Thermoplastic biodegradable polymer material from renewable sources (TPE-BBPM)

Abstract

Thermoplastic biodegradable polymer material from renewable sources (TPE-BBPM) shows elastically reversible deformation of at least 80%, which is determined according to method M4 stated in the description of the invention, while the material contains at least one component A and at least one component B; while the component A is a biodegradable polymer from renewable sources, or a copolymer, which is amorphous or low-crystalline, while the total content of the crystalline phase of the component A is a maximum of 2 Wt %; and the component B is a biodegradable polymer from renewable sources or a copolymer, which is semi-crystalline, while the total content of the crystalline phase of the component B is at least 20 Wt %.

Description

Thermoplastic biodegradable polymer material from renewable sources (TPE-BBPM)Field of technologyThe present invention relates to biodegradable blended thermoplastic elastomers based on polymers from renewable sources.Prior artElastomers are polymers that show a high proportion of elastic (reversible) deformation under the action of external forces. In order to achieve an elastic effect, it is necessary that the internal structure of the polymer allows reversible deformation of the polymer chains in a wide but limited range. It is known from the literature and from general knowledge in the field of polymer chemistry and technology that in order for a polymer material to behave elastically and show a significant degree of elastically reversible deformation, it is necessary that, from a morphological point of view, it is a system of two continuous phases, where one phase is mobile (soft phase), which by itself shows a high rate of plastic flow at the application temperature and the other phase is immobile (hard phase), which by itself is not capable of plastic flow at the application temperature, while the polymeric material may be composed of one polymer or copolymer, or of several polymers or copolymers. Such a morphological arrangement prevents the plastic flow of the material and the deformation under the action of external forces is elastic, elastically reversible within the range of free mobility of the soft phase. If the polymer system of two or more polymers does not form two continuous phases and only a dispersion system is formed, then the material becomes: a) Purely plastic, without elastically reversible deformation, if the continuous phase is a soft component, b) Hard, inelastic, without elastically reversible deformation, if the continuous phase is a hard component, while the dispersed soft component usually improves the mechanical properties, particularly reduces the brittleness of the material, which is shown by increased impact strength, ductility, tensibility to breakage, the ductility (flexibility) and the like increases, but it does not result in an effect where the material is capable of elastically reversible deformation.A condition for the elasticity of a polymer material is the formation of a system of two continuous phases, which allow elastically reversible deformation of the material under the action of external forces, which is usually ensured as follows (alternatively):A) The material consists of a rubber polymer or polymers that are amorphous or low crystalline and whose Tg is below the application temperature at which elastic behavior is required, while a continuous network of transverse chemical bonds must be formed, preventing the irreversible translational flow of macromolecules. This condition is usually achieved by the so-called vulcanization of rubbers. Examples of such materials are mainly natural rubber (NR) or a whole range of synthetic rubbers (NR, SBR, BR, NBR, etc.), which usually contain a high proportion of unsaturated bonds, through which cross-links are formed by cross-linking reactions, most often with sulfur or sulfur compounds. In addition to sulfur vulcanization, it is possible to formcross-links with peroxides or other reactive substances capable of forming such links.OrB) The material consists of a block copolymer, one part of which has a Tg below the application temperature at which elastic behavior is required and the other part is at this temperature: a. Crystalline, while Tm is above the application temperature, or b. Amorphous with a Tg value above the temperature at which elastic behavior is required.In such a case, thermoplastic elastomers (TPE) are involved, while a typical example is triblock copolymers styrene - butadiene - styrene (SBS, or SEBS), where butadiene blocks or butadiene-ethylene blocks with low Tg ensure high mobility of chains and styrene blocks fulfill the function of physical crosslinks. In order to achieve elastomeric behavior with a sufficient degree of reversible deformation, it is necessary that each of the structural units forms a continuous phase in the material, which results in a system of two continuous phases from a morphological point of view. Thermoplastic polyurethanes (TPU) also belong to this type of TPE.OrC) The material is composed of a blend of two polymers, most commonly thermoplastic polyolefins (TPO), where dynamic vulcanizates EPDM or EPR are prepared in a PP matrix, while again for the blend to have an elastomeric behavior, a system of two continuous phases must be formed. For the dynamic vulcanization process, the presence of cross-linking additives and / or special compatibilizers is required.In alternatives (B) and (C), the soft phase is usually an amorphous or low crystalline polymer or copolymer with