WO2014047620A1 - Removal of color from thermoplastics - Google Patents

Abstract

Process of decolorizing dyed thermoplastics are provided that includes intermixing a dyed thermoplastic with a decolorization agent solution at a temperature that is below the melting temperature for the thermoplastic. The processes for the first time are capable of removing substantial portions of dye from the thermoplastic providing a material that is suitabl for recycling processes and use in subsequent recycled articles.

Description

REMOVAL OF COLOR FROM THERMOPLASTICS

CROSS REFERENCE TO RELATED APPLICATIONS

[0001] This application depends from and claims priority to U.S. Provisional Application No: 61/704,871 filed September 24, 2012, the entire contents of which are incorporated herein by reference.

FIELD OF THE INVENTION

[0002] The invention relates to the decoloration of plastic materials. Embodiments of the invention include methods for removing color from thermoplastic materials. Specific methods are provided for the removal of coloration from polyethylene terephthalate

BACKGROUND OF THE INVENTION

10003J Ί Tiermop!astics are used on a large scale for the manufacture of bottles such as those extensively used to package beverages including carbonated soft drinks, beer, or mineral water. Many bottle manufacturers prefer using colored bottles. Typical bottle colorations include greens, reds, yellows, browns, and mixtures of colors.

[0004] During manufacture, if the eventual bottle is to be colored, one or more dyes are typically admixed with thermoplastic granules charged to the hopper of the injection molding machine used to make the bottle preform. For this purpose the colorant or mixture of colorants can be added as a solid concentrate or in powder form or as a dispersion in a liquid carrier. Additives such as UV filters, oxygen absorbers, antimicrobial agents, antioxidants, light stabilizers, optical brighteners, processing stabilizers, or flame retardants, among others may also be added to the thermoplastic molding composition at or around the same time.

[0005] Recent processes of providing coloration to a thermoplastic involve infusing a thermoplastic material with a dye in a dye bath such as is found in U.S. Patent No. 7,175,675, or by spraying a colorant onto the surface of the article as described in U.S. Patent No. 6,994,735. Upon formation of the final product, the colored layer is stretched to l ess than 1 mm in depth, but still provides sufficient coloration to provide a desirable packaging for sale to a consumer.

[0006] Unfortunately, the use of color in recyclable thermoplastics presents numerous difficulties for future uses. The presence of the dye in the thermoplastic material is difficult to remove so as to allo subsequent use in future applications requiring clear or non-colored recycled material. Many attempts have been made to remove this color. For example, the dyes have been attempted to be removed by washing steps such as a caustic wash, by heating to damage the dye stnicture, or by exposing the material to an energy source such as ultraviolet (UV) light. To date, these methods have been unable to remove sufficient coloration of the recycled material for it to be useful. For example, the process of U.S. Patent Application Publication No. 2006/0148914 shows some color change, but as is described therein, full color is not removed from the material, Other attempts at removing color resulted in a yellow tint to the material that is non-removable, thus, contaminating any recycled material and limiting its use in only future colored articles.

[0007 J As such, there is a long felt need for processes of removing color from thermoplastics during recycling such that the output stream is capable of being used for applications requiring color free materials.

SUMMARY OF THE INVENTION

[0008] The following summary of the invention is provided to facilitate an understanding of some of the innovative features unique to the present invention and is not intended to be a full description. A full appreciation of the various aspects of the invention can be gained by taking the entire specification, claims, drawings, and abstract as a whole.

[0009] While recycling of post-consumer plastic materials has been practiced for many years, the presence of dyes in colored plastics regularly confounds the recycling process when the recycled material stream is intended to be subsequently used in the manufacture of clear materials. The present in vention provides for the first time effecti ve methods of removing color from thermoplastics, illustratively color infused thermoplastics. As such, it is a primary object of the invention to decolorize thermoplastic or other materials. A process includes providing a thermoplastic material in solid form, the thermoplastic comprising one or more dyes infused into the thermoplastic material, the dye imparting color to the thermoplastic material; mixing, immersing, or coating the thermoplastic material with a decolorizing agent solution for a decolorization time of 10 minutes or less and at a decolorization temperature below the melting temperature of the thermoplastic, the solution comprising one or more decolorizing agents; and decolorizing the thermoplastic material by the mixing step thereby forming a decolorized thermoplastic material. A decolorization temperature in many embodiments of the invention may be from 60 degrees Celsius to 98 degrees Celsius, optionally from 81 and 91 degrees Celsius. The inventors have discovered that decolorization agents according to Formula I:

