Rubber mixture for recyclable and degradable rubbers

Abstract

The invention relates to a rubber mixture containing a polyester having at least one saturated and unsaturated monomer that can be processed to give a rubberlike vulcanizate which is degradable by virtue of the ester bonds present, and to a production process for this rubber mixture. The invention further relates to a recycling process comprising a solvolysis step and removal and purification steps, and repolymerization of the monomers and / or oligomers obtained.

Description

Rubber compound for recyclable and degradable rubbers Technical area

[0001] The present invention relates to a vulcanizable or crosslinkable rubber mixture for recyclable and degradable polyester-based elastomers and to its use and a process for its recycling. State of the art

[0002] Vulcanizates, or rubbers, are among the polymer materials with the highest production volumes. This is due to their outstanding mechanical and thermal properties, making them ideal for use in car tires, for example. The most commonly used rubbers include natural rubber, styrene-butadiene copolymers (SBR), polybutadiene (BR), and polyisoprene. These mostly amorphous polymers can be crosslinked or vulcanized with sulfur, peroxides, and azo initiators, for example, to create an elastic material.

[0003] Currently, only a small proportion of the rubber produced is recycled, and it also degrades very slowly in the environment. This poses an environmental problem due to the high production volumes, which amount to millions of tons, and also means that immense resources cannot be further utilized.

[0004] A closed material cycle is desirable. It assigns value to waste, which reduces the release of potentially harmful substances into the environment. Reusing raw materials also prevents the use of limited fossil fuels.

[0005] Mechanical recycling is successfully used for many polymers, such as HDPE and PET. Since vulcanizates are thermosets, meaning they cannot be melted, they cannot be recycled this way.

[0006] Chemical recycling of polymers describes the breakdown of the chains into their basic components, or monomers, from which materials with identical properties can then be produced again. For polymers with predetermined breaking points, such as ester groups in PET, chemical recycling is carried out industrially using solvolysis processes.

[0007] Pyrolysis offers one option for recycling polymers without predetermined breaking points. Using high energy input and catalysts, the polymer chains are broken, and the solid polymer is converted into liquid and / or gaseous molecules. This creates a random product mixture that generally cannot be used directly for polymerization into materials with the same properties. The products are often subsequently thermally recycled. Using suitable catalysis, specific monomers can be produced. These catalysts are typically very sensitive to contaminants and / or foreign atoms such as sulfur. Pyrolysis currently does not allow for a closed material cycle for rubber.

[0008] The practice of recycling vulcanizates, illustrated here using car tires as an example, can best be described as downcycling, as it results in lower-value products. Shredded car tires are primarily added to asphalt or used as fillers. Devulcanization is intended to selectively break the sulfur crosslinks in rubber. Devulcanized rubbers can be added proportionally to newly produced rubber during rubber production, although this leads to a deterioration of the properties. Furthermore, products such as tartan tracks or underlays can also be made from rubber.

[0009] There are several concepts for producing recyclable elastomers. These include thermoplastic elastomers (TPEs) and vitrimers. TPEs They are manufactured and used industrially and are mechanically recyclable, but they have several disadvantages compared to vulcanizates. They are generally less cost-effective to produce, have lower thermal and mechanical stability, exhibit creep behavior over extended use, and generally cannot be loaded with fillers such as carbon black, which prevents their use in car tires.

[0010] Recyclable polyester networks with elastic properties can also be produced through the polycondensation of di- and multifunctional monomers. The networks are created during the time-consuming synthesis process and not, as with rubber, during the comparatively rapid vulcanization process. Since cross-linked polymers are insoluble and non-meltable, the polycondensation would have to take place in the shape of the component to be manufactured. Such a process is not scalable, very costly and time-consuming, and thus prohibitive for industrial use.

[0011] Tire wear releases rubber microplastics into the environment. Microplastics are often ingested by organisms. Humans can ingest microplastics through the air we breathe or through the food chain. It is suspected that the ingestion of microplastics can lead to numerous health problems, for example, because they serve as a vector for toxic, hydrophobic substances into the human body. Biodegradable elastomers, and rubbers in particular, offer a way to counteract the accumulation of microplastics and the resulting harm to humans and the environment. Description of the invention

[0012] The task was therefore to provide a material which has the properties of the vulcanizates known in the state of the art and can be processed in an analogous manner.

[0013] In addition, an economical process is needed with which valuable oligomeric and / or monomeric components of the starting material can be recovered from the vulcanized material.

[0014] Ideally, the chemical composition of the polymer according to the invention should be designed in such a way that the microplastics that inevitably arise as abrasion can be degraded in the environment.

[0015] One or more of the above objects has been achieved by the present invention of a vulcanizable rubber mixture for producing a rubber-like vulcanizate.

[0016] The polymer contained in the rubber compound is described by the following formula: [-(O=C)-A-(C=O)-OBO-] n (I) , where A has the molecular formula C cHd, where the index c is an integer from the range 2 - 200, for example from 2 - 20, and the index d is an integer from the range 2 - 400, for example from 2 - 40, B is the molecular formula C e Hf, where the index e is an integer from the range 2 - 200, for example from 2 - 20, and the index f is an integer from the range 2 - 400, for example from 2 - 40, where at least one of the components A or B does not contain an isolated or conjugated double bond and at least one of the components A or B contains an isolated or conjugated double bond and the index n is an integer from the range 5 - 50,000. A and B can be freely selected in each repeat unit according to defined conditions.

