocks that are chemically distinguishable from one another.

[0052] In an embodiment, the at least one biodegradable copolymer (II) is a block copolymer wherein the percentage by weight of a first block ranges from 40 % to 90%, preferably from 50 % to 70%; and the percentage by weight of a second block ranged from 10% to 60%, preferably from 30 % to 50%; being the sum equal to 100%.

[0053] In an embodiment, the at least one biodegradable copolymer (II) is a polylactide based copolymer. In an embodiment, the at least one biodegradable copolymer (II) is a block copolymer; preferably, the at least one biodegradable copolymer (II) is a polylactide based block copolymer; wherein the polylactide based copolymer is a polymer prepared from at least two different monomers being one of them L-lactide, D-lactide or LD- lactide, thereby the copolymer thus obtained comprises at least blocks of poly (lactide) (PLA), and the second block comprising repeating units selected from s-caprolactone, butylene succinate; hydroxybutyric acid, hydroxyvaleric acid; and polybutylene succinate adipate. In some embodiments, each of the repeating units of the second block may be the same or different from each other.

[0054] In an embodiment, the non-metallic and compostable twist-tie is prepared from a composition comprising:

[0055] (I) a poly (L-lactide) homopolymer;

[0056] (II) at least one biodegradable poly(L-lactide)-co-polycaprolactone (PLA-b-PCL) block copolymer;

[0057] (ill) optionally at least one additional biodegradable copolymer selected from a poly(s-caprolactone) based copolymer, a copolymer of polybutylene adipate-co-terephthalate (PBAT), a copolymer of p-hydroxybutyric acid and p-hydroxyvaleric acid (PHBV), and a copolymer of polybutylene succinate adipate (PBSA);

[0058] (iv) optionally at least one biodegradable homopolymer selected from a homopolymer of poly (s- caprolactone), a homopolymer of polybutylene succinate, a homopolymer of polyhydroxybutyric acid, a homopolymer of polyhydroxyvaleric acid; and (v) optionally at least one additive; wherein the poly(s-caprolactone) based copolymer is as defined above.

[0059] In one embodiment, the non-metallic and compostable twist-tie is prepared from a composition comprising:

[0060] (i) a poly (L-lactide) homopolymer;

[0061] (ii) at least one biodegradable poly(L-lactide)-co-polycaprolactone (PLA-b-PCL) block copolymer;

[0062] (iii) at least one additional biodegradable copolymer selected from a poly(s-caprolactone) based copolymer, a copolymer of polybutylene adipate-co-terephthalate (PBAT), a copolymer of p- hydroxybutyric acid and p-hydroxyvaleric acid (PHBV), and a copolymer of polybutylene succinate adipate (PBSA);

[0063] (iv) optionally at least one biodegradable homopolymer selected from a homopolymer of poly (s- caprolactone), a homopolymer of polybutylene succinate, a homopolymer of polyhydroxybutyric acid, a homopolymer of polyhydroxyvaleric acid; and

[0064] (v) optionally at least one additive; wherein the poly(s-caprolactone) based copolymer is as defined above.

[0065] In one embodiment, the non-metallic and compostable twist-tie is prepared from a composition comprising:

[0066] (I) a poly (L-lactide) homopolymer;

[0067] (II) at least one biodegradable poly(L-lactide)-co-polycaprolactone (PLA-b-PCL) block copolymer;

[0068] (iii) at least one additional biodegradable copolymer selected from a poly(s-caprolactone) based copolymer, a copolymer of polybutylene adipate-co-terephthalate (PBAT), a copolymer of - hydroxybutyric acid and p-hydroxyvaleric acid (PHBV), and a copolymer of polybutylene succinate adipate (PBSA);

[0069] (iv) at least one biodegradable homopolymer selected from a homopolymer of poly(s-caprolactone), a homopolymer of polybutylene succinate, a homopolymer of polyhydroxybutyric acid, a homopolymer of polyhydroxyvaleric acid; and

[0070] (v) at least one additive; wherein the poly(s-caprolatone) based copolymer is as defined above.

[0071] In some embodiments, the percentage by weight of the poly (L-lactide) homopolymer (I) ranges from 55 wt% to 97 wt%, preferably from 60 wt% to 96 wt%, more preferably from 70 wt% to 95 wt%; the percentage by weight of the at least one biodegradable copolymer (II) ranges from 3 wt% to 20 wt%, preferably from 4 wt% to 18 wt%, more preferably from 5 wt% to 15 wt%; the percentage by weight of the at least one additional biodegradable copolymer (iii) ranges from 0 wt% to 20 wt%, preferably from 2 wt% to 15 wt%, more preferably from 5 wt% to 10 wt%; the percentage by weight of the at least one additional biodegradable homopolymer (iv) ranges from 0 wt% to 20 wt%, preferably from 2 wt% to 15 wt%, more preferably from 5 wt% to 10 wt%; and the percentage by weight of the at least one additive (iv) ranges from 0 wt% to 10 wt%, preferably from 2 wt% to 15 wt%, more preferably from 5 wt% to 10 wt%; being the sum of the percentages equal to 100%.

[0072] In one embodiment, the non-metallic and compostable twist-tie is prepared from a composition wherein the copolymer (II) is a polylactide based block copolymer wherein the percentage by weight of the first block ranges from 40 % to 90%, preferably from 50 % to 70%; and the percentage by weight of the second block ranged from 10% to 60%, preferably from 30 % to 50%; being the sum equal to 100%; being the first block and second block as defined above.

[0073] In one embodiment, the non-metallic and compostable twist-tie is prepared from a composition wherein the poly (L-lactide) homopolymer (I) has a number average molecular weight (Mn) ranging from 20.000 to 500.000 g / mol measured by gel permeation chromatography (GPC); the at least one biodegradable copolymer (II) has a number average molecular weight (Mn) ranging from 30.000 to 300.000 g / mol measured by gel permeation chromatography (GPC); the optional at least one biodegradable copolymer (ill) has a number average molecular weight (Mn) ranging from 50.000 to 300.000 g / mol measured by gel permeation chromatography (GPC); and the optional at least one biodegradable homopolymer (iv) has a number average molecular weight (Mn) ranging from 20.000 to 500.000 g / mol measured by gel permeation chromatography (GPC).

[0074] In an embodiment, the non-metallic and compostable twist-tie is prepared from a composition wherein the block copolymer (II) is one of formula (I): wherein: m is an integer from 50 to 10000, preferably from 100 to 8000, more preferably from 130 to 5000, particularly preferred from 139 to 1.388; n is an integer from 30 to 6000, preferably from 50 to 3000, more preferably from 80 to 1000, particularly preferred from 88 to 876; wherein in the second block defined by square bracket with the numerical value n, X is a repeating unit selected from s-caprolactone, hydroxybutyric acid, hydroxyvaleric acid, butylene succinate and butylene succinate adipate. wherein the first block defined by square bracket with the numerical value m, the polylactide monomer is selected from L-lactide, D-lactide and LD-lactide. wherein In is a radical derived from a proper initiator.

[0075] In an embodiment, the non-metallic and compostable twist-tie is prepared from a composition wherein the block copolymer (II) is one of formula (I) as defined above; and the percentage by weight of the poly (L-lactide) homopolymer (I) ranges from 55 wt% to 97 wt%, preferably from 60 wt% to 96 wt%, more preferably from 70 wt% to 95 wt%; the percentage by weight of the at least one copolymer (II) ranges from 3 wt% to 20 wt%, preferably from 4 wt% to 18 wt%, more preferably from 5 wt% to 15 wt%; the percentage by weight of the at least one additional biodegradable copolymer (ill) ranges from 0 wt% to 20 wt%, preferably from 2 wt% to 15 wt%, more preferably from 5 wt% to 10 wt%; the percentage by weight of the at least one additional biodegradable homopolymer (iv) ranges from 0 wt% to 20 wt%, preferably from 2 wt% to 15 wt%, more preferably from 5 wt% to 10 wt%; and the percentage by weight of the at least one additive (v) ranges from 0 wt% to 10 wt%, preferably from 2 wt% to 15 wt%, more preferably from 5 wt% to 10 wt%; being the sum of the percentages equal to 100%.

