Thermoplastic polymer blends and uses thereof

Abstract

The present invention relates to a thermoplastic polymer blend comprising (a) as component (a) at least one thermoplastic hydrophobically modified starch, (b) as component (b) at least one thermoplastic natural starch, and (c) as component (c) at least one thermoplastic polyester, the at least one thermoplastic polyester is selected from the group consisting of aliphatic polyesters, aliphatic-aromatic polyesters, and mixtures thereof. The invention also relates to a method for preparing such a thermoplastic polymer blend, and to a single-layer or multi-layer film comprising at least one layer made of a thermoplastic polymer blend.

Description

[0001] manual

[0002] The present invention relates to a thermoplastic polymer blend comprising a thermoplastic polyester of the group of aliphatic polyesters and aliphatic-aromatic polyesters and thermoplastic starch. The present invention also relates to a process for preparing such a thermoplastic polymer blend, and a monolayer or multilayer film comprising at least one layer made of the thermoplastic polymer blend. Background Art

[0003] The use of thermoplastic materials such as polystyrene, polyethylene and polyurethane has long been established in many technical fields. However, these conventional thermoplastic materials are facing increasing criticism due to environmental reasons.

[0004] Starch is an important natural polymer that is increasingly being considered as an alternative to conventional plastics due to its biodegradability and other environmentally beneficial properties as well as its good availability.

[0005] Starch can be processed into so-called "thermoplastic starch (TPS)" using conventional polymer processing techniques such as extrusion, injection molding and compression molding with water and a plasticizer such as glycerol. However, materials based on native starch generally have poor processability, mechanical properties and stability. Therefore, modified starches, such as hydroxypropyl starch, are used to replace native starch. It is also known to blend native starch with other biodegradable polymers such as polycaprolactone. Such blends are commercially available, for example PLANTIC TM HP and Mater- .

[0006] Thermoplastic starches have been known for many years and various methods for their preparation are described in the literature, for example in US Pat. No. 5,362,777, WO 99 / 61524, DE 198 24 968 A1, WO 2012 / 162085 A1 or WO 2006 / 042364 A1. Thermoplastic starches are prepared from starch by plasticizing the starch with suitable plasticizers, usually polyols.

[0007] However, despite the addition of plasticizers, TPS is inherently brittle and hydrophilic. When TPS is used, it is difficult to meet high requirements for industrial products, such as mechanical strength and water resistance, especially in film extrusion.

[0008] When blending TPS with other thermoplastic polymers such as polyesters, one faces the problem that TPS has a very high melt viscosity, while other polymers tend to have significantly lower melt viscosities. Due to this difference in melt viscosity, fine dispersion of TPS in the polymer matrix is ​​difficult to achieve, and effective blending under high shear is required. This may result in mechanical damage to the TPS phase. In addition, the high melt viscosity of TPS makes processing more difficult, which is reflected in the increased torque and pressure conditions in the extruder.

[0009] Furthermore, the compatibility of hydrophilic TPS with hydrophobic polymers is limited. This leads to impairment of mechanical material properties, such as low tensile strength and elongation, as well as impairment of the final product appearance, which is manifested in part by a reduction in transparency and an increase in opacity. Various publications relate to the above-mentioned problems of starch blends containing TPS, such as the opacity problem when TPS is blended with other biopolymer compounds.

[0010] WO2022 / 157380 describes polymer compositions containing 25.5% by weight of native starch, including pea starch, and 30% to 74.5% by weight of thermoplastic aliphatic-aromatic copolyesters. The mechanical properties of the blends are not satisfactory.

[0011] CN112724472 discloses a polymer blend with a high starch content containing starch, a starch modifier, a compatibilizer, a plasticizer, a starch modifier and an inorganic filler. The mechanical properties of the blend are not satisfactory.

[0012] WO2019138022A1 and WO2020136231A1 describe the production of hydrophobically modified thermoplastic starch, including extruding a mixture of native starch, polyols (e.g., sorbitol), epoxides selected from the group of epoxidized vegetable oils, and carboxylic acids (e.g., citric acid). Also mentioned are blends of the hydrophobically modified TPS thus obtained and conventional polymers such as aliphatic-aromatic polyesters, such as poly(butylene adipate-co-terephthalate) (PBAT). The blend thus obtained contains a large amount of hydrophobically modified starch, and is therefore very expensive. Summary of the invention

[0013] However, there is still a need to overcome the above disadvantages and improve the properties, especially the mechanical properties, of thermoplastic polymer blends based on combinations of aliphatic or aliphatic-aromatic polyesters and TPS and products based thereon. At the same time, the polymer blends should be easy to process into thermoplastic polymer compounds and thermoplastic polymer films, especially in extrusion processing and blow molding or flat film extrusion.

[0014] It is therefore an object of the present invention to provide thermoplastic polymer blends based on a combination of aliphatic or aliphatic-aromatic polyesters and TPS which have good or even improved mechanical properties and impart these properties to the final product. At the same time, the thermoplastic polymer blends should be suitable for efficient processing into thermoplastic polymer compounds and thermoplastic polymer films, especially in extrusion processing and blow molding or flat film extrusion.

[0015] Surprisingly, it was found that the combination of hydrophobically modified TPS and TPS based on natural starch was blended with one or more polyesters selected from the group of aliphatic and aliphatic-aromatic polyesters to produce blends with good or even improved mechanical properties. In particular, expensive hydrophobically modified TPS can be partially replaced by cheaper TPS based on natural starch. Therefore, less hydrophobically modified TPS is required to obtain good product properties. In addition, the presence of a combination of hydrophobically modified TPS and TPS based on natural starch allows the production of blends containing large amounts of polyhydroxyalkanoates (PHA) without conferring the properties of the blown films prepared therefrom and the processing efficiency in film blowing.

[0016] Therefore, the present invention relates to a thermoplastic polymer blend comprising

[0017] (a) as component (a) at least one thermoplastic hydrophobically modified starch,

[0018] (b) at least one thermoplastic natural starch as component (b), and

[0019] (c) at least one thermoplastic polyester as component (c), the at least one thermoplastic polyester being selected from the group consisting of aliphatic polyesters, aliphatic-aromatic polyesters and mixtures thereof.

[0020] The present invention has several benefits:

[0021] - the thermoplastic polymer blends according to the invention have better mechanical properties than known blends based on thermoplastic native starch and a polyester selected from the group of aliphatic polyesters and aliphatic-aromatic polyesters;

[0022] - the thermoplastic polymer blends according to the invention can be obtained by a cost-effective process, since only small amounts of expensive modified starch are required to improve the mechanical properties of the blend;

[0023] - Thermoplastic polymer blends accordingly allow to increase the throughput in the extrusion process without imparting mechanical properties to the product obtained;

[0024] - The thermoplastic polymer blends of the present invention allow the application of milder conditions in compounding or film production;

[0025] - The presence of a combination of hydrophobically modified TPS and native starch based TPS allows the inclusion of large amounts of polyhydroxyalkanoates, such as biodegradable polyesters based on vegetable oils (PHBH), which would otherwise not be possible due to the incompatibility between hydrophobic polyhydroxyalkanoates and starch.

[0026] Therefore, another aspect of the present invention is a process for preparing a thermoplastic blend according to the present invention, the process comprising the following steps:

[0027] (i) providing at least one component (a) or a combination of hydrophobically modified starch and one or more plasticizers, said combination being converted in step (iv) into a thermoplastic hydrophobically modified starch (a);

[0028] (ii) providing at least one thermoplastic native starch (b) or a combination of a native starch and one or more plasticizers, and converting the combination into the thermoplastic native starch (b) in step (iv);

[0029] (iii) providing at least one polyester (c) and, if desired, one or more additives (d);

[0030] (iv) mixing the components provided in steps (i) to (iii) to obtain a blend.

[0031] The invention also relates to a monolayer or multilayer film comprising at least one layer made from the thermoplastic polymer blend according to the invention. DETAILED DESCRIPTION

[0032] Here and throughout the specification, the terms "thermoplastic polymer blend", "thermoplastic polymer blend containing TPS" and "starch blend" are used synonymously.

[0033] Here and throughout the specification, the terms "thermoplastic starch" and "TPS" refer to the sum of the amounts of starch and plasticizer, excluding the water content present in, for example, native starch. Therefore, the relative amounts of thermoplastic starch (TPS) given herein refer to the relative weight of the sum of the weight of starch and the weight of plasticizer, excluding the water content present in, for example, native starch.

[0034] The term "polyester" also includes polyesteramides, polyetheresters, polyester polyurethanes and polyester carbonates, including aliphatic and semiaromatic polyesteramides, aliphatic and semiaromatic polyetheresters, aliphatic and semiaromatic polyester polyurethanes and aliphatic and semiaromatic aliphatic polyester carbonates.

[0035] In the context of the present invention, the term "thermoplastic" means that the corresponding polymer material becomes flexible or moldable at a certain temperature without destroying the polymer and solidifies below said temperature.

[0036] Here and throughout the specification, the terms "wt. %" and "weight %" are used synonymously.

[0037] Here and throughout the specification, the terms "polylactic acid" and "polylactide" are used synonymously.

[0038] "Molecular weight Mn" or "molar mass Mn" is the number average molecular weight or molar mass. "Molecular weight Mw" or "molar mass Mw" is the mass average molecular weight or molar mass. If not otherwise stated, Mn and Mw are determined by GPC with an RI (refractive index) detector, using a mixture of hexafluoroisopropanol and 0.05% potassium trifluoroacetate as eluent (temperature: 40° C., flow rate: 1 mL / min) and using polymethyl methacrylate of a specified molecular weight as a standard for calibration.

[0039] Here and throughout the specification, if not stated otherwise, the melt volume rate (MVR) refers to the value determined according to EN ISO 1133 (190° C., 5 kg weight).

[0040] Here and throughout the specification, the acid number (AN) is determined according to the following method: 0.9 g to 1.1 g of polymer (recorded with an accuracy of 1 mg) is dissolved in a mixture of 10 mL of toluene and 10 mL of pyridine. A cooler is added and the mixture is heated at 50° C. for about 1 h with stirring. After adding 5 mL of deionized water, the mixture is cooled to room temperature and 50 mL of tetrahydrofuran is added through a cooler. The solution is potentiometrically titrated with a standard solution of potassium hydroxide in ethanol of known concentration. The blind value is determined in the same procedure, but without the polymer.

[0041] Here and throughout the description, if not stated otherwise, any value for the hydroxyl number refers to the value determined in accordance with DIN EN ISO 4629-2.

[0042] Here and throughout the description, the viscosity number (VN) is determined in accordance with DIN 53728-3:1985-1 at 25° C. using a solution of the corresponding polymer in a 50:50 w / w mixture of phenol and 1,2-dichlorobenzene.

[0043] Here and throughout the description, if not stated otherwise, the glass transition temperature (Tg) is determined by dynamic differential calorimetry (DSC) in accordance with DIN EN ISO 11357-1:2017-02.

[0044] Here and throughout the specification, the terms "melting temperature (Tm)" and "melting point" are used synonymously. If not otherwise stated, Tm is determined by dynamic differential calorimetry (DSC) according to DIN EN ISO 11357-3:2018-07.

[0045] The residual moisture content was determined by Karl-Fischer titration method B2 according to EN ISO 15512:2019 at a heating temperature of 130°C using a Mettler-Toledo InMotion KF PRO oven autosampler.

[0046] In the context of the present invention, a substance or a mixture of substances meets the characteristic "biodegradable" when it has a percentage degree of biodegradability of at least 90% according to DIN EN 13432. In general, biodegradability causes the polymer blend to decompose within an appropriate and detectable time interval. Degradation can be carried out by enzymatic, hydrolytic, oxidative and / or by the action of electromagnetic radiation (e.g., UV radiation), and is usually mainly achieved by the action of microorganisms (such as bacteria, yeast, fungi and algae). Biodegradability can be quantitatively determined, for example, by mixing the polymer blend with compost and storing it for a certain time. For example, according to DIN EN 13432, air without CO2 is allowed to flow through mature compost during composting, and the compost is subjected to a defined temperature program. Here, the biodegradability is defined as the percentage degree of biodegradability via the net CO2 release of the sample (after deducting the CO2 release of the compost without the sample) to the maximum CO2 release of the sample (calculated by the carbon content of the sample). Biodegradable polymer blends often show significant degradation phenomena, such as fungal growth and the formation of cracks and holes, after only a few days of composting.Other methods for determining biodegradability are described, for example, in ASTM D 5338 and ASTM D 6400-4.

[0047] Throughout the specification, the terms "single-layer film" and "multi-layer film" are to be understood as a film comprising only a single layer and a film comprising at least two layers, respectively.

[0048] The thermoplastic polymer blend according to the invention comprises as component (a) at least one thermoplastic hydrophobically modified starch and as component (b) at least one thermoplastic native starch.

[0049] Here and throughout the specification, the term "starch" refers to both natural starch and modified starch. The term "hydrophobic TSP" refers to the thermoplastic hydrophobically modified starch of component (a). The term "native TSP" refers to the plasticized natural starch of component (b). The term "native starch" refers to any non-modified starch obtained from starch-producing plants such as tubers, grains or legumes.

[0050] The starch used to produce the native TSP and the starch used to produce the hydrophobically modified starch can be any conventional native starch, including starch from tubers, cereals or legumes, such as pea starch, corn starch (including waxy corn starch), potato starch (including waxy potato starch), amaranth starch, rice starch (including glutinous rice starch), wheat starch (including waxy wheat starch), barley starch (including waxy barley starch), cassava starch (including waxy cassava starch) and sago starch. Starches generally have an amylose content of 20% to 30% by weight, depending on the plant species from which they are obtained. In particular, starches rich in amylopectin (which have a significantly increased amylopectin content) or products containing an increased amylose content also belong to this category. In addition to amylopectin-rich natural starch types and high amylose types obtained by breeding measures, amylopectin-rich starches or high amylose starches obtained by chemical and / or physical fractionation or produced by genetically modified plants can also be used.

[0051] Native starch as well as hydrophobically modified starch can be processed into so-called "thermoplastic starch (TPS)" by treating them with plasticizers by conventional polymer processing techniques such as extrusion, injection molding and compression molding to form native TPS and hydrophobic TPS, respectively.

[0052] The literature describes many low molecular weight and relatively high molecular weight compounds as plasticizers for starch. Suitable examples of plasticizers include, but are not limited to, water and polyols and mixtures thereof. Preferably, the polyols selected from the group consisting of glycerol, sorbitol, sorbitol esters, oligomerized glycerol, pentaerythritol, erythritol, xylitol, mannitol and mixtures thereof are preferred. Particularly preferred are glycerol, sorbitol and oligomerized glycerol (oligoglycerol), erythritol and mixtures thereof.

[0053] Suitable oligoglycerols that can be used as plasticizers are described in WO 2012 / 017095 and WO 2017 / 153431. In particular, in order to very significantly avoid evaporation of monoglycerol during subsequent film extrusion, the monoglycerol content of the oligoglycerol is preferably less than 10% by weight, based on the total weight of the oligoglycerol.

[0054] Particularly preferred is sorbitol as plasticizer both for native starch and for hydrophobically modified starch, and particularly preferred is an aqueous sorbitol solution having a sorbitol content of generally 40 to 80% by weight, in particular 45 to 75% by weight and especially 50 to 70% by weight, based on the total weight of the aqueous sorbitol solution.

[0055] The mixture for producing thermoplastic starch generally comprises 5 to 30% by weight, preferably 10 to 26% by weight and in particular 18 to 26% by weight of plasticizer, based on the total weight of the mixture.