[0017] A and B can be different, meaning they are not identical. However, A and B can also have an identical molecular formula but a different structure or arrangement.

[0018] In one embodiment, A and / or B of the general formula (I) is a repeating unit of the general formula (II) given below.

[0019] In one embodiment, A and / or B of general formula (i) is a repeating unit of general formula (III) below.

[0020] Aromatic systems are not understood here as conjugated double bonds.

[0021] The polymer composed of the [-(O=C)-A-(C=O)-OBO-] repeat units is a polyester of the type -[-AA-BB-]-. AA and BB denote the same functionality on the monomers. Polyesters of the type -[-AA-BB-]- are obtained via a step-growth polycondensation of an AA monomer, such as a diacid (HO-(O=C)-A-(C=O)-OH) or diacid ester (RO-(O=C)-A-(C=O)-OR), with a BB monomer, such as a diol (HO-B-OH).

[0022] Due to the ester groups it contains, the material is chemically recyclable or biodegradable via solvolysis.

[0023] The polyester described in formula (I) consists of at least two different monomers, AA and BB, which are either diols, diacids, or diesters. At least one of the monomers has an isolated or conjugated double bond, while at least one monomer does not contain an isolated or conjugated double bond. Thus, in the synthesized polymer, one type of monomer (with an isolated or conjugated double bond) is crosslinked at the site of the double bonds during vulcanization, while the other type of monomer (without an isolated or conjugated double bond) does not undergo any chemical reaction during vulcanization.

[0024] Examples of saturated monomers are hydrogenated dimer fatty acids, ethylene glycol, dibutyl malonate and saturated glycol modified polyhydroxy fatty acids.

[0025] Examples of unsaturated monomers are hexenedioic acid, itaconic acid, maleic acid, fumaric acid and unsaturated glycol-modified polyhydroxy fatty acids.

[0026] The unsaturated monomer should preferably consist of a C4-C6 unit to enable the highest possible recycling rate. The unsaturated oligomers of polyhydroxy fatty acids are characterized by C4-C9 monomer units that carry a variable proportion of terminal double bonds in the side chain.

[0027] Ideally, the saturated monomers should be such that they result in a hydrophobic, amorphous polymer, yet can still be separated from other monomers using simple methods. Furthermore, the monomers should be inexpensive.

[0028] The invention also includes bio-based substances such as the monomers dimer fatty acids, ethylene glycol, itaconic acid and especially polyhydroxy fatty acids, also known as polyhydroxyalkanoates (PHA).

[0029] The present invention relates in one variant to the use and modification of unsaturated medium-chain (mcl) PHAs having C6 to C14 carbon side chains per monomer unit or long-chain (Icl) PHAs having monomer units with more than 15 carbon atoms.

[0030] Unsaturated mcl PHAs and / or Icl PHAs can be produced, for example, by fermentation of native or recombinant bacterial strains such as Pseudomonas putida KTQQ20 and Pseudomonas entomophila LAC23. These strains are capable of producing PHAs with functional groups in their side chains when fed with fatty acids containing functional groups such as double or triple bonds, epoxide groups, carbonyl groups, cyano, phenyl, and halogen groups. [0031 JSpeziel I mcl PHA and Icl PHA with portions of isolated internal or terminal double bonds in the side chains are of interest for the present polymer according to the invention.

[0032] Due to their high side chain density, Mcl and Icl PHA exhibit low crystallinity and can exist in both semicrystalline and amorphous form. These properties make them particularly suitable as oligomeric and polymeric building blocks for the preparation of block copolymers of the polymer of the invention or as blend and crosslinking partners. The number-average molecular weight of the modified hydroxy-terminated unsaturated polyhydroxyalkanoates is between 2,000 and 200,000 g / mol, preferably between 2,000 and 20,000 g / mol.

[0033] Hydroxylation and end-group functionalization, for example, through acid-catalyzed depolymerization with ethylene glycol, play a crucial role in the production of these oligomeric building blocks. Hydroxylation modifies the functional groups of the PHAs. Depolymerization enables the controlled decomposition of the PHAs into defined hydroxy-terminated oligomers, which can be used as building blocks for block copolymers and AA / BB polycondensations.

[0034] The hydroxy-terminated mcl PHA and / or Icl PHA used in the polycondensation is described by the following formula: HO-GO-[-(O=C)-AO-(C=O)-BO-] n -H (II)

[0035] Since the polymer is produced via conventional polycondensation, important polymer parameters such as double bond density, ester bond density and the incorporation of aromatic monomers can be easily adjusted.

[0036] The polycondensation is catalyzed at temperatures between 100 - 350 °C, preferably between 120 and 180 °C.

[0037] Mcl PHA increases the ester bond density of the polymer and thus has a significant effect on the material properties of the polymer, since the ester bond density influences, among other things, the polarity, the degradability of the polymer, as well as the miscibility of the polymer with other polymers and elastomers.

