Foamed pellets comprising polyesters

Abstract

The present invention relates to foamed pellets comprising a composition (CB) a first polymer selected from the group consisting of aliphatic-aromatic polyesters and aliphatic polyesters based on aliphatic dicarboxylic acids and aliphatic dihydroxyl compounds as component (C1) in an amount of from 85 to 99.9% by weight based on the sum of components (C1) and (C2); and a second polymer which is different from the first polymer, and the second polymer is selected from the group consisting of aliphatic-aromatic polyesters, aliphatic polyesters based on aliphatic dicar- boxylic acids and aliphatic dihydroxyl compounds, polycaprolactone (PCL), ester based thermoplastic polyurethanes and polylactic acid (PLA) as component (C2) in an amount of from 0.1 to 12% by weight based on the sum of compo- nents (C1) and (C2). Furthermore, the present invention relates to a process for preparing foamed pellets, the pro- cess comprising the steps of providing the composition (CB); mixing the composition (CB) with a blowing agent, pref- erably in an amount of from 0.5 to 3.5 wt %, based on the weight of the composition (CB); forming pellets of the im- pregnated composition; and expanding the pellets to obtain the foamed pellets. The present invention also relates to a process for preparing a molded body, comprising providing foamed pellets according to the invention and fusing the foamed pellets and the molded body obtained in the process.

Description

[0001] Foamed pellets comprising polyesters

[0002] The present invention relates to foamed pellets comprising a composition (CB) a first polymer selected from the group consisting of aliphatic-aromatic polyesters and aliphatic polyesters based on aliphatic dicarboxylic acids and aliphatic dihydroxyl compounds as component (C1) in an amount of from 85 to 99.9% by weight based on the sum of components (C1) and (C2); and a second polymer which is different from the first polymer, and the second polymer is selected from the group consisting of aliphatic-aromatic polyesters, aliphatic polyesters based on aliphatic dicarboxylic acids and aliphatic dihydroxyl compounds polycaprolactone (PCL), ester-based thermoplastic polyurethanes and polylactic acid (PLA) as component (C2) in an amount of from 0.1 to 12% by weight based on the sum of components (C1) and (C2). Furthermore, the present invention relates to a process for preparing foamed pellets, the process comprising the steps of providing the composition (CB); mixing the composition (CB) with a blowing agent, preferably in an amount of from 0.5 to 3.5 wt %, based on the weight of the composition (CB); forming pellets of the impregnated composition; and expanding the pellets to obtain the foamed pellets. The present invention also relates to a process for preparing a molded body, comprising providing foamed pellets according to the invention and fusing the foamed pellets and the molded body obtained in the process.

[0003] Foamed pellets, which are also referred to as bead foams (or particle foams), and also molded bodies produced from them, based on thermoplastic polyurethane or other elastomers, are known (e.g. WO 94 / 20568 A1 , WO 2007 / 082838 A1 , WO2017 / 030835, WO 2013 / 153190 A1 , WO2010 / 010010 A1) and have manifold possible uses.

[0004] Within the meaning of the present invention, "foamed pellets” or else a "bead foam” or "particle foam” refers to a foam in bead form, wherein the average diameter of the beads is from 0.2 to 20 mm, preferably 0.5 to 15 mm and especially from 1 to 12 mm. In the case of non-spherical, e.g. elongate or cylindrical, beads, diameter means the longest dimension.

[0005] CN110172138 discloses biodegradable plastic foamed particles comprising adipic acid, terephthalic acid, 1 , 4-bu- tanediol and a catalyst, and processes for the preparation thereof.

[0006] Guoqun Zhao et al. (Journal of CO2 Utilization 64 (2022) 102149 and Journal of CO2 Utilization 72 (2023) 102495) describe microcellular foaming of poly (butylene adipate-co-terephthalate) (PBAT). Using N2, CO2 co-blowing agents, PBAT foams with a high expansion ratio of 14.9-fold (84g / L density) and a restricted shrinkage of less than 6% were produced by using microcellular foaming.

[0007] WO2018 / 029040 discloses a process for production of expanded foam beads of one or more polyesters based on aliphatic or aliphatic and aromatic dicarboxylic acids and aliphatic diols, comprising the preparation of foamed pellets from a melt of the polyester and carbon dioxide and / or nitrogen blowing agent and also 0.1 to 2 wt % of a nucleating agent. WO 2015 / 052020 discloses a process for production of expanded foam beads from a biodegradable polyester based on aliphatic, or aliphatic and aromatic, dicarboxylic acids and aliphatic diols.

[0008] WO 2014 / 198779 describes an extrusion process for production of expanded foam beads from, among other materials, aromatic polyesters, this process operating without organic blowing agents. Application of that process to the production of foam beads from biodegradable polyesters, however, has not afforded satisfactory results. The stability of the foamed pellets disclosed in the state of the art as well of the molded bodies prepared from the foamed pellets is not sufficient for many applications.

[0009] In many applications today, especially in the footwear industry, there is a demand for materials that combine high rebound (>70 %), low component density (<220 g / L), and low part shrinkage (<1 %). To achieve low component density, the immediate bulk density must be reduced. However, many of the foams used today tend to shrink. Typically, the shrinkage of the foamed beads described in the state of the art is often larger than 30 %, leading to increased bulk densities and collapsed bead surfaces with inadequate optics. In addition to bead shrinkage, shrinkage after molding is also a common problem in part manufacturing and often larger than 1 %. Furthermore, many of the shoe materials used today are not biodegradable. Biodegradable materials are preferred for future applications, particularly for applications where fine polymer abrasion is expected (e.g., in the sole area of shoes). Only a few biodegradable thermoplastic elastomers based on biodegradable polyester such as PBAT or PBSet are described in the state of the art. However, PBAT bead foams have low rebound (<70%). On the other hand, previous PBSet foams exhibit high rebound values, but also tend to have high bead shrinkage (>30%). The combination of preferred material properties (rebound>70%, bead shrinkage<20%, component density<220g / L, biodegradable polymer) cannot be achieved with the current state of the art.

[0010] In principle, there is a need for foamed pellets or bead foams which have good processability to give the corresponding molded bodies with advantageous mechanical properties. Sufficient bonding or fusion of the foamed pellets is essential in order to obtain advantageous mechanical properties of the molding produced from the foamed pellets.

[0011] Furthermore, it is desirable that the foamed pellets and the molded bodies obtained have low abrasion to reduce the pollution caused by micro plastic. If abrasion occurs, it is preferred that the abraised material is biodegradable.

[0012] Within the context of the present invention, "advantageous mechanical properties” are to be interpreted with respect to the intended applications. The most prominent application for the subject matter of the present invention is the application in the shoe sector, where the foamed pellets can be used for molded bodies for constituent parts of the shoe in which damping and / or cushioning is relevant, for example intermediate soles and insoles but also outer soles.

[0013] Furthermore, it is of interest to provide materials which are at least partially based on renewable materials and preferably also biodegradable materials. Therefore, it was an object of the present invention to provide foamed pellets preferably prepared from biodegradable polymers which have sufficient stability as well as a process for their preparation.

[0014] This object was achieved by foamed pellets comprising a composition (CB) comprising

[0015] (a) a first polymer selected from the group consisting of aliphatic-aromatic polyesters and aliphatic polyesters based on aliphatic dicarboxylic acids and aliphatic dihydroxyl compounds as component (C1 ) in an amount of from 85 to 99.9% by weight based on the sum of components (C 1 ) and (C2);

[0016] (b) a second polymer which is different from the first polymer, and the second polymer is selected from the group consisting of aliphatic-aromatic polyesters, aliphatic polyesters based on aliphatic dicarboxylic acids and aliphatic dihydroxyl compounds, polycaprolactone (PCL), ester-based thermoplastic polyurethanes and polylactic acid (PLA) as component (C2) in an amount of from 0.1 to 12% by weight based on the sum of components (C1) and (C2).

[0017] Preferably, the object is achieved by foamed pellets comprising a composition (CB) comprising

[0018] (a) a first polymer selected from the group consisting of aliphatic-aromatic polyesters and aliphatic polyesters based on aliphatic dicarboxylic acids and aliphatic dihydroxyl compounds as component (C1) in an amount of from 85 to 98% by weight based on the sum of components (C1) and (C2);

[0019] (b) a second polymer which is different from the first polymer, and the second polymer is selected from the group consisting of aliphatic-aromatic polyesters, aliphatic polyesters based on aliphatic dicarboxylic acids and aliphatic dihydroxyl compounds, polycaprolactone (PCL), ester-based thermoplastic polyurethanes and polylactic acid (PLA) as component (C2) in an amount of from 2 to 12% by weight based on the sum of components (C 1) and (C2).

[0020] The present invention also relates to foamed pellets comprising a composition (CB) comprising

[0021] (a) a first polymer selected from the group consisting of aliphatic-aromatic polyesters and aliphatic polyesters as component (C1) in an amount of from 85 to 99.9% by weight based on the sum of components (C1) and (C2);

[0022] (b) a second polymer which is different from the first polymer, and the second polymer is selected from the group consisting of aliphatic-aromatic polyesters, aliphatic polyesters, polycaprolactone (PCL), ester-based thermoplastic polyurethanes and polylactic acid (PLA) as component (C2) in an amount of from 0.1 to 15% by weight based on the sum of components (C1) and (C2).

[0023] The present invention also relates to foamed pellets comprising a composition (CB) comprising

[0024] (a) a first polymer selected from the group consisting of aliphatic-aromatic polyesters and aliphatic polyesters as component (C1) in an amount of from 85 to 98% by weight based on the sum of components (C1) and (C2); (b) a second polymer which is different from the first polymer, and the second polymer is selected from the group consisting of aliphatic-aromatic polyesters, aliphatic polyesters, polycaprolactone (PCL), ester-based thermoplastic polyurethanes and polylactic acid (PLA) as component (C2) in an amount of from 2 to 15% by weight based on the sum of components (C1) and (C2).

[0025] It has surprisingly been found that the use of the combination of the components (C1) an (C2) used according to the invention allows to prepare foamed pellets which have a high modulus of elasticity at room temperature and only little shrinkage, so that the foamed pellets can be readily processed into molded bodies and at the same time have low abrasion. Preferably, the materials are also based on renewable materials and are biodegradable. In addition, the inventive foamed pellets feature good mechanical properties, such as for example high elasticity and good rebound.

[0026] Surprisingly, the foamed pellets can be fused to prepare molded bodies using only small amounts of energy.

[0027] In the context of the present invention, "biodegradable” is determined according to DIN EN 13432 (2000-12) unless otherwise noted. Biodegradability in the sense of compostability is quantifiable, for example, by mixing the material with compost and storing the mixture for a certain time. According to DIN EN 13432 (which makes reference to ISO 14855), for example, CO2 -free air is caused to flow through ripened compost during composting, and the ripened compost is subjected to a defined temperature program. Biodegradability here is defined via the ratio of the net CO2 release of the sample (after deduction of the CO2 release by the compost without sample) to the maximum CO2 release of the sample (calculated from the carbon content of the sample), as a percentage degree of biodegradation. Biodegradable polyesters (and polyester mixtures) generally show clear signs of degradation, such as fungal growth, cracking and holing, after just a few days of composting.

[0028] Within the context of the present invention, unless otherwise stated, the rebound is determined analogously to DIN 53512, April 2000; the deviation from the standard is the test specimen height which should be 12 mm, but in this test 20 mm is used in order to avoid "penetration through” the sample and measurement of the substrate.

[0029] A suitable method to determine the amount of bio based and fossil-based components is for example the determination of the C14 content (C14 method).