[0076] In an embodiment, the non-metallic and compostable twist-tie is prepared from a composition wherein the copolymer (II) is one of formula (I) as described above, wherein the percentage by weight of the first block (PLA) ranges from 40 % to 90%, preferably from 50 % to 70%; and the percentage by weight of the second block ranged from 10% to 60%, preferably from 30 % to 50%; being the sum equal to 100%; being the first block and second block as defined above.

[0077] In some embodiments the initiator is monofunctional methoxy diethylene glycol, (C2-C20) alkanol. In some embodiments, the initiator is selected from CH3-(CH2)y-OH being y an integer from 1 to 19, preferably from 1 to 15, more preferably from 1 to 11 . In some embodiments, the initiator is selected from monofunctional methoxy diethylene glycol, 1-decanol, ethanol, 1-butanol and dodecanol.

[0078] In some embodiments, the block copolymer (II) is one of formula (I) as defined above, wherein in the second block defined by square bracket with the numerical value n, X is a monomer selected from s-caprolactone.

[0079] In an embodiment, the non-metallic and compostable twist-tie is one wherein the block copolymer (II) is one of formula (la) m is an integer from 50 to 10000, preferably from 100 to 8000, more preferably from 130 to 5000, particularly preferred from 139 to 1.388; n is an integer from 30 to 6000, preferably from 50 to 3000, more preferably from 80 to 1000, particularly preferred from 88 to 876; x is an integer from 1 to 19, preferably from 5 to 15, more preferably from 7 to 11 .

[0080] In an embodiment, the non-metallic and compostable twist-tie is one wherein the block copolymer (II) is one of formula (la) as defined above; and the percentage by weight of the poly (L-lactide) homopolymer (i) ranges from 55 wt% to 97 wt%, preferably from 60 wt% to 96 wt%, more preferably from 70 wt% to 95 wt%; the percentage by weight of the at least one copolymer (ii) ranges from 3 wt% to 20 wt%, preferably from 4 wt% to 18 wt%, more preferably from 5 wt% to 15 wt%; the percentage by weight of the at least one additional biodegradable copolymer (iii) ranges from 0 wt% to 20 wt%, preferably from 2 wt% to 15 wt%, more preferably from 5 wt% to 10 wt%; the percentage by weight of the at least one additional biodegradable homopolymer (iv) ranges from 0 wt% to 20 wt%, preferably from 2 wt% to 15 wt%, more preferably from 5 wt% to 10 wt%; and the percentage by weight of the at least one additive (v) ranges from 0 wt% to 10 wt%, preferably from 2 wt% to 15 wt%, more preferably from 5 wt% to 10 wt%; being the sum of the percentages equal to 100%.

[0081] In an embodiment, the non-metallic and compostable twist-tie is prepared from a composition wherein the copolymer (ii) is one of formula (la) as described above, wherein the percentage by weight of the first block (PLA) ranges from 40 % to 90%, preferably from 50 % to 70%; and the percentage by weight of the second block ranged from 10% to 60%, preferably from 30 % to 50%; being the sum equal to 100%; being the first block and second block as defined above.

[0082] In an embodiment, the non-metallic and compostable twist-tie is one wherein the block copolymer (ii) is one of formula (la), m is from 139 to 1.388, thereby the number average molecular weight (Mn) of the poly(L-lactide) block is from 20.000 to 200.000 g / mol measured by GPC; and n is from 88 to 876, thereby the number average molecular weight (Mn) of the second block is from 10.000 to 100.000 g / mol measured by GPC.

[0083] In an embodiment, the non-metallic and compostable twist-tie is one wherein in the block copolymer (ii) is one of formula (la), m is from 243 to 416, thereby the number average molecular weight (Mn) of the poly (L-lactide) block is from 35.000 to 60.000 g / mol measured by GPC; and n is from 140 to 263, thereby the number average molecular weight (Mn) of the second block is from 16.000 to 30.000 g / mol measured by GPC.

[0084] In an embodiment, the non-metallic and compostable twist-tie is one wherein in the block copolymer (ii) is one of formula (la), m is from 139 to 1.388, thereby the number average molecular weight (Mn) of the poly( / _- lactide) block is from 20.000 to 200.000 g / mol measured by GPC; n is from 88 to 876, thereby the number average molecular weight (Mn) of the second block is from 10.000 to 100.000 g / mol measured by GPC; and the molar ratio between the poly( / _-lactide) block and the second block is 2:1.

[0085] In an embodiment, the non-metallic and compostable twist-tie is one wherein in the block copolymer (ii) is one of formula (la), m is from 243 to 416, thereby the number average molecular weight (Mn) of the poly (L-lactide) block is from 35.000 to 60.000g / mol measured by GPC; n is from 140 to 263, thereby the number average molecular weight (Mn) of the second block is from 16.000 to 30.000 g / mol measured by GPC; and the molar ratio between the poly(Z_-lactide) block and the second block is 2:1.

[0086] In an embodiment, the non-metallic and compostable twist-tie is one wherein in the block copolymer (ii) is one of formula (la), m is from 139 to 1.388, thereby the number average molecular weight (Mn) of the poly(Z_- lactide) block is from 20.000 to 200.000 g / mol measured by GPC; n is from 88 to 876, thereby the number average molecular weight (Mn) of the second block is from 10.000 to 100.000 g / mol measured by GPC; and the melting temperature of the PLLA block of the block copolymer of the present invention (Tm- PLLA) is from 167 to 168 °C.

[0087] In an embodiment, the non-metallic and compostable twist-tie is one wherein in the block copolymer (II) is one of formula (la), m is from 243 to 416, thereby the number average molecular weight (Mn) of the poly ( / .-lactide) block is from 35.000 to 60.000g / mol measured by GPC; n is from 140 to 263, thereby the number average molecular weight (Mn) of the second block is from 16.000 to 30.000 g / mol measured by GPC; and the melting temperature of the PLLA block of the block copolymer of the present invention (Tm- PLLA) is from 167 to 168 °C.

[0088] In an embodiment, the non-metallic and compostable twist-tie is one wherein in the block copolymer (II) is one of formula (la), m is from 139 to 1.388, thereby the number average molecular weight (Mn) of the poly(Z_- lactide) block is from 20.000 to 200.000 g / mol measured by GPC; n is from 88 to 876, thereby the number average molecular weight (Mn) of the second block is from 10.000 to 100.000 g / mol measured by GPC; the molar ratio between the polyfL-lactide) block and the second block is 2:1; and the melting temperature of the PLLA block of the block copolymer of the present invention (T m- PLLA) is from 167 to 168 °C.

[0089] In an embodiment, the non-metallic and compostable twist-tie is one wherein in the block copolymer (II) is one of formula (la), m is from 243 to 416, thereby the number average molecular weight (Mn) of the poly ( / .-lactide) block is from 35.000 to 60.000g / mol measured by GPC; n is from 140 to 263, thereby the number average molecular weight (Mn) of the second block is from 16.000 to 30.000 g / mol measured by GPC; the molar ratio between the poly(Z_-lactide) block and the second block is 2:1; and the melting temperature of the PLLA block of the block copolymer of the present invention (Tm- PLLA) is from 167 to 168 °C.

