Rubber mixtures for recyclable and biodegradable rubber

Abstract

The present invention relates to a rubber mixture comprising a polyester containing at least one saturated and unsaturated monomer, which can be processed into a rubbery vulcanized product that is biodegradable by the contained ester bonds, and to a method for producing this rubber mixture. The present invention also relates to a method for recycling, comprising a dissolution and decomposition step, a separation and purification step, and a repolymerization of the obtained monomers and / or oligomers.

Description

[Technical Field]

[0001] Technical field The present invention relates to vulcanizable or crosslinkable rubber compounding for polyester-based recyclable and biodegradable elastomers, its use, and a method for recycling the same. [Background technology]

[0002] Latest technology Vulcanized mixtures or rubbers are among the most widely produced polymer materials. This is because their excellent mechanical and thermal properties make them ideal materials for applications such as automobile tires. The most commonly used rubbers include natural rubber, styrene-butadiene copolymer (SBR), polybutadiene (BR), and polyisoprene. Most of these are amorphous polymers, and elastic materials are produced by crosslinking or vulcanization, for example, using sulfur, peroxides, or azo initiators.

[0003] Currently, only a small fraction of the rubber produced is recycled, and it decomposes very slowly in the environment. This is a significant environmental problem due to the enormous production volume of millions of tons, and it also highlights the issue of vast resources that cannot be reused.

[0004] A closed-loop material cycle is desirable. This allows for the creation of value from waste and reduces the release of harmful substances into the environment. Furthermore, by reusing raw materials, it can prevent the use of limited fossil fuels.

[0005] Mechanical recycling has been successfully implemented for many polymers, such as HDPE and PET. However, vulcanized materials are thermosetting plastics and cannot be melted, so they cannot be recycled using this method.

[0006] Chemical recycling of polymers involves breaking down the chain into its basic components or monomers and then remanufacturing materials with the same properties from them. For polymers with specific break points, such as ester groups, such as PET, chemical recycling is carried out industrially through a dissolution and decomposition process.

[0007] One method for recycling polymers without break points is pyrolysis. Using high energy and catalysts, the polymer chains are broken down, converting the solid polymer into liquid and / or gaseous molecules. This results in a statistically mixed product, which typically cannot be directly used for polymerization into substances with the same properties. Often, the product is then thermally recycled. With appropriate catalysis, specific monomers can be produced. These catalysts are usually highly sensitive to contaminants and foreign atoms such as sulfur. Currently, a closed-loop material cycle of rubber by pyrolysis is not feasible.

[0008] As illustrated by the example of automobile tires, the material recycling of vulcanized materials is best described as downcycling, as it results in lower-value products. Primarily, crushed automobile tires are mixed into asphalt or used as fillers. Desulfurization selectively breaks sulfur crosslinks in rubber. Desulfurized rubber can be mixed with newly manufactured rubber for use in rubber production, although its properties are reduced in this case. Furthermore, products such as tartan tracks and rubber mats can also be manufactured.

[0009] There are several concepts for manufacturing recyclable elastomers. These include thermoplastic elastomers (TPEs) and vitrimers. TPEs are manufactured and used industrially and are mechanically recyclable, but they have several drawbacks compared to vulcanized materials. Generally, they are expensive to manufacture, have low thermal and mechanical stability, develop creep after long-term use, and generally cannot be used in automotive tires because fillers such as carbon black cannot be added.

[0010] Furthermore, a renewable polyester network with elastic properties can also be produced by the polycondensation of bifunctional and polyfunctional monomers. This network is generated in a time-consuming synthesis process rather than by relatively rapid vulcanization like rubber. Since the cross-linked polymer is insoluble and non-melting, the polycondensation needs to be carried out in the shape of the parts to be manufactured. Such a process is not scalable, very costly and time-consuming, and is not suitable for industrial applications.

[0011] Due to the wear of automobile tires, rubber is released into the environment in the form of microplastics. Microplastics are often absorbed by organisms. Humans may ingest microplastics through breathing and the food chain. Ingestion of microplastics is thought to cause various health problems, such as acting as a medium to carry hydrophobic substances toxic to the human body. Biodegradable elastomers, especially rubber, are one way to address the accumulation of microplastics and the associated adverse effects on humans and the environment.

Summary of the Invention

Problems to be Solved by the Invention

[0012] Summary of the Invention [[ID= sixteen]]Thus, it was an issue to provide a material having the properties of vulcanizates known in this technical field and capable of being processed in a similar manner.

[0013] Furthermore, an economical process is also needed that can recover valuable oligomers and / or monomeric building blocks of the starting material from the vulcanized material.

[0014] Ideally, the chemical composition of the polymer according to the present invention should be designed such that microplastics inevitably generated by wear are decomposed in the environment.

Means for Solving the Problems

[0015] One or more of the above problems are solved by a vulcanized rubber mixture (vulcanizable rubber compound) for producing a rubber-like vulcanizate according to the present invention.