[0056] Preferably, the mixture for producing the thermoplastic starch contains sorbitol or erythritol as plasticizer in an amount of 10 to 15 wt %, based on the total weight of the mixture of plasticizer and starch.

[0057] According to the present invention, component (a) is a thermoplastic hydrophobically modified starch. Modified starch may also be referred to as "functionalized starch" or "derivatized starch". In the context of the present invention, the terms "functionalization", "derivatization" and "modification" of starch are used synonymously.

[0058] Hydrophobically modified starches and hydrophobic TSPs have long been known in the art, for example from G. Tegge, und (Starch and Starch derivatives), 3rd edition. B. Behr's Verlag GmbH & Co. KG, Hamburg, 2004, pp. 189-214 and commercially available, for example, from Roquette, Cargill, Ingredion, Avebe, Archer Daniel Midlands, Emsland Group or Agrana.

[0059] In hydrophobically modified starch, at least some of the hydroxyl groups of the starch are modified by hydrophobic groups, i.e. the hydroxyl groups are converted into aprotic groups such as ester or ether groups or carbamate groups. Therefore, hydrophobically modified starch derivatives are divided into starch esters and starch ethers.

[0060] In hydrophobically modified starch, generally on average at least 0.0025 mol, in particular at least 0.01 mol, for example 0.0025 mol to 0.25 mol, in particular 0.01 mol to 0.1 mol of the hydroxyl groups of the anhydroglucose units of the starch are modified. This corresponds to a degree of substitution DS of at least 0.01, in particular at least 0.04, for example 0.01 to 1, in particular 0.04 to 0.4. DS means the average amount of the modified anhydroglucose units of the starch. The term "modification" means that the hydrogen atoms of the hydroxyl groups are replaced by groups that impart hydrophobicity to the starch. The groups that impart hydrophobicity to the starch (hereinafter referred to as hydrophobic groups) are generally saturated hydrocarbon groups, such as alkyl, alkenyl or cycloalkyl groups having 1 to 40 carbon atoms, in particular 2 to 30 carbon atoms, in particular 5 to 30 carbon atoms; aromatic hydrocarbon groups having 1 to 40 carbon atoms, in particular 2 to 30 carbon atoms, in particular 5 to 30 carbon atoms; or trialkylsilane groups. The hydrophobic group may be attached to the oxygen atom of the modified hydroxyl group directly or via a linker such as a carbonyl group, a urea group, a hydroxyalkyl group or a carboxyalkyl group. The hydrocarbyl group may carry 1 or 2 hydroxyl groups or 1 or 6 ether groups or 1, 2 or 3 carboxyl groups, provided that the total number of carbon atoms exceeds the total number of hydroxyl groups, carboxyl groups and ether groups.

[0061] The total amount of hydrophobic groups in the starch is generally in the range from 0.1% to 20% by weight, in particular in the range from 0.5% to 10% by weight, based on the total weight of the hydrophobically modified starch.

[0062] Preferably, the modified OH group is present in the form of an ester or ether group or a carbamate group, wherein the hydrogen atom of the OH group is replaced by a hydrophobic group as defined above. Typically, the hydrophobically modified starch is non-ionic, i.e. the group replacing the hydrogen atom of the OH group of the starch does not carry any ionic group or a group capable of forming an ionic group, such as an acidic group or a basic group. In other words, the hydrogen atom of the modified OH group of the starch is replaced by a non-ionic group. In some cases, the group may carry a carboxyl group, provided that the total number of carbon atoms of the group is at least 5, for example 5 to 40.

[0063] The modification of the hydroxyl groups in the unmodified starch is achieved by reacting the unmodified starch with an agent capable of forming bonds with the oxygen atoms of the hydroxyl groups of the starch and carrying a hydrophobic group as described above. Such agents are also referred to as "hydrophobizing agents". Methods for hydrophobic modification are known to the skilled person and can be carried out in slurries, pastes, (semi-)dry processes by reactive extrusion and in organic solvents.

[0064] The non-modified starch used to prepare the hydrophobically modified starch can be any natural starch as described above. However, the non-modified starch used to prepare the hydrophobically modified starch can also be a degraded natural starch. The degradation process can be hydrolytic (acid catalyzed), oxidative, mechanical, thermal, thermochemical or enzymatic. In this way, the starch can not only be structurally changed, but also the starch product can be made soluble or swellable in cold water.

[0065] Hydrophobically modified starches are usually prepared by esterification or etherification of non-modified starches.

[0066] For the esterification, the unmodified starch is reacted with carboxylic acids or their ester-forming derivatives (such as anhydrides and acid chlorides) or carboxylic acid esters (such as methyl or ethyl esters), or diketene. Mixed esters or anhydrides can also be used. Suitable esterifying agents are in particular monocarboxylic acids of the formula RCOOH, their ester-forming derivatives and cyclic anhydride dicarboxylic acids carrying a radical R, where R can be an alkyl, aryl, alkenyl, alkaryl or aralkyl radical having 1 to 30 carbon atoms, in particular 1 to 20 carbon atoms, especially 1 to 12 carbon atoms.

[0067] Etherification is usually carried out by reacting the unmodified starch with a suitable alkylating agent, including

[0068] - alkylene oxides, in particular alkylene oxides containing 2 to 20 carbon atoms, preferably 2 to 6 carbon atoms, in particular 2 to 4 carbon atoms, such as ethylene oxide, propylene oxide, butylene oxide or styrene oxide;

[0069] - glycidyl ethers, such as alkyl glycidyl ethers, cycloalkyl glycidyl ethers, aryl glycidyl ethers and alkyl-substituted aryl glycidyl ethers, for example o-cresyl glycidyl ether, poly(propylene glycol) diglycidyl ether, tert-butylphenyl glycidyl ether, ethylhexyl glycidyl ether and hexanediol mono- and diglycidyl ethers;

[0070] - glycidyl esters, such as alkyl glycidyl esters, aryl glycidyl esters and alkyl-substituted aryl glycidyl esters, for example C2-C 20 C2-C 20 Alkanoic acid or C5-C 20 Glycidyl esters of cycloalkanoic acids, such as glycidyl ester of neodecanoic acid or glycidyl ester of cyclohexanoic acid and glycidyl ester of benzoic acid;

[0071] - alkyl halides, such as methyl chloride and ethyl chloride;

[0072] - dialkyl carbonates, such as dimethyl carbonate and diethyl carbonate;

[0073] - dialkyl sulfates, such as dimethyl sulfate and diethyl sulfate;

[0074] - epoxidized vegetable oils, such as epoxidized soybean oil, epoxidized sunflower oil, epoxidized rapeseed oil, epoxidized linseed oil and mixtures thereof; and

[0075] - trialkylsilanes, such as trimethylsilane.

[0076] In one preferred set of embodiments (1), the hydrophobic TSP of component (a) is based on a hydrophobically modified starch which has been reacted with an epoxide, the epoxide being in particular selected from the group consisting of alkyl glycidyl ethers, aryl glycidyl ethers, alkyl-substituted aryl glycidyl ethers, aryl glycidyl esters, alkyl-substituted aryl glycidyl esters, alkyl glycidyl ethers, alkyl glycidyl esters, cycloalkyl glycidyl esters as defined above and epoxidized vegetable oils and combinations thereof.

[0077] In a very preferred subgroup (1a) of group (1) of the embodiment, the hydrophobic TSP of component (a) is based on starch that has been hydrophobically modified with one or more epoxidized vegetable oils. Suitable examples of epoxidized vegetable oils of group (1a) include, but are not limited to, epoxidized soybean oil, epoxidized sunflower oil, epoxidized rapeseed oil, epoxidized linseed oil, and mixtures thereof.

[0078] Suitable examples of epoxidized vegetable oils of group (1) include in particular epoxidized soybean oil (ESBO) and epoxidized linseed oil (ELO). Epoxidized linseed oil generally has a viscosity of about 900 mPas at 25° C. and an epoxide oxygen content of at least 8.5% by weight, based on the total weight of the oil. Epoxidized soybean oil generally has a viscosity of about 300 mPas to 450 mPas (also at 25° C.) and an epoxide oxygen content of 6.5% to 7.5% by weight, based on the total weight of the oil. The viscosity measurements carried out for the purposes of the present invention are each carried out in a viscometer in accordance with EN ISO 3219.

[0079] The amount of epoxidized vegetable oil is in particular in the range from 0.1% to 6% by weight, preferably in the range from 1% to 4.5% by weight, particularly preferably in the range from 2.5% to 3.5% by weight, based on the total weight of non-modified starch and epoxidized vegetable oil.

[0080] The hydrophobically modified starches and hydrophobic TSPs of group (1a) of the embodiment are known from WO 2019 / 138022 and WO 2020136231 and can be obtained, for example, from Agrana It is commercially available from ELECTRONICS GmbH, Austria.

[0081] In another preferred group of embodiments (2), the hydrophobic TSP of component (a) is based on starch which has been hydrophobically modified with ethers. In the context of the present invention, the ethers of this group (2) are in particular different from the ethers containing epoxy groups mentioned above in group (1).

[0082] Suitable examples of ethers include, but are not limited to, alkyl ethers such as methyl ether, ethyl ether; hydroxyalkyl ethers such as hydroxyethyl ether, hydroxypropyl ether, hydroxybutyl ether; cyanoalkyl ethers such as cyanoethyl ether; carbamoyl alkyl ethers such as carbamoyl ethyl ether; and alkylene oxides (C1-C12) containing 1 to 20 carbon atoms. 20 -alkylene oxides), preferably alkylene oxides having 2 to 6 carbon atoms (C2-C6-alkylene oxides), in particular alkylene oxides having 2 to 4 carbon atoms (C2-C4-alkylene oxides), in particular ethylene oxide and propylene oxide. The alkyl chain length of the alkyl ethers of group (2) is generally in the range from 1 to 20 carbon atoms, in particular in the range from 1 to 10 carbon atoms, and in particular in the range from 1 to 5 carbon atoms.

[0083] In another preferred embodiment (3), the hydrophobic TSP of component (a) is based on starch which has been hydrophobically modified with ester groups. The ester groups are generally derived from monocarboxylic acids of the formula RCOOH, wherein R can be an alkyl, aryl, alkenyl, alkaryl or aralkyl group having 1 to 30 carbon atoms, in particular 1 to 20 carbon atoms, especially 1 to 12 carbon atoms, or from cyclic anhydrides of dicarboxylic acids, such as succinic anhydride or glutaric anhydride, wherein the cyclic anhydride carries a group R as defined herein. Examples of esters of group (3) include, but are not limited to:

[0084] - starch and a monocarboxylic acid (C1-C 20 -carboxylic acids), especially monocarboxylic acids with 1 to 18 carbon atoms (C1-C 18 -carboxylic acids), in particular esters with alkyl, aryl, alkenyl, alkaryl or aralkylcarboxylic acids, wherein the alkyl, aryl, alkenyl, alkaryl or aralkyl radical thereof has 1 to 19 carbon atoms, in particular 1 to 17 carbon atoms, exemplified by acetic acid, propionic acid, butyric acid, oleic acid, stearic acid and benzoic acid

[0085] - Esters of starch with at least one anhydride of an alkyl or alkenyl substituted dicarboxylic acid, in particular an alkyl or alkenyl substituted C4-C8 dicarboxylic anhydride, such as alkyl substituted succinic anhydride and alkenyl substituted succinic anhydride. In the alkyl or alkenyl substituted dicarboxylic anhydride, the alkyl and alkenyl groups generally have 1 to 19 or 2 to 19 carbon atoms, in particular 2 to 17 carbon atoms. An example is octenyl succinic anhydride.

[0086] In a very preferred subgroup (3a) of group (3) of embodiments, the hydrophobic TSP of component (a) is based on starch which has been hydrophobically modified with one or more fatty acids or ester-forming derivatives thereof, such as acid chlorides. Suitable fatty acids may be of vegetable or animal origin and include in particular C 12 -C 20 Fatty acids, which may be saturated or unsaturated.

[0087] In another very preferred subgroup (3a) of group (3) of the embodiment, the hydrophobic TSP of component (a) is based on starch which has been hydrophobically modified with one or more alkenyl-substituted dicarboxylic anhydrides, in particular with alkyl- or alkenyl-substituted C4-C8 dicarboxylic anhydrides, such as the alkyl-substituted succinic anhydrides and alkenyl-substituted succinic anhydrides described above.

[0088] In another preferred embodiment (4), the hydrophobic TSP of component (a) is based on starch which has been hydrophobically modified with isocyanate. The starch thus modified will carry carbamate groups in which the nitrogen atoms are substituted by hydrocarbon groups having 1 to 40 carbon atoms, in particular 2 to 20 carbon atoms. Typically, the isocyanate has the formula R-NCO, in which R can be an alkyl, aryl, alkenyl, alkaryl or aralkyl group having 1 to 30 carbon atoms, in particular 1 to 20 carbon atoms, especially 1 to 12 carbon atoms.

[0089] In another preferred embodiment (5), the hydrophobic TSP of component (a) is based on starch that has been hydrophobically modified with C2-C4-alkylene oxides. In the context of the present invention, the C1-C4-alkylene oxides of group (5) are different from those of group (1). Suitable examples of C2-C4-alkylene oxides of group (5) include, but are not limited to, alkylene oxides having 2 to 4 carbon atoms. Preferred are ethylene oxide, propylene oxide and butylene oxide, particularly preferred are ethylene oxide and propylene oxide, and especially preferred is propylene oxide. Different amounts of C1-C4-alkylene oxides of group (5) can be used, depending on the desired properties and economics. Generally speaking, based on the weight of the starch, 15% by weight or less, preferably 1% to 15% by weight, more preferably 10% by weight or less, particularly preferably 1% to 10% by weight of C1-C4-alkylene oxides of group (5) are used.

[0090] Hydrophobically modified starch is prepared by reacting a hydrophobizing agent selected from groups (1) to (5), preferably selected from groups (1) to (3), (3a), (3b) and (1a), more preferably selected from groups (1a), (3a) and (3b). The reaction is usually carried out at an elevated temperature, for example in the range of 50°C to 200°C, particularly in the range of 80°C to 180°C. The reaction of non-modified starch with the hydrophobizing agent can be promoted by using an acidic catalyst, particularly if the hydrophobizing agent is an epoxide. In this case, the pH of the reaction mixture containing starch, hydrophobizing agent and optional diluent (such as plasticizer) is preferably adjusted to a pH less than about 7 by adding an organic or inorganic acid (such as hydrochloric acid, citric acid or sulfuric acid). The reaction can be carried out in an inert diluent or in a substance. Modification can be carried out with thermoplastic starch, i.e. plasticized starch, or with non-plasticized starch. In particular, it may be beneficial to carry out modification and plasticization of non-modified starch in a single step to produce a hydrophobic TSP, as described, for example, in WO 2019 / 138022.

[0091] In particular, component (a) comprises one or more plasticizers selected from the group consisting of glycerol, sorbitol, sorbitol esters, oligomerized glycerol, pentaerythritol, erythritol, xylitol, mannitol and mixtures thereof, in particular selected from the group consisting of glycerol, sorbitol, oligomerized glycerol (oligoglycerol), erythritol and mixtures thereof.

