EP3818099A1

EP3818099A1 - High pla content plastic material comprising a citrate ester

Info

Publication number: EP3818099A1
Application number: EP19734824.6A
Authority: EP
Inventors: Madiha ALOUI DALIBEY; Clémentine ARNAULT
Original assignee: Carbiolice SAS
Current assignee: Carbiolice SAS
Priority date: 2018-07-06
Filing date: 2019-07-05
Publication date: 2021-05-12
Also published as: US11993705B2; US20210284836A1; CN112384554A; FR3083543B1; WO2020008029A1; FR3083543A1

Abstract

The present invention relates to a plastic composition based on biodegradable and biosourced polyesters, in particular for preparing plastic films.

Description

HIGH PLA CONTENT PLASTIC COMPRISING ESTER OF

CITRATE

FIELD OF THE INVENTION

The present invention relates to a plastic composition based on biodegradable and biobased polyesters, in particular for the preparation of plastic films.

STATE OF THE ART

Biobased and biodegradable films are known, based on starches or on derivatives of starches and polyesters, in particular monolayer or multilayer films, used in particular for the manufacture of plastic bags. These bags are used in particular for packaging food products, in particular fruit and vegetables.

Mention will in particular be made of the films described in the patents and patent applications US 6,841, 597, US 5,436,078, WO 2007/1 18828, WO 2002/059202, WO 2002/059199, WO 2002/059198, US 9,096,758, WO 2004/052646 and CN 106881929. The bio-based and / or biodegradable materials used to maintain the mechanical properties suitable for their use remain expensive.

The increase in the content of PLA (polylactic acid) makes it possible to increase the content of less expensive bio-based materials, such as, for example, in biodegradable resin compositions (WO 2018/056539). This increase in the PLA content generally requires the use of a compatibilizing agent to allow the PLA to be mixed with another polyester, such as PBAT (polybutylene adipate terephthalate). Such compatibilizers are known for this use, in particular polyacrylates, such as the products marketed under the names Joncryl® ADR (Dong & al., International Journal of Molecular Sciences, 2013, 14, 20189-20203; Ojijo & al., Polymer 2015 , 80, 1 -17; EP 1 699 872; EP 2 258 775; EP 2 679 633; WO 2013/164743; WO 2015/057694; US 7 448 510; US 2012/232191; US 7 368 503)

However, the increase in the PLA content occurs at the expense of the mechanical properties of the products prepared with these polymer compositions. Thus, the films obtained with such compositions with a high PLA content and despite the addition of compatibilizing agent have reduced mechanical properties compared to films with less PLA, in particular in terms of elongation at break and of strength. tearing. In fact, increasing the PLA content in the compositions of the prior art does not make it possible to meet the specifications of the sacherie. The invention solves this technical problem by adding a particular plasticizer to the mixture of polyesters and compatibilizer.

STATEMENT OF THE INVENTION

The invention relates to a plastic composition which comprises

at. at least 20% by weight of PLA (polylactic acid),

b. at least 45% by weight of a polyester chosen from PBAT (polybutylene adipate terephthalate), PHAs (polyhydroxyalkanoates), PBS (polybutylene succinate), PBSA (polybutylene succinate adipate) and their mixtures,

vs. a PLA / Polyester compatibilizer, and

d. a plasticizer chosen from citrate esters.

The invention also relates to a plastic film, the composition of which comprises a composition according to the invention, in particular obtained by extrusion of a composition according to the invention.

The invention finally relates to a process for preparing a composition according to the invention which comprises at least the successive stages of mixing and melting with

1. PLA and compatibilizer, then

2. the polyester chosen from PBAT (polybutylene adipate terephthalate), PHAs (polyhydroxyalkanoates), PBS (polybutylene succinate), PBSA (polybutylene succinate adipate) and their mixtures,

the plasticizer chosen from citrate esters which can be added at any time during the process.

