This method is used to produce rPET plastic material for use in thin-walled injection molding processes, and hollow materials are manufactured using this method.

Abstract

The invention relates to a method for producing rPET plastic material for use in thin-walled injection molding processes in which the injection molding feedstock, having a viscosity between 0.50 and 0.7 dL / g, is produced with the aid of a chain-breaking compound from recycled used PET with a viscosity between 0.72 and 0.86 dL / g according to ASTM D4603 and a maximum copolymer content of approximately 3%. By this method, the shredded and dried PET material is melted and decontaminated to a degree suitable for applications in the food and consumer goods sector. The chain-breaking compound is added to the rPET material during the melt of the recycled extruder and / or preferably during the melt of the injection molding equipment to reduce viscosity and enrich the PET with copolymer.

Description

[0001] Process for producing an rPET plastic material for use in a thin-wall injection molding process and hollow bodies produced by the thin-wall injection molding process

[0002] Field of the invention

[0003] The present invention relates to a method for producing an rPET plastic material for use in a thin-wall injection molding process according to the preamble of claim 1 and a hollow body produced by the thin-wall injection molding process.

[0004] State of the art

[0005] The standard PET types currently used for bottle production in a stretch blow molding process are predominantly linear PET types (no branched ones) with a low copolymer content of less than 5 wt.% and an intrinsic viscosity (IV) between 0.72 and 0.86 dl / g (according to ASTM D 4603). When PET is processed using the most commonly used one- or two-stage stretch blow molding process (injection stretch blow molding = ISBM), the material typically degrades to a viscosity between 0.01 and 0.09 dl / g, while the copolymer content remains essentially unchanged. Studies have shown that the copolymer content can increase slightly, as even atypical packaging with higher copolymer content sometimes enters the recycling stream and cannot be easily sorted out. In addition, reactions occur in which more diethylene glycol (DEG) is formed and more DEG is incorporated into the polymer chain.

[0006] However, unlike the stretch blow molding process most commonly used for PET bottle production, thin-wall injection molding requires viscosities between 0.5 and 0.7 dl / g. This means that the material generated in the standard PET recycling process, including the regenerated material from it, cannot be used for the injection molding process.

[0007] According to recent legislation, the European packaging industry is required to use up to 35% recycled material in newly manufactured PET articles. This legal requirement applies to both the ISBM and injection molding processes. It would be desirable, in principle, for injection-molded articles made from low-viscosity material to be collected separately so that the recovered material could be reused for the production of injection-molded articles. Unfortunately, this is currently not possible for economic reasons, as economies of scale do not allow for this separate collection and recycling stream for very small quantities.

[0008] However, in the standard PET recycling stream, the low-viscosity injection-molded articles, which are generally only present in small quantities, do not cause problems because the chain lengths are equalized by the "cross esterification" that takes place in the melt. PET for the blow molding process, with a viscosity of 0.72 to 1.4 dl / g according to ASTM D4603, is far too hard and tough to be used to inject complex, thin-walled articles. If one wishes to inject injection-molded articles at a typical pressure of up to 3000 bar, standard PET cannot be used with a wall thickness (L) to flow path (D) ratio of 1 to 100 to 1 to 350 (thin-wall injection molding up to 1 to 500), which is typical for injection molding, because then large parts of the mold could not be filled.

[0009] PET materials are known as virgin materials with a viscosity of 0.5 to 0.7 dl / g (ASTM D4603), which is designed precisely for these applications. However, there is no separate recycling stream specifically for these polyester types. Packaging manufacturers who wish to use this material will still have to demonstrate a recycling content of 25% to 50% in the future, depending on which legal regulation or voluntary commitment is binding for the distributor by 2025 or 2030. However, a much higher recycling content of 40 to 100% is usually required for polyester applications.

[0010] For injection-molded packaging, a PET recycling material with a viscosity of 0.5 to 0.7 dl / g is required. This sounds quite simple at first, as PET can be easily broken down to the desired viscosity using water and heat.