Rⁱ---[(0(CH2)_ffi)r₁--]OR² ( ! )

wherein R² and R¹ are each independently H or a Ci-n alkyl, benzyl, benzoyl, or phenyl; n is 1 , 2 or 3; and m is any value from 1 to 35 are particularly useful in removing color from a colored thermoplastic, in many embodiments, R¹ is an ethyl, propyl or butyl. Optionally, m is 2, 3 or 4. Optionally, n is 2 or 3. In particular embodiments, a decolorization agent according to Formula I is 2-butoxyethanol. A thermoplastic is optionally polyethylene terephthalate or polycarbonate.

[0010] In other embodiments, a process includes providing a thermoplastic material in solid form comprising one or more dyes infused into the material, where the dye imparts color to the thermoplastic material; mixing the thermoplastic material with a decolorizing agent solution for a decolorization time and at a decolorization temperature below the melting temperature of the thermoplastic, the solution comprising one or more decolorizing agents, said decolorizing agents selected from the group comprising an oxidizing agent, a reducing agent, or combinations thereof; and decolorizing the thermoplastic material by the mixing step thereby forming a decolorized thermoplastic material. An oxidizing decolorization agent is optionally a hypohalite compound, optionally sodium hypochlorite. A decolorization agent is optionally an organic peroxide or an inorganic peroxide alone or combined with a catalyst. A decolorization agent is optionally a peroxide of Formula I I:

R³ O O IV (li)

where R³ and R are each independent of the other a hydrogen, alkyl, aryl, heteroaryl, acyl, silicon-containing group, lithium, germanium-containing group, phosphorus-containing group, titanium-containing group, organometallic compound, carbonate, carbamate, or a repeating unit of a polymeric structure. A decolorization agent is optionally a reducing agent selected from the group consisting of zero valent iron, a bisulfite, sodium borohydride, lithium borohydride, potassium borohydride, thiourea dioxide, polymethylhydrosiloxane, and hydrazine, A decolorization temperature in many embodiments of the invention may be from 60 degrees Celsius to 98 degrees Celsius, optionally from 81 and 91 degrees Celsius. A decolorization time is optionally 10 minutes or less, optionally 1 to 5 minutes, in some embodiments, the thermoplastic is irradiated with UV spectrum light in the presence or absence of the decolorization agent.

[0011] In other embodiments of the invention a process for forming a decolorized thermoplastic includes providing a thermoplastic material in solid form comprising one or more dyes infused into said material, said dye imparting color to said material; mixing the thermoplastic material with a decolorizing agent solution for a decolorization time and at a decolorization temperature below the melting temperature of the thermoplastic, the solution comprising one or more decolorizing agents, the decolorization agent comprising an agent having a structure of Formula 111:

R⁵-[CO-G-R⁶]x (III) where R⁵ and R⁶ are each independently: a H, substituted or unsubstituted linear, branched, cyclic, or combination CMS alkyl, C1-18 alkenyl, Ci-is alkynyl, or phenyl; and where x is any number from 1 -4; and decolorizing the thermoplastic material by the mixing step thereby forming a decolorized thermoplastic material. Optional decolorization agents according to Formula III are plasticizers. Optionally, a plasticizer is bis(2-ethylhexyl) phthalate, butyl benzyl phthalate, diisodecyl phthalate, di-n-octyl phthalate, diisooctyl phthalate, diisobutyl phthalate, or di-n-hexyi phthalate, In some embodiments, a decolorization agent is an acetate ester, A. second decolorization agent is optionally provided where a second decolorization agent is optionally of Formula I wherein R² and R¹ are each independently H or a Ci-is alkyl, benzyl, benzoyl, or phenyl; n is 1 , 2 or 3; and m is any value from 1 to 35 are particularly useful in removing color from a colored thermoplastic, In many embodiments, R^! is an ethyl, propyl or butyl. Optionally, m is 2, 3 or 4. Optionally, n is 2 or 3, In particular embodiments, a decolorization agent according to Formula I is 2-butoxyethanol. A decolorization temperature in many embodiments of the invention may be from 60 degrees Celsius to 98 degrees Celsius, optionally from 81 and 91 degrees Celsius. A decolorization time is optionally 10 minutes or less, optionally 1 to 5 minutes.

