EP2705083A1

EP2705083A1 - Novel durable, hydrolysis-stable bio-based plastics based on polyhydroxyalkanoate (pha), method for producing same, and use thereof

Info

Publication number: EP2705083A1
Application number: EP12718215.2A
Authority: EP
Inventors: Andrea Fruth; Andreas Krug; Bernd Wiloth
Original assignee: Rhein Chemie Rheinau GmbH
Current assignee: Rhein Chemie Rheinau GmbH
Priority date: 2011-05-06
Filing date: 2012-05-02
Publication date: 2014-03-12
Also published as: CN103517941A; US20140155557A1; WO2012152625A1; JP2014514418A; CA2835251A1

Abstract

The invention relates to novel durable, hydrolysis-stable bio-based plastics based on polyhydroxyalkanoate (PHA), the melt of said plastics being adequately stable, to a method for the producing same, and to the use thereof.

Description

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Novel long-life, hydrolysis-stable bio-based plastics based on polyvinyl alcoholate (PHA), a process for their preparation and their use

The invention relates to novel, long-lasting, hydrolysis-stable, bio-based plastics based on polyhydroxyalkanoate (PHA), which have sufficient melt stability, a process for their preparation and their use.

Bio-based plastics, known as biopolymers, are ecologically more sustainable materials compared to petrochemical-based plastics because of the bio-based raw materials used. In particular with regard to environmental protection and the threat of global warming, bio-based plastics have gained increasing importance not only in the packaging sector but also in the production of durable and technical plastic products. However, in order to make bio-based materials based on polyhydroxyalkanoates competitive in comparison to conventional and established materials, optimizations in material production and processing are often necessary.

Bio-based plastics consist for example of an aliphatic polyester resin, which is produced by direct fermentative production of starch, sugar, carbohydrates, vegetable oil or fats.

Bio-based plastics have the great advantage that they are very environmentally friendly. In the field of technical applications, the group of biopolymers in particular polyhydroxyalkanoates (PHA) have the advantage that, for example, they have a higher heat resistance, compared to polylactic acid (PLA) possess. This allows the production of durable articles which are not applicable to polylactic acid due to the low softening point, e.g. Kettle, hair dryer. Furthermore, polyhydroxyalkanoates show a very low shrinkage in manufactured products, so that product geometries are possible, which can not be realized with conventional polymers.

Both polylactic acid and polyhydroxyalkanoates are classed as aliphatic polyesters and are both susceptible to polymer degradation during processing and during use. The degradation mechanism of polylactic acid proceeds via the classical route of ester hydrolysis, which, under the action of acids or bases in the presence of water, leads to cleavage of the ester bond in the polylactic acid, generating new hydroxyl and carboxyl groups. -COO- + H ₂ 0 -COOH + HO-

The new carboxyl groups lead to hydrolysis of further ester groups in the polylactic acid polymer, i. the process is autocatalytic. The ester cleavage in the polylactic acid thus leads to a polymer degradation and thus to a reduction in the life of the polylactic acid and an unstable process.

However, the product class of polyhydroxyalkanoates is much less sensitive to hydrolysis compared to polylactic acid. This difference in susceptibility to hydrolysis arises from the different degradation mechanism. In contrast to polylactic acid, polyhydroxyalkanoates are dominated by a different mechanism of β-elimination. This β-elimination leads to cleavage of the polyhydroxyalkanoate polymer chain to form unsaturated polymer fragments, see Yoshihiro Aoyagi, et al., Polymer Degradation and Stability 76, 2002, 53-59.

Compared to polylactic acid, hydrolytic degradation of polyhydroxyalkanoates plays a subordinate role but, since PHAs are also aliphatic polyesters, they may also occur. Despite the deviating degradation mechanism, polyhydroxyalkanoates have the disadvantage that they do not have sufficient hydrolytic stability for long-lived and industrial applications and are also difficult to process, which is reflected in a sharp increase in the melt volume rate (MVR). It is therefore necessary to look for a way to achieve stabilization of PHA during processing as well as during use, despite the combination of the largely predominant β-elimination and the still-occurring hydrolysis.

An attempt was made to solve this problem by adding a variety of additives. Thus, for example, in the abstract of JP-A 2008 303 286 the use of 0.5 wt.% Of a polymeric Carbodiimides described in polyhydroxyalkanoates. However, in terms of hydrolytic stability, no satisfactory result is achieved here. The same applies to WO 2009119512, in which the use of a polycarbodiimides of mixtures of polybutylene succinate and blends of polybutylene succinate with polylactic acid and polyhydroxyalkanoates is called. The aliphatic polycarbodiimide used is used for the stabilization of the polybutylene succinate. However, even here, sufficient hydrolysis resistance is not obtained.