[0016] The polymer contained in the rubber mixture is represented by the following formula. [-(O=C)-A-(C=O)-O-B-O-]

[0017] (I) Here, A contains the molecular formula C c H d where the exponent c is an integer in the range of 2 to 200, for example, in the range of 2 to 20, and the exponent d is an integer in the range of 2 to 400, for example, in the range of 2 to 40. B contains the molecular formula C e H f where the exponent e is an integer in the range of 2 to 200, for example, in the range of 2 to 20, and the exponent f is an integer in the range of 2 to 400, for example, in the range of 2 to 40. At least one of the components A or B does not contain an isolated double bond or a conjugated double bond, and at least one of the components A or B contains an isolated double bond or a conjugated double bond. The exponent n is an integer in the range of 5 to 50,000. A and B can be freely selected for each repeating unit according to the defined conditions.

[0017] A and B may be different, that is, not the same. However, A and B may have the same molecular formula but different structures or arrangements. <00001​​​​​​​​​​​​​​Polymers derived from the repeating unit [-(O=C)-A-(C=O)-OBO-] are -[-AA-BB-]-type polyesters. AA and BB represent the same functional groups in the monomers. -[-AA-BB-]-type polyesters are obtained by stepwise-growth polycondensation of AA monomers, e.g., diols (HO-(O=C)-A-(C=O)-OH) or diol esters (RO-(O=C)-A-(C=O)-OR) and BB monomers, e.g., diols (HO-B-OH).

[0022] Because it contains ester groups, this material is chemically recyclable or biodegradable through dissolution and decomposition.

[0023] Therefore, the polyester represented by formula (I) is a diol, diacid, or diester and is composed of at least two monomers, AA and BB. At least one monomer has an isolated or conjugated double bond, and at least one monomer does not have an isolated or conjugated double bond. Thus, the synthesized polymer contains monomers of the type that crosslink at the double bond position during vulcanization (containing an isolated or conjugated double bond) and other types of monomers that do not undergo any chemical reaction during vulcanization (not containing an isolated or conjugated double bond).

[0024] Examples of saturated monomers include hydrogenated dimeric fatty acids, ethylene glycol, dibutylmalonic acid, and saturated glycol-modified polyhydroxy fatty acids.

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

[0026] Unsaturated monomers are preferably composed of C4-C6 compounds to maximize their recyclability. Unsaturated polyhydroxy fatty acid oligomers are characterized by C4-C9 monomer units, with varying proportions of terminal double bonds in the side chains.

[0027] Ideally, saturated monomers should produce hydrophobic, amorphous polymers while simultaneously being easily separable from other monomers. Furthermore, they should be inexpensive and readily available.

[0028] This invention also covers bio-based substances such as monomeric dimeric fatty acids, ethylene glycol, itaconic acid, and special polyhydroxy fatty acids, also known as polyhydroxy fatty acids (PHAs).

[0029] As one variation, the present invention relates to the use and modification of unsaturated medium-chain (mcl)PHA having carbon side chains of C6 to C14 per monomer unit, or long-chain (lcl)PHA having monomer units with more than 15 carbon atoms.

[0030] Unsaturated mclPHA and / or lclPHA can be produced by fermentation of natural or recombinant bacterial strains, such as Pseudomonas putida KTQQ20 and Pseudomonas entomophila LAC23. These strains can produce PHA with functional groups in the side chains when given fatty acids containing functional groups such as double or triple bonds, epoxy groups, carbonyl groups, cyano groups, phenyl groups, and halogen groups.

[0031] In particular, mclPHA and lclPHA containing separated internal or terminal double bonds in the side chains are of interest to the polymers of the present invention.

[0032] mclPHA and lclPHA have low crystallinity due to their high side-chain density and can exist in both semi-crystalline and amorphous forms. These properties make them particularly suitable as oligomers and polymer building blocks for producing the polymer block copolymers of the present invention, or as mixing and crosslinking partners. The average molecular weight of the modified hydroxy-terminated unsaturated polyhydroxyalkanoates is 2,000 to 200,000 g / mol, preferably 2,000 to 20,000 g / mol.

[0033] Hydroxylation and functionalization of end groups, such as acid-catalyzed depolymerization with ethylene glycol, play important roles in the production of these oligomer constituent blocks. Hydroxylation modifies the functional groups of PHA. Depolymerization allows for the controlled decomposition of PHA into defined hydroxyl-terminated oligomers, which can be used as constituent blocks in block copolymers and AA / BB polycondensations.

[0034] The hydroxyl-terminated mclPHA and / or lclPHA used in polycondensation are represented by the following formula: HO-GO-[-(O=C)-AO-(C=O)-BO-] n -H (II)

[0035] Because this polymer is manufactured by conventional polycondensation, key parameters of the polymer, such as double bond density, ester bond density, and aromatic monomer incorporation, can be easily adjusted.

[0036] Polycondensation is catalyzed at a temperature of 100 to 350°C, preferably 120 to 180°C.