[0090] For the purpose of the invention, “m” refers to the degree of polymerization of poly ( / .-lactide) block and it is defined as the number of monomer units in the poly(L-lactide) block. Particularly, “m” is calculated as the ratio of the number-average molecular weight (Mn) of the poly ( / .-lactide) block and the monomer molecular weight (Mo) of the repeat unit (L-lactide) as it is shown in the following formula: Further, for the purpose of the invention “n” is the degree of polymerization of the second block and it is defined as the number of monomer units in the block. Particularly, “n” It is calculated as the ratio of the number-average molecular weight (Mn) of the block and the monomer molecular weight of the repeat unit which is selected from s-caprolactone, butylene succinate, butylene succinate adipate, hydroxybutyric acid, and hydroxyvaleric acid as it is show in the following formula:

[0091] The terms "number average molecular weight”, "number average molar mass” and the abbreviature "Mn” have the same meaning and they are used interchangeable. Mn is a way of determining the molecular mass of a polymer. Polymer molecules, even ones of the same type, come in different sizes (chain lengths, for linear polymers), so the average molecular mass will depend on the method of averaging. The number average molecular mass is the ordinary arithmetic means or average of the molecular masses of the individual macromolecules. It is determined by measuring the molecular mass of n polymer molecules, summing the masses, and dividing by n. The Mn is calculated by the following formula: wherein A / , is the number of molecules of molecular mass M,.

[0092] The number average molecular mass of a polymer can be determined by gel permeation chromatography (GPC), viscometry via the (Mark-Houwink equation), coll igative methods such as vapor pressure osmometry, end-group determination or proton NMR. For the purpose of the invention the Mn is measured by GPC.

[0093] The terms "monomer molecular weight”, "the molecular weight of the monomer” and the abbreviature "Mo” have the same meaning and they are used interchangeable. Mo is a way of determining the molecular mass of a monomer. It is calculated as the sum of the atomic weights of the individual atoms that comprise the monomeric unit. The molecular weight of / .-lactide is taken as 144,13 g / mol while the molecular weight of s- caprolactone is taken as 114,14 g / mol.

[0094] For the purpose of the invention, the terms "polymer" and "polymeric" refer to compounds that are obtained from a polymerization reaction. These terms include homopolymers and copolymers. The term "homopolymer” refers to polymers obtained by polymerizing only one kind of monomer. Meanwhile, the term "copolymer” refers to polymers obtained by polymerizing two or more different kinds of monomers. Furthermore, the term "block copolymer" refers to a polymer comprising two or more homopolymer subunits linked by covalent bonds. Therefore, a block copolymer is made of blocks of different polymerized monomers.

[0095] For the purpose of the present invention, the term "poly (L-lactide)” or "PLLA” is the polymer resulting from the polymerization of L-lactide, and the term “poly / _-lactide) block” refers to the subunit formed by the homopolymer of PLLA. Further, the term "poly(s-caprolactone)” or "PCL” is the polymer resulting from the polymerization of s-caprolactone having the CAS number 24980-41-4, and the term "poly(s-caprolactone) block” refers to the subunit formed by the homopolymer of PCL. The term "polybutylene succinate” or "BPS” is the polymer resulting from the polymerization of butylene succinate, and the term "polybutylene succinate block” refers to the subunit formed by the homopolymer of PBS. The term "polybutylene succinate adipate” or "PBSA” is the polymer resulting from the polymerization of butylene succinate and adipic acid, and the term "polybutylene succinate adipate block” refers to the subunit formed by the homopolymer of PBSA. The term "polyhydroxybutyric acid” or "PHB” is the polymer resulting from the polymerization of hydroxybytyric acid, and the term "polyhydroxybutyric acid block” refers to the subunit formed by the homopolymer of PHB. The term "polyhydroxyvaleric acid” or "PHV” is the polymer resulting from the polymerization of hydroxyvaleric acid, and the term "polyhydroxyvaleric acid block” refers to the subunit formed by the homopolymer of PHV. The term "polyhydroxybutyric acid-co-polyhydroxyvaleric acid” or (PHBV) is the copolymer resulting from the polymerization of polyhydroxybutyric acid and polyhydroxyvaleric acid monomers, and the term "polyhydroxybutyric acid - co- polyhydroxyvaleric acid block” refers to the subunit formed by the copolymer PHBV.

[0096] The term "polylactide based copolymers” and "poly(s-caprolactone) based copolymers” are those copolymers resulting from the polymerization of a poly (L-lactide) block or a poly(s-caprolactone) block and a second block selected from poly(s-caprolactone) block, polyhydroxybutyric acid block, polyhydroxyvaleric acid block, and polyhydroxybutyric acid - co- polyhydroxyvaleric acid block.

[0097] The non-metallic tie is prepared from a composition as defined above which optionally may comprise additives. The additives used in the composition of the invention do not significantly modify the properties of the block copolymer of formula (I). Examples of appropriate additives includes, but not limited to binders, antioxidants (such as tartaric acid and succinic anhydride), nucleating agents, plasticizers, dyes, pigments, flame-resistant agents, reinforcing agents, ultraviolet ray absorbent agents, heat stabilizers, releasing agents, surface wettability improving agent, fillers selected from organic fillers (such as starch, cellulose, and derivatives thereof) and inorganic fillers (such as silica, calcium carbonate, talc, kaolin, kaolinite, titanium oxide, zinc oxide and the like). The appropriate additives, and their amounts, can readily be determined by those skilled in the art according to the type of composition being prepared.

[0098] In one embodiment, the non-metallic and compostable twist-tie according to the present invention exhibits a flexural modulus ranging from 2000-3800 MPa, preferably from 2200-3000 MPa, more preferably from 2300- 2900 MPa, when analysed according to ISO 178 standard. In one embodiment, the non-metallic and compostable twist-tie according to the present invention exhibits a Young modulus ranging from 2000-3800 MPa, preferably from 2200-3200 MPa, more preferably from 2400- 3000 MPa, when analysed according to ISO 527-2 standard.

[0099] In one embodiment, the non-metallic and compostable twist-tie according to the present invention exhibits a filament tenacity ranging from 2.5-4.5 gf / den, preferably from 2.5-3.5 gf / den, preferably from 2.7-3.5 gf / den, more preferably from 2.8-3.5 gf / den, when analysed according to ISO 2062:2009 standard.

[0100] In one embodiment, the non-metallic and compostable twist-tie according to the present invention exhibits an elongation at breakage ranging from 10-80%, preferably from 15-60 %, more preferably from 20-50 % when analysed according to the ISO527-3 standard.

[0101] In one embodiment, the non-metallic and compostable twist-tie exhibits a tensile strength at yield ranging from 40-50 MPa, preferably from 42-48 MPa, more preferably from 44-46 MPa when analysed according to the ISO527-3 standard.

[0102] In one embodiment, the non-metallic and compostable twist-tie exhibits a tensile strength at breakage ranging from 20-55 MPa, preferably from 25-45 MPa, more preferably from 29-40 MPa, when analyzed according to the ISO 527-3 standard.

[0103] In one embodiment, the non-metallic and compostable twist-tie according to the present invention exhibits a tenacity at break ranging from 18 to 40 cN / tex, preferably from 20-38 cN / tex, more preferably from 22-35 cN / tex, when analyses according to ISO 2062:2009 standard.