[0030] According to the present invention the foamed pellets comprise composition (CB). According to a further embodiment, the foamed pellets consist of the composition (CB) according to the present invention. The composition (CB) comprises components (C1) and (C2) but may also comprise further components.

[0031] Preferably, the composition (CB) comprises the components (C1) and (C2) in an amount of 70 to 100% by weight based on the composition (CB), in particular 80 to 99% by weight, i.e. the composition preferably comprises further components in an amount of from 0 to 30% by weight, in particular in an amount of 1 to 20% by weight based on the composition (CB). According to the present invention, the composition (CB) may also consist of components (01) and (C2).

[0032] As component (C1) the composition (CB) comprises a first polymer selected from the group consisting of aliphatic- aromatic polyesters and aliphatic polyesters based on aliphatic dicarboxylic acids and aliphatic dihydroxyl compounds. According to the present invention, composition (CB) comprises component (C1) in an amount of from 85 to 99.9% by weight based on the sum of components (01) and (02), preferably in an amount of from 85 to 98% by weight based on the sum of components (01) and (02), more preferably in an amount of from 90 to 95% by weight based on the sum of components (01) and (02).

[0033] As component (02), composition (CB) comprises a second polymer which is different from the first polymer, and the second polymer is selected from the group consisting of aliphatic-aromatic polyesters, aliphatic polyesters based on aliphatic dicarboxylic acids and aliphatic dihydroxyl compounds, polycaprolactone (PCL), and polylactic acid (PLA). Composition (CB) comprises component (02) in an amount of from 0.1 to 15, in particular 0.1 to 12% by weight based on the sum of components (01) and (02), preferably in an amount of from 2 to 15, more preferable from 2 to 10% by weight based on the sum of components (C1) and (C2), more preferably on an amount of from 5 to 10% by weight based on the sum of components (C1) and (C2).

[0034] In principle, aliphatic-aromatic polyesters and aliphatic polyesters suitable as component (C1) are known and may be selected from polyesters based on aliphatic or aliphatic and aromatic dicarboxylic acids and aliphatic diols. According to a further embodiment, the present invention also relates to the foamed pellets as disclosed above, wherein the component (C1) is selected from poly(butylene sebacate-co-terephthalate (PBSeT) copolyesters.

[0035] The number average molecular weight (Mn) of the aliphatic or aromatic-aliphatic polyesters measured in a hexafluoroisopropanol (HFIP) solution against narrow polymethylmethacrylate (PMMA) standards with a cutoff at 500 g / mol is generally in the range from 5000 to 100 000, preferably in the range from 10 000 to 75 000 g / mol, and more preferred in the range from 15000 to 50 000 g / mol, their weight average molecular weight (Mw) is generally in the range from 30 000 to 300 000, preferably 60 000 to 200 000 g / mol, preferably > 80 000, more preferable > 90 000 and in particular > 100 000 g / mol, and their Mw / Mn ratio is generally in the range from 1 to 6, preferably in the range from 2 to 4.

[0036] According to a further embodiment, the present invention also relates to the foamed pellets as disclosed above, wherein component (C1) is selected from poly (butylene sebacate-co-terephthalate (PBSeT) copolyesters with a molecular weight (Mw) of > 100 kg / mol, determined using GPC (HFIP, PMMA standard).

[0037] Also polymers suitable as component (C2) are in principle known. According to a further embodiment, the present invention also relates to the foamed pellets as disclosed above, wherein component (C2) is selected from the group consisting of aliphatic-aromatic polyesters, aliphatic polyesters based on aliphatic dicarboxylic acids and aliphatic dihydroxyl compounds, polycaprolactone (PCL), and ester based thermoplastic polyurethanes. According to a further embodiment, the present invention also relates to the foamed pellets as disclosed above, where the component (C2) is selected from polybutylene succinate (PBS) and polylactic acid (PLA), preferably from polybutylene succinate (PBS).

[0038] Preferably one or both of components (C1) and (C2) are biodegradable or biobased. On a preferred embodiments of the present invention, component (01) or the component (02) or the component (01) and the component (02) are biobased polymers.

[0039] According to a further embodiment, the present invention also relates to the foamed pellets as disclosed above, where the component (01) or the component (02) or the component (01) and the component (02) are biobased polymers.

[0040] Composition (OB) may also comprise further components, in particular further polymers. Further polymers may be selected from a wide range of polymers to adjust the properties of the composition (OB) and the foamed pellets. In particular, the addition of further biodegradable polymers results in advantageous properties of the foamed pellets and the composition (OB) is preferably biodegradable.

[0041] Polyesters based on aliphatic, or aliphatic and aromatic, dicarboxylic acids and aliphatic dihydroxy compounds, are suitable as component (01). Latter polyesters are also termed partly aromatic polyesters. Preferably, these polyesters are biodegradable to DIN EN 13432. Mixtures of two or more such polyesters may also be used.

[0042] Suitable biodegradable aliphatic-aromatic polyesters may be derived from: b-1) 20 bis 70 mol-%, based on the total amount of components b-1) and b-2), of at least one aliphatic Ce-C dicarboxylic acid or Ce-C dicarboxylic acid derivative, b-2) 80 bis 30 mol-%, based on the total amount of components b-1) and b-2), of at least one aromatic dicarboxylic acid or aromatic dicarboxylic acid derivative, b-3) 98 to 102 mol-%, based on the total amount of b-1) and b-2), of an aliphatic C2-C10 diol, b-4) 0 to 2 wt%, based on the total weight of components b-1), b-2) and b-3), of an at least trihydric alcohol, and b-5) 0 to 2 wt%, based on the total weight of components b-1), b-2) and b-3), of a chain extender.

[0043] The aliphatic Ce- Cis dicarboxylic acids and Ce- G dicarboxylic acid derivatives b-1) are preferably selected from Ce - C16, more preferably from Ce - C13 dicarboxylic acids, their derivatives and mixtures thereof. Preferably they are a, co-dicarboxylic acids. The derivatives may be the Ci - Ce dialkyl esters or anhydrides. Examples of the Ci - Ce dialkylesters are dimethyl, diethyl, di-n-propyl, diisopropyl, di-n-butyl, diisobutyl, di-tert-butyl, di-n-pentyl, diisopentyl, and di n-hexylesters. Preferred are the Ci - C4 dialkyl esters and in particular preferred are the dimethyl esters. Examples of suited aliphatic dicarboxylic acids and their derivatives are adipic acid, pimelic acid, suberic acid, azelaic acid, sebacic acid, undecanedioic acid, dodecanedioic acid, brassylic acid, tetradecanedioic acid, pentadecanedioic acid, hexadecanedioic acid, heptadecanedioic acid, octadecanedioic acid, their derivatives, in particular the Ci - C4 dialkyl esters, and mixtures thereof. Preferably the aliphatic Ce- C dicarboxylic acids are selected from adipic acid, azelaic acid, sebacic acid, 1,12-dodecanoic acid, brassylic acid, their derivatives, more preferred the Ci - C4 alkyl esters, and mixtures thereof. In particular preferred the aliphatic dicarboxylic acids are selected from adipic acid, azelaic acid, sebacic acid and brassylic acid, their Ci - C4 alkyl esters, and mixtures thereof. Azelaic acid, sebacic acid, and brassylic acid have the additional advantage of being available from renewable raw materials. Most preferred is sebacic acid, its derivatives and mixtures thereof.

[0044] The aliphatic Ce-C dicarboxylic acids and their derivatives b-1) may be selected from mixtures of at least two aliphatic acids or their derivatives. Preferred are mixtures comprising a first aliphatic dicarboxylic acid selected from adipic acid, sebacic acid, derivatives thereof, and mixtures thereof, and a second aliphatic dicarboxylic acid selected from suberic acid, azelaic acid, undecanedioic acid, dodecanedioic acid, brassylic acid, tetradecanedioic acid, pentadecanedioic acid, hexadecanedioic acid, heptadecanedioic acid, octadecanedioic acid, their derivatives, and mixtures thereof. More preferred are mixtures comprising sebacic acid and / or a derivative thereof with one or more aliphatic acid selected from adipic acid, azelaic acid, brassylic acid, their derivatives and mixtures thereof as well as mixtures comprising adipic acid and / or a derivative thereof with one or more aliphatic acid selected from sebacic acid, azelaic acid, brassylic acid, their derivatives and mixtures thereof. Most preferred are mixtures of sebacic acid and / or a derivative thereof with azelaic acid and / or a derivative thereof; mixtures of sebacic acid and / or derivative thereof with adipic acid and / or a derivative thereof; and mixtures of adipic acid and / or a derivative thereof with azelaic acid and / or a derivative thereof. Preferred derivatives of the dicarboxlic acids are the Ci - C4 dialkyl esters.

[0045] The aromatic dicarboxylic acids or aromatic dicarboxylic acid derivatives b-2) are preferably selected from aromatic and heteroaromatic C6-C12 dicarboxylic acids, more preferred from aromatic and heteroaromatic Ce-Cs dicarboxylic acids, and their derivatives. Examples of such aromatic and heteroaromatic dicarboxylic acids and derivatives are terephthalic acid, isophthalic acid, 2,6-naphthoic acid and 1 ,5-naphthoic acid, 2,5-furandicarboxylic acid, 2,4-furandi- carboxylic acid, 2,3-furandicarboxylic acid, 3,4-furandicarboxylic acid, their Ci-Ce dialkyl esters, their anhydrides, where applicable, and mixtures thereof. Preferred are the C1-C4 dialkyl esters, in particular preferred are methyl esters. Examples of the Ci-Ce -dialkylesters are dimethyl, diethyl, di-n-propyl, diisopropyl, di-n-butyl, diisobutyl, di— tertbutyl, di-n-pentyl, diisopentyl, and di-n-hexylesters. Preferably the aromatic dicarboxylic acids or their derivatives are selected from terephthalic acid, 2,5-furandicarboxylic acid and their derivatives, preferably their C1-C4 alkyl esters. In particular preferred are terephthalic acid and its C1-C4 alkyl esters.

[0046] Preferably the biodegradable polyester b) is derived from b-1) 20 bis 70 mol %, based on the total amount of components b-1) and b-2), of at least one aliphatic C6-C13 dicarboxylic acid or C6-C13 dicarboxylic acid derivative, b-2) 80 bis 30 mol %, based on the total amount of components b-1) and b-2), of at least one dicarboxylic acid selected form terephthalic acid, furan dicarboxylic acid, their derivatives, and mixtures thereof.

[0047] The concentration of the aromatic dicarboxylic acid or aromatic dicarboxylic acid derivative b-2) is 80 to 30 mol-%, based on the total amount of components b-1) and b-2). In case the aromatic dicarboxylic acid or dicarboxylic acid derivative is terephthalic acid or a derivative thereof, its concentration in the polyester is preferably 70 to 30 mol-%. In case the aromatic dicarboxylic acid or dicarboxylic acid derivative is a furan dicarboxylic acid like 2,5-furandicarbox- ylic acid or a derivative thereof, its concentration in the polyester is preferably 80 to 50 mol-%, based on the total amount of components b-1) and b-2).