[0011] If 100 to 1000 ppm of water is added to the most commonly used PET recycling material during PET injection molding, the PET will degrade exactly as planned to a viscosity of 0.5 to 0.7 dl / g, but this degradation (hydrolysis) will cause the material to become whitish and cloudy and semi-crystalline. Bubbles may also form. Uncontrolled crystallization results in sink marks, blowholes, and severely distorted parts, which, due to their low viscosity and high residual stress, are far too brittle for their final use as packaging.

[0012] The main PET recycling stream available on the market consists primarily of PET bottles produced from a material with a viscosity of approximately 0.72 to 0.86 dl / g in a stretch blow molding process (ISBM process). This recycling stream's viscosity is too high for injection molding thin-walled parts. The recycled material from the main stream available on the market primarily contains PET ISBM bottles with a copolymer content of 2 to 3%. This copolymer content varies greatly depending on whether the recycled material contains a large amount of film and thermoformed articles, PET-G, or reusable bottles. In general, the copolymer content is too unstable to produce stable, thin-walled injection molded parts from rPET that are not subject to uncontrolled crystallization.

[0013] Due to other components in the recycling stream, such as thermoforming film, and the degradation of PET during processing, the average viscosity of the recycled product is 0.02 to 0.09 dl / g lower than the original material. However, to be suitable for food contact, it must be decontaminated using heat and vacuum (or nitrogen). This decontamination can take place in a dryer before the recycling extruder, in the recycling extruder, or after the recycling extruder in a so-called SSP process. Combinations are also common.

[0014] During decontamination, not only is the gas removed, but the polyester fabric inevitably rebuilds under these conditions and the chains become longer.

[0015] Even though some highly degraded PET is available on the market, which would be suitable in terms of viscosity, its composition and contamination are unsuitable for the production of thin-walled PET injection-molded packaging. This is because it has not been decontaminated using a vacuum and, in addition, crystallizes too quickly.

[0016] It is known that PET can be specifically degraded by adding monoethylene glycol (glycolysis). WO0001997020886A1, for example, discloses a process that recycles previously used polyester materials by means of glycolysis and subsequent purification. Recycled PET is contacted with 1.1 to 10 mol of ethylene glycol per mol of dicarboxylic acid in the polyester at a temperature in the range of 150 to 300 °C for between 10 minutes and 4 hours to depolymerize the polyester and produce a reaction mixture containing monomeric and oligomeric dihydroxy species. Excess ethylene glycol is then removed, and the reaction mixture is dissolved in a hot solvent. The hot solution is then filtered to remove unwanted impurities. The solution is then cooled, and the dihydroxy species precipitate as a solid.

[0017] It is also known that PET undergoes cross- and trans-esterification through the addition of low-molecular-weight esters or polyesters, and that the viscosity adjusts under heat by exchanging polyesters in the chain. Thus, a polyester with monomers A and B and a second polyester with monomers B and C can be transesterified to produce a third copolyester containing monomers of types A, B, and C in its chains. This is known for PET polyesters with isophthalic acid (IPA) and diethylene glycol (DEG), but also for PET copolyesters with naphthalenedicarboxylic acid (NDC) and furandicarboxylic acid (FDCA).

[0018] Task

[0019] The object of the present invention is to provide an rPET material which is particularly suitable for thin-wall injection molding and which originates primarily from rPET obtained from the collection of post-consumer PET articles, in particular from bias-molded PET bottles. A further aim is to propose an rPET material which can be injection-molded at 500 to 3000 bar, ideally at approximately 1000 bar, with a wall thickness to flow path ratio typical for injection molding of 1:100 to 1:350 or up to 1:500 for thin-wall injection molding. In particular, it is an aim that the proposed material crystallizes only slowly. A further aim is that the material can be processed in such a way that it remains transparent, i.e. essentially crystal clear, and that no crystallization of the material scatters the light to such an extent that the contents are no longer visible.