DETAILED DESCRIPTION OF THE INVENTION

The invention relates to a plastic composition which comprises

at. at least 20% by weight of PLA (polylactic acid),

b. at least 45% by weight of a polyester chosen from PBAT (polybutylene adipate terephthalate), PHAs (polyhydroxyalkanoates), PBS (polybutylene succinate), PBSA (polybutylene succinate adipate) and their mixtures

vs. a PLA / Polyester compatibilizer, and

d. a plasticizer chosen from citrate esters.

Unless otherwise indicated, the percentages are given by weight relative to the total weight of the composition to which they refer.

The constituents of the composition according to the invention are well known to those skilled in the art, in particular described in the publications, patents and patent applications mentioned above, in particular the polyesters and the PLA commonly used in the industry. biodegradable and / or biobased plastic materials, in particular for the preparation of biobased and biodegradable films.

PLA is formed from levorotatory lactic acid monomers (L) and / or dextrorotatory monomers (D), the level of monomers (L) and (D) can be variable. PLA can be a mixture of levorotatory PLA (PLLA), which is formed from predominantly monomers (L), and dextrorotatory PLA (PDLA), which is formed from predominantly monomers (D).

Advantageously, the polyester b) is PBAT. When used in admixture with other polyesters such as PHAs, PBS or PBSA, PBAT is in the majority in the blend of polyesters other than PLA, preferably more than 60% of the blend, more preferably more from 70% even more preferably more than 80% by weight. According to a particular and preferred embodiment of the invention, polyester b) other than PLA is essentially PBAT, more preferably consists of only PBAT.

The compatibilizers PLA / Polyesters are well known to those skilled in the art, in particular chosen from polyacrylates, terpolymers of ethylene, acrylic ester and glycidyl methacrylate (for example sold under the brand Lotader® by the company Arkema) , triblock copolymers PLA-PBAT-PLA, PLA grafted with maleic anhydride (PLA-g-AM) or PBAT grafted with maleic anhydride (PBAT-g-AM).

According to a preferred embodiment of the invention, the compatibilizer is chosen from polyacrylates, advantageously selected from methacrylate derivatives, preferably the compatibilizer is poly (ethylene-co-methyl acrylate-co-glycidyl methacrylate). Such compatibilizers are well known and described in particular by Dong & al. (International Journal of Molecular Sciences, 2013, 14, 20189-20203) and Ojijo & al. (Polymer 2015, 80, 1 -17). A preferred compatibilizer is poly (ethylene-co-methyl acrylate-co-glycidyl methacrylate) sold under the name JONCRYL ADR-4468- ^® by the company BASF.

Citrate esters are also plasticizers known to those skilled in the art, in particular as bio-based materials. These include triethyl citrate (TEC), triethyl acetyl citrate (TEAC), tributyl citrate (TBC), tributyl acetyl citrate (TBAC). Preferably, the citrate ester used as a plasticizer in the composition according to the invention is TBAC.

Preferably, the composition according to the invention comprises at least 25% of PLA, more preferably at least 28% of PLA, even more preferably at least 30% of PLA. The combination of the compatibilizer and the plasticizer used according to the invention and in particular the selection of citrate esters as plasticizers makes it possible to obtain PLA contents up to at least 35%, or even more, up to approximately 50% of PLA.

The polyester content b) is advantageously at least 50% of the total weight of the composition. According to an advantageous embodiment of the invention, the polyester content b) is between 60 and 72%.

The content of compatibilizer c) in the composition according to the invention is advantageously at least 0.1%, preferably from 0.4 to 2%, in particular 0.4, 0.5, or 1%, more preferably from 0.4 to 1.5%, advantageously approximately 0.4% by weight relative to the total weight of the composition.

The content of citrate ester plasticizer d) in the composition according to the invention is advantageously at least 0.5%, preferably from 1 to 5%, more preferably from 2 to 4%, advantageously from approximately 3%, preferably about 2.5%.

The composition according to the invention may comprise other usual additives used in the composition of plastics, in particular for the preparation of films, such as mineral or organic fillers, pigments or dyes, etc. In a particular example, the composition according to the invention can comprise calcium carbonate.

