GB2528495A

GB2528495A - Recycling process

Info

Publication number: GB2528495A
Application number: GB1413118.9A
Authority: GB
Inventors: Adam Walker
Original assignee: WORN AGAIN FOOTWEAR AND ACCESSORIES Ltd
Current assignee: WORN AGAIN FOOTWEAR AND ACCESSORIES Ltd
Priority date: 2014-07-24
Filing date: 2014-07-24
Publication date: 2016-01-27
Anticipated expiration: 2034-07-24
Also published as: GB2528495B; GB201413118D0

Abstract

The invention relates to a process for extracting polyester from packaging. In particular, the invention relates to packaging comprising one or more dyes such as black packaging. The claimed process uses a two stage extraction process to convert waste polyester in clean, reusable polyester. The process comprises (a) contacting the fabric with a first solvent system to form a mixture, (b) maintaining the mixture at a first temperature for a first period of time until substantially all of the dye has been dissolved, (c) removing the first solvent system containing the dissolved dye, (d) contacting the remaining mixture with a second solvent system in order to dissolve the polyester, (e) maintaining the remaining mixture at the second temperature for a second period of time until substantially all of the polyester has been dissolved, (f) removing the second solvent system containing the dissolved polyester, and (g) recovering the polyester from the second solvent system. The second temperature is greater than the first temperature when the two solvent systems are the same. The solvents are food grade solvents such as ethyl benzoate.

Description

Recycling Process

Field of Invention

The invention relates to a process for extracting polyester from packaging. In particular. food and drink packaging comprising one or more dyes and polyesters.

Background to the Invention

Plastics are versatile materials that have revolutionised many sectors of industry over the last 50 years. However, the high demand for plastics coupled with the poor biodegradability has led to arge amounts of plastic waste which is not easy to dispose of. often ending up in landfill. Although recycling processes have been adopted to convert these waste materials into new production materials, there are still many problems associated with plastics recycling.

In particular, plastics have been used extensively in the packaging sector. Key uses include plastic bags. and food packaging. The vast majority of food and drink today is packaged within plastic bottles and containers, usually containing polyester, and as these materials typically have poor biodegradability, it is desirable for these plastics to he recycled. However, the packaging materials, in addition to plastics like polyester, often also include other additives with can complicate the recycling process. The presence of dyes, used to add colour to packaging, is a particular problem.

Waste packaging often includes a mixture of different plastics containing different dyes. Therefore, in order to recycle these materials, plastics must first he separated based on their colour. However, this sorting process is labour intensive and/or requires the use of optical sorting machines which are expensive. Further, the different coloured plastics are processed separately, requiring multiple recycling processes to be performed in parallel, each process producing recycled plastic of a single colour. Although plastics of different colours can be recycled together. it is usually the case that a stronger dye is added to the plastic in order to mask the combination of different dyes present in the resulting recycled. This increases the reliance on dyes and limits the uses of the recycled plastics plastic and reduces the number of times the plastic can be recycled. Further still, there is a significant demand in the industry for colourless plastic (i.e. plastics not containing dyes) as this can be coloured to fit a wide range of applications.

Therefore, what is required is a process for recycling polyester containing packaging comprising on or more dyes to produce clear, reusable plastics.

The invention is intended to address or at least ameliorate these problems.

Summary of the Iliveiltion

There is provided in a first aspect of the invention, a process for extracting polyester from packaging containing one or more dyes comprising the steps of: a) contacting the packaging with a first solvent system to form a mixture; b) maintaining the mixture at a first temperature for a first period of time until substantially all of the dye has been dissolved: c) removing the first solvent system containing the dissolved dye; d) contacting the remaining mixture with a second solvent system in order to dissolve the polyester; e) maintaining the remaining mixture at the second temperature for a second pcriod of time until substantially all of the polyester has been dissolved: I) removing the second solvent system containing the dissolved polyester; and g) recovering the polyester from the second solvent system; wherein the first and second solvent systems each essentially consist of one or more food grade solvents; and wherein the second temperature is greater than the first temperature when the first solvent system and the second solvent system are the same.