[0020] Definitions:

[0021] In the context of the present invention, the term "viscosity" is understood to mean the intrinsic viscosity (IV) measured according to ASTM 4603-03 standard.

[0022] For the purposes of the present invention, "pure PET" means that PET has been sorted within the scope of current technological possibilities, so that the weight proportion of non-pure plastic is less than 2%, preferably less than 1%, and particularly preferably less than 0.5%. rPET is used herein as an abbreviation for recycled post-consumer PET.

[0023] "Bottle Grade PET Post-consumer Recycling Flake" is rPET processed into flakes which comes from the collection of post-consumer PET articles, in particular PET bottles

[0024] In the context of the present invention, ISBM-PET is understood to mean PET (including PET copolymers) that is suitable for use in an ISBM process, ie has an IV between 0.72 dl / g and 0.86 dl / g (viscosity measurement according to ASTM D4603).

[0025] In the context of the present invention, "chain breakers" are understood to mean chemical compounds that are suitable for degrading PET or for being incorporated into the polymer chain as a copolymer.

[0026] Description

[0027] The invention relates to a process for producing an rPET plastic material for use in a thin-wall injection molding process with a ratio of wall thickness (L) to flow path (D) of 1 to 100 to 1 to 350, which process comprises the following steps: a) sorting, washing and comminuting post-consumer PET articles, ie PET bottles produced predominantly using the ISBM process, the PET material of which has an intrinsic viscosity of between 0.72 and 0.86 dl / g according to ASTM D4603, b) removing contaminants such as metal or paper before, simultaneously with or after process step a), c) subsequently drying the comminuted PET material, d) melting the comminuted and dried PET material and preferably decontamination thereof in a degassing or degassing process. Recycling extruder and subsequent granulation, and e) production of a thin-walled injection-molded article from the PET material in an injection molding process.

[0028] According to the invention, the object is achieved in a method according to the preamble of claim 1 in that a chain breaker is added to the granulated material and the melt of granulate and chain breaker is reactively extruded and injected directly into an injection mold, wherein the process is carried out in such a way that the intrinsic viscosity of the injection-molded article is reduced during extrusion to 0.5 to 0.7 dl / g and preferably to 0.5 to 0.65 dl / g and a thin-walled injection-molded article can be produced in an injection molding process in which the ratio of wall thickness (L) of the injection-molded article to the flow path (D) is from 1 to 100 to 1 to 350 or up to 1 to 500 in the case of thin-wall injection molding. This process has the advantage that rPET from a common PET recycling stream, especially from bias-molded PET bottles, can also be used for the production of thin-walled injection-molded articles.

[0029] Advantageously, the extrusion temperature, the residence time of the material in the extruder and the amount of Chain Breaker are selected so that the extruded material has an intrinsic viscosity (IV) greater than 0.5 dl / g, in particular between 0.52 and 0.68 dl / g and preferably between 0.55 and 0.65 dl / g. Such material can be easily processed into thin-walled, strip-free

[0030] Process articles.

[0031] Preferably, a PET bottle stream is used that contains particularly low levels of contamination from polymers other than PET (e.g., PA blends). Within the context of the present invention, "particularly low" means that the proportion of PA blends, radical scavengers, and other additives such as oxygen scavengers, acetaldehyde scavengers, UV absorbers, slip additives, infrared absorbers, etc. is less than 10 wt.%, preferably less than 5 wt.%, and particularly preferably less than 3 wt.%.

[0032] According to one process variant, either a specific amount of monoethylene glycol or a specific amount of water is used as a chain breaker. Surprisingly, with the help of monoethylene glycol or water, the IV can be reduced by splitting the PET molecules directly during the injection molding process, allowing thin-walled articles to be produced.