In a particular case, the composition according to the invention comprises, relative to the total weight of the composition

at. at least 25% by weight of PLA (polylactic acid), preferably at least 28%, more preferably at least 30% of PLA,

b. at least 60% by weight of a polyester chosen from PBAT (polybutylene adipate terephthalate), PHAs (polyhydroxyalkanoates), PBS (polybutylene succinate), PBSA (polybutylene succinate adipate) and their mixtures

vs. between 0.4 to 1.5% of a PLA / Polyester compatibilizer chosen from polyacrylates, and d. between 2 to 4% of a plasticizer chosen from citrate esters.

The composition according to the invention can also comprise enzymes capable of degrading the polyesters so as to improve the biodegradability of the film according to the invention. In a particular embodiment, the composition according to the invention can comprise enzymes capable of degrading the PLA. Such enzymes and their mode of incorporation into thermoplastic films are known to those skilled in the art, in particular described in patent applications WO 2013/093355, WO 2016/198652, WO 2016/198650, WO 2016/146540 and WO 2016/062695. Preferably, these enzymes are chosen from proteases and serine proteases. In a particular mode, the serine proteases are chosen from the Proteinase K of Tritirachium album, or the enzymes degrading the PLA originating from Amycolatopsis sp., Actinomadura keratinilytica, Laceyella sacchari LP175, Thermus sp., Or Bacillus licheniformis or commercial enzymes reformulated and known to degrade PLA such as Savinase®, Esperase®, Everlase® or any enzyme of the family of subtilisins CAS 9014-01 -1 or any functional variant.

When the composition according to the invention also comprises enzymes degrading the polyesters, in particular degrading the PLA, the composition supplemented with enzymes is advantageously as follows:

From 80% to 98% by weight, preferably from 90% to 98% by weight, of the composition rich in PLA previously defined, and

From 2 to 20%, preferably from 2% to 10%, of an enzymatic composition comprising from 0.0005 to 10% of enzyme associated with 50 to 95% of a polymer of low melting point and optionally associated with a stabilizing. This stabilizer can be chosen from polysaccharides, preferably from natural gums such as gum arabic.

Said enzymatic composition can be prepared by extruding 50 to 95%, preferably 70 to 90%, of a low melting point polymer and 5 to 50%, preferably 10 to 30%, of a formulation liquid enzyme comprising from 0.01 to 35% of enzymes, from 19 to 60% preferably 19 to 65% of water and from 15 to 70% of stabilizer.

Such enzymatic compositions and / or liquid enzymatic formulations suitable for the preparation of polymer mixtures rich in PLA are described in particular in patent applications WO 2019/043145 and WO 2019/043134.

A preferred enzymatic composition comprises in particular from 50 to 95% of a low melting point polymer, in particular polycaprolactone (PCL), preferably from 70 to 90%, from 0.001 to 10% of enzymes, preferably from 0.5 at 6%, or even 1 to 6%, and from 1.5 to 21% of gum arabic, preferably from 3 to 7%.

The supplemented enzyme composition according to the invention will advantageously comprise

- at least 20% of PLA, advantageously at least 25% of PLA

- at least 40% of PBAT

- at least 0.08% of PLA / PBAT compatibilizer, advantageously at least 0.4%

- at least 0.4% of plasticizer chosen from citrate esters

- at least 0.002% of enzyme, advantageously at least 0.05% and

- At least 1.4% of a polymer with a low melting point, advantageously at least 1.5%.

A person skilled in the art will know how to adapt the content of enzymes, and consequently the content of polymer with a low melting point and other additives provided by the enzymatic composition as a function of his objectives for the rate of degradation of PLA by enzymes. The invention also relates to a process for the preparation of compositions according to the invention, with the compounds described above, with their proportions, comprising the steps of

1. mix the PLA and the compatibilizer at a temperature where the PLA is partially or completely melted, then

2. add polyester chosen from PBAT (polybutylene adipate terephthalate), PHAs (polyhydroxyalkanoates), PBS (polybutylene succinate), PBSA (polybutylene succinate adipate) and their mixtures, at a temperature where the previously obtained mixture is partially or totally melted.