[0048] The aliphatic diol b-3) is selected from aliphatic C2-C10 diols, preferably from C2-C6 diols, more preferred from C2-C4 diols and in particular preferred from C3-C4 diols. Examples of suitable aliphatic C2-C10 diols are 1 ,2-ethanediol, 1 ,2- propanediol, 1 ,3-propanediol, 1 ,2-butanediol, 1 ,4-butanediol, 1 ,5-pentanediol, 2,2-dimethyl-1,3-propanediol (neopentyl glycol), 1 ,6-hexanediol, 2,4-dimethyl-2-ethyl-1,3-hexanediol, 2,2-dimethyl-1,3-propanediol, 2-ethyl-2-butyl-1 ,3-pro- panediol, 2-ethyl-2-isobutyl-1 , 3 propanediol and 2,2,4-trimethyl-1 ,6-hexanediol, cyclopentanediol, 1 ,4-cyclohex- anediol, 1 ,2-cyclohexanedimethanol, 1 ,3 cyclohexanedimethanol, 1 ,4-cyclohexanedimethanol, isosorbide, isoiodide and 2, 2, 4, 4-tetramethyl-1 , 3 cyclobutanediol. Preferred aliphatic C2-C10 diols are 1 ,2-ethanediol, 1 ,3-propanediol, 1 ,4- butanediol and 1 ,6-hexanediol, more preferred are 1,3-propanediol and 1 ,4-butanediol, most preferred is 1 ,4-butane- diol. It is also possible to use mixtures of different aliphatic diols. Preferably the aliphatic diol b-3) contains at least 50% by moles of one or more diols selected from 1,2-ethanediol, 1 ,3-propanediol, 1 ,6-hexanediol and 1 ,4-butanediol, in particular preferred at least 50% by moles 1 ,4-butanediol.

[0049] In particular preferred are diols generated from renewable resources like 1 ,4-butanediol from either direct fermentation (W02008 / 115840) or from the hydrogenation of biobased succinic acid or 1,3-propanediol from fermentation developed by DuPont and Tate & Lyle.

[0050] The aliphatic diol b-3) is present in a concentration of 98 to 102 mol-%, based on the based on the total amount of b- 1) and b-2).

[0051] Preferred biodegradable polyesters b) are derived from b-1) 20 bis 70 mol %, based on the total amount of components b-1) and b-2), of at least one aliphatic C6-C13 dicarboxylic acid or C6-C13 dicarboxylic acid derivative, b-2) 80 bis 30 mol %, based on the total amount of components b-1) and b-2), of at least one dicarboxylic acid selected form terephthalic acid, furan dicarboxylic acid, their derivatives, and mixtures thereof, b-3) 98 to 102 mol %, based on the total amount of b-1) and b-2), of an aliphatic C3-C4 diol, b-4) 0 to 2 wt%, based on the total weight of components b-1), b-2) and b-3), of an at least trihydric alcohol, and b-5) 0 to 2 wt%, based on the total weight of components b-1), b-2) and b-3), of a chain extender. More preferred are aliphatic-aromatic polyesters wherein the aliphatic Ce-C dicarboxylic acid and its derivative b-1) are selected from adipic acid, azelaic acid, sebacic acid, 1 , 12-dodecanedioic acid, brassylic acid, their derivatives, and mixtures thereof; wherein the aromatic dicarboxylic acid and aromatic dicarboxylic acid derivative b-2) are selected from terephthalic acid, 2,5-furandicarboxylic acid, their derivatives and mixtures thereof; and wherein the diol b-3) is 1 ,4-butanediol. The dicarboxylic acid derivatives are preferably the Ci -C4 alkyl esters, in particular the methyl esters.

[0052] The biodegradable polyester b) may contain a branching agent as component b-4), which contains at least three functional groups which are capable of reacting with a diol or a dicarboxylic acid. Examples are at least trihydric alcohols like glycerol, trimethylolpropane, trimethylolethane, pentaerythritol, polyethertriols and sorbitol or carboxylic acids and hydroxy acids or anhydrides containing three or more groups selected from carboxylic acid groups, carboxylic acid anhydride groups and hydroxy groups like tartaric acid, citric acid, malic acid, trimesic acid, trimellitic acid, trimellitic anhydride, pyromellitic and pyromellitic dianhydride, preferred are trimethylolpropane, pentaerythritol, and glycerol, in particular preferred are trimethylolpropane and glycerol. Component b-4) can be used to construct biodegradable polyesters having structural viscosity. Melt rheology improves in that the biodegradable polyesters become easier to process, for example easier to pull into self-supporting films / sheets by melt solidification.

[0053] The concentration of the at least trifunctional branching agent b-4) in the biodegradable polyester is 0 to 2 wt%, based on the total weight of components b-1), b-2) and b-3) in the final polyester. In case the at least trifunctional branching agent b-4) is present in the biodegradable polyester, the concentration is usually 0.01 to 2 wt%, preferably 0.05 to 1 wt%, and particular preferred 0.08 to 0.20 wt%, based on the total weight of components b-1), b-2) and b-3) in the final polyester.

[0054] The biodegradable polyester b) may comprise as component b-5) a chain extender. Chain extenders are polyfunctional and especially difunctional isocyanates, isocyanurates, oxazolines, carboxylic anhydrides, carbodiimides or epoxides.

[0055] The term "epoxides” is to be understood as meaning particularly epoxy-containing copolymer based on styrene, acrylic ester and / or methacrylic ester, preferably of the sty rene-glycidylether-methylmethacry late type. The units which bear epoxy groups are preferably glycidyl (meth)acrylates. Copolymers having a glycidyl methacrylate content of greater than 20, more preferably greater than 30 and even more preferably greater than 50 wt% of the copolymer will be found particularly advantageous. Epoxy-containing copolymers of the abovementioned type are commercially available, for example from BASF Resins B.V. under the Joncryl® ADR brand. Joncryl® ADR 4468 and ADR 4400 are particularly useful as chain extender.

[0056] Difunctional isocyanates may be aromatic or aliphatic diisocyanates. Examples of aromatic diisocyanates are tolylene 2,4-diisocyanate, tolylene 2,6-diisocyanate, 2,2'-diphenylmethane diisocyanate, 2,4'-diphenylmethane diisocyanate, 4,4'-diphenylmethane diisocyanate, naphthylene 1,5-diisocyanate or xylylene diisocyanate. Of these, particular preference is given to 2,2'-, 2,4'- and also 4,4'-diphenylmethane diisocyanates. In general, the latter diisocyanates are used as a mixture. The diisocyanates may also comprise minor amounts, for example up to 5% by weight, based on the total weight, of urethione groups, for example for capping the isocyanate groups.

[0057] The term "aliphatic diisocyanate” herein refers particularly to linear or branched alkylene diisocyanates or cycloalkylene diisocyanates having 2 to 20 carbon atoms, preferably 3 to 12 carbon atoms, for example 1 ,6-hexamethylene diisocyanate, 1 ,5-pentamethylene diisocyanate, isophorone diisocyanate or methylenebis(4-isocyanatocyclohexane). Particularly preferred aliphatic diisocyanates are isophorone diisocyanate and, in particular, 1 ,6-hexamethylene diisocyanate.

[0058] The preferred isocyanurates include the aliphatic isocyanurates which derive from alkylene diisocyanates or cycloalkylene diisocyanates having 2 to 20 carbon atoms, preferably 3 to 12 carbon atoms, for example isophorone diisocyanate or methylenebis(4-isocyanatocyclohexane). The alkylene diisocyanates here may be either linear or branched. Particular preference is given to isocyanurates based on n hexamethylene diisocyanate, for example cyclic trimers, pentamers or higher oligomers of 1 ,6-hexamethylene diisocyanate.

[0059] 2,2'-Bisoxazolines are generally obtainable via the process from Angew. Chem. Int. Ed., Vol. 11 (1972), pp. 287-288. Particularly preferred bisoxazolines are those in which R1 is a single bond, a (CH2)z alkylene group, where z = 2, 3 or 4, such as methylene, 1 ,2-ethanediyl, 1 ,3-propanediyl, 1 ,2-propanediyl or a phenylene group. Particularly preferred bisoxazolines are 2,2’-bis(2— oxazoline), bis(2-oxazolinyl)methane, 1 ,2-bis(2— oxazolinyl)ethane, 1 ,3-bis(2— oxa- zolinyl)propane or 1,4-bis(2— oxazolinyl)butane, in particular 1 ,4-bis(2-oxazolinyl)benzene, 1 ,2-bis(2— oxazolinyl)ben- zene or 1,3-bis(2-oxazolinyl)benzene.

[0060] Carbodiimides and polymeric carbodiimides are marketed by way of example by Lanxess with trademark Stabaxol® or by BASF Polyurethane GmbH with trademark Elastostab® or Carbodilite HMV-15CA and Carbodilite HMV-5CA- LC from Nisshinbo Chemical Inc.

[0061] Examples are poly(4, 4'-dicyclohexylmethane carbodiimide) (Carbodilite® type), poly(isophorone carbodiimide), poly(meta-tetramethylxylylene carbodiimide) (Elastostab® type), poly(2,2',6,6'-tetraisopropyldiphenylene carbodiimide) (Stabaxol® D), poly(2,4,6-triisopropyl-l,3-phenylene carbodiimide) (Stabaxol® P- 100), poly(2,6 diisopro- pyl- 1 ,3-phenylene carbodiimide) (Stabaxol® P).

[0062] Preferably the chain extender b-5) is selected from isophorone diisocyanate, 1,6-hexamethylene diisocyanate, 1 ,5- pentamethylendiisocyanate, 4,4-diphenylmethane diisocyanate, and epoxy-containing copolymers based on styrene, acrylic ester and methacrylic ester, preferably of the styrene-glycidy lether-methy I methacrylate type. The concentration of the chain extender b-5) is 0 to 2 wt%, based on the total weight of components b-1), b-2) and b- 3). In case the chain extender b-5) is present its concentration is in the range of 0.01 wt.-% to 2 wt.-%, based on the total weight of components b-1), b-2) and b-3).

[0063] The number average molecular weight (Mn) of the aromatic-aliphatic polyesters used as component b) measured in a Hexafluoroisopropanol (HFIP) solution against narrow polymethylmethacrylate (PMMA) standards and a molecular weight exclusion limit of 500 - 1 000 000 g / mol is generally in the range from 5 000 to 100 000, preferably in the range from 10 000 to 75 000 g / mol, and more preferred in the range from 15 000 to 50 000 g / mol, their weight average molecular weight (Mw) is generally in the range from 30 000 to 300 000, preferably 60 000 to 200 000 g / mol, and their Mw / Mn ratio is generally in the range from 1 to 6, preferably in the range from 2 to 4. The viscosity number is between 30 and 450 g / mL and preferably in the range from 50 to 400 g / mL Here and throughout the specification, the viscosity number (VN) is determined according to DIN 53728-3:1985-1 at 25 °C using a solution of the respective polymer in a 50:50 w / w mixture of phenol and 1 ,2- dichlorobenzene. The melting point measured at 50% relative humidity at 23 °C by DSC with a heating rate of 20 °C is in the range from 85 to 150°C and preferably in the range from 95 to 140°C.

[0064] Polyesters suited for the use in the polymer composition generally have a melt volume rate (MVR) to EN ISO 1133 (190°C, 2.16 kg weight) of 0.5 to 40 cm3 / 10 min and preferably of 0.8 to 15 cm3 / 10 min.