[0104] In one embodiment, the non-metallic and compostable twist-tie according to the present invention exhibits filament tenacity ranging from 2.5-4.5 gf / den, preferably from 2.5-3.5 gf / den, preferably from 2.7-3.5 gf / den, more preferably from 2.8-3.5 gf / den; and tenacity at break ranging from 18 to 40 cN / tex, preferably from 20-38 cN / tex, more preferably from 22-35 cN / tex.

[0105] In one embodiment, the non-metallic and compostable twist-tie exhibits the following properties: flexural modulus ranging from 2000-3800 MPa, preferably from 2200-3000 MPa, more preferably from 2300-2900 MPa;

[0106] Young modulus ranging from 2000-3800 MPa, preferably from 2200-3000 MPa, more preferably from 2400-3000 MPa; elongation at breakage ranging from 10-80%, preferably from 15-60 %, more preferably from 20- 50 %; and tensile strength at breakage ranging from 20-55 MPa, preferably from 25-45 MPa, more preferably from 29-40 MPa. In one embodiment, the non-metallic and compostable twist-tie exhibits the following properties: flexural modulus ranging from 2000-3800 MPa, preferably from 2200-3000 MPa, more preferably from 2300-2900 MPa;

[0107] Young modulus ranging from 2000-3800 MPa, preferably from 2200-3000 MPa, more preferably from 2400-3000 MPa; filament tenacity ranging from 2.5-4.5 gf / den, preferably from 2.5-3.5 gf / den, preferably from 2.7- 3.5 gf / den, more preferably from 2.8-3.5 gf / den; elongation at breakage ranging from 10-80%, preferably from 15-60 %, more preferably from 20- 50 %; tensile strength at breakage ranging from 20-55 MPa, preferably from 25-45 MPa, more preferably from 29-40 MPa.

[0108] In one embodiment, the non-metallic and compostable twist-tie exhibits the following properties: flexural modulus ranging from 2000-3800 MPa, preferably from 2200-3000 MPa, more preferably from 2300-2900 MPa;

[0109] Young modulus ranging from 2000-3800 MPa, preferably from 2200-3000 MPa, more preferably from 2400-3000 MPa; elongation at breakage ranging from 10-80%, preferably from 15-60 %, more preferably from 20- 50 %; filament tenacity ranging from 2.5-4.5 gf / den, preferably from 2.5-3.5 gf / den, preferably from 2.7- 3.5 gf / den, more preferably from 2.8-3.5 gf / den; tenacity at break ranging from 18 to 40 cN / tex, preferably from 20-38 cN / tex, more preferably from 22-35 cN / tex; and tensile strength at breakage ranging from 20-55 MPa, preferably from 25-45 MPa, more preferably from 29-40 MPa.

[0110] In an embodiment, the non-metallic and compostable twist-tie is one wherein the density of the block copolymer is from 200 to 600 (Pa'S) / 180°C, preferably from 220 to 550 (Pa'S) / 180°C, more preferably from 250-500 (Pa'S) / 180°C. Viscosity of the block copolymer of the present invention can be measured by any method known in the state of the art. For the purpose of the present invention the viscosity is measured by employing a DHR, Discovery Hybrid Rheometer (TA Instruments, New Castle, DE, USA).

[0111] In an embodiment, the non-metallic and compostable twist-tie is one wherein the residual / .-lactide content is from 1 to 4% by weight in relation to the total weight of the block copolymer. In an embodiment, the non- metallic and compostable twist-tie is one wherein the residual / .-lactide content is up to 5% by weight in relation to the total weight of the block copolymer. In an embodiment, the non-metallic and compostable twisttie is one wherein the residual / .-lactide content is about 3% by weight in relation to the total weight of the block copolymer. The residual / .-lactide content of the block copolymer of the present invention can be measured by any method known in the state of the art. For the purpose of the present invention the residual / .-lactide content is quantitatively measured by thermogravimetric analysis employing a TGA Q-500 thermogravimetric equipment (TA Instruments, New Castle, DE, USA).

[0112] In an embodiment, the non-metallic and compostable twist-tie is one wherein the at least one block copolymer (II) is one having a number average molecular weight (Mn) is from 30.000 to 500.000 g / mol measured by gel permeation chromatography (GPC). In an embodiment, the non-metallic and compostable twist-tie is one wherein the block copolymer (II) has a number average molecular weight (Mn) is from 35.000 to 200.000 g / mol measured by gel permeation chromatography (GPC). In an embodiment, the non-metallic and compostable twist-tie is one wherein the block copolymer (II) has a number average molecular weight (Mn) from 40.000 to 100.000 g / mol measured by gel permeation chromatography (GPC). In an embodiment, the non-metallic and compostable twist-tie is one wherein the block copolymer (II) has a number average molecular weight (Mn) from 45.000 to 70.000 g / mol measured by gel permeation chromatography (GPC). In an embodiment, the non-metallic and compostable twist-tie is one wherein the block copolymer (II) has a number average molecular weight (Mn) from 50.000 to 60.000 g / mol measured by gel permeation chromatography (GPC).

[0113] As it is mentioned above, the non-metallic and compostable twist-tie is one wherein the block copolymer (II) is one of formula (la) wherein m is an integer from 50 to 10000, preferably from 100 to 8000, more preferably from 130 to 5000, particularly preferred from 139 to 1.388, thereby the number average molecular weight (Mn) of the poly ( / .-lactide) block is from 20.000 to 200.000 g / mol measured by GPC. In an embodiment, the non- metallic and compostable twist-tie is one wherein the block copolymer (ii) is one of formula (la) wherein m is from 173 to 694, thereby the number average molecular weight (Mn) of the polyfL-lactide) block is from 25.000 to 100.000 g / mol measured by GPC. In an embodiment, the non-metallic and compostable twist-tie is one wherein the block copolymer (ii) is one of formula (la) wherein m is from 208 to 555, thereby the number average molecular weight (Mn) of the polyfL-lactide) block is from 30.000 to 80.000 g / mol measured by GPC. In an embodiment, the non-metallic and compostable twist-tie is one wherein the block copolymer (ii) is one of formula (la) wherein m is from 243 to 416, thereby the number average molecular weight (Mn) of the polyfL- lactide) block is from 35.000 to 60.000 g / mol measured by GPC. In an embodiment, the non-metallic and compostable twist-tie is one wherein the block copolymer (ii) is one of formula (la) wherein m is from 264 to 347, thereby the number average molecular weight (Mn) of the poly ( / .-lactide) block is from 38.000 to 50.000 g / mol measured by GPC. In an embodiment, the non-metallic and compostable twist-tie is one wherein the block copolymer (ii) is one of formula (la) wherein m is about 278, thereby the number average molecular weight (Mn) of the poly ( / .-lactide) block is about 40.000 g / mol measured by GPC.

[0114] As it is mentioned above, the non-metallic and compostable twist-tie is one wherein the block copolymer (ii) is one of formula (la) wherein n is an integer from 30 to 6000, preferably from 50 to 3000, more preferably from 80 to 1000, particularly preferred from 88 to 876, thereby the number average molecular weight (Mn) of the second block is from 10.000 to 100.000 g / mol measured by GPC. In an embodiment, the non-metallic and compostable twist-tie is one wherein the block copolymer (ii) is one of formula (la) wherein n is from 105 to 613, thereby the number average molecular weight (Mn) of the second block is from 12.000 to 70.000 g / mol measured by GPC. In an embodiment, the non-metallic and compostable twist-tie is one wherein the block copolymer (II) is one of formula (la) wherein n is from 123 to 438, thereby the number average molecular weight (Mn) of the second block is from 14.000 to 50.000 g / mol measured by GPC. In an embodiment, the non-metallic and compostable twist-tie is one wherein the block copolymer (II) is one of formula (la) wherein n is from 140 to 263, thereby the number average molecular weight (Mn) of the second block is from 16.000 to 30.000 g / mol measured by GPC. In an embodiment, the non-metallic and compostable twist-tie is one wherein the block copolymer (II) is one of formula (la) wherein n is from 158 to 219, thereby the number average molecular weight (Mn) of the second block is from 18.000 to 25.000 g / mol measured by GPC. In an embodiment, the non-metallic and compostable twist-tie is one wherein the block copolymer (II) is one of formula (la) wherein n is about 1 5, thereby the number average molecular weight (Mn) of the second block is about 20.000 g / mol measured by GPC.

