DESC:FIELD
The present disclosure relates to a process for the separation of polymer layers in multilayer packaging films.
DEFINITION
As used in the present disclosure, the following term is generally intended to have the meaning as set forth below, except to the extent that the context in which they are used to indicate otherwise.
Anti-solvent: The term “Anti-solvent” refers to a solvent in which the compound is not soluble completely or is less soluble.
BACKGROUND
The background information herein below relates to the present disclosure but is not necessarily prior art.
Multilayer packaging films are difficult to recycle by using conventional polymer recycling technologies such as mechanical recycling, due to the fact that the different layers are chemically compatible with each other. Similarly, the blister packs which are commonly used for unit dose packaging of pharmaceutical tablets, capsules, and the like, are made up of multilayer laminates, wherein different types of polymer layers and aluminium foil are sealed together with adhesives. Hence, recycling of the blister packs through conventional methods is not possible as the multilayer laminates are required to be deconstructed into their constituent resins before being processed.
Conventionally the multi-layered film contains polymer layers including polyester (PET), polypropylene (PP), and polyethylene (PE) as main components, and an aluminum layer. The layer of polypropylene and polyethylene are separated from the polyester layer according to their specific gravity, and polypropylene and polyethylene are extracted from the separated polyester layer using an organic fluid medium in order to increase the purity of polyester.
Further, the multilayer films can be separated by solvent-targeted recovery and precipitation (STRAP) process. Deconstruction of multilayer films into their constituent resins is done by using a series of solvent washes that are guided by thermodynamic calculations of polymer solubility.
However, the conventional methods for separating the polymer layers in the multilayer films are associated with drawbacks such as use of multiple organic fluid mediums and hazardous reagents, more number of steps, more quantity of fluid mediums and the like.
There is, therefore, felt a need to develop a process for the separation of polymer layers in multilayer packaging films that mitigates the drawbacks mentioned herein above or at least provides a useful alternative.
OBJECTS
Some of the objects of the present disclosure, which at least one embodiment herein satisfies, are as follows.
It is an object of the present disclosure to ameliorate one or more problems of the background or to at least provide a useful alternative.
An object of the present disclosure is to provide a process for the separation of polymer layers in multilayer packaging films.
Another object of the present disclosure is to provide a simple, economic and an environment friendly process for the separation of polymer layers in multilayer packaging films.
Still another object of the present disclosure is to provide a process for the separation of polymer layers in multilayer packaging films that requires minimum number of steps.
Yet another object of the present disclosure is to provide a process for the separation of polymer layers in multilayer packaging films that requires minimum usage of a fluid medium.
Still another object of the present disclosure is to provide a process for the separation of polymer layers in multilayer packaging films that avoids the usage of multi solvent and anti-solvents in the separation process.
Other objects and advantages of the present disclosure will be more apparent from the following description, which is not intended to limit the scope of the present disclosure.
SUMMARY
The present disclosure relates to a process for the separation of polymer layers in multilayer packaging films. The process comprises the following steps:
i) treating the multilayer packaging films with a solution of alkali metal salt of an aliphatic amino acid and optionally, at least one surfactant at a first predetermined temperature for a first predetermined time period to obtain at least two separated polymer layers; and
ii) optionally, treating the separated polymer layers with a fluid medium at a second predetermined temperature for a second predetermined time period to obtain further separated polymer layers.
In an embodiment of the present disclosure, the multilayer packaging film is selected from the group consisting of multilayer structure and multimaterial structure.
In an embodiment of the present disclosure, the multimaterial structure comprises at least one metal layer and at least one polymer layer.
In an embodiment of the present disclosure, the metal layer is aluminium layer.
In an embodiment of the present disclosure, the multilayer structure comprises at least two polymer layers.
In an embodiment of the present disclosure, the at least two polymer layers are same.
In an embodiment of the present disclosure, the at least two polymer layers are different.
In an embodiment of the present disclosure, the polymer layer is at least one selected from the group consisting of polypropylene (PP), polyethylene (PE), polyvinyl chloride (PVC), polyamide, polyethylene terephthalate (PET) and polyvinylidene chloride (PVDC).
In an embodiment of the present disclosure, the alkali metal salt of the alkali metal salt of the aliphatic amino acid (separating medium) is a sodium salt of aliphatic amino acid.
In an embodiment of the present disclosure, the sodium salt of aliphatic amino acid is sodium salt of 6-amino caproic acid.
In an embodiment of the present disclosure, the mass by volume ratio of the multilayer packaging films to the solution of alkali metal salt of an aliphatic amino acid is in the range of 1:40 to 1:120.
In an embodiment of the present disclosure, the solution of the alkali metal salt of the aliphatic amino acid comprises the alkali metal salt of an aliphatic amino acid, and water.
In an embodiment of the present disclosure, a concentration of the alkali metal salt of the aliphatic amino acid in the solution is in the range of 2% to 20%.
In an embodiment of the present disclosure, the surfactant is a non-ionic surfactant.
In an embodiment of the present disclosure, the non-ionic surfactant is selected from the group consisting of fatty alcohol ethoxylate, fatty alkanolamides, and amine oxides.
In an embodiment of the present disclosure, the fatty alcohol ethoxylate is selected from the group consisting of isotridecanol ethoxylate, fatty acid alkoxylate, and alkyl phenol ethoxylate.
In an embodiment of the present disclosure, the first predetermined temperature is in the range of 40 °C to 150 °C.
In an embodiment of the present disclosure, the first predetermined time period is in the range of 2 hours to 20 hours.
In an embodiment of the present disclosure, the fluid medium is selected from the group consisting of xylenes, chlorobenzene and ethyl benzene.
In an embodiment of the present disclosure, the second predetermined temperature is in the range of 100 °C to 200 °C.
In an embodiment of the present disclosure, the second predetermined time period is in the range of 30 minutes to 400 minutes.
BRIEF DESCRIPTION OF THE ACCOMPANYING DRAWING
The present disclosure will now be described with the help of the accompanying drawing, in which:
Figure 1 illustrates a schematic representation of the complete separation of multilayer packaging films achieved using RELSOLVE and xylene treatments in accordance with the experiment 1 of the present disclosure;
Figure 2 illustrates a schematic representation of the separation process of multilayer packaging material using RELSOLVE and surfactant of VM1 in accordance with the experiment 2 of the present disclosure;
Figure 3 illustrates the packaging structure of the multilayer packaging film structure of VM1 in accordance with the present disclosure;
Figure 4 illustrates a schematic representation of the layer separation process of VM2 in accordance with the experiment 4 of the present disclosure;
Figure 5 illustrates the packaging structure of the multilayer packaging film of VM2 in accordance with the present disclosure;
Figure 6 illustrates the structure of the aluminium–polymer blister pack of the pharmaceutical tablet 1 in accordance with the experiment 5 of the present disclosure;
Figure 7 illustrates the packaging structure of the blister pack of the pharmaceutical tablet 2 in accordance with the experiment 6 of the present disclosure;
Figure 8 illustrates the packaging structure of the Al-Al-3 blister pack of pharmaceutical tablet 3 in accordance with the experiment 8 of the present disclosure;
Figure 9 illustrates the packaging structure of the Al-Al-4 blister pack of pharmaceutical tablet 4 in accordance with the experiment 9 of the present disclosure;
Figure 10 illustrates the FTIR spectrum wherein (a) confirm the presence of PET, (b) confirms the presence of LDPE, (c) confirms the presence of LLDPE and (d) confirms the presence of PET in accordance with the present disclosure; and
Figure 11 illustrates the DSC graphs wherein (a) confirms the presence of PET, (b) confirms the presence of LDPE and (c) confirms the presence of LLDPE in accordance with the present disclosure.
