Plastic recycling process aid

Abstract

A plastic recycling process aid comprising a composition comprising component (a) and component (b), wherein component (a) is at least one of an alkyl dialkylamide and alkene dialkylamide; and component (b) is selected from at least one alkoxylate wherein the composition forms a metastable composition upon mixing with an aqueous solution.

Description

Attorney Docket No. 102-P0585PCT PLASTIC RECYCLING PROCESS AID FIELD OF THE INVENTION

[0001] The invention relates to a plastic recycling process aid. More particularly, the invention relates to a plastic recycling aid comprising a composition comprising component (a) and component (b), wherein component (a) is at least one of an alkyl dialkylamide and alkene dialkylamide; and component (b) is selected from at least one nonionic alkoxylate, and wherein the composition forms a metastable composition upon mixing with an aqueous solution. BACKGROUND OF THE INVENTION

[0002] Plastic recycling has increasingly become an area of commercial interest in view of societal emphasis on green technologies and sustainability. In plastic recycling processes, there are multiple cleaning steps which require a high degree of cleaning performance achieved by both mechanical and chemical processes. The aqueous solution used in the cleaning process contains several cleaning ingredients such as solvents, surfactants, builders, defoamers, stabilizers, etc. The cleaning process, however, is difficult to standardize due to the complexity of the physical and chemical composition of the plastic materials, and this complexity demands a customized solution for the cleaning process. One of the non-constant parameters in the cleaning process is the cleaning temperature, which ranges from ambient temperature to as high as 90 °C, depending on the difficulty of overall cleaning. This temperature variation generally causes inconsistent cleaning performance of the solution. For example, the regular cleaning formulations which provide the best solution at ambient temperatures are not useful for the process and even provoke undesired results as the surfactants and solvents become insoluble with the increase of the temperature. One challenge that faces such recycling processes is the undesired adhesion of insoluble cleaning components from the cleaning solution to the plastic pieces at high temperature. Once the insoluble cleaning component adhesion occurs, the washing of it is difficult in further processing of the plastic recycling. This adhesion can cause many serious quality issues in recycled plastic. Specifically, the presence of the residual materials from cleaning solution affects the overall mechanical properties of the recycled plastic materials. Owing to these potential risks, the cleaningAttorney Docket No. 102-P0585PCT formulations for mechanical plastic recycling are typically homogeneous, stable, optically transparent aqueous solutions, which could potentially limit the operations at elevated temperature. More importantly, this homogeneity deters the recovery of the cleaning ingredients like surfactants and solvents after the cleaning process.

[0003] Various attempts have been made to develop improved cleaners for plastic materials. U.S. 5,330,581 is directed to the use of a surfactant to remove ink from plastic substrates, the surfactant being a trialkyl hydroxyalkyl ammonium salt. WO 2022234296 discloses the use of oxidants selected from chlorine dioxide, organic peracids, alkaline hypochlorites, hydrogen peroxide, alkaline perborates, and alkaline percarbonates for treating returnable plastic containers. U.S. 8,153,577 discloses the use of diacetic esters for recyclable plastic substrate cleaning. U.S. 20160115427 discloses a cleaning composition for label removal on plastics. U.S. 5,843,317 discloses a method for ultrafiltration recovery of an anionic surfactant from solution. U.S. 20040014624 discloses a recyclable cleaning composition containing an alkaline solution of at least one surfactant. U.S. 11,819,886 discloses cleaning recyclable clay with polyols. EP 3341462 discloses the use of acetate esters. U.S. 7,547,672 discloses a composition for cleaning and degreasing substrates including a 2-ethylhexyl esters. WO 20240201 discloses the use of alkyl glycol ethers with high HLB ethoxylates. Nevertheless, a continuing need exists for systems that can effectively use a non-homogeneous metastable cleaning solution allowing the recovery of the cleaning ingredients without the adhesion to the plastic materials during the cleaning and washing processes. SUMMARY OF THE INVENTION

[0004] The subject matter of the present disclosure relates to a plastic recycling process aid.

[0005] In one embodiment, the present disclosure provides a plastic recycling process aid comprising a composition comprising component (a) and component (b), wherein component (a) is at least one of an alkyl dialkylamide and alkene dialkylamide; and component (b) is selected from at least one nonionic alkoxylate, wherein the ratio of component (a) to component (b) is 20 / 1 to 1 / 20, and wherein the composition forms a metastable composition upon mixing with an aqueous solution.

[0006] In another embodiment, the present disclosure provides a process comprising administering the plastic recycling process aid described above in a plastic recycling process. 2 4930-1386-2932, v.1Attorney Docket No. 102-P0585PCT

[0007] In still another embodiment, the present disclosure provides a process for removing contaminants from plastic comprising mixing the plastic recycling process aid described above with an aqueous composition thereby forming a metastable wash solution, and contacting the metastable wash solution with a plastic comprising the contaminants, thereby forming a wash slurry; and then separating the wash slurry, thereby forming a separated plastic and a separated process aid, wherein the separated and washed plastic has a residue content of 0 to 1.0 wt% based on the weight of the separated and washed plastic, and wherein the contaminant level of the separated plastic is at least 40% lower than the plastic prior to contact with the plastic recycling process aid, based on the total weight of the separated plastic.

[0008] In another embodiment, the present disclosure provides a metastable wash solution comprising: 95.0 to 99.5 wt% of an aqueous composition; and 0.5 to 5.0 wt% of the plastic recycling process aid described above.

[0009] A process comprising cleaning recycled plastic in a plastic recycling process with the metastable wash solution. BRIEF DESCRIPTION OF THE DRAWINGS

[0010] Figure 1 illustrates the cloud point of high mole alkoxylates in the formulation study which was measured at a 1 wt% surfactant usage with 2 wt% NaOH (50 %).

[0011] Figure 2 illustrates the visual assessment of a formulation performance test with a PET substrate at 80 – 85oC and the effect of nonionic surfactant concentration on the solvent deposition (MET-10U).

[0012] Figure 3 illustrates a washing procedure of plastic materials (PET mixture) by using cleaning solutions.