[0037] Ester bond density, in particular, affects the polarity, degradability, and miscibility with other polymers and elastomers of a polymer. Therefore, MclPHA increases the ester bond density of a polymer, significantly impacting its material properties.

[0038] At the same time, since the ester bond density increases the degradability of the material, the variant of the PHA-containing polymer according to the present invention becomes more susceptible to hydrolysis and enzymatic degradation in the natural environment.

[0039] In an advantageous embodiment of the invention, the mcl PHA and / or lcl PHA of formula (III) are used as mixing partners in the rubber mixture and / or the hydroxy-terminated mcl PHA and / or lcl PHA of formula (II) are used as oligomeric building blocks for polycondensation in the production of rubber materials. HO-G-O-[-(O=C)-A-O-(C=O)-B-O-] n -H (II) HO-[-(O=C)-A-O-(C=O)-B-O-] n -H (III) Here, A has the molecular formula C c H d where the exponent c is an integer in the range of 2 to 200, for example an integer in the range of 2 to 20, the exponent d is an integer in the range of 2 to 400, for example an integer in the range of 2 to 40, B has the molecular formula C e H f where the exponent e is an integer in the range of 2 to 200, for example an integer in the range of 2 to 20, the exponent f is an integer in the range of 2 to 400, for example an integer in the range of 2 to 40, at least one of the components A or B does not contain isolated or conjugated double bonds, at least one of the components A or B contains isolated or conjugated double bonds, the exponent n is an integer in the range of 5 to 50000, G has the molecular formula C g H h where the exponent g is an integer in the range of 2 to 50 and the exponent h is an integer in the range of 4 to 100, and A and B can be freely selected for each repeating unit according to the defined conditions.

[0040] A and B can be different, that is, they may not be the same. However, A and B may have the same molecular formula but different structures or sequences.

[0041] Examples of possible repeating units G are shown in FIG. 5. With this repeating unit, further diols can be introduced into the polymer structure.

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

[0043] Polymers of general formula (II) can be obtained, for example, from the depolymerization reaction of unsaturated mclPHA polymers of general formula (II).

[0044] Possible examples of hydroxy-terminated, glycol-modified, unsaturated mclPHAs of general formula (II) are shown in Figure 3.

[0045] Polymers of general formula (III) can be used as mixing and / or crosslinking partners for polymers of general formula (I).

[0046] Possible examples of polymers of general formula (III) are shown in Figure 4.

[0047] The polymer according to the present invention preferably exhibits less than 20% crystallinity, and ideally, the polymer is completely amorphous. This can be achieved by using dimeric fatty acids and branched monomers of mclPHA and / or lclPHA.

[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 temperature of the polymer is between -150 and 50°C, for example, between -150 and -40°C.

[0050] Polymers produced by this method can be vulcanized using conventional techniques, such as conventional vulcanization with sulfur and other additives, to become elastic, rubber-like materials. Therefore, they are compatible with existing manufacturing processes and can be used, for example, in the manufacture of automobile tires.

[0051] Other additives that may be added include oxidation stabilizers, foam stabilizers, plasticizers, compatibilizers, UV stabilizers, colorants, inorganic fillers, or biofillers such as olive husk powder, walnut husk powder, and / or rice husk ash (RHA).

[0052] The unsaturated polyester produced by this method can be crosslinked with organic peroxides, such as dicumyl peroxide or dilauryl peroxide, or with azo initiators such as AIBN, and other additives as needed.

[0053] By using chemical foaming agents, such as azodicarbonamide and sodium bicarbonate, or by performing vulcanization or crosslinking using a physical foaming process, it becomes possible to manufacture foamed elastic products such as mattresses, shoe soles for the sports shoe industry, and water sports equipment.

[0054] The polymer crosslinking according to the present invention can also be carried out by using a photoinitiator. A photoinitiator is a substance that generates radicals when exposed to ultraviolet or visible light, and these radicals initiate polymerization and crosslinking of polymer chains. Common photoinitiators include benzoin ethers, benzyl ketals, and acylphosphine oxides. This enables potential applications such as the production of UV-curable adhesives for the electronics industry, dental and medical technologies, and specialty packaging materials that are reversible and biodegradable.

[0055] Furthermore, photo-initiated crosslinking can also be used to manufacture coatings and paints with high abrasion resistance and chemical resistance. These properties are particularly important in the automotive, furniture coating, and construction industries.

[0056] Finally, photoinitiated crosslinking can also be used in the manufacture of printing inks and 3D printing materials.

[0057] The low-molecular-weight polymer variants according to the present invention are highly suitable as 3D printing materials for stereolithography (SLA) and digital light processing (DLP). These additive manufacturing techniques are based on the curing of liquid resins layer by layer with light, and using conventional materials such as acrylates and epoxys results in products that are mechanically and solublely unrecyclable. In this case, the typical molecular weight is between 200 and 5000 g / mol to ensure sufficient fluidity in the unsaturated polyester.

