A method for obtaining reusable containers and a cleaning composition

Abstract

The invention relates to a method of obtaining reusable containers and a cleaning composition. The method involves pre-treating a contaminated container with an alkaline solution, followed by the treating with cleaning composition in stages. The pre-treated and partially cleaned contaminated container treated with a first solvent mixture consisting of non-polar solvents to obtain a clean container without residual contamination. Further, the clean container without residual contamination are treated with a second solvent mixture of polar and non-polar solvents to obtain a print free clean container, followed by water washing to remove traces of solvent. The containers are then wet wiped, dried and inspected to obtain the reusable container. The inspection of the container further comprises screening and selecting the clean containers for reused. The discarded clean containers are recycled for preparing granules. The method is environment-friendly, cost-effective, energy-saving, and reduces time consumption.

Description

[0001] A method for obtaining reusable containers and a cleaning composition

[0002] FIELD

[0003] The present invention relates to the field of waste management. Particularly, the present invention relates to a method for obtaining reusable containers and a cleaning composition.

[0004] BACKGROUND

[0005] The background information herein below relates to the present disclosure but is not necessarily prior art.

[0006] Industries such as food, beverages, paints, chemicals and pharmaceuticals use containers to store the raw materials as well as the finished products. However, once their purpose is served, these containers contribute to the waste and thus burden the environment. As per the report (2019-20) of the Central Pollution Control Board (CPCB), 3.5 million metric tonnes of plastic waste are generated in India annually. Around 50% of the total plastic waste produced is recycled.

[0007] Recycling and reuse of plastic waste can contribute to the eco-conscious and circular economy. Recycling aims at first making high-quality granules from waste material which are then used for manufacturing new products. However, thorough cleaning of the contaminated containers is an essential step prior to recycling or reusing the containers. The contamination or the residues of the stored material in the containers can degrade the quality of the resulting granules in terms of reduced tensile strength and decreased impact resistance, compromised visual appearance and substandard finished goods.

[0008] Cleaning of the contaminated container can be achieved either by manual scrubbing or by chemicals. However, often the cleaning methods come with their own set of challenges such as deterioration of surface quality and / or reduction of the strength of the container material. Sometimes the chemicals used for cleaning may pose hazards to the environment as well as to the humans handling them. Reference may be made to a patent application US20060089281A1, titled “Methods and compositions for paint removal”, which relates to the use of compositions for removing coatings from a substrate. However, the chemicals used in the invention operate at a temperature of 110° C or more and the immersion time is in the range of 20 - 120 minutes. Reference may be made to a patent application W02011041837A1, titled “Graffiti removal method and composition”. However, the composition described in the patent application is not applicable for the removal of the dye and / or the pigment from a surface.

[0009] In view of the challenges related to available solutions, there is an urgent need for a method for obtaining reusable containers by removing the contaminations and the printing ink residues. There is an unsolved need to develop a cleaning composition to remove such contamination. Therefore, the present invention is a combination of traditional and modern technology in order to a provide solution, which is economical and a measure for the waste management.

[0010] OBJECTS

[0011] Some of the objects of the present disclosure, which at least one embodiment herein satisfies, are as follows:

[0012] An object of the present invention is to provide a method for obtaining reusable containers and a cleaning composition.

[0013] Another object of the present invention is to provide a method for obtaining reusable containers by applying alkaline solution, followed by treatment with a cleaning composition.

[0014] Another object of the present invention is to provide a method for obtaining reusable containers using a cleaning composition comprising a first solvent mixture and second solvent mixture.

[0015] Another object of the present invention is to provide a method for obtaining reusable containers by removing contamination from the container surface(s) with the first and second solvent mixtures of polar and non-polar solvents and chemical solutions. Still another object of the present invention is to provide a method for obtaining reusable containers without deteriorating the surface quality and material strength of the containers for reuse.