[0012J In some embodiments, a process of forming a decolorized polyethylene terephthalate includes mixing polyethylene terephthalate thermoplastic material in solid form with a decolorizing agent solution, the polyethylene terephthalate material including one or more dyes mfused into the material imparting color to the thermoplastic material; and decolorizing the polyethylene terephthalate material by mixing the thermoplastic material with a decolorizing agent solution for a decolorization time and at a decolorization temperature below the melting temperature of the polyethylene terephthalate, the solution including one or more decolorizing agents thereby forming a decolorized polyethylene terephthalate material. The dye is the PET is optionally penetrating a surface of the PET to a depth of less than 1 mm, absent a dye at a depth greater than 1 mm. The dye is optionally a thermoliable dye or unstable dye. A dye is optionally an azo or quinone dye. A dye is optionally disperse red 1. A decolorization agent in many embodiments is of Formula I: wherein R² and R¹ are each independently H or a Ci-is alkyl, benzyl, benzoyl, or phenyl; n is 1, 2 or 3; and m is any value from 1 to 35 are particularly useful in removing color from a colored thermoplastic. In many embodiments, R¹ is an ethyl, propyl or butyl. Optionally, m is 2, 3 or 4. Optionally, n is 2 or 3. A decolorization agent is optionally an aqueous solution of decolorization agent. In some embodiments, the PET is heated to a decolorization temperature for a decolorization time subsequent to or simultaneous with the step of mixing. A decolorization temperature is optionally less than 100 degrees Celsius, optionally from 81 to 91 degrees Celsius.

[0013] The processes of the in vention substantially decolorize thermoplastic materials in a rapid and effective process that is suitable for use in recycling post-consumer or other thermoplastic materials.

BRIEF DESCRIPTION OF THE DRAWINGS

(0014] FIG. 1 illustrates transmission profiles of Disperse Red I colored PET before and after decolorization using a oxidizing decolorization agent and UV light according to one embodiment of the invention;

[0015] FIG. 2 illustrates transmission profiles of polycarbonate colored or decolorized according to one embodiment of the invention;

(0016] FIG. 3 illustrates transmission profiles of Disperse Red dyed PET colored or decolorized according to one embodiment of the invention:

[0017] FIG. 4A illustrates transmission profiles of PET colored or decolorized according to one embodiment of the invention using a phthalate decolorization agent according to Formula III;

(0018] FIG. 4B illustrates transmission profiles of PET colored or decolorized according to one embodiment of the invention using a acetate ether decolorization agent according to Formula III;

[0019] FIG. 5 A illustrates transmission profiles of PET colored Disperse Red 1 or decolorized using various decolorization agent concentrations (according to Formula II) or irradiation alone according to one embodiment of the invention;

[0020] FIG. 5B illustrates transmission profiles of PET colored with Disperse Orange 47 or decolorized using various decolorization agent concentrations (according to Formula II) or irradiation alone according to one embodiment of the invention;

[0021] FIG. 5C illustrates transmission profiles of PET colored with Disperse Yellow 82 or decolorized using various decolorization agent concentrations (according to formula II) or irradiation alone according to one embodiment of the invention;

[0022] FIG. 6A illustrates the transmittance spectrum prior to decolorization of an exemplar}' set of bottles infused with solvent blue 35 for 0 (control), 5, 10, and 20 seconds; and [0023] FIG. 6B illustrates the transmittance spectaim of an exemplary set of bottles colored with solvent red 447 for 0 (control), 5, 10, and 20 seconds prior to decolorization,