[0058] For example, a soluble, recyclable 3D printing resin according to the present invention comprises an oligomer main component of the polymer, as well as monomers such as trimethylolpropane triacrylate (TMPTA) or ethylene glycol diacrylate (EGDA) which function as a diluent and reactive component, and a photoinitiator.

[0059] The ester groups in this material become breakpoints that are cleaved by solvent decomposition in aqueous solutions or alcohol mixtures, enabling the chemical recycling of the material.

[0060] The monomer and / or oligomer constituent blocks for the synthesis of the rubber mixture of the present invention can be obtained, for example, from the depolymerization of mclPHA and / or lclPHA. Preferably, these mclPHA or lclPHA starting materials have a molecular weight of 40,000 to 1,000,000 g / mol, and more preferably 60,000 to 200,000 g / mol. In this case, depolymerization is carried out under appropriate reaction conditions, for example, in the presence of a diol such as ethylene glycol, to obtain unsaturated hydroxy-terminated mclPHA and / or lclPHA oligomer constituent blocks. The oligomer constituent blocks need to have a molecular weight of 2,000 to 20,000 g / mol.

[0061] Monomers and / or oligomer units can be obtained from the rubber mixture of the present invention, specifically from a polymer of general formula (I), by a depolymerization reaction.

[0062] As the first step, the vulcanized rubber mixture is added to an alcohol and / or aqueous reaction mixture.

[0063] Next, the reaction mixture is depolymerized by heating it at a temperature range of 20 to 400°C for a certain period of time. Optionally, the depolymerization reaction can also be carried out in the presence of a catalyst.

[0064] Subsequently, monomers and / or oligomer units are separated from the depolymerized reaction mixture.

[0065] Optionally, the separated monomers and / or oligomer units can be purified to improve their processability.

[0066] Ideally, depolymerization should be carried out until monomers are obtained. Crosslinks or oligomeric aggregates should preferably be removed to obtain pure monomers. Compared to oligomers, monomers allow for more precise control of the new polycondensation. However, it is also possible to use oligomeric structures for the new polycondensation.

[0067] Surprisingly, each of the aforementioned types of AA and BB monomers can be separated and purified in high yield. Monomers that do not undergo chemical changes during vulcanization can be directly reused in the production of new vulcanized polymers. Monomers with isolated or conjugated double bonds can be separated and used for other purposes.

[0068] The reaction mixture obtained by the solvent decomposition of polymers according to the present invention is usually composed of monomer units of formulas (IV) and (V), but formulas (VI) 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-] l -H (VII), and RO-[-(O=C)-D-(C=O)-OEO-] m -H (IIX), It can contain oligomeric units, Here, D is the molecular formula C w H x It has, Here, the exponent w is an integer in the range of 2 to 200, for example, an integer in the range of 2 to 20, and the exponent x is an integer in the range of 2 to 400, for example, an integer in the range of 2 to 40. Here, B is the molecular formula C y H z It has, Here, the exponent y is an integer in the range of 2 to 200, for example, an integer in the range of 2 to 20, and the exponent z is an integer in the range of 2 to 400, for example, an integer in the range of 2 to 40. Here, R is a hydrogen atom or an alkyl group from C1 to C10. Here, the exponents k, l, and m are integers in the range of 1 to 50.

[0069] When modified polymers of the present invention having repeating units of general formulas (II) and (III) are added and depolymerized using solvent, the reaction mixture also contains oligomer and monomer units of formulas (IX) to (X). RO-(O=C)-F-OH (IX) RO-[-(O=C)-FO-] p -H (X) Here, F is the molecular formula C q H r It has, The exponent q is an integer in the range of 2 to 200, for example, an integer in the range of 2 to 20, and the exponent r is an integer in the range of 2 to 400, for example, an integer in the range of 2 to 40. Here, R is a hydrogen atom or a C1-C10 alkyl group. Here, the exponent p is an integer in the range of 1 to 50.

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

[0071] A and B may be different, meaning they are not identical. However, A and B may have the same molecular formula but differ in structure or sequence.

[0072] Depending on the composition of the vulcanized polymer, a recycling rate of over 90% on a carbon-carbon basis can be achieved. This represents a significant improvement over the recyclability of conventional rubber.

[0073] Recycling processes can be carried out using various alcohol and aqueous solution mixtures. Industrially, solvolysis of polymers is performed using methanol, ethylene glycol, water, or mixtures of these substances.

[0074] The rubber mixture recycling process of this invention includes a solvolysis step, a separation and purification step, and a repolymerization step. The repolymerized rubber material can be vulcanized again. This recycling process has the advantage of obtaining a rubber material having properties equivalent to the original rubber mixture of the present invention.

[0075] Conventional vulcanized products cannot be converted back into their monomers by the solvolysis described here, and therefore cannot be recycled.

[0076] Monomers can be separated and purified, for example, by distillation.