[0013] Figure 4 illustrates the effect of STEPOSOL MET-10U (or MET-10U) and TSP-60 ratio on the % of solvent deposited on PET materials, where a 5 wt% of active is used in the formulation (e.g.5 wt% surfactant blend in 1% of NaOH (50%) solution), and where the dashed-line indicates 1% of solvent residue.

[0014] Figure 5 illustrates the effect of the alkyl chain structure of the amide on the percent of solvent deposited on PET materials, where 2 wt% of active is used in the formulation at a fixed 2:1 ratio of the amide and TSP-60, where the dashed line indicates 1% of solvent residue. 3 4930-1386-2932, v.1Attorney Docket No. 102-P0585PCT

[0015] Figure 6 illustrates the solvent deposition potential on PET substrate during the plastic cleaning process using 2% of a surfactant blend with 1 wt% NaOH (50%), at 80 – 85oC. Glycol ether is used as a replacement of the amide and the data of STEPOSOL MET-10U and HALLCOMID M-1225 are plotted together for the comparison. A gray bar indicates the formulation is hazy. A clear bar indicates the formulation is optically clear. DETAILED DESCRIPTION OF THE INVENTION

[0016] It has been unexpectedly discovered that particularly designed systems containing high mole ethoxylates and nonionic alkoxylates with dimethylamide type solvents provide superior cleaning with much less residue formation on the plastic. It is also possible to easily separate the dimethylamide type solvents and nonionic alkoxylates from the used cleaning solution and re-use it in the next cleaning cycle. The industry would greatly benefit from the ability to recycle the cleaning components while enhancing the cleaning performance and minimizing residual solvent on the recycled plastic.

[0017] In one embodiment, the present disclosure provides a plastic recycling process aid comprising a composition comprising component (a) and component (b), wherein component (a) is at least one of an alkyl dialkylamide and alkene dialkylamide; and component (b) is selected from at least one nonionic alkoxylate wherein the ratio of component (a) to component (b) is 20 / 1 to 1 / 20, wherein the composition forms a metastable composition upon mixing with an aqueous solution. Preferably, the ratio is 10 / 1 to 1 / 5. More preferably, the ratio is 5 / 1 to 1 / 1.

[0018] Plastic recycling process aid

[0019] Metastable Composition

[0020] For the purpose of this specification, the term metastable composition means a mixture of components (a) and (b), in an aqueous composition that form an emulsion that is inherently unstable (temporarily stable), meaning it can be easily separated into its constituent phases with the application of minimal separation force. It has an opaque appearance, a viscosity of 1 to 20 cP at 60 to 90 °C, and breaks down within 24 to 48 hours due to gravitational force or within 1 minute under a centrifugal force of 22.5 g or more. The requirement of opacity directly relates to the ability of a solution after washing of plastic, to readily separate into its constituent components, and be recycled. 4 4930-1386-2932, v.1Attorney Docket No. 102-P0585PCT

[0021] Specifically, to be considered metastable, component (b) can be fully dissolved into water and then the component (a) can be fully emulsified with component (b) initially under high shear mixing of at least above 3000 rpm at a temperature from 20 to 80 °C, but can be separated into its constituent phases by subjecting the emulsion to the elevated temperature from 60 to 80 °C for 24 to 48 hours or under a centrifugal force of 22.5 g or more for 1 minute.

[0022] Component (a): alkyl & alkene dialkylamides

[0023] The alkyl and alkene dialkylamides are typically selected from N,N-dimethyloctanamide (N,N-dimethylcaprylamide), N,N-dimethyl-decanamide (N,N-dimethylcapramide), N,N- dimethylnonanamide, N,N-demethyldecanamide, N,N-dimethyl-9-decenamide, N,N- dimethyldodecanamide, N,N-dimethyldodecanamide, (N,N-dimethyllauramide), N,N- dimethyltetradecanamide, (N,N-dimethylmyristamide), N,N-dimethyldodec-9-enamide, 2- butyloctyl dimethylamide, N,N-lauryl diethylamide, N,N-oleic dimethylamide, or mixtures thereof.

[0024] Preferably, the alkyl and alkene dialkylamides are typically selected from a C8– C18dimethylamide having a linear or branched structure in the alkyl or alkene chain. More preferably, the alkyl and alkene dialkylamides are selected from a C10 - C14 alkyl or alkene dimethylamide. These carbon number ranges have been particularly selected to meet the twin objectives of providing excellent cleaning capability, which is generally benefited from lower carbon numbers, and the ability in an emulsion formed with an aqueous composition, for the emulsion to be separated into its component parts, which is favored by higher carbon numbers.

[0025] Component (b)

[0026] Component (b) is typically selected from an alkyl phenol ethoxylate, a fatty oil ethoxylate, an alcohol alkoxylate, an alcohol ethoxylate, or a mixture thereof. Preferably, component (b) is selected from an aralkylated phenol ethoxylate, an ethoxylated C11– C14alcohol, an ethoxylated, propoxylated, branched C11-C14 alcohol, an ethoxylated lauryl alcohol, or mixtures thereof. More preferably, component (b) is selected from the aralkylated phenol ethoxylate, an ethoxylated branched C11-C13alcohol, an ethoxylated C12-C14lauryl alcohol, an ethoxylated, propoxylated branched C13 alcohol or mixtures thereof.

[0027] Preferably, component (b) is selected from an aralkylated phenol ethoxylate having an average of 8 to 70 EO, an ethoxylated, propoxylated, branched C13alcohol having an average of 30 to 60EO and 1 to 20PO, an ethoxylated branched C11alcohol having an average of 20 to 50 EO, 5 4930-1386-2932, v.1Attorney Docket No. 102-P0585PCT an ethoxylated branched C13alcohol having an average of 30 to 60 EO, an ethoxylated C12-14lauryl alcohol having an average of 20 to 50 EO or mixtures thereof.

[0028] Compositions containing components (a) & (b).

[0029] In the compositions containing components (a) & (b) the ratio of component (a) to component (b) is 20 / 1 to 1 / 20. Preferably, the plastic recycling process aid of claim 1 wherein the ratio is 10 / 1 to 1 / 5. More preferably the ratio is 5 / 1 to 1 / 1.