[0016] Yet another object of the present invention is to provide a method for obtaining reusable containers of materials such as plastic, metal and glass, contaminated with paints, oil, lubricants, grease, ink, printing ink, and food and beverage residues.

[0017] Yet another object of the present invention is to provide granules from the clean containers characterized by Material Flow Index (MFI), ash (%), Izod and density.

[0018] 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.

[0019] SUMMARY

[0020] The application relates to a method for obtaining reusable containers and a cleaning composition. The method comprises the steps of pre-treating a contaminated container with an alkaline solution comprising at least one base in water in an amount in a range of 0.5 % w / v to 30 % w / v at a predetermined temperature for a predetermined time period to obtain a partially cleaned contaminated container. The partially cleaned contaminated container is treated with a cleaning composition. In a first stage, the cleaning composition is treated with a first solvent mixture consisting of predetermined amounts of non-polar solvents selected from A, B, C and D to obtain a clean container without residual contamination. In a second stage, the container without residual contamination is treated with a second solvent mixture consisting of predetermined amounts of a mixture of polar and non-polar solvents selected from E, F and G to obtain a print free clean container. Further, the print free clean container is water washed to obtain washed container, and is wet wiped, followed by drying and inspecting to obtain the reusable container.

[0021] A cleaning composition comprises a first solvent mixture and a second solvent mixture.

[0022] The first solvent mixture comprises solvent A in the range of 45 % v / v to 100 % v / v; solvent B in the range of 0 % v / v to 25 % v / v; solvent C in the range of 0 % v / v to 20 % v / v; and solvent D in the range of 0 % v / v to 10 % v / v. The second solvent mixture comprises solvent E in the range of 50 % v / v to 100 % v / v; solvent F in the range of 0 % v / v to 30 % v / v, and solvent G in the range of 0 % v / v to 10 % v / v.

[0023] The solvent A is selected from turpentine, camphene, bornyl acetate, limonene and thymol; the solvent B is selected from toluene, ethylbenzene, chlorobenzene, styrene, cumene; the solvent C is selected from xylene, phenol, aniline, cresols and biphenyl; and the solvent D selected from hexane, cyclohexane, pentane and heptane. The solvent E is selected from ethyl acetate, butyl acetate, isopropyl acetate, ethyl formate and amyl acetate; the solvent F is selected from isopropyl alcohol, ethanol, methanol, diethyl ether and dimethyl sulfoxide, and the solvent G is selected from acetone, methyl ethyl ketone, diethyl ketone, acetophenone and methyl isobutyl ketone.

[0024] The plastic granules obtained from the clean containers are characterized by Material Flow Index (MFI) in the range of 9-9.5 gm / 10 minutes; ash (%) in the range of 1.2 % to 3.0 %; Izod in the range of 110-150 J / m; and density in the range of 0.90 to 1.04 gm / cc.

[0025] BRIEF DESCRIPTION OF THE ACCOMPANYING DRAWING

[0026] The method for obtaining reusable containers and a cleaning composition of the present disclosure will now be described with the help of the accompanying drawing, in which:

[0027] Figure 1 illustrates the flow diagram for the method of obtaining reusable containers; and

[0028] Figure 2 illustrates the photographic images of container before and after method of obtaining reusable containers;

[0029] Legend and legend description

[0030] Legend Description

[0031] 100 Method for obtaining reusable containers;

[0032] 101 Preliminary examination of contaminated containers;

[0033] 102 Pre-treatment of container surface(s);

[0034] 103 Treatment of container surface(s) with a cleaning composition

[0035] 104 water washing the print free clean container, followed by wet wiping; and

[0036] 105 Drying and inspection to obtain the reusable container.

[0037] DETAILED DESCRIPTION Embodiments, of the present disclosure, will now be described with reference to the accompanying drawing.

[0038] 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.

[0039] 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.