a Tg temperature below the application temperature, usually below 20°C. The hard phase is usually a semi-crystalline or highly crystalline polymer or copolymer with a melting temperature Tm above the application temperature.The above stated methods or solutions for the preparation of highly elastic polymeric materials exhibiting a sufficient degree of elastically reversible deformation have the disadvantage that they require either the synthesis / manufacture of special types of polymers or copolymers, or the polymers need to be chemically modified during the process of manufacturing the final products (cross-linking reactions, vulcanization). Modifications by cross-linking usually lower the ability to undergo biodegradation in the case of biodegradable polymers. Also, cross-linked polymers cannot be mechanically thermoplastically recycled because they lose their thermoplastic properties by cross-linking. In the case of special types of copolymers, it is necessary to prepare (produce) copolymers with various content of components and with various morphologies for a change or adjustment of mechanical properties (modulus, strength, range of elastic deformation, etc.).In connection with the greening of material production, materials made from renewable sources of raw materials and / or biodegradable materials have increasingly become popular in recent years. These efforts are mostly directed to the field of thermoplastic polymers, particularly for packaging applications. These are particularly bio-based thermoplastics of the type PLA, PBS, PBSA, TPS, PHA etc., or synthetic biodegradable materials of the type PCL, PVA, PBAT etc., or bio-based non-biodegradable polymers of the type bioPE, bioPP, etc. However, only thosematerials that are made exclusively from renewable sources of raw materials and are also biodegradable can be considered a fully ecological solution. In the field of elastomers, research and development is particularly oriented on the development of new copolymers based on renewable sources of raw materials, while these are mainly partially bio-based materials, both cross-linkable as well as thermoplastic three -block elastomers. In paper / I / , the authors describe an elastomer based on a cross-linked polymer from renewable sources, while polylactone, obtained by block copolymerization of lactones and cyclic carbonates, was used as the basic polymer, which was subsequently radically cross-linked with peroxide. The polyurethane elastomer is described by the authors of the invention application 121. It is a PU made of biobased diols and bio-based isocyanates with subsequent cross -linking. An equally cross-linkable elastomer produced fully from renewable sources of raw materials is described by the authors of the patent / 3 / , while it is a branched copolymer obtained by reactive blending of PLA and PHA polymers in the presence of peroxides, coagents and cross-linking agents that are of a synthetic nature (e.g. dicumyl peroxide, diallyl phthalates, trimethylolpropane triacrylate and other triacrylates and pentaacrylates, dimethacrylates, etc.).A typical thermoplastic elastomer represented by a triblock copolymer of the type A-B-A derived in part from renewable sources of raw materials is a solution according to the patent / 4 / . The A block is an amorphous polymer chain and the B block is a copolymer of caprolactone and at least one other monomer, such as lactic acid, trimethylcarbonate and glycolic acid, or lactic-co-glycolic acid etc. Another example of TPE, represented by a special bio-based biodegradable copolyester is the copolyester of butanediol, succinic acid and dicarboxylic fatty acid under the name Pripol 1009, whose synthesis and properties are described by the authors of the paper / 5 / . In the paper / 6 / , another type of graft copolymer based on 0- myrcene and PLA is presented, which, according to the authors, shows elastic properties. According to I'll, it is possible to obtain a thermoplastic elastomer film by grafting NR onto P3HB3HH copolymer by using a peroxide initiator. By blending PLA and NR in the presence of a peroxide initiator, a dynamic vulcanizate based on renewable sources of raw materials was prepared according to the paper / 8 / . An equally dynamic vulcanizate was prepared based on PLA and unsaturated biobased polyesters 191.In addition, several patents are published, such as patent / 10 / , where the authors present solutions for increasing the toughness of PLA by blending it with PHA showing a low Tg (below 0°C), while the toughness of PLA or of the entire composition increases, which they evidence by an increase in the relative elongation at break, a decrease in the modulus of elasticity, and an increase in the impact strength. However, these materials do not represent elastomers exhibiting reversible elastic deformation, but these are materials with increased toughness and impact resistance of an otherwise fragile material. It is a dispersion system where in a hard brittle matrix, a polymer is dispersed with a Tg significantly lower than the application temperature of the final products.Similarly, the authors of the patent / ll / state blends of polyhydroxyalkanoates, especially PHB and amorphous PHA (aPHA), while the blend is formed by a dispersion system, where aPHA is dispersed in the hard crystalline matrix of PHB, thereby ensuring increased toughness of the material, particularly impact toughness and ductility of the material, while no elastically reversible deformation of the material is stated. In the description of the invention, the authors clearly state:“