[0092] Component (a) is preferably prepared by a process in which a mixture of non-modified starch, in particular native starch, polyols, preferably selected from the group consisting of polyethylene glycols, monosaccharides and disaccharides, sugar alcohols, such as glycerol, sorbitol, erythritol, xylitol or mannitol and mixtures thereof, in an amount of 10 to 25% by weight, preferably 10 to 15% by weight and in particular 13 to 15% by weight, based on the total weight of the mixture, and 0.1 to 6% by weight, preferably 1 to 4.5% by weight and particularly preferably 2.5 to 3.5% by weight, based on the total weight of the mixture, of an epoxide from group (1a), in particular at a temperature of at least 50° C., in particular at least 80° C., for example in the range of 50 to 200° C., in particular in the range of 80 to 180° C., are reacted.

[0093] The amount of component (a) in the blend is generally in the range of 0.1 wt % to 35 wt %, for example in the range of 1 wt % to 35 wt %, preferably in the range of 2 wt % to 30 wt %, especially in the range of 5 wt % to 25 wt %, based on the total weight of the mixture in anhydrous form (calculated as component (a) in anhydrous form).

[0094] Here and hereinafter, the term "anhydrous form" in the context of the weight of components (a) and (b) and the weight of the blend is to be understood as meaning that the amounts given for components (a) and (b) are calculated in the absence of any plasticizers (water and organic plasticizer), and therefore refer to the amount of starch or hydrophobically modified starch free of water and organic plasticizer, and that the weight of the blend is the weight of the ingredients excluding water and organic plasticizer.

[0095] Component (a) generally has a number average molecular weight (Mn) in the range of 5000 g / mol to 500000 g / mol, in particular in the range of 10000 g / mol to 300000 g / mol. The weight average molecular weight (Mw) of component (a) is generally in the range of 50000 g / mol to 2000000 g / mol, preferably in the range of 100000 g / mol to 1000000 g / mol.

[0096] The blend of the invention also contains thermoplastic natural starch as component (b).

[0097] In principle, any of the above-mentioned native starches can be used to produce thermoplastic native starches. Preferably, the native TSP of component (b) is a plasticizing starch selected from corn starch, potato starch, wheat starch, pea starch or rice starch or a mixture thereof. In particular, the native TSP of component (b) is a plasticizing starch selected from wheat starch, corn starch and potato starch and a mixture thereof, and is particularly preferably selected from corn starch or potato starch and a mixture thereof.

[0098] Similar to component (a), component (b) can be produced by processing native starch into thermoplastic native starch together with plasticizer using conventional polymer processing technology as mentioned above. Suitable examples of plasticizer include but are not limited to water and polyols and their mixtures. Especially, polyols are used as the plasticizer of native starch. Suitable polyols for preparing component (b) include but are not limited to glycerine, sorbitol, sorbitol ester, oligomerization glycerine, pentaerythritol, erythritol, xylitol, mannitol and their mixtures, and particularly preferably glycerine, sorbitol, oligomerization glycerine (oligoglycerine), erythritol and their mixtures.

[0099] Sorbitol is also particularly preferred as a plasticizer for native starch, and particularly preferred here is an aqueous sorbitol solution whose sorbitol content is generally 40% to 80% by weight, particularly 45% to 75% by weight and especially 50% to 70% by weight, based on the total weight of the aqueous sorbitol solution. The aqueous sorbitol solution particularly preferred as a plasticizer for native starch is also as described above.

[0100] The mixture for producing the thermoplastic native starch generally comprises 10% to 30% by weight, preferably 15% to 26% by weight and in particular 18% to 26% by weight of plasticizer, based on the total weight of the mixture.

[0101] The amount of component (b) in the blend is generally in the range of 3 wt % to 69.9 wt %, preferably in the range of 5 wt % to 63 wt %, especially in the range of 10 wt % to 55 wt %, based on the total weight of the mixture in anhydrous form (calculated as component (b) in anhydrous form).

[0102] The total amount of components (a) and (b), calculated in their anhydrous form, based on the total weight of the blend in anhydrous form, is generally in the range from 5% to 70% by weight, in particular in the range from 7% to 65% by weight and in particular in the range from 15% to 60% by weight.

[0103] In particular, the polymer blend comprises the following relative amounts of components (a) and (b):

[0104] (a) 1 to 70% by weight, preferably 5 to 60% by weight, in particular 6 to 58% by weight, of component (a), based on the total weight of components (a) and (b), and

[0105] (b) 30% to 99% by weight, preferably 40% to 95% by weight, in particular 42% to 94% by weight, of component (b), based on the total weight of components (a) and (b),

[0106] Components (a) and (b) are calculated in their anhydrous form.

[0107] In particular, the weight ratio of components (a):(b) is in the range of 1:99 to 3:7, more particularly in the range of 1:19 to 3:2, especially in the range of 1:1.35 to 13:1.

[0108] The thermoplastic polymer blend according to the present invention further comprises as component (c) at least one thermoplastic polyester selected from the group consisting of aliphatic polyesters, aliphatic-aromatic polyesters and mixtures thereof.

[0109] The amount of component (c) in the blend is generally in the range of 30 to 95 wt %, preferably in the range of 35 to 93 wt %, especially in the range of 40 to 85 wt %, based on the total weight of the blend in anhydrous form.

[0110] In particular, the weight ratio of components (a):(c) is in the range of 1:100 to 1:1, in particular in the range of 1:40 to 1:1.5, and especially in the range of 1:20 to 1:2.

[0111] In particular, the weight ratio of components (b):(c) is in the range of 1:30 to 2:1, in particular in the range of 1:20 to 1.2:1, and especially in the range of 1:15 to 1:1.

[0112] Preferably, the polyester of component (c) has a relative humidity of 0.5 cm according to EN ISO 1133 (190° C., 2.16 kg weight). 3 / 10min to 70cm 3 / 10min, preferably within 0.5cm 3 / 10min to 30cm 3 The melt volume rate (MVR) is in the range of 10 min / 10 min.

[0113] Preferably, the polymer blend according to the invention comprises at least one polyester (c) having a melting temperature Tm in the range of 45° C. to 160° C., in particular in the range of 50° C. to 150° C., especially in the range of 60° C. to 140° C. If the polymer has a melting point, it is semicrystalline or crystalline. If the polymer is amorphous, it preferably has a softening temperature in the range of 45° C. to 160° C., in particular in the range of 50° C. to 150° C., especially in the range of 60° C. to 140° C. The softening temperature is understood to be the Vicat softening temperature (VST), which is determined according to DIN EN ISO 306:2014-03 at a heating rate of 50° C. / h by applying a point load of 10 N to the test specimen, and, if not otherwise stated, is referred to as the VST / A50 temperature.

[0114] Polyester (c) generally has a number average molecular weight (Mn) in the range of 2000 g / mol to 100000 g / mol, in particular in the range of 5000 g / mol to 80000 g / mol, preferably in the range of 7000 g / mol to 70000 g / mol, a weight average molecular weight (Mw) in the range of 3000 g / mol to 300000 g / mol, preferably 3000 g / mol to 200000 g / mol, in particular in the range of 15000 g / mol to 200000 g / mol. The Mw / Mn ratio is generally in the range of 1 to 6, in particular in the range of 2 to 5.

[0115] The viscosity number (VN) of the polyester (c) is usually in the range of 50 g / ml to 450 g / ml, preferably in the range of 80 g / ml to 250 g / ml. The melting point measured by DSC is usually in the range of 85°C to 150°C, preferably in the range of 95°C to 140°C.

[0116] The polyester (c) may have any ratio of hydroxyl and / or carboxyl end groups. In particular, the polyester (c) has an acid value of less than 1.5 mg KOH / g, as determined by the above procedure.

[0117] In particular, component (c) is biodegradable, in particular biodegradable according to DIN EN 13432.

[0118] A distinction is made between aliphatic-aromatic polyesters composed of aliphatic diols and aliphatic and aromatic diacids (hereinafter referred to as component (c1)) and aliphatic polyesters composed of aliphatic diols and aliphatic diacids or of hydroxyalkanoic acids or cycloaliphatic lactones (hereinafter referred to as component (c2)).

[0119] Aliphatic-aromatic polyesters (c1) are also called semiaromatic polyesters, i.e. polyesters based on aromatic dicarboxylic acids and aliphatic dihydroxy compounds, and polyesters based on mixtures of aromatic dicarboxylic acids with aliphatic dicarboxylic acids and aliphatic dihydroxy compounds. Aliphatic-aromatic polyesters are preferably polyesters based on mixtures of aliphatic dicarboxylic acids with aromatic dicarboxylic acids and aliphatic dihydroxy compounds. These polymers may be present alone or in the form of a mixture thereof.

[0120] Preferably, "aliphatic-aromatic polyesters" are also understood to mean polyester derivatives, such as polyetheresters, polyesteramides or polyetheresteramides and polyester polyurethanes, as described, for example, in WO 2012 / 2013506. Suitable aliphatic-aromatic polyesters include linear, non-extended polyesters, as described, for example, in WO 92 / 09654. Preference is given to chain-extended and / or branched aliphatic-aromatic polyesters. The latter are known from WO 96 / 15173, WO 96 / 15174, WO 96 / 15175, WO 96 / 15176, WO 96 / 21689, WO 96 / 21690, WO 96 / 21691, WO 96 / 21692, WO 96 / 25446, WO 96 / 25448 and WO 98 / 12242, to which reference is expressly made. Mixtures of different aliphatic-aromatic polyesters are likewise conceivable. Interesting recent developments are based on renewable raw materials and are described, inter alia, in WO 2006 / 097353, WO 2006 / 097354 and WO 2010 / 034710.

[0121] As described herein, preferred aliphatic-aromatic polyesters (c1) are characterized by a number average molecular weight Mn determined by GPC in the range of 5000 g / mol to 100000 g / mol, in particular in the range of 10000 g / mol to 75000 g / mol, preferably in the range of 15000 g / mol to 50000 g / mol. As described herein, preferred aliphatic-aromatic polyesters (c1) are characterized by a weight average molecular weight determined by GPC in the range of 50000 g / mol to 250000 g / mol, in particular in the range of 70000 g / mol to 200000 g / mol, preferably in the range of 90000 g / mol to 150000 g / mol. They generally have a melting point in the range from 60° C. to 170° C., preferably in the range from 80° C. to 150° C., in particular in the range from 100° C. to 140° C., determined by DSC starting from a melt at 200° C., holding for 5 min and subsequently cooling the melt at a cooling rate of 20 K / min.

[0122] Preferred aliphatic-aromatic polyesters contain as essential components:

[0123] - an acid component, the acid component comprising

[0124] c1-i. 20 mol % to 95 mol %, in particular 20 mol % to 90 mol %, and especially 20 mol % to 85 mol % of at least one aliphatic dicarboxylic acid or its ester-forming derivative or a mixture thereof as component i, based on the total molar percentage of components i and ii;

[0125] c1-ii. Based on the total molar percentage of components i and ii, 5 mol% to 80 mol%, in particular 10 mol% to 80 mol%, especially 15 mol% to 80 mol% of at least one aromatic dicarboxylic acid or its ester-forming derivative or a mixture thereof as component ii;

[0126] -c1-iii. At least one of component iii is selected from C2-C 12 - alkanediol diols;

[0127] -Optionally selected from the following components:

[0128] c1-iv. as component c1-iv.a one or more chain extenders and / or as component c1-iv.b one or more branching agents.

[0129] The aliphatic dicarboxylic acids and their ester-forming derivatives (component c1-i) which generally come into consideration are those having 2 to 18 carbon atoms (C2-C 18 -dicarboxylic acids), preferably those having 4 to 18 carbon atoms (C4-C 18-dicarboxylic acids). They may be straight-chain or branched. However, in principle, dicarboxylic acids with a greater number of carbon atoms, for example with up to 30 carbon atoms, may also be used.

[0130] Examples of aliphatic dicarboxylic acids and ester-forming derivatives include, but are not limited to, oxalic acid, malonic acid, succinic acid, 2-methylsuccinic acid, glutaric acid, 2-methylglutaric acid, 3-methylglutaric acid, α-ketoglutaric acid, adipic acid, pimelic acid, azelaic acid, sebacic acid, tridecanedioic acid, fumaric acid, 2,2-dimethylglutaric acid, suberic acid, diglycolic acid, oxaloacetic acid, glutamic acid, aspartic acid, itaconic acid and maleic acid, their anhydrides and their C1-C4-alkyl esters. These dicarboxylic acids or their ester-forming derivatives may be used alone or in the form of a mixture of two or more thereof.

[0131] Preference is given to using succinic acid, adipic acid, azelaic acid, sebacic acid, tridecanedioic acid or their corresponding ester-forming derivatives or mixtures thereof. Particular preference is given to using adipic acid, azelaic acid or sebacic acid or their corresponding ester-forming derivatives or mixtures thereof. As mentioned above, succinic acid, sebacic acid, azelaic acid and tridecanedioic acid also have the advantage of being obtainable from renewable raw materials.

[0132] The aliphatic dicarboxylic acid (component c1-i) is used in an amount of 20 to 90 mol %, in particular 25 to 85 mol % or 30 to 85 mol %, based on the total molar percentage of the acid components c1-i and c1-ii. Sebacic acid, azelaic acid and tridecanedioic acid can be obtained from renewable raw materials, in particular from castor oil.

[0133] Aromatic dicarboxylic acids and their ester derivatives (component c1-ii) can be used alone or in the form of a mixture of two or more thereof. It is particularly preferred to use terephthalic acid or furan-2,5-dicarboxylic acid and their ester derivatives. Di-C1-C6-alkyl esters, such as dimethyl ester, diethyl ester, di-n-propyl ester, diisopropyl ester, di-n-butyl ester, diisobutyl ester, di-tert-butyl ester, di-n-pentyl-ester, diisopentyl ester or di-n-hexyl ester can be mentioned as ester derivatives in particular. The anhydrides of dicarboxylic acids can also be used. A particularly suitable ester derivative of terephthalic acid is dimethyl terephthalate, and a particularly suitable ester derivative of furan-2,5-dicarboxylic acid is furan-2,5-dimethyl dicarboxylate.

[0134] In one set of embodiments, the aromatic dicarboxylic acid is terephthalic acid or its ester-forming derivative. Preferably, based on the total molar percentage of acid components c1-i and c1-ii, terephthalic acid (component c1-ii) or its ester-forming derivative is present in an amount of 30 mol% to 75 mol%, more preferably 35 mol% to 65 mol% and especially 40 mol% to 60 mol%. In this case, based on the total molar percentage of acid components c1-i and c1-ii, the total amount of aliphatic dicarboxylic acids or their ester-forming derivatives is preferably in the range of 25 mol% to 70 mol%, more preferably in the range of 35 mol% to 65 mol% and especially in the range of 40 mol% to 60 mol%.

[0135] In another embodiment, the aromatic dicarboxylic acid is furan-2,5-dicarboxylic acid or its ester-forming derivative. Preferably, based on the total molar percentage of acid components c1-i and c1-ii, furan-2,5-dicarboxylic acid (component c1-ii) or its ester-forming derivative is present in an amount of 40 mol% to 80 mol%, more preferably 50 mol% to 80 mol% and especially 60 mol% to 80 mol%. In this case, based on the total molar percentage of acid components c1-i and c1-ii, the total amount of aliphatic dicarboxylic acids or their ester-forming derivatives is preferably in the range of 20 mol% to 60 mol%, more preferably in the range of 20 mol% to 50 mol% and especially in the range of 20 mol% to 40 mol%.