LIST OF REFERENCE NUMERALS
REFERENCE NO. REFERENCE
a Cut pieces of multilayer film
b RELSOLVE 5% in DM water, 50 mL
c RELSOLVE 5%+nonionic surfactant (10%)
1 Upper printed layer (PET/LDPE)
2 Inner transparent layer (PET/LLDPE)
3 Aluminium dissolution (aluminium layer)
4 Upper layer (PET in VM1 & PP in VM2)
5 Printed layer (LDPE)
6 Transparent layer (PET)
7 White precipitate (LLDPE)
Al-P-1 Aluminium-polymer (Pharmaceutical tablet 1)
Al-P-2 Aluminium-polymer (Pharmaceutical tablet 2)
Al-Al-3 Aluminium-Aluminium (Pharmaceutical tablet 3)
Al-Al-4 Aluminium- Aluminium (Pharmaceutical tablet 4)
I Al layer as lid
II PVC blister layer
III PVC film
IV Rigid PVC layer
V Polyamide layer
VI Aluminium layer
DETAILED DESCRIPTION
The present disclosure relates to a process for the separation of polymer layers in multilayer packaging films.
Embodiments, of the present disclosure, will now be described with reference to the accompanying drawing.
Embodiments are provided so as to thoroughly and fully convey the scope of the present disclosure to the person skilled in the art. Numerous details are set forth, relating to specific components, and methods, to provide a complete understanding of embodiments of the present disclosure. It will be apparent to the person skilled in the art that the details provided in the embodiments should not be construed to limit the scope of the present disclosure. In some embodiments, well-known processes, well-known apparatus structures, and well-known techniques are not described in detail.
The terminology used, in the present disclosure, is only for the purpose of explaining a particular embodiment and such terminology shall not be considered to limit the scope of the present disclosure. As used in the present disclosure, the forms "a,” "an," and "the" may be intended to include the plural forms as well, unless the context clearly suggests otherwise. The terms "comprises," "comprising," “including,” and “having,” are open ended transitional phrases and therefore specify the presence of stated features, integers, steps, operations, elements, modules, units and/or components, but do not forbid the presence or addition of one or more other features, integers, steps, operations, elements, components, and/or groups thereof. The particular order of steps disclosed in the method and process of the present disclosure is not to be construed as necessarily requiring their performance as described or illustrated. It is also to be understood that additional or alternative steps may be employed.
As used herein, the term "and/or" includes any and all combinations of one or more of the associated listed elements.
The terms first, second, third, etc., should not be construed to limit the scope of the present disclosure as the aforementioned terms may be only used to distinguish one element, component, region, layer or section from another component, region, layer or section. Terms such as first, second, third etc., when used herein do not imply a specific sequence or order unless clearly suggested by the present disclosure.
Multilayer packaging films are difficult to recycle by using conventional polymer recycling technologies such as mechanical recycling, due to the fact that the different layers are not chemically incompatible with each other. Similarly, the blister packs which are commonly used for unit dose packaging of pharmaceutical tablets, capsules, and the like, are made up of multilayer laminates, wherein different types of polymer layers and aluminium foil are sealed together with adhesives. Hence, recycling of the blister packs through conventional methods is not possible as the multilayer laminates are required to be deconstructed into their constituent resins before being processed.
Conventionally the multi-layered film contains polymer layers including polyester (PET), polypropylene (PP), and polyethylene (PE) as main components, and an aluminum layer. The layer of polypropylene and polyethylene are separated from the polyester layer according to their specific gravity, and polypropylene and polyethylene are extracted from the separated polyester layer using an organic fluid medium in order to increase the purity of polyester.
Further, the multilayer films can be separated by solvent-targeted recovery and precipitation (STRAP process). Deconstruction of multilayer films into their constituent resins is done by using a series of solvent washes that are guided by thermodynamic calculations of polymer solubility.
However, the conventional methods for separating the polymer layers in the multilayer films are associated with drawbacks such as use of multiple organic fluid mediums and hazardous reagents, more number of steps, more quantity of fluid mediums and the like.
The present disclosure provides a process for the separation of polymer layers in multilayer packaging films.
In accordance with the present disclosure, the process for the separation of polymer layers in multilayer packaging films comprises the following steps:
i) treating the multilayer packaging films with a solution of alkali metal salt of an aliphatic amino acid and optionally, at least one surfactant at a first predetermined temperature for a first predetermined time period to obtain at least two separated polymer layers; and
ii) Optionally, treating the separated polymer layers with a fluid medium at a second predetermined temperature for a second predetermined time period to obtain further separated polymer layers.
The process is described in detail.
In a first step, the multilayer packaging films are treated with a solution of alkali metal salt of an aliphatic amino acid and optionally, at least one surfactant at a first predetermined temperature for a first predetermined time period to obtain at least two separated polymer layers.
In an embodiment of the present disclosure, the multilayer packaging film is treated with the solution of alkali metal salt of an amino acid without using the surfactant.
In another embodiment of the present disclosure, the multilayer packaging film is treated with the solution of alkali metal salt of an amino acid along with at least one surfactant.
In an embodiment of the present disclosure, the multilayer packaging film is selected from the group consisting of multilayer structure and multimaterial structure. In an exemplary embodiment of the present disclosure, the multilayer packaging film is a multilayer structure. In another exemplary embodiment of the present disclosure, the multilayer packaging film is a multimaterial structure.
In an embodiment of the present disclosure, the multimaterial structure comprises at least one metal layer and at least one polymer layer.
In an embodiment of the present disclosure, the metal layer is an aluminium layer.
The aluminium layer is in the form of aluminum foil or aluminium powder.
The multimaterial structure comprising at least one metal layer and at least one polymer layer is a blister pack.
In an embodiment of the present disclosure, multilayer structure comprises at least two polymer layers.
In an embodiment of the present disclosure, the at least two polymer layers are same.
In another embodiment of the present disclosure, the at least two polymer layers are different.