[0038] At the same time, the ester bond density facilitates the degradability of the material, which is why variants of the polymer according to the invention with PHA components are more susceptible to hydrolytic and enzymatic degradation in natural environments.

[0039] In an advantageous embodiment of this invention, a mcl PHA and / or Icl PHA of formula (III) is used in the rubber mixture as a blend partner, and / or a hydroxy-terminated mcl PHA and / or Icl PHA of formula (II) as an oligomeric building block for a polycondensation to produce the rubber material: HO-GO-[-(O=C)-AO-(C=O)-BO-] n -H (ID HO-[-(O=C)-AO-(C=O)-BO-]nH (III), where A has the molecular formula C c Hd, where the index c is an integer from the range 2 - 200, for example from 2 - 20, and the index d is an integer from the range 2 - 400, for example from 2 - 40, B is the molecular formula C eHf, where the index e is an integer from the range 2 - 200, for example from 2 - 20, and the index f is an integer from the range 2 - 400, for example from 2 - 40, where at least one of the components A or B does not contain an isolated or conjugated double bond and at least one of the components A or B contains an isolated or conjugated double bond and the index n is an integer from the range 5 - 50,000, where G has the empirical formula C g Hh, where the index is an integer in the range 2-50, where the index h is an integer in the range 4-100. A and B can be freely selected in each repeating unit according to defined conditions. [0040A and B can be different, i.e., not identical. However, A and B can also have an identical molecular formula but a different structure or arrangement.

[0041] An example of a possible repeating unit G is shown in Figure 5. This repeating unit allows the introduction of additional diols into the polymer structure.

[0042] The polymer of general formula (II) can be used as component AA or BB for the preparation of a polymer of general formula (I).

[0043] The polymer of general formula (II) can be obtained, for example, from a depolymerization reaction of an unsaturated mcl PHA polymer of general formula (II).

[0044] A possible example of a hydroxy-terminated, glycol-modified, unsaturated mcl PHA according to general formula (II) is shown in Figure 3.

[0045] The polymer of general formula (III) can be used as a blend and / or crosslinking partner for a polymer of general formula (I).

[0046] A possible example of a polymer of general formula (III) is shown in Figure 4.

[0047] The polymer of the invention preferably has a crystallinity of less than 20%; ideally, the polymer is completely amorphous. This can be achieved by using branched monomers, such as dimer fatty acids and mcl PHA and / or 1d PHA.

[0048] In one embodiment, the number average molecular weight of the polymer is between 5,000 and 5,000,000 g / mol, for example between 50,000 and 200,000 g / mol.

[0049] In one embodiment, the glass transition point of the polymer is between -150 and 50 °C, for example between -150 and -40 °C.

[0050] The polymer produced in this way can be vulcanized using conventional techniques, such as conventional vulcanization with sulfur and other additives, and produces an elastic, rubber-like material. It is thus compatible with existing manufacturing processes and could be used, for example, in the production of car tires.

[0051] Other additives that can be added include, for example, oxidation stabilizers, foam stabilizers, plasticizers, compatibilizers, UV stabilizers, dyes, inorganic fillers or biofillers, such as olive kernel flour or walnut shell flour, and / or rice husk ash (RHA).

[0052] The unsaturated polyester produced in this way can also be crosslinked with other common crosslinking systems based on organic peroxides, for example dicumyl peroxide or dilauryl peroxide, but also azo initiators such as AIBN, optionally in combination with other additives.

[0053] Vulcalization or cross-linking in the presence of a chemical foaming agent, such as azodicarbonamide, sodium bicarbonate, or by means of a physical foaming process, allows the production of foamed elastic products, such as mattresses, soles for the sports shoe industry or water sports articles.

[0054] The crosslinking of the polymer according to the invention can also be achieved through the use of photoinitiators. Photoinitiators are substances that generate radicals upon exposure to UV or visible light, which in turn initiate the polymerization and crosslinking of the polymer chains. Common photoinitiators include benzoin ethers, benzil ketals, and acylphosphine oxides. These can be used for potential applications such as the production of UV-curing adhesives for the electronics industry, dental and medical technology, and for special packaging that are both reversible and biodegradable.

[0055] Furthermore, photoinitiated crosslinking can also be used to produce coatings and paints with high abrasion and chemical resistance. These properties are particularly important in the automotive industry, for furniture coatings, and the construction industry.

[0056] Finally, photoinitiated crosslinking can also be used to produce printing inks and 3D printing materials.

[0057] Low-molecular-weight variants of the polymer according to the invention are ideally suited as 3D printing materials for stereolithography (SLA) and digital light processing (DLP). These additive manufacturing technologies are based on the layer-by-layer curing of liquid resins using light and, when combined with conventional materials such as acrylates or epoxies, result in products that are not mechanically or solvolytically recyclable. In this case, the typical molecular weight is between 200 and 5,000 g / mol to ensure sufficient flowability of the unsaturated polyester.