[0030] Preferably, in the plastic recycling process aid component (a) is present in an amount of 50.0 to 92.0 wt% and component (b) is present in an amount of 8.0 to 50.0 wt%, based on the total weight of the plastic recycling process aid. More preferably, in the plastic recycling process aid component (a) is present in the amount of 50.0 to 81.0 wt% and component (b) is present in the amount of 19.0 to 50.0 wt.%, based on the total weight of the plastic recycling process aid. Even more preferably, in the plastic recycling process aid component (a) is present in the amount of 60.0 to 70.0 wt% and component (b) is present in the amount of 30.0 to 40.0 wt%, based on the total weight of the plastic recycling process aid.

[0031] The surfactant and dimethylamide solvent can be separately added into the cleaning solution or they can be pre-blended as a single product. Pre-blending is preferred as the high mole ethoxylates or alkoxylates usually have high melting points and it could be inconvenient and require extra energy and heat to melt the product prior to use. Mixing with dimethylamide solvents improves the handling properties by decreasing melting point. Preferably, the melting point of a mixture of components (a) and (b) is less than 32.0 °C for a 2:1 mixture of component (a) : component (b).

[0032] In another embodiment, the present subject matter provides a process for removing contaminants from plastic comprising mixing the plastic recycling process aid described above with an aqueous composition, thereby forming a wash solution; contacting the plastic comprising the contaminants, thereby forming a wash slurry; and separating the wash slurry, thereby forming a separated plastic and a separated process aid, wherein the separated and washed plastic has a residue of 0 to 1.0%, based on the weight of the separated and washed plastic, and wherein the contaminant level of the separated plastic is at least 20 % lower than the plastic prior to contact with the wash solution. 6 4930-1386-2932, v.1Attorney Docket No. 102-P0585PCT

[0033] The contaminants removal process can further comprise demulsifying the separated process aid thereby forming a demulsified stream; and separating the demulsified stream into a first separated stream containing greater than 50% of component (a) and a second separated stream containing greater than 30% of component (b). Preferably, a weight ratio of plastic recycling process aid to plastic in the contacting step is 1 / 1 to 20 / 1, more preferably, 9 / 1 to 11 / 1. Examples of contaminants removed by the recycling process aid include labels, adhesive residue, ink or dyes, and additives contained therein. Preferably, the temperature of the contaminant removal process is 40.0 to 99.0 °C. More preferably, the temperature is from 50.0 to 95.0 °C. Most preferably, the temperature is from 60.0 to 90.0 °C.

[0034] In still another embodiment, the present subject matter provides a process comprising administering the plastic recycling process aid described above in a plastic recycling process.

[0035] In another embodiment, the present subject matter provides a metastable wash solution comprising: 95.0 to 99.5 wt% of an aqueous composition; and 0.5 to 5.0 wt% of the plastic recycling process aid containing components (a) & (b) as described above. The metastable wash solution can be used in the cleaning of recycled plastic in a plastic recycling process. Preferably, the aqueous composition is present in an amount of 97.0 to 99.0 wt% and the plastic recycling aid is present in an amount of 1.0 to 3.0 wt%. Preferably, the aqueous composition is alkaline. More preferably, the aqueous composition contains NaOH. Preferably, the weight ratio of component (a) / component (b) is 2:1 to 1:5.

[0036] EXAMPLES

[0037] The following examples further detail and explain the inventive compositions of the present disclosure and demonstrate the behavior of the plastic recycling aid in aqueous formulations, and the performance of cleaning solutions made by the plastic recycling aid primarily focusing on the cleaning ability, residue formation potential from cleaning solution, and the recovery of used cleaning solution.

[0038] Those skilled in the art will recognize many variations that are within the spirit of the invention and scope of the claims.

[0039] Table 1 summarizes chemicals that were used in the following examples. 7 4930-1386-2932, v.1Attorney Docket No. 102-P0585PCT

[0040] Table 1 Designation Description Manufacturer HALLCOMID M-8 STEPAN COMPANY8 4930-1386-2932, v.1Attorney Docket No. 102-P0585PCT Butyl Cellosolve (EGBE or Ethylene glycol monobutyl Dow 2-BE) ether

[0041] EXAMPLES

[0042] EXAMPLE A: DIALKYL ALKYL OR AlKENYL AMIDE AND NONIONIC ETHOXYLATE BLENDS

[0043] A blend of Makon TSP-60 (melted at 60 °C) and HALLCOMID M-10 is prepared at various ratios ranging from 4:1 to 1:10 by weight. Similarly, a mixture using STEPOSOL MET- 10U instead of HALLCOMID M-10 is prepared in the same ratios. The mixtures are then maintained at 25 °C for 1 day. Table 2 summarizes the results and shows that increasing the amide portion turns the blend into a liquid or paste, lowering its melting point and reducing the need for heating.

[0044] This preparation is repeated with other nonionic alkoxylates, which have high melting points, but keeping a 2:1 ratio between STEPOSOL MET-10U and the nonionic alkoxylates. The melting points of the subsequent blends are then measured by DSC (differential scanning calorimetry). The melting point of the nonionic alkoxylates with and without STEPOSOL MET- 10U are summarized in Table 3. 9 4930-1386-2932, v.1Attorney Docket No. 102-P0585PCT

[0045] Table 2 Sample Comp (b) Comp (a) Ratio (a):(b) Result 1 TSP-60 M-10 1:4 Solid d dMelting Point (°C) Melting Point (°C) without STEPOSOL MET- with STEPSOL MET-10U

[0047] Table 3 demonstrates that the melting point of highly alkoxylated nonionic surfactants is reduced, sometimes to below 25 °C, which facilitates handling when used as a blend instead of individually.

[0048] EXAMPLE B: BEHAVIOR OF DIALKYL ALKYL OR ALKENYL AMIDE (DAA) AND NONIONIC ETHOXYLATE BLENDS IN AQUEOUS FORMULATION – EFFECT OF DAA STRUCTURE, RATIO, AND TEMPERATURE 10 4930-1386-2932, v.1Attorney Docket No. 102-P0585PCT

[0049] The objective of this formulation behavior study is to determine what drives the haziness of the formulation so that the solvent can be easily separated for re-use. These results are shown in Tables 4, 5, 6, 7, 8, 9, 10 and 11. Testing was performed to demonstrate the advantage of metastable, hazy-opaque, and water thin formulations which constitute a sustainable plastic recycling formulation compared to clear aqueous formulations.