[0077] Chemical recycling of rubber also has the advantage of recovering and making available again the fillers that are often incorporated into the rubber. Additives commonly used in automotive tires include metals, carbon black, silica, antioxidants, and plasticizers.

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

[0079] In order to obtain vulcanized products of symmetric monomers from naturally asymmetric PHA according to this invention, it is first necessary to convert or modify the monomer to a symmetric form, such as a diol form. This symmetric form can be converted by stepwise polycondensation (AA + BB).

[0080] Compared to the symmetric monomers used here, asymmetric monomers are generally more difficult to obtain and more expensive.

[0081] As mentioned above, in contrast to symmetric monomers that can be separated and purified in high yield, polymerized asymmetric saturated and unsaturated monomers are chemically very similar. Therefore, separation in high yield and high purity required for recycling processes cannot be achieved by simple methods such as distillation. Thus, the system disclosed herein represents a significant improvement over prior art.

[0082] The ester groups, which act as fracture points, can be broken down by enzymes in addition to the dissolution-decomposition process. This enables the biodegradation of the vulcanized product. Biodegradation is accelerated by the amorphous properties of rubber and, when used in automobile tires, by the large specific surface area of ​​microplastics generated by tire wear.

[0083] As a variation of the polymer according to the present invention, one containing an unsaturated portion of mclPHA improves the ester bond density and, consequently, the biodegradability and abiotic properties of the vulcanized product. Therefore, this variation is suitable for applications with low mechanical load, such as shoe soles, and offers the possibility of rubber composting or returning the recycled flow to the biosynthesis of mclPHA and / or lclPHA in rubber.

[0084] On the other hand, synthetic rubber, in particular, is known for its extremely slow degradation in the environment.

[0085] The polymer of formula (I) described herein is hydrophobic due to its low ester bond density. This minimizes abiotic hydrolysis of the entire polyester in an aqueous environment, enabling the long-term use of the disclosed material. Enzymatic degradation as a surface-controlled degradation mechanism is only relevant when particles with a significantly increased surface area are formed; until then, it does not significantly affect the stability of the product of interest.

[0086] Many products, particularly automotive tires, are constructed by mixing various rubbers to achieve a desired property profile. This invention relates to mixtures containing 1 to 99% by mass, or 50 to 95% by mass, of a polymer of general formula (I). In some embodiments, the rubber mixture contains no other rubber components. The rubber mixture may also contain one or more polymers of general formula (I) and general formula (II) and / or general formula (III) as the sole rubber components.

[0087] In another embodiment, the rubber mixture includes, in addition to the polymer of general formula (I), rubber components selected from natural rubber, styrene-butadiene copolymer (SBR), polybutadiene (BR), polyisoprene, isobutylene-isoprene copolymer, ethylene-propylene-diene copolymer, acrylonitrile-butadiene copolymer (NBR), chloroprene, fluororubber, acrylic rubber, silicone rubber, ethylene vinyl acetate copolymer (EVA), polyolefin elastomer, and short-chain (scl) PHA, mcl PHA, lcl PHA, and mixtures thereof.

[0088] The rubber mixture of this invention may contain, for example, 1 to 5% by mass of a polymer of general formula (I). In this case, the polymer functions as a compatibilizer.

[0089] The rubber mixture of this invention may contain, for example, 20 to 50% by mass of a polymer of general formula (I). In this case, the polymer is used as a mixed component.

[0090] The rubber mixture of this invention may contain, for example, 50 to 99% by mass of a polymer of general formula (I). In this case, the polymer is used as the main component.

[0091] Furthermore, the present invention also relates to the use of the materials described herein in the manufacture of tires, drive belts, toys, seals, dampers, brakes, membranes, valves, clothing, hoses, chewing gum, bags, shoes, mats, medical supplies, cosmetics, hygiene products, gloves, and rubber bands.

[0092] Brief explanation of the drawing The present invention will be described in more detail with reference to the accompanying drawings. [Brief explanation of the drawing]

[0093] [Figure 1] Figure 1 shows the cyclic stress-strain curves performed on a tensile elongation test specimen according to ISO 527-2, type 5A. [Figure 2] Figure 2 shows the degree of mineralization (Y axis) of added 13C carbon during the test period (X axis). [Figure 3] Figure 3 shows an example of mclPHA using general formula (II). [Figure 4] Figure 4 shows an example of mclPHA using the general formula (III). [Figure 5] Figure 5 shows an example of the repeating unit "G" of general formula (II). [Examples]

[0094] The present invention will be described in detail below using examples. However, the present invention is not limited to these examples.

[0095] Example 1 - Amorphous, unsaturated, vulcanized polyester In a typical polycondensation reaction for producing amorphous, unsaturated, and therefore vulcanized polyesters, the monomers Pripol 1009 dimethane acid (1 equivalent), hexanoic acid (1 equivalent), and ethylene glycol (4 equivalents) were placed in a round-bottom flask together with the catalyst DBTO (0.02 equivalents) and the stabilizer BHT (1% by mass).