In an embodiment of the present disclosure, the polymer layer is at least one selected from the group consisting of polypropylene (PP), polyethylene (PE), polyvinyl chloride (PVC), polyamide, polyethylene terephthalate (PET) and polyvinylidene chloride (PVDC). In an exemplary embodiment of the present disclosure, the polymer is polypropylene (PP). In another exemplary embodiment of the present disclosure, the polymer is polyethylene (PE). Still, in another exemplary embodiment of the present disclosure, the polymer is polyethylene (PE). Yet, in another exemplary embodiment of the present disclosure, the polymer is polyvinyl chloride (PVC). Still further, in another exemplary embodiment of the present disclosure, the polymer is polyamide. Still furthermore, in another exemplary embodiment of the present disclosure, the polymer is polyethylene terephthalate (PET). Yet in another exemplary embodiment of the present disclosure, the polymer is polyvinylidene chloride (PVDC).
In an embodiment of the present disclosure, the alkali metal salt of the aliphatic amino acid (separating medium) is sodium salt of aliphatic amino acid.
In an embodiment of the present disclosure, the sodium salt of aliphatic amino acid is sodium salt of 6-amino caproic acid.
Sodium salt of 6-amino caproic acid (hereinafter referred as ‘RELSOLVE’) is represented as the following structure:

Sodium salt of 6-amino caproic acid (separating medium) is capable of separating the polymer layers of the multilayer packaging material and blister packs by dissolution of the adhesives used to bond the layers resulting in the separation of layers.
The separating medium also dissolves aluminium layer and subsequent precipitation as greying sodium aluminate particles. Thus, the separation of layers from the multi-layer, multimaterial structured packaging films and blister packs is achieved. Efficient separation of layers is observed by using the separating medium of the present disclosure in all types of blister packs and multilayer packaging films.
In an embodiment acetone is used as anti-solvent to ensure complete precipitation.
In an embodiment of the present disclosure, a mass by volume ratio of the multilayer packaging films to the solution of alkali metal salt of an aliphatic amino acid is in the range of 1:40 to 1:120. In an exemplary embodiment of the present disclosure, the mass by volume ratio of the multilayer packaging films to the solution of alkali metal salt of an aliphatic amino acid is 1:50. In another exemplary embodiment of the present disclosure, the mass by volume ratio of the multilayer packaging films to the solution of alkali metal salt of an aliphatic amino acid is 1:44.3.
In an embodiment, the solution of the alkali metal salt of an aliphatic amino acid is prepared by dissolving a predetermined amount of the alkali metal salt of an aliphatic amino acid in a predetermined amount of water.
In an embodiment of the present disclosure, the solution of the alkali metal salt of an aliphatic amino acid comprises the alkali metal salt of an aliphatic amino acid, water and optionally the surfactant.
In an embodiment of the present disclosure, a concentration of the alkali metal salt of an aliphatic amino acid in the solution is in the range of 2% to 20%. In an embodiment of the present disclosure, a concentration of the alkali metal salt of an aliphatic amino acid in the solution is in the range of 5% to 10%. In an exemplary embodiment of the present disclosure, a concentration of the alkali metal salt of an aliphatic amino acid in the solution is 5%.
In an embodiment of the present disclosure, the surfactant is a non-ionic surfactant.
In an embodiment of the present disclosure, the non-ionic surfactant is selected from the group consisting of fatty alcohol ethoxylate, fatty alkanolamides, and amine oxides.
In an embodiment of the present disclosure, the fatty alcohol ethoxylate is selected from the group consisting of isotridecanol ethoxylate, fatty acid alkoxylate, and alkyl phenol ethoxylate. In an exemplary embodiment of the present disclosure, the fatty alcohol ethoxylate is isotridecanol ethoxylate.
Usage of surfactant along with separating medium increases the efficiency of separation by separating more number of layers in multilayer films and nearly 40% to 50 % reduction in the time of separation.
In an embodiment of the present disclosure, the first predetermined temperature is in the range of 40 °C to 150 °C. In an exemplary embodiment of the present disclosure, the first predetermined temperature is 60 °C.
In an embodiment of the present disclosure, the first predetermined time period is in the range of 2 hours to 20 hours. In an exemplary embodiment of the present disclosure, the first predetermined time period is 12 hours.
In an embodiment of the present disclosure, the multilayer packaging films are treated with a solution of alkali metal salt of an aliphatic amino acid and optionally, at least one surfactant at a first predetermined temperature for a first predetermined time period to obtain at least two separated polymer layers and is refluxed in a flask fitted with a condenser at the first predetermined temperature under stirring.
In a second step, optionally, the separated polymer layers are treated with a fluid medium at a second predetermined temperature for a second predetermined time period to obtain further separated layers.
In an embodiment of the present disclosure, the fluid medium is selected from the group consisting xylene, chlorobenzene, and ethyl benzene. In an exemplary embodiment of the present disclosure, the fluid medium is xylene.
In an embodiment of the present disclosure, the second predetermined temperature is in the range of 100 °C to 200 °C. In an exemplary embodiment of the present disclosure, the second predetermined temperature is 125 °C.
In an embodiment of the present disclosure, the second predetermined time period is in the range of 30 minutes to 400 minutes. In an exemplary embodiment of the present disclosure, the second predetermined time period is 60 minutes.
In an embodiment of the present disclosure, the separated polymer layers are treated with a fluid medium at a second predetermined temperature for a second predetermined time period to obtain further separated layers in which the polymer layer bonded to the aluminum layer is softened and disintegrated with separation of the metal layer.
In another embodiment of the present disclosure, the disintegration of the metal layer is avoided by further treating the remaining metal layer bonded with the polymer layer with the alkali metal salt of an aliphatic amino acid.
In accordance with the present disclosure, the layer separation take place by treating multilayer packaging films with a solution of alkali metal salt of an aliphatic amino acid and optionally, at least one surfactant. The sodium salt of 6-amino caproic acid on hydrolysis forms sodium hydroxide (NaOH) and aminohexanoic acid. The NaOH formed reacts with aluminium in the multilayer film and forms sodium aluminate which is highly soluble in aqueous medium. Further, dissolution of tie layers/adhesives between the layers causes separation of layers.

In the process of the present disclosure, the separating medium (sodium salt of 6-amino caproic acid) (RELSOLVE) is capable of separating the polymer layers of the multilayer packaging material and blister packs by dissolution of the adhesives (used to bond the layers) resulting in the separation of layers. The separating medium RELSOLVE also dissolves the aluminium layer and subsequent precipitation as greying sodium aluminate particles takes place.
The process of the present disclosure has the following advantages:
• the separating medium i.e. the sodium salt of 6-amino caproic acid efficiently separates the polymer layers in the multilayered, multimaterial packaging films and blister packs aiding the recycling of the separated polymers;
• employs only one separating medium i.e. the sodium salt of amino caproic acid (RELSOLVE)and only one organic fluid medium;
• avoids the usage of multiple fluid media and anti-fluid media in the separation process, thus making the process more eco-friendly and sustainable.
