Removal of odorous substances from post-consumer polyolefin wastes.

Abstract

A process for treating recycled polyolefins with an emulsion comprising an aqueous phase and an organic phase, and use of said process and / or emulsion for at least partially removing volatile organic compounds.

Description

[Technical field]

[0001] The present invention relates to a process for treating recycled polyolefins with an emulsion comprising an aqueous phase and an organic phase, and to the use of said process and / or emulsion for at least partially removing volatile organic compounds. [Background technology]

[0002] During the last decade, there has been growing concern about the environmental sustainability of plastics and their use at the current levels. This has led to the creation of new legislation regarding the disposal, collection and recycling of polyolefins. In addition, efforts are being made in many countries to increase the proportion of plastic material that is recycled instead of being sent to landfills.

[0003] In Europe, plastic waste accounts for around 27 million tons of waste each year. Of this amount in 2016, 7.4 million tons were disposed of in landfills, 11.27 million tons were burned (to generate energy) and around 8.5 million tons were recycled. Polypropylene-based materials are particularly problematic as these materials are widely used in packaging. Considering the large amount of waste collected compared to the amount of waste recycled in the above streams (which amounts to only around 30%), there is still a large potential for the intelligent reuse of plastic waste streams and for the mechanical recycling of plastic waste.

[0004] Take the automotive industry as an example. In Europe, there is an End of Life Vehicle (ELV) directive from the EU states that 85% / 95% of the material from the vehicle should be recyclable or recoverable. The current rate of recycling of automotive parts is significantly below this target. On average, a vehicle is composed of 9% plastic by weight, and only 3% of this 9% by weight is currently recycled. Therefore, there is still a need to be met if the target for recycling plastics in the automotive industry is to be achieved. The present invention focuses in particular on waste streams that are mechanically recycled, as opposed to "energy recycling", where polyolefins are burned and used for energy. However, for cost reasons, waste streams with low mechanical and processable properties containing crosslinked polyolefins are often used for energy recovery (e.g. incineration in district heating plants or for heat generation in the cement industry) and are less frequently recycled into new products.

[0005] One major trend in the field of polyolefins is the use of recycled materials from a wide variety of sources. Durable goods streams, such as those derived from waste electrical equipment (WEE) or end-of-life vehicles (ELV), contain a wide variety of plastics. These materials can be processed to recover plastics such as acrylonitrile-butadiene-styrene (ABS), high impact polystyrene (HIPS), polypropylene (PP) and polyethylene (PE). Separation can be performed using density separation in water, followed by further separation based on fluorescence, near infrared absorption or Raman fluorescence. However, it is generally very difficult to obtain either pure recycled polypropylene or pure recycled polyethylene. Generally, the amount of polypropylene recovered on the market is a mixture of both polypropylene (PP) and polyethylene (PE), and this is especially true for post-consumer waste streams. Commercial recyclates from post-consumer waste sources are generally found to contain a mixture of PP and PE, with minor components amounting to less than 50% by weight.

[0006] The better the quality of the recycled polyolefin, i.e., the higher the purity, the more expensive the material. Moreover, recycled polyolefin materials are often cross-contaminated with non-polyolefin materials, such as polyethylene terephthalate, polyamide, polystyrene, or non-polymeric substances, such as wood, paper, glass, or aluminum. In addition, materials high in recycled polypropylene usually have properties much worse than those of virgin materials, unless very small amounts of recycled polyolefin are added to the final formulation. For example, such materials often have poor odor and taste performance, limited stiffness, limited impact strength, poor mechanical properties (e.g., brittleness, etc.), and therefore do not meet customer requirements. The poor mechanical properties can be improved by blending recycled polyolefins with virgin polymers or by the use of reinforcing fillers, however this does not address the odor / taste issue.

[0007] An established method for removing volatile organic compounds from both virgin and recycled polymers involves aeration of the polymer, which may be accomplished by the use of air, inert gases or steam, among others.

[0008] Variations of this process have been known for many years and are described inter alia in EP 0004601 A1, EP 0859809 A1, EP 0964877 A1, EP 1542777 A2 and EP 3647328 A1.

[0009] Although these methods can be very efficient at removing a wide range of volatile compounds, they can also be energy intensive, which may not produce the desired results if the goal is to have a recycling process that is as environmentally friendly as possible.

[0010] Thus, there remains a need for additional methods for reducing odorous and volatile compounds from recycled polyolefin compositions.

[0011] The present invention is based on the finding that treatment of recycled polyolefins with an emulsion (E) comprising an aqueous phase having a pH in the range of 7.0 to 14.0 and an organic phase containing at least 90% v / v of one or more fully saturated organic solvents having a logP value in the range of 1.0 to 10.0 is effective for removing both hydrophilic and hydrophobic volatile organic compounds. [Prior art documents] [Patent documents]

[0012] [Patent Document 1] European Patent Application Publication No. 0004601A1 [Patent Document 2] European Patent Application Publication No. 0859809A1 [Patent Document 3] European Patent Application Publication No. 0964877A1 [Patent Document 4] European Patent Application Publication No. 1542777A2 [Patent Document 5] European Patent Application Publication No. 3647328A1 Summary of the Invention [Means for solving the problem]

[0013] The present invention relates to a method for processing recycled polyolefins comprising, in the order listed, a) providing a recycled polyolefin containing volatile organic compounds; b) The recycled polyolefin i) an aqueous phase having a pH in the range of 7.0 to 14.0; and ii) an organic phase containing at least 90% v / v of one or more fully saturated organic solvents having a logP value in the range of 1.0 to 10.0; and contacting the emulsion (E) with the emulsion (E) comprising: c) removing the aqueous and organic phases from the recycled polyolefin; d) optionally recycling one or both of the aqueous and organic phases; The present invention is directed to a method comprising the steps of:

[0014] In another aspect, the present invention is directed to the use of the process of the present invention for at least partially removing volatile organic compounds from recycled polyolefins.

[0015] In another aspect, the present invention provides a process for at least partially removing volatile organic compounds from recycled polyolefins, comprising: i) an aqueous phase having a pH in the range of 7.0 to 14.0; ii) an organic phase comprising at least 90% v / v of one or more fully saturated organic solvents having a logP value in the range of 1.0 to 10.0; The present invention is directed to the use of an emulsion (E) comprising

[0016] definition In the context of the present invention, the term "volatile organic compound" refers to any organic compound that has an initial boiling point of less than or equal to 250° C., a definition established by the European Union in the VOC Solvents Emissions Directive 1999 / 13 / EC.