The term "food grade solvents" is intended to refer to compounds which are substantially non-toxic and non-harmful. It is an important requirement where recycled p'astics are used to make new packaging materials for the food and drinks industry that no harmful or toxic substances are retained in plastics as a consequence of the recycling process which could leach out into the food or drink contained therein. There is often, albeit at very small concentrations, some residual solvent which remains associated with the recycled polyester. Many countries will not permit the use of recycled polyester or other plastics where the recycling process has involved potentially harmful substances. It is typically the case that "food grade solvents" arc those materials considered to be pennissible for use in the nianufacture of plastics according to legislation such as EU Directive 2002/72/EC.

The inventors have found that the above process allows dyes to be removed from polyester containing packaging without making use of toxic or harmful solvent systems or materials. The first solvent system can he removed using conventional filtration processes leaving the undissolved, dye-free polyester. It is desirable that the polyester does not dissolve in the first solvent system at the first temperature.

The term "dye" or "dyes" is intended to refer to compounds incorporated into materials, polyester containing packaging materials in the present situation, to imbue said materials with a particular colour. In the packaging industry, these dyes are typically organic dyes hut some inorganic dyes and salts of organic dyes are also used.

However, some colouring agents arc very insoluble, typically purely inorganic matcrials such as titania or carbon black. These substantially insoluble materials can often be removed using simple filtration techniques as they form precipitates.

Therefore, reference in the specification to "dyes" is intended to refer to chemical colouring agents. typically organic dyes, which are soluble in organic solvents.

Therefore, this term excludes substantially insoluble coloured matter such as titania or carbon black.

Further, the "dyes" referred to herein are considered to be separate from other additives which do not substantially modify the optical properties of the plastics with which they are combined.

It is typically the case that the second solvent system dissolves substantiafly all of the polyester present in the mixture of steps d) and e). The term "substantially all" is intended to mean greater than 90% of the polyester present in the mixture (for instance 90% to 100%). Typically, the second solvent system dissolves at least 95% of the polyester, more typically at least 99% of the polyester.

The term "solvent system" is intended to mean a homogeneous or heterogeneous combination of one or more solvents. These solvents may or may not he miscible with one another. Typically, the solvent systems will he homogeneous as there is no need to adapt the apparatus performing the process to allow removal of separated solvent layers.

The polyester that is extracted from packaging is typically selected from: polyglycolic acid (PGA). polylactic acid (PLA), polycaprolactone (PCL), polyethylene adipate (PEA). polyhydroxyalkanoate (PHA), polyethylene terephthalate (PET), polybutylene terephthalate (PBT). p01 ytrimeth ylene terephthaIate (PTT), polyethylene naphthalate (PEN) or combination thereof. More typically. thc polyester is polyethylene terephthalate (PET). These polyesters are frequently used in the packaging industry and are often difficult to separate from the dyes they are modified with. As such, this makes them commercially very useful to recycle using the present process.

Although the reaction is typically performed under atmospheric pressure. the process can be performed under higher pressures in order to superheat one or both of the first or second solvent systems. However, this is typically avoided as this usually requires specialised reaction vessels and higher energy conditions which increases the overall cost of the recycling process.

It is often the case that the packaging which is recycled using the claimed process comprises food packaging. The term "food packaging" is intended to cover all trays, bottles, containers, cups. pots, and other vessels for storing solid and liquid foods as well as protective fihs and covers used to seal such containers. Typically. the packaging comprises black packaging. The term "black packaging" is intended to cover those p'astics containing polyesters and a mixture of different dyes wherein at least one of the dyes present masks the appearance of the other dyes. A typical example of this is plastic containers containing carbon black which masks the presence of any other dyes present leaving the container with a black finish.

Black plastics are a particular problem for the packaging industry as it is often not possible to automate the sorting of black plastics from other coloured plastics (for instance using conventional optical sorting measures) and these black plastics often include more additives and dyes than other dyed plastics.

It is also often the case that the packaging comprises bottles. Plastic bottles often contain polyester and many include several common dyes.

The solvent systems used in the invention may he heterogeneous systems comprising two or more immiscible solvents. In this situation, one of the solvents may be selected to dissolve polyester and/or dyes whilst another solvent or solvents may be selected to dissolve common substances found in the packaging being recycled. In use, the heterogeneous systems are typically agitated in order to create a uniform mixture and the packaging is exposed to the mixture. After a period of time, the agitation is halted and the solvent system is allowed to separate and one or more of the immiscible solvent phases can he extracted.