[0136] Generally, the diol (component c1-iii) is selected from branched or straight chain alkane diols (C2-C 12 -alkanediol), preferably a branched or straight-chain alkanediol having 2 to 6 carbon atoms (C2-C6-alkanediol), or a cycloalkanediol having 5 to 10 carbon atoms (C5-C6-alkanediol). 10Examples of suitable alkanediols are ethylene glycol, propane-1,2-diol, propane-1,3-diol, butane-1,2-diol, butane-1,4-diol, pentane-1,5-diol, 2,4-dimethyl-2-ethylhexane-1,3-diol, 2,2-dimethylpropane-1,3-diol, 2-ethyl-2-butylpropane-1,3-diol, 2-ethyl-2-isobutylpropane-1,3-diol, 2,2,4-trimethylhexane-1,6-diol, in particular ethylene glycol, propane-1,3-diol, butane-1,4-diol and 2,2-dimethylpropane-1,3-diol (neopentyl glycol). Examples of suitable cycloalkanediols are cyclopentanediol, cyclohexane-1,4-diol, cyclohexane-1,2-dimethanol, cyclohexane-1,3-dimethanol, cyclohexane-1,4-dimethanol and 2,2,4,4-tetramethylcyclobutane-1,3-diol. Aliphatic-aromatic polyesters can also comprise combinations of different alkanediols or cycloalkanediols. Particularly preferred are 1,4-butanediol and 1,3-propanediol, especially 1,4-butanediol. Propane-1,3-diol and butane-1,4-diol have the advantage that they are available as renewable raw materials. PCT / EP2008 / 006714 discloses a biotechnological process for preparing 1,4-butanediol starting from different carbohydrates using microorganisms from the family Pasteurellaceae.

[0137] Typically, at the start of the polymerization, the diol (component c1-iii) is adjusted relative to the acid (components c1-i and c1-ii) in a diol to diacid ratio in the range of 1.0 to 2.5:1, and preferably in the range of 1.3 to 2.2:1. Excess diol is removed during the polymerization, so that an approximately equimolar ratio is established at the end of the polymerization. Approximately equimolar is understood to mean a diol / dicarboxylic acid ratio in particular in the range of 0.98 to 1.02:1.

[0138] Thus, component c1-iii is present in the polyester in an amount of 98 to 102 mol %, preferably 99 to 100 mol % and particularly preferably 100 mol %, based on the sum of the mol % of repeat units c1-i and c1-ii.

[0139] The aliphatic-aromatic polyesters may also be end-capped. Thus, for example, the OH end groups may be acid-modified by reaction with phthalic acid, phthalic anhydride, trimellitic acid, trimellitic anhydride, pyromellitic acid or pyromellitic anhydride. Preference is given to aliphatic-aromatic polyesters having an acid number of less than 1.5 mg KOH / g.

[0140] In a preferred group of embodiments, suitable aliphatic-aromatic polyesters (c1) comprise:

[0141] Cl-i, based on the sum of the molar percentages of repeating units c1-i and c1-ii, comprises 25 to 70 mol %, preferably 35 to 65 mol % and in particular 40 to 60 mol % of at least one aliphatic C4-C 18 - Repeating units c1-i of dicarboxylic acid or its ester-forming derivative;

[0142] c1-ii, based on the sum of the molar percentages of repeating units c1-i and c1-ii, 30 mol% to 75 mol%, preferably 35 mol% to 65 mol% and especially 40 mol% to 60 mol% of repeating units c1-ii selected from the group consisting of terephthalic acid, its ester-forming derivatives and mixtures thereof;

[0143] c1-iii, based on the sum of the molar percentages of repeating units c1-i and c1-ii, 98 to 102 mol %, preferably 99 to 100 mol %, in particular 100 mol % of repeating units c1-iii of at least one C2-C6-alkanediol, in particular 1,3-propylene glycol and / or 1,4-butanediol.

[0144] In particular, suitable aliphatic-aromatic polyesters (c1) comprise:

[0145] c1-i, based on the sum of the molar percentages of repeating units c1-i and c1-ii, 25 mol% to 70 mol%, preferably 35 mol% to 65 mol% and especially 40 mol% to 60 mol% of repeating units c1-i selected from the group consisting of succinic acid, adipic acid, sebacic acid, azelaic acid, tridecanedioic acid, their ester-forming derivatives and mixtures thereof; preferably repeating units c1-i selected from the group consisting of adipic acid, sebacic acid, azelaic acid, their ester-forming derivatives and mixtures thereof;

[0146] 30 mol % to 75 mol %, preferably 35 mol % to 65 mol % and especially 40 mol % to 60 mol % of repeating units c1-ii selected from the group consisting of terephthalic acid, dimethyl terephthalate and mixtures thereof, based on the sum of the molar percentages of repeating units c1-i and c1-ii; and

[0147] c1-iii, based on components i to ii, 98 mol % to 102 mol %, preferably 99 mol % to 100 mol %, in particular 100 mol % of repeating units c1-iii selected from the group consisting of 1,3-propylene glycol, 1,4-butanediol and mixtures thereof; preferably repeating units c1-iii of 1,4-butanediol.

[0148] In another preferred embodiment, suitable aliphatic-aromatic polyesters (c1) comprise:

[0149] Cl-i, based on the sum of the molar percentages of the repeating units c1-i and c1-ii', comprises 20 to 60 mol %, preferably 20 to 50 mol % and in particular 20 to 40 mol % of at least one aliphatic C4-C 18 - Repeating units c1-i of dicarboxylic acid or its ester-forming derivative;

[0150] 40 mol % to 80 mol %, preferably 50 mol % to 80 mol % and especially 60 mol % to 80 mol % of repeating units c1-ii' selected from the group consisting of furandicarboxylic acid, its ester-forming derivatives and mixtures thereof, based on the sum of the molar percentages of repeating units c1-i and c1-ii';

[0151] c1-iii, based on the sum of the molar percentages of repeating units c1-i and c1-ii', 98 to 102 mol %, preferably 99 to 100 mol %, in particular 100 mol % of repeating units c1-iii of at least one C2-C6-alkanediol, in particular 1,3-propylene glycol and / or 1,4-butanediol.

[0152] In particular, suitable aliphatic-aromatic polyesters (c1) comprise:

[0153] c1-i, based on the sum of the molar percentages of repeating units c1-i and c1-ii, 20 mol% to 60 mol%, preferably 20 mol% to 50 mol% and especially 20 mol% to 40 mol% of repeating units c1-i selected from the group consisting of succinic acid, adipic acid, sebacic acid, azelaic acid, tridecanedioic acid, their ester-forming derivatives and mixtures thereof; preferably repeating units c1-i selected from the group consisting of adipic acid, sebacic acid, azelaic acid, their ester-forming derivatives and mixtures thereof;

[0154] 40 mol % to 80 mol %, preferably 50 mol % to 80 mol % and especially 60 mol % to 80 mol % of the repeating units c1-ii' and c1-ii' are selected from the group consisting of furandicarboxylic acid, dimethyl furandicarboxylate and mixtures thereof, based on the sum of the molar percentages of the repeating units c1-i and c1-ii'.

[0155] c1-iii, based on components i to ii', 98 mol % to 102 mol %, preferably 99 mol % to 100 mol %, in particular 100 mol % of repeating units c1-iii selected from the group consisting of 1,3-propylene glycol, 1,4-butanediol and mixtures thereof; preferably repeating units c1-iii of 1,4-butanediol.

[0156] In a particularly preferred embodiment, component (c) comprises an aliphatic-aromatic polyester selected from the group consisting of: an aliphatic-aromatic polyester comprising:

[0157] c1-i) 25 to 70 mol %, preferably 35 to 65 mol % and in particular 40 to 60 mol %, based on the sum of the molar percentages of the repeating units c1-i and c1-ii, of at least one aliphatic C4-C 18 - repeating units c1-i of dicarboxylic acid;

[0158] c1-ii) 30 to 75 mol %, preferably 35 to 65 mol % and in particular 40 to 60 mol % of repeating units c1-ii of terephthalic acid, based on the sum of the molar percentages of repeating units c1-i and c1-ii; and

[0159] c1-iii) 98 to 102 mol %, 98 to 100 mol %, preferably 99 to 100 mol %, and in particular 100 mol %, based on the sum of the molar percentages of the repeating units c1-i and c1-ii, of repeating units c1-iii of at least one C2-C6-alkanediol, in particular 1,3-propanediol and / or 1,4-butanediol;

[0160] and

[0161] Aliphatic-aromatic polyesters comprising:

[0162] c2-i) 20 to 60 mol %, preferably 20 to 50 mol % and in particular 20 to 40 mol %, based on the sum of the molar percentages of the repeating units c1-i and c1-ii', of at least one aliphatic C4-C 18 - repeating units c1-i of dicarboxylic acid;

[0163] c2-ii) 40 to 80 mol %, preferably 50 to 80 mol % and in particular 60 to 80 mol % of repeating units c1-ii' of furandicarboxylic acid, based on the sum of the molar percentages of repeating units c1-i and c1-ii'; and

[0164] c2-iii) 98 mol % to 100 102 mol %, preferably 99 mol % to 100 mol %, in particular 100 mol %, based on the sum of the molar percentages of the repeating units c1-i and c1-ii', of at least one C2-C6-alkanediol, in particular repeating units c1-iii of 1,3-propanediol and / or 1,4-butanediol.

[0165] In particular, the aliphatic-aromatic polyester (c1) is selected from poly(butylene adipate-co-terephthalate), poly(butylene sebacate-co-terephthalate), poly(butylene azelaate-co-terephthalate), poly(butylene succinate-co-terephthalate), poly(butylene adipate-co-sebacate-co-terephthalate), poly(butylene adipate-co-zelaic acid-co-terephthalate), poly(butylene adipate-co-succinate-co-terephthalate), poly(butylene sebacate-co-zelaic acid-co-terephthalate), poly(butylene sebacate-co-succinate-co-terephthalate), poly(butylene azelaic acid-co-terephthalate). -succinate-co-terephthalate), poly(butylene adipate-co-furanate), poly(butylene sebacate-co-furanate), poly(butylene azelaate-co-furanate), poly(butylene succinate-co-furanate), poly(butylene adipate-co-sebacate-co-furanate), poly(butylene adipate-co-zelaic acid-co-furanate), poly(butylene adipate-co-succinate-co-furanate), poly(butylene sebacate-co-succinate-co-furanate), poly(butylene azelaic acid-co-succinate-co-furanate), and mixtures thereof. The above-mentioned aliphatic-aromatic polyester has a VST / A50 value in the range of 50°C to 160°C, in particular in the range of 55°C to 150°C.

[0166] In a more preferred embodiment group, the aliphatic-aromatic polyester (c1) is selected from poly(butylene adipate-co-terephthalate) (PBAT), poly(butylene sebacate-co-terephthalate) (PBSeT), poly(butylene azelaate-co-terephthalate) (PBAzT), poly(butylene succinate terephthalate) (PBST), poly(butylene adipate-co-sebacate-co-terephthalate) (PBASeT), poly(butylene adipate-co-zelaate-co-terephthalate) (PBAzT), poly(butylene succinate terephthalate) (PBST), poly(butylene adipate-co-terephthalate) (PBASeT), poly(butylene adipate-co-terephthalate) (PBAzT), poly(butylene succinate terephthalate) (PBS ... Poly(butylene adipate-co-furanate) (PBAF), poly(butylene sebacate-co-furanate) (PBSeF), poly(butylene azelaate-co-furanate) (PBAzF), poly(butylene succinate-co-furanate) (PBSF), poly(butylene adipate-co-sebacate-co-furanate) (PBASeF), poly(butylene adipate-co-azelaate-co-furanate) (PBAAzF) and mixtures thereof.

[0167] Preferably, component (c1) is selected from the group consisting of poly(butylene adipate-co-terephthalate) (PBAT), poly(butylene azelaate-co-terephthalate) (PBAzeT), poly(butylene sebacate-co-terephthalate) (PBSeT), poly(butylene sebacate-co-adipate-co-terephthalate) (PBSeAT), poly(butylene sebacate-co-succinate-co-terephthalate) (PBSeST), poly(butylene azelaate-co-adipate-co-terephthalate), poly(butylene azelaate-co-succinate-co-terephthalate) and mixtures thereof.

[0168] Also preferably, the aliphatic-aromatic polyester (c1) is selected from poly(butylene adipate-co-furanate) and poly(butylene sebacate-co-furanate), poly(butylene azelate-co-furanate) and mixtures thereof.

[0169] Suitable aromatic-aliphatic polyesters (c1) are available, for example, as Level, as Novamont's Origo- Level, as Kingfa Level, as from JinHui Level, as from Xinfu grade and is commercially available as TH802 grade from Xinjiang Blue-Ridge Tunhe.

[0170] Polyester (c1) can be prepared by the method described in WO-A 92 / 09654, WO-A 96 / 15173 or preferably by the method described in US2011034662A1 and US2011039999A1, in particular in a multi-stage reaction cascade. First, a dicarboxylic acid or a derivative thereof is reacted with a diol in the presence of an esterification or transesterification catalyst, and then the volatile components are removed to produce a polyester. The polyester generally has a viscosity number (VN) of 50 ml / g to 300 ml / g, preferably 100 ml / g to 250 ml / g. The catalyst used is generally zinc, aluminum, and in particular a titanium catalyst. Compared with the tin, antimony, cobalt and lead catalysts commonly used in the literature (e.g. tin dioctoate), titanium catalysts (such as tetra(isopropyl) orthotitanate, in particular tetrabutyl orthotitanate (TBOT)) have the following advantages: the residual amount of catalyst remaining in the product or the by-product of the catalyst is less toxic. This is particularly true in the case of biodegradable polyesters, since they can enter the environment directly via composting.

[0171] With both methods described above, the desired MVR range can be tailored simply by selecting process parameters such as residence time, reaction temperature and the amount of volatiles removed during the polycondensation reaction.

[0172] The MVR can be adjusted to higher values ​​by adding components c1-iv) within the stated concentration range or, in the case of polymer mixtures, by suitable compatibilizers.

[0173] The polyester can then be reacted with a chain extender c1-iv.a), for example with a diisocyanate or with an epoxide-containing polymethacrylate, in a chain extension reaction to give a polyester having a VN of 80 to 450 ml / g, preferably 120 to 300 ml / g.

[0174] Melt volume rate (MVR) according to EN ISO 1133 (190°C, 2.16 kg weight) at 0.5 cm 3 / 10min to 70cm 3 / 10min, preferably within 0.5cm 3 / 10min to 50cm 3 / 10min range, especially within 0.5cm 3 / 10min to 30cm 3 / 10min range, especially within 0.5cm 3 / 10min to 20cm 3 Polyesters (c1) having a molecular weight of 0.147 W / m2 and a molecular weight of 0.12 W / m2 are particularly suitable as polyesters (c1).

[0175] Optionally, the polyester, in particular polyester (c1), may comprise 0 to 2% by weight, for example 0.1 to 2.0% by weight, in particular 0.2 to 1.5% by weight and especially 0.3 to 1% by weight, based on the total weight of components c1-i) to c1-iii), respectively, of a further component (iv) or (c1-iv), respectively selected from chain extenders (iv.a) or (c1-iv.a), and branching agents (iv.b) or (c1-iv.b).

[0176] The chain extender (iv.a) or (c1-iv.a) is a polyfunctional compound having at least two reactive groups which are capable of reacting with the terminal functional groups of the polyester and thereby increasing its molecular weight, the polyfunctional compound being selected from the group consisting of difunctional or polyfunctional isocyanates (including diisocyanates and polyfunctional isocyanurates), difunctional or polyfunctional oxazolines, difunctional or polyfunctional carboxylic acid anhydrides (such as maleic anhydride), difunctional or polyfunctional epoxides (especially epoxide-containing poly(meth)acrylates).