EP-A 1 627 894 describes the use of diisopropylphenylcarbodiimide as a hydrolysis protection agent in aliphatic polyester resins. However, no satisfactory result is achieved in terms of processibility and anti-hydrolysis.

EP-A 10172530 describes the use of a combination of a monomeric and oligomeric carbodiimide. Although this leads to an improvement of the hydrolysis protection and the processing, however, this result with regard to the hydrolysis protection effect in many concentration ranges, is not sufficient.

Surprisingly, it has now been found that the bio-based plastics according to the invention from the class of polyhydroxyalkanoates containing at least> 0.5% by weight of oligomeric and / or polymeric aromatic and / or araliphatic oligomeric carbodiimide compound, perform this task.

The present invention therefore relates to biobased plastics containing a combination of at least one polyhydroxyalkanoate and at least 0.5% by weight, preferably 0.7 and 4% by weight, more preferably 1 to 2.5% by weight, very particularly preferably 1 to 2.0% by weight of at least one oligomeric and / or polymeric aromatic and / or araliphatic carbodiimide, in one preferred embodiment of the invention consisting essentially of polyhydroxyalkanoate and carbodiimide.

Other additives are e.g. Stabilizers, such as antioxidants, plasticizers, impact modifiers, flame retardants and fillers.

In the context of the invention, the biobased plastics are preferably polyhydroxyalkanoates which can be prepared by direct fermentative preparation from starch, sugar, carbohydrates, vegetable oil or fats. Polyhydroxyalkanoates are preferably compounds of structural formula (I)

with n> 10 and R ⁴ = Ci to Ci ₄ alkyl. Particularly preferred are polyhydroxybutyrate (PHB), polyhydroxyvalerate (PHV), polyhydroxybutyrate valerate (PHBV), polyhydroxyhexonate (PHH), polyhydroxyoctanoate (PHO), polyhydroxybutyratehexanoate (PHBH) and mixtures thereof.

The polyhydroxyalkanoates particularly preferred as bio-based plastics are commercially available, e.g. under the name Mirel in the Finna Teiles or as Enmat of the Tianan company, or can be prepared according to the methods familiar to the person skilled in the art, e.g. by fermentation.

As oligomeric and / or polymeric carbodiimides, all known carbodiimides of the formula (II) can be used

R '- (- N = C = NR "' -) _m -R" (II),

in the

R '"is an aromatic and / or araliphatic radical and m> 1, R'" is the same or different within the molecule and can be combined with each other in any combination of any of the aforementioned radicals,

R '"in the case of an aromatic or an araliphatic radical may bear no or at least one ortho to the aromatic carbon atom bearing the carbodiimide group, aliphatic and / or cycloaliphatic substituents having at least 2 carbon atoms, preferably branched or cyclic aliphatic radicals having at least 3 carbon atoms, in particular isopropyl groups, which may also carry heteroatoms, such as N, S and / or O, or imidazolyl, R '= Ci - Ci ₈ alkyl, C ₅ -C ₁₈ cycloalkyl, aryl, C ₇ -C ₈ -aralkyl, -R-NHCOS-R ¹ ,

-R-COO R ¹ , -R-O R ¹ , -R-NiR ¹ ^, -R-SR ¹ , -R-OH, -R-NH ₂ , -R-NHR ¹ ,

-R-epoxy, -R-NCO, -R-NHCONHR ¹ , -R-NHCONR ¹ R ² or -R-NHCOOR ³ , wherein

R = aromatic, aliphatic, cycloaliphatic and / or araliphatic radical, R "= H, -N = C = N-aryl, -N = C = N-alkyl, -N = C = N-cycloalkyl, -N = C = N-aralkyl, -NCO, -NHCONHR ¹ , -NHCONR'R ² , -NHCOOR ³ , -NHCOS-R ¹ , -COO R ¹ , -OR ¹ , -N (R ¹ ^,