[0017] The term "hydrophilic" in the present invention is taken to mean having a partition function between octanol and water (logP(octanol / water)) of less than or equal to 2.0.

[0018] The term "hydrophobic" in the present invention is taken to mean having a partition function between octanol and water (logP(octanol / water)) greater than 2.0.

[0019] The term logP refers to the partition function between two solvents, which unless otherwise stated are taken to be octanol and water. The logP of a given compound is calculated according to the following formula:

number

[0020] The term "fully saturated" means that a compound (typically an organic compound) has no double or triple bonds, i.e., all bonds present in the molecule are single (sigma) bonds. Fully saturated compounds may be linear, branched, or cyclic. Fully saturated compounds are typically less reactive than unsaturated compounds due to the fewer reactive functional groups present in the compound.

[0021] Those skilled in the art will recognize that pH values ​​above 14.0 and below 0.0 are theoretically possible. However, those skilled in the art will also recognize that determining such pH values ​​is very difficult using conventional pH probes. Thus, in the context of the present invention, an aqueous solution having an effective pH above 14.0 is interpreted as having a pH of 14.0, and an aqueous solution having an effective pH below 0.0 is interpreted as having a pH of 0.0.

[0022] In the context of the present invention, the term "rinsing" is used to indicate the addition of a solvent, typically water, used to remove foreign matter or residual liquid from the surface of the polyolefin. This can be accomplished in a very short time, i.e., less than 5 minutes, often less than 1 minute, in contrast to the "washing" process, which typically requires longer times and agitation to extract volatile organic compounds from the polyolefin.

[0023] When the term "comprising" is used in the present specification and claims, it does not exclude other unspecified elements of functional importance or other unspecified elements of minor functional importance. For the purposes of the present invention, the term "consisting of" is considered to be a preferred embodiment of the term "comprising of". In the following, when a group is defined as comprising at least a certain number of elements, this should also be understood to disclose a group that preferably consists only of these elements.

[0024] The unit %v / v refers to the volumetric concentration of a particular solvent in a mixture, i.e., the volume of one component of the mixture divided by the volume of the whole mixture.

[0025] Where an indefinite or definite article such as "a", "an" or "the" is used when referring to a singular noun, this includes a plural of that noun, unless something else is specifically stated. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0026] process The process for treating recycled polyolefins according to the present invention comprises, in the order given, a) providing a recycled polyolefin containing volatile organic compounds; b) The recycled polyolefin i) an aqueous phase having a pH in the range of 7.0 to 14.0; and ii) an organic phase containing at least 90% v / v of one or more fully saturated organic solvents having a logP value in the range of 1.0 to 10.0; and contacting the emulsion (E) with the emulsion (E) comprising: c) removing the aqueous and organic phases from the recycled polyolefin; d) optionally recycling one or both of the aqueous and organic phases; Includes.

[0027] Step (d) is an optional step, which means that the process of the present invention comprises, in the order given, a) providing a recycled polyolefin containing volatile organic compounds; b) The recycled polyolefin i) an aqueous phase having a pH in the range of 7.0 to 14.0; and ii) an organic phase containing at least 90% v / v of one or more fully saturated organic solvents having a logP value in the range of 1.0 to 10.0; and contacting the emulsion (E) with the emulsion (E) comprising: c) removing the aqueous and organic phases from the recycled polyolefin; This means that it may include

[0028] Alternatively, the process of the present invention comprises, in the order given, a) providing a recycled polyolefin containing volatile organic compounds; b) The recycled polyolefin i) an aqueous phase having a pH in the range of 7.0 to 14.0; and ii) an organic phase containing at least 90% v / v of one or more fully saturated organic solvents having a logP value in the range of 1.0 to 10.0; and contacting the emulsion (E) with the emulsion (E) comprising: c) removing the aqueous and organic phases from the recycled polyolefin; d) recycling one or both of the aqueous and organic phases. may include:

[0029] Recycled polyolefins preferably contain hydrophilic and hydrophobic volatile organic compounds, which typically originate from contamination during the polymer's original use, often when the polymer is used as a packaging material, especially for food and / or personal care compositions.

[0030] The recycled polyolefin preferably contains at least one, and preferably all, of the group of hydrophilic volatile compounds consisting of 2,3-butanediol, 2-pentanone and benzaldehyde.

[0031] It is further preferred that the recycled polyolefin contains at least one, and preferably all, of the group of hydrophobic volatile compounds consisting of styrene, 2-ethyl-1-hexanol, 2-nonanone, D-limonene, 5-(2-methylpropyl)-nonane and 2,6-dimethyldecane.

[0032] It is particularly preferred that the recycled polyolefin contains at least one, preferably all, of the group of hydrophilic volatile compounds consisting of 2,3-butanediol, 2-pentanone and benzaldehyde, and at least one, preferably all, of the group of hydrophobic volatile compounds consisting of styrene, 2-ethyl-1-hexanol, 2-nonanone, D-limonene, 5-(2-methylpropyl)-nonane and 2,6-dimethyldecane.

[0033] Recycled polyolefins are preferably derived from post-consumer (post-consumer), (post-)industrial, or a combination thereof, and most preferably are derived from post-consumer.

[0034] Post-consumer waste refers to objects that have completed at least their first use cycle (or life cycle), i.e. have already fulfilled their first purpose, whereas post-industrial waste refers to production scrap, which usually does not reach the consumer.

[0035] The recycled polyolefin is preferably provided in flake or pellet form.

[0036] Although the process of the present invention is effective in removing hydrophobic and hydrophilic volatile organic compounds from recycled polyolefins in flake or pellet form, it is preferred that the recycled polyolefins be shredded prior to treatment with emulsion (E) in step (b), which has been found to improve extraction of the hydrophobic and hydrophilic volatile organic compounds, both as a result of a larger available surface area and improved ease of agitation, if agitation is required.