[0033] Preferably, PET recycling material with a water content between 100 and 1000 ppm, and preferably between 300 and 1000 ppm, is used for extrusion. This means that the preceding drying and decontamination is preferably carried out to achieve the desired water content. Alternatively, the PET recycling material can be re-enriched with water after drying and / or decontamination (process steps c) and / or d)).

[0034] Instead of water, between 50 and 1000 ppm of monoethylene glycol can be added or dosed into the granulated material. This also leads to the desired reduction of the intrinsic viscosity during the injection process.

[0035] According to another preferred process variant, compounds are used as chain breakers, which can be incorporated into the PET polymer molecules, thus leading to a higher copolymer content. Surprisingly, by increasing the copolymer content, the intrinsic viscosity can be reduced and the crystallization rate slowed to such an extent that thin-walled, transparent, and stripe-free articles can be injected. This effect was unexpected, as it was expected that the material would become cloudy. Furthermore, it was expected that bubbles and small cracks would form in the injection-molded article, similar to the process that occurs when water is used to degrade the rPET.By adding suitable chain breakers and incorporating them into the PET polymer chains, the copolymer content can be increased during extrusion by at least 1%, preferably at least 2%, and particularly preferably by at least 3%, as desired, and the viscosity of the material can be reduced. The proposed process exploits the fact that higher copolymer contents alter the PET molecular chain in such a way that crystallization is inhibited or suppressed.

[0036] Monoethylene glycol is known as a chain breaker. However, monoethylene glycol is already a component of the PET chain. Adding monoethylene glycol breaks the chain but does not increase the copolymer content.

[0037] Diols, which can be incorporated into the chain as copolymers, are advantageously used as chain breakers. Preferred diols are diethylene glycol, propylene glycol, and / or butylene glycol, but also cyclic polyols such as 3,9-bis(l,l-dimethyl-2-hydroxyethyl)-2,4,8,10-tetraoxaspiro[5.5]undecane (spirol glycol).

[0038] Another process variant uses dicarboxylic acids as chain breakers. These are also very suitable for reducing chain lengths.

[0039] Preferred dicarboxylic acids as chain breakers are isophthalic acid, 2,5-furandicarboxylic acid and / or

[0040] Naphthalenedicarboxylic acid, as it can be incorporated into the polymer chain as a copolymer. According to an advantageous process variant, diesters are used as chain breakers.

[0041] Suitable diesters are, for example, dimethyl isophthalate and / or bis(hydroxyethyl)isophthalate.

[0042] The diols, dicarboxylic acids, diesters can be used individually or as mixtures.

[0043] PET copolymer chains with 2 to 20 monomers containing isophthalic acid (IPA), furandicarboxylic acid (FDCA), naphthalenedicarboxylic acid or diethylene glycol are advantageously used as chain breakers.

[0044] The proportion of isophthalic acid (IPA), furandicarboxylic acid (FDCA), naphthalenedicarboxylic acid or diethylene glycol is advantageously between 3 and 10 wt.%.

[0045] It is also conceivable to use compounds containing an alcohol group and a dicarboxylic acid or an ester group as chain breakers. Examples of such compounds are hydroxyethanoic acid (hydroxyacetic acid), hydroxypropanoic acid, and hydroxybutanoic acid.

[0046] It's also conceivable that caffeine is used as a chain breaker. Caffeine is the common name for 1,3,7-trimethyl-2,6-purindione (short for 1,3,7-trimethylxanthine).

[0047] Advantageously, the chain breakers are added in process step f) before or during melting of the granulate.

[0048] Advantageously, the post-consumer PET material used before drying and recycling process step d) has a copolymer content of a maximum of approximately 3% and preferably a copolymer content of a maximum of 2.5%.

[0049] Process step f) is preferably carried out such that the total copolymer content in the rPET is increased to 2.5 to 8%, preferably to 3.0 to 8%, and particularly preferably to 3.5 to 8%. An increased copolymer content leads to a reduction in the IV and simultaneously a slowing of the crystallization rate, which makes the injection molding of thin-walled articles possible.