The plasticizer chosen from citrate esters can be added at any time during the process: at the time of step 1 with the PLA and the compatibilizer, between step 1 and step 2, at the time of step 2 with polyester or after step 2.

In a particular case, the invention relates to a process for preparing a composition according to the invention comprising the steps of

1. mix at least 25% by weight (relative to the total weight of the composition of the invention) of PLA and between 0.4% and 1.5% by weight of compatibilizer at a temperature greater than or equal to 120 ° C., then

2. add at least 60% of the polyester chosen from PBAT (polybutylene adipate terephthalate), PHAs (polyhydroxyalkanoates), PBS (polybutylene succinate), PBSA (polybutylene succinate adipate) and their mixtures, at a temperature where the mixture previously obtained is partially or totally melted,

adding between 2 to 4% by weight of the plasticizer chosen from citrate esters which can be carried out at any time during the process.

The preparation of the composition is carried out according to the usual methods of the technique, in particular by extrusion. The extruded molten mixture is then cooled to form granules and is generally transformed into a final article of particular shape (films, flexible or solid parts).

When the articles prepared with the composition according to the invention also comprise enzymes degrading the polyesters as defined above, the latter are added either at the time of the preparation of the composition, or at the time of the preparation of the final articles by mixing granules of composition according to the invention, and the enzymes in a form suitable for their incorporation and according to the usual methods known to those skilled in the art.

To facilitate the incorporation of the enzymes into the composition according to the invention, the latter will advantageously be used in the form of a suitable composition, which allows both the preservation and the transport of the enzymes, but also promotes their incorporation by preventing their degradation during this incorporation step. Such compositions are known to those skilled in the art, and in particular described in patent applications WO 2019/043145 and WO 2019/043134.

In particular, the addition of enzymes to the composition according to the invention can advantageously be carried out as follows: mixture between 80% and 98% of a composition according to the invention, with between 2% and 20% of a composition comprising an enzyme degrading the polyester and in particular the PLA, the percentages being given by weight relative to the weight of the final composition.

The invention also relates to any article of plastic material made up or comprising elements made up of the composition according to the invention.

According to a first embodiment, the composition is in the form of granules prepared according to the usual techniques. These granules may be stored, transported, as granules used in the manufacture of plastic products, whatever their form and use, which can be called "final articles". They can be films, or flexible or solid parts of shapes and volumes adapted to their uses.

The methods for preparing these final articles are well known to those skilled in the art, including in particular the usual techniques of plastics such as extrusion-inflation, extrusion-blowing, extrusion of cast film, calendering and thermoforming, injection molding, compression molding, rotational molding, coating, lamination, expansion, pultrusion, compression-granulation. Such operations are well known to those skilled in the art, who will easily adapt the conditions of the process as a function of the type of plastic articles provided (for example temperature, residence time, etc.).

The composition according to the invention is particularly suitable for the production of plastic films. The films according to the invention can be produced according to the usual methods of the technique, in particular by extrusion-inflation. The films can be prepared directly at the outlet of the extrusion die used for the preparation of the composition according to the invention, or also from granules of composition according to the invention which are melted according to the usual techniques, in particular by extrusion.

The invention therefore also relates to a film of composition as defined above, with or without enzymes. The films according to the invention can be monolayer or multilayer films. In the case of a multilayer film, at least one of the layers has a composition as defined above.

The composition according to the invention is particularly suitable for being combined with enzymes degrading polyesters for the production of biodegradable plastic films. Plastic films, in particular monolayer films, of composition as defined above, have both a high PLA content and retain mechanical properties as sought for the preparation of biodegradable and bio-based bags, in particular for packaging, films mulching, packaging of non-food or food products.

To this end, the constituents of the composition according to the invention will preferably be chosen from products compatible with food use.

The films according to the invention advantageously have a thickness of less than 100 μm, more advantageously less than 50 μm, 40 μm or 30 μm, preferably less than 20 μm, in particular from 10 to 20 μm, more preferably from 6 to 20 μm.