[0115] In an embodiment, the non-metallic and compostable twist-tie is one wherein the block copolymer (II) is one of formula (la) and the molar ratio between the polyfL-lactide) block and the second block is from 3:1 to 1 :1. In an embodiment, the block copolymer is one wherein the molar ratio between the polyf / _-lactide) block and the second block is 2:1.

[0116] In some embodiments, the length of the non-metallic tie may vary according to application. In certain embodiments, the length may vary from about 1 cm to about 40 cm; from about 1 to about 20 cm; or from about 1 to about 15, 14, 13, 12, 11, 10, 9, 8, 7, 6, 5, 4, 3 or 2 cm. Other lengths are possible, depending on the application. The material of the tie may be provided in a roll of material which may be conveniently cut into shorter segments.

[0117] In some embodiments, the cross-section of the non-metallic tie, which is preferably uniform for the length of the tie, may have any desired shape, The cross-section may comprise, for example, the following shapes: rectangle, square, circle, oval, half-moon, or any other geometric configuration. In one embodiment, the tie has a preferably circular cross-section.

[0118] In some particular embodiments, the non-metallic tie has a circular cross-section and forms a filament having a diameter of from about 0.2 to about 2 mm, preferably from about 0.5 to about 1 .5 mm, more preferably from 0.7 to about 1, 0.6, 0.7, 0.8, or 0.9 mm.

[0119] In some embodiments, the non-metallic tie is adapted to be deformed from an initial conformation in the form of a ribbon or filament of the indicated cross-section, to the conformation of releasable closure. As a twist-tie, the tie is able to undergo repeated closures by twisting and untwisting. As a tin-tie, the tie is able to undergo repeated closures by bending and unbending.

[0120] As it is mentioned above, the second aspect of the invention is a method for the preparation of the non- metallic and compostable twist-tie of the first aspect of the invention, the method comprising:

[0121] (a) preparing a composition comprising:

[0122] (i) a poly (L-lactide) homopolymer;

[0123] (ii) at least one biodegradable copolymer;

[0124] (iii) optionally at least one biodegradable homo- or copolymer other than (i) or (ii); and

[0125] (iv) optionally at least one additive. wherein the components (i), (ii), (iii) and (iv) are as described above;

[0126] (b) shaping the composition to form the non-metallic and compostable twist-tie.

[0127] In some embodiments, the shaping step (b) comprises a monofilament extrusion process, where after the extrusion process, alternate at least two consecutive series of cooling steps and stretching stage.

[0128] Cooling steps may be performed by air cooling (e.g. using an oven) or using a cooling bath, which comprises dipping the extruded monofilament into a liquid medium, preferably water.

[0129] In some embodiments, the extrusion process is carried out at a temperature ranging from 170-200°C, preferably 190-200°C.

[0130] In some embodiments, the shaping step comprises a consecutive series of a first cooling step at a temperature ranging from 20-60°C, preferably from 50-80 °C; a first stretching step; a second cooling step at a temperature ranging from 35-50°C; and a second stretching step.

[0131] In some embodiments, the shaping step comprises a consecutive series of a first cooling step at a temperature ranging from 65-100 °C; a first stretching step; a second cooling step at a temperature ranging from 35-65°C; a second stretching step; a third cooling step at a temperature ranging from 20-35°C; and a third stretching step.

[0132] To cool the molten material a cooling bath is always required, and then to do the filament drawing both systems, air and water heating may be used. Air cooling, in e.g. an oven, may be used to cool the molten material in the extrusion stage. In some embodiments, the cooling and the consecutive heating are gradual so that the stretching can be generated correctly, a stage where a rearrangement of the polymeric chains is achieved, which allows the material to obtain better mechanical properties such as toughness.

[0133] It is noted that both cooling and drawing steps affects directly to the mechanical properties of the material. Mechanical properties of a polymeric material strongly depend on the processing conditions, especially when alternating phases of cooling and drawing are applied. These processes affect the polymer's nano and microstructure at the molecular level, modifying its crystallinity, chain orientation, and internal stress distribution. Both, cooling and drawing regulates the degree of crystallization and the distribution of amorphous and crystalline phases, due to the different temperatures allow different polymeric chains mobility, and the drawing at the same time promotes the alignment of the molecular chains, increasing the order of the polymeric molecules as well as the crystallinity, impacting its mechanical behaviour. When the material is stretched, polymer chains align in the direction of deformation, increasing tensile strength and reducing elongation at break.

[0134] In accordance with some embodiments, depending on the material and the objectives of improving properties, it may be necessary to carry out a first cooling stage with a subsequent stage of a new slight heating (temperature above Tg) that allows the polymeric chains to have movement and a correct stretching can be achieved, therefore the subsequent baths can be replaced by air ovens, which will be understood as a production system by air cooling.

[0135] In some embodiments, the first, second and successive stretching steps are carried out by drawing speed from 1 to 150 m / min, preferably from 8 to 140 m / min until a draw ratio from 1.5 to 12 m / min, preferably from 3.5 to 10 m / min is obtained. In one embodiment, the draw ratio is preferably from 7 to 10 m / min.

[0136] Stretching steps usually always follow the guidelines of initially increasing the strength or stretching of the monofilament, and in the last stage of stretching is left with very low or no stretching, this stage is called the stage of relaxation of the filament.

[0137] The preferred stretching conditions will depend on the final formula, preferably will be to reach high stretching ratios, that is to say that the difference between tensor 1 and 2 is as high as possible, achieving high stretching and with them better tenacities. This will always depend on the cooling conditions and possible slight heating in the baths and / or ovens used in the production process.

[0138] In some embodiments, the non-metallic tie according to the present invention comprises at least three stretching stages, preferably including at least one cooling by air.

[0139] Some particular embodiments related to the cooling step are mentioned in table 1 :

[0140] Table 1

[0141] Some particular embodiments are prepared following the following conditions:

[0142] Table 2

[0143] Thus, the non-metallic and compostable twist-tie of the first aspect of the invention is obtainable by a process as defined above and below is also part of the invention.

[0144] For the purposes of the invention the expressions "obtainable", "obtained" and equivalent expressions are used interchangeably, and in any case, the expression "obtainable" encompasses the expression "obtained".

[0145] The applications of the non-metallic and compostable twist-tie according to the present invention are for closures of packaged products; as a fastener to tying products, e.g. to be placed directly around the products itself (e.g. such as to fastening agricultural products such as to fasten plants to stakes; or to secure bundled electric cable) and other fastening tasks.

[0146] Throughout the description and claims the word "comprise" and variations of the word, are not intended to exclude other technical features, additives, components, or steps. Furthermore, the word "comprise” encompasses the case of "consisting of'. Additional objects, advantages and features of the invention will become apparent to those skilled in the art upon examination of the description or may be learned by practice of the invention. The following examples are provided by way of illustration, and they are not intended to be limiting of the present invention. Furthermore, the present invention covers all possible combinations of particular and preferred embodiments described herein.