[0096] The mixture was degassed and heated to 140°C with stirring. Excess ethylene glycol and water produced by condensation were separated by distillation. The pressure was gradually reduced until a vacuum of 0.05 mbar was reached after 4 hours and 24 hours. The reaction was continued for approximately 2 days under conditions of 0.05 mbar and 140°C until the polymer viscosity increased and fluidity was lost. The temperature was then increased to 160°C for 4 hours and cooled to room temperature to terminate the reaction. The synthesized polymer was, 1 H and 13 C nuclear magnetic resonance spectroscopy ( 13 The material was analyzed using 13C-NMR, gel permeation chromatography (GPC), and differential scanning calorimetry (DSC). This polyester was a highly viscous, perfectly amorphous material with a glass transition temperature 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. NMR confirmed that the double bond of the unsaturated monomer hexenoic acid was maintained during synthesis.

[0097] The chemical structure of Pripol 1009 consists of a C36 carbon skeleton with two carboxyl groups, which can have branched or cyclic structures resulting from the dimerization of unsaturated fatty acids. Other double bonds are typically hydrogenated.

[0098] The Prepol 1009 used was produced from rapeseed oil in which C18 was dimerized to C36. However, the use of other, especially longer-dimerized, fatty acids is equally possible. In general, any dimerized fatty acid from other sources can be used here.

[0099] Example 2 - Vulcanization of amorphous unsaturated polyester The amorphous unsaturated polyester described above was crosslinked without further processing steps after conventional vulcanization. For this purpose, uncrosslinked rubber (100 parts per 100 units of rubber) was mixed with sulfur (2.75 phr), TBBS (0.8 phr), and zinc oxide (5 phr) at approximately 100°C. This mixture was placed in a mold and vulcanized at 180°C for 1 hour. The resulting material was characterized by DSC and tensile elongation tests. The vulcanized product was insoluble, not molten, and exhibited rubber behavior characteristics equivalent to those of commercially available rubber.

[0100] Figure 1 shows the cyclic stress-strain curve obtained using a tensile elongation test specimen according to ISO 527-2, type 5A. The X-axis represents elongation (%), and the Y-axis represents stress (MPa). The cyclic stress-strain test revealed the elastic, rubber-like properties of the manufactured material.

[0101] Example 3 - Depolymerization of vulcanized products To depolymerize the vulcanized polyester, it was added to approximately 10 times its volume of methanol and stirred in a pressurized reactor at 150°C for 6 days. The resulting homogeneous brown suspension was filtered, the solvent was removed under reduced pressure, and then distilled to separate three fractions. Fraction 1 was a mixture rich in ethylene glycol, obtained at 5 mbar, i.e., 500 Pa, and a temperature of 110–130°C. Fraction 2 consisted mainly of crosslinked and uncrosslinked hexanoic acid monomers, obtained at 0.05 mbar, i.e., 5 Pa, and a temperature of 220°C. Pure dimethyldicarboxylic acid ester was separated from fraction 3 in 98% yield at 0.05 mbar, i.e., 5 Pa, and a temperature of 250–300°C. The separated monomers were confirmed to be of over 99% purity by NMR. The recycled dimethyldimethyl acid ester was successfully utilized for the resynthesis of the amorphous polyester described above.

[0102] Example 4: Biodegradation test in soil at 25°C Amorphous unsaturated polyester was synthesized as described in Example 1 and vulcanized as described in Example 2. 13 14C-labeled ethylene glycol was used. 13The 14C-labeled material was subjected to decomposition tests in agricultural soil in three separate stages at 25°C in the dark, with cellulose as the control. 13 14C-labeled CO2 could be selectively quantified using the apparatus described by TF Nelson (Nelson, TF, Baumgartner, R., Jaggi, M. et al. NatCommun, 2022, 13, 5691).

[0103] Figure 2 shows the Y-axis added 13 The degree of mineralization of carbon C is shown in %, and the test period is shown in days (d) on the X axis. After approximately 90 days, approximately 30% mineralization can be confirmed. Therefore, this material is biologically depolymerizable. 13 Monomers labeled with 1C have been shown to undergo mineralization. Cellulose was treated as a biodegradable reference material under the same conditions and reached a degree of mineralization of 60-75% after 90 days.

[0104] Example 5: Production of hydroxy-terminated mclPHA with a molecular weight of 2000 to 20000 g / mol In a typical decomposition reaction for producing hydroxy-terminated mclPHA with a molecular weight of 2000–20000 g / mol, mcl and / or sclPHA with a molecular weight of 80000 g / mol and a 10% unsaturated side chain ratio was used. The polymer was dissolved in an aprotic solvent such as chloroform, toluene, or xylene at a concentration of 10% w / v and placed in a round-bottom flask. To this solution, ethylene glycol in a 1:1 molar ratio relative to the end groups of the mclPHA and sulfuric acid (0.5–1 mass%) as a catalyst were added. The mixture was heated to 100–120°C with stirring and held at this temperature for 4–6 hours. The progress of the reaction was periodically monitored by molecular weight sampling and analysis by GPC. Alternatively, the reaction was sometimes carried out in a continuous extrusion process to avoid the need for additional solvents.