• enables complete separation of the layers in single to maximum three steps for multilayered, multimaterial structures;
• the blister packs of aluminium-polymer type are separated in a simple single step process;
• the layer separation of blister pack can be carried out without requirement of further organic fluid medium treatments; and
• the multilayer packaging structures of almost all polymers are separated by using the process of the present disclosure.
The foregoing description of the embodiments has been provided for purposes of illustration and not intended to limit the scope of the present disclosure. Individual components of a particular embodiment are generally not limited to that particular embodiment but are interchangeable. Such variations are not to be regarded as a departure from the present disclosure, and all such modifications are considered to be within the scope of the present disclosure.
The present disclosure is further described in light of the following experiments which are set forth for illustration purposes only and not to be construed for limiting the scope of the disclosure. The following experiments can be scaled up to industrial/commercial scale and the results obtained can be extrapolated to industrial scale.
EXPERIMENTAL DETAILS
Experiment No 1: Process for the separation of polymer layers in multilayer packaging films (VMI) without using surfactants in accordance with the present disclosure.
Step 1: Layer separation in multilayer packaging material using RELSOLVE (sodium salt of 6-amino caproic acid) (separating medium)
Vendor material -1 (VM1) was used as the multilayer packaging film.
1.13 g of small pieces of multilayer film of VM1 was treated with 50 ml of 5% RELSOLVE solution in DM water at 60°C with stirring by using a magnetic stirrer. Separation of layers was observed after 12 hours with dissolution of aluminium layer. Two layers the upper/top printed layer and inside/inner transparent layer got separated. The layers were washed with water and kept for atmospheric drying.
Step 2: Fluid medium treatment
The fluid medium treatment was carried out for upper/top printed layer for further separation. The top layer was treated with xylene at 125 °C for 1 hour. Separation of the top layer into two layers was observed wherein one layer was printed layer and other was coloured layer. The separated layers were washed with water and dried.
Similarly, the inner transparent layer was also treated with xylene at 125°C for 4 hours to obtain a treated transparent layer. The treated transparent layer was separated by filtration to obtain a filtrate. 50 ml of acetone was added to the filtrate to obtain a white precipitate of another separated layer.
Figure 1 illustrates the complete separation of multilayer packaging film materials by using RELSOLVE and xylene treatments.
Table 1 illustrates the mass balance of the layer separation process of VM1, without usage of surfactant.
Table 1: Mass balance of the layer separation process of VM1, without usage of surfactant.
Multilayer packaging film VM1 Without surfactant (Step 1)
Conditions
Weight of sample 1.13 g
Concentration of alkali metal salt of an amino acid (separating medium) 5% RELSOLVE
Volume of a solution of alkali metal salt of an aliphatic amino acid taken 50ml
Temperature 60°C
Duration 12 h
Calculations
Volume of solution of alkali metal salt remains after separation process 43ml
Weight of separated Transparent layer 0.62 g
Weight of top printed layer 0.40 g
Weight of aluminium layer:
Weight of sample taken – total weight of separated polymer layer 1.13-1.02 = 0.10 g
Separation of top printed layer VM 1 (organic fluid medium treatment step 2)
Conditions
Weight of sample (separated top printed layer) 0.40 g
Fluid medium Xylene
Volume of fluid medium taken 50ml
Temperature 125°C
Duration 1 h
Calculations
Weight of printed polymer layer after drying 0.14 g
Weight of separated top transparent layer 0.25 g
Volume of fluid medium remains after separation process 45 ml
Separation of Transparent layer VM1 (organic fluid medium treatment step 2)
Conditions
Weight of sample (separated transparent layer) 0.62 g
Fluid medium Xylene
Volume of fluid medium taken 50ml
Temperature 125°C
Duration 4 h
Fluid medium Used for Polymer PPT Acetone (50ml)
Calculations
Weight of dissolved polymer layer after drying 0.03 g
Volume of fluid medium remains after separation process 45 ml
Weight of separated Transparent layer 0.59 g
Experiment No 2: Process for the separation of polymer layers in multilayer packaging films (VMI) by using surfactants in accordance with the present disclosure.
Step 1: Layer separation in multilayer packaging material using RELSOLVE (sodium salt of 6-amino caproic acid) (separating medium) and a surfactant.
1.1 g of small pieces of the multilayer film VM1 was treated with 50 mL solution of 10% surfactant and 5 % RELSOLVE in DM water for 6 hours at 60 °C. Separation of 3 polymer layers (upper layer, printed layer and inner transparent layer) with the dissolution of aluminium layer was observed in 6 hours.
Step 2: Treatment with fluid medium.
The inner transparent layer was treated with xylene at 125°C for 1 hour and the transparent layer was separated by filtration at hot condition to obtain separated transparent layers and a filtrate comprising white precipitate. The white precipitate was cooled and separated. The separated transparent layers were washed with water and dried.
Figure 2 illustrates the process for the separation of polymer layers in multilayer packaging films by using surfactants in accordance with the present disclosure.
Table 2 illustrates the mass balance for the layer separation process along with the number of repeat usages of the same solution of alkali metal salt of an aliphatic amino acid (separating medium) for layer separation process.
Table 2: Mass balance and number of usages of the separating medium of VM1 with surfactant.
Multilayer film (VM1) With surfactant (Step 1)
Reaction conditions (Step 1) I Separation II Separation III Separation
Weight of sample 1.1 g 1.0 g 1.0 g
Concentration of alkali metal salt of an aliphatic amino acid and surfactant in the solution. 5% RELSOLVE & 10% Surfactant 5% RELSOLVE & 10% Surfactant 5% RELSOLVE & 10% Surfactant
Volume of Solution of alkali metal salt of an aliphatic amino acid taken 50 mL 46 mL (filtrate of I separation) 40 mL (filtrate of II separation)
Temperature 60°C 60°C 60°C
Duration 5h 5h 5h
Mass balance
Weight of sample 1.1 g 1.0 g 1.0 g
Weight of top layer (green colour transparent layer) 0.23 g 0.13 0.10
Weight of printed layer 0.17 g 0.09 0.07
Weight of inner transparent layer 0.58 g 0.63 0.49
Weight of aluminium layer:
Weight of sample taken – total weight of separated polymer layer 1.1 – 0.98 = 0.12 g 1.0 – 0.85 = 0.15 g 1.0 – 0.66 = 0.34 g
Unseparated Al layer 0 g 0.2 g 0.3
Total mass 1.1 g 1.2 g 1.3 g
Mass balance - Layer separation of Inner transparent layer using xylene (Step 2)
Reaction conditions
Weight of sample (Inner transparent layer) 0.58 g
Fluid medium Xylene
Volume of fluid medium taken 50 ml
Temperature 125°C
Duration 3hrs
Fluid medium used for polymer ppt Acetone
Calculations
Weight of dissolved polymer layer after drying 0.23 g
Weight of separated polymer layer 0.33 g
Total mass 0.56g
Volume of mixed fluid medium remains after separation process Approx. 45 ml xylene + 50 mL acetone
From Table 2, a mass balance was obtained on comparing the weight of packaging material taken before separation and the total mass of the layers after separation. From Table 2 it was confirmed that the separating medium can be reused 2 times. The third time layer separation was not achieved completely however prolonged heating can result in complete layer separation. This contributes towards the cost effectiveness in layer separation process in reusing the separating medium.