[0147] Examples

[0148] Abbreviature

[0149] PLA-b-PCL: block copolymer of poly ( / .-lactide) and poly(s-caprolactone)

[0150] PLLA: poly( / _-lactide) PLA: poly(lactide)

[0151] PCL: poly(s-caprolactone)

[0152] PBS: polybutylene succinate

[0153] Material and methods

[0154] All the reagents and solvents used in the present application are commercially available.

[0155] PLA LX 175 is a poly(L-lactide) homopolymer supplied by Total Corbion PLA

[0156] ADBio PLA+ is a poly(L-lactide)-co-poly(s-caprolactone) block copolymer supplied by ADBIOPLASTICS.

[0157] PBS is a polybutylene succinate polymer supplied by MITSUBISHI QUIMICAL GROUP

[0158] The Number average molecular weight (Mn) of the copolymers was measured by employing the Malvern OMNISEC gel-permeation / size-exclusion chromatography (GPC / SEC).

[0159] The Melting point was measured by differential scanning calorimetry (DSC) using a DSC 0-2000 calorimeter (TA Instruments, New castle, DE, USA).

[0160] The melt flow index (MFI) of the compositions of the present invention was measured by using a melt flow indexer Gbttefert MI-3 (GOTTFERT Werkstoff-Prufmaschinen GmbH, Germany)

[0161] Degradation temperature was measured by thermogravimetric analysis employing a TGA Q-500 thermogravimetric equipment (TA Instruments, New castle, DE, USA)

[0162] Heat deflection temperature (HDT) was measured by dynamo mechanical analysis employing a DMA Q-800 (TA Instruments, New castle, DE, USA).

[0163] The Tensile strength at break (MPa) was measured by tensile tests using a universal testing machine Testometric M350-20CT (Rochdale, UK), equipped with a 100 N load cell.

[0164] The elongation at break was measured by tensile tests using a universal testing machine Testometric M350- 20CT (Rochdale, UK), equipped with a 100 N load cell.

[0165] The flexural modulus (MPa) was measured by running flexural tests in a universal testing machine Testometric M350-20CT (Rochdale, UK).

[0166] Young modulus (MPa) was measuredby tensile tests using a universal testing machine Testometric M350- 20CT (Rochdale, UK), equipped with a 100 N load cell. Filament tenacity (gf / den) was measured using a 3345 model of 3300 series universal Testing Systems of Instron.

[0167] 1. Compositions comprising PLA homopolymer (i) and the copolymer (ii)

[0168] The compositions 1-2 comprising a PLA homopolymer and the block copolymer of Example 3 in form of pellets are listed herein below in Table 3.

[0169] Table 3

[0170] 1.2. Preparation process by extrusion / compounding technique a) Extrusion Step

[0171] Compositions 1-2 were produced by the extrusion technique. Components, ADBio PLA+, PBS and the PLA homopolymer, were mixed in the proportions shown above.

[0172] The compositions were produced in a twin-screw extruder (Coperion ZSK 26MC) with a L / D of 40, using the temperatures profile 195-205, 275 rpm as screw speed, resulting in working pressures between 25-28 bar and torque between 50-60 %. b) Crystallization step

[0173] Following the extrusion step, a crystallization and drying step of the pellets thus obtained was carried out under 90-100°C stirring the pellets continuously. Further, the drying step was done under 100°C and 4h, after that the humidity was analysed by Aquatrac equipment. The humidity of the pellet-composition was below 200-250ppm, taking this value as quality control; as well as the melt flow index (MFI) which was also measured.

[0174] The MFI values expressed as g / 1 Omin of compositions 1-5 and the PLA used as starting material are listed in the table 4 below: Table 4

[0175] 1.3. Mechanical properties

[0176] 1.3.1. By the production of injected moulding technique specimens

[0177] To characterise the thermal and mechanical properties of the compositions 1-2 of the present invention, injected specimens were manufactured through Battenfeld HM 45 / 210 equipment, using a four-cavity mould.

[0178] The pellets of compositions 1-2 obtained above were processed under injection moulding machine to obtain the specimens required in both characterisations. The results of the characterisation of thermal and mechanical properties measured by the production of injected moulding technique specimens are presented in table 12 below. In particular, Table 5 shows the values of the melting point, degradation temperatures and heat deflection temperature (HDT) obtained when the compositions 1-2 were processed in form of injected moulding technique specimens.

[0179] Table 5

[0180] The results of the characterisation of mechanical properties measured by the production of cast film extrusion and injected moulding specimens are presented in table 6 below.

[0181] Table 6

[0182] As it shown in the above-mentioned results, the elongation at break increases when the block copolymer of formula (I) is added on the PLA, reaching the maximum value (6%) of elongation when 15-20% of block copolymer of formula (I) is incorporated, obtaining Young Modulus values in the same range. Furthermore, even of having a slightly decrease in the values of the tensile strength at yield and flexural modulus, as the elongation at break increase, and the Young Modulus are in the same range, it can be stated that the compositions of the invention comprising the block copolymer of formula (I) have an enhanced tenacity and flexibility in comparison to PLA, removing its undesirable brittleness.

[0183] Furthermore, the most important properties of the monofilament to apply as twist band are the tensile properties measured on monofilament. In this case, relevant properties that can assure that the twist band resists many times to the torsion effect are the tenacity and the elongation at break. Higher draw ratio allows higher tenacity, decreasing as the same time the elongation at break, due to higher tenacity is reached by high draw ratio which implies lower elongation at break. The mechanical properties of the monofilament produced with different composition are showed in the table below.

[0184] Table 7

[0185] Thus, the above-mentioned results demonstrate that the presence of the block copolymer of formula (I) of the present invention improve the mechanical properties of the PLA, without compromising its thermal properties.

[0186] 1.3.2. Food contact compliance evaluation To achieve food-contact materials, studies of global and specific migrations of restricted chemical substances were performed following the European legislation of the EURegulation 10 / 2011 (COMMISSION REGULATION (EU) No 10 / 2011 of 14 January 2011 on plastic materials and articles intended to come into contact with food; available on June 11th, 2021 in https: / / eur-lex.europa.eu / legal- content / EN / TXT / PDF / ?uri=CELEX:32011R0010&from=es).

[0187] In this case, the specific migrations of the Compositions 1-2 of the present invention were evaluated at different conditions (frozen long term, refrigerated long term and room temperature less than 30 days, room temperature between 1-6 months and room temperature more than 6 months) and with several simulants (simulants A, B, C, D2 and E as disclosed in page 75 of the same legislation EU 10 / 2011).

[0188] After performing the evaluation of the restricted substances migrations, the compositions of the present invention complies to food preserved under frozen and refrigerated conditions for long term; and room temperature for less than 30 days for all the tested simulants. Furthermore, the compositions of the present invention are especially advantageous because also complies to food preserved at room temperature between 1-6 months for tested simulants B, D2 and E; and even at room temperature for more than 6 months also for simulants D2 and E.

[0189] Therefore, the above-mentioned results demonstrate that the compositions of the present invention which comprises the block copolymer of the first aspect of the invention comply with the current European regulation about food contact and they are appropriate for being used in contact with food.