[0177] Preferred chain extenders are aliphatic and aromatic diisocyanates and their isocyanurates.

[0178] Examples of aromatic diisocyanates are specifically toluene 2,4-diisocyanate, toluene 2,6-diisocyanate, 2,2'-diphenylmethane diisocyanate, 2,4'-diphenylmethane diisocyanate, 4,4'-diphenylmethane diisocyanate, naphthylene 1,5-diisocyanate or xylylene diisocyanate. Among them, 2,2'-diphenylmethane diisocyanate, 2,4'-diphenylmethane diisocyanate and 4,4'-diphenylmethane diisocyanate are particularly preferred. Generally speaking, the latter diisocyanate is used in the form of a mixture. Based on the total weight of the diisocyanate, the diisocyanate can also contain a small amount, for example, up to 5% by weight of ureathione groups, for example, for blocking isocyanate groups.

[0179] Aliphatic diisocyanates are in particular linear or branched alkylene diisocyanates and cycloalkylene diisocyanates having 2 to 20 carbon atoms, preferably 3 to 12 carbon atoms, for example hexamethylene 1,6-diisocyanate, isophorone diisocyanate or methylenebis(4-isocyanatocyclohexane). Particularly preferred aliphatic diisocyanates are isophorone diisocyanate and in particular hexamethylene 1,6-diisocyanate.

[0180] Preferred isocyanurates include aliphatic isocyanurates derived from alkylene diisocyanates or cycloalkylene diisocyanates having 2 to 20 carbon atoms, preferably 3 to 12 carbon atoms, such as isophorone diisocyanate or methylenebis(4-isocyanatocyclohexane). The alkylene diisocyanates may be linear or branched. Particularly preferred are isocyanurates based on n-hexamethylene diisocyanate, such as cyclic trimers, pentamers or higher oligomers of hexamethylene 1,6-diisocyanate.

[0181] Suitable chain extenders are also polyepoxides. Polyepoxides are particularly selected from homopolymers and copolymers with epoxy groups. The units with epoxy groups are preferably formed by glycidyl esters or glycidyl ethers with ethylenically unsaturated double bonds, in particular by (meth) acrylates. Suitable comonomers are styrene, acrylates and / or methacrylates. Based on the total amount of monomers forming epoxide polymers, copolymers with a certain proportion of (meth) glycidyl acrylate greater than 20% by weight, particularly preferably greater than 30% by weight, and particularly preferably greater than 50% by weight have proven to be advantageous. The epoxide equivalent (EEW) in these polymers is preferably 150 g / equivalent to 3000 g / equivalent, particularly preferably 200 g / equivalent to 500 g / equivalent. The average molecular weight (weight average molecular weight) Mw of the polymer is preferably 2000 g / mol to 25000 g / mol, in particular 3000 g / mol to 8000 g / mol. The average molecular weight (number average molecular weight) Mn of the polymer is preferably 400 g / mol to 6000 g / mol, in particular 1000 g / mol to 4000 g / mol. The polydispersity (Mw / Mn) is generally 1.5 to 5. Copolymers of the above type containing epoxy groups are available, for example, from BASF under the trademark ADR is sold. Particularly suitable chain extenders are ADR 4468 or ADR 4400.

[0182] Branching agents are specifically polyfunctional alcohols, polyfunctional carboxylic acids and polyfunctional carboxylic acid derivatives. Polyfunctional means that the compound has at least three functional groups that can form bonds with the components. Particularly preferred compounds have three to six functional groups. For example, the following substances can be mentioned: tartaric acid, citric acid, malic acid; trimethylolpropane, trimethylolethane, pentaerythritol; polyether triols and glycerol, trimesic acid, trimellitic acid, trimellitic anhydride, pyromellitic acid and pyromellitic anhydride. Preferred are polyols, such as trimethylolpropane, pentaerythritol and in particular glycerol. Generally, it is advantageous to add the branching agent to the polycondensation reaction of the monomers forming the polyester (c) or (c1) at a relatively early time.

[0183] Here and throughout the description, aliphatic polyesters (component c2) are understood to mean polyesters based on one or more aliphatic dicarboxylic acids and one or more aliphatic dihydroxy compounds, polyesters based on aliphatic hydroxycarboxylic acids (optionally in combination with aliphatic dicarboxylic acids and aliphatic diols), and polyesters based on alicyclic lactones (optionally in combination with aliphatic dicarboxylic acids and aliphatic diols). For the preparation of aliphatic-aliphatic polyesters, instead of dicarboxylic acids, it is also possible to use their respective ester-forming derivatives or mixtures thereof with dicarboxylic acids.

[0184] Aliphatic dicarboxylic acids and their ester-forming derivatives which are generally considered are those having 2 to 18 carbon atoms, preferably 4 to 10 carbon atoms. They may be straight-chain or branched. However, in principle, dicarboxylic acids having a greater number of carbon atoms, for example having up to 30 carbon atoms, may also be used.

[0185] Particularly preferred is a melt volume rate (MVR) of 1 cm 3 / 10min to 50cm 3 / 10min, preferably within 1.5cm 3 / 10min to 15cm 3 / 10min range, especially within 1.5cm 3 / 10min to 10cm 3 Aliphatic polyester (c2) in the range of 100 ℃ / 10 min.

[0186] Suitable examples of aliphatic polyesters (c2) include, but are not limited to, polyhydroxyalkanoates (referred to as (c2-a)), polylactic acid (referred to as (c2-b)), aliphatic polyesters based on aliphatic dicarboxylic acids and aliphatic diols (referred to as (c2-c)), and mixtures thereof.

[0187] Polyhydroxyalkanoates are also referred to as polyhydroxy fatty acids and are understood in the context of the present invention to mean those containing monomers having a chain length of at least 3 carbon atoms in the polymer backbone. Therefore, in the context of the present invention, polylactic acid and polyglycolic acid (also referred to as polyglycolic acid) are not polyhydroxyalkanoates. In the context of the present invention, polycaprolactone (PCL) is also not understood as a polyhydroxyalkanoate.

[0188] According to the invention, it is preferred to use at least one polyhydroxyalkanoate comprising repeating monomer units of formula (1)

[0189] [—O—CHR—(CH2) m —CO—] (1)

[0190] wherein R is hydrogen or a linear or branched alkyl group having 1 to 20, preferably 1 to 16, preferably 1 to 6 carbon atoms, and m=a number from 1 to 18, preferably 1, 2, 3, 4, 5 and 6; and / or a homopolymer of 2-hydroxybutyric acid.

[0191] The polyhydroxy fatty acids include homopolymers, ie, polyhydroxy fatty acids composed of the same hydroxy fatty acid monomers, and copolymers, ie, polyhydroxy fatty acids composed of different hydroxy fatty acid monomers.

[0192] The polyhydroxy fatty acids may be used alone or in any combination.

[0193] In the context of the present invention, polyhydroxy fatty acids generally have a molecular weight Mw of 5,000 to 1,000,000, particularly 30,000 to 1,000,000, in particular 70,000 to 1,000,000, preferably 100,000 to 1,000,000 or 200,000 to 600,000 and / or a melting point in the range of 100 to 190°C.

[0194] The polyhydroxy fatty acids preferably have a relative humidity of 1 cm 3 / 10min to 50cm 3 / 10min, preferably within 1.5cm 3 / 10min to 40cm 3 / 10min, more preferably within 2cm 3 / 10min to 30cm 3 The melt volume rate (MVR) is in the range of 10 min / 10 min.

[0195] In one embodiment of the present invention, at least one polyhydroxyalkanoate is selected from the group consisting of:

[0196] - Poly(3-hydroxypropionate) (P3HP);

[0197] - Polyhydroxybutyrate (PHB);

[0198] - Polyhydroxyvalerate (PHV);

[0199] - polyhydroxycaproate (PHHx);

[0200] - polyhydroxyoctanoate (PHO);

[0201] - polyhydroxyoctadecanoate (PHOd);

[0202] - copolyesters of hydroxybutyric acid and at least one monomer selected from the group consisting of 3-hydroxypropionic acid, hydroxyvaleric acid, hydroxycaproic acid, hydroxyoctanoic acid and hydroxyoctadecanoic acid;

[0203] - copolyesters of hydroxyvaleric acid and at least one monomer selected from the group consisting of 3-hydroxypropionic acid, hydroxycaproic acid, hydroxyoctanoic acid and hydroxyoctadecanoic acid; and

[0204] - Copolyesters of hydroxycaproic acid and at least one monomer selected from the group consisting of 3-hydroxypropionic acid, hydroxyoctanoic acid and hydroxyoctadecanoic acid.

[0205] Suitable polyhydroxybutyrates (PHBs) may be selected from the group consisting of poly (3-hydroxybutyrate) (P3HB), poly (4-hydroxybutyrate) (P4HB) and copolymers of at least 3 hydroxybutyric acids selected from the group consisting of 3-hydroxybutyric acid and 4-hydroxybutyric acid. Further suitable are copolymers of 3-hydroxybutyric acid and 4-hydroxybutyric acid. These copolymers are characterized by the following abbreviation: [P (3HB-co-4HB)], wherein 3HB is 3-hydroxybutyrate and 4HB is 4-hydroxybutyrate.

[0206] Poly(3-hydroxybutyrate) is available, for example, from Tianan under the trade name In particular, Metabolix has developed poly-3-hydroxybutyrate-co-4-hydroxybutyrate. They are now commercialized by CJ CheilJedang.

[0207] Suitable polyhydroxyvalerate (PHV) may be selected from the group consisting of:

[0208] - homopolymers of 3-hydroxyvaleric acid [= poly(3-hydroxyvalerate) (P3HV)];

[0209] - homopolymers of 4-hydroxyvaleric acid [= poly(4-hydroxyvalerate) (P4HV)];

[0210] - homopolymers of 5-hydroxyvaleric acid [= poly(5-hydroxyvalerate) (P5HV)];

[0211] - homopolymers of 3-hydroxymethylvaleric acid [= poly(3-hydroxymethylvalerate) (P3MHV)]; and

[0212] - A copolymer of at least 3 hydroxyvaleric acids selected from the group consisting of 3-hydroxyvaleric acid, 4-hydroxyvaleric acid, 5-hydroxyvaleric acid and 3-hydroxymethylvaleric acid.

[0213] Suitable polyhydroxyhexanoate (PHHx) may be selected from the group consisting of poly(3-hydroxyhexanoate) (P3HHx), poly(4-hydroxyhexanoate) (P4HHx), poly(6-hydroxyhexanoate) (P6HHx) and copolymers of at least 3 hydroxyhexanoic acids selected from the group consisting of 3-hydroxyhexanoic acid, 4-hydroxyhexanoic acid and 6-hydroxyhexanoic acid.

[0214] Suitable polyhydroxyoctanoate (PHO) may be selected from the group consisting of poly(3-hydroxyoctanoate) (P3HO), poly(4-hydroxyoctanoate) (P4HO), poly(6-hydroxyoctanoate) (P6HO) and copolymers of at least 3 hydroxyoctanoic acids selected from the group consisting of 3-hydroxyoctanoic acid, 4-hydroxyoctanoic acid and 6-hydroxyoctanoic acid.

[0215] Suitable copolyesters of hydroxybutyric acid and at least one monomer selected from the group consisting of 3-hydroxypropionic acid, hydroxyvaleric acid, hydroxycaproic acid, hydroxyoctanoic acid and hydroxyoctadecanoic acid may be selected from the group consisting of:

[0216] -Copolyester of 4-hydroxybutyric acid and 3-hydroxyvaleric acid [P(4HB-co-3HV)];

[0217] -Copolyester of 3-hydroxybutyric acid and 3-hydroxyvaleric acid [P(3HB-co-3HV)];

[0218] -Copolyester of 4-hydroxybutyric acid and 3-hydroxyhexanoic acid [P(4HB-co-3HHx)];

[0219] -Copolyesters of 3-hydroxybutyric acid and 3-hydroxyhexanoic acid [P(3HB-co-3HHx)];

[0220] -Copolyester of 4-hydroxybutyric acid and 3-hydroxyoctanoic acid [P(4HB-co-3HO)];

[0221] - copolyester of 3-hydroxybutyric acid and 3-hydroxyoctanoic acid [P(3HB-co-3HO)]; and

[0222] -Copolyesters of 4-hydroxybutyric acid and 3-hydroxyoctadecanoic acid [P(4HB-co-3HOD)] and copolyesters of 3-hydroxybutyric acid and 3-hydroxyoctadecanoic acid [P(3HB-co-3HOd)].

[0223] Preference is given to using poly-3-hydroxybutyrate-co-3-hydroxyhexanoate in which the proportion of 3-hydroxyhexanoate is 1 to 20 mol %, preferably 3 to 15 mol %, based on the total amount of polyhydroxy fatty acids. Such poly-3-hydroxybutyrate-co-3-hydroxyhexanoate [P(3HB-co-3HHx] is known from Kaneka and is available under the trade name Aonilex TM X131A and Aonilex TM X151A was commercially available.

[0224] Suitable copolyesters of hydroxyvaleric acid are preferably copolyesters of 4-hydroxyvaleric acid and / or 3-hydroxyvaleric acid with at least one monomer selected from the group consisting of 3-hydroxypropionic acid, hydroxycaproic acid, hydroxyoctanoic acid, in particular 3-hydroxyoctanoic acid and hydroxyoctadecanoic acid.

[0225] Suitable copolyesters of hydroxycaproic acid are preferably copolyesters of 3-hydroxycaproic acid and at least one monomer selected from the group consisting of 3-hydroxypropionic acid and hydroxyoctanoic acid, preferably 3-hydroxyoctanoic acid and hydroxyoctadecanoic acid.

[0226] In one embodiment of the present invention, at least one polyhydroxyalkanoate is selected from the group consisting of: poly(3-hydroxypropionate) (P3HP); copolymers of at least three hydroxybutyric acids selected from the group consisting of 3-hydroxybutyric acid and 4-hydroxybutyric acid; copolymers of 3-hydroxybutyric acid and 4-hydroxybutyric acid; poly(3-hydroxyvalerate) (P3HV); poly(4-hydroxyvalerate) (P4HV); poly(5-hydroxyvalerate) (P5HV); poly(3-hydroxymethylvalerate) (P3MHV); at least three selected from the group consisting of 3-hydroxyvaleric acid, 4-hydroxyvaleric acid, 5-hydroxyvaleric acid and 3 -hydroxymethyl valeric acid; poly (3-hydroxyhexanoate) (P3HHx); poly (4-hydroxyhexanoate) (P4HHx); poly (6-hydroxyhexanoate) (P6HHx); copolymers of at least three hydroxyhexanoic acids selected from the group consisting of 3-hydroxyhexanoic acid, 4-hydroxyhexanoic acid and 6-hydroxyhexanoic acid; poly (3-hydroxyoctanoate) (P3HO); poly (4-hydroxyoctanoate) (P4HO); poly (6-hydroxyoctanoate) (P6HO); copolymers of at least three hydroxyoctanoic acids selected from the group consisting of 3-hydroxyoctanoic acid, 4-hydroxyoctanoic acid and 6-hydroxyoctanoic acid. copolymers; poly(3-hydroxyoctanoate) (P3HO); poly(4-hydroxyoctanoate) (P4HO); poly(6-hydroxyoctanoate) (P6HO); copolymers of at least three hydroxyoctanoic acids selected from the group consisting of 3-hydroxyoctanoic acid, 4-hydroxyoctanoic acid and 6-hydroxyoctanoic acid; copolyesters of 2-hydroxybutyric acid and at least one monomer selected from the group consisting of 3-hydroxypropionic acid, hydroxyvaleric acid, hydroxycaproic acid, hydroxyoctanoic acid and hydroxyoctadecanoic acid; copolyesters of 4-hydroxybutyric acid and 3-hydroxyoctanoic acid [P(4HB-co-3HO)], copolyesters of 3-hydroxybutyric acid and 3-hydroxyoctanoic acid [P copolyesters of hydroxyvaleric acid, especially 3-hydroxyvaleric acid or 4-hydroxyvaleric acid, and at least one monomer selected from the group consisting of 3-hydroxypropionic acid, hydroxycaproic acid, hydroxyoctanoic acid and hydroxyoctadecanoic acid; copolyesters of 3-hydroxycaproic acid and at least one monomer selected from the group consisting of 3-hydroxypropionic acid, hydroxyoctanoic acid, preferably 3-hydroxyoctanoic acid and hydroxyoctadecanoic acid.