[0058] A solvolytically recyclable 3D printing resin can, for example, contain the oligomeric main components of the polymer according to the invention, and further monomers such as trimethylolpropane triacrylate (TMPTA) or Ethylene glycol diacrylate (EGDA), which serve as diluents and reactive components, as well as photoinitiators.

[0059] The ester groups in the material represent predetermined breaking points that can be broken by solvolysis of aqueous or alcoholic mixtures, thus enabling chemical recycling of the material.

[0060] Monomeric and / or oligomeric building blocks for the synthesis of the rubber mixture of this invention can be obtained, for example, from the depolymerization of mcl PHA and / or Icl PHA. These mcl PHA or Icl PHA starting materials preferably have a molecular weight of 40,000 to 1,000,000 g / mol, preferably having a molecular weight of 60,000 to 200,000 g / mol. The depolymerization takes place in the presence of a diol, for example, ethylene glycol, under suitable reaction conditions to obtain unsaturated hydroxy-terminated mcl PHA and / or Icl PHA oligomeric building blocks. The oligomeric building blocks should have a molecular weight of 2,000-20,000 g / mol.

[0061] Monomeric and / or oligomeric units can be obtained from the rubber composition of this invention, and specifically a polymer of the general formula (I), by a depolymerization reaction.

[0062] In a first step, the vulcanized rubber mixture is placed in an alcoholic and / or aqueous reaction mixture.

[0063] The depolymerization of the vulcanized rubber mixture is then carried out by heating the reaction mixture at a temperature in the range of 20-400 °C for a specified period of time. Optionally, the depolymerization reaction can be carried out in the presence of a catalyst.

[0064] Monomeric and / or oligomeric units are then separated from the depolymerized reaction mixture.

[0065] Optionally, the separated monomeric and / or oligomeric units are purified to enable better processing of these units.

[0066] Ideally, depolymerization is carried out until monomers are obtained. Cross-linked or oligomeric units are preferably removed to obtain pure monomers. Compared to oligomers, monomers allow for more precise tuning of a new polycondensation. However, it is also possible to use oligomeric units for a new polycondensation.

[0067] Surprisingly, the various types of AA and BB monomers described above can be separated and purified from each other in high yield. The monomers that do not undergo any chemical change during vulcanization can be directly reused to produce a new vulcanizable polymer. The monomers with isolated or conjugated double bonds can be separated and used for other purposes.

[0068] The reaction mixture from the solvolysis of the polymer according to the invention typically consists of the monomeric units of formula (IV) and (V), but can also contain oligomeric units of formula (VI) to (HX). RO-(O=C)-D-(C=O)-OR (IV) HO-E-OH (V) RO-[-(O=C)-D-(C=O)-OEO-]k-(O=C)-D-(C=O)-OR (VI) HO-EO-[-(O=C)-D-(C=O)-OEO-]iH (VII), and RO-[-(O=C)-D-(C=O)-OEO-]mH (HX), where D has the molecular formula C W H X where the index w is an integer from the range 2 - 200, for example from 2 - 20, and the index x is an integer from the range 2 - 400, for example from 2 - 40, where B has the molecular formula C y H z wherein the index y is an integer from the range 2 - 200, for example from 2 - 20, and the index z is an integer from the range 2 - 400, for example from 2 - 40, wherein R is a hydrogen atom or a C1 to C10 alkyl group, and where the indices k, I and m are an integer in the range 1 - 50.

[0069] Insofar as a variant of the polymer according to the invention with repeating units of the general formula (II) and formula (III) has been solvolytically depolymerized, the reaction mixture also contains oligomeric and monomeric units of the formula (IX) to formula (X). RO-(O=C)-F-OH (IX) RO-[-(O=C)-FO-] p -H (X) where F has the molecular formula C q H r wherein the index q is an integer from the range 2-200, for example from 2-20, and the index r is an integer from the range 2-400, for example from 2-40. wherein R is a hydrogen atom or a C1 to C10 alkyl group, and wherein the index p is an integer from the range 1-50.

[0070] A and B can be freely selected in each repetition unit according to defined conditions.

[0071] A and B can be different, meaning they are not identical. However, A and B can also have an identical molecular formula but a different structure or arrangement.

[0072] Depending on the composition of the vulcanizable polymer, this results in a recycling rate of over 90% based on the carbon atoms. This represents a significant improvement over the recyclability of conventional rubbers.

[0073] The recycling process can be carried out with various alcoholic and aqueous mixtures. Industrially, the solvolysis of polymers is carried out with methanol, ethylene glycol, water, or mixtures of these substances.

[0074] The recycling process of the rubber mixture of this invention comprises a solvolysis step, separation and purification steps, and a repolymerization step. The repolymerized rubber material can then be revulcanized. Through this recycling process, a rubber material with equivalent properties of the original rubber mixture of this invention can be obtained.

[0075] Conventional vulcanizates cannot be converted into their monomers using the solvolysis described here and thus cannot be recycled.

[0076] The monomers can be separated and purified from each other, for example by distillation.

[0077] Another advantage of chemically recycling rubber is that fillers, which are often incorporated into rubber, also become accessible and can be reused. Typical additives in car tires include metals, carbon black, silica, antioxidants, and plasticizers.