[0037] It is further preferred that the combination of emulsion (E) and recycled polyolefin in step (b) is subjected to mechanical mixing, ultrasonication, mechanical grinding or agitation by pump around loop, which helps to expose the surface of the recycled polyolefin to emulsion (E) and avoids high concentration of extracted volatile organic compounds at the interface hindering further extraction.

[0038] As those skilled in the art will understand, all polyolefins typically contain a fraction that is soluble in organic solvents, and many polyolefins are characterized by their hexane-soluble or xylene-soluble fractions. Although a small amount of polyolefin dissolution may be tolerated, it is better not to dissolve too much recycled polyolefin. Therefore, those skilled in the art will understand that it is necessary to avoid using an excessive amount of organic solvent in step b). Minimizing the amount of organic solvent used will also be advantageous from an economic point of view.

[0039] Preferably, the recycled polyolefin and the emulsion (E) are present in step b) in a weight ratio ranging from 5:95 to 67:33, most preferably in the range from 5:95 to 45:55.

[0040] Step (c) involves the removal of emulsion (E) from the recycled polyolefin. This may be accomplished by a stepwise process in which the aqueous phase is removed first, followed by the organic phase, or the organic phase is removed first, followed by the aqueous phase, or through a single step in which both phases are removed together. This process is relatively simple to accomplish by decanting and / or filtering the mixture, but traces of emulsion (E) and / or either the aqueous or organic phase may remain on the surface of the recycled polyolefin. These traces of emulsion (E) and / or either the aqueous or organic phase may contain solubilized volatile organic compounds, and therefore it is advantageous to remove all traces of emulsion (E).

[0041] This may be accomplished through the use of a rinsing process, whereby any foreign matter and / or aqueous solutions are rinsed from the surface of the recycled polyolefin.

[0042] Therefore, the process preferably comprises an additional step (c2) of rinsing the residues of the emulsion (E) and / or any other foreign matter and / or decomposition products thereof from the recycled polyolefin, this step being carried out after step (c).

[0043] In addition to or instead of the rinsing step (c2), the process preferably comprises an additional step (c3) of drying the recycled polyolefin, which is carried out after step (c) or after step (c2) if it is present. This drying step removes any residual aqueous phase, organic phase or rinsing solution that may be present on the surface of the recycled polyolefin.

[0044] The treatment of the recycled polyolefin with the emulsion (E) obtained in step (b) is a washing step as opposed to a rinsing step as defined herein and, as a result, typically lasts for more than 5 minutes, for example from 5 minutes to 5 hours.

[0045] The treatment of the recycled polyolefin with the emulsion (E) obtained in step (b) preferably lasts from 5 minutes to 4 hours, preferably from 30 minutes to 3 hours, most preferably from 1 to 2 hours.

[0046] It is further preferred that step (b) is carried out at a temperature in the range of 10 to 90°C, more preferably in the range of 20 to 50°C.

[0047] Step (b) is typically carried out without artificially increasing or decreasing the pressure, and therefore step (b) is preferably carried out at a pressure in the range of 0.5 to 2.0 atm, more preferably in the range of 0.8 to 1.5 atm, and most preferably at 1.0 atm.

[0048] The processes described above and below result in at least partial removal of volatile organic compounds from recycled polyolefins.

[0049] It is particularly preferred that the content of at least one hydrophilic volatile organic compound in the recycled polyolefin obtained as a product of the process, as measured by HS-GC / MS, is reduced by at least 90% relative to the content measured before the process, and that the content of at least one hydrophobic volatile organic compound in the recycled polyolefin obtained as a product of the process, as measured by HS-GC / MS, is reduced by at least 90% relative to the content measured before the process.

[0050] Although there are many hydrophilic volatile organic compounds that may be present in recycled polyolefins, often varying from batch to batch, there are some (numbers) that are particularly useful for determining the effectiveness of the process of the present invention due to their ease of detection and ubiquity in recycled polyolefins. Therefore, it is preferred to assess the individual content of hydrophilic volatile compounds by detection of 2,3-butanediol, 2-pentanone, and benzaldehyde.

[0051] Therefore, it is further preferred that at least one of the individual contents of 2,3-butanediol, 2-pentanone and benzaldehyde in the recycled polyolefin obtained as a product of the process, as measured by HS-GC / MS, is reduced by at least 90% relative to the content measured before the process.

[0052] It is even more preferred that the individual contents of 2,3-butanediol, 2-pentanone and benzaldehyde in the recycled polyolefin obtained as the product of the process, as measured by HS-GC / MS, are all reduced by at least 90% relative to the contents measured before the process.

[0053] Similarly, there are numerous hydrophobic volatile organic compounds that may be present in recycled polyolefins, often varying from batch to batch. Similar to the situation with hydrophilic volatile organic compounds, it is preferable to assess the individual content of hydrophobic volatile compounds by detection of styrene, 2-ethyl-1-hexanol, 2-nonanone, D-limonene, 5-(2-methylpropyl)-nonane and 2,6-dimethyldecane.

[0054] Therefore, it is further preferred that at least one of the individual contents of styrene, 2-ethyl-1-hexanol, 2-nonanone, D-limonene, 5-(2-methylpropyl)-nonane and 2,6-dimethyldecane in the recycled polyolefin obtained as a product of the process, as measured by HS-GC / MS, is reduced by at least 90% relative to the content measured before the process.

[0055] It is even more preferred that the individual contents of styrene, 2-ethyl-1-hexanol, 2-nonanone, D-limonene, 5-(2-methylpropyl)-nonane and 2,6-dimethyldecane, as measured by HS-GC / MS, are all reduced by at least 90% relative to the contents measured before the process.

[0056] In a particularly preferred embodiment, the individual contents of 2,3-butanediol, 2-pentanone, benzaldehyde, styrene, 2-ethyl-1-hexanol, 2-nonanone, D-limonene, 5-(2-methylpropyl)-nonane and 2,6-dimethyldecane, as measured by HS-GC / MS, are all reduced by at least 90% relative to the contents measured before the process.

[0057] Emulsion (E) The emulsion (E) of the present invention is i) an aqueous phase having a pH in the range of 7.0 to 14.0; ii) an organic phase comprising at least 90% v / v of one or more fully saturated organic solvents having a logP value in the range of 1.0 to 10.0; Includes.