DETAILED DESCRIPTION OF EMBODIMENTS OF THE INVENTION [0024] The following description of particular embodiment(s) is merely exemplary in nature and is in no way intended to limit the scope of the invention, its application, or uses, which may, of course, vary. The invention is described with relation to the non-limiting definitions and terminology included herein. These definitions and terminology are not designed to function as a limitation on the scope or practice of the invention but are presented for illustrative and descriptive purposes only. While the processes are described as an order of individual steps or using specific materials, it is appreciated that described steps or materials may be interchangeable such that the description of the invention includes multiple parts or steps arranged in many ways as is readily appreciated by one of skill in the art.

[0025] The processes provided are useful for removal of color from thermoplastics such as PET, as one example. Currently, multi-colored plastic bottles and the like are not easily or cost effectively recyclable because in part it is not economically viable to do so. Coloring agents (e.g. dyes) present in waste bottles to be recycled causes the recycling value of such bottles to be quite low. The processes provided increase the economic value of such recycled materials.

[0026] The invention has utility as a method for removing color from thermoplastic materials. Although much of the invention is described with respect to polyethylene terephthalate (PET), many embodiments are similarly useful for other thermoplastic types.

[0027] A process of decolorizing a thermoplastic material is provided including optionally providing or otherwise obtaining a thermoplastic material in solid form, wherein the thermoplastic material is colored by one or more dyes admixed with the thermoplastic material, infused into the thermoplastic material, or coated on the thermoplastic material, A colored thermoplastic material is optionally at least a portion of post-consumer material. Optionally, a colored thermoplastic material is entirely post consumer material. A process of decolorizing a thermoplastic material includes mixing the colored solid thermoplastic material with a decolorizing agent solution including one or more decolorizing agents whereby the decolorizing agent alone or in combination with one or more environmental conditions (e.g. heat, UV light) produces a decolorized thermoplastic material.

[0028] A process includes obtaining or providing a colored thermoplastic material. A thermoplastic material is optionally one or more of polypropylene (PP), polyethylene terephthalate (PET), polybutylene terephthalate (PBT), polycarbonates (PC), polyethylene (PE), poiylactic acid (PLA), nylon, PET copolymers, acrylics, Surlyn™, polyethylene naphthalate (PEN), poiyamides, polycarbonate co-polymers, elastomeric polymers - thermoplastic elastomers, thermoplastic urethanes, poly urethanes, acrylic co-polymers, acrylonitrile butadiene styrene, or other thermoplastics. In particular embodiments, a thermoplastic is polyethylene terephthalate (PET).

[0029 J A colored thermoplastic is optionally that formed by any of several processes, in some embodiments, a colored thermoplastic is formed by the processes of U.S. Patent Nos.i 6,733,543; 6,749,646; 7,175,675; 7,504,054; 6,959,666; 6,949,127; 6,994,735; 7,094,263; 8,206,463; or 7,921,680. In some embodiments, a colored thermoplastic is formed as described in U.S. Patent Application Publication Nos.: 2008/0067124; 2009/0297830; or 2009/0089942. in particular embodiments of the process, a colored thermoplastic is formed by infusion of one or more dyes into the surface of the thermoplastic material to a depths of 0.1-2 mm. Upon forming a container such as by compression molding, injection molding, rotational molding, extrusion, injection and extrusion blow molding, or casting of the thermoplastic into a final shape, the dye is present to a depth of 0.01 to 1 mm. As such, the process provided are used to remove color from a dye that is from 0.01 to lmm in depth or more, or any value or range therebetween. Optionally, a dye depth is from 0.01 to 0.5 mm. Optionally, a dye depth is from 0.05 to 0,2 mm, [0030] A colored thermoplastic is optionally formed by immersing the thermoplastic material into a liquid dye solution, or spraying a dye solution onto the surface of the thermoplastic material, for a time and at a temperature to allow some infusion of the dye into the surface of the thermoplastic material. The coloring temperature is appreciated to be below the melting temperature of the thermoplastic material. Illustratively, for a polycarbonate thermoplastic material a coloring temperature may be 90°C to 99°C. It is appreciated that thermoplastics that may have a lower heat distortion temperature may be dyed at a lower temperature. As one example, a coloring temperature of a polyurethane may be about 60°C. A coloring time is optionally less than one hour, preferably from 1 to 15 minutes, or any value or range therebetween.