Alternatively, the solvent systems used in the invention may be homogeneous systems and the solvent systems may comprise one or more compounds as described above or combinations thereof in an amount in the range 30% to 100% by mass of the total mass of the solvent system. This upper limit of 100%, is intended to mean practically 100% or 99% or 98%' as. in real world situations, it is never possible to obtain absolute purity. Typically. the solvent system may comprise one or more compounds described above or combinations thereof in an amount of at least 50% by mass of the total mass of the solvent system. Even more typically. the solvent system may comprise one or more compounds described above or combinations thereof in an amount of at least 55%, 60%, 65%, 70%, 75%, 80%, 85%, 90% or 95% by mass of the total mass of the solvent system so, in the range 50% -100%, 55%-l00%, 60%- 100%, 65%-lOO%, 70%-100%. 75%-lOO%. 80%-100%, 85%-l00%. 90%-100% or 95%-l00% by mass of the total mass of the solvent system.

In a first embodiment of the invention, the first solvent system and the second solvent system are different. This allows each solvent system to he tailored to either one or more of the dyes or to the polyester. Accordingly, by using two solvent systems, each adapted for dissolving a specific component of the packaging, the temperature required to extract each component of the plastic is mini mised.

The first solvent system is selected to dissolve the dyes but not the polyester at the first temperature. Further, the first solvent system is typically selected so that dissolution of (lie dye can occur at a reasonable rate at low temperature. Complete dissolution of the dye would eventually occur if the reaction mixture was maintained at room temperature. However, this typically takes a long time (potentially days) which is often not suitable for commercial recycling. Therefore, it is often the case that the first solvent system is heated to speed up this process. A balance is required between raising the temperature to a level sufficient to dissolve the dye at an acceptable rate without increasing the temperature so much that the polyester becomes soluble in the first solvent system or that the first solvent system is evaporated.

Typically, the first temperature is in the range 70°C -120°C, more typically 80°C - 110°C or even more typically 90°C -100°C.

Where the first solvent system and second solvent system are different, it is usually the case that the first solvent system comprises one or more solvents selected from: cycloalkenes: ketones: esters; carbonates: or combinations thereof.

The eycloalkenes used in the first solvent system may comprise limonene and the typical ketones used may comprise cyclopentanone: acetone; or combinations thereof.

It is typically the case that the esters used in the first solvent system are alkyl esters, typically selected from: ethyl acetate; propyl acetate; butyl acetate; isobutyl acetate; tert-butyl acetate; amyl acetate; isoamyl acetate; ethyl propionate; ethyl butyrate; ethyl isohutyrate; propyl propionate: propyl butyrate: hutyl hutyrate: isohuty hutyrate; butyl isobutyrate; isobutyl isobutyrate; ethyl valerate; propyl valerate; butyl valerate; amyl valerate; or combinations thereof.

Where carbonates are used in the first solvent system. the earbonthes are typically selected from dimethyl carbonate. diethyl carbonate or combinations thereof It is often the case that the first solvent system will comprise limonene awl/or ethyl acetate. These solvents are relatively inexpensive, have boiling points which makes them useful to extract polyester and he recycled hut are also already present in many food stuffs and therefore do not impact negatively if residue is retained in the recycled polyester (albeit in small quantities).

The second solvent system may be heated. This encourages polyester to dissolve in the second solvent system. Usually, die secoiid solvent system is heated to a temperature in the range 50°C to 150°C, or more typically in the range 60°C to 130°C.

or even more typically in the range 70°C to 110°C. These temperatures maxi misc the amount and rate of dissolution of polyester whilst minimising the energy required to raise and sustain the temperature of the solvent system. Once a sufficient quantity of polyester has been dissolved, the solvent system may be separated and can be cooled to precipitate the polyester.

There is no particular restriction on the choice of second solvent system provided that said solvent system is a suitable food grade solvent and dissolves polyester.

Preferably, the second solvent system is selected to minimise operating temperatures at which polyester is dissolved and to facilitate extraction of the polyester from said solvent system and recycling of the solvent system. It is typically the case that the second solvent system in this embodiment comprises solvents selected from: arenes; cycloalkanes; aldehydes; ketones; esters; cyclic ethers or combinations thereof The arenes are typically substituted henzenes, typically alkyl or alkoxy henzcncs.