[0058] Those skilled in the art will recognize that emulsion may contain additional phases that are immiscible with the above-mentioned aqueous and organic phases, and in fact such complex emulsions are not excluded from the present invention. These complex emulsions may have advantages, especially in the removal of special volatile organic compounds. However, in the context of the present invention, it is preferred that emulsion (E) is composed of the above-mentioned aqueous and organic phases, because this leads to an operationally simple process.

[0059] Emulsion (E) of the present invention may be pre-formed prior to contacting with the recycled polyolefin in step (b), or alternatively, the aqueous phase and the organic phase may be added separately to the recycled polyolefin and emulsion (E) produced during step (b).

[0060] Binary emulsions containing an aqueous phase and an organic phase are classified as either oil-in-water emulsions or water-in-oil emulsions, depending on which components form the dispersed phase and which components form the continuous phase. Which components form the dispersed phase and which components form the continuous phase can usually be predicted from the relative amounts (i.e., ratios) of the phases.

[0061] In the discussion that follows, the terms "oil" and "water" correspond to "organic phase" and "aqueous phase," respectively.

[0062] The relative contents of the organic phase and the aqueous phase are not particularly limited in the present invention. The ratio of water to oil is preferably in the range of 1:99 to 99:1, more preferably in the range of 5:95 to 99:5.

[0063] In one embodiment, the emulsion (E) of the present invention is an oil-in-water emulsion, and the water to oil ratio is in the range of 50:50 to 99:1, more preferably in the range of 80:20 to 95:5.

[0064] In another embodiment, the emulsion (E) of the present invention is a water-in-oil emulsion, the oil to water ratio being in the range of 50:50 to 99:1, more preferably in the range of 80:20 to 95:5.

[0065] The exact ratio between water and oil in the emulsion (E) is not critical to achieve effective removal of volatile organic compounds, but there are other advantages to certain ratios. In particular, ratios between 80:20 and 95:5 are useful when recycling of the main components is to be achieved. Furthermore, the organic phase, although relatively inexpensive, is more expensive to use than water due to waste stream management considerations. Thus, embodiments in which the water to oil ratio is in the range of 80:20 to 95:5 are particularly preferred from an economic standpoint, especially when recycling of the aqueous phase is desired. This embodiment is further advantageous to avoid excess polyolefin dissolution in the organic phase.

[0066] The pH of the aqueous phase is in the range of 7.0 to 14.0, preferably in the range of 7.0 to 11.0, and most preferably in the range of 7.0 to 9.0.

[0067] The aqueous phase may contain various additives, such as surfactants, to improve the removal of volatile organic compounds or to improve the stability of the emulsion, however, for reasons of process economics it is particularly preferred that the aqueous phase consists essentially of water.

[0068] The organic phase of the emulsion (E) must be highly stable and non-reactive with respect to the extracted volatile organic compounds, the aqueous phase and the recycled polyolefin, and furthermore, its polarity must be such that an emulsion is formed with the aqueous phase.

[0069] Therefore, the organic phase must contain at least 90% v / v of one or more fully saturated organic solvents having a logP value in the range of 1.0 to 10.0.

[0070] The organic phase preferably contains at least 95% v / v of one or more fully saturated organic solvents having a logP value in the range of 1.0 to 10.0, more preferably contains at least 98% v / v of one or more fully saturated organic solvents having a logP value in the range of 1.0 to 10.0, and most preferably the organic phase consists of one or more fully saturated organic solvents having a logP value in the range of 1.0 to 10.0.

[0071] In a particularly preferred embodiment, the organic phase comprises at least 90% v / v, more preferably 95% v / v, even more preferably at least 98% v / v of a fully saturated organic solvent having a single logP value in the range of 1.0 to 10.0, and most preferably consists of a single fully saturated organic solvent having a logP value in the range of 1.0 to 10.0.

[0072] The fully saturated organic solvent is preferably selected from the group of linear and branched alkanes and ethers (i.e., containing only carbon, hydrogen and optionally oxygen), more preferably from the group of linear and branched alkanes (i.e., containing only carbon and hydrogen).

[0073] The fully saturated organic solvent must have a log P value in the range of 1.0 to 10.0, more preferably in the range of 2.0 to 8.0, and most preferably in the range of 3.0 to 6.0.

[0074] use The present invention is also directed to the use of the above process and to the use of the above emulsion (E). All preferred features and preferred embodiments apply equally to the use of the process and to the use of emulsion (E) as to the process itself.

[0075] In one embodiment, the present invention is directed to the use of the above process for at least partially removing volatile organic compounds from recycled polyolefins.

[0076] In another embodiment, the present invention provides a process for at least partially removing volatile organic compounds from recycled polyolefins, comprising: a) an aqueous phase having a pH in the range of 7.0 to 14.0; b) an organic phase containing at least 90% v / v of one or more fully saturated organic solvents having a logP value in the range of 1.0 to 10.0; The present invention is directed to the use of an emulsion (E) comprising

[0077] In both of these uses, it is preferred that the content of at least one hydrophilic volatile organic compound in the recycled polyolefin obtained as a product of the process, as measured by HS-GC / MS, is reduced by at least 90% relative to the content measured before the process or use of emulsion (E), and that the content of at least one hydrophobic volatile organic compound in the recycled polyolefin obtained as a product of the process, as measured by HS-GC / MS, is reduced by at least 90% relative to the content measured before the process or use of emulsion (E).

[0078] It is further preferred that at least one of the individual contents of 2,3-butanediol, 2-pentanone and benzaldehyde in the recycled polyolefin obtained as a product of the process, as measured by HS-GC / MS, is reduced by at least 90% relative to the content measured before the process or use of emulsion (E).

[0079] It is even more preferred that the individual contents of 2,3-butanediol, 2-pentanone and benzaldehyde in the recycled polyolefin obtained as the product of the process, as measured by HS-GC / MS, are all reduced by at least 90% relative to the contents measured before the process or use of emulsion (E).

[0080] It is further preferred that at least one of the individual contents of styrene, 2-ethyl-1-hexanol, 2-nonanone, D-limonene, 5-(2-methylpropyl)-nonane and 2,6-dimethyldecane in the recycled polyolefin obtained as a product of the process, as measured by HS-GC / MS, is reduced by at least 90% relative to the content measured before the process or use of emulsion (E).