[0010] ”“In general, the present invention describes an environmentally sustainable composition that is useful for the manufacture of polyhydroxyalkanoate -based articles. In particular, the invention pertains to an article of manufacture having a continuous phase and a discrete phase wherein the continuous phase is made up of poly (3 -hydroxybutyrate) homopolymer (PHB) and the discrete phase is an amorphous polyhydroxyalkanoate (PHA).”From this it is clear that they are not considering such a blend that would contain two continuous phases. This is also indicated by the concentration ratios of the components, which in

[0011] are defined by the range for PHB 88%-97.5% and the range for amorphous PHA 2.5-30%, based on which the expert in the given field assumes that it is a dispersed arrangement of a blend with a continuous crystalline and a dispersed amorphous component.It is clear from the above stated that the authors / ll / have the goal of improving the mechanical properties of an otherwise brittle PHB thermoplastic, which they clearly declare:“

[0008] ”:“The present invention addresses a need for improving the durability, the toughness and impact strength of PHA's without compromising its inherent stiffness, strength, ability to biodegrade.”The authors confirm the above stated basic parameters of the solution / ll / also in the detailed description of the invention in

[0018] .Due to the fact that the authors used simple blending of the components to prepare the blends, they apparently did not achieve miscibility of the components, since in

[0019] they write:“The inventors have surprisingly found that multiphase block copolymers are suitable to aid the miscibility of a PHA and PHA, thereby enabling the formation of a blend composition suitable for the production of biodegradable, ocean-degradable and compostable products with appropriate strength and durability”, while in the preceding text they define such block copolymers, particularly based on acrylates, anhydrides, but also other block copolymers.All of the methods known to date for preparing bio-based and / or biodegradable elastomers have at least one of the following disadvantages:Bio-based elastomers are not biodegradable,Biodegradable elastomers are not fully bio-based,It is necessary to cross-link them, which may subsequently reduce the rate of biodegradation,It is necessary to prepare special copolymers by chemical synthesis, particularly copolymers of the type ABA,Reactive blending is necessary to form grafted and / or branched structures,It is necessary to prepare dynamic vulcanizates, which, due to cross-linking reactions, can subsequently reduce the rate of biodegradation.Therefore, it still remains a challenge to find such a class of biodegradable materials from renewable sources of raw materials that behave like TPE and at the same time achieve significant elastically reversible deformation without additional cross-linking reactions or the addition of special compatibilizers, while maintaining full biodegradability even after processing.The essence of the inventionThe above stated disadvantages are solved by the polymer blend according to the invention, which is formed by intensive and thorough blending of at least two polymers and / or copolymers with specific properties, while neither of the base polymers need exhibit typical elastomeric properties. The resulting blend consists thereby of polymers that are 100% bio-based and biodegradable. No further special chemical treatment (grafting, branching, cross -linking, reactive blending, etc.) or other chemical agents are required to achieve the properties of a thermoplastic elastomer. The resulting material has mechanical properties typical for standard thermoplastic elastomers with the ability of reversible elastic deformation in the range of at least 80% for non-oriented products (determined according to methodology M4 described below) and at least 10% for oriented products (determined according to methodology M5 described below).In contrast to the previously known bio-based biodegradable TPE solutions, we were surprised to find that such a biodegradable elastic product can be prepared by intensive and thorough blending of at least two bio-based, biodegradable polymers or copolymers, while the solution according to the invention is based on the method of preparation of a polymer material, which is formed by thorough homogenization of two or more bio-based and at the same time biodegradable polymers or copolymers, preferably polyesters or copolyesters, while the following conditions must be simultaneously fulfilled:1. At least one polymer or copolymer (component A) must be amorphous or with a content of the crystalline phase of max. 2%, or it can be a blend of two or more amorphous polymers or copolymers, while the designation “component A” also applies to this blend, and at the same time the total content of the crystalline phase of such a blend is not higher than 2%.2. At least one polymer or copolymer (component B) must be semi-crystalline or highly crystalline with a content of the crystalline phase of at least 20%, or to it can be a blend of two or more polymers or copolymers, while the designation “component B” further applies to the whole blend and at the same time the condition is fulfilled that the content of the crystalline phase is at least 20%.3. The blending process must be intensive so that during thorough homogenization, the polymer components of the blend are miscible at the molecular level, for example by blending in a co-rotating double screw equipped with at least one kneading zone, while the resulting bio-based biodegradable product (TPE-BBPM) shows reversible elastic deformation of at least 80% (according to the methodology M4 stated below).While preferably4. The stated two polymers or copolymers in the resulting blend are at least in part miscible at the molecular level (thermodynamically miscible), which is shown by a change in the Tg of at least one of them, such that the shift in the Tg of at least one of the polymers is at least 3°C.5. The resulting blend shows the Tg value of the majority amorphous component below the application temperature, usually, but not necessarily, below 20°C.6. The content of the crystalline phase of the blend is in the range from 5 to 35% for products that are not additionally oriented, or the content of the crystalline phase of the blend is from 5 to 40% for products that are subjected to additional orientation, for example by elongation.By intensive blending of component A and component B, as long as the stated conditions 1-3, or 4-6 are fulfilled, thorough homogenization results in a blend characterized by an elastically reversible deformation of at least 80%, determined according to methodology M4 stated below, according to which the test body is prepared using a technology that does not involve additional orientation (for example injection, pressing, extrusion, 3D printing, etc.). In the case