[0227] Suitable polyhydroxyalkanoates generally have a molecular weight Mw of 100 000 g / mol to 1 000 000 g / mol and preferably 300 000 g / mol to 600 000 g / mol, determined by GPC in HFIP as solvent relative to a narrow distribution PMMA standard.

[0228] Polylactide, also known as polylactic acid, is a thermoplastic polyester with a main chain chemical formula of (C3H4O2) n or [-C(CH3)HC(=O)O-] n , formally obtained by dehydration condensation of lactic acid C(CH3)(OH)HCOOH. It can also be prepared by ring-opening polymerization of lactide [-C(CH3)HC(=O)O-]2 (cyclic dimer of basic repeating unit). Based on the total weight of PLA, suitable PLA contains at least 90% by weight, preferably greater than 95% by weight of lactic acid repeating units.

[0229] In particular, suitable polylactides have a melting point, determined by DSC, of ​​less than 240° C., in particular less than 230° C., especially less than 220° C.

[0230] In particular, suitable polylactides have an average molecular weight determined by GPC of greater than 50,000 Daltons, in particular greater than 60,000 Daltons, especially greater than 65,000 Daltons. Preference is given to a range of 50,000 Daltons to 120,000 Daltons.

[0231] The polylactide preferably has a relative humidity of 100% by weight according to EN ISO 1133 (190° C., 2.16 kg weight) at 1 cm 3 / 10min to 50cm 3 / 10min, preferably within 2cm 3 / 10min to 30cm 3 / 10min, more preferably within 3cm 3 / 10min to 20cm 3 The melt volume rate (MVR) is in the range of 10 min / 10 min.

[0232] Preferred polylactides are available from NatureWorks under the trade name 2003D, 4043D, and 4060D were commercially available.

[0233] In a specific embodiment, the aliphatic polyester (c2) is selected from the group consisting of polyhydroxyalkanoates and polylactic acid and mixtures thereof, preferably selected from the group consisting of polyhydroxyalkanoates and mixtures thereof.

[0234] In a particular set of embodiments, the aliphatic polyester (c2) is selected from the group consisting of polylactides.

[0235] In another specific group of embodiments, the aliphatic polyester (c2) is selected from the group consisting of polyhydroxyalkanoates.

[0236] Other examples of aliphatic polyesters (c2), referred to as (c2-c) and different from (c2-a) and (c2-b), are based on aliphatic dicarboxylic acids and aliphatic diols.

[0237] Examples of aliphatic dicarboxylic acids and ester-forming derivatives include, but are not limited to, oxalic acid, malonic acid, succinic acid, 2-methylsuccinic acid, glutaric acid, 2-methylglutaric acid, 3-methylglutaric acid, α-ketoglutaric acid, adipic acid, pimelic acid, azelaic acid, sebacic acid, tridecanedioic acid, fumaric acid, 2,2-dimethylglutaric acid, suberic acid, diglycolic acid, oxaloacetic acid, glutamic acid, aspartic acid, itaconic acid and maleic acid, their anhydrides and their C1-C4-alkyl esters. These dicarboxylic acids or their ester-forming derivatives may be used alone or in the form of a mixture of two or more thereof.

[0238] Preference is given to using succinic acid, adipic acid, azelaic acid, sebacic acid, tridecanedioic acid or their corresponding ester-forming derivatives or mixtures thereof. Particular preference is given to using succinic acid, adipic acid or sebacic acid or their corresponding ester-forming derivatives or mixtures thereof. Succinic acid, azelaic acid, sebacic acid and tridecanedioic acid also have the advantage of being obtainable from renewable raw materials.

[0239] Thus, other examples of aliphatic polyesters are, in particular but not limited to, aliphatic polyesters in which the aliphatic dicarboxylic acid is selected from succinic acid, adipic acid, azelaic acid, sebacic acid, tridecanedioic acid and mixtures thereof. Particularly preferred are succinic acid, adipic acid and sebacic acid and mixtures thereof.

[0240] Examples of aliphatic diols as described above in component c1-iii. Preferred are C2-C6-alkanediols, in particular 1,3-propylene glycol and / or 1,4-butanediol, particularly preferred are 1,3-propylene glycol, 1,4-butanediol and mixtures thereof; even more preferred is 1,4-butanediol.

[0241] Therefore, other examples of aliphatic polyesters (c2) are specifically poly(butylene succinate-co-adipate), poly(butylene succinate), poly(butylene sebacate), poly(butylene succinate-co-sebacate) and mixtures thereof, especially poly(butylene succinate-co-adipate), poly(butylene succinate), poly(butylene succinate-co-sebacate) and mixtures thereof.

[0242] Aliphatic polyesters (c2-c) can be used, for example, as Obtained from commercial purchase.

[0243] Preferred aliphatic polyesters (c2-c) generally have a number average molecular weight Mn determined by GPC in the range of 5000 g / mol to 100000 g / mol, in particular in the range of 10000 g / mol to 75000 g / mol, especially in the range of 15000 g / mol to 60000 g / mol.

[0244] Preferred aliphatic polyesters (c2-c) generally have a melting point, determined by DSC, in the range of 50 to 130° C., particularly in the range of 55 to 125° C., especially in the range of 65 to 120° C.

[0245] In particular, aliphatic polyesters (c2-c), for example partially or highly crystalline and solid polyester polyols. Such aliphatic polyesters have a hydroxyl number in the range of 10 mg KOH / g to 34 mg KOH / g, in particular in the range of 27 mg KOH / g to 34 mg KOH / g, in particular in the range of 28 mg KOH / g to 34 mg KOH / g, determined according to DIN EN ISO 2114:2002-6.

[0246] Suitable aliphatic polyesters (c2-c) have an acid number, determined to DIN EN ISO 2114, of at most 3 mg KOH / g, in particular of at most 2 mg KOH / g, in particular of at most 1.7 mg KOH / g.

[0247] In a preferred group of embodiments, component (c) comprises a combination of at least one aliphatic-aromatic polyester (c1) and at least one aliphatic polyester (c2).

[0248] In this combination, the weight ratio of component (c1) to component (c2) is generally in the range of 10:1 to 1:10, particularly in the range of 5:1 to 5:1, and especially in the range of 3:1 to 1:3. Therefore, in a particularly preferred embodiment, component (c1) comprises

[0249] 9 to 91 wt. %, in particular 20 to 80 wt. %, especially 25 to 75 wt. %, preferably 50 wt. %, of at least one component (c1), based on the total weight of component (c); and

[0250] 9 to 91 wt. %, in particular 20 to 80 wt. %, especially 25 to 75 wt. %, of at least one component (c2), based on the total weight of component (c).

[0251] In a specific set of embodiments, component (c) comprises

[0252] - 90% to 9% by weight, in particular 20% to 80% by weight, and especially 25% to 75% by weight, based on the total weight of component (c), of at least one component (c1) selected from the group consisting of poly(butylene adipate-co-terephthalate) (PBAT), poly(butylene azelaate-co-terephthalate) (PBAzeT), poly(butylene sebacate-co-terephthalate) (PBSeT), poly(butylene sebacate-co-terephthalate) (PBSeT), poly(butylene sebacate-co-terephthalate) (PBSeT), poly(butylene adipate-co-terephthalate) (PBAT), poly(butylene azelaate-co-terephthalate) (PBAT), poly(butylene azelaate-co-terephthalate) (PBAT), poly(butylene sebacate-co-terephthalate) (PBSeT), poly(butylene sebacate-co-terephthalate) (PBSeT), poly(butylene sebacate-co-terephthalate) (PBSeT), poly(butylene sebacate-co-terephthalate) (PBSeT), poly(butylene adipate-co-terephthalate) (PBSeT), poly(butylene adipate-co-terephthalate) (PBAT), poly(butylene azela ... poly(butylene sebacate-co-succinate-co-terephthalate) (PBSeAT), poly(butylene sebacate-co-succinate-co-terephthalate) (PBSeST), poly(butylene azelaate-co-adipate-co-terephthalate), poly(butylene azelaate-co-succinate-co-terephthalate), poly(butylene adipate-co-furanate) and poly(butylene sebacate-co-furanate), poly(butylene azelaate-co-furanate) and mixtures thereof; and

[0253] - 9 to 90% by weight, in particular 20 to 80% by weight, especially 25 to 75% by weight, based on the total weight of component (c), of at least one component (c2) selected from the group consisting of polyhydroxyalkanoates (c2-a) and polylactic acid (c2-b) and mixtures thereof, preferably selected from the group consisting of polyhydroxyalkanoates (c2-a) or also preferably selected from the group consisting of polylactic acid (c2-b).

[0254] The thermoplastic polymer blends of the present invention generally have a relative humidity of 10 % at 1 cm 3 / 10min to 30cm 3 / 10min, preferably within 1cm 3 / 10min to 15cm 3 / 10min, more preferably within 2cm 3 / 10min to 10cm 3 The melt volume rate (MVR) is in the range of 10 min / 10 min.

[0255] In particular, the polymer blend of the present invention comprises

[0256] - 5 to 70% by weight, in particular 7 to 65% by weight, especially 15 to 60% by weight, of a combination of at least one thermoplastic hydrophobically modified starch (a) and at least one native starch (b), based on the total weight of the blend in anhydrous form;

[0257] 30% to 95% by weight, in particular 35% to 93% by weight and especially 40% to 85% by weight, based on the total weight of the blend in anhydrous form, of at least one polyester (c).

[0258] Preferably, the polymer blend of the present invention comprises

[0259] 2 to 30% by weight, in particular 3 to 28% by weight and especially 5 to 25% by weight, based on the total weight of the blend in anhydrous form, of at least one thermoplastic hydrophobically modified starch (a);

[0260] 5 to 63% by weight, in particular 7 to 62% by weight, especially 10 to 55% by weight, based on the total weight of the blend in anhydrous form, of at least one thermoplastic native starch (b);

[0261] - 35% to 93% by weight, in particular 35% to 90% by weight, especially 40% to 85% by weight, based on the total weight of the blend in anhydrous form, of at least one polyester (c); which is preferably selected from the group consisting of polyesters (c1) and (c2); more preferably selected from the group consisting of polyesters (c1) or from a combination of at least one (c1) and at least one (c2).

[0262] In a specific set of embodiments, the polymer blend of the present invention comprises

[0263] 2 to 30% by weight, in particular 3 to 28% by weight and especially 5 to 25% by weight, based on the total weight of the blend in anhydrous form, of at least one thermoplastic hydrophobically modified starch (a);

[0264] 5 to 63% by weight, in particular 7 to 62% by weight, especially 10 to 55% by weight, based on the total weight of the blend in anhydrous form, of at least one thermoplastic native starch (b);

[0265] - 30% to 95% by weight, in particular 35% to 90% by weight, and especially 40% to 85% by weight, based on the total weight of the blend in anhydrous form, of at least one polyester (c1) selected from the group consisting of poly(butylene adipate-co-terephthalate) (PBAT), poly(butylene azelaic acid-co-terephthalate) (PBAzeT), poly(butylene sebacate-co-terephthalate) (PBSeT), poly(butylene sebacate-co-adipate-co-terephthalate) (PBSeAT), poly(butylene sebacate-co-succinate-co-terephthalate) (PBSeST), poly(butylene azelaic acid-co-adipate-co-terephthalate), poly(butylene azelaic acid-co-succinate-co-terephthalate) and mixtures thereof.

[0266] In another specific embodiment, the polymer blend of the present invention comprises

[0267] 2 to 30% by weight, in particular 3 to 28% by weight and especially 5 to 25% by weight, based on the total weight of the blend in anhydrous form, of at least one thermoplastic hydrophobically modified starch (a);

[0268] 5 to 63% by weight, in particular 7 to 62% by weight and especially 10 to 55% by weight, based on the total weight of the blend in anhydrous form, of at least one thermoplastic native starch (b);

[0269] - 30% to 95% by weight, in particular 35% to 90% by weight, and especially 40% to 85% by weight, based on the total weight of the blend in anhydrous form

[0270] o at least one polyester (c1) selected from the group consisting of poly(butylene adipate-co-terephthalate) (PBAT), poly(butylene azelaate-co-terephthalate) (PBAzeT), poly(butylene sebacate-co-terephthalate) (PBSeT), poly(butylene sebacate-co-adipate-co-terephthalate) (PBSeAT), poly(butylene sebacate-co-succinate-co-terephthalate) (PBSeST), poly(butylene azelaate-co-adipate-co-terephthalate), poly(butylene azelaate-co-succinate-co-terephthalate), poly(butylene adipate-co-furanate) and poly(butylene sebacate-co-furanate), poly(butylene azelaate-co-furanate) and mixtures thereof; and

[0271] o At least one polyester (c2) selected from the group consisting of polyhydroxyalkanoates (c2-a) and polylactic acid (c2-b); preferably selected from the group consisting of (c2-a) or (c2-b).

[0272] In another specific embodiment, the polymer blend of the present invention comprises

[0273] 2 to 30% by weight, in particular 3 to 28% by weight and especially 5 to 25% by weight, based on the total weight of the blend in anhydrous form, of at least one thermoplastic hydrophobically modified starch (a);

[0274] 5 to 63% by weight, in particular 7 to 62% by weight and especially 10 to 55% by weight, based on the total weight of the blend in anhydrous form, of at least one thermoplastic native starch (b);

[0275] - 30% to 95% by weight, in particular 35% to 90% by weight, especially 40% to 85% by weight, based on the total weight of the blend in anhydrous form, of a combination of:

[0276] o at least one polyester (c1) selected from the group consisting of poly(butylene adipate-co-terephthalate) (PBAT), poly(butylene azelaate-co-terephthalate) (PBAzeT), poly(butylene sebacate-co-terephthalate) (PBSeT), poly(butylene sebacate-co-adipate-co-terephthalate) (PBSeAT), poly(butylene sebacate-co-succinate-co-terephthalate) (PBSeST), poly(butylene azelaate-co-adipate-co-terephthalate), poly(butylene azelaate-co-succinate-co-terephthalate), poly(butylene adipate-co-furanate) and poly(butylene sebacate-co-furanate), poly(butylene azelaate-co-furanate) and mixtures thereof; and

[0277] o At least one aliphatic polyester (c2-c) selected from the group consisting of poly(butylene succinate-co-adipate), poly(butylene succinate), poly(butylene sebacate), poly(butylene succinate-co-sebacate) and mixtures thereof, in particular poly(butylene succinate-co-adipate), poly(butylene succinate), poly(butylene succinate-co-sebacate) and mixtures thereof.