[0081] It is even more preferred that the individual contents of styrene, 2-ethyl-1-hexanol, 2-nonanone, D-limonene, 5-(2-methylpropyl)-nonane and 2,6-dimethyldecane, as measured by HS-GC / MS, are all reduced by at least 90% relative to the contents measured before the process or use of emulsion (E).

[0082] In a particularly preferred embodiment, the individual contents of 2,3-butanediol, 2-pentanone, benzaldehyde, styrene, 2-ethyl-1-hexanol, 2-nonanone, D-limonene, 5-(2-methylpropyl)-nonane and 2,6-dimethyldecane, as measured by HS-GC / MS, are all reduced by at least 90% relative to the contents measured before the process or use of emulsion (E).

[0083] The present invention may further be characterized by the following:

[0084] 1. A process for treating recycled polyolefins comprising, in the order listed, a) providing a recycled polyolefin containing volatile organic compounds; b) The recycled polyolefin i) an aqueous phase having a pH in the range of 7.0 to 14.0; and ii) an organic phase containing at least 90% v / v of one or more fully saturated organic solvents having a logP value in the range of 1.0 to 10.0; and contacting the emulsion (E) with the emulsion (E) comprising: c) removing the aqueous and organic phases from the recycled polyolefin; A process including.

[0085] 2. A process for treating recycled polyolefins comprising, in the order listed, a) providing a recycled polyolefin containing volatile organic compounds; b) The recycled polyolefin i) an aqueous phase having a pH in the range of 7.0 to 14.0; and ii) an organic phase containing at least 90% v / v of one or more fully saturated organic solvents having a logP value in the range of 1.0 to 10.0; and contacting the emulsion (E) with the emulsion (E) comprising: c) removing the aqueous and organic phases from the recycled polyolefin; d) recycling one or both of the aqueous and organic phases. A process including.

[0086] 3. The process according to claim 1 or 2, wherein the recycled polyolefin in step (a) is in flake or pellet form.

[0087] 4. The process according to claim 3, wherein the recycled polyolefin in flake or pellet form is shredded prior to step (b).

[0088] 5. The process according to any one of claims 1 to 4, wherein step (b) is carried out at a temperature in the range of 10 to 90°C.

[0089] 6. The process according to any one of items 1 to 5, wherein step (b) is carried out at a pressure in the range of 0.5 to 2.0 atmospheres.

[0090] 7. The process according to any one of items 1 to 6, wherein step (b) is carried out for a time period ranging from 5 minutes to 5 hours.

[0091] 8. The process according to any one of claims 1 to 7, wherein the recycled polyolefin and the emulsion (E) are present in step b) in a weight ratio ranging from 5:95 to 67:33.

[0092] 9. The process according to any one of claims 1 to 8, wherein the recycled polyolefin and the emulsion (E) are present in step b) in a weight ratio ranging from 5:95 to 45:55.

[0093] 10. The process according to any one of items 1 to 9, wherein the ratio of water to oil in the emulsion (E) is in the range of 1:99 to 99:1.

[0094] 11. The process according to any one of items 1 to 10, wherein the ratio of water to oil in the emulsion (E) is in the range of 5:95 to 95:5.

[0095] 12. The process according to any one of items 1 to 9, wherein the emulsion (E) is an oil-in-water emulsion, the ratio of water to oil being in the range of 50:50 to 99:1.

[0096] 13. The process according to any one of items 1 to 9, wherein the emulsion (E) is an oil-in-water emulsion, the ratio of water to oil being in the range of 80:20 to 95:5.

[0097] 14. The process according to any one of items 1 to 9, wherein the emulsion (E) is a water-in-oil emulsion, the ratio of oil to water being in the range of 50:50 to 99:1.

[0098] 15. The process according to any one of items 1 to 9, wherein the emulsion (E) is a water-in-oil emulsion, the ratio of oil to water being in the range of 80:20 to 95:5.

[0099] 16. The process of any one of the preceding claims, wherein the emulsion (E) is preformed prior to contacting with the recycled polyolefin in step (b).

[0100] 17. The process according to any one of the preceding claims, wherein the aqueous phase and the organic phase are added separately to the recycled polyolefin, and an emulsion (E) is produced during step (b).

[0101] 18. The process according to any one of claims 1 to 17, wherein the one or more fully saturated organic solvents are selected from the group of linear and branched alkanes and ethers.

[0102] 19. The process according to any one of claims 1 to 17, wherein the one or more fully saturated organic solvents are selected from the group of linear and branched alkanes.

[0103] 20. The process according to any one of the preceding claims, wherein the combination of recycled polyolefins and emulsion (E) obtained in step (b) is subjected to mechanical mixing, ultrasonic treatment, mechanical grinding or agitation by a pump-around loop.

[0104] 21. The process according to any one of the preceding claims, wherein the process comprises an additional step (c2) of rinsing the residues of the emulsion (E) and / or any other foreign matter and / or decomposition products thereof from the recycled polyolefin, said additional step (c2) being carried out after step (c).

[0105] 22. The process according to any one of the preceding claims, wherein the process comprises an additional step (c3) of drying the recycled polyolefin, which additional step (c3) is carried out after step (c) or, if present, after step (c2).

[0106] 23. The process according to any one of claims 1 to 22, wherein the aqueous phase removed in step (c) is recycled.

[0107] 24. The process according to any one of claims 1 to 23, wherein the recycled polyolefin is derived from post-consumer waste, post-industrial waste, or a combination thereof.

[0108] 25. The process according to any one of claims 1 to 24, wherein the recycled polyolefin is derived from post-consumer waste.

[0109] 26. The process according to any one of claims 1 to 25, wherein the recycled polyolefin contains at least one, preferably all, of the group of hydrophilic volatile compounds consisting of 2,3-butanediol, 2-pentanone and benzaldehyde.

[0110] 27. The process according to any one of claims 1 to 26, wherein the recycled polyolefin contains at least one, preferably all, of the group of hydrophobic volatile compounds consisting of styrene, 2-ethyl-1-hexanol, 2-nonanone, D-limonene, 5-(2-methylpropyl)-nonane and 2,6-dimethyldecane.