[0190] For reasons of completeness, various aspects of the invention are set out in the following numbered clauses:

[0191] Clause 1. A non-metallic and compostable twist-tie prepared from a composition comprising:

[0192] (I) a poly (L-lactide) homopolymer;

[0193] (II) at least one biodegradable copolymer selected from a polylactide based copolymer, a poly (s- caprolactone) based copolymer, a copolymer of polybutylene adipate-co-terephthalate (PBAT), a copolymer of p-hydroxybutyric acid and p-hydroxyvaleric acid (PHBV), and a copolymer of polybutylene succinate adipate (PBSA);

[0194] (ill) optionally at least one additional biodegradable and compostable homopolymer selected from a homopolymer of poly(s-caprolactone), a homopolymer of polybutylene succinate, a homopolymer of polyhydroxybutyric acid, a homopolymer of polyhydroxyvaleric acid; and

[0195] (iv) optionally at least one additive; wherein the polylactide based copolymer is a polymer prepared from at least two different monomers being one of them selected from L-lactide, D-lactide and LD-lactide, and the second monomer being selected from s-caprolactone, butylene succinate; hydroxybutyric acid, hydroxyvaleric acid; and polybutylene succinate adipate; wherein the poly(s-caprolactone) based copolymer, is a polymer prepared from at least two different monomers being one of them s-caprolactone (PCL), and the second monomer being selected from lactic acid, butylene succinate; hydroxybutyric acid, hydroxyvaleric acid, and polybutylene succinate adipate.

[0196] Clause 2. The non-metallic and compostable twist-tie according to clause 1, wherein the composition comprises:

[0197] (i) a poly (L-lactide) homopolymer;

[0198] (ii) at least one biodegradable polylactide based copolymer;

[0199] (iii) optionally at least one additional biodegradable copolymer selected from a poly(s-caprolactone) based copolymer, a copolymer of polybutylene adipate-co-terephthalate (PBAT), a copolymer of p-hydroxybutyric acid and p-hydroxyvaleric acid (PHBV), and a copolymer of polybutylene succinate adipate (PBSA);

[0200] (iv) optionally at least one biodegradable homopolymer selected from a homopolymer of poly (s- caprolactone), a homopolymer of polybutylene succinate, a homopolymer of polyhydroxybutyric acid, a homopolymer of polyhydroxyvaleric acid; and

[0201] (v) optionally at least one additive; wherein the polylactide based copolymer and the poly(s-caprolactone) based copolymer are as defined in clause 1.

[0202] Clause 3. The non-metallic and compostable twist-tie according to any of the clauses 1-2, wherein the composition comprises:

[0203] (I) a poly (L-lactide) homopolymer;

[0204] (ii) at least one biodegradable poly(L-lactide)-co-polycaprolactone (PLA-b-PCL) block copolymer;

[0205] (iii) optionally at least one additional biodegradable copolymer selected from a poly(s-caprolactone) based copolymer, a copolymer of polybutylene adipate-co-terephthalate (PBAT), a copolymer of P-hydroxybutyric acid and p-hydroxyvaleric acid (PHBV), and a copolymer of polybutylene succinate adipate (PBSA);

[0206] (iv) optionally at least one biodegradable homopolymer selected from a homopolymer of poly (s- caprolactone), a homopolymer of polybutylene succinate, a homopolymer of polyhydroxybutyric acid, a homopolymer of polyhydroxyvaleric acid; and

[0207] (v) optionally at least one additive; wherein the poly(s-caprolactone) based copolymer is as defined in clause 1.

[0208] Clause 4. The non-metallic and compostable twist-tie according to any of the clauses 1-3, wherein the copolymer (ii) is a polylactide based block copolymer wherein the percentage by weight of the first block ranges from 40 % to 90; and the percentage by weight of the second block ranged from 10% to 60%; being the sum equal to 100%.

[0209] Clause 5. The non-metallic and compostable twist-tie according to any of the clauses 1-4, wherein the poly (L- lactide) homopolymer (I) has a number average molecular weight (Mn) ranging from 20000 to 500000 g / mol measured by gel permeation chromatography (GPC); the at least one biodegradable copolymer (II) has a number average molecular weight (Mn) ranging from 30000 to 300000 g / mol measured by gel permeation chromatography (GPC); the optional at least one biodegradable copolymer (ill) has a number average molecular weight (Mn) ranging from 50000 to 300000 g / mol measured by gel permeation chromatography (GPC); and the optional at least one biodegradable homopolymer (iv) has a number average molecular weight (Mn) ranging from 20000 to 500000 g / mol measured by gel permeation chromatography (GPC).

[0210] Clause 6. The non-metallic and compostable twist-tie according to any of the clauses 1-5, wherein the block copolymer (II) is one of formula (I): wherein: m is an integer from 50 to 10000, preferably from 100 to 8000, more preferably from 130 to 5000, particularly preferred from 139 to 1.388; n is an integer from 30 to 6000, preferably from 50 to 3000, more preferably from 80 to 1000, particularly preferred from 88 to 876; wherein in the second block defined by square bracket with the numerical value n, X is a repeating unit selected from s-caprolactone, butylene succinate, butylene succinate adipate, hydroxybutyric acid, and hydroxyvaleric acid; wherein the first block defined by square bracket with the numerical value m, the polylactide monomer is selected from L-lactide, D-lactide and LD-lactide. wherein In is a radical derived from a proper initiator.

[0211] Clause 7. The non-metallic and compostable twist-tie according to clause 6, wherein the percentage by weight of the poly (L-lactide) homopolymer (I) ranges from 55 wt% to 97 wt%; the percentage by weight of the at least one biodegradable copolymer (II) ranges from 3 wt% to 20 wt; the percentage by weight of the at least one additional biodegradable copolymer (ill) ranges from 0 wt% to 20 wt; the percentage by weight of the at least one additional biodegradable homopolymer (iv) ranges from 0 wt% to 20 wt%; and the percentage by weight of the at least one additive (v) ranges from 0 wt% to 10 wt%; being the sum of the percentages equal to 100%.

[0212] Clause 8. The non-metallic and compostable twist-tie according to any of clauses 6-7, wherein the initiator is selected from a monofunctional methoxy diethylene glycol, and an (C2-C20) alkanol.

[0213] Clause 9. The non-metallic and compostable twist-tie according to any of clauses 6-8, wherein the initiator is selected from monofunctional methoxy diethylene glycol, 1 -decanol, ethanol, 1-butanol and dodecanol.

[0214] Clause 10. A process for the preparation of the non-metallic and compostable twist-tie according to any of clauses 1-9, the method comprising:

[0215] (a) preparing a composition comprising:

[0216] (i) a poly (L-lactide) homopolymer;

[0217] (ii) at least one biodegradable copolymer;

[0218] (iii) optionally at least one biodegradable homo- or copolymer other than (I) or (II); and

[0219] (iv) optionally at least one additive. wherein the components (I), (II), (iii) and (iv) are as defined in any of clauses 1-9;

[0220] (b) shaping the composition to form the non-metallic and compostable twist-tie.

[0221] Clause 11. The method according to clause 10, wherein the shaping step (b) comprises a monofilament extrusion process, where after the extrusion process, alternate at least two consecutive series of cooling steps and stretching stage.

[0222] Clause 12. The method according to any of clauses 10-11, wherein cooling steps are performed by air cooling or using a cooling bath, which comprises dipping the extruded monofilament into a liquid medium.

[0223] Clause 13. The method according to any of clauses 10-12, wherein the shaping step comprises a consecutive series of a first cooling step at a temperature ranging from 50-80 °C; a first stretching step; a second cooling step at a temperature ranging from 35-50°C; and a second stretching step.