[0278] In addition to the above-mentioned components (a), (b) and (c), the polymer blend may also contain one or more additional components (d) different from components (a), (b) and (c). These components (d) are generally selected from the group of additives known for polymer blends, in particular polymer blends based on polyesters and starches. These additives include, but are not limited to, the following components (d1), (d2) and (d3):

[0279] (d1) one or more fillers as component (d1); and / or

[0280] (d2) one or more additives as component (d2), such as stabilizers, nucleating agents, lubricants and release agents, surfactants, waxes, antistatic agents, antifogging agents, dyes, pigments, UV absorbers, UV stabilizers, organic acids and mixtures thereof;

[0281] (d3) Additives other than those mentioned in (d2), such as organic acids and fatty acid esters.

[0282] The total amount of component d) can be up to 70% by weight, in particular up to 60% by weight and especially up to 50% by weight, based on the total weight of the blend.

[0283] In one embodiment, the thermoplastic polymer blend optionally comprises 0% to 50% by weight (if present), e.g., 0% to 50% by weight, particularly 0.1% to 40% by weight, especially 0.2% to 35% by weight, of one or more fillers (component (d1)), based on the total weight of the blend in anhydrous form. Suitable fillers include, but are not limited to, natural fibers, wood flour and / or inorganic fillers selected from the group consisting of chalk, precipitated calcium carbonate, graphite, gypsum, conductive carbon black, iron oxide, calcium chloride, dolomite, kaolin, silicon dioxide (quartz), sodium carbonate, titanium dioxide, silicates, wollastonite, mica, montmorillonite, talc, glass fibers and mineral fibers, and are added.

[0284] Natural fibers are understood to mean, for example, cellulose fibers, hemp fibers, sisal, kenaf, jute, flax, abacca, coconut fibers or cordenka fibers.

[0285] As preferred fibrous fillers, mention may be made of glass fibers, carbon fibers, aramid fibers, potassium titanate fibers and natural fibers, glass fibers as E-glass being particularly preferred. These can be used as rovings or, in particular, as cut glass in commercially available form. These fibers generally have a diameter of 3 μm to 30 μm, preferably 6 μm to 20 μm and particularly preferably 8 μm to 15 μm. The fiber length in the compound is generally 20 μm to 1000 μm, preferably 180 μm to 500 μm and particularly preferably 200 μm to 400 μm.

[0286] In another embodiment, the thermoplastic polymer blend optionally comprises 0.1% to 2.5% by weight, in particular 0.3% to 2.3% by weight, especially 0.5% to 2% by weight, based on the total weight of the blend in anhydrous form, of at least one component (d2), which is generally selected from the group consisting of stabilizers, nucleating agents, lubricants and mold release agents, surfactants, waxes, antistatic agents, antifogging agents, dyes, pigments, UV absorbers, UV stabilizers, other plastic additives typically used in polyester blends.

[0287] Suitable nucleating agents include, but are not limited to, polybutylene terephthalate, N,N'-ethylenebisstearamide, zinc phenylphosphonate, graphite, talc, chalk, precipitated calcium carbonate, kaolin, quartz sand, or silicates.

[0288] Particularly preferably, the thermoplastic polymer blend comprises 0.0% to 1% by weight, in particular 0.05% to 0.5% by weight and especially 0.1% to 0.35% by weight, based on the total weight of the polymer blend in anhydrous form, of at least one lubricant.

[0289] Suitable lubricants include, but are not limited to, fatty acid amides, such as stearamide.

[0290] Suitable mold release agents include, but are not limited to, stearates (particularly calcium stearate).

[0291] Suitable surfactants include, but are not limited to, polysorbates, palmitates, and laurates.

[0292] Suitable waxes include, but are not limited to, erucamide, stearamide, behenamide, beeswax or beeswax esters, plant-based waxes such as candelilla wax or carnauba wax.

[0293] Of course, any other conventional additives for starch blends not mentioned so far can be included. These additives are referred to as additives (d3). For example, the blend may include one or more additives (d3) selected from organic acids and fatty acid esters, such as those described in EP0947559 and by Zhang et al., Polm.Adv.Technol.2018, pages 1-11. Based on the total weight of the blend in anhydrous form, these additives are typically used in a concentration of 0% to 2% by weight, particularly 0.01% to 2% by weight.

[0294] In particular, organic acids may be added to the blends of the present invention. Suitable examples of these acids include, but are not limited to, hydroxycarboxylic acids such as malic acid, lactic acid, tartaric acid, citric acid, or mixtures thereof. If present, the organic acid is typically used in a concentration of 0% to 0.5% by weight, particularly 0.01% to 0.45% by weight, and preferably 0.05% to 0.3% by weight, based on the total weight of the blend in anhydrous form.

[0295] The above-mentioned fillers and additives (d) may also be fed into the extruder separately from the components (a) to (c) in any order or fed into the extruder together with the components (a) to (c).

[0296] In one embodiment, additives (d3), in particular organic acids, such as malic acid, lactic acid, tartaric acid, citric acid or mixtures thereof, may already be incorporated into component (a). However, the above amounts, based on the total weight of component (a), also apply to this embodiment.

[0297] In particular, the polymer blend optionally comprises

[0298] (d1) 0 to 50% by weight (if present), for example 0.1 to 50% by weight, in particular 0.1 to 40% by weight and especially 0.2 to 35% by weight, of filler (component (d1)), based on the total weight of the blend in anhydrous form;

[0299] (d2) 0 to 2 wt. % (if present), e.g. 0.01 to 2 wt. %, in particular 0.01 to 1 wt. % and especially 0.05 to 0.5 wt. %, based on the total weight of the blend in anhydrous form, of a component (d2), in particular selected from stabilizers, nucleating agents, lubricants and release agents, surfactants, waxes, antistatic agents, antifogging agents, dyes, pigments, UV absorbers, UV stabilizers and combinations thereof; preferably selected from lubricants; and / or

[0300] (d3) 0 to 0.5 wt. % (if present), 0.01 to 0.5 wt. %, in particular 0.01 to 0.45 wt. % and especially 0.05 to 0.3 wt. % of the above-mentioned additives (d3), in particular an organic acid, preferably selected from the group consisting of malic acid, lactic acid, tartaric acid, citric acid and mixtures thereof, based on the total weight of the blend in anhydrous form.

[0301] In one set of embodiments, components (d1), (d2) and / or (d3) are incorporated into the polymer blend during and / or after preparation of the polymer blend.

[0302] In another embodiment, components (d1) and / or (d2) are already incorporated into polyester (c). However, the above amounts of components (d1) and (d2), based on the total weight of polyester (c), also apply to this embodiment.

[0303] The thermoplastic polymer blends of the present invention are prepared from the individual components by known methods similar to those described in, for example, EP 792 309, US 5,883,199, EP 906367A1, US 2011 / 0177275A1 and EP 2467418A1. For example, all components of the mixture can be mixed in a mixing device known to those skilled in the art (e.g., a kneader or an extruder) at elevated temperatures (e.g., 120° C. to 300° C.) in one process step.

[0304] The polymer blends of the present invention can be used as a dry blend or as a compound.

[0305] In particular, the process for preparing a thermoplastic polymer blend as defined herein comprises the following steps:

[0306] (i) providing at least one component (a) or a combination of hydrophobically modified starch and one or more plasticizers, said combination being converted in step (iv) into a thermoplastic hydrophobically modified starch (a);

[0307] (ii) providing at least one thermoplastic native starch (b) or a combination of a native starch and one or more plasticizers, and converting the combination into the thermoplastic native starch (b) in step (iv);

[0308] (iii) providing at least one polyester (c),

[0309] (iv) if necessary, providing one or more additional components selected from components (d1), (d2) and (d3);

[0310] (v) introducing and mixing the components provided in steps (i) to (iii) and optionally (iv).

[0311] In steps (i) to (iii), components (a) to (c) and, if desired, (d1), (d2) and / or (d3) are provided.

[0312] Preferably, in steps (i) to (ii), the thermoplastic starch components (a) and (b) are provided in a form in which they are already thermoplasticized.

[0313] Also preferably, in step (i) to (ii), thermoplastic starch components (a) and (b) can also be provided in the form that they do not yet have thermoplasticization and one or more plasticizers in combination. The combination of this not yet thermoplasticized starch and one or more plasticizers is converted into thermoplastic starch in step (v). Therefore, a combination of hydrophobically modified starch and one or more plasticizers can be provided in step (i), and this combination is converted into thermoplastic hydrophobically modified starch (a) in step (v). Equally, a combination of native starch and one or more plasticizers can be provided in step (ii), and this combination is converted into thermoplastic native starch (b) in step (v).

[0314] Suitable examples of the plasticizer of the combination are as described above.

[0315] In steps (iii) and (iv), at least one polyester (c) and, if desired, one or more additives and / or fillers (d) are provided. Suitable examples of additives and fillers (d1), (d2) and / or (d3) are as described above.

[0316] In step (v), the components provided in steps (i) to (iii) and optionally (iv) are provided and mixed in a suitable mixing device. In particular, step (v) is carried out in an extruder, especially in a twin-screw extruder. Preferably, step (v) is carried out using a single-stage method as described in US2022119598 A1. In a single-stage method, the plasticization of the starch component and the mixing with other polymer components or additives are carried out in the same machine or in two machines arranged in series in a process, and the operation here is mainly carried out in a twin-screw extruder.

[0317] In principle, the starting materials, i.e. components (a) to (c) and, if desired, (d), can be added in various ways: in direct addition, all starting materials, e.g. starch, polymers or optional further additives and solid plasticizers form the initial charge in zone 1, and / or liquid plasticizers, e.g. polyols and / or water, are then added in downstream zones (e.g. US 2011 / 0177275 A1).

[0318] EP 906367 A1 and EP 2467418 A1 disclose that starch is first plasticized with a plasticizer at a temperature above 140° C. The resulting hot plasticized starch is devolatilized, thereby substantially removing water. Only then is the additional polymer added in molten or granular solid form.

[0319] A common feature of all the processes described in the prior art is that gelatinization / plasticization of the starch takes place shortly after the addition of the plasticizer at a temperature above the gelatinization temperature.

[0320] Gelatinization, i.e. digestion of starch granules, occurs at a temperature that depends primarily on the properties of the starch used, in particular its water content, as well as the amount and structure of the plasticizer and its water content (see, e.g., Tan et al., Carbohydrate Polymers 2004, 58, 191-204; Taghizadeh & Favis, Carbohydrate Polymers 2013, 92, 1799-1808). In the range of plasticizer concentrations associated with starch blends, gelatinization of starch typically begins at temperatures above 70 to 100° C. Therefore, in step (v) of the process of the invention, the resulting extruder temperature is preferably set to less than 100° C., preferably less than 85° C., and particularly preferably less than 60° C.

[0321] In order to achieve sufficient and uniform wetting of starch by plasticizer at high production volume, a defined wetting section in the extruder is necessary. The wetting section is measured from the point where starch and plasticizer or a partial amount of plasticizer first meet each other to the point where the temperature of the extruder rises above the temperature at which starch begins to gelatinize (gelatinization temperature). The length of the wetting section in the extruder is generally 8D (i.e., 8×the diameter of the screw barrel), and is preferably at least 12D. If operated with two extruders arranged in series, the first extruder is generally used for the wetting of starch, and its length is generally 8D to 80D and preferably 12D to 60D. The additional residence time of starch together with the plasticizer results in a product containing only a very small amount of incompletely digested agglomerated starch particles. Economic considerations require that if two extruders are used, the wetting sections longer than 30D and 60D in a single extruder are relatively unimportant.

[0322] In embodiment A of the process of the invention, only conveying screw elements are installed in the wet section of the extruder. In this mode of operation, the polyester component (c) can be added at any desired point in the wet section; this point can also be in zone 1 at the inlet end of the extruder. Component (c) is preferably added in solid form.

[0323] In a preferred embodiment B, at least one, preferably two or more intensive mixing screw elements are installed in addition to the conveying screw elements in the wetting section of the extruder, which screw elements further promote uniform wetting of the starch with the plasticizer and again reduce the number of agglomerated starch particles in the end product. The expression "intensive mixing screw elements" refers, for example, to kneading blocks, toothed mixing elements or other shearing elements. In embodiment B, it has proven to be advantageous to add the polyester (c), preferably in solid form, only downstream of these intensive mixing screw elements, but upstream of the end of the wetting section of the extruder.

[0324] The effective wetting of starch by the plasticizer in embodiment B has proven successful, in particular in an operating mode with a high throughput of more than 100 kg / h, in particular more than 120 kg / h and particularly preferably more than 150 kg / h, in each case based on a twin screw extruder with a screw diameter of 45 mm and based on the water-free end product (starch blend). Based on the water-free end product, the throughput achieved in a twin screw extruder with a screw diameter of 65 mm is more than 400 kg / h, in particular more than 500 kg / h and particularly preferably more than 600 kg / h.

[0325] In particular, embodiment B is also suitable for producing starch blends with a very fine dispersion of the starch component in the polymer matrix, or indeed a co-continuous structure with a very fine lamellar structure. Surprisingly, good dispersion is achieved even in starch blends with a high content of starch component of more than 29%, in fact more than 39% and in fact especially more than 44%.

[0326] In both embodiments, it has been found to be advantageous to introduce the polyester (c) in solid form (e.g. as granules), in particular before the thermoplasticization of the starch component, i.e. at a temperature below the gelling point of the starch / plasticizer mixture, so that melting of the polyester and thermoplasticization of the starch component occur simultaneously in the subsequent melting zone.

[0327] In principle, the polyester (c) can be added at any desired point in the extruder. However, downstream of the addition of the polyester (c), there must be sufficient screw length to allow any necessary melting of the polyester (c) (if the polyester (c) is added in solid form) and to ensure mixing with the starch component (thermoplasticized or not yet thermoplasticized) and dispersion of the thermoplasticized starch component into the polymer matrix.

[0328] In order to provide any necessary melting of the polyester (c) and to digest, decompose and thermoplasticize the starch component and disperse it in the molten polymer, the internal temperature of the extruder is gradually increased along the plasticizing section to a temperature above 130° C. Preferably, the barrel temperature set in the plasticizing section (optionally increased to the discharge die of the extruder) starts at 90° C. and ends at 260° C., preferably ends at 230° C. and particularly preferably ends at 220° C., and wherein the temperature of the polymer melt is kept below 250° C., preferably below 240° C. and particularly preferably below 230° C. when discharged from the die.

[0329] The relatively low temperature operation mode has the following advantages: in the further process of the extrusion process, the mixing and homogenization of the melt is carried out in the presence of a large amount of water, usually 1% to 20% by weight, preferably 3% to 15% by weight, particularly preferably 5% to 10% by weight, based on the total amount of the anhydrous final product. Therefore, the starch component is very fully protected from any unfavorable thermal degradation involving discoloration. The high water content present at least at the beginning of the plasticizing section then promotes the uniform fine particle dispersion of starch in the polymer matrix. In addition, for example, by lateral devolatilization, the water content present in the mixture or preferably in the melt and produced by the water introduced by the starch component or by the plasticizer used or the plasticizer mixture or via a separate introduction is reduced, so that based on the starch blend, the content discharged from the extruder (at the discharge die) is less than 5%. In the case where the starch blend is granulated by an underwater granulator, it is advantageous that the water content at the discharge die is set to be less than 3% based on the starch blend. If a strand pelletizer is used, the water content is generally set to below 2%, preferably below 1%, based on the starch blend.