The plastic films obtained with the composition according to the invention advantageously have the following properties,

- an elongation at break greater than 130% in the longitudinal direction and greater than 240% in the transverse direction, measured according to standard EN ISO 527-3, and / or

- a tear resistance greater than 30 N / mm in the transverse direction of the film, measured according to standard EN ISO 6383-1

and this while having a high content of PLA.

The elongation at break of the plastic film obtained with the composition according to the invention is advantageously at least 170%, in the longitudinal direction preferably at least 200%.

The tear resistance of the plastic film obtained with the composition according to the invention is advantageously at least 35 N / mm in the transverse direction of the film, preferably at least 40 N / mm, more preferably at least 45 N / mm

In a particular embodiment, the plastic films obtained with the composition according to the invention also have the following properties,

1. an elastic modulus greater than 200 MPa in the longitudinal direction and greater than 150 MPa in the transverse direction, measured according to standard EN ISO 527-3 and / or

2. a maximum stress greater than 15 MPa in the longitudinal direction and greater than 13 MPa in the transverse direction, measured according to standard EN ISO 527-3

The composition according to the invention can also be used for the production of rigid plastic products such as food packaging.

EXAMPLES

Example 1:

A) Production of the compositions

The compositions were produced on a Leistritz ZSE 18MAXX co-rotating twin-screw extruder. Solid materials such as polymers and compatibilizer were introduced using one or two gravimetric dosers depending on the composition. Indeed, for the compositions comprising the compatibilizer Joncryl® ADR 4468 C, first the PLA and compatibilizer mixture was introduced at the start of the extruder via a first dispenser, then the PBAT was introduced in a delayed manner via a second dispenser. For the compositions without compatibilizer, the PLA (4043D) and the PBAT (Ecoflex® C1200) were mixed and then introduced with a dispenser from the start of the extrusion. TBAC (Citrofol® BII) was introduced with a Brabender liquid pump from the start of extrusion. CaC03 was introduced with a gravimetric doser in zone 7/10.

All the compositions were prepared under the same process conditions with a screw speed of 70 rpm and at a flow rate of 2 to 4 kg / h.

The parameters used for the extrusion of the compositions are presented in Table 1.

Table 1

The mixture of components arrives in the molten state in the last zone of the twin-screw which comprises a die with a hole with a diameter of 3.5 mm and is immediately immersed in a 2 m water tank and brought to a granulator to obtain cylindrical granules with a diameter of less than 3 mm.

The granules obtained have the compositions described in table 2 (% by weight relative to the total weight of the composition)

Table 2

B) Production of films with the compositions described in A)

Compositions 1 to 6 prepared in A) were used for the preparation of films. For the inflation extrusion, a LabTech LF-250 laboratory line, 20 mm wide, 30 L / D screw type LBE20-30 / C was used. Before the swelling extrusion, the compositions were dried in a desiccator for 4 hours at 80 ° C. The screw speed was 60 rpm. The inflation rate was around 5.

The inflation extrusion temperature settings are detailed in Table 3.

Table 3

The average thicknesses of the films produced, measured with a micrometer, are given in Table 4.

Table 4

C) Characterization of the mechanical properties in simple traction and in tearing

The films were then mechanically characterized in simple traction and in tearing using a Zwick test machine equipped with a 50 N sensor. The experimental conditions by type of test are summarized in Table 5.

A “pants” type test piece is used for the tear test.

Two important criteria in the field of bag making are elongation at break and resistance to tearing. The tear is only characterized in the transverse direction of the film.

Table 5

The results obtained for Films 1 to 6 are given in Table 6 (MD = Longitudinal Direction; TD = Transversal Direction)

Table 6

The inventors established a specification to allow the films of the invention to be sold in the sack market, namely that it is desirable that the films of the invention reach the following values:

Elongation at break, which measures the ability of a material to lie under load before it breaks: 130% in the longitudinal direction and 240% in the transverse direction measured according to EN ISO 527-3.