[0040] When an element is referred to as being "mounted on," “engaged to,” "connected to," or "coupled to" another element, it may be directly on, engaged, connected or coupled to the other element. As used herein, the term "and / or" includes any and all combinations of one or more of the associated listed elements.

[0041] 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. Terms such as “inner,” “outer,” "beneath," "below," "lower," "above," "upper," and the like, may be used in the present disclosure to describe relationships between different elements as depicted from the figures.

[0042] Industries such as food, beverages, paints, chemicals and pharmaceuticals use containers to store the raw materials as well as the finished products. However, once their purpose is served, these containers contribute to the waste and thus burden the environment.

[0043] Recycling and reuse of plastic waste can contribute to the eco-conscious and circular economy. Recycling aims at first making high-quality granules from waste material which are then used for manufacturing new products. However, thorough cleaning of the contaminated containers is an essential step prior to recycling or reusing the containers. The contamination or the residues of the stored material in the containers can degrade the quality of the resulting granules in terms of reduced tensile strength and decreased impact resistance, compromised visual appearance and substandard finished goods.

[0044] Cleaning of the contaminated container can be achieved either by manual scrubbing or by chemicals. However, often the cleaning methods come with their own set of challenges such as deterioration of surface quality and / or reduction of the strength of the container material. Sometimes the chemicals used for cleaning may pose hazards to the environment as well as to the humans handling them. In view of the challenges related to available solutions, there is an urgent need for a method for obtaining reusable containers and a cleaning composition for removing the contaminations and the printing ink residues. There is an unsolved need to develop a cleaning composition and yet to / retain the quality for reuse. The present invention is a combination of traditional and modem technology in order to provide solution, thereby reducing the environment burden.

[0045] In an aspect of the present disclosure, a method for obtaining reusable containers is provided.

[0046] In an embodiment, the method comprises the steps of:

[0047] (a) pre-treating a contaminated container with an alkaline solution comprising at least one base in water in an amount in a range of 0.5 % w / v to 30 % w / v at a predetermined temperature for a predetermined time period to obtain a partially cleaned contaminated container;

[0048] (b) treating the partially cleaned contaminated container with a cleaning composition in the first stage using a first solvent mixture consisting of predetermined amounts of nonpolar solvents selected from A, B, C and D to obtain a clean container without residual contamination;

[0049] (c) treating the container with cleaned surfaces with the cleaning composition in the second stage using a second solvent mixture consisting of predetermined amounts of a mixture of polar and non-polar solvents selected from E, F and G to obtain a print free clean container;

[0050] (d) water washing the print free clean container to obtain washed container; and

[0051] (e) wet wiping the washed container, followed by drying and inspecting to obtain the reusable contained s).

[0052] In an embodiment, the contaminated container(s) consisting of container(s) contaminated with a printing ink, a paint residue, a paint oil film, a lubricant, grease, an acidic or alkaline layer of chemicals.

[0053] In an embodiment, the oil film has a thickness in the range from 1 to 500 microns, the paint residue is having a thickness in the range from 95 to 3000 microns, the acidic or alkaline layer of chemicals contaminated container is having a thickness in the range of 1 to 70 microns, and the printing ink is having a thickness in the range from 0.5 to 25 microns.

[0054] The method for obtaining reusable containers is described herein below in detail:

[0055] In a first step, the contaminated container(s) is pre-treating with an alkaline solution comprising at least one base in water in an amount in a range of 0.5 % w / v to 30 % w / v at a predetermined temperature for a predetermined time period to obtain a partially cleaned contaminated container(s); In an embodiment, the base is selected from NaOH, KOH, Na2CO3, K2CO3, NaHCO3, and KHCO3. In an exemplary embodiment, the base is NaOH.

[0056] In an embodiment, the alkaline solution is obtained by dissolving a base selected from sodium hydroxide, potassium hydroxide, sodium carbonate, potassium carbonate, sodium bicarbonate and potassium bicarbonate or a combination thereof in water.

[0057] In an exemplary embodiment, the alkaline solution is 2% NaOH in water.