[0050] 2% of the surfactant blend, discussed in Example A, is used in an aqueous solution having 1 wt% of NaOH (50%) to mimic the strength of alkalinity for generally acceptable cleaning solutions in the recycling process. The formulations of HALLCOMID M-10 / MAKON TSP-60 and STEPOSOL MET-10U / MAKON TSP-60 mixtures at 80 – 85 °C are presented in Table 4. The table reflects the formulations after agitation with a vortex mixer for 30 seconds at 3000 rpm and then after sitting for 3 hours. 11 4930-1386-2932, v.1Attorney Docket No. 102-P0585PCT

[0051] Table 4

[0052] Mixtures at 80-85 °C Sample Comp (b) Comp (a) Ratio After 3 hrs after Result (a):(b) agitation agitation

[0053] Table 4 illustrates the formulations using either STEPOSOL MET-10U or HALLCOMID M-10 as a solvent exhibit the development of a clear formulation when the component (a) is less than the component (b). For example, when the ratio of component (a) & (b) is from 1:2 to 1:5, the formulation exhibits the stable clear phase. Although a clear cleaning solution can be easily applied to plastic materials, the recovery of the solvent phase after the cleaning process would be difficult by mechanical separation (e.g. centrifuge). The metastable formulation, especially when the component (a) is greater than the component (b), can also be used for the cleaning process. However, whereas the recovery of the component (a) or (b) is difficult for the clear cleaning solution, the metastable formulation exhibits the spontaneous separation of the components and thereby the spontaneous recovery. Interestingly, the separation of STEPOSOL MET-10U is faster 12 4930-1386-2932, v.1Attorney Docket No. 102-P0585PCT than HALLCOMID M-10. This indicates the advantage of MET-10U separation after the cleaning process.

[0054] The effect of temperature on the formulation behavior is further studied. Results are summarized in Table 5 and Table 6, which show the formulation behaviors at 70 – 75 °C and 60 – 65 °C respectively. Table 4, 5 and 6 indicate that a 20 °C difference does not significantly impact the boundary between clear / stable formulation and metastable formulation. However, for the metastable formulation at 2:1 ratio or above, the haziness becomes less noticeable, meaning the formulation becomes more stable and thereby less recovery.

[0055] Table 5

[0056] Mixtures at 70-75 °C Sample Comp (b) Comp (a) Ratio After 3 hrs after Result (a):(b) agitation agitation13 4930-1386-2932, v.1Attorney Docket No. 102-P0585PCT

[0057] Table 6

[0058] Mixtures at 60-65 °C Sample Comp (b) Comp (a) Ratio After 3 hrs after Result (a):(b) agitation agitation

[0059] Table 7 illustrates the impact of chain length on the formulations. It shows that a metastable formulation can be achieved even at 1:2 ratio of solvent and surfactant when the alkyl chain in the solvent increases. It should be noted that foaminess becomes noticeably increased when the formulation is clear for all formulations. The importance of the foaminess of formulation will be discussed further in Example C. 14 4930-1386-2932, v.1Attorney Docket No. 102-P0585PCT

[0060] Table 7

[0061] Mixtures at 80-85 °C Sample Comp (b) Comp (a) Ratio Result (a):(b)[ ] e e ec o ranc s ruc ure an empera ure s s own n ables 8 and 9 respectively. Compared to the result from Table 7, the results from Table 8 and 9 demonstrate that the effect of temperature reduction from 80 – 85 °C to 65 – 75 °C is insignificant to affect the boundary of clear / stable and metastable formulations. However, the formulation having HALLCOMID M-8 as a solvent starts to be clear at a 2:1 ratio, or even 4:1 ratio indicating the shorter chain amide is useful to be formulated as clear solutions rather than metastable solutions when the temperature is reduced. 15 4930-1386-2932, v.1Attorney Docket No. 102-P0585PCT

[0063] Table 8

[0064] Mixtures at 80-85 °C Sample Comp (b) Comp (a) Ratio Result (a):(b)

[0066] Mixtures at 65-75 °C Sample Comp (b) Comp (a) Ratio Result (a):(b)

[0067] The separation behavior of the formulations is observed after 12 hours as shown in Table 10. Table 10 demonstrates that the metastable formulations separate and form a supernatant top 16 4930-1386-2932, v.1Attorney Docket No. 102-P0585PCT layer. This result suggests that the top layer could be recovered via gravitational separation, potentially allowing for reuse of solvent and surfactant mixture.

[0068] Table 10

[0069] Mixtures at 65-75 °C Sample Comp (b) Comp (a) Ratio Result (a):(b) n n n n n

[0070] Table 11 summarizes the behavior of formulations having a 2:1 ratio of dimethyl dialkyl / dialkene amide and MAKON TSP-60, 2 wt% in 1 wt% NaOH (50%) aqueous solution at 17 4930-1386-2932, v.1Attorney Docket No. 102-P0585PCT 80 – 85 °C. Table 11 clearly demonstrates that those formulations having a 2:1 ratio of dimethyl dialkyl / dialkene amide and MAKON TSP-60 have a “metastable” characteristic behavior.

[0071] Table 11

[0072] Mixtures 2:1 ratio of dimethyl dialkyl / dialkene amide & TSP-60, 2 wt% in 1 wt% NaOH (50%) aqueous solution at 80-85 °C Sample Comp (b) Comp (a) Result 148 TSP-60 M-9 Opaque, metastable

[0073] EXAMPLE C: COMPARISON TO THE FORMULATION WITH GLYCOL ALKYL ETHER CHEMISTRY – FORMULATION BEHAVIOR AND PERFORMANCE

[0074] A formulation study is conducted with glycol alkyl ethers, which are typically used as cleaning components in the plastic recycling processes. Results are summarized in Tables 12 and 13 and illustrate the appearance of the formulation made by the 2:1 mixture of glycol alkyl ether and MAKON TSP-60 at two different temperatures. Tables 12 and 13 clearly demonstrate that most of the glycol ethers do not exhibit metastable formulations even at lower temperature. Rather, the formulations are single phase stable / clear solutions that are difficult to separate after the process. In Table 12, it is clearly seen that the stable and clear formulation with glycol alkyl ethers would provoke extensive foam, which normally reduces the operational effectiveness of the plastic recycling process.