[0065] Examples of biodegradable aliphatic-aromatic polyesters are poly(butylene-co-adipate-co-terephthalate) (“PBAT”), poly(butylene-co-sebacate-co-terephthalate) ("PBSeT”), poly(butylene-co-azelate-co-terephthalate) ("PBAzT”), poly(butylene-co-adipate-co-sebacinate-co-terephthalate) ("PBASeT”), poly(butylene-co-adipate-co-azelate-co-ter- ephthalate) ("PBAAzT”), poly(butylene-co-adipate-co-brassylate-co-terephthalate) ("PBABrT”), poly(butylene-co- azelate-co-sebacinate-co-terephthalate) ("PBAzSeT”), poly(butylene-co-azelate-co-brassylate-co-terephthalate) ("PBAzBrT”), poly(butylene-co-brassylate-co-sebacinate-co-terephthalate) ("PBBrSeT”), poly(butylene-co-azelate- co-2,5-furanoate) (“PBAzF”), and poly(butylene-co-sebacate-co-2,5-furanoate) ("PBSeF”). Preferred are poly (butyl- ene-co-sebacate-co-terephthalate), poly (butylene adipate-co-terephthalate), poly (butylene azelate-co-terephthalate), poly (butylene adipate-co-sebacate-co-terephthalate), poly (butylene adipate-co-azelate-co-terephthalate), poly (butylene azelate-co-sebacate-co-terephthalate and mixtures thereof. In particular preferred is poly(butylene-co-sebacate- co-terephthalate)

[0066] Biodegradable aliphatic-aromatic polyesters as described above are commercially available, e.g. under the trade- name ecoflex® by BASF.

[0067] Especially preferred are the following aliphatic-aromatic polyesters: polybutylene adipate-coterephthalate (PBAT), polybutylene sebacate-coterephthalate (PBSeT) or polybutylene succinate-coterephthalate (PBST), and very preferably polybutylene adipate terephthalate (PBAT) and polybutylene sebacate terephthalate (PBSeT). Additionally preferred are mixtures of polybutylene adipate terephthalate (PBAT) and polybutylene sebacate terephthalate (PBSeT).

[0068] Here and throughout the specification, aliphatic polyesters are understood to mean polyesters based on aliphatic dicarboxylic acids and aliphatic dihydroxyl compounds, and polyesters based on mixtures of aliphatic dicarboxylic acids with aliphatic dicarboxylic acids and aliphatic dihydroxyl compounds. To prepare the aliphatic-aliphatic polyesters, instead of the dicarboxylic acids, their respective ester-forming derivatives or mixtures thereof with the dicarboxylic acids may also be used.

[0069] Aliphatic dicarboxylic acids and the ester-forming derivatives thereof that are generally considered are those having 2 to 30 carbon atoms, preferably 4 to 26 carbon atoms, in particular preferred are aliphatic dicarboxylic acids having 4 to 13 carbon atoms or 18 to 26 carbon atoms. They may be either linear or branched. Preferably, the aliphatic dicarboxylic acids are aliphatic a, co-dicarboxylic acids. However, it is also possible in principle to employ dicarboxylic acids having a greater number of carbon atoms, for example having up to 50 carbon atoms.

[0070] Examples of aliphatic dicarboxylic acids and the ester-forming derivatives include, but are not limited to: oxalic acid, malonic acid, succinic acid, 2-methylsuccinic acid, glutaric acid, 2-methy Iglutaric acid, 3-methylglutaric acid, a-ke- toglutaric acid, adipic acid, pimelic acid, azelaic acid, sebacic acid, 1 , 12-dodecanedioic acid, brassylic acid, fumaric acid, 2,2-dimethy Iglutaric acid, suberic acid, diglycolic acid, oxaloacetic acid, glutamic acid, aspartic acid, itaconic acid and maleic acid, their anhydrides and their Ci to C4-alkyl esters. These dicarboxylic acids or the ester-forming derivatives thereof may be used individually or as a mixture of two or more thereof.

[0071] It is preferable to employ succinic acid, adipic acid, azelaic acid, sebacic acid, 1 , 12-dodecanedioic acid, brassylic acid or their respective ester-forming derivatives or mixtures thereof. It is particularly preferable to employ succinic acid, adipic acid or sebacic acid or the respective ester-forming derivatives thereof or mixtures thereof. Succinic acid, azelaic acid, sebacic acid and brassylic acid additionally have the advantage that they are obtainable from renewable raw materials.

[0072] Preferred examples of suitable aliphatic polyesters are, but not limited to aliphatic polyesters in which the aliphatic dicarboxylic acid is selected from succinic acid, adipic acid, azelaic acid, sebacic acid, 1 , 12-dodecanedioic acid, brassylic acid and mixtures thereof. Particular preference is given to succinic acid, adipic acid and sebacic acid and mixtures thereof.

[0073] Examples of aliphatic diols which are suitable for the preparation of the aliphatic polyesters are, for example, branched or linear alkanediols having 2 to 12 carbon atoms, preferably 4 to 6 carbon atoms, or cycloalkanediols having 5 to 10 carbon atoms. Examples of suitable alkanediols are ethylene glycol, 1 ,2-propanediol, 1 ,3 propanediol, 1 ,2-butanediol, 1 ,4-butanediol, 1 ,5 pentanediol, 2,4-dimethyl-2-ethylhexane-1 ,3-diol, 2,2-dimethyl-1 ,3-propanediol, 2 ethyl-2-butyl-1 ,3-propanediol, 2 ethyl-2-isobutyl-1 ,3-propanediol, 2,2,4-trimethyl-1 ,6-hexanediol, especially ethylene glycol, 1 ,3-propanediol, 1 ,4-butanediol and 2,2 dimethyl-1 ,3-propanediol (neopentyl glycol). Examples of cycloalkanediols are cyclopentanediol, 1 ,4-cyclohexanediol, 1 ,2 cyclohexanedimethanol, 1 ,3-cyclohexanedimethanol, 1,4- cyclohexanedimethanol and 2,2,4,4-tetramethyl-1 ,3-cyclobutanediol. The aliphatic polyesters may also comprise mixtures of different alkanediols condensed. In particular, preference is given to 1 ,4-butanediol and propane-1 , 3-diole, more particularly to 1 ,4-butanediol, especially in combination with one or two aliphatic dicarboxylic acids selected from succinic acid, adipic acid and sebacic acid. Propane-1 , 3-diol has an advantage that it is obtainable as a renewable raw material. 1 ,4-Butanediol is also obtainable from renewable raw materials. PCT / EP2008 / 006714 discloses a biotechnological process for the preparation of 1 ,4-butanediol starting from different carbohydrates using microorganisms from the class consisting of the Pasteurellaceae.

[0074] The aliphatic polyester may comprise structural units formed from one or more trifunctional alcohols, e.g. 1 , 1 , 1 -trimethylolpropane, 1, 1 ,1 -trimethylolethane, pentaerythrite, polyethertriols, and in particular glycerol, wherein preferably the weight fraction of structural units is 2 wt% or less, based on the total weight of the structural units aliphatic dicarboxylic acid(s) and aliphatic diol(s). Said trifunctional alcohols provide branching units.

[0075] The aliphatic polyester may also comprise structural units formed from one or more difunctional or oligofunctional species selected from the group consisting of isocyanates, isocyanurates, peroxides, epoxides, oxazolines, oxazines, caprolactams, carboxylic acid anhydrides and carbodiimides, wherein preferably the weight fraction of such structural units is preferably 4 wt% or less, based on the total weight of the structural units aliphatic dicarboxylic acid(s) and aliphatic diol(s). Said isocyanates, isocyanurates, peroxides, epoxides, oxazolines, oxazines, caprolactams, carboxylic acid anhydrides and carbodiimides act as chain extenders. A preferred chain extender is hexamethylenediisocyanate.

[0076] Examples of preferred aliphatic polyesters are poly (butylene succinate-co-adipate) (PBSA), poly (butylene succinate) (PBS), poly (butylene sebacate (PBSe), poly(butylene succinate-co-sebacate) (PBSSe)) and mixtures thereof. Even more preferred examples of aliphatic polyesters are poly (butylene succinate-co-adipate), poly(butylene succinate), poly (butylene succinate-co-sebacate) and mixtures thereof. Suitable aliphatic polyesters of this type are commercially available und the following product brands BioPBS™ by PTT-MCC.

[0077] The biodegradable polyesters may also comprise mixtures of the above-described partly aromatic polyesters and purely aliphatic polyesters, such as, for example, mixtures of polybutylene adipate-co-terephthalate and polybutylene succinate.

[0078] Composition (CB) according to the invention may comprise further adjuvants such as dyes, pigments, fillers, flame retardants, synergistics for flame retardants, antistats, stabilizers (such as hydrolysis stabilizers, for example), surface-active substances, and plasticizers in effective amounts. If fillers are present, they are, for example, organic and inorganic powders or fibrous materials and also mixtures thereof. Organic fillers which can be used include, for example, wood flour, starch, flax fibers, hemp fibers, ramie fibers, jute fibers, sisal fibers, cotton fibers, cellulose fibers or aramid fibers. Examples of suitable inorganic fillers include silicates, barite, glass beads, zeolites, metals or metal oxides. Particularly preferred for use are pulverulent inorganic substances such as chalk, talcum, kaolin, aluminum hydroxide, magnesium hydroxide, aluminum nitrite, aluminum silicate, barium sulfate, calcium carbonate, calcium sulfate, silica, finely ground quartz, Aerosil, argillaceous earth, mica or wollastonite, or inorganic substances in bead or fiber form, examples being iron powders, glass beads, glass fibers or carbon fibers. The average particle diameter or, in the case of fibrous fillers, the length of the fibers ought to be in the region of the cell size or less. Preference is given to an average particle diameter or average fiber length in the range from 0.1 to 100 pm, more particularly in the range from 1 to 50 pm.

[0079] Suitable flame retardants are, for example, tricresyl phosphate, tris(2-chloroethy I) phosphate, tris(2-chloropropy I) phosphate, tris(1 ,3-dichloropropyl) phosphate, tris-(2,3-dibromopropyl) phosphate, and tetrakis(2-chloroethyl)eth- ylene diphosphate. Apart from the halogen-substituted phosphates already stated, it is also possible to use inorganic flame retardants with red phosphorus, aluminum oxide hydrate, antimony trioxide, arsenic trioxide, ammonium polyphosphate and calcium sulfate, or cyanuric acid derivatives, melamine for example, or mixtures of at least two flame retardants— for example, ammonium phosphate and melamine— and also, optionally, starch and / or expandable graphite for conferring flame retardancy on the foamed polyesters produced.

[0080] The foamed pellets preferably have an average minimal diameter of 0.2 - 20 mm determined via 3D evaluation of the pellets, for example via dynamic image analysis with the use of a PartAn 3D optical measuring apparatus from Microtrac. According to a further embodiment, the present invention also relates to the foamed pellets as disclosed above, where the average diameter of the foamed pellets is in the range of from 0.2 to 20 mm.

[0081] The individual pellets preferably have an average mass in the range from 1 to 40 mg and particularly preferably in the range from 1 to 32 mg. This average mass of the pellets (particle weight) is determined as the arithmetic average by means of three weighing operations of in each case 10 pellet particles. According to a further embodiment, the present invention also relates to the foamed pellets as disclosed above, where the average mass of the foamed pellets is in the range of from 1 to 40 mg.

[0082] According to a further aspect, the present invention also relates to a process for preparing foamed pellets, the process comprising

[0083] (i) providing the composition (CB);

[0084] (ii) at least partially melting the composition (CB);

[0085] (iii) mixing the composition (CB) with a blowing agent, preferably in an amount of from 0.5 to 3.5 wt %, based on the weight of the composition (CB), to obtain a composition (CB*);

[0086] (iv) forming pellets of the composition (CB*);

[0087] (v) expanding the pellets to obtain the foamed pellets. In particular, the present invention is directed to a process for preparing foamed pellets, the process comprising

[0088] (i) providing the composition (CB); composition (CB) comprising

[0089] (a) a first polymer selected from the group consisting of aliphatic-aromatic polyesters and aliphatic polyesters based on aliphatic dicarboxylic acids and aliphatic dihydroxyl compounds as component (C1) in an amount of from 85 to 98% by weight based on the sum of components (C1) and (02);

[0090] (b) at second polymer which is different from the first polymer, and the second polymer is selected from the group consisting of aliphatic-aromatic polyesters, aliphatic polyesters based on aliphatic dicarboxylic acids and aliphatic dihydroxyl compounds, polycaprolactone (PCL), ester based thermoplastic polyurethanes and polylactic acid (PLA) as component (C2) in an amount of from 2 to 15% by weight based on the sum of components (C1) and (C2)

[0091] (ii) at least partially melting the composition (CB);

[0092] (iii) mixing the composition (CB) with a blowing agent, preferably in an amount of from 0.5 to 3.5 wt %, based on the weight of the composition (CB), to obtain a composition (CB*);

[0093] (iv) forming pellets of the composition (CB*);

[0094] (v) expanding the pellets to obtain the foamed pellets.