[0058] In an embodiment, the predetermined temperature is in the range of 20 to 70° C. In an exemplary embodiment, the predetermined temperature is 520C.

[0059] In an embodiment, the predetermined time period is in the range of 5 to 45 minutes. In an exemplary embodiment, the predetermined time period is 10 minutes.

[0060] In an embodiment, the pre-treatment loosens the bond of contamination for treatment with first solvent and second solvent.

[0061] In a second step, the partially cleaned contaminated container is treated with a cleaning composition in the first stage using a first solvent mixture consisting of predetermined amounts of non-polar solvents selected from A, B, C and D to obtain a clean container without residual contamination.

[0062] In an embodiment, the first solvent mixture comprises solvent A in the range of 45 % v / v to 100 % v / v; solvent B in the range of 0 % v / v to 25 % v / v; solvent C in the range of 0 % v / v to 20 % v / v; and solvent D in the range of 0 % v / v to 10 % v / v.

[0063] In an embodiment, the first solvent is solvent A selected from turpentine in an amount of 100%.

[0064] In an embodiment, the solvent A is selected from turpentine, camphene, bornyl acetate, limonene and thymol; the solvent B is selected from toluene, ethylbenzene, chlorobenzene, styrene, cumene; the solvent C is selected from xylene, phenol, aniline, cresols and biphenyl; the solvent D selected from hexane, cyclohexane, pentane and heptane. In an exemplary embodiment, the first solvent mixture comprises the solvent A is selected from turpentine in an amount of 45%; the solvent B is selected from toluene in an amount of 25 % v / v; the solvent C is selected from xylene in an amount of 20% v / v; and solvent D is selected from hexane in an amount of 10% v / v.

[0065] In a third step, the clean container without residual contamination is treated with the cleaning composition in the second stage using a second solvent mixture consisting of predetermined amounts of a mixture of polar and non-polar solvents selected from E, F and G to obtain a print free clean container.

[0066] In an embodiment, the second solvent mixture comprises solvent E in the range of 50 % v / v to 100 % v / v; solvent F in the range of 0 % v / v to 30 % v / v, and solvent G in the range of 0 % v / v to 10 % v / v.

[0067] In an embodiment, the solvent E is selected from ethyl acetate, butyl acetate, isopropyl acetate, ethyl formate and amyl acetate; the solvent F is selected from isopropyl alcohol, ethanol, methanol, diethyl ether and dimethylsulfoxide, and the solvent G is selected from acetone, methyl ethyl ketone, diethyl ketone, acetophenone and methyl isobutyl ketone.

[0068] In an exemplary embodiment, the second solvent mixture comprises the solvent E selected from ethyl acetate in an amount of 65%; the solvent F is selected from Isopropyl alcohol in an amount of 25 % v / v; the solvent G is selected from acetone in an amount of 10% v / v.

[0069] In an exemplary embodiment, the second solvent mixture is solvent E selected from ethyl acetate in an amount of 100%.

[0070] In an embodiment, the treatment with the second solvent mixture is manual and machine assisted cleaning.

[0071] In a fourth step, the clean container is water washed to obtain washed container(s).

[0072] In a fifth step, the washed container is wiped, followed by drying and inspecting to obtain the reusable container(s). In the second aspect of the present disclosure, a cleaning composition for obtaining reusable containers is provided.

[0073] In an embodiment, the cleaning composition for obtaining reusable containers comprises a first solvent mixture and second solvent mixture.

[0074] In an embodiment, the first solvent mixture comprises solvent A in the range of 45 % v / v to 100 % v / v; solvent B in the range of 0 % v / v to 25 % v / v; solvent C in the range of 0 % v / v to 20 % v / v; and solvent D in the range of 0 % v / v to 10 % v / v.