[0105] When the desired molecular weight of 2000–20000 g / mol was reached, the reaction mixture was cooled to room temperature. The reaction was stopped by adding deionized water or by introducing the extruded product into a water bath, and the acid was diluted. The mixture was neutralized with sodium bicarbonate. The phases were separated using a separation funnel, and the organic phase was washed several times with deionized water to remove residual acid and salts, and dried on anhydrous magnesium sulfate. The solvent was removed, and the hydroxy-terminated mclPHA was separated. The product was dried under vacuum at room temperature to remove residual solvent. The final product was characterized by GPC to confirm that the molecular weight was within the desired range of 2000–20000 g / mol.

[0106] Example 6 - Synthesis of amorphous, unsaturated, vulcanized polyesters using mclPHA In a typical polycondensation reaction for producing amorphous, unsaturated, and therefore vulcanized polyester, the monomers Pripol dimethaneic acid (1 equivalent), hydroxy-terminated mcl-PHA (1 equivalent), and ethylene glycol (2 equivalents) were placed in a round-bottom flask together with the catalyst dibutyltin oxide (DBTO) (0.02 equivalents) and the stabilizer butylhydroxytoluene (BHT) (1% by mass). The mixture was degassed and heated to 140°C with stirring. Excess ethylene glycol and water produced by the condensation reaction were separated by distillation. After 4 hours and 24 hours, a reduced vacuum of 0.05 mbar, i.e., 5 Pa, was gradually applied. At 0.05 mbar, i.e., 5 Pa, and 140°C, the reaction was continued for 2 days until the polymer lost its fluidity due to its high viscosity. The temperature was then raised to 160°C for 4 hours and cooled to room temperature to terminate the reaction. The synthesized polymer was 1 H and 13 Analysis was performed using 1C-NMR, GPC, and DSC. This polyester was a highly viscous, perfectly amorphous material with a glass transition temperature 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. As confirmed by NMR, the double bond in the unsaturated side chain of mclPHA was retained during synthesis.

Claims

1. Rubber mixture containing a polymer component represented by formula (I): [-(O=C)-A-(C=O)-O-B-O-] ｎ (I) In the formula, A is the molecular formula C ｃ H ｄ Includes, In the formula, the exponent c is an integer in the range of 2 to 200, for example, an integer in the range of 2 to 20, and the exponent d is an integer in the range of 2 to 400, for example, an integer in the range of 2 to 40. In the formula, B is the molecular formula C ｅ H ｆ Includes, In the formula, the exponent e is an integer in the range of 2 to 200, for example, an integer in the range of 2 to 20, and the exponent f is an integer in the range of 2 to 400, for example, an integer in the range of 2 to 40. Here, at least one of components A or B does not contain an isolated double bond or a conjugated double bond. At least one of the components A or B contains an isolated or conjugated double bond, The exponent n is an integer in the range of 5 to 50000.

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

3. Further polymer components represented by formula (II) --G-O-[-(O=C)-A-O-(C=O)-B-O]] ｎ -H (-I) and / or further polymer components represented by formula (III) --[-(O=C)-A-O-(C=O)-B-O-] ｎ -+ (--I) The rubber mixture according to claim 1 or 2, comprising: where A has the molecular formula C ｃ H ｄ and contains In the formula, the exponent c is an integer in the range of 2 to 200, for example, an integer in the range of 2 to 20, and the exponent d is an integer in the range of 2 to 400, for example, an integer in the range of 2 to 40. In the formula, B is the molecular formula C ｅ H ｆ Includes, In the formula, the exponent e is an integer in the range of 2 to 200, for example, an integer in the range of 2 to 20, and the exponent f is an integer in the range of 2 to 400, for example, an integer in the range of 2 to 40. Here, at least one of the components A or B does not contain an isolated double bond or a conjugated double bond, and at least one of the components A or B contains an isolated double bond or a conjugated double bond, and the exponent n is an integer in the range of 5 to 50000. In the formula, G is the molecular formula C ｇ H ｈ Includes, In the formula, the exponent is an integer in the range of 2 to 50, and the exponent h is an integer in the range of 4 to 100.

4. The rubber mixture according to claim 3, comprising hydroxy-terminal medium-chain (mcl) polyhydroxyalkanoate (PHA) and / or long-chain (lcl) PHA as constituent blocks of a polymer component represented by general formula (II) and / or general formula (III). --G-O-[-(O=C)-A-O-(C=O)-B-O]] ｎ -H (-I) --[-(O=C)-A-O-(C=O)-B-O-] ｎ -+ (--I)

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

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

7. A rubber mixture according to any one of claims 1 to 6, wherein the glass transition temperature is -150°C to +50°C.

8. Use of the rubber mixture according to any one of claims 1 to 7 for the manufacture of tires, drive belts, toys, seals, dampers, brakes, membranes, valves, clothing, hoses, chewing gum, bags, shoes, mats, adhesives, medical supplies, cosmetics, hygiene products, gloves, and rubber bands.