[0095] Preferably, the quantity of blowing agent to be employed is within the range between 0.5 and 3.5 wt % but may vary depending on the composition (CB) used and on the composition of the blowing agent.

[0096] Suitable inorganic gases are nitrogen, air, ammonia or carbon dioxide, preferably nitrogen or carbon dioxide, or mixtures of the above mentioned gases.

[0097] Carrying out the process via extrusion is known to those skilled in the art and has been described, by way of example, extensively in WC2007 / 082838, and also in WO 2013 / 153190 A1.

[0098] According to step (i), composition (CB) is provided. Composition (CB) may for example be prepared from the individual components by suitable processes known to the person skilled in the art.

[0099] In step (ii), composition (CB) is at least partially melted to allow mixing of the composition with a blowing agent according to step (iii). It is also possible to combine steps (i) and (ii), i.e.it is possible to provide the composition (CB) in form of a melt.

[0100] In step (iii) of the process, composition (CB) in form of a melt is mixed with a blowing agent and optionally with further adjuvants to obtain a composition (CB*). According to step (iv) pellets of the composition (CB*). Pellets may be formed by known methods, for example by pressing the composition through a perforated disc and using a suitable cutting device. The production of the polymer melt comprising blowing agent and, optionally, further adjuvants may preferably be accomplished in general by means of an extruder and / or a melt pump. These apparatuses are also utilized to generate the necessary pressure with which the polymer melt is pressed through the perforated disk. When using an extruder, a twin-screw extruder for example, the composition (CB) is first plasticized and optionally mixed with auxiliaries. During mixing, the material within the extruder is transported in the direction of the temperature-controlled perforated disk. If the blowing agent was not inserted into the extruder from the start, together with the polymer, it may be added to the material after the latter has traveled part of the distance in the extruder. The blowing agent and the polymer are mixed during travel over the remaining distance in the extruder. In this process, the melt is brought to the temperature required for the subsequent pelletization, preferably in the range of 150 to 200°C and preferably 170 to 190°C The pressure needed for pressing the melt through the perforated disk may be applied, for example, using a melt pump. Alternatively, the required pressure is generated by the corresponding geometry of the extruder and, in particular, of the extruder screw. The polymer melt passes through the temperature-controlled perforated disk and into the pelletizing chamber.

[0101] The pelletizing chamber preferably is traversed by a flow of a temperature-controlled liquid, the pressure of which is 0.1 bar to 20 bar above the ambient pressure. In the pelletizing chamber, the polymer forced through the temperature-controlled perforated disk is shaped into strands which a cutting device comminutes into individual expanding pellets. The cutting device may be embodied as a fast-rotating blade, for example. The shape of the resulting pellets is dependent on the shape and size of the openings in the perforated disk and also on the pressure at which the melt is forced through the holes in the perforated disk, and on the speed of the cutting device. It is preferable for the forcing pressure, the speed of the cutting device, and the size of the openings in the perforated disk to be chosen such that the shape of the pellets is substantially spherical or elliptical.

[0102] In the last step of the process, (v), the pellets are preferably discharged from the pelletizing chamber by the temperature-controlled water flowing through the pelletizing chamber. The choice of pressure and temperature for the water is such that the polymer strands / pellets are subjected to controlled expansion by the blowing agent they contain, and an uninterrupted and uniform skin is formed on the surface of the pellets.

[0103] In case underwater pelletization is carried out, in general at 5 to 90°C and preferably 30 to 80°C and a pressure of 0.1 to 20 bar above ambient pressure. Suitable methods and conditions for the process are in principle known to the person skilled in the art.

[0104] The conditions for the steps of the process, in particular of step (iv) of the process, may be adapted depending on the composition (CB) used in the process. In particular the temperature and pressure used may be adjusted in order to obtain stable foamed pellets. Suitable process conditions are in principle known to the person skilled in the art. According to a further embodiment, the present invention also relates to the process as disclosed above, wherein the pellets are formed by

[0105] (iv.1 ) pressing the melt through a perforated disk, preferably controlled to a temperature in the range of 150° C to 190° C, into a pelletizing chamber;

[0106] (iv.2) using a cutting device to comminute the polymer melt pressed through the perforated disk into individual expanding pellets,

[0107] (iv.3) discharging the pellets from the pelletizing chamber into a stream of water which preferably is at a temperature of 5 to 90° C. and a pressure of 0.1 bar to 20 bar above ambient pressure.

[0108] According to a further embodiment, the present invention also relates to the process as disclosed above, wherein in step (iv.1) the temperature of the perforated disk is controlled to a temperature in the range of 150° C to 190° C.

[0109] The present invention further provides a molded body produced from the inventive foamed pellets. The corresponding molded bodies can be produced by methods known to those skilled in the art.

[0110] For example, the foamed pellets can be adhesively bonded to one another in a discontinuous or continuous method by means of an adhesive bonding agent, using polyurethane adhesives known from the literature, for example.

[0111] Preferably, however, the foamed pellets are welded to one another under action of heat in a closed mold or by fusing the pellets using radiation. This is preferably done by filling the mold with the foamed pellets, then closing the mold and introducing steam or hot air, thereby causing further expansion of the foam beads and their fusing to one another to form foam, preferably with a density in the range from 8 to 300 kg / m3. The foams may be semi-finished products, such as slabs, profiles or sheets, for example, or finished parts with simple or complex geometries.

[0112] According to a further aspect, the present invention also relates to a process for preparing a molded body, comprising

[0113] (A) providing foamed pellets as disclosed above,

[0114] (B) fusing the foamed pellets.

[0115] The fusing in step (B) is preferably effected in a closed mold, wherein the fusing can be effected by means of steam, hot air (as described for example in EP1979401 B 1 ) or energetic radiation (microwaves or radio waves).

[0116] In one preferred embodiment the second step is implemented by fusing expanded foam beads to one another under the action of heat in a closed mold. This is done by filling the mold, preferably, with the foam beads and, after closing the mold, introducing steam or hot air, thereby causing further expansion of the foam beads and their fusing to one another to form the shaped component. Typically, the pressure is in the range of from 0.1 to 1.7 bar, preferably in a range of from 0.2 to 1 .6 bar, in particular in a range of from 0.3 to 1 .2 bar. The temperature during the fusing of the foamed pellets is preferably below or close to the melting temperature of the polymer from which the bead foam was produced. For the widely used polymers, the temperature for the fusing of the foamed pellets is accordingly between 100°C and 180°C, preferably between 120 and 150°C.

[0117] Temperature profiles / residence times can be ascertained individually here, for example in analogy to the processes described in US20150337102 or EP2872309B1.

[0118] The fusion by way of energetic radiation generally takes place in the frequency range of microwaves or radio waves, optionally in the presence of water or of other polar liquids, for example microwave-absorbing hydrocarbons having polar groups (such as for example esters of carboxylic acids and of diols or of triols, or glycols and liquid polyethylene glycols), and can be effected in analogy to the processes described in EP3053732A or WO16146537.

[0119] According to a further aspect, the present invention also relates to a molded body obtained according to the process as disclosed above.

[0120] As stated above, the inventive moldings have advantageous properties for the abovementioned applications in the shoe and sports shoe sector requirement.

[0121] The invention additionally provides for the use of inventive foamed pellets for the production of a molded body for shoe intermediate soles, shoe insoles, shoe combisoles, foot pads or calf pads, bicycle saddles, bicycle tires, damping elements, cushioning, mattresses, underlays, grips, protective films, in components in automobile interiors and exteriors, in balls and sports equipment or as floor covering, especially for sports surfaces, track and field surfaces, sports halls, children's playgrounds and pathways. The invention additionally provides for the use of inventive foamed pellets for the production of consumer goods or industrial goods, parts in the automotive sector or packaging.

[0122] Preference is given to using inventive foamed pellets for the production of a molded body for shoe intermediate soles, shoe insoles, shoe combisoles or a cushioning element for shoes. Here, the shoe is preferably an outdoor shoe, sports shoe, sandals, boot or safety shoe, particularly preferably a sports shoe.

[0123] According to the present invention, the molded body according to the present invention may also comprise further parts, in particular compact parts. The compact parts may comprise a polymer, in particular consist of a polymer, for example a polyester or polyurethane. The compact part may be preformed or it may be prepared after fusing the foamed pellets. Suitable methods for preparing compact parts are in principle known to the person skilled in the art.

[0124] According to a further embodiment, the present invention also relates to the molded body as disclosed above, where the molded body is an intermediate sole, an insole, an insert or a cushioning element for shoes, where the shoe is an outdoor shoe, sports shoe, sandal, boot or safety shoe, a bicycle saddle, bicycle tire, toy, packaging, protective wear, damping element, cushioning, mattress, underlay, grip, protective film, a component in the automobile-interior sector or automobile-exterior sector, ball or sports equipment, or a part of a floorcovering. According to a further embodiment, the present invention also relates to the molded body as disclosed above, where the molded body is an intermediate sole, an insole, an insert or a cushioning element for shoes, where the shoe is an outdoor shoe, sports shoe, sandal, boot or safety shoe.

[0125] The cushioning element here can by way of example be used in the heel region or forefoot region.

[0126] The present invention therefore also further provides a shoe in which the inventive molded body is used as midsole, insole, intermediate sole or cushioning in, for example, the heel region or forefoot region, wherein the shoe is preferably an outdoor shoe, sports shoe, sandal, boot or safety shoe, particularly preferably a sports shoe. According to a further aspect, the present invention also relates to a shoe comprising a molded body as disclosed above.

[0127] In a further aspect, the present invention also relates to the use of foamed pellets as disclosed above for the production of a molded body for shoe intermediate soles, shoe insoles, shoe combisoles, cushioning elements for shoes, bicycle saddles, bicycle tires, toys, packaging, protective wear, damping elements, cushioning, mattresses, underlays, grips, protective films, in components in the automobile-interior sector or automobile-exterior sector, balls and sports equipment, or as floorcovering.

[0128] The present invention is further illustrated by the following set of embodiments and combinations of embodiments resulting from the dependencies and back-references as indicated. In particular, it is noted that in each instance where a range of embodiments is mentioned, for example in the context of a term such as "The process of any one of embodiments 1 to 4", every embodiment in this range is meant to be explicitly disclosed for the skilled person, i.e. the wording of this term is to be understood by the skilled person as being synonymous to "The process of any one of embodiments 1, 2, 3 and 4". Further, it is explicitly noted that the following set of embodiments represents a suitably structured part of the general description directed to preferred aspects of the present invention, and, thus, suitably supports, but does not represent the claims of the present invention.