[0075] In an embodiment, the second solvent mixture comprises solvent E in the range of 50 % v / v to 100 % v / v; solvent F in the range of 0 % v / v to 30 % v / v, and solvent G in the range of 0 % v / v to 10 % v / v.

[0076] In an embodiment, the solvent A is selected from turpentine, camphene, bornyl acetate, limonene and thymol; the solvent B is selected from toluene, ethylbenzene, chlorobenzene, styrene, cumene; the solvent C is selected from xylene, phenol, aniline, cresols and biphenyl; the solvent D selected from hexane, cyclohexane, pentane and heptanes, the solvent E is selected from ethyl acetate, butyl acetate, isopropyl acetate, ethyl formate and amyl acetate;

[0077] In an embodiment, the solvent F is selected from isopropyl alcohol, ethanol, methanol, diethyl ether and dimethylsulfoxide, and the solvent G is selected from acetone, methyl ethyl ketone, diethyl ketone, acetophenone and methyl isobutyl ketone.

[0078] The contaminated containers are examined for determining their suitability for the reuse or the recycling. Structurally intact containers without any deformity can be advanced for the chemical treatment, while the damaged ones are subjected to appropriate recycling procedures. The containers that are found to be suitable for the reuse are further classified according to their material, volume and the type of contamination. Container accessories including the labels if any are removed before subjecting them to the chemical treatment.

[0079] In an embodiment, the inspection of the container further comprises screening and selecting the clean containers for reused; and recycling the discarded clean containers for preparing granules selected from plastic granules. In an embodiment, the plastic granules are characterized by Material Flow Index (MFI) in the range of 9-9.5 gm / 10 minutes; ash (%) in the range of 1.2 % to 3.0 %; Izod in the range of 110-150 J / m; and density in the range of 0.90 to 1.04 gm / cc.

[0080] In an embodiment, the inspection of the containers after the wet wiping for checking their suitability for reuse involves various checks including, testing for defects in the container material such as bumps, depressions, chipping and cracks; opacity evaluation; transparency evaluation; lead content testing; checking suitability of the container to withstand shipping; dimensional inspection; testing for the parameters such as appearance, volume, thickness and weight of the containers; top load test; elevated internal pressure test; leakage test; collapsibility test and adhesion test.

[0081] In an embodiment, the machine assisted cleaning is done with a plurality of brushes that scrub the container surface(s) with simultaneous application of the second solvent.

[0082] In an embodiment, the machine assisted cleaning is done with the aid of a plurality of brushes attached to a machine to remove residual contamination from the surface of the container without damaging the surface. In an embodiment, the plurality of the brushes is made from polymers, metal, cotton, or any combination thereof.

[0083] The present disclosure is further described in light of the following experiments which are set forth for illustration purpose 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.

[0084] EXPERIMENT

[0085] Example 1 : A method for obtaining reusable containers in accordance with the present disclosure

[0086] A contaminated container was pre-treated with 2% alkaline solution of NaOH at 52° C for 10 minutes to obtain a partially cleaned contaminated container. It was further treated with a mixture of 45 ml of turpentine, 25 ml of toluene, 20 ml Xylene and 10 ml hexane to remove the residual contamination, followed by treating the container(s) with 65 ml of ethyl acetate, 25ml of isopropyl alcohol and 10 ml of acetone to remove the print on the container. The containers were water washed to remove traces of solvent, wiped, dried and inspected to obtain the reusable container. The discarded clean containers during the inspection were recycled to obtain granules.

[0087] Example 2: A method for obtaining reusable containers in accordance with the present disclosure

[0088] A contaminated container was pre-treated with 2% alkaline solution of KOH at 55 degrees Celsius for 25 minutes to obtain a partially cleaned contaminated container(s). It was further treated with a mixture of 45 ml of turpentine, 25 ml of toluene, 20 ml Xylene and 10 ml hexane to remove the residual contamination, followed by treatment with 70 ml of ethyl acetate, 20 ml of isopropyl alcohol and 10 ml of acetone to remove the print on the container(s) to obtain clean container(s). The clean containers were water washed, wiped, dried and inspected to obtain the reusable container(s).