Further, Table 2 indicated that the addition of surfactant decreases the time of layer separation and separation of one more layer is observed. The time of separation of layers was same when the concentration of surfactant was increased to 10 %. Non-ionic surfactant, isotridecanol ethoxylate is compatible with the RELSOLVE (separating medium) while the anionic surfactant based on lauryl phosphate is not suitable and a solid mass is precipitated.
Furthermore, from Table 1 and Table 2 it was confirmed that when RELSOLVE is used alone only two layers .i.e. the top printed layer and the inner transparent layer were separated while the addition of surfactant with RELSOLVE separated the top printed layer into two layers. Improvement in separation of layers in the packaging material was achieved when non-ionic surfactant was used with the RELSOLVE separating medium.
• pH study
To understand the separation process by using the RELSOLVE with the non-ionic surfactant, a study on the pH was conducted. The study indicated that, at a pH of 10.5 the separation of packaging material into three layers occurred with dissolution of aluminium layer. If the pH is increased or decreased than 10.5 the separation will not be effective.
Characterization of the separated polymer layers of VM 1 and identification of constituents of polymer layers by FTIR and DSC.
The separated layers of VM 1 were characterized by Differential Scanning Calorimetry (DSC) and Fourier Transform Infrared (FTIR) to identify the materials present in each layer.
The FTIR and DSC study were carried out for 4 separated polymer layers from VM-1 obtained in experiment no 1 and 2.
The results are as follows:
i) From Figure 10 (a) it was observed that for the top transparent layer, the FTIR spectrum showed C=O stretching and presence of phenyl ring. Further, the DSC analysis of Figure 11(a) indicated the melting point as 253°C. Hence based on the FTIR and DSC analysis, it was confirmed that the top layer is of polyethylene terephthalate (PET).
ii) From Figure 10 (b) it was observed that, for the middle printed layer, the FTIR spectrum showed CH2 stretching and C-H rocking vibration bands. Further, the DSC analysis of Figure 11 (b) indicated a melting point of 112 °C. Hence, based on the FTIR and DSC analysis, it was confirmed that the middle layer is of low density polyethylene (LDPE).
iii) From Figure 10 (c) it was observed that the disintegrated polymer layer separated as white precipitate showed CH2 stretching and C-H rocking vibrations. Further, the DSC analysis of and Figure 11 (c) indicated a melting point of 125 ºC. Hence, based on the FTIR and DSC analysis, it was confirmed that the disintegrated polymer layer separated as white precipitate is of linear low density polyethylene (LLDPE).
iv) Figure 11 (d) of FTIR and DSC confirmed the inside transparent layer as PET and the observations are similar to that of top transparent layer.
For VM1, 4 nos. of polymer layers and a sandwiched aluminium layer was separated
1) PET –Transparent 2) LDPE- middle printed 3) Aluminium layer 3) LLDPE – tie layer 4) PET – inside transparent layer.
Figure 3 illustrates the packaging structure of the multilayer packaging film of VM1.
Experiment No 3: Process for the separation of polymer layers in multilayer packaging films (VM2) without using surfactants in accordance with the present disclosure.
Step 1: Layer separation in multilayer packaging material using RELSOLVE (sodium salt of 6-amino caproic acid) (separating medium).
Vendor material-2 (VM2) was used as the multilayer packaging film.
0.53 g of vendor material 2 (VM 2) was treated with 50 mL of 5% RELSOLVE solution in DM water at 50 °C under stirring using a magnetic stirrer. Separation of layers was observed after 5 hours with dissolution of aluminium layer. Two layers i.e. the top printed layer and the inside transparent layer got separated. The layers were washed with water and kept for atmospheric drying.
Step 2: Fluid medium treatment.
The fluid medium treatment was carried out for top printed layer for further separation. The top layer was treated with xylene at 125 °C for 3 hours and the transparent layer was separated by filtration at hot condition to obtain separated transparent layers and a filtrate comprising white precipitate. The white precipitate was cooled and separated. The separated transparent layers were washed with water and dried. Similarly, the inner transparent layer was also treated with xylene at 125 °C for 1 hour and separation of 2 constituent layers was carried out.
Table 3 illustrates the mass balance of the layer separation process of VM2, without usage of surfactant.
Table 3: Mass balance calculations of separation process of VM2.
Multilayer packaging film VM2 (Without surfactant) (Step 1)
Conditions
Weight of sample 0.53 g
Concentration of alkali metal salt of an aliphatic amino acid 5% RELSOLVE
Volume of a solution of alkali metal salt of an aliphatic amino taken 50ml
Temperature 50 °C
Duration 5h
Calculations
Volume of fluid medium remains after separation process 42ml
Weight of separated Transparent layer 0.34 g
Weight of top printed layer 0.18 g
Weight of aluminium layer:
Weight of sample taken – total weight of separated polymer layer 0.53-0.52 = 0.1g
Total mass 0.53g
Separation of top printed layer VM2 (organic fluid medium treatment step 2)
Conditions
Weight of sample (separated top printed layer) 0.18 g
Fluid medium Xylene
Volume of fluid medium taken 50ml
Temperature 125°C
Duration 3 h
Calculations
Volume of fluid medium remains after separation process 45 ml
Weight of separated top transparent layer 0.10 g
Weight of printed polymer layer 0.07 g
Separation of transparent layer VM2 (organic fluid medium treatment step 2)
Conditions
Weight of sample (separated transparent layer) 0.34 g
Fluid medium Xylene
Volume of fluid medium taken 50ml
Temperature 125°C
Duration 1 h
Fluid medium Used for Polymer PPT Acetone (50ml)
Calculations
Volume of fluid medium remains after separation process 45 ml
Weight of separated Transparent layer 0.17 g
Weight of dissolved polymer layer after precipitation & drying 0.19 g
Experiment No 4: Process for the separation of polymer layers in multilayer packaging films (VM2) by using surfactants in accordance with the present disclosure.
Step 1: Layer separation in multilayer packaging material using RELSOLVE (sodium salt of 6-amino caproic acid) (separating medium) and a surfactant
Vendor material -2 (VM2) was used as the multilayer packaging film.