where the final product is oriented (for example, films prepared by MDO technology, biaxially oriented films, elongated monofilaments or multifilaments prepared by spinning, etc.), the range of elastically reversible deformation in tension (referred to as RED and determined according to methodology M5) is of at least 10%. The blends prepared according to the invention are further characterized by a wide range of elastic modulus, while the elastic moduli in tension of oriented systems (determined according to methodology M5) range from 1.8 to 160 MPa for the El modulus and from 15 to 2400 MPa for the E2 modulus.Methods and procedures:MlPreparation of blendsThe blends were prepared on a double- screw blending device from Labtech, Thailand. Two screws with a diameter of 16 mm are stored in a case, overlapping each other, rotating in agreement, ratio L / D=40, ending in a head with a circular diameter of 2 mm. During the preparation of the blends, the following temperature profile was set in the direction hopperhead: 80-100-170-4xl90-180-170-160-150°C and the screw speed was set at 200 rpm. In order to achieve sufficient kneading and blending efficiency in order to ensure intensive blending and achieve a thorough blending of polymers at the molecular level, the configuration of the screws in the direction hopper-head was as follows:13D - transport part3.25D - kneading part4D - transport part1.25D - blending part2D - transport part2D - kneading part3D - transport part2.5D - blending part7.5 D - transport part1.5 D - dosing partAll components were dosed into the hopper and the melt of the blend was extruded in the form of monofilament, which was subsequently cooled in a cooling bath with water at a temperature of 20°C and granulated.M2Determination of Tg and crystallinityThe DSC method, Mettler Toledo DSC 1 instrument, in accordance with ISO 11357, was used to determine Tg and crystallinity. A sample of 10-15 mg weight was weighed and sealed in analuminum dish. The dish was placed in the autosampler of the instrument. The measurement program was as follows:Isotherm 3 minutes at -70°C,1stheating from -70°C to 200°C at a rate of lOK / min,Isotherm 3 minutes at 200°C,Cooling from 200°C at a rate of lOK / min,Isotherm 3 minutes at -70°C,2ndheating from -70°C to 200°C at a rate of lOK / min.From the first heating, the melting enthalpy of the crystalline fractions was evaluated, from the second heating, the Tg value was evaluated using the evaluation program STAR 16.40, while the melting enthalpy was evaluated as an integral under the endothermic melting peak, and the temperature Tg was evaluated as the inflection point of the Tg thermal transition. If only the P3HB polymer segments were used as the crystallizing component in the prepared blends, a value of 146 J / g was used as the melting enthalpy of 100% crystallite, a value of 136 J / g was used as the melting enthalpy of 100% crystallite for PCL, and a value of 114 J / g was used as the melting enthalpy of 100% crystallite for PBAT for the calculation of the crystallinity of the blend. The crystallinity was subsequently calculated according to the formula V 1where%K - crystallinity (percentage of crystalline fractions)AHm- melting enthalpy J / g (as an integral - normalized)AHo - melting enthalpy of 100% crystallite J / gGraphically, the determination of Tg and AHm from the DSC record is shown in Fig. 1.In order to determine the accuracy of the measurement of individual parameters, the standard deviation of the arithmetic mean of 10 repeated measurements was determined, while for individual parameters it acquired the following values:Parameter the value of the standard deviation of the arithmetic meanTg + / - 0.30 °CCrystallinity + / - 0.41%M3Preparation of bodies for measuring elastically reversible deformationThe injection technology was used to prepare bodies according to ISO 527, type 1BA, which were used for the measurement of elastically reversible deformation. The bodies were produced on BOY 60E device with the following parameters of the injection process:- Injection volume 18cm3,- Injection speed 10cm3 / s,- Pressure 600bar,- Holding pressure 1200bar,- Holding pressure time 10s,- Cooling time 15s,- Mold temperature 30°C,- Temperature profile in the direction hopper- nozzle: 160-170-175-170-170°C.M4Determination of elastically reversible deformationA proprietary methodology has been developed for the measurement of elastically reversible deformation. The molded body according to the procedure M3 in the shape according to the ISO 527 standard, type 1BA, was attached in the wider part to the holder in a vertical position so that it formed an angle of 90° with the horizontal support. Subsequently, the body was bent by 90°, i.e. into a horizontal position for 15 seconds. After 15 seconds, the body was released, and after another 15 seconds, the elastically reversible deformation was read on the scale as a percentage of the return of the body to the starting position. Schematically, the test is shown in Fig. 2.M5Determination of the range of elastically reversible deformation (RED) in tension and El and E2 moduliThe Range of Elastically reversible Deformation (RED) in tension and the tensile moduli El and E2 are defined as shown in Fig. 3. According to procedure M6, monofilaments were prepared, which were subsequently elongated according to procedure M7. The tensile curve of the prepared and elongated monofilaments was measured on a Zwick Roell device at a jaw displacement speed of 100 mm / min. The first part of the curve corresponds to the elastically reversible deformation, the second part of the curve corresponds to the increase in stress beyond the limit of the elastically reversible deformation during tensile stress up to rupture. The El modulus represents the amount of stress required for the elastic deformation of the test body and is determined as the direction of the linear part of the tensile curve in the range of elastically reversible deformation. The modulus E2 represents the amount of stress required to deform the body beyond the limit of elastically reversible deformation to rupture and is determined as the direction of the straight line E2. The range of elastically reversible deformation (RED) is then determined as a coordinate on the axis of relative elongation, belonging to the intersection of the two straight lines for determining El and E2. The method of determination is evident from Fig. 3.M6Procedure for the preparation of monofilamentsFrom the prepared granulate of individual blends, the production of monofilaments was carried out on a Brabender single-screw extruder with screw parameters D=19mm, L / D=25 with a compression ratio of 1:3. During the preparation of monofilaments with a diameter of 1 mm, the following temperature profile was set in the direction hopper-head: 190-180-170-160°C.Through a nozzle with a circular diameter of 1.8mm, the polymer melt was extruded into a tempering bath with a water