Examples of alkyl benzenes include p-cymene and typical examples of alkoxy benzenes include dimethoxybenzene. anethole, vanillyl butyl ether and methoxyphenyl butanone.

It is often the case that the aldehydes used as the second solvent system comprise a solvent selected from: benzaldehyde; anisaldehyde; phenylacetaldehyde; cinnamaldehyde; phenyl butenal; or combinations thereof.

Where ketones are used in the second solvent system, these are typically selected from: menthone; fenchone; earvone; aeetophenone; methoxyacetophenone; propiophenone; butyrophenone; or combinations thereof The esters used in the second solvent system often comprise alkyl henzoatcs such as: methyl henzoate; ethyl benzoate; propyl benzoate; isopropyl benzoate; butyl benzoate; isobutyl benzoate; sec-butyl benzoate; tert-butyl benzoate; hexyl benzoate. The esters may also be selected from: amy! benzoate; isoamyl benzoate; acetyl tributyl citrate; menthyl acetate; fenchyl acetate; bornyl acetate; gamma-butyrolactone; gamma-valerolactone; gamma-caprolactone; aipha-angelicalactone; phenyl acetate; henzyl acetate; henzyl propionate; henzyl hutyrate; henzyl isohutyrate; henzyl 2-methylbutyrate; henzyl valerate; henzyl henzoate; methyl phenylacetate; methyl cinnarnate; ethyl cinnamate; propyl cinnamate; cinnamyl acetate; cinnamyl propionate; phenyl benzoate; anisyl acetate; 2-phenethyl 2-methyihutyrate; methyl salieylate; ethyl salicylate; methyl anisate; ethyl anisate; or combinations thereof. A typical cyclic ether which may be used in the second solvent system is cineo!e.

The second solvent system may also make use of supercritieal CO2 as a solvent.

It is often the case that the second solvent systeni comprises a low chain aromatic alkyl ester. cinnamate ester or combinations thereof. ffi particular. methyl and/or ethyl henzoate are often used in the second soh'ent system. The inventors have lound that these solvents are not only excellent solvents for polyester, hut also are common ingredients in foods and therefore do not pose a risk to end users of packaging containing trace quantities of these compounds.

In a second embodiment of the invention, the first solvent system and the second solvent system are the same. In this situation the second temperature is greater than the first temperature. The solvent system is selected so that, at the first temperature, the solvent system dissolves dyes hut does not substantially dissolve polyester and at the second temperature, which is typically higher than the first temperature, the solvent system dissolves polyester. This allows one solvent to be used to remove dyes and dissolve the polyester. This simplifies the polyester extraction process.

It is typically the case that the first and second solvent systems in this embodiment comprise solvents selected from: arenes; cycloallanes; aldehydes; ketones; esters; cyclic ethers or combinations thereof.

The arenes are typically substituted benzenes. typically alkyl or alkoxy benzenes.

Examples of alkyl benzenes include p-cymene and typical examples of alkoxy benzenes include dimethoxybenzene, anethole. vanillyl butyl ether and methoxyphenyl butanone.

It is often the ease that the aldehydes used as the second solvent system comprise a solvent selected from: henzaldehyde; anisaldehyde; phenylacetaldehyde; cinnamaldehyde; phenyl butenal; or combinations thereof.

Where ketones are used in the first and second solvent systems, these are typically selected from: menthone; fenchone; carvone; acetophenone; methoxyacetophenone; propiophenone; butyrophenone; or combinations thereof The esters which may be used in the second solvent system are typically selected from: acetyl trihutyl citrate; menthyl acetate; fenchyl acetate; bornyl acetate; gamma-butyrolactone; ganmia-valerolactone; gamma-caprolactone; aipha-angelicalactone; alkyl benzoate; methyl benzoate; ethyl benzoate; propyl benzoate; isopropyl benzoate; butyl benzoate; isohutyl henzoate; sec-hutyl henzoate; tert-hutyl hentoate; amyl henzoate; isoamyl henzoate; hexyl henzoate; henzyl acetate; henzyl propionate; henzyl hutyrate; henzyl isobutyrate; benzyl 2-methylbutyrate; benzyl valerate; benzyl benzoate; methyl phenylacetate; methyl cinnamate; ethyl cinnamate; propyl cinnamate; cinnamyl acetate; cinnamyl propionate: pheny henzoate: anisy acetate; 2-phenethyl 2-methylbutyrate; methyl salicylate; ethyl salicylate; methyl anisate; ethyl anisate; or combinations thereof. Typical cyclic ethers include cineole.