1 g of small pieces of the multilayer film of VM2 was treated with 50 mL solution of 5% surfactant and 5 % RELSOLVE in DM water at 50 °C. Separation of 2 polymer layers with the dissolution of aluminium layer was observed in 4 hours.
Step 2: Treatment with fluid medium
This step was carried out similar to step 2 of experiment no 3.
From Table 3 and experiment No 3 it was observed that when RELSOLVE is used alone, the time of separation is almost doubled. The usage of surfactant has significantly reduced the time of separation. Improvement in separation of layers in packaging material is achieved when non-ionic surfactant is used with the RELSOLVE separating medium.
Characterization and identification of the separated polymer layers of VM2 and identification of constituents of polymer layers.
The separated layers of VM2 were characterized by Differential Scanning Calorimetry (DSC) and Fourier Transform Infrared (FTIR) to identify the materials present in each layer. The FTIR and DSC studies were carried out for 4 separated polymer layers from VM-2 obtained in experiment no 3 and 4. It was observed that the top transparent layer was of PP, middle printed layer was of LDPE, tie layer was of aluminium layer and LLDPE layer and the inside transparent layer is of PET.
Figure 4 illustrates the schematic representation of the layer separation process of VM2. Figure 5 illustrates the packaging structure of the multilayer packaging film of VM2.
Effect of temperature:
Effect of temperature was studied using two vendor materials (VM1 and VM2) for the separation process involving the separation medium RELSOLVE at room temperature (25°C) and at 50 °C. The study indicated that the separation of layers takes place in lesser time at higher temperature than at room temperature (25°C). Separation of layers is 12 fold times faster at higher temperature (50°C) as compared to separation at room temperature (25°C).
Effect of concentration of the separating medium RELSOLVE:
Effect of concentration of the separating medium was studied using vendor material (VM2) at temperature (50 °C). The results indicated 7 hours to 8 hours of time for separation at 10 wt% concentration while a lesser time of 5 hours to 6 hours was observed for 5 wt% concentration. Aluminium layer was separated in soluble form in all concentration. A concentration of 100 wt% RELSOLVE separating medium was also studied and 8 hours to 9 hours separation time was observed. Thus, the lower concentration of RELSOLVE lowers the separation time.
Xylene and dimethyl sulfoxide (DMSO) were used as the fluid medium for the treatment of the separated polymer layer from step 1. Xylene was found to be effective for all the multilayer film, while DMSO was effective only for few vendors materials depending on the constituent layers.
In large scale separation process, the polymer layers separated after xylene treatment can be segregated into individual polymer through the difference in their densities.
Experiment No 5: Process for the separation of polymer layers for recycling blister pack of pharmaceutical tablet 1 without using surfactants in accordance with the present disclosure.
Type I blister pack: Aluminium – Polymer (Al-P) type (single polymer layer)
0.51 g of cut pieces of a blister pack of a pharmaceutical tablet 1, were treated with 50 mL of 5 % RELSOLVE solution in DM water at 90 °C under stirring using a magnetic stirrer. Separation of polymer layers was observed after 3 hours with dissolution of aluminium layer. Complete dissolution of aluminium took place in 6 hours. The separated layer was washed with water and kept for atmospheric drying.
Characterization of the separated layers of blister pack of pharmaceutical tablet 1 and identification of constituents of polymer layers.
The separated layers of blister pack of pharmaceutical tablet 1 were characterized by DSC and FTIR. The DSC and FTIR characterization confirmed that the polymer layer is of PVC. The FTIR spectrum of PVC demonstrated peaks around 2900 cm-1, which attributes to CH2 asymmetric and symmetric stretching vibration modes. The peak at 1426 cm-1 is assigned to the C -H aliphatic bending bond. The peak at 1253 cm-1 is attributed to the bending bond of C - H near Cl. The C-C stretching bond of the PVC backbone chain is observed in the range of 1000 cm-1 to 1100 cm-1. The absorbance peaks was in the range of 600 cm-1 to 650 cm-1 corresponding to the C-Cl gauche bond.
Figure 6 illustrates the structure of the aluminium–polymer blister pack 1 with identified polymer layer of the pharmaceutical tablet 1.
Table 4 illustrates the mass balance of layer separation process of blister pack 1.
Table 4: Mass balance and number of reuses carried out by using same separating medium of blister pack of pharmaceutical tablet 1.
Pharmaceutical tablet 1 – Al-P type - layer separation (without surfactant) (Step 1)
Reaction Conditions 1st Separation 2nd Separation
Weight of sample 0.51 g 0.50 g
Concentration of alkali metal salt of an aliphatic amino acid 5% RELSOLVE 5% RELSOLVE
Volume of a solution of alkali metal salt of an aliphatic amino acid taken 50 ml 47.5 ml
(filtrate from 1st separation)
Temperature 90°C 90°C
Duration 3h 3h
Mass balance
Weight of sample taken 0.51 g 0.50 g
Weight of separated polymer layer 0.45 g 0.45 g
Weight of aluminium layer:
Weight of sample taken – total weight of separated polymer layer 0.51 – 0.45 = 0.06 g 0.50-0.45 = 0.05 g
Total mass after layer separation 0.51 g 0.50 g
Volume of fluid medium remains after separation process 47.5 ml 42.5 ml
Weight of precipitated powder 0.041 g 0.39 g
From table 4 two separations by using the same fluid medium were observed to be efficient. Third separation was not complete and dissolution of Al was also not proper under same experimental conditions.
Experiment No 6: Process for the separation of polymer layers for recycling blister pack of pharmaceutical tablet 2 using RELSOLVE without using surfactants in accordance with the present disclosure.
Type I blister pack – Aluminium – Polymer (Al-P) type (multiple polymer layer) was used as a multiple packaging layer.
1 g of cut pieces of blister pack of a pharmaceutical tablet 2 was treated with 50 mL of 5 % RELSOLVE (separating medium) solution in DM water at 90 °C under stirring using a magnetic stirrer. Separation of two polymer layers (middle flexible layer and bottom rigid layer) was observed after 2 hours with dissolution of aluminium layer. Complete dissolution of aluminium took place in 6 hours. The separated layer was washed with water and kept for atmospheric drying.
Characterization of the separated layers of blister pack of pharmaceutical tablet 2 and identification of constituents of polymer layers
The separated layers of blister pack of pharmaceutical tablet 2 were characterized by DSC and FTIR. The DSC, Dynamic mechanical analysis (DMA) and FTIR characterization confirmed that the polymer layers, middle flexible layer and bottom rigid layer were of PVC.
Figure 7 illustrates the packaging structure of the blister pack of the pharmaceutical tablet 2.
Experiment No 7: Process for the separation of polymer layers for recycling blister pack of pharmaceutical tablet 3 without using surfactants in accordance with the present disclosure.
Type II blister pack – Aluminium – Aluminium (Al – Al) type was used as a multiple packaging layer.