temperature of 30°C. After exiting the fdament from the water bath, the filament was freed from surface moisture by passing the filament through a slot connected to a vacuum, and subsequently, the filament prepared in this way was oriented by elongation.M7Procedure for lengthening monofilaments to the maximum elongation ratioThe prepared filaments were oriented by elongation to the maximum possible elongation ratio on the KMS-PT elongation device, which is equipped with a system of three feeding rollers and a system of three withdrawal rollers. The elongation ratio was set by different speeds of the feeding and take-up rollers. Elongation between both sets of cylinders took place in a water bath on a track of Im at a temperature of 80°C.Description of the solution according to the inventionThe principle of the solution according to the invention uses the surprising finding that the same effect of elastically reversible deformation as in the formation of cross-links during polymer cross-linking, or as in special types of copolymers, particularly of the type ABA, or as in the compatibilization of two polymers or copolymers on mesophase (dynamic vulcanizates), can be achieved in blends of at least two bio-based biodegradable polymers or copolymers, none of which needs to be an elastomer, in such a way of preparation of a blend, in which, as a result of intensive blending, thorough homogenization of at least two polymers or copolymers takes place, of which:At least one is an amorphous polymer, or a polymer with a content of the crystalline phase of max. 2%, or it can be a blend of two or more amorphous polymers or copolymers, while the total content of the crystalline phase of such a blend is not higher than 2% - component A,At least one is a semi-crystalline or highly crystalline polymer with a content of the crystalline phase of at least 20%, or to it can be a blend of two or more polymers or copolymers, while the content of the crystalline phase is at least 20% - component B,WhileThe resulting homogenized blend shows an elastically reversible deformation of at least 80%, determined according to the stated methodology M4,When in additionThe stated at least two polymers or copolymers in the resulting blend are at least in part miscible at the molecular level (thermodynamically miscible), which is shown by a change in the Tg of at least one of them, such that the shift in the Tg of at least one of them is at least 3°C,The resulting blend shows a Tg value of the majority amorphous component below the expected application temperature of the polymer product, usually, but not necessarily below 20°C.The content of the crystalline phase of the blend is in the range from 5 to 35% for products that are not additionally oriented, or the content of the crystalline phase of the blend is from 5 to 40% for products that are additionally oriented.The blending process must be intensive so that during thorough homogenization the polymer components of the blend are miscible at the molecular level, for example by blending in a co-rotating double-screw equipped with at least one kneading zone.TPE-BBPM is formed by the above stated method of preparation, which will allow at least partial miscibility at the molecular level (thermodynamic miscibility) of at least two polymers, while at least one is from the group of polymers composing component A and at least one is from the group of polymers composing component B, while at least one of the components of the blend must be able to form a continuous hard phase at the application temperature (for example, a semi-crystalline polymer with a Tm above the application temperature) and at least one of the components must be able to form a continuous soft phase at the application temperature with a Tg below the application temperature.The principle of preparation of such blends consists in the thorough blending of the components of the blend to form such a morphology of the blend, where the continuous hard phase is formed by the crystalline component of the blend (semi-crystalline or highly crystalline polymer), and the continuous soft phase is formed by segments of at least one amorphous polymer with a Tg below the application temperature. If the components of the blend were not at least in part miscible at the molecular level, it would be possible to form either a dispersion system with a continuous hard phase and a dispersed soft phase, providing a tough material such as in the patent / l l / , or a plastically deformable material without elastically reversible deformation would be formed, if a dispersion system with a continuous soft phase and a dispersed hard phase was formed and a typical thermoplastic elastomer material would not be obtained it that way. However, if there is at least a partial blending of the amorphous phases at the molecular level (due to the thermodynamic miscibility of polymers), which is ensured by intensive thorough blending of the blend, two continuous phases are formed (a continuous soft phase and a continuous hard phase) and the plastic flow of the resulting material at the application temperature is not possible and the deformation by the action of external forces has an elastic character to the extent which is determined by the ratio of the concentrations of continuous hard and continuous soft phases in the blend and their morphological arrangement. For illustration, in Fig. 4 the structure of the resulting blend of soft (amorphous) and hard (semicrystalline) polymer without the miscibility of amorphous phases at the molecular level of both components is shown, and in Fig. 5 with mutual miscibility of amorphous phases at the molecular level.In Fig. 4, the phase interface is shown by the blue line. With mechanical stress above the Tg of the amorphous soft component, plastic flow of the material will occur without elastically reversible deformation. However, if the amorphous phases of both polymers are blended at the molecular level and thus form a common amorphous soft phase with one Tg (schematically in Fig. 5) and at the same time the system will contain enough of a hard component, for example crystallites, which will also form a continuous phase by connecting through a common amorphous soft phase, then above the Tg of the amorphous soft phase only deformation will be possible in the range of straightening of segments of the amorphous soft phase between individual hard phase domains, for example crystallites. After the removal of the external force, the straightened amorphous soft chains will return to their initial position, which will be macroscopically shown by a reversible elastic deformation.Miscibility at the molecular level of the amorphous phases of blended polymers can be demonstrated by determining the Tg value using DSC. According to generally known knowledge, if two polymers are thermodynamically miscible, i.e. miscible at the molecular level, they have one Tg value in common, which lies between the two Tg values