Another solvent system which may he used as the first and second solvent systems is supercritical CO2.

It is often the case that the first and second solvent systems comprise a low chain aromatic alkyl ester or cinnamate ester or combination thereof. in particular. methyl and/or ethyl benzoate are often used in the second solvent system. These solvents have been found by the inventors to show excellent versatility in dissolving both dyes and polyester at different temperatures.

It is usually the case that the first temperature is in the range 70 °C -120°C, more typically 80°C -110°C or even more typically 90°C -100°C. The second temperature is typically 100°C -200°C, more typically 110°C -180°C and even more typically 120°C -150°C.

Whilst there is no particular restriction on the period of time that a packaging is exposed to the solvent systems of the invention, this period may he in the range 30 minutes to 4 hours, more typically in the range 45 minutes to 3 hours, or even more typically in the range I to 2 hours. These durations minimise the amount of time required to dissolve a sufficient proportion of the dyes or polyester against the energy required to sustain the temperature of the solvent systems for said period of time.

The process is usually conducted at atmospheric pressure. The process can he conducted under pressurised conditions, in order to achieve a superheated solvent system with higher temperatures than those available at standard pressure and therefore faster rates of reaction. However, this often requires specific reaction chambers capable ci withstanding high pressure and intensive heating. This requires a greater input of energy and does not usually improve the energy efficiency of the process.

Not all colouring agents are readily solulie. For example. carbon black is sometimes used to provide a black colour to packaging which consists essentially of non-diamond carbon. This and other inorganic materials are insoluble in most solvent systems.

Accordingly, the process may include a filtration step wherein the dissolved polyester is filtered to remove fine particles of inorganic and other insoluble matter.

Once the polyester has been dissolved it is typically extracted from the second solvent system by evaporating the solvent. This can be done using elevated temperatures and/or using vacuum extraction to remove the solvent lo leave the dye-free polyester.

It is often the case that the removed second solvent system is condensed arid reused in the process. The removed second solvent system may be used either as a source of the Iirst solvent system in step a) and/or as a source of the second solvent system which is used in step d). Typically, and necessarily where the first scñvent system is not the same as the second solvent system. the second solvent system is reused as the second solvent system in step d). This reduces the amount of waste solvent generated in the process and minimises the amount of solvent required for the reaction.

The first solvent system is also typically isolated from the dyes using elevated temperatures and/or vacuum extraction to remove the first solvent system. This can be condensed and reused in the process to further minimise the amount of waste solvent generated by the process. This also isolates the dye materials originally present in the packaging which can themselves be reused, for instance in the immufacture of new clothes.

The first solvent system is often recycled and reused as the first solvent system in step a) and/or as the second solvent system used in step d) where the first and second solvent systems are the same. Typically, the first solvent system is reused as the first solvent system in step a). This recycling of reagents reduces the reliance of the process on new feed of solvent and reduces the amount of solvent consumed.

The invention will now be described with reference to the following figures, drawings

and examples.

Brief Description of the Drawings

Figure 1 shows a schematic diagram of a typical embodiment of the process of the invention wherein the first solvent system and the second solvent system are the same.

Figure 2 shows a schematic diagram of a typical embodiment of the process of the invention wherein the first solvent system and the second solvent system are different.

II

Description

Figure 1 shows an example of the recycling process of the invention, wherein the solvent used for both the dye extraction step and polyester extraction steps is methyl henzoate. Packaging containing polyesters are comminuted and mixed with an excess of mcthyl bcnzoatc and thc rcaction mixture is hcatcd to a tcmpcraturc in the range 90°C to 100°C for approximately 10 minutes in step i). The reaction material is then liltered and the dye containing methy' henzoate solution is isolated from the polyester mixture in step ii). The dye solution is evaporated under vacuum to separate the methyl benzoate solvent from the dissolved dyes in step vi). The extracted methyl benzoate is then available for recycling into the initial reaction vessel in step vii) or can be incorporated into the reaction mixture in step viii).