[0111] 28. The process according to any one of claims 1 to 27, wherein the process is for at least partially removing volatile organic compounds from the recycled polyolefins.

[0112] 29. The process according to item 28, wherein the content of at least one hydrophilic volatile organic compound in the recycled polyolefin obtained as a product of the process, as measured by HS-GC / MS, is reduced by at least 90% relative to the content measured before the process, and the content of at least one hydrophobic volatile organic compound in the recycled polyolefin obtained as a product of the process, as measured by HS-GC / MS, is reduced by at least 90% relative to the content measured before the process.

[0113] 30. The process according to item 29, wherein at least one of the individual contents of 2,3-butanediol, 2-pentanone and benzaldehyde in the recycled polyolefin obtained as a product of the process, as measured by HS-GC / MS, is reduced by at least 90% relative to the content measured before the process.

[0114] 31. The process according to item 29, wherein the individual contents of 2,3-butanediol, 2-pentanone and benzaldehyde in the recycled polyolefin obtained as a product of the process, as measured by HS-GC / MS, are all reduced by at least 90% relative to the contents measured before the process.

[0115] 32. The process according to any one of items 29 to 31, wherein at least one of the individual contents of styrene, 2-ethyl-1-hexanol, 2-nonanone, D-limonene, 5-(2-methylpropyl)-nonane and 2,6-dimethyldecane in the recycled polyolefin obtained as a product of the process is reduced by at least 90% relative to the content measured before the process, as measured by HS-GC / MS.

[0116] 33. The process according to any one of items 29 to 31, wherein the individual contents of styrene, 2-ethyl-1-hexanol, 2-nonanone, D-limonene, 5-(2-methylpropyl)-nonane and 2,6-dimethyldecane, as measured by HS-GC / MS, are all reduced by at least 90% relative to the contents measured before the process.

[0117] 34. Use of the process according to any one of items 1 to 27 for at least partially removing volatile organic compounds from recycled polyolefins.

[0118] 35. Use according to item 34, in which the content of at least one hydrophilic volatile organic compound, measured by HS-GC / MS, is reduced by at least 90% relative to the content measured before the process, and the content of at least one hydrophobic volatile organic compound, measured by HS-GC / MS, is reduced by at least 90% relative to the content measured before the process.

[0119] 36. The use according to item 35, wherein at least one of the individual contents of 2,3-butanediol, 2-pentanone and benzaldehyde in the recycled polyolefin obtained as a product of the process, as measured by HS-GC / MS, is reduced by at least 90% relative to the content measured before the process.

[0120] 37. The use according to item 35, wherein the individual contents of 2,3-butanediol, 2-pentanone and benzaldehyde in the recycled polyolefin obtained as a product of the process, as measured by HS-GC / MS, are all reduced by at least 90% relative to the contents measured before the process.

[0121] 38. The use according to any one of items 35 to 37, wherein at least one of the individual contents of styrene, 2-ethyl-1-hexanol, 2-nonanone, D-limonene, 5-(2-methylpropyl)-nonane and 2,6-dimethyldecane in the recycled polyolefin obtained as a product of the process, as measured by HS-GC / MS, is reduced by at least 90% relative to the content measured before the process.

[0122] 39. The use according to any one of items 35 to 37, wherein all of the individual contents of styrene, 2-ethyl-1-hexanol, 2-nonanone, D-limonene, 5-(2-methylpropyl)-nonane and 2,6-dimethyldecane in the recycled polyolefin obtained as a product of the process, as measured by HS-GC / MS, are reduced by at least 90% relative to the contents measured before the process.

[0123] 40. A method for at least partially removing volatile organic compounds from recycled polyolefins, a) an aqueous phase having a pH in the range of 7.0 to 14.0; b) an organic phase containing at least 90% v / v of one or more fully saturated organic solvents having a logP value in the range of 1.0 to 10.0; Use of an emulsion (E) comprising:

[0124] 41. The use according to item 40, wherein the content of at least one hydrophilic volatile organic compound in the recycled polyolefin obtained as a product of the process, as measured by HS-GC / MS, is reduced by at least 90% relative to the content measured before the process, and the content of at least one hydrophobic volatile organic compound in the recycled polyolefin obtained as a product of the process, as measured by HS-GC / MS, is reduced by at least 90% relative to the content measured before the process.

[0125] 42. The use according to item 41, wherein at least one of the individual contents of 2,3-butanediol, 2-pentanone and benzaldehyde in the recycled polyolefin obtained as a product of the process, as measured by HS-GC / MS, is reduced by at least 90% relative to the content measured before the process.

[0126] 43. The use according to item 41, wherein the individual contents of 2,3-butanediol, 2-pentanone and benzaldehyde in the recycled polyolefin obtained as a product of the process, as measured by HS-GC / MS, are all reduced by at least 90% relative to the contents measured before the process.

[0127] 44. The use according to any one of items 41 to 43, wherein at least one of the individual contents of styrene, 2-ethyl-1-hexanol, 2-nonanone, D-limonene, 5-(2-methylpropyl)-nonane and 2,6-dimethyldecane in the recycled polyolefin obtained as a product of the process, as measured by HS-GC / MS, is reduced by at least 90% relative to the content measured before the process.

[0128] 45. The use according to any one of items 41 to 43, wherein all of the individual contents of styrene, 2-ethyl-1-hexanol, 2-nonanone, D-limonene, 5-(2-methylpropyl)-nonane and 2,6-dimethyldecane in the recycled polyolefin obtained as a product of the process, as measured by HS-GC / MS, are reduced by at least 90% relative to the contents measured before the process. EXAMPLES