[0078] Vulcanizates of polyesters made from asymmetric monomers are well known. Naturally derived PHA is an example of a polycondensate made from asymmetric (AB) monomers.

[0079] To obtain the vulcanizate from symmetrical monomers according to this invention from natural or asymmetrical PHA, the monomers must first be converted or modified to a symmetrical variant, for example, a diol variant. This symmetrical variant can then be converted in a step-growth polycondensation (AA + BB).

[0080] Compared to the symmetric monomers used here, the asymmetric monomers are generally not as easily and inexpensively accessible.

[0081] In contrast to symmetric monomers, which, as mentioned above, can be separated and purified in high yield, polymerized unsymmetric saturated and unsaturated monomers are chemically very similar. Therefore, they cannot be separated in high yields and purity using simple methods such as distillation, as is necessary for a recycling process. The system disclosed here therefore represents a significant improvement over the state of the art.

[0082] The ester groups, which act as predetermined breaking points, can be broken down by enzymes in addition to the solvolysis process. This enables biodegradation of the vulcanizate. Biodegradation is favored by the amorphous nature of rubber and, in the case of car tires, by the large specific surface area of ​​the microplastics created by tire wear.

[0083] For variants of the polymer according to the invention containing unsaturated moieties of mcl PHA, the ester bond density and consequently the biotic and abiotic degradability of the vulcanizate is increased, making this variant suitable for mechanically less demanding applications such as shoe soles and offering potential for compostability of the rubber or the recirculation of recycling streams into the biosynthesis of mcl PHA and / or Icl PHA of the rubber.

[0084] Synthetic rubbers in particular are known to degrade very slowly in the environment.

[0085] In the polymers of formula (I) described here, a low ester bond density results in a hydrophobic material. This minimizes abiotic hydrolysis of the entire polyester under aqueous conditions, ensuring the usability of the material disclosed here over a longer period of time. Enzymatic degradation, as a surface-directed degradation mechanism, only becomes relevant upon the formation of particles with a greatly increased specific surface area, without significantly affecting the stability of the desired product beforehand.

[0086] Many products, especially car tires, consist of a mixture of different rubbers, as this allows for the creation of desired property profiles. The invention includes mixtures consisting of 1-99 wt.% or 50-95 wt.% of the polymer of general formula (I). In one embodiment, the rubber mixture contains no other rubber component. The rubber mixture may also contain one or more polymers of general formula (I), as well as polymers of general formula (II) and / or general formula (III), as the sole rubber components.

[0087] In an alternative embodiment, the rubber mixture contains, in addition to the polymer of general formula (I), 1 - 99 wt.% of one or more rubber components selected from natural rubber, styrene-butadiene copolymers (SBR), polybutadiene (BR), polyisoprene, isobutylene-isoprene copolymers, ethylene-propylene-diene copolymers, acrylonitrile-butadiene copolymers (NBR), chloroprene, fluororubber, acrylic rubber, silicone rubber, ethylene-vinyl acetate copolymer (EVA) polyolefin elastomer, and short-chain (sei) PHA, mcl PHA, and lcl PHA, as well as mixtures thereof.

[0088] The rubber mixture of this invention may, for example, comprise 1-5 wt.% of a polymer of general formula (I). In this case, the polymer serves as a compatibilizer.

[0089] The rubber mixture of this invention may, for example, comprise 20-50 wt.% of a polymer of general formula (I). In this case, the polymer is used as a blend component.

[0090] The rubber mixture of this invention may, for example, comprise more than 50-99 wt.% of a polymer of general formula (I). In this case, the polymer is used as the main component.

[0091] The invention further relates to the use of the material presented here for the manufacture of tires, drive belts, toys, sealing material, dampers, brakes, membranes, valves, clothing, hoses, chewing gum, bags, shoes, mats, medical, cosmetic and sanitary articles, gloves and rubber bands. Short description of the characters The invention is explained in more detail with reference to the attached figures, in which Fig. 1 shows a cyclic stress-strain diagram obtained on a tensile test specimen according to ISO 527-2, Type 5A, Fig. 2 the degree of mineralization of the added 13 C-carbon in % (Y-axis) over the duration of the experiment in days X-axis, Fig. 3 an example of a mcl PHA according to general formula (II), Fig. 4 an example of a mcl PHA according to general formula (III), and Fig. 5 an example of the repeating unit «G» of the general formula (II). Examples of implementation

[0092] The present invention will now be explained in detail by way of examples, but the present invention is not limited thereto. , vulcanizable

[0093] In a typical polycondensation reaction to produce an amorphous, unsaturated and thus vulcanizable polyester, the Monomers Pripol 1009 dimer acid (1 equivalent), hexenedioic acid (1 Equivalent) and ethylene glycol (4 equivalents) together with the Catalyst DBTO (0.02 equivalents) and stabilizer BHT (1 weight %) were added to a round-bottomed flask.