Tear resistance: 40 N / mm in the transverse direction and measured according to the conditions of standard DIN EN ISO 6383 at 200 mm / min or under the conditions as described in this example.

By comparing the properties of Films 1, 2 and 3, it is observed that the composition described in the invention makes it possible to achieve the properties of the specifications. Indeed, the presence of the compatibilizer Joncryl® (Film 1) or the plasticizer TBAC (Film 2) alone does not allow it.

The comparison of Film 4 (20% PLA), with Film 5 (25% PLA) and with Film 3 (30% PLA) shows that the reduction in the PLA level makes it possible to improve the discriminating properties of the film. . Hence the interest of the invention in increasing the level of PLA in films while retaining the properties of the specifications.

By comparing Films 6 and 7 with Films 4 and 5 respectively, it is shown that the addition of CaCO 3 fillers causes a slight reduction in elongation properties while remaining within the specifications. The films of the invention must also meet criteria of elastic modulus and maximum stress. The characteristics of elastic modulus and maximum stress of the films are given in table 7.

Table 7

The specifications drawn up by the inventors and adapted to the bag making market demand that the films reach the following values:

Elastic modulus: 200 MPa in the longitudinal direction and 150 MPa in the transverse direction Maximum stress: 15 MPa in the longitudinal direction and 13 MPa in the transverse direction

All the films resulting from the invention have properties of elastic modulus and maximum stress not deteriorated compared to the films of the state of the art, and corresponding to the values requested by the specifications defined above.

Example 2:

A) Production of the composition

The granules were produced on a Clextral Evolum 25 HT co-rotating twin-screw. To introduce the polymers (PLA 4043D and PBAT Ecoflex® C1200) and the compatibilizer two gravimetric dosers were used and to dose the liquid TBAC, a PCM pump was used.

The PLA and Joncryl® mixture was introduced via a metering device at the start of the screw in the presence of the plasticizer TBAC. The mixture is melted and brought to the PBAT introduction area.

The granules were prepared with a screw speed of 500 rpm and at a flow rate of 40 kg / h. The parameters used for the extrusion of the granules are presented in the table

8.

Table 8 The mixture of components arrives in the molten state in the Z12 screw and is immediately immersed in a 2.5 m water tank and brought to a granulator to obtain cylindrical granules with a diameter of less than 3 mm.

Three compositions are prepared, a composition 8 corresponding to the state of the art comprising 30% of PLA and 70% of PBAT, a composition 9 according to the invention comprising 30% of PLA, 66% of PBAT, 3% of T BAC and 1% of Joncryl® ADR 4468 C, and a composition 10 according to the invention comprising 35% of PLA, 60.3% of PBAT, 3.5% of TBAC and 1.2% of Joncryl® ADR 4468 C (% by weight relative to the total weight of the composition).

B) Production of the film with the compositions described in A)

The granules prepared as described in A) were used for swelling extrusion with the same process and the same parameters described in example 1 part B).

The film 8 of composition 8 has an average thickness of 10 μm. Films 9 and 10 of compositions 9 and 10 have an average thickness of 14 μm. The thicknesses were measured with a micrometer.

The films were then mechanically characterized in simple traction and in tear using a Lloyd LS5 testing machine equipped with a 20 N sensor and using the standards EN ISO 527-3 and EN ISO 6383-1. respectively. The experimental conditions by type of test are summarized in Table 9.

A “pants” type test piece is used for the tear test.

Table 9

The elongation at break and tear characteristics of the composition are given in Table 10. Table 10

The characteristics of elastic modulus and maximum stress of the films are given in table 11.

Table 11

Films 9 and 10 according to the invention meet all the properties of the specifications defined by the inventors in example 1 part C), unlike film 8.

Example 3 - Comparison using another plasticizer

A composition 1 1 based on dibutyl sebacate (DBS) produced with the same compounding and extrusion-swelling processes as in Example 1 was produced for comparison. Composition 9 comprises 29% PLA, 67% PBAT, 3% DBS and 1% Joncryl® ADR 4468C.