The polyester mixture is then reacted with methyl benzoate at a temperature of 120°C to 130°C for two hours until all at least 95% of the polyester has been dissolved in step iii). The resulting mixture is then filtered in step iv) to separate the methyl benzoate I polyester mixture from the remaining insoluble impurities. The polyester is the isolated by evaporating the methyl bcnzoatc under vacuum in step v). The evaporated methyl henzoate is condensed and can then he reintroduced into the reaction mixture at step vii) or alternatively can he introduced into the reaction mixture at step viii).

Figure 2 shows an example of the recycling process of the invention wherein the solvent used to extract the dyes is different to the solvent used to extract the polyester from the packaging. Packaging containing polyester are comminuted and mixed with an excess of ethyl acetate and the reaction mixture is heat to a temperature in the range 90°C to 100°C for approximately 10 minutes in step i). The reaction material is then filtered and the dye containing ethyl acetate solution is isolated from the polyester mixture in step ii). The dye solution is evaporated under vacuum to separate the ethy' acetate solvent from the dissolved dyes in step vi). The extracted ethyl acetate is then available for recycling into the initial reaction vessel in step vii).

The polyester mixture is then treated with methyl benzoatc at a temperature of 120°C to 130°C for two hours until all at least 95% of the polyester has been dissolved in step iii). The resulting mixture is then filtered in step iv) to separate the methyl benzoate I polyester mixture from the remaining insoluble impurities. The polyester is the isolated by evaporating the methyl benzoate under vacuum in step v). The evaporated methyl henzoate is condensed and can then he reintroduced into the reaction mixture in step viii).

Examples

Example 1 -Dissolution of bottle grade poly(ethylene terephthalate) (PET) in ethyl benzoate Ethyl benzoate (>99%, Sigma Aldrich, 250mL) was placed in a 1 litre round bottomed flask equipped with reflux condenser and magnetic stirrer and heated to 120°C with stirring on a hot plate. Mixed post-consumer PET chip from plastic bottles (lOg.

mixture of colourless, blue and green) was added to the solvent and the mixture was stilTed for 30 minutes at 120°C. Over this period, the solvent was observed to turn green in colour owing to the leaching of dycstuffs. The PET was heavily permeated and swollen by the solvent but did not dissolve to a significant extent. The mixture was then heated to in the range 180-200°C for a further 2 hours, with stilTing, over which period the solid PET was observed to entirely dissolve, yielding a clear green solution. Heating was discontinued and the solution was allowed to cool to room temperature, whereupon it solidi lied into a waxy polymer-solvent gel phase of a pale blue-green colour. This material was transferred to a filter funnel and washed with a further 250mL cold ethyl benzoate. The solid was then triturated with a large excess of cold 50% ethanol to remove solvent and dyestuffs. This yielded a pale greenish filtrate and a damp white semicrystalline solid (l4.6g) which was ground to a powder and dried at room temperature in vacew over MgSO4 to yidd 9.62g of white solid.