[0094] The mixture was degassed and heated to 140 °C while stirring. Excess ethylene glycol and water resulting from the condensation reaction were removed by distillation. After 4 hours, a vacuum was gradually applied until a vacuum of 0.05 mbar was reached after 24 hours. The reaction was continued at 0.05 mbar and 140 °C for approximately 2 days until the polymer was no longer flowable due to its high viscosity. The temperature was then increased to 160 °C for 4 hours, and the reaction was subsequently stopped by cooling to room temperature. The synthesized polymer was 1 Dog 13 C-Nuclear Magnetic Resonance Spectroscopy ( 13 C-NMR), gel permeation Chromatography (GPC) and Differential Scanning Calorimetry (DSC). The polyester was a highly viscous, completely amorphous Material with a glass transition point of approximately -50 °C, a number-average molecular weight of approximately 40,000 g / mol, and a weight-average molecular weight of approximately 130,000 g / mol. Double bonds of the unsaturated monomer hexenedioic acid were retained during the synthesis, as demonstrated by NMR.

[0095] The chemical structure of Pripol 1009 consists of a C36 carbon skeleton with two carboxyl groups and possible branching or ring systems resulting from the dimerization of unsaturated fatty acids. The remaining double bonds are usually hydrogenated.

[0096] The Pripol 1009 used was made from rapeseed oil, in which C18 was dimerized to C36. However, the use of other, particularly longer, dimerized fatty acids is also possible. In general, all dimerized fatty acids from other sources can be used here. Example 2 - Vulcanization of an amorphous, unsaturated polyester

[0097] The amorphous, unsaturated polyester described above was crosslinked without further processing steps after conventional vulcanization. For this purpose, the uncrosslinked rubber (100 parts per hundred rubber (phr)) was mixed with sulfur (2.75 phr), TBBS (0.8 phr), and zinc oxide (5 phr) at approximately 100 °C. The mixture was poured into a mold and vulcanized at 180 °C for 1 h. The resulting material was characterized by DSC and tensile-strain experiments. The vulcanizate was insoluble, infusible, and exhibited rubber-like behavior comparable in quality to a commercially available rubber.

[0098] Figure 1 shows a cyclic stress-strain diagram performed on a tensile-strain test specimen according to ISO 527-2, Type 5A. The x-axis indicates strain in %; the y-axis indicates stress in MPa. The cyclic stress-strain test clearly demonstrates the elastic, rubber-like nature of the resulting material. of the vulcanizate

[0099] To depolymerize the vulcanized polyester, it was added to approximately 10 times the amount of methanol and stirred in a pressure reactor at 150 °C for 6 days. The resulting homogeneous, brown suspension was filtered, the solvent removed under reduced pressure, and then distilled, separating three fractions. Fraction 1 was an ethylene glycol-rich mixture and was obtained at 5 mbar (i.e., 500 Pa) and a temperature of 110-130 °C. Fraction 2 consisted primarily of the crosslinked and uncrosslinked hexenedioic acid monomers and was obtained at 0.05 mbar (i.e., 5 Pa) and a temperature of 220 °C. At 0.05 mbar (i.e., 5 Pa) and a temperature of 250-300 °C, pure dimethyl dimer was isolated in fraction 3 with a yield of 98%. The isolated monomer has a purity of over 99%, as determined by NMR. The recycled Dimethyl dimer ester was successfully used for a resynthesis of the amorphous polyester described above. Degradability study in soil at 25 °C

[0100] An amorphous, unsaturated polyester was synthesized as described in Example 1 and vulcanized as described in Example 2. During the synthesis 13 C-labeled ethylene glycol was used. The resulting PC-labeled material was tested in a degradation experiment in agricultural soil at 25 °C in the dark in triplicates compared to cellulose as a control. 13 C-labeled CO2 could be selectively quantified in an apparatus as described by TF Nelson (Nelson, TF, Baumgartner, R., Jaggi, M. et al. Nat Commun, 2022, 13, 5691).

[0101] Figure 2 shows on the Y-axis the degree of mineralization of the added 13C-carbon in % and on the X-axis the duration of the test in days (d). After about 90 days, a mineralization of about 30% can be detected. This shows that the material can be biologically depolymerized and the 13 C-labeled monomers are mineralized. Cellulose was used as a biodegradable reference under treated under the same conditions and reached a mineralization of 60 - 75 % after 90 days. mcl PHA with a

[0102] In a typical degradation reaction for the production of hydroxy-terminated mcl PHA with a molecular weight of 2,000–20,000 g / mol, mcl and / or be PHA with an average molecular weight of 80,000 g / mol and a content of 10% unsaturated side chains was used. The polymer was placed in a round-bottomed flask in an aprotic solvent such as chloroform, toluene, or xylene at a concentration of 10% w / v. Ethylene glycol was added to the solution in a 1:1 molar ratio to the end groups of the mcl PHA, as well as sulfuric acid as a catalyst (0.5–1 wt%). The mixture was heated to 100–120°C with stirring and maintained at this temperature for 4–6 hours. The reaction progress was monitored periodically by sampling and molecular weight analysis using GPC. Alternatively, the reaction was carried out in a continuous extrusion process to avoid the use of additional solvents.