[0050] Advantageously, decontamination of the post-consumer incoming goods is carried out by degassing the volatile contaminants at an elevated temperature between 70° and 330°C, preferably between 180 and 220°C before the recycling extruder, ie process step d), and / or in the recycling extruder and / or after the recycling extruder, by means of a vacuum of less than 0.2 bar absolute, or

[0051] Nitrogen purging is carried out for between 0.1 sec and 20 hours, preferably for 4 to 10 hours. After extrusion in the recycling extruder, the granules can optionally be degassed in an SSP reactor at a temperature of 180 to 220°C and for 1 to 15 hours, preferably 4 to 10 hours, under vacuum. Polymerization (polycondensation) takes place simultaneously.

[0052] Decontamination using heat and vacuum can be performed in the extruder and the downstream SSP reactor. Of course, nitrogen can also be used instead of vacuum to remove contaminants. Heat and vacuum or a protective gas atmosphere (e.g., nitrogen) can generally be used during material preparation before the recycling extruder.

[0053] Preferably, the material is decontaminated by a subsequent treatment in the SSP reactor, but the viscosity is not increased so high that it can be turned into a PET that is well suited for the stretch blow molding process, but rather leaves the SSP with a viscosity of < 0.72 dl / g.

[0054] Preferably, the material is decontaminated before the actual injection molding process step f) to such an extent that it is suitable for applications in the food and / or consumer goods sector.

[0055] It is advantageous to produce a masterbatch from the chain breaker, which is then metered directly into the injection molding machine's inlet. This has the advantage that the chain breaker content can be easily controlled and ensures thorough mixing in the extruder.

[0056] Preferably, the shredded PET recycling material is dried after the washing process at temperatures between 60 and 180°C for 1 to 8 hours.

[0057] Advantageously, the intrinsic viscosity of the material used is reduced by 0.05 to 0.3 dl / g, preferably 0.1 to 0.25 dl / g, through the reactive extrusion in process step f).

[0058] Advantageously, the crystallization fraction of the treated rPET injection-molded part is reduced by at least 10% compared to the untreated material without increased copolymer content.

[0059] According to a preferred process variant, the temperature during extrusion and the amount of Chain Breaker are selected so that the extruded material has an IV greater than 0.5 dl / g and in particular between 0.5 and 0.7 dl / g.

[0060] Advantageously, between 0.05 wt.% and 2.8 wt.%, preferably between 0.1 wt.% and 1.0

[0061] % by weight, and particularly preferably between 0.1 and 0.6 wt. %, of chain breaker is added to the PET from process step f). The residence time of the polyester material in the injection molding unit or recycling extruder is advantageously between 20 and 400 s / h, preferably between 30 and 300 s / h, and particularly preferably between 40 and 200 s / h. With the aforementioned residence times, the IV of the polyester material in the presence of a chain breaker can be reduced by 0.05 to 0.3 dl / g during extrusion.

[0062] According to a further embodiment of the invention, the extruded melt is filtered before granulation.

[0063] According to a further embodiment of the invention, the extruded melt is pressed through a perforated filter with a hole size between 30 pm and 300 pm, and preferably between approximately 50 pm and 100 pm. This ensures that the melt has sufficient purity, and turbidity and impurities can be prevented in the final injection-molded product.

[0064] According to a further embodiment of the invention, the rPET material is degassed and decontaminated during extrusion in process step d)

[0065] According to another variant, the melt is divided into thin layers or strands in the extruder. This increases the surface area of ​​the material and allows for very rapid decontamination.

[0066] According to a further embodiment of the invention, the extrusion takes place in a vacuum or in a protective gas atmosphere, in particular under nitrogen.

[0067] A further embodiment of the process involves an alternative form of injection molding or a mixed form of injection molding in the sense of compression molding.