[0330] The blends of the invention can be used to prepare monolayer or multilayer films.The invention therefore also relates to a monolayer or multilayer film comprising at least one layer made from the blend defined herein.

[0331] The blends of the present invention may be formed into such monolayer or multilayer films using any known method including thermoplastic processes such as thermoforming, extrusion, coextrusion, film casting, film blowing, lamination, foaming using gas or chemical blowing agents, or any suitable combination thereof to produce the desired film.

[0332] The inventive blends described herein are particularly suitable for extrusion, coextrusion and blow molding of films having high tear strength.

[0333] Working Example

[0334] Starting Materials :

[0335] A1) F Blend C1200 - aliphatic-aromatic polyester from BASF with 3 cm 3 / 10min to 5cm 3 / 10min of MVR.

[0336] B1) Native corn starch, with a water content of about 12%.

[0337] C1) Neosorb 70 / 70 - a sorbitol solution with very low sensitivity to crystalline solids with a content of 70% and a sorbitol content of at least 50% (from Roquette).

[0338] D1) Agrana 8145 - hydrophobically modified thermoplastic starch (TPS), water content 5.7%, measured by infrared moisture analyzer at 130°C / 30 min (obtained from Agrana).

[0339] E1) is composed of 90% by weight Lubricant batch consisting of F Blend C1200 and 10 wt% stearamide from Croda

[0340] F1)PHBH TM Aonilex 151C - a biodegradable polyester based on vegetable oil from Kaneka

[0341] Description of the extruder used :

[0342] ZSK 45MC from Coperion 18 Co-rotating twin-screw extruder, diameter 45 mm, 15 electrically heatable and water-coolable barrel sections with a length to diameter ratio of L / D=60, with a wetted section of length 12D in which four kneading blocks are incorporated. Specific torque 18 Nm / cm 3 The polymer melt was pelletized using an underwater pelletizer from Gala.

[0343] Description of Blown Film Equipment :

[0344] The blown film equipment consisted of a single screw extruder with a diameter of 30 mm and a length of 25D, a spiral mandrel distributor with a diameter of 80 mm and a die gap of 0.8 mm. The blow-up ratio was typically 3.5, resulting in a lay-flat bubble width of about 440 mm.

[0345] analyze :

[0346] Determination of water content :

[0347] The residual moisture content was determined by Karl-Fischer titration method B2 according to EN ISO 15512:2019 at a heating temperature of 130°C using a Mettler-Toledo InMotion KF PRO oven autosampler.

[0348] Melt volume rate : Melt volume rate is determined according to EN ISO 1133 at the stated temperature and the stated weight and is expressed in cm 3 / 10min.

[0349] Average starch particle size : A sample was obtained from the film prepared in Example 2 at -80°C by microtome sectioning parallel to the extrusion direction. The sample was studied by atomic force microscopy on sections measuring 15×15 microns. The relatively hard TPS phase can be distinguished very easily from the relatively soft polymer phase and allows accurate determination of the blend morphology and the particle size of the starch particles dispersed in the polymer. Evaluation of the particle size gave an average particle size of 466 nanometers and a maximum particle size of only 1488 nanometers; this is evidence of a very fine particle dispersion of the starch particles in the polymer phase.

[0350] THF determination :THF determination is carried out by headspace GC-MS based on DIN 38407-F 43 2014-10 and LA-GC-013.071 (headspace GC-MS determination of volatile organic substances in low-fat foods). For this reason, a suitable amount of sample is dissolved in dimethylacetamide and THF-d8 is added as an internal standard. In Agilent HS GC / MS, the sample sealed in a glass headspace GC bottle is heated at 85°C for 30min in a headspace oven and then measured. Helium is used as a carrier gas. External calibration is performed on this value according to the recovery rate of the internal standard (THF-d8) and matrix effect control (Matrix Spike).

[0351] Film thickness :

[0352] The film thickness is determined from their known density (1.29 g / cm at 30% thermoplastic starch content). 3 , 1.31 g / cm at 40% thermoplastic starch content 3 ) and exact 100cm 2 The weight of the large film is calculated similarly to the method described in Appendix 3 of ASTM E252-06 for polyethylene.

[0353] Tensile test in longitudinal and transverse directions

[0354] Tensile tests were obtained from blown films under standard conditions (23°C, 50% relative humidity) according to ISO 527-3:2018. For each value, 5 specimens of type 2 with a width of 15 mm and a length of 150 mm were measured. The initial distance between the grips was 50 mm. The values ​​of the E-modulus were obtained at a test speed of 1 mm / min. The other parameters were obtained at a test speed of 125 mm / min.

[0355] Tear resistance (Pendulum Elmendorf test)

[0356] According to EN ISO 6383-2:2004, using the Thwing-Albert Instrument Company The tear resistance of the films was determined using an Electronic Elmendorf tear tester and constant radius film samples (43 mm tear length) under standard conditions (23° C., 50% relative humidity).

[0357] Embodiments 1 to 5 of the present invention (IE1 to 5) :

[0358] A co-rotating twin-screw extruder Coperion ZSK 45MC with a diameter of 45 mm was used according to the general procedure described in WO2020 / 156970. 18 and a 15×4D barrel to produce Examples 1 to 5, resulting in a total length L=60D.

[0359] All components are metered using separate gravimetric feeders or pumps. Native starch B1 is added to zone 1 of the extruder in powder form. Plasticizer C1 is added to zone 2 using a gravity-controlled gear pump. Starting material A1 as well as thermoplastic starch (TPS) D1 and lubricant E1 are added to zone 5 of the extruder in pellet form via a side feeder (ZS-B). Between the plasticizer addition point in zone 2 and the polymer addition point in zone 5, not only a conveying element is installed, but also 4 kneading blocks as mixing elements are installed. Excess water is removed in zones 11 and 14 via a 40mm lateral devolatilization unit (ZS EG 40). After removing the water, the melt is granulated using an underwater granulation device from Gala. In all cases, the water content is less than 0.5%, and subsequent drying is not required.

[0360] Temperature curve [℃]: 30-30-30-30-30-90-120-160-160-160-160-160-160-160-160-160-2x160 (2 flanges) -180 (starting valve) -180 (template).

[0361] Screw speed and throughput can be derived from the table.

[0362] Comparative Example 1 (CE1) :

[0363] Comparative Example 1 was prepared after the same steps as Inventive Examples 1 to 5, except that the hydrophobically modified thermoplastic starch D1 was not added.

[0364] Embodiment 6 of the present invention (IE6) :

[0365] Inventive Example 1 was carried out following the same steps as Inventive Examples 1 to 5, except that PHBH F1 was metered into zone 11 together with lubricant E1.

[0366] Comparative Example 2 (CE2) :

[0367] Comparative Example 2 was prepared following the same procedure as Inventive Example 6, except that the hydrophobically modified thermoplastic starch D1 was not added.

[0368] Comparative Example 3 (CE3) :

[0369] Comparative Example 3 was prepared following the same procedure as Inventive Example 6, except that the hydrophobically modified thermoplastic starch D1 was not added and a higher rotation rate was selected to increase shear.

[0370] Table 1 summarizes the relevant experimental conditions of IE1 to 5 and CE1, such as rotation rate, amount of A1 to E1 added, temperature profile, blow-up ratio and film thickness.

[0371] Table 2 summarizes the tensile test results for IE1 to 5 and CE1.

[0372] Table 3 summarizes the relevant experimental conditions of IE6 and CE2, such as the rotation rate, the amount of A1 to F1 added, the temperature profile, the blow-up ratio and the film thickness.

[0373] Table 4 summarizes the tensile test results for IE6 and CE2.

[0374] Table 1

[0375]

[0376] *nd: not determined; WC: water cooling

[0377] **Weight per unit area

[0378] Table 2

[0379]

[0380] *nd: not determined

[0381] Table 3

[0382]

[0383]

[0384] *nd: not determined; WC: water cooling

[0385] **Weight per unit area

[0386] Table 4

[0387]

[0388] *nd: not determined

[0389] Tables 1 to 4 show that films (IE1 to IE6) comprising a thermoplastic polymer blend of the invention containing a hydrophobically modified TSP have improved properties compared to comparative films (CE1 to CE3) not comprising a blend according to the invention. For example, the films of the invention of IE1 to IE6 containing a hydrophobically modified TSP have increased tensile stress, tensile strain, tear strength and tear propagation resistance and increased elongation at break or maximum tensile strength compared to comparative films of CE1 to CE3 not comprising a hydrophobically modified TSP (see Tables 2 and 4). In addition, in most cases, the films of the invention have an improved elastic modulus.

Claims

1. A thermoplastic polymer blend, comprising: (a) as component (a) at least one thermoplastic hydrophobically modified starch, (b) at least one thermoplastic natural starch as component (b), and (c) at least one thermoplastic polyester as component (c), the at least one thermoplastic polyester being selected from the group consisting of aliphatic polyesters, aliphatic-aromatic polyesters and mixtures thereof.

2. The blend according to claim 1, comprising the following relative amounts of components (a) and (b), based on the total weight of components (a) and (b), wherein the amounts of components (a) and (b) are calculated in their anhydrous form: (a) 1 to 70 wt. %, preferably 5 to 60 wt. %, especially 6 to 58 wt. % of the component (a) and (b) 30 to 99% by weight, preferably 40 to 95% by weight, especially 42 to 94% by weight of component (b).

3. The blend according to any one of claims 1 or 2, comprising the component (a) in an amount of 0.1 wt% to 35 wt%, based on the total weight of the blend in anhydrous form, wherein the amount of (a) is calculated as the anhydrous form of component (a).

4. The blend according to any one of the preceding claims, wherein component (a) is selected from the group consisting of: - thermoplastic starch hydrophobically modified with an epoxide from the group of aryl glycidyl ethers, alkyl-substituted aryl glycidyl ethers, aryl glycidyl esters, alkyl-substituted aryl glycidyl esters, alkyl glycidyl ethers and alkyl glycidyl esters and combinations thereof, -Thermoplastic starch hydrophobically modified with epoxidized vegetable oil - thermoplastic starch hydrophobically modified with fatty acids or their ester-forming derivatives, - thermoplastic starch hydrophobically modified with silane, - thermoplastic starch hydrophobically modified with anhydrides substituted with alkyl groups of dicarboxylic acids, - thermoplastic starch hydrophobically modified with isocyanate, and mixtures thereof.

5. The blend according to claim 4, wherein component (a) is selected from the group consisting of thermoplastic starch hydrophobically modified with epoxidized vegetable oil and mixtures thereof.

6. A blend according to any one of the preceding claims, wherein component (a) comprises one or more plasticizers selected from polyols.

7. The blend according to any one of the preceding claims, comprising: - 5% to 70% by weight, in particular 7% to 65% by weight, especially 15% to 60% by weight, of a combination of at least one thermoplastic hydrophobically modified starch (a) and at least one native starch (b), based on the total weight of the blend in anhydrous form, wherein the amounts of the components (a) and (b) are calculated in their anhydrous form; 30% to 95% by weight, in particular 5% to 93% by weight and especially 40% to 85% by weight, based on the total weight of the blend in anhydrous form, of at least one polyester (c).

8. The blend according to any one of the preceding claims, comprising: 2 to 30% by weight, in particular 3 to 28% by weight and especially 5 to 25% by weight, based on the total weight of the blend in anhydrous form, of at least one thermoplastic hydrophobically modified starch (a); 5 to 63% by weight, in particular 7 to 62% by weight, especially 10 to 55% by weight, based on the total weight of the blend in anhydrous form, of at least one thermoplastic native starch (b); 35% to 93% by weight, in particular 35% to 90% by weight and especially 40% to 85% by weight, based on the total weight of the blend in anhydrous form, of at least one polyester (c).

9. The blend according to any one of the preceding claims, wherein the component (c) is biodegradable.

10. The blend according to any one of the preceding claims, wherein component (c) comprises a combination of at least one aliphatic-aromatic polyester (c1) and at least one aliphatic polyester (c2).

11. The blend according to claim 10, wherein the aliphatic polyester (c2) is selected from the group consisting of polyhydroxyalkanoates and polylactic acid and mixtures thereof, preferably from the group consisting of polyhydroxyalkanoates.

12. The blend according to any one of the preceding claims, wherein component (c) comprises an aliphatic-aromatic polyester (c1) selected from the group consisting of: Aliphatic-aromatic polyesters comprising: c1-i) 25 to 70 mol %, preferably 35 to 65 mol % and in particular 40 to 60 mol %, based on the sum of the molar percentages of the repeating units c1-i and c1-ii, of at least one aliphatic C4-C 18 - repeating units c1-i of dicarboxylic acid; c1-ii) 30 to 75 mol %, preferably 35 to 65 mol % and in particular 40 to 60 mol % of repeating units c1-ii of terephthalic acid, based on the sum of the molar percentages of repeating units c1-i and c1-ii; and c1-iii) 98 to 102 mol %, 98 to 100 mol %, preferably 99 to 100 mol %, and in particular 100 mol %, based on the sum of the molar percentages of the repeating units c1-i and c1-ii, of repeating units c1-iii of at least one C2-C6-alkanediol, in particular 1,3-propanediol and / or 1,4-butanediol; and Aliphatic-aromatic polyesters comprising: c2-i) 20 to 60 mol %, preferably 20 to 50 mol % and in particular 20 to 40 mol %, based on the sum of the molar percentages of the repeating units c1-i and c1-ii', of at least one aliphatic C4-C 18 - repeating units c1-i of dicarboxylic acid; c2-ii) 40 to 80 mol %, preferably 50 to 80 mol % and in particular 60 to 80 mol % of repeating units c1-ii' of furandicarboxylic acid, based on the sum of the molar percentages of repeating units c1-i and c1-ii'; and c2-iii) 98 mol % to 100 102 mol %, preferably 99 mol % to 100 mol %, in particular 100 mol %, based on the sum of the molar percentages of the repeating units c1-i and c1-ii', of at least one C2-C6-alkanediol, in particular repeating units c1-iii of 1,3-propanediol and / or 1,4-butanediol.

13. The blend according to any of the preceding claims, wherein the component (c) comprises an aliphatic-aromatic polyester (c1) selected from the group consisting of poly(butylene adipate-co-terephthalate), poly(butylene azelaate-co-terephthalate), poly(butylene sebacate-co-terephthalate), poly(butylene sebacate-co-adipate-co-terephthalate), poly(butylene sebacate-co-succinate-co-terephthalate), poly(butylene azelaate-co-adipate-co-terephthalate), poly(butylene adipate-co-succinate-co-terephthalate), poly(butylene adipate-co-furanate) and poly(butylene sebacate-co-furanate), poly(butylene azelaate-co-furanate), and mixtures thereof.

14. A method for preparing a thermoplastic blend according to any one of the preceding claims, the method comprising the steps of: (i) providing at least one component (a) or a combination of hydrophobically modified starch and one or more plasticizers, said combination being converted in step (iv) into a thermoplastic hydrophobically modified starch (a); (ii) providing at least one thermoplastic native starch (b) or a combination of a native starch and one or more plasticizers, and converting the combination into the thermoplastic native starch in step (iv) (b)； (iii) providing at least one polyester (c); (iv) if necessary, providing one or more additional components in addition to components (a), (b) and (c); (v) introducing and mixing the components provided in steps (i) to (iii) and optionally (iv).

15. The method of claim 14, wherein step (v) is performed in an extruder.

16. A monolayer or multilayer film comprising at least one layer made from the blend according to any one of claims 1 to 13.

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