[0129] 1 . Foamed pellets comprising a composition (CB) comprising

[0130] (a) a first polymer selected from the group consisting of aliphatic-aromatic polyesters and aliphatic polyesters based on aliphatic dicarboxylic acids and aliphatic dihydroxyl compounds as component (C1) in an amount of from 85 to 99.9% by weight based on the sum of components (C1) and (C2);

[0131] (b) a second polymer which is different from the first polymer, and the second polymer is selected from the group consisting of aliphatic-aromatic polyesters, aliphatic polyesters based on aliphatic dicarboxylic acids and aliphatic dihydroxyl compounds, polycaprolactone (PCL), ester-based thermoplastic polyurethanes and polylactic acid (PLA) as component (C2) in an amount of from 0.1 to 12% by weight based on the sum of components (C1) and (C2). 2. The foamed pellets according to embodiment 1 , wherein the component (C1) is selected from poly(butylene sebacate-co-terephthalate (PBSeT) copolyesters.

[0132] 3. Foamed pellets comprising a composition (CB) comprising

[0133] (a) a first polymer selected from the group consisting of aliphatic-aromatic polyesters and aliphatic polyesters based on aliphatic dicarboxylic acids and aliphatic dihydroxyl compounds as component (C1) in an amount of from 85 to 99.9% by weight based on the sum of components (C1) and (C2); wherein the component (C1) is selected from poly(butylene sebacate-co-terephthalate (PBSeT) copolyesters;

[0134] (b) a second polymer which is different from the first polymer, and the second polymer is selected from the group consisting of aliphatic-aromatic polyesters, aliphatic polyesters based on aliphatic dicarboxylic acids and aliphatic dihydroxyl compounds, polycaprolactone (PCL), ester-based thermoplastic polyurethanes and polylactic acid (PLA) as component (C2) in an amount of from 0.1 to 12% by weight based on the sum of components (C1) and (C2).

[0135] 4. The foamed pellets according to any one of embodiments 1 to 3, wherein component (C1) is selected from poly (butylene sebacate-co-terephthalate (PBSeT) copolyesters with a molecular weight (Mw) of > 100 kg / mol, determined using GPC (HFIP, PMMA standard).

[0136] 5. Foamed pellets comprising a composition (CB) comprising

[0137] (a) a first polymer selected from the group consisting of aliphatic-aromatic polyesters and aliphatic polyesters based on aliphatic dicarboxylic acids and aliphatic dihydroxyl compounds as component (C1) in an amount of from 85 to 99.9% by weight based on the sum of components (C1) and (C2), wherein component (C1) is selected from poly (butylene sebacate-co-terephthalate (PBSeT) copolyesters with a molecular weight (Mw) of > 100 kg / mol, determined using GPC (HFIP, PMMA standard);

[0138] (b) a second polymer which is different from the first polymer, and the second polymer is selected from the group consisting of aliphatic-aromatic polyesters, aliphatic polyesters based on aliphatic dicarboxylic acids and aliphatic dihydroxyl compounds, polycaprolactone (PCL), ester-based thermoplastic polyurethanes and polylactic acid (PLA) as component (C2) in an amount of from 0.1 to 12% by weight based on the sum of components (C1) and (C2).

[0139] 6. The foamed pellets according to any one of embodiments 1 to 5, wherein component (C2) is selected from the group consisting of aliphatic-aromatic polyesters, aliphatic polyesters based on aliphatic dicarboxylic acids and aliphatic dihydroxyl compounds, polycaprolactone (PCL), and ester-based thermoplastic polyurethanes.

[0140] 7. Foamed pellets comprising a composition (CB) comprising

[0141] (a) a first polymer selected from the group consisting of aliphatic-aromatic polyesters and aliphatic polyesters based on aliphatic dicarboxylic acids and aliphatic dihydroxyl compounds as component (C1) in an amount of from 85 to 99.9% by weight based on the sum of components (C1) and (C2); wherein the component (C1) is selected from poly(butylene sebacate-co-terephthalate (PBSeT) copolyesters;

[0142] (b) a second polymer which is different from the first polymer, and the second polymer is selected from the group consisting of aliphatic-aromatic polyesters, aliphatic polyesters based on aliphatic dicarboxylic acids and aliphatic dihydroxyl compounds, polycaprolactone (PCL), ester-based thermoplastic polyurethanes and polylactic acid (PLA) as component (C2) in an amount of from 0.1 to 12% by weight based on the sum of components (C1) and (C2), wherein component (C2) is selected from the group consisting of aliphatic-aromatic polyesters, aliphatic polyesters based on aliphatic dicarboxylic acids and aliphatic dihydroxyl compounds, polycaprolactone (PCL), and ester-based thermoplastic polyurethanes.

[0143] 8. Foamed pellets comprising a composition (CB) comprising

[0144] (a) a first polymer selected from the group consisting of aliphatic-aromatic polyesters and aliphatic polyesters based on aliphatic dicarboxylic acids and aliphatic dihydroxyl compounds as component (C1) in an amount of from 85 to 99.9% by weight based on the sum of components (C1) and (C2), wherein component (C1) is selected from poly (butylene sebacate-co-terephthalate (PBSeT) copolyesters with a molecular weight (Mw) of > 100 kg / mol, determined using GPC (HFIP, PMMA standard);

[0145] (b) a second polymer which is different from the first polymer, and the second polymer is selected from the group consisting of aliphatic-aromatic polyesters, aliphatic polyesters based on aliphatic dicarboxylic acids and aliphatic dihydroxyl compounds, polycaprolactone (PCL), ester-based thermoplastic polyurethanes and polylactic acid (PLA) as component (C2) in an amount of from 0.1 to 12% by weight based on the sum of components (C1) and (C2), wherein component (C2) is selected from the group consisting of aliphatic-aromatic polyesters, aliphatic polyesters based on aliphatic dicarboxylic acids and aliphatic dihydroxyl compounds, polycaprolactone (PCL), and ester-based thermoplastic polyurethanes.

[0146] 9. The foamed pellets according to any one of embodiments 1 to 8, wherein the component (C2) is selected from polybutylene succinate (PBS) and polylactic acid (PLA), preferably from polybutylene succinate (PBS).

[0147] 10. Foamed pellets comprising a composition (CB) comprising

[0148] (a) a first polymer selected from the group consisting of aliphatic-aromatic polyesters and aliphatic polyesters based on aliphatic dicarboxylic acids and aliphatic dihydroxyl compounds as component (C1) in an amount of from 85 to 99.9% by weight based on the sum of components (C1) and (C2); wherein the component (C1) is selected from poly(butylene sebacate-co-terephthalate (PBSeT) copolyesters;

[0149] (b) a second polymer which is different from the first polymer, and the second polymer is selected from the group consisting of aliphatic-aromatic polyesters, aliphatic polyesters based on aliphatic dicarboxylic acids and aliphatic dihydroxyl compounds, polycaprolactone (PCL), ester-based thermoplastic polyurethanes and polylactic acid (PLA) as component (C2) in an amount of from 0.1 to 12% by weight based on the sum of components (C1) and (C2), wherein the component (C2) is selected from polybutylene succinate (PBS) and polylactic acid (PLA), preferably from polybutylene succinate (PBS). 11 . Foamed pellets comprising a composition (CB) comprising

[0150] (a) a first polymer selected from the group consisting of aliphatic-aromatic polyesters and aliphatic polyesters based on aliphatic dicarboxylic acids and aliphatic dihydroxyl compounds as component (C1) in an amount of from 85 to 99.9% by weight based on the sum of components (C1) and (C2), wherein component (C1) is selected from poly (butylene sebacate-co-terephthalate (PBSeT) copolyesters with a molecular weight (Mw) of > 100 kg / mol, determined using GPC (HFIP, PMMA standard);

[0151] (b) a second polymer which is different from the first polymer, and the second polymer is selected from the group consisting of aliphatic-aromatic polyesters, aliphatic polyesters based on aliphatic dicarboxylic acids and aliphatic dihydroxyl compounds, polycaprolactone (PCL), ester-based thermoplastic polyurethanes and polylactic acid (PLA) as component (C2) in an amount of from 0.1 to 12% by weight based on the sum of components (C1) and (C2), wherein the component (C2) is selected from polybutylene succinate (PBS) and polylactic acid (PLA), preferably from polybutylene succinate (PBS).

[0152] 12. The foamed pellets according to any one of embodiments 1 to 11 , wherein the component (C1) or the component (C2) or the component (C1) and the component (C2) are biobased polymers.

[0153] 13. The foamed pellets according to any one of embodiments 1 to 12, where the average diameter of the foamed pellets is in the range of from 0.2 to 20 mm.

[0154] 14. The foamed pellets according to any one of embodiments 1 to 13, where the average mass of the foamed pellets is in the range of from 1 to 40 mg.

[0155] 15. A process for preparing foamed pellets, the process comprising

[0156] (i) providing the composition (CB);

[0157] (ii) at least partially melting the composition (CB);

[0158] (iii) mixing the composition (CB) with a blowing agent, preferably in an amount of from 0.5 to 3.5 wt %, based on the weight of the composition (CB), to obtain a composition (CB*);

[0159] (iv) forming pellets of the composition (CB*);

[0160] (v) expanding the pellets to obtain the foamed pellets.

[0161] 16. A process for preparing foamed pellets, the process comprising

[0162] (i) providing the composition (CB);

[0163] (ii) at least partially melting the composition (CB);

[0164] (iii) mixing the composition (CB) with a blowing agent, preferably in an amount of from 0.5 to 3.5 wt %, based on the weight of the composition (CB), to obtain a composition (CB*);

[0165] (iv) forming pellets of the composition (CB*);

[0166] (v) expanding the pellets to obtain the foamed pellets; composition (CB) comprising

[0167] (a) a first polymer selected from the group consisting of aliphatic-aromatic polyesters and aliphatic polyesters based on aliphatic dicarboxylic acids and aliphatic dihydroxyl compounds as component (C1) in an amount of from 85 to 99.9% by weight based on the sum of components (C1) and (C2);

[0168] (b) a second polymer which is different from the first polymer, and the second polymer is selected from the group consisting of aliphatic-aromatic polyesters, aliphatic polyesters based on aliphatic dicarboxylic acids and aliphatic dihydroxyl compounds, polycaprolactone (PCL), ester-based thermoplastic polyurethanes and polylactic acid (PLA) as component (C2) in an amount of from 0.1 to 12% by weight based on the sum of components (C1) and (C2).

[0169] 17. The process according to embodiment 15 or 16, wherein the pellets are formed by

[0170] (iv.1 ) pressing the melt through a perforated disk, preferably controlled to a temperature in the range of 150° C to 200° C, into a pelletizing chamber;

[0171] (iv.2) using a cutting device to comminute the polymer melt pressed through the perforated disk into individual expanding pellets;

[0172] (iv.3) discharging the pellets from the pelletizing chamber into a stream of water which preferably is at a temperature of 5 to 90° C and a pressure of 0.1 bar to 20 bar above ambient pressure.

[0173] 18. The process according to embodiment 17, wherein in step (iv.1 ) the temperature of the perforated disk is controlled to a temperature in the range of 150° C to 190° C.

[0174] 19. The process according to any one of embodiments 16 to 18, wherein the component (C1) is selected from poly (butylene sebacate-co-terephthalate (PBSeT) copolyesters.

[0175] 20. The process according to any one of embodiments 16 to 19, wherein component (C1) is selected from poly (butylene sebacate-co-terephthalate (PBSeT) copolyesters with a molecular weight (Mw) of > 100 kg / mol, determined using GPC (HFIP, PMMA standard).

[0176] 21 . The process according to any one of embodiments 16 to 20, wherein component (C2) is selected from the group consisting of aliphatic-aromatic polyesters, aliphatic polyesters based on aliphatic dicarboxylic acids and aliphatic dihydroxyl compounds, polycaprolactone (PCL), and ester-based thermoplastic polyurethanes.