[0068] A further embodiment of the process involves an alternative form of injection molding or a mixed form of injection molding in the sense of spray foaming.

[0069] Description of the procedure:

[0070] Post-consumer PET material which has a viscosity of between approximately 0.7 and approximately 0.86 dl / g is used for the process. Preferably, a PET bottle stream is used which contains particularly little contamination from polymers other than PET (e.g. PA blends). In the context of the present invention, particularly low is understood to mean that the proportion of PA blends, radical scavengers and other additives such as oxygen scavengers, acetaldehyde scavengers, UV absorbers, slip additives, infrared absorbers, etc. is less than 10 wt.%, preferably less than 5 wt.%, and particularly preferably less than 3 wt.%. In a first process step, post-consumer PET bottles are sorted by type, washed, cut and contaminants such as metal, paper, etc. are removed. During sorting, the collected PET material is first sorted by color and then foreign plastics are preferably sorted out.

[0071] In a second process step, the cut PET flakes are dried.

[0072] In a third process step, the rPET is decontaminated and granulated in a degassing or recycling extruder.

[0073] In a fourth process step, a chain breaker is added to the granules, and then the granules are subjected to reactive extrusion. Under these conditions, the rPET is rapidly degraded during extrusion in the injection unit, meaning the average molecular weight of the rPET and thus its intrinsic viscosity decreases.

[0074] The addition of the Chain Breaker is primarily intended for the injection molding unit, but can be added concurrently or, in rare cases, alternatively in the recycling extruder. By adding the Chain Breaker not only in the extruder of the injection molding machine, but also in the extruder of the recycling machine, the recycled material can be specifically broken down during the extrusion process and enriched with copolymers.

[0075] Examples of implementation:

[0076] Example 1:

[0077] Regrind from post-consumer PET bottles with an average IV of 0.72 dl / g and an average copolymer content of 1% isphthalic acid and 1.3% diethylene glycol are mixed with 0.5% diethylene glycol in the recycling extruder and extruded at an average temperature of 290°C.

[0078] Surprisingly, the viscosity after recycling in the extruder decreased much more than usual, to a value of only 0.58 dl / g. A subsequent SSP (6h at 220°C to achieve food contact compliance) reduced the granules to only 0.72 dl / g. These granules are dried to below 50 ppm water content and added to an injection molding machine along with a second amount of diethylene glycol (0.2%). Surprisingly, the PET was able to decrease again to a viscosity of only 0.55 dl / g, and a preform with a wall thickness of only 1 mm and a flow path of 120 mm could be injected.

[0079] Example 2:

[0080] Ground material from post-consumer bottles is processed in a standard recycling process into granules for the stretch blow molding process with a viscosity in an SSP of 0.76 dl / g. The dried granules (180°C - 6h, dried air, 2m 2However, the PET preform (at a temperature of -35°C (air / kg PET dew point -35°C)) is fed into an injection molding machine and mixed with 2% diethylene glycol. In the melt, the diethylene glycol degraded the PET to a viscosity of 0.61 dl / g, and surprisingly, a preform with a wall thickness of only 1 mm and a flow path of 120 mm could be molded.

[0081] The invention provides a process by which previously used polyester materials, including either production waste polyester materials and / or used polyester materials, can be conveniently and efficiently recovered and purified. The collected PET material is first color-sorted, preferably re-sorted, cut into small pieces (ground), washed, dried, extruded, and preferably simultaneously decontaminated, granulated, and optionally built up and decontaminated again, and then extruded into a thin-walled article in the presence of chain breakers.

[0082] The invention relates to a process in which a starting material for injection molding with a viscosity between 0.50 and 0.7 dl / g is produced from recycled post-consumer PET with a viscosity between 0.72 and 0.86 dl / g according to ASTM D4603 and a maximum copolymer content of approximately 3 wt.% using a chain breaker. During the process, the shredded and dried PET material is melted and decontaminated to such an extent that it is suitable for applications in the food and consumer goods sectors. A chain breaker is added to the rPET material in the melt of the recycling extruder and / or preferably in the melt of the injection unit in order to reduce the viscosity and enrich the PET with copolymers.