1 g of cut pieces of blister pack of a pharmaceutical tablet 3 were treated with 50 mL of 5 % RELSOLVE (separating medium) solution in DM water at 110°C under stirring using a magnetic stirrer. Separation of the polymer layer next to the lidding aluminium layer was observed after 3 hours with dissolution of lidding aluminium layer. Complete dissolution of aluminium took place in 6 hours. The separated layer was removed by filtration and the separation process was continued using the filtrate and the remaining unseparated part of the blister pack. Further reflux was continued at the same temperature for 6 hours and the sandwiched Al layer was dissolved leading to the separation of bottom polymer layer. The separated polymer layers were washed with water and kept for atmospheric drying.
Characterization of the separated layers of blister pack of pharmaceutical tablet 3 and identification of constituents of polymer layers
The separated layers of blister pack of pharmaceutical tablet 3 were characterized by DSC and FTIR. The DSC, Dynamic mechanical analysis (DMA) and FTIR characterization confirmed that the separated layers were of polyamide 6.
Experiment No 8: Process for the separation of polymer layers for recycling blister pack of pharmaceutical tablet 3 by using surfactants in accordance with the present disclosure.
0.51 g of cut pieces of Al–Al blister pack of a pharmaceutical tablet 3 were treated with 50 mL of separating medium containing 5 % of RELSOLVE and 5% of non-ionic surfactant solution in DM water in a flask fitted with a condenser at a temperature of 110°C under stirring by using a magnetic stirrer. Separation of the polymer layer next to the lidding aluminium layer was observed after 2 hours with dissolution of lidding aluminium layer. Complete dissolution of aluminium took place in 3 hours. The separated layer was removed by filtration and the separation process was continued using the filtrate and the remaining unseparated part of the blister pack. Further, reflux was continued at 110°C and separation of bottom polymer layer was observed with dissolution of sandwiched Al layer in 4 hours.
Characterization of the separated layers of blister pack of pharmaceutical tablet 3 by using surfactant and identification of constituents of polymer layers
The separated layers of blister pack of pharmaceutical tablet 3 were characterized by DSC and FTIR. DSC of the polymer layer next to the lidding Al layer showed a melting peak at 216°C corresponding to polyamide 6. The FTIR spectrum showed characteristic peaks such as stretching vibration modes at 1227 and 1093 cm-1 corresponding to CN functional group, bending NH mode around 1540 cm-1, stretching vibration mode of carbonyl group at 1634 cm-1. The mass for this layer separation process is summarized in Table 5.
Table 5: Mass balance of the layer separations using RELSOLVE with and without surfactant of blister pack of pharmaceutical tablet 3
Blister pack layer separation (pharmaceutical tablet 3) - Al – Al Type
Reaction Conditions Without surfactant With surfactant
Weight of sample 0.51 g 0.41 g
Concentration of alkali metal salt of an aliphatic amino acid 5% RELSOLVE 5% RELSOLVE + 5% Surfactant
Volume of a solution of alkali metal salt of an aliphatic amino acid 50 ml 41 ml
Temperature 110°C 110°C
Total duration (for both layers) Approx. 12hrs Approx. 10hrs
Mass balance
Weight of sample taken 0.51 g 0.41 g
Weight of separated polymer layer (1st Layer, Polyamide 6) 0.05 g 0.04 g
Weight of separated polymer layer (2nd Layer, polyamide 6) 0.17 g 0.13 g
Weight of aluminium layer:
Weight of sample taken – total weight of separated polymer layer 0.51 – 0.22 = 0.29 g 0.51 – 0.22 = 0.29 g
Total mass after separation 0.51 g 0.46 g
Volume of fluid medium remains after separation process 42 ml 35 ml
Weight of precipitated powder 0.93 g 0.67 g
From table 5 it was observed that the addition of surfactant reduced the time of complete separation by 2 hours to 3 hours compared to the time taken in the absence of the surfactant under same experimental conditions.
Figure 8 illustrates the packaging structure of the Alu–Alu blister pack of a pharmaceutical tablet 3.
Experiment No 9: Process for the separation of polymer layers for recycling blister pack of pharmaceutical tablet 4 without using surfactants in accordance with the present disclosure.
Type II blister pack – Aluminium – Aluminium (Al – Al) type:
Step 1:
0.51 g of cut pieces of blister pack of a pharmaceutical tablet 4 were treated with 50 mL of 5 % RELSOLVE solution in DM water at a temperature of 90°C under stirring by using a magnetic stirrer. Separation of the polymer layer next to the lidding aluminium layer was observed after 3 hours with dissolution of lidding aluminium layer. Complete dissolution of aluminium took place in 6 hours. The separated polymer layer was washed with water and kept for atmospheric drying.
Characterization of the separated layers of blister pack of pharmaceutical tablet 4 and identification of constituents of polymer layers
The separated layers of blister pack of pharmaceutical tablet 4 in step I were characterized by DSC and FTIR.
Based on DSC analysis, the separated layer was identified as polyamide 6 (Nylon 6). DSC of the polymer layer next to the lidding Al layer showed a melting peak at 219°C corresponding to polyamide 6 (figure 7). DSC melting endotherm of the first polymer layer next to Al lidding layer.
Figure 9 illustrates the packaging structure of the Al-Al blister pack of pharmaceutical tablet 4 in accordance with the present disclosure.
Step 2:
The separation of the remaining layer bonded with the polymer layer was performed by following two methods:
Method 1:
The separation of the remaining aluminium layer bonded with the polymer layer was achieved by treating with xylene at 120°C. The polymer layer bonded to the aluminium layer was softened and disintegrated with separation of the aluminium layer.
Method 2:
The disintegration of the bottom polymer layer was avoided by further treating the remaining aluminium layer bonded with bottom polymer layer with RELSOLVE separating medium.
The remaining aluminium layer bonded with the polymer layer was separated by treating again with 150 mL of 5 % of RELSOLVE at 90° C. Complete separation of the bottom layer was observed with dissolution of aluminium layer in 12 hours. The layers were washed with DM water, dried and characterized to identify the polymer.
Characterization of the separated layers of blister pack of pharmaceutical tablet 4 and identification of constituents of polymer layers.
The separated layers of blister pack of pharmaceutical tablet 4 in step II were characterized by DSC and FTIR. DSC and FTIR characterization confirmed that the bottom polymer layer separated was PVC.
Experiment No 10: Process for the separation of polymer layers for recycling blister pack of pharmaceutical tablet 4 by using surfactants in accordance with the present disclosure.
0.51 g of cut pieces of Al–Al blister pack of a pharmaceutical tablet 4 were treated with 50 mL of 5 % RELSOLVE solution and 5% non-ionic surfactant solution in DM water and was refluxed in a flask fitted with a condenser at a temperature of 150°C under stirring using a magnetic stirrer. Separation of the polymer layer next to the lidding aluminium layer observed after 2 hours with dissolution of lidding aluminium layer. Complete dissolution of aluminium taken place in 3 hours. The layer separated was removed by filtration and the separation process is continued using the filtrate and the remaining unseparated part of the blister pack. Further, reflux was continued at 150°C and separation of bottom polymer layer was observed with dissolution of sandwiched Al layer in 4 hours.