-SR ¹ , -OH, -NH ₂ , -NH R ¹ , wherein in R 'and R "independently R ^l and R ^{2 are} identical or different and a Ci-C ₂ o-alkyl, C ₃ -C ₂ o-cycloalkyl, -aryl, C ₇ -C ₈ -aryl, 01igo- / polyethylene and / or -Propylenglykole represent and R ^{3 has} one of the meanings of R ¹ or a polyester or a polyamide radical, and m a whole Corresponds to from 2 to 5,000, and in the case of oligomeric carbodiimides m corresponds to an integer from 2 to 5, and in polymeric carbodiimides m corresponds to an integer of> 5, and / or of the formula (III)

R '- [- (- N = C = NY-) _p - (- B -) _q -] ₀ -X (III), with

Y = arylene, C ₇ -Cig-aralkylene

p = an integer from 1 to 500, preferably 1 to 100,

B = -NH-CO-NH-Z-, -NH-COO-Z-, -NH-COS-Z-,

q = an integer from 1 to 500, preferably 1 to 100,

o = an integer from 1 to 500, preferably 1 to 100, wherein

either p or o must be> 1.

X is H, -OH, -SH, -NH ₂ , -OR ¹ , -N (R ¹ ) ₂ , -SR ¹ , -NHR ¹ , R ² , -OCO-NH-R ', NH CO-, -NH-R ^' , -S-CO-NH-R'

R '= C 1 -C ₁₈ -alkyl, C ₅ -C ₈ -cycloalkyl, aryl, C ₇ -C ₁₈ -aralkyl, -R "' - NH-COS-R ¹ , -R 1 -COOR ¹ , -R 1 - OR ¹ , -R '"- ^ ¹ ^, - R"' -SR ¹ , -R "'--OH, -R"' - NH ₂ , -R ^ -NHR ¹ , -R "'- epoxy, R "'- NCO, - R"' - NHCONHR ¹ , - R "'- NHCONR ¹ R ² or - R"' - NH - COOR ³ , wherein

R ¹ and R ^{2 are the} same or different and are a C ₁ -C ₂₀ -alkyl, C ₃ -C ₂₀ -cycloalkyl, aryl, C ₇ -C 8 -aryl, 01igo- / polyethylene and / or propylene glycols and R ^{3 is} a has the meanings of R ¹ or denotes a polyester or a polyamide radical,

Z = Y, polyesters, polyethers, polyamides and R '"means an aromatic and / or araliphatic radical

For the purposes of the invention, the term araliphatic means an alkyl group such as - (CH ₂ ) _r , -C (CH ₃ ) ₂ -, -CH (CC ₁₈ alkyl), preferably -CH ₂ -, -C ₂ H ₄ -, -C ₃ H ₆ -, -C (CH ₃ ) ₂ -, linked, optionally substituted aromatic radical with i = 1-10 understood. Aromatic oligomeric and / or polymeric carbodiimides of the abovementioned formula (I) with m> 2 are particularly preferred.

It is likewise preferred that the polymeric and / or oligomeric carbodiimide are compounds of the formula (II) in which R 1, 3-substituted-2,4,6-triisopropylphenyl and / or 1,3-bis (l-methyl-1-isocyanatoethyl) benzene and / or tetramethylxylylene derivatives and / or 2,4-substituted tolylene and / or 2,6-substituted tolylene and / or mixtures of 2,4- or 2,6- The abovementioned carbodiimides are commercially available compounds which, for example, are available from Rhein Chemie Rheinau GmbH under the trade names Stabaxol® P (NCN content: 12.5-13.5%), Stabaxol® P 100 (NCN Content: 12.5-13.5%) and Stabaxol® P 400 (NCN content: 12.5-13.5%) are commercially available, as well as the preparation of the carbodiimides according to, for example, Angewandte Chemie 74 (21), 1962, p. 801-806 or by the condensation of diisocyanates with elimination of carbon dioxide at elevated temperatures, for example be i 40 ° C to 200 ° C, in the presence of catalysts. Suitable processes are described in DE-B-11 56 401 and in DE-B-11 305 94. As catalysts, for example, strong bases or phosphorus compounds have been proven. Preferably, phospholene oxides, phospholidines or phospholine oxides and the corresponding sulfides are used. Further, as catalysts, tertiary amines, basic metal compounds, carboxylic acid metal salts and non-basic organometallic compounds can be used. To prepare the carbodiimides and / or polycarbodiimides all isocyanates such as 2,6-diisopropylphenyl isocyanate are suitable, with preferred in the context of the present invention, carbodiimides and / or polycarbodiimides are used, which are based on substituted aromatic by Cr to _C4 alkyl isocyanates, , 2,4,6-triisopropylphenyl-l, 3-diisocyanate, 2,4,6-triethylphenyl-l, 3-diisocyanate, 2,4,6-trimethyl-phenyl-l, 3-diisocyanate, 2,4'- Diisocyanatodiphenylmethane, 3,3 ', 5,5'-tetraisopropyl-4,4'-diisocyanatodiphenylmethane, 3,3', 5,5'-tetraethyl-4,4'-diisocyanatodiphenylmethane, tetramethylxylene diisocyanate, 1, 5-naphthalene diisocyanate, 4,4'-diphenylmethane diisocyanate, 4,4'-diphenyldimethylmethane diisocyanate, 1,3-phenylenediisocyanate, 1,4-phenylenediisocyanate, 2,4-tolylenediisocyanate, 2,6-tolylenediisocyanate, a mixture of 2,4-tolylenediisocyanate and 2 , 6-tolylene diisocyanate, xylylene diisocyanate, tetramethylxylylene diisocyanate, 2,6-diisopropylphenylene isocyanate and 1,3,5-triiso propylbenzene-2,4-diisocyanate or mixtures thereof, or based on substituted aralkylene such as 1,3-bis (1-methyl-1-isocyanatoethyl) benzene. It is particularly preferred if the carbodiimides and / or Polycarbodiimides based on 2,4,6-triisopropylphenyl-l, 3-diisocyanate and / or 2,6-diisopropyl-phenylene isocyanate and / or tetramethylxylylene diisocyanate.