[0129] 1. Definition / determination method Determination of Volatile Organic Compounds Content by HS-GC / MS Static headspace analysis for the determination of marker substances. The headspace gas chromatography mass spectrometry (HS / GC / MS) method parameters applied are described here. For the measurement of benzene standards, 5 μl of a standard solution containing 100 μg / ml benzene in methanol was injected into a 20 ml HS vial and sealed with a PTFE cap. Each HS / GC / MS test sequence of sample measurements included the analysis of such a benzene standard. The benzene signals of the corresponding sequences were used for the calculation of the relative normalized areas, which are further described below. Samples were also analyzed by HS / GC / MS to determine potential odorants and hazardous marker substances. Therefore, 2.000±0.100 g of sample was weighed into 20 ml HS vials and sealed with PTFE caps. Duplicate measurements of each sample were performed for each cleaning experiment. Headspace parameters applied for the analysis of standards and samples differed in vial equilibration time and HS oven temperature. Otherwise, method parameters were kept the same for standard and sample runs. The mass spectrometer was operated in scan mode and total ion chromatograms (TICs) were recorded for each analysis. Detected substances were tentatively identified with the help of deconvolution, followed by a minimum match of 800 when comparing hits to the mass spectral library. More detailed information on the method parameters and data evaluation software is provided below. ·HS parameters (Shimadzu AOC 5000 headspace sampler) Vial equilibration time: 120 minutes Oven temperature: 100℃ Syringe temperature: 110℃ ·GC parameters (Shimadzu GC-MS-QP2010) Column: DB-FATWAX UI UST 446421H (30m x 250μm x 0.25μm) Carrier gas: Helium 5.0 Flow rate: 1.3ml / min Split: 5:1 GC oven program: 35°C, 2 min 10°C / min up to 250°C 250℃ 5 minutes MS parameters (Agilent 5975C inert XL MSD) Acquisition mode: Scan Scan parameters: Low mass: 27 High mass: 200 Threshold: 10 Software / Data Evaluation MSD ChemStation E.02.02.1431 MassHunter GC / MS Acquisition B.07.05.2479 AMDIS GC / MS Analysis Version 2.71 NIST Mass Spectral Library (Version 2011) Microsoft Excel (registered trademark) 2016

[0130] Data Evaluation The benzene standards were evaluated with the same parameters as the sample runs. Therefore, extracted ion chromatograms (EICs) of the measured benzene standards and samples were generated. The peak areas required for further data evaluation were obtained by integrating the corresponding substance peaks in the EICs. The applied integration parameters and substance-specific ions (m / z ratios) of all marker substances are listed in Tables 1 and 2.

[0131] [Table 1]

[0132] In general, it is not possible to exclude the possibility of overlapping peaks in some regions of the HS-GC / MS readout, but this has not been observed to significantly affect the values ​​obtained in the data presented in this application.

[0133] [Table 2]

[0134] The area of ​​the substance-specific ion peak (EIC) X ) was calculated by dividing the extracted ion peak area (EIC) of benzene by the ベンゼン ) and normalized by the sample amount to obtain the normalized area (normalized area X , see formula 1) was obtained.

number

[0135] For each cleaning experiment, two individual analyses (normalized area X1 , normalized area X2 ) normalized average area (

number

number

[0136] Relative normalized area (Relative normalized area X ), the normalized average area (

number

number

[0137] For the purposes of data evaluation, three different cases must be distinguished. 1) The substance-specific ion peaks were estimable in both analytical runs of the duplicate measurements. The relative normalized areas were obtained by applying Equations 1, 2, and 3 as follows: 2) The substance-specific ion peaks could only be evaluated in one analytical run of duplicate measurements. As a result, the normalized average area (

number

[0138] To estimate the deviation of two individual analyses of one corresponding cleaning experiment, the relative standard deviation (RSD X ) was calculated (applicable only to case 1). Therefore, by using the Excel function STDEV.S, the two normalized areas (normalized area X1 , normalized area X2 The standard deviation of RSD was calculated. X To calculate the standard deviation (STDEV.S), we normalize the average area (

number

number

[0139] The above standard deviation is the relative normalized area X To make it about RSD X is expressed as the relative normalized area, X and multiplied it. Relative RSD X = RSD X × Relative normalized area X formula 5

[0140] 2. Experimental Results In the following experiments the materials used were as follows: Recycled polyolefin (recycled polyolefin) The recycled polyolefin used in the following experiments was obtained from mtm plastics GmbH, Niedergebra, Germany, and is the pre-sorted unwashed polymer mixture used by mtm plastics GmbH in the preparation of Dipolen S. As a result, the composition of this recycled polyolefin in terms of polyethylene and polypropylene content is identical to that of Dipolen S. However, the content of small molecule contaminants is likely to be different.

[0141] Dipolen S is a recycled polymer blend containing polyethylene and polypropylene obtained from mtm plastics GmbH, Niedergebra, Germany, with a polyethylene content of 40 wt.% as determined by DSC analysis. The melting points determined by DSC were 162° C. (PP) and 128° C. (PE).

[0142] In the following experiments, the recycled polyolefin was obtained in flake form and then freeze-grinded prior to the following experiments, allowing the experiments to be carried out on a smaller scale than would be the case for an industrial process.

[0143] The "cleaning efficiency" was calculated according to the following formula:

number

[0144] Experimental procedure Example 1 90 ml of water and 10 ml of heptane were added to a 250 ml beaker equipped with a magnetic stirrer and an overhead ultrasonic probe (UP400S from Hielscher Ultrasonics GmbH with a sonotrode of 40 mm diameter; 400 W, 24 kHz) was inserted into the liquid at approximately 75% of the liquid volume height. The magnetic stirrer and ultrasonicator were turned on and after 2 min, 10 g of the cryo-ground polymer powder was added to the emulsion and the suspension was subsequently stirred and sonicated for 1 h. The washing solvent mixture was then removed by filtration and the polymer powder was rinsed twice with water, each of which was performed by contacting the polymer powder with 100 ml of demineralized water for 30 seconds, followed by removal of the water by filtration, and then drying the polymer powder in a vacuum oven at 70° C. for 1 hour.

[0145] Example 2 As in Example 1, except that 50 ml of water and 50 ml of heptane was used as the wash solvent mixture instead of 90 ml of water and 10 ml of heptane.

[0146] Example 3 As in Example 1, except that 10 ml of water and 90 ml of heptane was used as the wash mixture instead of 90 ml of water and 10 ml of heptane.

[0147] Example 4 As in Example 1, except that an Ultraturrax device (IKA T-18 Ultra Turrax Homogenizer) was used instead of an overhead ultrasound probe.

[0148] Example 5 As in Example 4, except that a cooling bath was used to maintain the temperature at about 20° C. during the water-heptane emulsion washes.