The film 1 1 corresponding to the composition 1 1 was characterized under the same conditions as the films of example 1 part D).

Its elongation at break and tear characteristics are given in table 12. Table 12

Unlike the plasticizer selected for the composition according to the invention, the use of a conventional plasticizer such as DBS does not make it possible to meet all of the specifications defined by the inventors and adapted to the bag making market, the elongation at break in the transverse direction being less than 240% required and its breaking strength being less than 40 N / mm required.

Example 4:

A) Production of the compositions

The granules were produced on a Clextral Evolum 25 HT co-rotating twin-screw. To introduce the polymers (PLA and PBAT) and the compatibilizer two gravimetric dosers were used and to dose the liquid TBAC, a PCM pump was used.

The granules were prepared with a screw speed of 450 rpm and at a flow rate of 40 kg / h.

The parameters used for the extrusion of the granules are presented in Table 13.

Table 13

The mixture of components arrives in the molten state in the screw in Z1 1 and is immediately granulated with an underwater cutting system to obtain half-moon granules with a diameter of less than 3 mm.

3 compositions are prepared, a composition 12 according to the invention comprising 35% of PLA, 61, 1% of PBAT, 3.5% of TBAC and 0.4% of Joncryl® ADR 4468, a composition 13 according to the invention comprising 35% of PLA, 62.1% of PBAT, 2.5% of TBAC and 0.4% of Joncryl® ADR 4468, and a composition 14 according to the invention comprising 35% of PLA, 59.6% of PBAT, 2.5% TBAC 2.5% CaCO3 and 0.4% Joncryl® ADR 4468 (% by weight relative to the total weight of the composition). B) Production of the film with the compositions described in A)

The granules prepared as described in A) were used for swelling extrusion with the same process and the same parameters described in example 1 part B). The film 12 of composition 12 has an average thickness of 13.7 μm. Films 13 and 14 of compositions 13 and 14 have an average thickness of 15 μm. The thicknesses were measured with a micrometer.

The films were then mechanically characterized in simple traction and in tear using a Lloyd LS5 testing machine equipped with a 20 N sensor and using the standards EN ISO 527-3 and EN ISO 6383-1. respectively. The experimental conditions by type of test are summarized in Table 9 of Example 2.

A “pants” type test piece is used for the tear test.

The elongation at break and tear characteristics of the composition are given in Table 17.

Table 17

The characteristics of elastic modulus and maximum stress of the films are given in table 14.

Table 14

Films 12, 13 and 14 according to the invention meet all of the properties of the specifications defined by the inventors. The addition of CaC03 slightly decreases the mechanical properties (elongation at break in the longitudinal direction and stress at break in both directions of measurement) while remaining within the specifications.

Example 5:

A) Production of the composition

The parameters used for the extrusion of the granules are presented in Table 15.

Table 15

The mixture of components arrives in the molten state in the Z11 screw and is immediately granulated with an underwater cutting system to obtain half-moon granules with a diameter of less than 3 mm.

A composition 15 is prepared according to the invention comprising 35% of PLA, 62.1% of PBAT, 2.5% of TBAC and 0.4% of Joncryl® ADR 4468

B) Production of the film with the composition described in A)

The granules prepared as described in A) were used for the calendering film extrusion. For calendering extrusion, a FAIREX extruder with a diameter of 45 mm, a flat die of 220 mm and adjustable lips fixed at 0.6 mm of opening were used as well as a three-cylinder calendering machine. Before extrusion, the composition was dried for 4 hours at 80 ° C. in a desiccator.

The extrusion and calendering settings are detailed in Table 26. Table 16

The calendered film 15 of composition 15 has an average thickness of 30 µm. The thicknesses were measured with a micrometer.

The film was then mechanically characterized in simple traction and in tear using a Lloyd LS5 testing machine equipped with a 5 kN sensor and using the standards EN ISO 527-3 and EN ISO 6383-1. respectively. The experimental conditions by type of test are summarized in Table 9 of Example 2.

A “pants” type test piece is used for the tear test.