Polycarbodiimides, when made from isocyanates, may also contain reactive NCO groups and complexed monomeric isocyanates.

In a further preferred embodiment of the present invention, the total amount of carbodiimides, based on the plastic, is greater than 0.5%, particularly preferably> 0.7% by weight.

Furthermore, it is preferred that the proportion of polyhydroxyalkanoate in the bio-based plastic is 5-99.5%, more preferably 20-99.3%.

The present invention furthermore relates to a process for the preparation of the bio-based plastics according to the invention, according to which at least one polyhydroxyalkanoate with at least 0.5 wt.%, Preferably 0.7 to 4 wt.%, Particularly preferably 1 to 2.5 wt particularly preferably 1 to 2.0% by weight of at least one oligomeric and / or polymeric, aromatic and / or araliphatic carbodiimide are mixed in a mixing unit. Mixing units in the context of the invention are, for example, an extruder or kneader.

The subject of the present invention is also the use of the bio-based plastics according to the invention in long-lived applications, such as e.g. Electronics, automotive, construction, transportation, household, e.g. as bath utensils, or as office supplies, or for applications under severe conditions, such as sterile conditions in medicine.

The scope of the invention covers all of the above-mentioned general or preferred radical definitions, indices, parameters and explanations with one another, ie also between the respective ranges and preferred ranges in any desired combination.

The following examples serve to illustrate the invention without being limiting. EXAMPLES

Used chemicals:

CDI I: a sterically hindered, aromatic carbodiimide (Stabaxol® I LF) with an NCN content of at least 10.0%, from Rhein Chemie Rheinau GmbH.

CDI II: a sterically hindered, aromatic oligomeric carbodiimide (Stabaxol® P) with an NCN content of 13.5%, from Rhein Chemie Rheinau GmbH.

CDI III: a sterically hindered, aromatic polymeric carbodiimide (Stabaxol® P 400) with an NCN content of 13.5%, from Rhein Chemie Rheinau GmbH.

Carbodilite® LA-1 (H12MDI-PCDI): a polymeric aliphatic carbodiimide with an NCN content of 15.8%, from Nisshinbo.

Polyhydroxyalkanoate (PHA): Mirel P 1003

Polylactic acid (PLA): Ingeo 2002 D from the company Nature Works

Used devices:

The incorporation of the carbodiimides into the polyhydroxyalkanoate was carried out by means of a laboratory twin-screw extruder ZSK 25 from Finna Werner and Pfleiderer.

The amounts of additive used and the type of additive used are shown in Tables 1 to 4.

The F3 standard test specimens were produced on an Arburg Allrounder 320 S 150 - 500 injection molding machine.

For the hydrolysis test of polyhydroxyalkanoate (PHA), the F3 standard specimens were stored in water at a temperature of 85 ° C, and after various time units, a tensile test was carried out to check the tensile strength. The hydrolysis protection period describes the life of the test specimens after how many days under test conditions the tensile strength has assumed a value less than 5 MPa. For the hydrolysis tests of the comparative tests with polylactic acid (PLA), the F3 standard test specimens were stored in water at a temperature of 65 ° C and after different time units a tensile test was carried out to check the tensile strength.