Claims

Patent claims 1. A process for producing an rPET plastic material for use in a thin-wall injection molding process with a wall thickness (L) to flow path (D) ratio of 1:100 to 1:350 or up to 1:500 in thin-wall injection molding, in which process a) post-consumer PET articles, mostly PET bottles produced using the ISBM process, whose PET material has an intrinsic viscosity between 0.72 and 0.86 dl / g according to ASTM D4603, are sorted, washed, and crushed, b) contaminants such as metal or paper are removed before, simultaneously with, or after process step a), c) the crushed PET material is subsequently dried, d) the crushed and dried PET material is then melted and preferably in a degassing or...a recycling extruder is decontaminated and subsequently granulated, and e) a thin-walled injection-molded article is produced from the PET material in an injection molding process, characterized in that f) in process step e) a chain breaker is added to the granulated material and the melt of granules and chain breaker is reactively extruded and injected directly into an injection mold, wherein the process is carried out in such a way that the intrinsic viscosity of the injection-molded article is reduced to 0.5 to 0.7 dl / g and preferably to 0.5 to 0.65 dl / g during extrusion and a thin-walled injection-molded article can be produced in an injection molding process in which the ratio of wall thickness (L) of the injection-molded article to flow path (D) is from 1 to 100 to 1 to 350.

2. Method according to claim 1, characterized in that the temperature during extrusion, the residence time of the material in the extruder and the amount of chain breaker are selected such that the extruded material has an intrinsic viscosity (IV) greater than 0.5 dl / g, in particular between 0.52 and 0.68 dl / g and preferably between 0.55 and 0.65 dl / g.

3. Method according to claim 1 or 2, characterized in that either a certain amount of monoethylene glycol or a certain amount of water is used as the chain breaker.

4. Method according to one of claims 1 to 3, characterized in that the PET recycling material used for extrusion contains 100 to 1000 ppm water.