[0177] 22. The process according to any one of embodiments 16 to 21, wherein the component (C2) is selected from polybutylene succinate (PBS) and polylactic acid (PLA), preferably from polybutylene succinate (PBS).

[0178] 23. The process according to any one of embodiments 16 to 22, wherein the component (C1) or the component (C2) or the component (C1) and the component (C2) are biobased polymers. 24. The process according to any one of embodiments 16 to 23, where the average diameter of the foamed pellets is in the range of from 0.2 to 20 mm and / or where the average mass of the foamed pellets is in the range of from 1 to 40 mg.

[0179] 25. A process for preparing a molded body, comprising

[0180] (A) providing foamed pellets according to any one of embodiments 1 to 14;

[0181] (B) fusing the foamed pellets.

[0182] 26. A process for preparing a molded body, comprising

[0183] (A) providing foamed pellets obtained according a process according to any one of embodiments 15 to 25;

[0184] (B) fusing the foamed pellets.

[0185] 27. A molded body obtained according to the process of embodiment 25 or 26.

[0186] 28. The molded body according to embodiment 27, where the molded body is an intermediate sole, an insole, an insert or a cushioning element for shoes, where the shoe is an outdoor shoe, sports shoe, sandal, boot or safety shoe, a bicycle saddle, bicycle tire, toy, packaging, protective wear, foot pad, calf pad, damping element, cushioning, mattress, underlay, grip, protective film, a component in the automobile-interior sector or automobile-exterior sector, ball or sports equipment, or a part of a floorcovering.

[0187] 29. A shoe comprising a molded body according to any of embodiments 27 or 28.

[0188] 30. The use of foamed pellets according to any of embodiments 1 to 14 or foamed pellets obtained according a process according to any one of embodiments 15 to 25 for the production of a molded body for shoe intermediate soles, shoe insoles, shoe combisoles, cushioning elements for shoes, bicycle saddles, bicycle tires, toys, packaging, protective wear, damping elements, cushioning, mattresses, underlays, grips, protective films, in components in the automobile-interior sector or automobile-exterior sector, balls and sports equipment, or as floorcovering.

[0189] 31 . The use according to embodiment 30, wherein the molded body further comprises at least one compact part comprising a polyester.

[0190] 32. Foamed pellets comprising a composition (CB) comprising

[0191] (a) a first polymer selected from the group consisting of aliphatic-aromatic polyesters and aliphatic polyesters as component (C1) in an amount of from 85 to 99.9% by weight based on the sum of components (C1) and (C2); (b) a second polymer which is different from the first polymer, and the second polymer is selected from the group consisting of aliphatic-aromatic polyesters, aliphatic polyesters, polycaprolactone (PCL), ester- based thermoplastic polyurethanes and polylactic acid (PLA) as component (C2) in an amount of from 0.1 to 15% by weight based on the sum of components (C1) and (C2). The foamed pellets according to embodiment 32, wherein the component (C1) is selected from poly(butylene sebacate-co-terephthalate (PBSeT) copolyesters. Foamed pellets comprising a composition (CB) comprising

[0192] (a) a first polymer selected from the group consisting of aliphatic-aromatic polyesters and aliphatic polyesters as component (C1) in an amount of from 85 to 99.9% by weight based on the sum of components (C1) and (C2); wherein the component (C1) is selected from poly(butylene sebacate-co-terephthalate (PBSeT) copolyesters;

[0193] (b) a second polymer which is different from the first polymer, and the second polymer is selected from the group consisting of aliphatic-aromatic polyesters, aliphatic polyesters, polycaprolactone (PCL), ester- based thermoplastic polyurethanes and polylactic acid (PLA) as component (C2) in an amount of from 0.1 to 15% by weight based on the sum of components (C1) and (C2). The foamed pellets according to any one of embodiments 32 to 34, wherein component (C1) is selected from poly (butylene sebacate-co-terephthalate (PBSeT) copolyesters with a molecular weight (Mw) of > 100 kg / mol, determined using GPC (HFIP, PMMA standard). Foamed pellets comprising a composition (CB) comprising

[0194] (a) a first polymer selected from the group consisting of aliphatic-aromatic polyesters and aliphatic polyesters as component (C1) in an amount of from 85 to 99.9% by weight based on the sum of components (C1) and (C2), wherein component (C1) is selected from poly(butylene sebacate-co-terephthalate (PBSeT) copolyesters with a molecular weight (Mw) of > 100 kg / mol, determined using GPC (HFIP, PMMA standard);

[0195] (b) a second polymer which is different from the first polymer, and the second polymer is selected from the group consisting of aliphatic-aromatic polyesters, aliphatic polyesters, polycaprolactone (PCL), ester- based thermoplastic polyurethanes and polylactic acid (PLA) as component (C2) in an amount of from 0.1 to 15% by weight based on the sum of components (C1) and (C2). The foamed pellets according to any one of embodiments 32 to 36, wherein component (C2) is selected from the group consisting of aliphatic-aromatic polyesters, aliphatic polyesters, polycaprolactone (PCL), and ester- based thermoplastic polyurethanes. Foamed pellets comprising a composition (CB) comprising (a) a first polymer selected from the group consisting of aliphatic-aromatic polyesters and aliphatic polyesters as component (C1) in an amount of from 85 to 99.9% by weight based on the sum of components (C1) and (C2); wherein the component (C1) is selected from poly(butylene sebacate-co-terephthalate (PBSeT) copolyesters;

[0196] (b) a second polymer which is different from the first polymer, and the second polymer is selected from the group consisting of aliphatic-aromatic polyesters, aliphatic polyesters, polycaprolactone (PCL), ester- based thermoplastic polyurethanes and polylactic acid (PLA) as component (C2) in an amount of from 0.1 to 15% by weight based on the sum of components (C1) and (C2), wherein component (C2) is selected from the group consisting of aliphatic-aromatic polyesters, aliphatic polyesters, polycaprolactone (PCL), and ester-based thermoplastic polyurethanes.

[0197] 39. Foamed pellets comprising a composition (CB) comprising

[0198] (a) a first polymer selected from the group consisting of aliphatic-aromatic polyesters and aliphatic polyesters as component (C1) in an amount of from 85 to 99.9% by weight based on the sum of components (C1) and (C2), wherein component (C1) is selected from poly(butylene sebacate-co-terephthalate (PBSeT) copolyesters with a molecular weight (Mw) of > 100 kg / mol, determined using GPC (HFIP, PMMA standard);

[0199] (b) a second polymer which is different from the first polymer, and the second polymer is selected from the group consisting of aliphatic-aromatic polyesters, aliphatic polyesters, polycaprolactone (PCL), ester- based thermoplastic polyurethanes and polylactic acid (PLA) as component (C2) in an amount of from 0.1 to 15% by weight based on the sum of components (C1) and (C2), wherein component (C2) is selected from the group consisting of aliphatic-aromatic polyesters, aliphatic polyesters, polycaprolactone (PCL), and ester-based thermoplastic polyurethanes.

[0200] 40. The foamed pellets according to any one of embodiments 32 to 39, wherein the component (C2) is selected from polybutylene succinate (PBS) and polylactic acid (PLA), preferably from polybutylene succinate (PBS).

[0201] 41 . Foamed pellets comprising a composition (CB) comprising

[0202] (a) a first polymer selected from the group consisting of aliphatic-aromatic polyesters and aliphatic polyesters as component (C1) in an amount of from 85 to 99.9% by weight based on the sum of components (C1) and (C2); wherein the component (C1) is selected from poly(butylene sebacate-co-terephthalate (PBSeT) copolyesters;

[0203] (b) a second polymer which is different from the first polymer, and the second polymer is selected from the group consisting of aliphatic-aromatic polyesters, aliphatic polyesters, polycaprolactone (PCL), ester- based thermoplastic polyurethanes and polylactic acid (PLA) as component (C2) in an amount of from 0.1 to 15% by weight based on the sum of components (C1) and (C2), wherein the component (C2) is selected from polybutylene succinate (PBS) and polylactic acid (PLA), preferably from polybutylene succinate (PBS). 42. Foamed pellets comprising a composition (CB) comprising

[0204] (a) a first polymer selected from the group consisting of aliphatic-aromatic polyesters and aliphatic polyesters as component (C1) in an amount of from 85 to 99.9% by weight based on the sum of components (C1) and (C2), wherein component (C1) is selected from poly(butylene sebacate-co-terephthalate (PBSeT) copolyesters with a molecular weight (Mw) of > 100 kg / mol, determined using GPC (HFIP, PMMA standard);

[0205] (b) a second polymer which is different from the first polymer, and the second polymer is selected from the group consisting of aliphatic-aromatic polyesters, aliphatic polyesters, polycaprolactone (PCL), ester- based thermoplastic polyurethanes and polylactic acid (PLA) as component (C2) in an amount of from 0.1 to 15% by weight based on the sum of components (C1) and (C2), wherein the component (C2) is selected from polybutylene succinate (PBS) and polylactic acid (PLA), preferably from polybutylene succinate (PBS).

[0206] 43. The foamed pellets according to any one of embodiments 32 to 42, wherein the component (C1) or the component (C2) or the component (C1) and the component (C2) are biobased polymers.

[0207] 44. The foamed pellets according to any one of embodiments 32 to 43, where the average diameter of the foamed pellets is in the range of from 0.2 to 20 mm.

[0208] 45. The foamed pellets according to any one of embodiments 32 to 44, where the average mass of the foamed pellets is in the range of from 1 to 40 mg.

[0209] 46. A process for preparing foamed pellets, the process comprising

[0210] (i) providing the composition (CB);

[0211] (ii) at least partially melting the composition (CB);

[0212] (iii) mixing the composition (CB) with a blowing agent, preferably in an amount of from 0.5 to 3.5 wt %, based on the weight of the composition (CB), to obtain a composition (CB*);

[0213] (iv) forming pellets of the composition (CB*);

[0214] (v) expanding the pellets to obtain the foamed pellets.

[0215] 47. A process for preparing foamed pellets, the process comprising

[0216] (i) providing the composition (CB);

[0217] (ii) at least partially melting the composition (CB);

[0218] (iii) mixing the composition (CB) with a blowing agent, preferably in an amount of from 0.5 to 3.5 wt %, based on the weight of the composition (CB), to obtain a composition (CB*);

[0219] (iv) forming pellets of the composition (CB*);

[0220] (v) expanding the pellets to obtain the foamed pellets; composition (CB) comprising

[0221] (a) a first polymer selected from the group consisting of aliphatic-aromatic polyesters and aliphatic polyesters as component (C1) in an amount of from 85 to 99.9% by weight based on the sum of components (C1) and (C2);

[0222] (b) a second polymer which is different from the first polymer, and the second polymer is selected from the group consisting of aliphatic-aromatic polyesters, aliphatic polyesters, polycaprolactone (PCL), ester- based thermoplastic polyurethanes and polylactic acid (PLA) as component (C2) in an amount of from 0.1 to 15% by weight based on the sum of components (C1) and (C2).

[0223] 48. The process according to embodiment 46 or 47, wherein the pellets are formed by

[0224] (iv.1 ) pressing the melt through a perforated disk, preferably controlled to a temperature in the range of 150° C to 200° C, into a pelletizing chamber;

[0225] (iv.2) using a cutting device to comminute the polymer melt pressed through the perforated disk into individual expanding pellets;

[0226] (iv.3) discharging the pellets from the pelletizing chamber into a stream of water which preferably is at a temperature of 5 to 90° C and a pressure of 0.1 bar to 20 bar above ambient pressure.