[0075] Compared to formulations made by dialkyl or dialkene amides as demonstrated in Table 14, it is obvious that foaminess is significantly increased when the glycol alkyl ether is used in the formulation, whereas the metastable formulation generates much less foam. When formulations have 2 phases (e.g. metastable), we can expect less foaminess, as insoluble phases frequently act as foam suppressants. Since the amide solvents make the formulation more metastable, it is clear that the foaminess of formulations with the amide solvents is significantly decreased when compared to ones with glycol ethers. 18 4930-1386-2932, v.1Attorney Docket No. 102-P0585PCT

[0076] Table 12

[0077] Mixtures 2:1 ratio of glycol alkyl ethers and TSP-60

[0078] 80 – 85 °C Sample Solvent After 30 min. Result Agitation after19 4930-1386-2932, v.1Attorney Docket No. 102-P0585PCT

[0079] Table 13

[0080] Mixtures 2:1 ratio of glycol alkyl ethers and TSP-60

[0081] 60 °C Sample Solvent 30 min. Result after

[0082] Table 14

[0083] Comparison of the mixtures 2:1 ratio of (a) dialkyl or dialkene amides or (b) glycol alkyl ethers and TSP-60

[0084] 60 °C Sample Solvent After agitation Result20 4930-1386-2932, v.1Attorney Docket No. 102-P0585PCT

[0085] EXAMPLE D: EVALUATION OF DIFFERENT NONIONIC ALKOXYLATES IN BLEND

[0086] The cloud point of other nonionic alkoxylates used in the study is measured by adding 1 wt% nonionic alkoxylates into 2 wt% NaOH (50%). Measured cloud points are shown in Figure 1. It demonstrates that the cloud point of the nonionic alkoxylates in the presence of high NaOH concentration are above 80 °C.

[0087] The effect of nonionic alkoxylates is studied by replacing the MAKON TSP-60 with different nonionic ethoxylates or alkoxylates. Tables 15 and 16 demonstrate the formulation behavior when TDA-50 (tridecyl alcohol 50 EO) or UD-40 (undecyl alcohol 40EO) is used as a replacement of MAKON TSP-60, and Tables 17 and 18 demonstrate the formulation behavior when laureth-40 (lauryl alcohol 40EO), MAKON TD-50 (tridecyl alcohol alkoxylate), and castor oil – 40EO (Toximul 8242) are used.

[0088] Since all nonionic alkoxylates shown in Tables 15, 16, 17, and 18 have a cloud point above 80 °C in 2 wt% NaOH (50%) as seen in Figure 1, it is clear that the metastable observed behavior comes from the combination of the surfactant with dialkyl or diakenyl amides inducing a 2-phase metastable emulsion. The results of Example D are shown in Tables 15, 16, 17 and 18, and demonstrate that these additional nonionic ethoxylates or alkoxylates can be used to form metastable cleaning solutions with alkyl dialkyl or dialkene amides and that they can serve as successful replacements of MAKON TSP-60 without inducing clear formulation, in spite of their high cloud points (above 80 °C). 21 4930-1386-2932, v.1Attorney Docket No. 102-P0585PCT

[0089] Table 15

[0090] Mixtures - 2:1 ratio Comp (a) and Comp (b) at 80-85 °C, after agitation Sample Comp (b) Comp (a) Result 178 TSP-60 M-8 Opaque22 4930-1386-2932, v.1Attorney Docket No. 102-P0585PCT

[0091] Table 16

[0092] Mixtures - 2:1 ratio Comp (a) and Comp (b) at 65-75 °C, after agitation Sample Comp (b) Comp (a) Result 178 TSP-60 M-8 Clear23 4930-1386-2932, v.1Attorney Docket No. 102-P0585PCT

[0093] Table 17

[0094] Mixtures - 2:1 ratio Comp (a) and Comp (b) after agitation Sample Comp (b) Comp (a) Temperature, Result °C24 4930-1386-2932, v.1Attorney Docket No. 102-P0585PCT

[0095] Table 18

[0096] Mixtures - 2:1 ratio Comp (a) and Comp (b) at 80-85 °C Sample Component (b) Component After 1 hr Result (a) agitation After25 4930-1386-2932, v.1Attorney Docket No. 102-P0585PCT

[0097] EXAMPLE E: DETERMINATION OF THE RESIDUE ON PLASTIC MATERIALS AFTER CLEANING

[0098] Washing experiments are conducted using mixtures of dialkyl / dialkene amides as the solvent and MAKON TSP-60 or MAKON TD-50 as the surfactant. First, a combination of 5 wt% STEPOSOL MET-10U and varying amounts of surfactant are added in a 1 wt% NaOH (50%) solution. Disposed pieces of PET bottles are used to prepare plastic substrates. The plastic substrate is then washed with the recycling solutions containing different amounts of MAKON TSP-60 or MAKON TD-50 (from 0 to 1 wt%). The concentrations of STEPOSOL MET-10U and NaOH are fixed. The PET substrate is added to the recycling solution and the washing is conducted at 80 – 90 °C for 1 – 2 minutes under 500 rpm agitation (stirring). After washing, the PET substrate is then rinsed with DI water (heated to 40 °C) for 15 – 30 seconds. Figure 2 shows images of the PET substrates after cleaning. Figure 2 shows that the formulation leaves STEPOSOL MET-10U residue when 0.25 wt% of either surfactant is used. However, the formulation starts to show improved cleaning, without leaving solvent residue, above usage levels of 0.5 wt% Makon TSP- 60 and 1.0 wt% MAKON TD-50.

[0099] Using the mixture of solvent and MAKON TSP-60 (2:1 ratio), the washing experiment is conducted. The formulation is prepared by dissolving a 2:1 mixture of solvent and MAKON TSP- 60 into 1 wt% NaOH (50%) solution. The concentration of the mixture in the solution ranges from 2 wt% to 5 wt%. Precleaned plastic materials are used for the washing test; 5 g of precleaned substrate is used to solely study the redeposition behavior of cleaning solution. The plastic materials are added to the cleaning solution which has been preheated to the desired temperature. The plastic materials are washed with cleaning solution for 1 – 2 minutes under 500 rpm agitation (stirring). The temperature is controlled by using a jacketed beaker connected to a water bath. Figure 3 depicts the washing procedure.