Claims

Claims 1. A process for extracting p&yester Irom packaging containing one or more dyes comprising the steps of: a) contacting the packaging with a first solvent system to form a mixture; b) maintaining the mixture at a first temperature for a first period of time until substantially all of the dye has been dissolved; c) removing the first solvent system containing the dissolved dye; d) contacting the remaining mixture with a second solvent system in order to dissolve the polyester; e) maintaining the remaining mixture at the second temperature for a second period of time until substantially all of the polyester has been dissolved; 1) removing the second solvent system containing the dissolved polyester; and g) recovering the polyester from the second solvent system; wherein the first and second solvent systems are each lood grade solvents wherein the second temperature is greater than the first temperature when the first solvent system and the second solvent system are the same.
2. A process according to claim 1, wherein the first solvent system is selected from: cycloalkenes; ketones; esters; carbonates; or combinations thereof or combinations thereof.
3. A process according to claim 2, wherein the cycloaWenes comprise limonene.
4. A process according to claim 2. wherein the ketones comprise cyclopentanone; acetone; or combinations thereof.
5. A process according to claim 2, wherein the esters are ailcyl esters.
6. A process according to claim 5, wherein the alkyl esters arc selected from: ethyl acetate; propyl acetate: hutyl acetate; isohutyl acetate: tert-huty acetate; amyl acetate; isoamyl acetate; ethyl propionate; ethyl butyrate; ethyl isobutyrate; propyl propionate; propyl butyrate; butyl butyrate; isobutyl butyrate; butyl isobutyrate; isobutyl isobutyrate; ethyl valcratc; propyl vaicrate; butyl valerate; amy! valerate; or combinations thereof.
7. A process according to claim 6. wherein the first solvent system comprises ethyl acetate.
8. A process according to claim 2, wherein the carbonates are selected from dimethyl carbonate. diethyl carbonate or combinations thereof.
9. A process according to any preceding c!aim. wherein the second solvent system comprises solvents selected from: arenes; cychc ether: aldehydes; ketones; esters: or combinations thereof.
10. A process according to claim 9, wherein the arenes are substituted benzenes.
11. A process according to claim 10, wherein the substituted henzenes are alkyl and/or alkoxy benzenes.
12. A process according to claim II, wherein the alkyl henzene is p-cymene.
13. A process according to c!aim 11, wherein the alkoxy benzenes are se!ected from: dimethoxybenzene, anethole. vanil!y! butyl ether. methoxyoheny! butanone, or combinations thereof.
14. A process according to claim 9. wherein the cyc!ic ether is cineole.
15. A process according to claim 9. wherein the aldehydes comprise a so!vent selected from: benzaldehyde; anisaldehyde; phenylacetaldehyde; cinnamaldehyde; pheny! butenal; or combinations (hereof.
16. A process according to daim 9. wherein the ketones are selected from: menthone; fenchone; carvone; acetophenone; methoxyacetophenone; propiophenone; butyrophenone; or combinations thereof.
17. A process according to claim 9. wherein the esters are selected from: acetyl tributyl citrate; menthyl acetate; lenchyl acetate; hornyl acetate; gamma-hutyrolactone; gamma-valemlactone; gamrna-caprnlactone; alpha-angelicalactone; methyl henzoatc; ethyl henzoate; propyl henzoate: isopropyl henzoate: hutyl henzoate: isohutyl benzoate; sec-butyl benzoate; tert-butyl benzoate; amyl benzoate; isoamyl benzoate; hexyl henzoate; henzy acetate; henzyl propionate; henzyl hutyrate; henzy isobutyrate; benzyl 2-methylbutyrate; benzyl valerate; benzyl benzoate methyl phenylacetate; methyl cinnamate; ethyl cinnamate; propyl cinnamate; cinnamyl acetate; cinnamyl propionate; phenyl benzoate; anisyl acetate; 2-phenethyl 2-methylhutyrate: methyl salicylate; ethyl salicylate: methyl anisate: ethyl anisate; or combinations thereof.
18. A process according to claim 17, wherein the esters are selected from: methyl henzoate; ethyl henzoate; propyl henzoate; isopropyl henzoate; huty henzoate; isohutyl henzoate: sec-hutyl henzoate; tert-hutyl henzoate: amyl henzoate: isoamyl benzoate; hexyl benzoate; methyl cinnamate; ethyl einnamate; propyl cinnamate; cinnamyl acetate; cinnamyl propionate; phenyl benLoate; or combinations thereof.
19. A process according to claim 18, wherein the esters are alkyl esters.
20. A process according to claim 19. wherein the alkyl esters comprise methyl and/or ethyl henzoate.
21. A process according to claim 1. wherein the first and second solvent systems are the same and both comprise solvents selected from: arenes; cyclic ethers; aldehydes; ketones; esters: or combinations thereof.
22. A process according to claim 21. wherein the arenes are substituted benzenes.
23. A process according to claim 22, wherein the substituted henzenes are alkyl and/or alkoxy benzenes.