[0103] Upon reaching the desired molecular weight of 2,000-20,000 g / mol, the reaction mixture is cooled to room temperature. Deionized water is added or the extrudate is passed into a water bath to stop the reaction and dilute the acid. The mixture is neutralized with sodium bicarbonate until neutral. The phases are separated in a separatory funnel, the organic phase is washed several times with deionized water to remove any remaining acids or salts, and dried over anhydrous magnesium sulfate. The solvent is removed to isolate the hydroxy-terminated mcl PHA. The product is dried under vacuum at room temperature to remove any remaining solvents. The final product is characterized by GPC to ensure that the molecular weight is in the desired range of 2,000-20,000 g / mol. Example 6 - Synthesis of an amorphous, unsaturated, vulcanizable polyester with mcl PHA

[0104] In a typical polycondensation reaction to produce an amorphous, unsaturated, and thus vulcanizable polyester, the monomers Pripol dimer acid (1 equivalent), hydroxy-terminated mcl PHA (1 equivalent), and ethylene glycol (2 equivalents) were added to a round-bottom flask along with the catalyst dibutyltin oxide (DBTO) (0.02 equivalents) and the stabilizer butylhydroxytoluene (BHT) (1 wt%). The mixture was degassed and heated to 140 °C with stirring. Excess ethylene glycol and water formed during the condensation reaction were removed by distillation. After 4 hours, a vacuum was gradually applied until a vacuum of 0.05 mbar, i.e., 5 Pa, was reached after 24 h. At 0.05 mbar, i.e. 5 Pa, and 140 °C, the reaction is continued for 2 days until the polymer is no longer flowable due to its high viscosity.The temperature was then raised to 160 °C for 4 h, and the reaction was then terminated by cooling to room temperature. The synthesized polymer was then 1 Dog 13 C NMR, GPC, and DSC were used. The polyester was a highly viscous, completely amorphous material with a glass transition point of approximately -50 °C, a number-average molecular weight of approximately 40,000 g / mol, and a weight-average molecular weight of approximately 130,000 g / mol. The double bonds of the unsaturated side chains of the mcl PHA were retained during synthesis, as demonstrated by NMR.

Claims

Patent claims 1. A rubber mixture containing a polymer component according to formula (I) [-(O=C)-A-(C=O)-OBO-] n (I), where A has the molecular formula C c Hd, where the index c is an integer from the range 2 - 200, for example from 2 - 20, and the index d is an integer from the range 2 - 400, for example from 2 - 40, where B has the molecular formula C e Hf comprises, wherein the index e is an integer from the range 2 - 200, for example from 2 - 20, and the index f is an integer from the range 2 - 400, for example from 2 - 40, wherein at least one of the components A or B does not contain an isolated or conjugated double bond, wherein at least one of the components A or B contains an isolated or conjugated double bond, and wherein the index n is an integer from the range 5 - 50,000.

2. The rubber mixture according to claim 1, which comprises 1-99% by weight, or 50-95% by weight, of a polymer component according to formula (I).

3. The rubber mixture according to claim 1 or 2, comprising a further polymer component according to formula (II) HO-GO-[-(O=C)-AO-(C=O)-BO-] n -H (ID, and / or another polymer component according to formula (III) HO-[-(O=C)-AO-(C=O)-BO-]nH (III), where A has the molecular formula C c Hd, where the index c is an integer from the range 2 - 200, for example from 2 - 20, and the index d is an integer from the range 2 - 400, for example from 2 - 40, where B has the molecular formula C eHf, wherein the index e is an integer from the range of 2 - 200, for example from 2 - 20, and the index f is an integer from the range of 2 - 400, for example from 2 - 40, wherein at least one of the components A or B does not contain an isolated or conjugated double bond and wherein at least one of the components A or B contains an isolated or conjugated double bond and the index n is an integer from the range of 5 - 50,000, wherein G has the empirical formula C g Hh, where the index is an integer from the range 2-50, where the index h is an integer from the range 4-100.

4. The rubber mixture according to claim 3, comprising hydroxy-terminated medium-chain (mcl) polyhydroxyalkanoate (PHA) and / or long-chain (Icl) PHA as a building block of a polymer component according to the general formula (II) and / or according to the general formula (III) HO-GO-[-(O=C)-AO-(C=O)-BO-] n -H (II) HO-[-(O=C)-AO-(C=O)-BO-]nH (HI).

5. The rubber mixture according to any one of claims 1 to 4, comprising one or more polymers of the general formula (I), and optionally, of the general formula (II) and / or of the general formula (III), as the sole rubber components.

6. The rubber mixture according to any one of claims 1 to 4, comprising (i) a first rubber component comprising 1-99 wt.% of one or more polymers selected from a group consisting of the general formula (I), and, optionally, the general formula (II) and / or the general formula (III), and (ii) a second rubber component comprising 1-99 wt.% of one or more polymers selected from a group consisting of natural rubber, styrene-butadiene copolymers (SBR), polybutadiene (BR), polyisoprene, isobutylene-isoprene copolymers, ethylene-propylene-diene copolymers, acrylonitrile-butadiene copolymers (NBR), chloroprene, fluororubber, acrylic rubber, silicone rubber, ethylene-vinyl acetate copolymer (EVA), polyolefin elastomer, and short-chain (sei) PHA, mcl PHA, and lcl PHA.