[0031] During recycling, a colored thermoplastic is typically washed, flaked or pelletized, or reacted to constituents, re-polymerized and then pelletized and then supplied to a solid-state reactor, in the process of converting waste plastic into recyclable articles. In several embodiments, the colored thermoplastic is flaked to produce substantially uniform particles for efficient subsequent processing and prior to decolorization,

[0032] The dye that is altered or removed from a colored thermoplastic according to particular embodiments is a stable dye or an unstable dye. In some embodiments, a dye is an unstable dye. An unstable dye as defined herein is a dye that is chemically or structurally alterable by exposure to heat, light energy, or both. Several such dyes are known in the art. An unstable dye optionally includes azo type dyes or unstabiiized quinone dyes. Optionally, a dye is a static dye, photochromic dye or combinations thereof. As used herein, the term "static dye" means a dye that does not substantially change color upon exposure to (or being shielded from) ultraviolet (IJV) light. The term "photochromic dyes" as used herein and the claims means dyes that reversibly change color upon exposure to UV light, as is known to the skilled artisan.

[0033] Static dyes that may be included in a colored thermoplastic and by an inventive process removed or chemically altered include, for example, fabric dyes and disperse dyes as well as dyes that are known in the art as being suitable for tinting plastic articles, such as thermoplastic PET^' or polycarbonate articles. Examples of suitable disperse dyes include, but are not limited to, Disperse Blue #3, Disperse Blue #14, Disperse Yellow #3, Disperse Red #13 and Disperse Red #17. The classification and designation of the static dyes are recited herein in accordance with "The Colour Index", 3^rd edition published jointly by the Society of Dyes and Colors and the American Association of Textile Chemists and Colorists (1971), The term static dye as used herein optionally includes mixtures of static dyes.

[0034] Illustrative examples of static dyes include the water-insoluble azo, diphenylamine and anthraquinone compounds, illustrative examples include acetate dyes, dispersed acetate dyes, dispersion dyes and dispersol dyes, such as are disclosed in Colour Index, 3^rd edition, vol. 2, The Society of Dyers and Colourists, 1971 , pp. 2479 and pp. 2187-2743, respectively. Specific examples of dispersal dyes include Solvent Blue 59 (9,10-Anthracenedione, 1,4- his(ethylammo)-), Solvent Red 111 (9,10-Anthracenedione, l-(meihylamino)-), Solvent Yellow 160: 1 (3-(5-Chloro-2-benzoxazolyr)-7-(diethylamino)-2H-l -benzopyran-2-one), Disperse Orange 47 (lH-Indole-5-carboxylicacid,2-[2-(l ,5-ditiydro-3-methyl-5-oxo-l-phenyl-4H-pyrazol- 4-ylidene)ethylidene]-2,3-dihydro- 1 ,3,3-trimethyl-methyl ester), Disperse Yellow 3 (Acetamide, N-[4-[2-(2-b.ydroxy-5-methylphenyl)diazenyl]pb.enyl]-), Solvent Violet 26 (l,4-Diamino-2,3- diphenoxyanthraquinone), Disperse Red 1 (4-[(2-Hydroxyethyi)ethylamino]-4'- nitroazobenzene), and Solvent Green 28 (l,4-bis[(4.butylphenyl)amino]-5,8-dihydroxy-9,10- anthracenedione). Other dyes are illustratively those additional dyes found in U.S. Patent No. 7,175,675 and references cited therein.