[0149] Comparative Example 1 100 ml of water as washing solvent was added to a 250 ml beaker equipped with a magnetic stirrer and an overhead ultrasonic probe (UP400S from Hielscher Ultrasonics GmbH with a sonotrode of 40 mm diameter; 400 W, 24 kHz) was inserted into the liquid at about 75% of the liquid volume height. 10 g of freeze-ground polymer powder was then added and the stirred suspension was sonicated for 1 h. The liquid phase was then removed by filtration and the polymer powder was rinsed twice with water. Each of these rinsing steps consisted of contacting the polymer powder with 100 ml of demineralized water for 30 seconds, followed by removal of the water by filtration. The polymer powder was then dried in a vacuum oven at 70° C. for 1 h.

[0150] Comparative Example 2 As in Comparative Example 1, except that 100 ml of heptane was used as the washing solvent instead of 100 ml of water.

[0151] [Table 3] * The logP values ​​of the volatile organic compounds tested were not experimentally determined, but are generally accepted literature values, i.e. 1 National Center for Biotechnology Information(2020). PubChem Compound Summary for CID 262, 2,3-Butanediol. Retrieved November 13, 2020 from https: / / pubchem.ncbi.nlm.nih.gov / compound / 2_3-Butanediol 2 James Sangster, Octanol-Water Partition Coefficients of simple organic compounds. J.Phys.Chem.Ref.Data, 1989, Vol. 18, No. 3, 1111-1226 3National Center for Biotechnology Information(2020). PubChem Compound Summary for CID 7720, 2-Ethylhexanol. Retrieved November 13, 2020 from https: / / pubchem.ncbi.nlm.nih.gov / compound / 2-Ethylhexanol 4 National Center for Biotechnology Information(2020). PubChem Compound Summary for CID 22311, Limonene. Retrieved November 13, 2020, from https: / / pubchem.ncbi.nlm.nih.gov / compound / Limonene 5 https: / / www.chemsrc.com / en / cas / 62185-53-9_216142.html 6 https: / / www.chemsrc.com / en / cas / 13150-81-7_122290.html can be found in.

[0152] [Table 4]

[0153] As can be seen from Table 4, the cleaning efficiency of the emulsions, whether they are water-in-oil or oil-in-water emulsions, is superior to using either water or heptane individually. Aqueous washes (i.e., using only water) typically have a lower efficiency for removing hydrophilic volatile organic compounds, and heptane washes are typically not effective enough in removing hydrophilic volatile organic compounds.

[0154] Of particular importance is the availability of a 90:10 water / heptane emulsion, which allows for the use of small amounts of heptane and easy recycling of the aqueous phase, both of which add economic benefits to the process.

[0155] Further minor improvements reflecting the importance of emulsion formation and shear forces can be seen when the Ultraturrax is used. The ice-cold Ultraturrax results show that it is these characteristics, and not the temperature, that are the drivers of improvement.

Claims

1. 1. A method for treating recycled polyolefins comprising, in the order listed, a) providing a recycled polyolefin containing volatile organic compounds; b) the recycled polyolefin, i) an aqueous phase having a pH in the range of 7.0 to 14.0, and ii) an organic phase comprising at least 90% v / v of one or more fully saturated organic solvents having a log P value in the range of 1.0 to 10.0, said fully saturated organic solvent being selected from the group consisting of linear and branched alkanes; and contacting the emulsion (E) with the emulsion (E) comprising: c) removing the aqueous phase and the organic phase from the recycled polyolefin; d) optionally recycling one or both of the aqueous and organic phases; Including, The method according to claim 1, wherein the volatile organic compound is any organic compound having an initial boiling point of 250° C. or less.

2. 10. The method of claim 1, wherein the recycled polyolefin of step (a) is in flake or pellet form.

3. The method described in claim 2, wherein the recycled polyolefin in flake or pellet form is shredded prior to step (b).

4. The process according to claim 1 or claim 2, wherein step (b) is carried out at a temperature in the range of from 10 to 90°C.

5. The method of claim 1 or claim 2, wherein step (b) is carried out for a time ranging from 5 minutes to 5 hours.

6. 3. The method according to claim 1 or claim 2, wherein the emulsion (E) is an oil-in-water emulsion, the ratio of water to oil being in the range of 50:50 to 99:

1.

7. 3. The method according to claim 1 or claim 2, wherein the emulsion (E) is a water-in-oil emulsion, the oil to water ratio being in the range of 50:50 to 99:

1.

8. 3. The method according to claim 1 or claim 2, wherein the combination of recycled polyolefins and emulsion (E) obtained in step (b) is subjected to mechanical mixing, ultrasonic treatment, mechanical grinding or agitation by a pump-around loop.

9. the process comprises an additional step (c2) of rinsing the residues of the emulsion (E) and / or any other foreign matter and / or decomposition products of said other foreign matter from the recycled polyolefin, said additional step (c2) being carried out after step (c); and / or 3. The method according to claim 1 or claim 2, wherein the method comprises an additional step (c3) of drying the recycled polyolefins, said additional step (c3) being carried out after step (c) or, if present, step (c2).

10. 3. The process according to claim 1 or claim 2, wherein the aqueous phase removed in step (c) is recycled.

11. 3. The method of claim 1 or claim 2, wherein the recycled polyolefin is derived from post-consumer waste, post-industrial waste, or a combination thereof.

12. 3. The method of claim 1 or claim 2 for at least partially removing volatile organic compounds from the recycled polyolefins.

13. the content of at least one hydrophilic volatile organic compound in the recycled polyolefin obtained as a product of the process is reduced by at least 90% relative to the content measured before the process, as measured by HS-GC / MS; 13. The method of claim 12, wherein the content of at least one hydrophobic volatile organic compound in the recycled polyolefin obtained as a product of the method, as measured by HS-GC / MS, is reduced by at least 90% relative to the content measured before the method.

14. 3. Use of the method according to claim 1 or claim 2 for at least partially removing volatile organic compounds from recycled polyolefins.

15. For at least partially removing volatile organic compounds from recycled polyolefins, a) an aqueous phase having a pH in the range of 7.0 to 14.0; b) an organic phase comprising at least 90% v / v of one or more fully saturated organic solvents having a log P value in the range of 1.0 to 10.0, said fully saturated organic solvent being selected from the group consisting of linear and branched alkanes; 2. Use of an emulsion (E) comprising:

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