5. Method according to one of claims 1 to 3, characterized in that between 50 and 1000 ppm monoethylene glycol is added to the granulated material. A process according to any one of claims 1 to 5, characterized in that compounds are used as chain breakers which can be incorporated into the PET polymer molecules and thus lead to a higher copolymer content. A process according to claim 6, characterized in that the copolymer content is increased by at least 1%, preferably by at least 2%, and particularly preferably by at least 3%, compared to the PET starting material. A process according to claim 6 or 7, characterized in that diols are used as chain breakers. A process according to claim 8, characterized in that diethylene glycol, propylene glycol, butylene glycol, and / or cyclic polyalcohols are used as diols. A process according to claim 6 or 7, characterized in that dicarboxylic acids are used as chain breakers. A process according to claim 10, characterized in that isophthalic acid, 2,5-furandicarboxylic acid, and / or naphthalenedicarboxylic acid are used as dicarboxylic acids.A process according to claim 6 or 7, characterized in that diesters are used as chain breakers. A process according to claim 12, characterized in that dimethyl isophthalate and / or bis(hydroxyethyl) isophthalate are used as diesters. A process according to claim 6 or 7, characterized in that PET copolymer chains with 2 to 20 monomers containing isophthalic acid (IPA), furandicarboxylic acid (FDCA), naphthalenedicarboxylic acid, or diethylene glycol are used as chain breakers. A process according to claim 14, characterized in that the proportion of isophthalic acid (IPA), furandicarboxylic acid (FDCA), naphthalenedicarboxylic acid, or diethylene glycol is between 3 and 10 wt.%. The method according to claim 6 or 7, characterized in that compounds are used as chain breakers which have an alcohol group and a dicarboxylic acid or an ester group, such as hydroxyethanoic acid, hydroxypropanoic acid, hydroxybutanoic acid, etc. 15).A method according to claim 6 or 7, characterized in that caffeine is used as a chain breaker. A method according to any one of claims 1 to 17, characterized in that the addition of the chain breaker in process step f) takes place before or during melting. A method according to any one of claims 1 to 18, characterized in that the post-consumer PET material used undergoes a chain breaker before drying and recycling in process step d). The copolymer content is a maximum of approximately 3% and preferably a maximum of 2.5%. A process according to any one of claims 1 to 19, characterized in that process step f) is carried out such that the total copolymer content in the rPET is increased to 2.5% to 8%, preferably to 3.0% to 8%, and particularly preferably to 3.5% to 8%. A process according to any one of claims 1 to 20, characterized in that the post-consumer input material is decontamination by degassing the volatile contaminants at an elevated temperature between 70°C and 330°C, preferably between 180°C and 220°C, before the recycling extruder (i.e., process step d) and / or in the recycling extruder and / or after the recycling extruder, by means of a vacuum of less than 0.2 bar absolute or nitrogen purging for between 0.1 seconds and 20 hours, preferably for 4 to 10 hours.A method according to any one of claims 1 to 21, characterized in that the material is decontaminated prior to the actual injection molding process step f) to such an extent that it is suitable for applications in the food and / or consumer goods sector. A method according to any one of claims 1 to 22, characterized in that a masterbatch is produced using material from process step d) and a chain breaker, and this masterbatch is metered directly into the feed of the injection molding machine. A method according to any one of claims 1 to 23, characterized in that in process step c) the comminuted PET material is dried at temperatures between 60 and 180°C, preferably for 1 to 8 hours. A method according to any one of claims 1 to 24, characterized in that the viscosity of the material used is reduced by 0.05 to 0.3 dl / g, preferably by 0.1 to 0.25 dl / g, by the reactive extrusion in process step f).A method according to any one of claims 1 to 25, characterized in that the crystallization fraction of the treated rPET injection-molded part is reduced by at least 10% compared to the untreated material without an increased copolymer content. A method according to any one of claims 1 to 26, characterized in that the extrusion temperature and the amount of chain breaker are selected such that the extruded material or the material of the manufactured injection-molded article has an IV greater than 0.5 dl / g and, in particular, between 0.5 and 0.7 dl / g. A method according to any one of claims 6 to 27, characterized in that between 0.05 wt.% and 2.8 wt.%, preferably between 0.1 wt.% and 1.0 wt.%, and particularly preferably between 0.1 wt.% and 0.6 wt.%, of chain breaker is added to the PET of process step f). A method according to any one of claims 1 to 28, characterized in that the extruded melt is filtered before granulation. A method according to any one of claims 1 to 29, characterized in that the extruded melt is pressed through a perforated filter with a hole size between 30 pm and 300 pm, and preferably between approximately 50 pm and 100 pm. A method according to any one of claims 1 to 30, characterized in that the material is degassed during extrusion in process step d). A method according to any one of claims 1 to 31, characterized in that the melt is divided into thin layers or strands in the extruder. A method according to any one of claims 1 to 32, characterized in that the extrusion in process step f) takes place in a vacuum or in a protective gas atmosphere, in particular under nitrogen.A method according to any one of claims 1 to 33, characterized in that a specific amount of chain breaker is added to the material in process step d). A method according to any one of claims 1 to 34, characterized in that the residence time of the polyester material in the injection molding unit or recycling extruder is between 20 and 400 see, preferably between 30 and 300 see, and particularly preferably between 40 and 200 see. A method according to any one of claims 1 to 35, characterized in that post-consumer PET material is used which has a viscosity between about 0.7 and about 0.86 dl / g. A method according to any one of claims 1 to 36, characterized in that the method is an alternative form of injection molding or a hybrid form of injection molding in the sense of compression molding or injection foaming. Hollow bodies obtainable according to a method according to any one of claims 1 to 37.