of the individual components. If there is no blending at the molecular level, the blend shows two Tg values identical to the Tg of the components, which do not change after the blend is formed. To describe the dependence of the Tg of a miscible blend on the composition of the blend (proportion of both polymers), the literature presents several mathematical models, as for example the Fox equation, the Gordon-Taylor equation, the Brekner-Schneider-Cantow relationship and others / 12,13 / , which clearly document the shift in the Tg of the common blended amorphous phase of the two polymers compared to the Tg of the pure components, while the Tg value of the blend lies usually between the two Tg values of the blended polymers.The invention deals with thermoplastic elastomers (TPE) based on 100% bio-based and 100% biodegradable polymers (TPE-BBPM), which can subsequently be modified by further additives, including other polymer components.TPE-BBPM is prepared by intensive and thorough blending of at least two bio-based, biodegradable polymers or copolymers, or a polymer and a copolymer, of which at least one is amorphous or only slightly crystalline with a Tg below the application temperature, while the content of the crystalline phase does not exceed 2% - component A and the second is semicrystalline, while the content of the crystalline phase is at least 20% - component B. At least two polymers or copolymers, of which at least one is semi-crystalline with a content of the crystalline phase of at least 20%, and at least one is amorphous or low-crystalline with a content of the crystalline phase of max. 2% with a Tg below the application temperature, must also show at least partial miscibility at the molecular level, which is shown by a shift in the Tg of at least one of them by at least 3°C compared to the Tg value of the amorphous phase of the pure component, and at the same time the content of the crystalline phase of the whole blend must be in the range from 5 to 35%, if it is final products produced without orientation, or from 5 to 40%, if it is final products produced with orientation. The blending of the polymers must be so intensive that it enables a thorough blending of the amorphous components of the blend, while usually it is an intensive dispersive blending, for example in co-rotating double-screws equipped with at least one kneading zone.The polymers or copolymers of component A and of component B are preferably polymers or copolymers from the group of polyesters, preferably polymers or copolymers from the group of poly hydroxy alkanoates and / or polylactides.The blends prepared in this way then show, depending on the content of crystalline components, an elastically reversible deformation in a relatively wide range, which is shown in the case of mechanical stress of non-oriented test bodies in bending by an elastically reversible deformation at the level of at least 80%, tested according to procedure M4, in the case of oriented test bodies is the range of elastic deformation (RED parameter according to procedure M5) in tension of at least 10% relative elongation. Mechanical properties, such as tensile modulus in the elastic area of tensile deformation (El according to the methodology M5), tensile modulus in the area of the subsequent inelastic deformation (E2 according to the methodology M5), tensile strength at break, relative elongation at break, modulus of elasticity in bending, etc., can be modified by setting the ratio of the concentrations of the amorphous and crystalline phase in the range of the content of the crystalline phase from 5 to 35%, respectively 5 to 40%, while a lower content ofthe crystalline phase will provide lower moduli and a higher rate of elastically reversible deformation (RED) and conversely, a higher content of the crystalline phase will provide higher moduli El, E2, flexural modulus, higher breaking strength and a lower range of elastically reversible deformation RED and a lower relative elongation at break.The mechanical properties of TPE-BBPM prepared in this way can be further modified by addition of another bio-based and biodegradable polymer, which does not have to form a continuous phase and does not have to be at least partially miscible at the molecular level with at least one polymer of the blend, while the condition of the range of the total content of the crystalline proportions of the basic blend between 5 and 35%, or between 5 and 40% must be ensured, while at the same time there are changes in the mechanical properties of the blend.The mechanical properties may be further modified by addition of suitable plasticizers, such as for example citric acid esters.The mechanical properties can be further modified also by further polymers, that do not have to be bio-based, but are biodegradable, as for example PCL, PBAT, PBS, PBSA, etc.The properties of elastomeric blends according to the present invention can be further modified by further additives, such as inorganic and organic fillers, pigments and dyes, slip agents, nucleating agents, processing additives, antidegradants, branching agents, chain extenders, plasticizers, antistatic agents, blowing agents and others.Overview of figures on drawingsFig. 1. Determination of AHm(left) and Tg (right) from DSC recordingFig. 2 Scheme of the test for the determination of elastically reversible deformation. A - starting position, B - body bent by 90°, C - body after releaseFig. 3. Tensile curve and method of determination of RED, El and E2 parametersFig. 4. Scheme of the morphology of amorphous (black) and semi-crystalline (red) polymer without miscibility of amorphous phases at the molecular level. Blue lines show the phase interface.Fig. 5. Scheme of the morphology of amorphous (black) and semi-crystalline (red) polymer whose amorphous components are miscible at the molecular levelExamples of embodimentsUsed polymers and their characteristicsUsed plasticizersExample 1According to procedure Ml, granulates of blends with the composition listed in Table 1 were prepared and values of crystallinity and Tg were determined according to procedure M2.Table 1. Composition, crystallinity and Tg temperatures of blends B1-B10From all blends, bodies were prepared by injection according to procedure M3 for measuring elastically reversible deformation according to procedure M4. The results are stated in Table 2.Table 2. Elastically reversible deformation for samples from Table 1, measured at 23 °CFrom all blends according to Table 1, according to the procedure M6, monofilaments were prepared, which were subsequently oriented by elongation to the maximum elongation ratio according to procedure M7. Subsequently, El, E2 and RED parameters were determined according to procedure M5. The results are stated in Table 3.Table 3. Crystallinity and elastic properties of elongated monofilaments, measured at 23 °CN / A - the filaments could not be elongated to the final elastic productExample 2According to