[0224] Citation List

[0225] 1. UNE-13432 standard

[0226] 2. UNE-14852 standard

[0227] 3. ISO 178 standard

[0228] 4. IS0 18606

Claims

Claims1 . A non-metallic and compostable twist-tie prepared from a composition comprising:(i) a poly (L-lactide) homopolymer;(ii) at least one biodegradable copolymer selected from a polylactide based copolymer, a poly (s- caprolactone) based copolymer, a copolymer of polybutylene adipate-co-terephthalate (PBAT), a copolymer of p-hydroxybutyric acid and p-hydroxyvaleric acid (PHBV), and a copolymer of polybutylene succinate adipate (PBSA);(ill) optionally at least one additional biodegradable and compostable homopolymer selected from a homopolymer of poly(s-caprolactone), a homopolymer of polybutylene succinate, a homopolymer of polyhydroxybutyric acid, a homopolymer of polyhydroxyvaleric acid; and(iv) optionally at least one additive; wherein the polylactide based copolymer is a polymer prepared from at least two different monomers being one of them selected from L-lactide, D-lactide and LD-lactide, and the second monomer being selected from s-caprolactone, butylene succinate; hydroxybutyric acid, hydroxyvaleric acid; and polybutylene succinate adipate; wherein the poly(s-caprolactone) based copolymer, is a polymer prepared from at least two different monomers being one of them s-caprolactone (PCL), and the second monomer being selected from lactic acid, butylene succinate; hydroxybutyric acid, hydroxyvaleric acid, and polybutylene succinate adipate; and wherein the non-metallic twist-tie exhibits the following properties: a. flexural modulus ranging from 2000-3800 MPa, analysed according to ISO 178 standard; b. Young modulus ranging from 2000-3800 MPa, analysed according to ISO 527-2 standard; c. filament tenacity ranging from 2.5-4.5 gf / den, analysed according to ISO 2062:2009 standard; d. elongation at breakage ranging from 10-80%, analysed according to the ISO527-3 standard; and e. tensile strength at breakage ranging from 20-55 MPa, analyzed according to the ISO 527-3 standard.

2. The non-metallic and compostable twist-tie according to claim 1, which exhibits at least one of the following properties: c. filament tenacity ranging from 2.5-4.5 gf / den, analysed according to ISO 2062:2009 standard; and f. tenacity at break ranging from 18-40 cN / tex, analysed according to ISO 2062:2009 standard.

3. The non-metallic and compostable twist-tie according to any of the claims 1-2, wherein the composition comprises:(i) a poly (L-lactide) homopolymer;(ii) at least one biodegradable polylactide based copolymer;(ill) optionally at least one additional biodegradable copolymer selected from a poly(s-caprolactone) based copolymer, a copolymer of polybutylene adipate-co-terephthalate (PBAT), a copolymer of p-hydroxybutyric acid and p-hydroxyvaleric acid (PHBV), and a copolymer of polybutylene succinate adipate (PBSA);(iv) optionally at least one biodegradable homopolymer selected from a homopolymer of poly (s- caprolactone), a homopolymer of polybutylene succinate, a homopolymer of polyhydroxybutyric acid, a homopolymer of polyhydroxyvaleric acid; and(v) optionally at least one additive; wherein the polylactide based copolymer and the poly(s-caprolactone) based copolymer are as defined in claim 2.

4. The non-metallic and compostable twist-tie according to any of the claims 1-3, wherein the composition comprises:(I) a poly (L-lactide) homopolymer;(II) at least one biodegradable poly(L-lactide)-co-polycaprolactone (PLA-b-PCL) block copolymer;(ill) optionally at least one additional biodegradable copolymer selected from a poly(s-caprolactone) based copolymer, a copolymer of polybutylene adipate-co-terephthalate (PBAT), a copolymer of P-hydroxybutyric acid and p-hydroxyvaleric acid (PHBV), and a copolymer of polybutylene succinate adipate (PBSA);(iv) optionally at least one biodegradable homopolymer selected from a homopolymer of poly (s- caprolactone), a homopolymer of polybutylene succinate, a homopolymer of polyhydroxybutyric acid, a homopolymer of polyhydroxyvaleric acid; and(v) optionally at least one additive; wherein the poly(s-caprolactone) based copolymer is as defined in claim 2.

5. The non-metallic and compostable twist-tie according to any of the claims 1-4, wherein the copolymer (II) is a polylactide based block copolymer wherein the percentage by weight of the first block ranges from 40 % to 90; and the percentage by weight of the second block ranged from 10% to 60%; being the sum equal to 100%.

6. The non-metallic and compostable twist-tie according to any of the claims 1-5, wherein the poly (L-lactide) homopolymer (I) has a number average molecular weight (Mn) ranging from 20000 to 500000 g / mol measured by gel permeation chromatography (GPC); the at least one biodegradable copolymer (II) has a number average molecular weight (Mn) ranging from 30000 to 300000 g / mol measured by gel permeation chromatography (GPC); the optional at least one biodegradable copolymer (ill) has a number average molecular weight (Mn) ranging from 50000 to 300000 g / mol measured by gel permeation chromatography(GPC); and the optional at least one biodegradable homopolymer (iv) has a number average molecular weight (Mn) ranging from 20000 to 500000 g / mol measured by gel permeation chromatography (GPC).

7. The non-metallic and compostable twist-tie according to any of the claims 1-6, wherein the block copolymer (II) is one of formula (I):wherein: m is an integer from 50 to 10000, preferably from 100 to 8000, more preferably from 130 to 5000, particularly preferred from 139 to 1.388; n is an integer from 30 to 6000, preferably from 50 to 3000, more preferably from 80 to 1000, particularly preferred from 88 to 876; wherein in the second block defined by square bracket with the numerical value n, X is a repeating unit selected from s-caprolactone, butylene succinate, butylene succinate adipate, hydroxybutyric acid, and hydroxyvaleric acid; wherein the first block defined by square bracket with the numerical value m, the polylactide monomer is selected from L-lactide, D-lactide and LD-lactide. wherein In is a radical derived from a proper initiator.

8. The non-metallic and compostable twist-tie according to claim 7, wherein the percentage by weight of the poly (L-lactide) homopolymer (I) ranges from 55 wt% to 97 wt%; the percentage by weight of the at least one biodegradable copolymer (II) ranges from 3 wt% to 20 wt; the percentage by weight of the at least one additional biodegradable copolymer (ill) ranges from 0 wt% to 20 wt; the percentage by weight of the at least one additional biodegradable homopolymer (iv) ranges from 0 wt% to 20 wt%; and the percentage by weight of the at least one additive (v) ranges from 0 wt% to 10 wt%; being the sum of the percentages equal to 100%.

9. The non-metallic and compostable twist-tie according to any of claims 7-8, wherein the initiator is selected from a monofunctional methoxy diethylene glycol, and an (C2-C20) alkanol.

10. A process for the preparation of the non-metallic and compostable twist-tie according to any of claims 1-9, the method comprising:(a) preparing a composition comprising:(i) a poly (L-lactide) homopolymer;(ii) at least one biodegradable copolymer;(ill) optionally at least one biodegradable homo- or copolymer other than (I) or (II); and (iv) optionally at least one additive. wherein the components (I), (II), (ill) and (iv) are as defined in any of claims 1-10;(b) shaping the composition to form the non-metallic and compostable twist-tie.11 . The process according to claim 10, wherein the shaping step (b) comprises a monofilament extrusion process, where after the extrusion process, alternate at least two consecutive series of cooling steps and stretching stage.

12. The process according to any of claims 10-11, wherein cooling steps are performed by air cooling or using a cooling bath, which comprises dipping the extruded monofilament into a liquid medium.

13. The process according to any of claims 10-12, wherein the shaping step comprises a consecutive series of a first cooling step at a temperature ranging from 20-60 °C; a first stretching step; a second cooling step at a temperature ranging from 35-50°C; and a second stretching step.

14. A non-metallic and compostable twist-tie obtainable according to the method as described in any of claims10-13.

15. Use of the non-metallic and compostable twist-tie according to any of claims 1-9 or claim 14, for sealing packages or for tying, fastening or securing products, particularly for agricultural products or electric cables.

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