The melt volume rate (MVR) was measured using a device from Göttfert, model MI 4. The residual moisture content of the polymer granules is at most 100 ppm. Test conditions for PHA (Samples 1-16): Measurement temperature 175 ° C, test weight 2.16 kg. Melting time: 5 minutes.

Test conditions for PLA (Samples 17 - 24): Measurement temperature 200 ° C, test weight 2, 16 kg, melting time: 5 minutes.

Table 1: Inventive samples and their test results (amounts in% by weight):

Sample Additives Used in PHA Hydrolysis Protection Time MVR [cc / 10 min]

[D]

1 1.0% CDi n 14 9.4

2 1.5% CDI II 29 10.8

3 2.0% CDI II 31 12.5

4 1.0% CDI III 18 9.5

5 1.5% CDI III, 30 10.7

6 2.0% CDI III, 33 11.1

Table 2: Comparative example of non-additized PHA:

Sample base mixture of hydrolysis protection duration [d] MVR [ccm / 10 min]

7 PHA directly from the container 6 7.4

8 PHA 1 x extruded 6 24.9

Table 3: Comparative Examples (amounts in% by weight):

Sample Additive in PHA Hydrolysis Protection Time [d] MVR [ccm / 10 min]

9 0.5% CDI I 6 12.9

10 1.0% CDU 14 10.8

11 1.5% CDU 19 13.5

12 2.0% CDI I 29 15.4

13 0.5% CDI II 7 10.4

14 0.5% CDI III 6 11.2

15 0.5% H12MDI-PCDI 7 22.7

16 1.0% H12MDI-PCDI 11 10.9

Table 4: Comparative Examples (amounts in% by weight):

Additives used in PLA hydrolysis protection time [d] MVR [ccnV 10 min]

17 0.5% CDI I 5 4.2

18 1.0% CDU 16 4.5 19 1.5% CDU 37 4.6

20 0.5% CDI II 6 2.9

21 1.0% CDI II 8 3.1

22 1.5% CDI II 11 3.2

TABLE 5 Comparative Example of Non-Additized PLA

Grand mix of hydrolysis protection time [d] MVR [ccm / 10 min]

23 PLA directly out of the container 5 3.4

24 PLA 1 x extraded 5 4.2

The mixtures 1 to 6 according to the invention are distinguished by high hydrolysis protection and excellent MVR values. Thus, they are significantly improved over the mixtures of PLA with carbodiimides, in which only either the hydrolytic stability or the MVR value is improved, but never both. It is also apparent from Comparative Examples 17-22 that the effects of carbodiimides in PLA and PHA are surprisingly distinctly different. In PLA, monomeric carbodiimides (CDl I) show the best hydrolysis protection time, whereas polymeric carbodiimides (CDl II) are less effective in PLA. In PHA, on the other hand, polymeric carbodiimides (CDI II and CDI III) show better hydrolysis protection than monomeric carbodiimides (CDU).

Claims

Biobased plastics containing a combination of at least one polyhydroxyalkanoate and> 0.5% by weight of at least one oligomeric and / or polymeric aromatic and / or araliphatic carbodiimide.

Biobased plastics according to claim 1, characterized in that the proportion of oligomeric and / or polymeric carbodiimides is at least 0.7 to 4 wt.%.

Biobased plastics according to claim 1 or 2, characterized in that the polymeric and / or oligomeric aromatic and / or araliphatic carbodiimide is a compound of the general formula (II)

R '- (- N = ON-R "' -) _m -R" (II),

in the

R '"is an aromatic and / or araliphatic radical and m> 1, R"' is the same or different within the molecule and can be combined with each other in any combination of any of the aforementioned radicals,

R '"in the case of an aromatic or an araliphatic radical may bear no or in at least one ortho position to the aromatic carbon atom bearing the carbodiimide group, aliphatic and / or cycloaliphatic substituents having at least 2 carbon atoms which may also carry heteroatoms,

R '= Ci - Cig alkyl, C ₅ -C ₈ cycloalkyl, aryl, C ₇ -C ₈ - aralkyl, -R NHCOS- R ^1,