24. A process according to claim 23, wherein the alkyl benzene is p-cymene.
25. A process according to claim 23, wherein the alkoxy henzenes are selected from: dimethoxyhenzene, anethole. vanillyl hutyl ether, methoxyohenyl hutanone, or combinations thereof.
26. A process according to claim 21, wherein the cyclic ether is cineole.
27. A process according to claim 21, wherein the aldehydes comprise a solvent selected from: benzaldehyde; anisaldehyde; phenylacetaldehyde; cinnamaldehyde; phenyl hutenal: or combinations thereof
28. A process according to claim 21, wherein the ketones are selected from: menthone; fenchone; carvone; aeetophenone; methoxyacetophenone; propiophenone; hutyrophenone; or combinations thereof.
29. A process according to claim 21, wherein the esters are selected from: acetyl tributyl citrate; menthyl acetate; fenchyl acetate; bornyl acetate; gamma-butyrolactone; gamma-valerolaetone; gamma-caprolaetone; aipha-angelicalactone: alkyl henzoate; methyl benzoate; ethyl benzoate; propyl benzoate; isopropyl benzoate; butyl benzoate; isobutyl benzoate; sec-butyl benzoate; tert-butyl benzoate; amyl benzoate; isoamyl benzoate; hexyl benzoate; benzyl acetate; benzyl propionate; benzyl butyrate; benzyl i sohutyrate; henzy 2-methylhutyrate; henzyl valerate; henzyl henzoate methyl phenylacetate; methyl cinnamate; ethyl cinnamate; propyl cinnamate; cinnarnyl acetate; cinnamyl propionate; phenyl benzoate; anisyl acetate; 2-phenethyl 2-methylbutyrate; methyl salicylate; ethyl salicylate; methyl anisate; ethyl anisate; or combinations thereof.
30. A process according to claim 29, wherein the esters are selected from: methyl benzoate; ethyl benzoate; propyl benLoate; isopropyl benzoate; butyl benzoate; isohutyl henzoate: sec-hutyl henzoatc; tert-hutyl hcnzoate: amyl hcnzoate: isoamyl benzoate; hexyl benzoate; methyl cinnamate; ethyl cinnamate; propyl cinnamate; cinnamyl acetate; cinnamyl propionate; phenyl benzoate; or combinations thereof.
31. A process according to claim 30, wherein the esters are alkyl esters.
32. A process according to daim 31, wherein (lie esters comprise methyl and/or ethyl henzoatc.
33. A process according to my preceding claim, wherein the polyester is selected from: Polyglycolic acid (PGA), PcAylaetic acid (PLA), Polycaprolactonc (PCL).Polyethylene adipate (PEA). Polyhydroxyalkanoate PHA), Polyethylene terephthalate WET), Polybutylene terephthalate PBT). Polytrimethylene terephthalate IPTT), Polyethylene naphthalate (PEN) or combination thereof.
34. A process according to claim 34, wherein the polyester is polyethylene terephthalate.
35. A process according to any preceding claim, wherein the packaging comprises food packaging.
36. A process according to any preceding claim, wherein the packaging comprises black packaging.
37. A process according to any preceding claim, wherein the packaging comprises bottles.
38. A process according to claim any preceding claim, wherein the first temperature is in the range 70°C -120°C.
39. A process according to claim 38. wherein the first temperature is in the range 90°C -100°C.
40. A process according to any preceding claim, wherein the second temperature is in the range 70°C -200°C.
41. A process according to daim 40, wherein the second temperature is in the range 80°C -150°C.
42. A process according to claim 41, wherein the second temperature is in the range 90°C -100°C.
43. A process according to any preceding claim, wherein the second temperature is greater than the first temperature.
44. A process according to any preceding daim, further comprising the step of recovering the dye from the first solvent system.
45. A process according to claim 44, wherein at least some of the first solvent system is reused as the first solvent system in step a) and/or wherein the first solvent system is reused as the second solvent system in step d).
46. A process according to claim 45. wherein the first solvent system is reused as the first solvent system in step a).
47. A process according to any preceding claim, wherein the second solvent system is reused as the first solvent system in step a) andlor wherein the second solvent system is reused as the second solvent system in step d).
48. A process according to claim 47, wherein the second solvent system is reused as the first solvent system in step d).
49. A process according to any preceding claim, wherein the first and/or the second solvent system are homogeneous.
50. A process according to any preceding claim, wherein the first period of time is in the range 5 minutes to 120 minutes.
51. A process according to claim 49, wherein the first period of time is in the range S minutes to 20 minutes.
52. A process according to any preceding claim, further comprising a filtration step to remove undissolved impurities from the second solvent system comprising the dissolved polyester.
53. A process according to any preceding claim, wherein the packaging is black packaging.
54. A process as described in the description. examples and drawings disclosed herein.