procedure Ml, granulates of blends with the composition listed in Table 4 were prepared and values of crystallinity and Tg were determined according to procedure M2.Table 4. Composition, crystallinity and Tg temperatures of blends B11-B18From all blends, bodies were prepared by injection according to procedure M3 for measuring elastically reversible deformation according to procedure M4. The results are stated in Table 5.Table 5. Crystallinity and elastically reversible deformation for samples from Table 4, measured at 23 °CFrom all blends according to Table 4, according to the procedure M6, monofilaments were prepared, which were subsequently oriented by elongation to the maximum elongation ratio according to procedure M7. Subsequently, El, E2 and RED parameters were determined according to procedure M5. The results are stated in Table 6.Table 6. Crystallinity and elastic properties of elongated monofilaments from Table 4, measured at 23 °CN / A - the filaments could not be elongated to the final elastic productExample 3According to procedure Ml, granulates of blends with the composition listed in Table 7 were prepared and values of crystallinity and Tg were determined according to procedure M2.Table 7. Composition, crystallinity and Tg temperatures of blends B19-B29elastically reversible deformation according to procedure M4. The results are stated in Table 8.Table 8. Crystallinity and elastically reversible deformation for samples from Table 7, measured at 23 °CFrom all blends according to Table 7, according to the procedure M6, monofilaments were prepared, which were subsequently oriented by elongation to the maximum elongation ratio according to procedure M7. Subsequently, El, E2 and RED parameters were determined according to procedure M5. The results are stated in Table 9.Table 9. Crystallinity and elastic properties of elongated monofilaments from Table 7, measured at 23 °CExample 4According to procedure Ml, granulates of blends with the composition listed in Table 7 were prepared and values of crystallinity and Tg were determined according to procedure M2.Table 10. Composition, crystallinity and Tg temperatures of blends B30-B47From all blends according to Table 10, according to the procedure M6, monofilaments were prepared, which were subsequently oriented by elongation to the maximum elongation ratio according to procedure M7. Subsequently, El, E2 and RED parameters were determined according to procedure M5. The results are stated in Table 11.Table 11. Crystallinity and elastic properties of elongated monofilaments from Table 10, measured at 23 °CExample 5According to procedure Ml, a granulate of the blend with the composition stated in the Table 12 was prepared and values of crystallinity and Tg were determined according to procedure M2.Table 12. Composition, crystallinity and Tg temperatures of blend B48Subsequently, PBAT and PCL polymers were added to blend B49 as property modifiers - the composition of blends is stated in Table 13.Table 13. Composition of blends B49 to B54From a 1 blends according to Table 12 a 13, according to the procedure M6, monofilaments were prepared, which were subsequently oriented by elongation to the maximum elongationratio according to procedure M7. Subsequently, El, E2 and RED parameters were determined according to procedure M5. The results are stated in Table 14.Table 14. Elastic properties of elongated monofilaments from Table 13, measured at 23°CExample 6According to procedure Ml, granulates of blends with the composition listed in Table 15 were prepared and values of crystallinity and Tg were determined according to procedure M2.Table 15. Composition, crystallinity and Tg temperatures of blends B55-B61From all blends according to Table 15, according to the procedure M6, monofilaments were prepared, which were subsequently oriented by elongation to the maximum elongation ratio according to procedure M7. At a temperature of 23°C, the blends did not behave elastically, as the Tg of the amorphous part (PLA) is 57.9°C. Elastic properties were measured at temperature 80°C. At this temperature, the El, E2 and RED parameters were determined according to procedure M5. The results are stated in Table 16.Table 16. Elastic properties of elongated monofilaments from Table 15, measured at 80°CIndustrial applicabilityThe invention deals with thermoplastic elastomers (TPE) based on 100% bio-based and 100% biodegradable polymers (TPE-BBPM), which can subsequently be modified by further additives, including other polymer components. Such thermoplastic elastomers (TPE) show an elastically recoverable deformation of at least 80%, which predisposes them to use in many areas of industry where it is necessary to use highly elastic polymer materials.Cited literature1. Brutman, J.P. et al. Method for making renewable and chemically recyclable crosslinked polyester elastomer, US 10 808 084 B22. Croom, K.A., Bio-based and biodegradable elastomer for cosmetic and personal care, US 2021 / 0059924 Al3. Krishnaswamy, R.K. et al., Biobased rubber modified biodegradable polymer blends, US 10 113 060 B24. Venkatraman et al., Biodegradable thermoplastic elastomers, 2014, US 8 716 410 B25. Quattrosoldi, S. et al., Fully biobased, elastomeric and compostable random copolyesters of poly (butylene succinate) containing Pripol 1009 moieties: structureproperty relationship, Polymer degradation and stability 178, 2020, DOI: https : / / doi.org / 10.1016 / j .polymdegradstab.2020.1091896. Cheng, Z. et al., Fully biobased thermoplastic elastomers: Synthesis of highly branched linear comb poly (b-myrcene) -graft-poly (L-lactide) copolymers with tunable mechanical properties, Polymer 138, 2018, DOI: https : / / doi.org / 10.1016 / j .polymer.2018.01.0457. Asmaa Z., A. et al., Sustainable grafting of poly(3-hydroxybutyrate-co-3- hydroxyhexanoate) and natural rubber into a new thermoplastic elastomer film, polymer, 289, 2023, DOI: https: / / doi.Org / 10.1016 / j.polymer.2023.1264768. Wan-Jie, S. et al., Tailoring toughness of fully biobased poly(lactic acid) / natural rubber blends through dynamic vulcanization, Polymer testing, 65, 2018, DOI: https: / / doi.Org / 10.1016 / j.polymertesting.2017.l l.0309. De-Fu, L. et al., Dual effect of dynamic vulcanization of biobased unsaturated polyester: Simultaneously enhance the toughness and fire safety of Poly(lactic acid), Composites Part B, 175, 2019, DOI: https: / / doi.org / 10.1016 / j.compositesb.2019.10706910. Krishnaswamy, R.K. Toughening polylactic acid with polyhydroxyalcanoates, 2013, US 2013 / 0065046 Al11. Leon Jeffery, Wollack Scott, Multiphased polyhydroxyalcanoate-based blends and articles made therefrom, 2023, WO 2023 / 154926 A212. loannis M. Kalogeras, Witold, B. Glass transition temperatures in binary polymer blends, Journal of Polymer Science: Part B: Polymer Physics, Vol. 47, 80-95 (2009), DOI: 10.1002 / polb.2161613. Tan, I.K.P. et al. Eco-friendly plasticizer for poly(vinylchloride), 2014, WO 2014 / 014337