R-COO R ¹ , -R-O R ¹ , -RN (R ^l ) ₂ , -R-SR ¹ , -R-OH, -R-NH ₂ , -R-NHR ¹ ,

-R-epoxy, -R-NCO, -R-NHCONHR ¹ , -R-NHCONR'R ² or

-R-NHCOOR ³ , where R = aromatic, aliphatic, cycloaliphatic and / or araliphatic radical,

R "= H, -N = C = N-aryl, -N = C = N-alkyl, -N = C = N-cycloalkyl, -N = C = N-aralkyl, -NCO, -NHCONHR ¹ , -NHCONR 'R ² , -NHCOOR ³ , -NHCOS-R ¹ , -COO R ¹ , -OR ¹ , -NR,

-SR ¹ , -OH, -NH ₂ , -NH R ¹ , wherein in R 'and R''independently of one another R ¹ and R ^{2 are} identical or different and a Ci - C ₂ o-alkyl, C ₃ -C ₂₀ -cycloalkyl, -aryl, C ₇ -C ₈ -aralkyl radical, 01-oligo- / polyethylene and / or -Propylenglykole and R ^{3 has} one of the meanings of R ¹ or a polyester or a polyamide radical, and m corresponds to an integer from 2 to 5,000 corresponds, in oligomeric carbodiimides m is an integer from 2 to 5, and in the case of polymeric carbodiimides m corresponds to an integer of> 5, and / or at least one carbodiimide of the formula (III)

R '- [- (- N = C = NY-) _p - (- B -) _q -] ₀ -X (III), with

Y = arylene, C ₇ -C ₁₈ -aralkylene

p = an integer from 1 to 500, preferably 1 to 100,

B = -NH-CO-NH-Z-, -NH-COO-Z-, -NH-COS-Z-,

q = an integer from 1 to 500, preferably 1 to 100,

o = an integer from 1 to 500, preferably 1 to 100, wherein

either p or o must be> 1.

X = H, -OH, -SH, -NH ₂ , -OR ¹ , -Ν ^) ₂ , -SR ¹ , -NHR ¹ , NR ^ ² , -OCO-NH-R ^' , NH CO-, -NH -R-, -S-CO-NH-R ^'

R '= Ci-Cig-alkyl, C ₅ -C _lg -cycloalkyl, aryl, C ₇ -Cig-aralkyl, - R "' -NH-COS-R ¹ , -R ^ -COOR ¹ , -R ^ -OR ¹ , -R '"- ^ ¹ ^ - R"' -SR ¹ , ~ R "'--OH, -R'" - NH ₂ , -R ^ -NHR ¹ ,

-R "'-Epoxy, - R"' - NCO, --R ^ -NHCONHR ¹ , -R ^ -NHCONR ^ ² or - R "'- NH-COOR ³ , wherein

R ^l and R ² are identical or different and represent a Ci-C ₂ o alkyl, C3-C ₂₀ cycloalkyl, aryl, C7-C _lg -Arylkylrest, 01igo- / polyethylene and / or propylene glycols and R ³ is has the meanings of R ¹ or a polyester or a polyamide radical, Z =

Y, polyester, polyether, polyamides and R '"is an aromatic and / or araliphatic radical.

4. Bio-based plastics according to one or more of claims 1 to 3, characterized in that it is the oligomers used and / or polymeric

Carbodiimides are preferably aromatic compounds.

5. Biobased plastics according to one or more of claims 1 to 4, characterized in that the polymeric and / or oligomeric carbodiimide are compounds of the formula (II) in which R '' l, 3-substituted-2, 4,6

Triisopropylphenyl and / or 1,3-bis (1-methyl-1-isocyanatoethyl) benzene and / or tetramethylxylylene derivatives and / or 2,4-substituted tolylene and / or 2,6- substituted tolylene and / or mixtures of 2,4- or 2,6-substituted tolylene corresponds.

6. bio-based plastics according to one or more of claims 1 to 5, characterized in that it is the polyhydroxyalkanoate to a compound of formula

(I)

(I) is, in which n> 10 and R is a Cr to Ct ₄ alkyl corresponds.

Process for the preparation of bio-based plastics according to one or more of Claims 1 to 6, characterized in that at least one polyhydroxyalkanoate is mixed with at least 0.5% by weight of at least one oligomeric and / or polymeric aromatic and / or araliphatic carbodiimide in a mixing unit.

Use of the bio-based plastics according to one or more of claims 1 to 7 in long-life applications in electronics, automotive, construction, transportation, in the household, as office supplies or in applications under "severe conditions".