Figure 9 illustrates the packaging structure of the Al-Al blister pack of pharmaceutical tablet 4.
Table 6 illustrates the mass balance for this layer separation process.
Table 6: Mass balance of the layer separations using RELSOLVE with surfactant of blister pack of pharmaceutical tablet 4
Blister pack layer separation (pharmaceutical tablet 4) Al – Al Type
Reactions Conditions
Weight of sample 0.51 g
Fluid medium 5% RELSOLVE & 5% Surfactant
Volume of fluid medium taken 50 ml
Temperature 150°C
Duration (for both the layer separation) Approx. 10 h
Mass balance
Weight of sample 0.51 g
Weight of separated polymer layer (1st Layer, Nylon 6) 0.05 g
Weight of separated polymer layer (2nd Layer, PVC) 0.15 g
Weight of aluminium layer:
Weight of sample taken – total weight of separated polymer layer 0.51 – 0.20 = 0.31 g
Total mass 0.51 g
Weight of precipitated powder 1.1 g
Volume of fluid medium remains after separation process 42 ml
From table 6 it was confirmed that the usage of the surfactant along with RELSOLVE increased the efficiency of separation, nearly 40-50 % reduction in the time of separation was observed.
Layer separation of aluminium – aluminium blister pack is achieved by the separating chemical in two step reaction. The nature of the bottom polymer layer and the adhesives in between the sandwiched aluminium layer and bonded bottom layer play important role in the separation time and separation medium.
TECHNICAL ADVANCEMENTS
The present disclosure described herein above has several technical advantages including, but not limited to, the realization of a process for the separation of polymer layers in multilayer packaging films that;
• is simple, economic and an environment friendly;
• requires minimum number of steps; and
• requires minimum usage of a fluid medium.
Throughout this specification, the word “comprise”, or variations such as “comprises” or “comprising, will be understood to imply the inclusion of a stated element, integer or step,” or group of elements, integers or steps, but not the exclusion of any other element, integer or step, or group of elements, integers or steps.
The use of the expression “at least” or “at least one” suggests the use of one or more elements or ingredients or quantities, as the use may be in the embodiment of the invention to achieve one or more of the desired objects or results. While certain embodiments of the inventions have been described, these embodiments have been presented by way of example only, and are not intended to limit the scope of the inventions. Variations or modifications to the formulation of this invention, within the scope of the invention, may occur to those skilled in the art upon reviewing the disclosure herein. Such variations or modifications are well within the spirit of this invention.
The numerical values given for various physical parameters, dimensions and quantities are only approximate values and it is envisaged that the values higher than the numerical value assigned to the physical parameters, dimensions and quantities fall within the scope of the invention unless there is a statement in the specification to the contrary.
While considerable emphasis has been placed herein on the specific features of the preferred embodiment, it will be appreciated that many additional features can be added and that many changes can be made in the preferred embodiment without departing from the principles of the disclosure. These and other changes in the preferred embodiment of the disclosure will be apparent to those skilled in the art from the disclosure herein, whereby it is to be distinctly understood that the foregoing descriptive matter is to be interpreted merely as illustrative of the disclosure and not as a limitation. ,CLAIMS:WE CLAIM:
1. A process for the separation of polymer layers in multilayer packaging films, said process comprising the following steps:
i) treating multilayer packaging films with a solution of alkali metal salt of an aliphatic amino acid and optionally, at least one surfactant at a first predetermined temperature for a first predetermined time period to obtain at least two separated polymer layers; and
ii) optionally, treating said separated polymer layers with a fluid medium at a second predetermined temperature for a second predetermined time period to obtain further separated polymer layers.
2. The process as claimed in claim 1, wherein said multilayer packaging film is selected from the group consisting of multilayer structure and multimaterial structure.
3. The process as claimed in claim 2, wherein said multimaterial structure comprises at least one metal layer and at least one polymer layer.
4. The process as claimed in claim 3, wherein said metal layer is an aluminium layer.
5. The process as claimed in claim 2, wherein said multilayer structure comprises at least two polymer layers.
6. The process as claimed in claim 5, wherein said at least two polymer layers are same.
7. The process as claimed in claim 5, wherein said at least two polymer layers are different.
8. The process as claimed in claims 3 and 5, wherein said polymer layer is at least one selected from the group consisting of polypropylene (PP), polyethylene (PE), polyvinyl chloride (PVC), polyamide, polyethylene terephthalate (PET) and polyvinylidene chloride (PVDC).
9. The process as claimed in claim 1, wherein said alkali metal salt in said alkali metal salt of said aliphatic amino acid is sodium salt of aliphatic amino acid.
10. The process as claimed in claim 9, wherein said sodium salt of aliphatic amino acid is sodium salt of 6-amino caproic acid.
11. The process as claimed in claim 1, wherein a mass by volume ratio of said multilayer packaging films to said solution of alkali metal salt of an aliphatic amino acid is in the range of 1:40 to 1:120.
12. The process as claimed in claim 1, wherein said solution of said alkali metal salt of said aliphatic amino acid comprises said alkali metal salt of an aliphatic amino acid and water.
13. The process as claimed in claim 1, wherein a concentration of said alkali metal salt of said aliphatic amino acid in said solution is in the range of 2% to 20%.
14. The process as claimed in claim 1, wherein said surfactant is a non-ionic surfactant.
15. The process as claimed in claim 14, wherein said non-ionic surfactant is selected from the group consisting of fatty alcohol ethoxylate, fatty alkanolamides, and amine oxides.
16. The process as claimed in claim 15, wherein said fatty alcohol ethoxylate is selected from the group consisting of isotridecanol ethoxylate, fatty acid alkoxylate, and alkyl phenol ethoxylate.
17. The process as claimed in claim 1, wherein said first predetermined temperature is in the range of 40 °C to 150 °C.
18. The process as claimed in claim 1, wherein said first predetermined time period is in the range of 2 hours to 20 hours.
19. The process as claimed in claim 1, wherein said fluid medium is selected from group consisting of xylene, chlorobenzene and ethyl benzene.
20. The process as claimed in claim 1, wherein said second predetermined temperature is in the range of 100 °C to 200 °C.
21. The process as claimed in claim 1, wherein said second predetermined time period is in the range of 30 minutes to 400 minutes.

Dated this 10th day of June, 2024

_______________________________
MOHAN RAJKUMAR DEWAN, IN/PA – 25
OF R. K. DEWAN & CO.
AUTHORIZED AGENT OF APPLICANT

TO,
THE CONTROLLER OF PATENTS
THE PATENT OFFICE, AT MUMBAI