[0089] Example 3: A method for obtaining reusable containers in accordance with the present disclosure

[0090] A contaminated container was pre-treated with 2% alkaline solution of NaOH at 52° C for 10 minutes to obtain a partially cleaned contaminated container. It was further treated with the cleaning composition having 55 ml of turpentine, 20 ml of toluene, 15 ml Xylene and 10 ml hexane in the first stage to remove the residual contamination, followed by treating the container(s) with 65 ml of ethyl acetate, 25ml of isopropyl alcohol and 10 ml of acetone in second stage to remove the print on the container. The containers were water washed to remove traces of solvent, wiped, dried and inspected to obtain the reusable container. The discarded clean containers during the inspection were recycled to obtain granules.

[0091] Example 4: Pre-treatment with the alkaline solution concentration in accordance with the present disclosure

[0092] Example 5: Solvent A composition in accordance with the present disclosure

[0093] Example 6: Solvent B composition in accordance with the present disclosure

[0094] Example 7: Comparative study on the properties of the plastic granules in accordance with the present disclosure The results in the table above clearly indicate the improved Material Flowindex, Izod and density of the granules obtained from the clean containers in accordance with the present disclosure.

[0095] Example 8: Comparative study of manual cleaning versus machine assisted cleaning with respect of time taken and solvent first and second for batch of 30 contaminated containers / pail, each of capacity 20 L. Data represents the average values for a batch of 30 cleaned manually and another batch of 30 pails cleaned by machine

[0096] The table above indicates that the time for cleaning and required volume of the first and the second solvent for removing the contamination and printing ink from the inner and the outer surface is lesser when done with the machine assistance as compared to manual cleaning. The manual and mechanical cleaning processes reveals that the mechanical approach offers a more systematic and consistent method, leading to potentially improved cleaning outcomes in terms of contaminant and print removal.

[0097] Example 9: Comparative study of physical properties of contaminated containers before and after the chemical treatment Table A

[0098] Table B Example 10: Comparative study of manual and mechanical cleaning efficacy: Solvent 2 Cleaning vs. SynergicCombination of Alkali and Solvent 2 The results indicate the utilization of only "Solvent second” requires a larger quantity of solvent and an extended duration to effectively clean the print from the surface. However, employing an initial treatment with an alkaline solution followed by the application of "Solvent second” results in a notably reduced amount of solvent usage and shorter cleaning time for print removal. This improvement can be attributed to the synergistic combination of alkali and "Solvent second," where the alkali loosens the print's bond, enabling "Solvent second” to effortlessly eliminate the print from the surface. The treatment with the first alkali solution prior to the solvent results in asignificant reduction in the printing ink removal time and lesser quantity of the third solvent as compared to chemical treatment only with the third solvent.

[0099] Example 11 : Comparative experiment and details

[0100]

[0101] Experiment 12: Analysis of the cleaned reusable containers in accordance with present disclosure a. Microbiological Analysis

[0102] The results of the microbiological analysis indicate that the swab taken from the plastic bucket does not display any fungal growth. b. Heavy Metal Analysis There are no prominent traces of heavy metals detected.

[0103] 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.

[0104] TECHNICAL ADVANCEMENTS

[0105] The present disclosure described herein above has several technical advantages including, but not limited to, the realization of method and cleaning composition, which is:

[0106] • environment-friendly, cost-effective, energy-saving, and reduces time consumption;

[0107] • cleaning compositions is not hazardous to the operating personnel;

[0108] • provides a solution to waste disposal, particularly plastics;

[0109] • promotes circular economy; and

[0110] • the granules resulting from the clean and recycled containers undergoing treatment in accordance with the present disclosure are free from any contamination, demonstrate better mechanical properties, and may be used for producing recycled

Claims

WE CLAIM:

1. A method for obtaining reusable containers comprising steps of: a. pre-treating a contaminated container with an alkaline solution comprising at least one base in water in an amount in a range of 0.5 % w / v to 30 % w / v at a predetermined temperature for a predetermined time period to obtain a partially cleaned contaminated container; b. treating the partially cleaned contaminated container with a cleaning composition in the first stage using a first solvent mixture consisting of predetermined amounts of non-polar solvents selected from A, B, C and D to obtain a clean container without residual contamination; c. treating the clean container without residual contamination with the cleaning composition in the second stage using a second solvent mixture consisting of predetermined amounts of a mixture of polar and non-polar solvents selected from E, F and G to obtain a print free clean container; d. water washing the print free clean container to obtain washed container; and e. wet wiping the washed container, followed by drying and inspection to obtain the reusable container.

2. The method as claimed in claim 1 wherein the predetermined temperature is in the range of 20 °C to 70 °C; and the predetermined time period is in the range of 5 minutes to 45 minutes.

3. The method as claimed in claim 1 wherein the alkaline solution is obtained by dissolving base selected from sodium hydroxide, potassium hydroxide, sodium carbonate, potassium carbonate, sodium bicarbonate and potassium bicarbonate or a combination thereof in water.

4. The method as claimed in claim 1 wherein step (a) of pre-treating loosens the bond of contamination for further treatment with first solvent and second solvent; and step (d) of water washing to remove traces of solvents.

5. A cleaning composition for obtaining reusable containers comprising a first solvent mixture and second solvent mixture, wherein the first solvent mixture comprises solvent A in the range of 45 % v / v to 100 % v / v; solvent B in the range of 0 % v / v to 25 % v / v; solvent C in the range of 0 % v / v to 20 % v / v; and solvent D in the range of 0 % v / v to 10 % v / v, and wherein the second solvent mixture comprises solvent E in the range of 50 % v / v to 100 % v / v; solvent F in the range of 0 % v / v to 30 % v / v, and solvent G in the range of 0 % v / v to 10 % v / v.

6. The cleaning composition as claimed in claim 5 wherein the solvent A is selected from turpentine, camphene, bornyl acetate, limonene and thymol; the solvent B is selected from toluene, ethylbenzene, chlorobenzene, styrene, cumene; the solvent C is selected from xylene, phenol, aniline, cresols and biphenyl; the solvent D selected from hexane, cyclohexane, pentane and heptanes, the solvent E is selected from ethyl acetate, butyl acetate, isopropyl acetate, ethyl formate and amyl acetate; the solvent F is selected from isopropyl alcohol, ethanol, methanol, diethyl ether and dimethylsulfoxide, and the solvent G is selected from acetone, methyl ethyl ketone, diethyl ketone, acetophenone and methyl isobutyl ketone.

7. The method as claimed in claim 1, wherein the contaminated container (s) consisting of container(s) contaminated with a printing ink, a paint residue, a paint oil film, a lubricant, a grease, an acidic or alkaline layer of chemicals.

8. The method as claimed in claim 7, wherein the oil film has a thickness in the range from 1 to 500 microns, the paint residue is having a thickness in the range from 95 to 3000 microns, the acidic or alkaline layer of chemicals contaminated container is having a thickness in the range of 1 to 70 microns, and the printing ink is having a thickness in the range from 0.5 to 25 microns.

9. The method as claimed in claim 1, wherein the inspection of the container further comprises:a) screening and selecting the clean containers for reuse; and b) recycling the discarded clean containers for preparing plastic granules.

10. The method as claimed in claim 9, wherein the plastic granules are characterized by Material Flow Index (MFI) in the range of 9-9.5 gm / 10 minutes; ash (%) in the range of 1.2 % to 3.0 %; Izod in the range of 110-150 J / m; and density in the range of 0.90 to 1.04 gm / cc.Richa Arya, IN / PA-4149

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