[0227] 49. The process according to embodiment 48, wherein in step (iv.1 ) the temperature of the perforated disk is controlled to a temperature in the range of 150° C to 190° C.

[0228] 50. The process according to any one of embodiments 46 to 49, wherein the component (C1) is selected from poly (butylene sebacate-co-terephthalate (PBSeT) copolyesters.

[0229] 51 . The process according to any one of embodiments 46 to 50, wherein component (C1) is selected from poly (butylene sebacate-co-terephthalate (PBSeT) copolyesters with a molecular weight (Mw) of > 100 kg / mol, determined using GPC (HFIP, PMMA standard).

[0230] 52. The process according to any one of embodiments 46 to 51 , wherein component (C2) is selected from the group consisting of aliphatic-aromatic polyesters, aliphatic polyesters, polycaprolactone (PCL), and ester- based thermoplastic polyurethanes.

[0231] 53. The process according to any one of embodiments 46 to 52, wherein the component (C2) is selected from polybutylene succinate (PBS) and polylactic acid (PLA), preferably from polybutylene succinate (PBS).

[0232] 54. The process according to any one of embodiments 46 to 53, wherein the component (C1) or the component (C2) or the component (C1) and the component (C2) are biobased polymers. 55. The process according to any one of embodiments 46 to 54, where the average diameter of the foamed pellets is in the range of from 0.2 to 20 mm.

[0233] 56. The process according to any one of embodiments 46 to 55, where the average mass of the foamed pellets is in the range of from 1 to 40 mg.

[0234] 57. A process for preparing a molded body, comprising

[0235] (A) providing foamed pellets according to any one of embodiments 32 to 45;

[0236] (B) fusing the foamed pellets.

[0237] 58. A process for preparing a molded body, comprising

[0238] (A) providing foamed pellets obtained according a process according to any one of embodiments 46 to 56;

[0239] (B) fusing the foamed pellets.

[0240] 59. A molded body obtained according to the process of embodiment 57 or 58.

[0241] 60. The molded body according to embodiment 59, where the molded body is an intermediate sole, an insole, an insert or a cushioning element for shoes, where the shoe is an outdoor shoe, sports shoe, sandal, boot or safety shoe, a bicycle saddle, bicycle tire, toy, packaging, protective wear, foot pad, calf pad, damping element, cushioning, mattress, underlay, grip, protective film, a component in the automobile-interior sector or automobile-exterior sector, ball or sports equipment, or a part of a floorcovering.

[0242] 61 . A shoe comprising a molded body according to any of embodiments 59 or 60.

[0243] 62. The use of foamed pellets according to any of embodiments 32 to 45 or foamed pellets obtained according a process according to any one of embodiments 46 to 56 for the production of a molded body for shoe intermediate soles, shoe insoles, shoe combisoles, cushioning elements for shoes, bicycle saddles, bicycle tires, toys, packaging, protective wear, damping elements, cushioning, mattresses, underlays, grips, protective films, in components in the automobile-interior sector or automobile-exterior sector, balls and sports equipment, or as floorcovering.

[0244] 63. The use according to embodiment 62, wherein the molded body further comprises at least one compact part comprising a polyester.

[0245] The present invention is further illustrated by the following examples.

[0246] Examples 1. Materials used

[0247] TPU1 thermoplastic polyurethane based on MDI, butanediol, Polytetrahydrofuran Mn=1000g / mol having a Shore hardness of 80A

[0248] PE1 polybutylene adipate terephthalate with a molecular weight Mw of 120 kg / mol, determined using GPC (HFIP, PMMA standard)

[0249] PE2 poly (butylene sebacate-co-terephthalate (PBSeT) copolyesters with a molecular weight Mw in the range of 100 to 150 kg / mol

[0250] PE3 polybutylene succinate with a molecular weight Mw>100 kg / mol

[0251] PLA polylactic acid with a molecular weight Mw= 191,063 g / mol, and a polydispersity index of 1.63, commercially available from Natureworks (Ingeo 4060D)

[0252] 2. Preparation of the foamed pellets

[0253] In a twin-screw extruder having a screw diameter of 44 mm and a length to diameter ratio of 42, dried pellet material mixture of the components (Table 1) were mixed and melted.

[0254] Table 1 : composition of the blends and reference materials

[0255] After melting, a mixture of CO2 (1 .2 parts by weight) and N2 (0.15 parts by weight) was added as blowing agent. While passing along the rest of the extruder length, the blowing agent and the polymer melt were mixed with each other, resulting in the formation of a homogeneous mixture. The total throughput of the extruder comprising the polymers and the blowing agents was 40 kg / h.

[0256] The melt mixture was then forced using a gear pump (GP) via a start-up valve with screen changer (SV) into a die plate (DP), cut into pellets (27 mg) in the cutting chamber of the underwater pelletization system (UWP), and transported away with the temperature-controlled and pressurized water and undergoing expansion in the process. After separating the expanded pellets from the water by means of a centrifugal dryer, the expanded pellets are dried at 60°C for 2 hours.

[0257] 3. Production of the shaped bodies

[0258] The expanded pellets were then fused in a molding machine from Kurtz ersa GmbH (Energy Foamer) to give square slabs having a side length of 200 mm and a thickness of 20 mm by contacting with water vapor. The fusion parameters of the different materials were chosen such that the slab side of the final shaped article that faced the movable side (M2) of the mold had a minimum number of collapsed particles. Achieving a satisfactory surface finish in the case of the comparative examples was not always possible. Regardless of the experiment, a cooling time of 120 s for a slab thickness of 20 mm from the fixed side (M1) and the movable side of the mold was always established at the end.

[0259] Table 2a and 2b list the respective steaming conditions as vapor pressures.

[0260] Table 2a: preparation of the molded bodies. Table 2b: preparation of the molded bodies.

[0261] 4. Properties of the foamed pellets / molded bodies The resulting properties of the expanded pellets for the individual blends and of the molded bodies are listed in Table 3.

[0262] Table 3: properties of the foamed pellets / molded bodies. According to table 3, it becomes clear that the inventive blends, compared to the reference materials, have advantages in the production of the molded bodies with respect to 30-60% lower equipment temperatures and 24% shorter cycle times (Table 2) and improved properties (Table 3).

[0263] 5. Measurement methods I DIN standards

[0264] Bulk density DIN EN ISO 845

[0265] Shore hardness DIN ISO 7619-1 (3s)

[0266] Rebound resilience / rebound DIN 53512

[0267] Shrinkage of the molded plates ISO 2796

[0268] Biodegradability DIN EN 13432 (2000-12)

[0269] Density of 20 mm foam plates ISO 2796

[0270] Literature cited

[0271] WO 94 / 20568 A1

[0272] WO 2007 / 082838 A1

[0273] WO2017 / 030835

[0274] WO 2013 / 153190 A1

[0275] WO2010 / 010010 A1

[0276] CN110172138

[0277] Guoqun Zhao et al. (Journal of CO2 Utilization 64 (2022) 102149 and Journal of CO2 Utilization 72 (2023) 102495)

[0278] WO 2018 / 029040

[0279] WO 2015 / 052020

[0280] WO 2014 / 198779

[0281] US 20150337102

[0282] EP 2872309 B1

[0283] EP 3053732 A

[0284] WO 2016 / 146537

Claims

1. Claims1 . Foamed pellets comprising a composition (CB) comprising(a) a first polymer selected from the group consisting of aliphatic-aromatic polyesters and aliphatic polyesters based on aliphatic dicarboxylic acids and aliphatic dihydroxyl compounds as component (C1) in an amount of from 85 to 99.9% by weight based on the sum of components (C1) and (C2);(b) a second polymer which is different from the first polymer, and the second polymer is selected from the group consisting of aliphatic-aromatic polyesters, aliphatic polyesters based on aliphatic dicarboxylic acids and aliphatic dihydroxyl compounds, polycaprolactone (PCL), ester-based thermoplastic polyurethanes and polylactic acid (PLA) as component (C2) in an amount of from 0.1 to 12% by weight based on the sum of components (C1) and (C2).

2. The foamed pellets according to claim 1, wherein the component (C1) is selected from poly(butylene sebacate- co-terephthalate (PBSeT) copolyesters.

3. The foamed pellets according to any one of claims 1 to 2, wherein component (C1) is selected from poly (butylene sebacate-co-terephthalate (PBSeT) copolyesters with a molecular weight (Mw) of > 100 kg / mol, determined using GPC (HFIP, PMMA standard).

4. The foamed pellets according to any one of claims 1 to 3, wherein component (C2) is selected from the group consisting of aliphatic-aromatic polyesters, aliphatic polyesters based on aliphatic dicarboxylic acids and aliphatic dihydroxyl compounds, polycaprolactone (PCL), and ester-based thermoplastic polyurethanes.

5. The foamed pellets according to any one of claims 1 to 4, wherein the component (C2) is selected from polybutylene succinate (PBS) and polylactic acid (PLA), preferably from polybutylene succinate (PBS).

6. The foamed pellets according to any one of claims 1 to 5, wherein the component (C1) or the component (C2) or the component (C1) and the component (C2) are biobased polymers.

7. The foamed pellets according to any one of claims 1 to 6, where the average diameter of the foamed pellets is in the range of from 0.2 to 20 mm.

8. The foamed pellets according to any one of claims 1 to 7, where the average mass of the foamed pellets is in the range of from 1 to 40 mg.

9. A process for preparing foamed pellets, the process comprising(i) providing the composition (CB);(ii) at least partially melting the composition (CB);(ill) mixing the composition (CB) with a blowing agent, preferably in an amount of from 0.5 to 3.5 wt %, based on the weight of the composition (CB), to obtain a composition (CB*);(iv) forming pellets of the composition (CB*);(v) expanding the pellets to obtain the foamed pellets.

10. The process according to claim 9, wherein the pellets are formed by(iv.1 ) pressing the melt through a perforated disk, preferably controlled to a temperature in the range of 150° C to 200° C, into a pelletizing chamber;(iv.2) using a cutting device to comminute the polymer melt pressed through the perforated disk into individual expanding pellets;(iv.3) discharging the pellets from the pelletizing chamber into a stream of water which preferably is at a temperature of 5 to 90° C. and a pressure of 0.1 bar to 20 bar above ambient pressure.11 . The process according to claim 10, wherein in step (iv.1 ) the temperature of the perforated disk is controlled to a temperature in the range of 150° C to 190° C.

12. A process for preparing a molded body, comprising(A) providing foamed pellets according to any one of claims 1 to 8;(B) fusing the foamed pellets.

13. A molded body obtained according to the process of claim 12.

14. The molded body according to claim 13, where the molded body is an intermediate sole, an insole, an insert or a cushioning element for shoes, where the shoe is an outdoor shoe, sports shoe, sandal, boot or safety shoe, a bicycle saddle, bicycle tire, toy, packaging, protective wear, foot pad, calf pad, damping element, cushioning, mattress, underlay, grip, protective film, a component in the automobile-interior sector or automobile-exterior sector, ball or sports equipment, or a part of a floorcovering.

15. A shoe comprising a molded body according to any of claims 13 or 14.

16. The use of foamed pellets according to any of claims 1 to 8 for the production of a molded body for shoe intermediate soles, shoe insoles, shoe combisoles, cushioning elements for shoes, bicycle saddles, bicycle tires, toys, packaging, protective wear, damping elements, cushioning, mattresses, underlays, grips, protective films, in components in the automobile-interior sector or automobile-exterior sector, balls and sports equipment, or as floorcovering.

17. The use according to claim 16, wherein the molded body further comprises at least one compact part comprising a polyester.

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