9. (i) A step of providing a monomer or oligomer constituent block selected from the group consisting of one or more monomers or oligomer constituent blocks of general formula (II) and / or (IV) to (IIX) into a reaction solution, --G-O-[-(O=C)-A-O-(C=O)-B-O]] ｎ -H (-I) RO-(O=C)-D-(C=O)-OR (IV) HO-E-OH (V) RO-[-(O=C)-D-(C=O)-O-E-O-] ｋ -(O=C)-D-(C=O)-OR (VI) _________________________________________ ｌ 、および --[-(O=C)-D-(C=O)-O-E-O-] ｍ -+ (--E), (ii) A step of reacting the reaction solution for a specific period of time under appropriate reaction conditions to carry out a polycondensation reaction of monomer or oligomer constituent blocks to obtain a polymer of general formula (I), (iii) A step of crosslinking a polymer of general formula (I) by adding a photoinitiator and / or vulcanizing agent, for example, a vulcanizing agent containing sulfur, peroxide, or azo initiator. A method for producing the rubber mixture according to any one of claims 1 to 7, including the following:

10. The method according to claim 9, further comprising the step of mixing a polymer of formula (I) with a polymer of formula (III) before or during the step of crosslinking the polymers.

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

12. - Preferably, mcl PHA and / or lcl PHA having a molecular weight of 40,000 to 1,000,000 g / mol, or a molecular weight of 60,000 to 200,000 g / mol, are depolymerized under appropriate reaction conditions in the presence of a diol, such as ethylene glycol, to obtain an unsaturated hydroxy-terminated mcl PHA and / or lcl PHA oligomer constituent block of a polymer component represented by general formula (II) or general formula (III), where this oligomer constituent block has a molecular weight of 2,000 to 20,000 g / mol. - Add the obtained unsaturated hydroxy-terminated mcl PHA and / or lcl PHA oligomer constituent block to the reaction solution as a diol component for polycondensation to the polymer of formula (I). Further including, The method according to any one of claims 9 to 11.

13. A method for producing monomers and / or oligomer units from a vulcanized rubber mixture according to any one of claims 1 to 7, (i) To provide the vulcanized rubber mixture according to any one of claims 1 to 7 in an alcoholic and / or aqueous reaction mixture, (ii) Depolymerizing the vulcanized rubber mixture by heating the reaction mixture at a temperature in the range of 20 to 400°C for a certain period of time. (iii) Separation of monomers and / or oligomer units from the reaction mixture, and Furthermore, (iv) Optionally, purify the separated monomers and / or oligomer units. The method, including the method described above.

14. All or at least part of the monomer and / or oligomer units are general formulas (IV) to (IIX) RO-(O=C)-D-(C=O)-OR (IV) HO-E-OH (V) RO-[-(O=C)-D-(C=O)-O-E-O-] ｋ -(O=C)-D-(C=O)-OR (VI) ________________________________________ ｌ 、および --[-(O=C)-D-(C=O)-O-E-O-] ｍ -+ (--+) Included in the group consisting of, Here, D is the molecular formula C ｗ H ｘ Includes, Here, the exponent w is an integer in the range of 2 to 200, for example, an integer in the range of 2 to 20, and the exponent x is an integer in the range of 2 to 400, for example, an integer in the range of 2 to 40. Here, B is the molecular formula C ｙ H ｚ Includes, Here, the exponent y is an integer in the range of 2 to 200, for example, an integer in the range of 2 to 20, and the exponent z is an integer in the range of 2 to 400, for example, an integer in the range of 2 to 40. Here, R is a hydrogen atom or a C1-C10 alkyl group. Here, the exponents k, l, and m are integers in the range of 1 to 50. The method according to claim 13.

15. All or at least part of the monomer and / or oligomer units are of general formula (IX) and formula (X) RO-(O=C)-F-OH(IX), and RO-[-(O=C)-F-O-] ｐ -H (X) Included in the group consisting of, Here, F is the molecular formula C ｑ H ｒ Includes, The exponent q is an integer in the range of 2 to 200, for example, an integer in the range of 2 to 20, and the exponent r is an integer in the range of 2 to 400, for example, an integer in the range of 2 to 40. Here, R is a hydrogen atom or a C1-C10 alkyl group. The method according to claim 14, wherein the exponent p is an integer in the range of 1 to 50.

16. - Depolymerizing the rubber mixture according to any one of claims 1 to 7 in a reaction step according to any one of claims 13 to 15, which includes a step of purifying the separated monomer and / or oligomer units, and - A rubber mixture according to any one of claims 1 to 7 is manufactured according to a polycondensation method according to any one of claims 9 to 11. including, A method for recycling a rubber mixture as described in any one of claims 1 to 7.

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