Claims

Claims1. Thermoplastic biodegradable polymer material from renewable sources (TPE-BBPM) characterized in that it shows elastically reversible deformation of at least 80%, which is determined according to method M4 stated in the description of the invention, while the material contains at least one component A and at least one component B ; while the component A is a biodegradable polymer from renewable sources, or a copolymer, which is amorphous or low-crystalline, while the total content of the crystalline phase of the component A is a maximum of 2 Wt % ; and the component B is a biodegradable polymer from renewable sources or a copolymer, which is semi-crystalline, while the total content of the crystalline phase of the component B is at least 20 Wt %.

2. Thermoplastic biodegradable polymer material from renewable sources according to claim 1 characterized in that the total content of the crystalline phase in the resulting blend determined according to the methodology M2 stated in the description of the invention is in the range from 5 to 35 Wt %.

3. Thermoplastic biodegradable polymer material from renewable sources according to claim 1-2 characterized in that the amorphous phases of at least two polymers or copolymers in the blend are at least in part thermodynamically miscible at the molecular level so that at least one of the polymers deviates its Tg value by at least 3°C from its original value.

4. Thermoplastic biodegradable polymer material from renewable sources according to claims 1-3 characterized in that components A and B are from the group of polyesters, preferably from the group of polyhydroxy alkanoates and / or polylactides.

5. Thermoplastic biodegradable polymer material from renewable sources according to claim 1-4 characterized in that it contains additional additives and property modifiers.

6. Thermoplastic biodegradable polymer material from renewable sources according to claim 5 characterized in that additives and modifiers are selected from the group: plasticizers, biodegradable polymers, inorganic fillers, organic fillers, pigments, dyes, slip agents, antiblocking agents, nucleating agents, processing additives, antidegradants, branching agents, chain extenders, antistatic agents, blowing agents.

7. Oriented elongated material TPE-BBPM according to claims 1-6 characterized in that the total content of the crystalline phase in the resulting blend determined according to the methodology M2 stated in the description of the invention is in the range from 5 to 40 Wt %, and the elongated material reaches the RED parameter according to methodology M5 stated in the description of the invention of at least 10%.

8. Oriented elongated material TPE-BBPM according to claim 7 characterized in that components A and B are from the group of polyesters, preferably from the group of polyhydroxy alkanoates and / or polylactides.Thermoplastic biodegradable polymer material from renewable sources according to claims 1-8 characterized in that at least one Tg value in the polymer product is below the application temperature of the product.

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