[0100] After washing, the plastic chips are collected and rinsed with 25 °C DI water for 30 seconds. After the rinsing, the plastic chips are dried at ambient temperature for 1 day. The weight of the collected plastic chips is measured again. To calculate the percent of residue on the plastic from the cleaning solution, the dried chip weight before cleaning (X) is subtracted from the weight of the dried chip value after the cleaning procedure (Y), divided by the dried chip before the cleaning procedure (X) and multiplied by 100 or in other words [(Y-X) / X]*100. The washing experiment is conducted with several cleaning formulations having different solvents. Figures 4 26 4930-1386-2932, v.1Attorney Docket No. 102-P0585PCT and 5 show the experimental result. In Figures 4 and 5, the washing composition using only STEPOSOL MET-10U showed noticeable weight gain. This indicates the composition without co-surfactant such as MAKON TSP-60 would leave a significant amount of cleaning solvent on the plastic material. This residue of cleaning solvent would cause the quality issue of plastic recycling process. Increased usage of MAKON TSP-60 results in a reduction in deposition of STEPOSOL MET-10U solvent on to the PET substrates.

[0101] For dialkyl amides with different alkyl chain lengths, a 2:1 ratio of solvent to surfactant at a 2% usage level affords only minimal solvent deposition, excepting in the cases of where long chain—C16 or higher—amide solvents are used. It is surprising that a majority of the metastable recycling solutions do not leave the solvent residue after the cleaning process, given how easily the solvent can be separated for re-use. Although the recovery of the cleaning components from the clear / stable solutions would require an extra down-streaming process which requires more energy and cost, these metastable solutions can be easily recycled with spontaneous separation without the concern of residue formation during the processes. Finally, as demonstrated in previous Examples, the composition comprised with dialkyl / dialkene amide as a solvent provokes less foaming than the clear solution implying the metastable formulation is preferred for both recyclability and overall process efficiency.

[0102] Figure 6 shows the result of solvent residue findings that were obtained when glycol alkyl ethers were employed instead of the amide solvents. It demonstrates that a clear / stable solution using glycol ether can cause a significant weight gain of the plastic material. These data demonstrate that the use of glycol ethers in this formulation system drives incompatibility with PET, causing the swelling of the material at the test condition. This occurs whether or not the glycol-containing formulation is hazy or clear.

[0103] Table 19 summarizes the data obtained with a wide range of amides at two different temperatures. The results in Table 19 demonstrate the residue formation decreases with decreasing the temperature. It is important to note that the residue formation from the cleaning solution is a function of the selection of component (B). For example, for the same component (A), when fatty oil ethoxylates, CO-40 is used, the percent of residue becomes pronounced. The result means some metastable formulations formulated also could provoke an undesired deposition on the substrate and the outcome depends on the selection of component (A) & (B). 27 4930-1386-2932, v.1Attorney Docket No. 102-P0585PCT

[0104] Table 19 Temperature Dialkyl (or dialkene) amide Nonionic alkoxylate % of residue 65 °C MET-10U UD-40 0.00 00 17 26 04 00 19 41 01 .0 01 15 00 00 02 53 75 85 71 00 58 27 42 04 78 22 58 21 36 04 19 00 22 22 17 4328 4930-1386-2932, v.1Attorney Docket No. 102-P0585PCT

[0105] EXAMPLE F: CLEANING OF CONTAMINANTS ON DESIGNED PLASTIC SUBSTRATE

[0106] To evaluate the cleaning performance of the composition, a label removal experiment is conducted. The PET substrate is purchased from McMaster and a color label is applied to simulate labeled PET waste material. Some labels have been stored for at least 1 year to simulate the old and aged label on the plastic substrate. 2 wt% of the blend (2 / 1 solvent to Makon TSP-60) in 1 wt% NaOH (50 %) cleaning solution is made, and a 250 ml jacketed beaker is filled with 150 mL of cleaning solution. The solution is continuously stirred at 400 rpm. The colored label attached PET substrate is added into the cleaning solution and the cleaning is conducted for 2 minutes. The label is then rinsed with DI water at 25 °C for 15 – 30 seconds.

[0107] To estimate the cleaning performance, the scoring for cleaning is conducted as follows: 1- No impact of formulation on dye / ink removal; 2-Formulation showed minimal impact on cleaning as evidenced by small amount of color fading; 3-Formulation showed average impact on cleaning as evidence by small amount of dye / ink removal that resulted in areas of no dye / ink; 4-Formulation showed above average impact on cleaning, evidenced by removal of larger areas of dye / ink that resulted in white patches and / or removed lettering so that the symbol is no longer readable; 5- Formulation resulted in superior dye / ink removal as evidenced by significant dye removal that resulted in greater cleaning than scoring 1-4 and / or complete dye / ink removal.

[0108] Table 20 summarizes results of the cleaning test. The results demonstrate that the inventive cleaning composition offers improved removal of ink and adhesive on the label versus clear solutions with glycol ether as a solvent (e.g. PnB) which can be considered as incumbent formulation in the plastic cleaning process. The composition with glycol alkyl ether shows little cleaning activity on the label. 29 4930-1386-2932, v.1Attorney Docket No. 102-P0585PCT

[0109] Table 20

[0110] Cleaning of Label using the formulation containing - 2:1 ratio Comp (a) and Comp (b) in 1 wt% NaOH (50%) at 80-85 °C Comp (b) Comp (a) Cleaning Score

[0111] It is worth notingthat enhancement of cleaning was observed when shorter chain dialkyl amides are used. Further, it was found that both dimethyl and diethyl amides provide excellent cleaning. However, a reduction in cleaning performance was noted when the alkyl / alkenyl chain has more branched structure or if the length is too long (e.g. 2-Butyloctyl and Oleic). The introduction of a double bond in alkyl / alkene improves the cleaning performance (e.g. M-12 vs M-1225).These observations are also consistent with the cleaning test with aged label as shown in Table 21 (e.g. M-10 vs MET-10U). For both fresh and aged labels, the reduction of cleaning by increasing overall chain length was compensated by the introduction of double bond. This means, though the cleaning becomes reduced with increasing the overall chain length, the cleaning can be increased with the presence of double bond in carbon chain.