Table 17

The characteristics of elastic modulus and maximum stress of the film are given in table 18.

Table 22

The inventors have established specifications to allow the film of the invention to be sold in the packaging market, namely that it is desirable for the film of the invention to reach the following values:

Elongation at break, which measures the capacity of a material to lie under load before it breaks: 10% in the longitudinal direction and measured according to standard EN ISO 527-3.

Tear resistance: 8 N / mm in the longitudinal direction and measured according to the conditions of DIN EN ISO 6383 at 200 mm / min or under the conditions as described in this example.

The elastic module: 400 MPa in the longitudinal direction

Maximum stress: 1 1 MPa in the longitudinal direction

The film 15 according to the invention meets all of the properties of the specifications defined by the inventors. This film has even more favorable properties, especially and especially in terms of elongation.

REFERENCES

Dong & al., International Journal of Molecular Sciences, 2013, 14, 20189-20203

Ojijo & al., Polymer 2015, 80, 1-17

CN 106881929

EP 1,699,872; EP 2,258,775; EP 2,679,633

US 6,841,597, US 5,436,078, US 9,096,758, US 7,448,510, US 2012/232191, US 7,368,503 WO 2002/059202, WO 2002/059199, WO 2007/1 18828, WO 2002/059198, WO

2004/052646; WO 2013/164743; WO 2015/057694; WO 2019/043145 WO 2013/093355, WO 2016/198652, WO 2016/198650, WO 2016/146540, WO 2016/062695, WO

2019/043134

Claims

Claims 1 A plastic composition which comprises a. at least 20% by weight of PLA (polylactic acid), b. at least 45% by weight of a polyester chosen from PBAT (polybutylene adipate terephthalate), PHAs (polyhydroxyalkanoates), PBS (polybutylene succinate), PBSA (polybutylene succinate adipate) and their mixtures, c. a PLA / Polyester compatibilizer, and d. at least 0.5% by weight of a plasticizer chosen from citrate esters. 2 Composition according to claim 1, characterized in that the polyester b) is PBAT. 3 Composition according to one of claims 1 or 2, characterized in that the compatibilizer is chosen from polyacrylates. 4 Composition according to claim 3, characterized in that the compatibilizer is selected from methacrylate derivatives. 5 Composition according to claim 4, characterized in that the compatibilizer is poly (ethylene-co-methyl acrylate-co-glycidyl methacrylate). 6 Composition according to one of claims 1 to 5, characterized in that the citrate esters are chosen from triethyl citrate (TEC), triethyl acetyl citrate (TEAC), tributyl citrate (TBC), tributyl acetyl citrate ( TBAC). 7 Composition according to claim 6, characterized in that the citrate ester is TBAC. 8 Composition according to one of claims 1 to 7, characterized in that the composition according to the invention comprises at least 25% of PLA. 9 Composition according to one of claims 1 to 8, characterized in that the polyester content b) is at least 50% of the total weight of the composition. 10 Composition according to one of claims 1 to 9, characterized in that the content of compatibilizer c) is 0.4 to 2% by weight relative to the total weight of the composition. 1 1 Composition according to one of claims 1 to 10, characterized in that the plasticizer content of citrate esters d) is from 1 to 5% by weight relative to the total weight of the composition. 12 Composition according to one of claims 1 to 1 1, characterized in that it further comprises enzymes degrading the polyesters. 13 plastic film, in particular monolayer film, of composition as defined according to one of claims 1 to 11. 14 process for preparing compositions according to one of claims 1 to 1 1, characterized in that it comprises the steps of

1. mix the PLA a) and the compatibilizer c) chosen from polyacrylates at a temperature where the PLA is partially or completely melted, then

2. add polyester b) chosen from PBAT (polybutylene adipate terephthalate), the

PHAs (polyhydroxyalkanoates), PBS (polybutylene succinate), PBSA (polybutylene succinate adipate) and their mixtures at a temperature where the previously obtained mixture is partially or completely melted,

the plasticizer d) chosen from citrate esters which can be added at any time during the process.