7. A rubber mixture according to claim 1 to 6 having a glass transition point of -150 °C to +50 °C.

8. Use of the rubber mixture according to one of claims 1 to 7 for the production of tires, drive belts, toys, sealing material, dampers, brakes, membranes, valves, clothing, hoses, chewing gum, bags, shoes, mats, adhesives, medical, cosmetic and sanitary articles, gloves and rubber bands.

9. A process for producing the rubber mixture according to any one of claims 1 to 7, comprising the following steps: (i) Providing monomeric or oligomeric building blocks selected from a group consisting of monomeric or oligomeric building blocks of one or more of the general formulas (II) and / or (IV) to (HX) HO-GO-[-(O=C)-AO-(C=O)-BO-] n -H (II) RO-(O=C)-D-(C=O)-OR (IV) HO-E-OH (V) RO-[-(O=C)-D-(C=O)-OEO-]k-(O=C)-D-(C=O)-OR (VI) HO-EO-[-(O=C)-D-(C=O)-OEO-]iH (VII), and RO-[-(O=C)-D-(C=O)-OEO-] m -H (HX), in a reaction solution, (ii) reacting the reaction solution under suitable reaction conditions for a certain period of time to carry out a polycondensation reaction of the monomeric or oligomeric building blocks to form a polymer of the general formula (I), (iii) crosslinking the polymer of general formula (I) by adding a photoinitiator and / or a vulcanizing agent containing, for example, sulfur, a peroxide, or an azo initiator.

10. The process of claim 9, further comprising the step of mixing the polymer of formula (I) with a polymer of formula (III) before or in the step of crosslinking the polymer.

11. The method according to claim 9 or 10, further comprising adding a chemical foaming agent, other additives and / or fillers in the crosslinking step.

12. The method according to any one of claims 9 to 11, further comprising TI - Depolymerizing mcl PHA and / or Icl PHA, preferably having a molecular weight of 40,000 to 1,000,000 g / mol, or having a molecular weight of 60,000 to 200,000 g / mol, in the presence of a diol, for example ethylene glycol, under suitable reaction conditions to obtain unsaturated hydroxy-terminated mcl PHA and / or Icl PHA oligomeric building blocks of a polymer component according to the general formula (II) or according to the general formula (III), wherein the oligomeric building blocks have a molecular weight of 2,000-20,000 g / mol, - Adding the obtained unsaturated hydroxy-terminated mcl PHA and / or Icl PHA oligomeric assembly to the reaction solution as a diol component for the polycondensation to a polymer of formula (I).

13. A process for the preparation of monomeric and / or oligomeric units from a vulcanized rubber mixture according to any one of claims 1 to 7, comprising: (i) providing the vulcanized rubber mixture according to any one of claims 1 to 7 in an alcoholic and / or aqueous reaction mixture, (ii) depolymerisation of the vulcanised rubber mixture by heating the reaction mixture at a temperature in the range of 20 - 400 °C for a certain period of time, (iii) separating monomeric and / or oligomeric units from the reaction mixture, and (iv) Optionally, purification of the separated monomeric and / or oligomeric units.

14. The process according to claim 13, wherein all or at least some of the monomeric and / or oligomeric units in a group consisting of the general formulas (IV) to (IIX) RO-(O=C)-D-(C=O)-OR (IV) HO-E-OH (V) RO-[-(O=C)-D-(C=O)-OEO-] k -(O=C)-D-(C=O)-OR (VI) HO-EO-[-(O=C)-D-(C=O)-OEO-]iH (VII), and RO-[-(O=C)-D-(C=O)-OEO-]mH (IIX), where D has the molecular formula C W H X where the index w is an integer from the range 2 - 200, for example from 2 - 20, and the index x is an integer from the range 2 - 400, for example from 2 - 40, where B is the molecular formula C y H z wherein the index y is an integer from the range 2 - 200, for example from 2 - 20, and the index z is an integer from the range 2 - 400, for example from 2 - 40, wherein R is a hydrogen atom or a C1 to C10 alkyl group, and wherein the indices k, l and m are an integer from the range 1 - 50.

15. A process according to claim 14, wherein all or at least part of the monomeric and / or oligomeric units in a group consisting of the general formulas (IX) and formula (X) RO-(O=C)-F-OH (IX), and RO-[-(O=C)-FO-] p-H (X), where F has the molecular formula C q H r where the index q is an integer from the range 2 - 200, for example from 2 - 20, and the Index r is an integer from the range 2 - 400, for example from 2 - 40. Where R is a hydrogen atom or a C1 to C10 alkyl group, and where the index p is an integer from the range 1 - 50.

16. A process for recycling a rubber mixture according to any one of claims 1 to 7, comprising - Depolymerizing the rubber mixture according to one of the claims 1 to 7 in a reaction process according to any one of claims 13 to 15 comprising the step of purifying the separated monomeric and / or oligomeric units, and - Producing the rubber mixture according to one of claims 1 to 7 according to the polycondensation process according to one of claims 9 to 11.

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