[0112] Aged labels are noticeably easier to clean with the composition of this work. The use of shorter alkyl chain, such as HALLCOMID M-8-10 and / or HALLCOMID M-9, does show the enhancement of cleaning compared to HALLCOMID M-10 or STEPOSOL MET-10U which is consistent with the observation in Table 20. However, some permanent color redeposition is observed when using these solvents as summarized in Table 22. This is not observed when using amides with C9 or higher alkyl or alkene chain length. 30 4930-1386-2932, v.1Attorney Docket No. 102-P0585PCT

[0113] Table 21

[0114] Cleaning of Label, aged, using the formulation containing - 2:1 ratio Comp (a) and Comp (b) in 1 wt% NaOH (50%) at 80-85 °C Comp (b) Comp (a) Cleaning Score

[0115] Table 22

[0116] Cleaning of Label, aged, using the formulation containing - 2:1 ratio Comp (a) and Comp (b) in 1 wt% NaOH (50%) at 80-85 °C Comp (b) Comp (a) Cleaning Color redeposition from Score label to substrate

[0117] Table 23 summarizes the results of the washing test using surfactants other than MAKON TSP-60 at 60-70 °C. Although lower temperatures result in a reduction of cleaning performance, the formulation's cleaning performance is acceptable given that the label is notably difficult to clean with existing technology. TOXIMUL 8242 (CO-40) was found to have the lowest performance. This result suggests that even when using the same solvent, the choice of nonionic alkoxylate is crucial for ensuring cleaning performance.

[0118] Various combinations of amides and nonionic alkoxylates are used for the extensive cleaning evaluation at two different temperatures as summarized in Table 23. 31 4930-1386-2932, v.1Attorney Docket No. 102-P0585PCT

[0119] Table 23 Experiment M-8 M-8-10 M-9 M-10 MET-10U M-12 M-1225 Temperature

[0120] EXAMPLE G: RECOVERY OF DIALKYL ALKYL OR ALKENE AMIDE AND NONIONIC ETHOXYLATE BLENDS AND REUSE

[0121] A solvent recovery study is conducted at two different temperatures. The formulation is stored at 60 and 80 °C respectively, both of which are below the cloud point of the surfactant, for 6 hours after 3000 rpm agitation for 20 sec. Separation is then observed over time. The volume of supernatant after the gravitational separation is used to estimate the recovered amount as the initial volume fraction of surfactant and solvent is known. Tables 24 and 25 summarize the solvent recovery at two different temperatures. 1φ means the separated recycling aid is homogenous and visually transparent even after supernatant is formed. 2φ means the separated recycling aid is metastable, optically opaque, even after supernatant is formed. At 60 °C, samples with a recovery of more than 10% are highlighted. At 80 °C, samples with a recovery of more than 20% vol% are highlighted. In general, lower solvent recovery is observed when the dimethyl amide alkyl chain is shorter than C8. Higher alkyl chain length generally exhibit improved recovery, likely due to the insolubility of the solvent. From C10 to C12, whether the double bond is present or not, an adequate amount of solvent recovery is observed, preferably greater than 10 wt.%. 32 4930-1386-2932, v.1Attorney Docket No. 102-P0585PCT

[0122] Table 24 at 60 °C UD-40 TDA-50 Laureth-40 TD-50 TSP-60 CO-40 M8 1φ, 0% 1φ, 0% 1φ, 0% 1φ, 0% % % % %

[0123] Table 25 at 80 °CUD-40 TDA-50 Laureth-40 TD-50 TSP-60 CO-40 M8 1φ 0% 1φ 0% 1φ 0% 1φ 0%

[0124] EXAMPLE H: COMPOSITION OF THE RECOVERED PLASTIC RECYCLING PROCESS AID

[0125] To estimate the recovered amount of surfactant and solvent, quantitative1H NMR is employed. First, the supernatant samples, separated from each formulation, were collected. The provided supernatant was homogenized on a vortex mixer. Immediately after homogenization, 40.0 – 50.0 mg of the material was transferred to a tared 1-dram vial via pipette. The mass added was recorded. Mesitylene (20.0 – 30.0 mg) was then added via pipette as an internal standard. The mass was recorded. It was observed that mesitylene and supernatant samples were not miscible 33 4930-1386-2932, v.1Attorney Docket No. 102-P0585PCT with one another. Perdeuterated methanol (CD3OD, 750 μL) was then added and the mixture was again homogenized on a vortex mixer. The subsequent sample was clear and colorless liquid. The sample was transferred to a 5 mm NMR tube. This procedure was followed for all 14 of the provided samples. In addition, a control containing just mesitylene and perdeuterated methanol was prepared.

[0126] In Quantitative1H NMR, a delay time of 20 s was utilized between each pulse to ensure complete proton relaxation. Following acquisition, the resulting spectra were referenced to CD2HOD at 3.31 ppm. Integrations were measured for the mesitylene and dimethylamide components. The following resonances were used for comparative purposes: a. Mesitylene i. Aromatic CH, three protons total, ~ 6.75 ppm ii. Methyl CH3, nine protons total, ~2.25 ppm b. Dimethylamide i. Amide CH3, three protons total, ~3.00 ppm ii. Amide CH3, three protons total, ~ 2.90 ppm iii. CH2 alpha to carbonyl, two protons total, ~2.34 ppm

[0127] Using the integrations, a molar ratio of mesitylene standard to dimethylamide was established. From this ratio, the amount of dimethyl amide present in the solution was determined. To be specific, since the mass of mesitylene added is known, the moles of mesitylene, and (using the molar ratio) the moles of dimethylamide in the sample were calculated. Quantities of dimethylamide in each of the samples were then determined using the molecular weights of M-10, M-10U, M-12, and M-1214. In the case of M-1224, the effective weight was estimated by assuming that the material was 50% C12 and 50% C14. The percentage of dimethyl amide (by mass) in each supernatant was then determined using the original sample mass. The experimental results are collected in Table 26. 34 4930-1386-2932, v.1Attorney Docket No. 102-P0585PCT

[0128] Table 26 Sample Analyte Percent Amide in Sample (%) 1 M10 / TD50 75.13

[0129] The result in Table 26 clearly shows more than 50 wt % of solvent were recovered in the mixture of supernatant. Theoretical percentages of amide is ~66% as a 2:1 ratio of solvent and nonionic alkoxylate is used. All mixtures except MET-10U / Toximul 8242 show a higher value of recovery than theoretical value (i.e. 66% or more). The fact that the recovered amides and nonionic alkoxylates ratio is close to the original ratio indicates that the supernatant mixture can be re-used itself without extensive separation process to separate solvent or alkoxylates from the mixture. 35 4930-1386-2932, v.1

Claims

Attorney Docket No. 102-P0585PCT We claim:

1. A plastic recycling process aid comprising a composition comprising component (a) and component (b), wherein component (a) is at least one of an alkyl dialkylamide and alkene dialkylamide; and component (b) is selected from at least one nonionic alkoxylate, wherein the ratio of component (a) to component (b) is 20 / 1 to 1 / 20, wherein the composition forms a metastable composition upon mixing with an aqueous solution.

2. The plastic recycling process aid of claim 1 wherein the ratio is 10 / 1 to 1 / 5.

3. The plastic recycling process aid of claim 2 wherein the ratio is 5 / 1 to 1 / 1.

4. The plastic recycling process aid of claim 1 wherein the component (a) is selected from N,N-dimethyloctanamide (N,N-dimethylcaprylamide), N,N-dimethyl-decanamide (N, N- dimethylcapramide), N,N-dimethylnonanamide, N,N-demethyldecanamide, N, N-dimethyl 9-decenamide, N,N-dimethyldodecanamide, N,N-dimethyldodecanamide, (N,N- dimethyllauramide), N,N-dimethyltetradecanamide, (N,N-dimethylmyristamide), N, N- dimethyldodec-9-enamide, 2-butyloctyl dimethylamide, N,N-lauryl diethylamide, N,N- oleic dimethylamide, or mixtures thereof.

5. The plastic recycling process aid of claim 1 wherein component (b) is selected from an alkyl phenol ethoxylate, a fatty oil ethoxylate, an alcohol alkoxylate, an alcohol ethoxylate or a mixture thereof.

6. The plastic recycling process aid of claim 5 wherein component (b) is selected from an aralkylated phenol ethoxylate, an ethoxylated C11 – C14 alcohol, an ethoxylated, propoxylated, branched C11-C14alcohol, an ethoxylated castor oil, or mixtures thereof.

7. The plastic recycling process aid of claim 6 wherein component (b) is selected from the aralkylated phenol ethoxylate, an ethoxylated, branched C11alcohol, an ethoxylated 36 4930-1386-2932, v.1Attorney Docket No. 102-P0585PCT branched C12-C14lauryl alcohol, an ethoxylated, propoxylated branched C13alcohol, the ethoxylated castor oil or mixtures thereof.

8. The plastic recycling process aid of claim 1 where component (a) is selected from a C8– C18 dimethylamide having a linear or branched structure in the alkyl or alkene chain.

9. The plastic recycling process aid of claim 8 where component (a) is selected from a C10- C14 alkyl or alkene dimethylamide.

10. The plastic recycling process aid of claim 6 wherein component b) is selected from an aralkylated phenol ethoxylate having an average of 8 to 70 EO, an ethoxylated branched C11 alcohol having an average of 20 to 50 EO, an ethoxylated, branched C13 alcohol having an average of 30 to 60 EO, an ethoxylated C12-14 lauryl alcohol having an average of 20 to 50 EO, an ethoxylated castor oil having an average of 20 to 50 EO or mixtures thereof.

11. The plastic recycling process aid of claim 1 wherein component (a) is present in an amount of 50.0 to 92.0 wt% and component (b) is present in an amount of 8.0 to 50.0 wt%, based on the total weight of the plastic recycling process aid.

12. The plastic recycling process aid of claim 11 wherein component (a) is present in the amount of 50.0 to 81.0 wt% and component (b) is present in the amount of 19.0 to 50.0 wt.%, based on the total weight of the plastic recycling process aid.

13. The plastic recycling process aid of claim 12 wherein component (a) is present in the amount of 60.0 to 70.0 wt% and component (b) is present in the amount of 30.0 to 40.0 wt%, based on the total weight of the plastic recycling process aid.

14. A process comprising administering the plastic recycling process aid of claim 1 into a plastic recycling process. 37 4930-1386-2932, v.1Attorney Docket No. 102-P0585PCT 15. A process for removing contaminants from plastic comprising: - contacting the plastic recycling process aid of claim 1 with an aqueous composition, thereby forming a metastable wash solution; - contacting plastic comprising the contaminants with the metastable wash solution, thereby forming a wash slurry; - separating the wash slurry, thereby forming a separated plastic and a separated process aid, wherein the separated and washed plastic has a residue of 0 to 1.0% based on the weight of the separated and washed plastic, and wherein the contaminant level of the separated plastic is at least 20% lower than the plastic prior to contact with the metastable plastic recycling process aid, based on the total weight of the separated plastic.

16. The process of claim 15 further comprising: - demulsifying the separated process aid thereby forming a demulsified stream; and - separating the demulsified stream into a first separated stream containing greater than 50 wt% of component (a) and a second separated stream containing greater than 30 wt% of component (b).

17. The process of claim 16 wherein a weight ratio of plastic recycling process aid to plastic in the contacting step is 8 / 1 to 12 / 1.

18. A metastable wash solution comprising: - 95.0 to 99.5 wt% of an aqueous composition; and - 0.5 to 5.0 wt% of the plastic recycling process aid of claim 1.

19. The wash solution of claim 19 wherein the aqueous composition is alkaline.

20. The wash solution of claim 19 wherein the ratio of component (a) / component (b) is 2:1 to 1:

5. 38 4930-1386-2932, v.1Attorney Docket No. 102-P0585PCT 21. The wash solution of claim 19 wherein the aqueous composition is present in an amount from 97.0 to 99.0 wt.% and the plastic recycling aid is present in an of 1.0 to 3.0 wt.%.

22. The wash solution of claim 30 further comprising NaOH.

23. A process comprising cleaning recycled plastic in a plastic recycling process with the wash solution of claim 19. 39 4930-1386-2932, v.1

Images