[0035] In an inventive process, a colored thermoplastic material is mixed with a decolorizing agent solution including one or more decolorizing agents. A decolorization agent solution is optionally an aqueous solution, or a solution of one or more organic solvents or solutes. A decolorization agent solution is optionally entirely formed of a decolorization agent. In some embodiments, a decolorization agent solution includes water, a decolorization agent, and optionally one or more additives. An additive is illustratively one more surfactants or emulsifiers. A decolorization agent solution is optionally free of a dye prior to mixing with a colored thermoplastic. Optionally, a decolorization agent solution includes one or more secondary dyes wherein a secondary dye is any dye described herein, but of different dye chemical structure than that contained in the thermoplastic material to be decolorized. As such, a decolorization agent solution optionally serves to alter the color characteristics of a thermoplastic during a recycling process to yield a different output color.

|0036] A decolorization agent solution is optionally an aqueous solution wherein water is present in an amount of less than or equal to 98 percent by weight, optionally less than or equal to 80 percent by weight, optionally less than or equal to 75 percent by weight, in some embodiments, water is present in a decolorization agent solution in an amount of at least 50 or 51 percent by weight, optionally at least 60 percent by weight, and optionally at least 65 percent by weight. Water may be present in the decolorization agent solution in an amount ranging from 50 to 85 percent by weight or any value or range therebetween, with particular ranges being preferred. For example, water may be present in the decolorization agent solution in an amount from 50 (or 1) to 85 percent by weight, optionally 60 to 87 percent by weight, optionally in an amount of from 65 to 75 percent by weight, optionally 70 percent by weight. In some embodiments, water is present from 85 to 99 percent by weight, optionally 90 to 98 percent, optionally 95 to 98 percent by weight, optionally 98 percent by weight. The percent weights being based on the total weight of the decolorization agent solution. The water used is optionally deionized water or distill ed water the preparation of each of which is well known in the art, |0037] A decolorization agent is optionally an oxidizing agent, a free radical precursor, or a compound having the formula of Formula 1:

R^s---[(0(CH2)_m)n--]OR² (I)

wherein R² and R^! are each independently H or a CMS aikyl, benzyl, benzoyl, or phenyl; n is 1 , 2 or 3; and m is any value from 1 to 35. In some embodiments, m is 1 to 12. In some embodiments, m is 1. Optionally, R¹ denotes butyl and R² denotes H,

[0038 J An aromatic R¹ or R group of Formula I is optionally substituted with 1 to 5 groups selected from halo groups (e.g., chloro, bromo and fluoro), linear or branched C 3---C9 alkyl groups (e.g., methyl, ethyl, propyl, butyl, pentyl, hexyl, heptyl, octyl and nonyl), and aromatic groups (e.g., phenyl).

[0039] Specific examples of a decolorization agent solution according to Formula I include 2-methoxyethanol, 2-ethoxyethanol, 2-propoxyethanol, 2-isopropoxyethanol, 2-butoxyethanol, 2-phenoxyethanol. 2-beiizyloxyethanol, 2-(2-methoxyethoxy)ethanol, 2-(2- ethoxyethoxy)ethanoi, 2-(2-butoxyethoxy)ethanol, dimethoxyethane, diethoxyethane, and dibutoxyethane, or combinations thereof. [0040] in some embodiments, a process of decolorization involves removing the dye from the colored thermoplastic material. In such embodiments, the decolorization agent of Formula I is particularly well suited. In some embodiments, such non-destructive dye removal steps are the sole steps used to decolor the colored thermo lastic. In some embodiments, the non-destructive decolorization agents are used in combination with a destructive decolorization agent, either simultaneously or sequentially in either order. A destructive decolorization agent is an oxidizing agent, a reducing agent, a free radical precursor or combinations thereof.

0041 J in some embodiments, a decolorization agent is an oxidizing agent. An oxidizing agent is optionally a hypohalide such as a hypochlorite and salt forms thereof. A hypohaiide is optionally a hypochlorite. A hypochlorite is optionally a salt form such as that complexed with sodium or calcium, among others. In some embodiments, an oxidizing agent is a permanganate illustratively potassium permanganate, ammonium permanganate, calcium permanganate, sodium permanganate, or silver permanganate. Optionally, an oxidizing agent is a ferrioxalate, illustrati ely potassium ferrioxalate or sodium ierrioxalate, among others. Additional exemplary oxidizers include the mineral acids such as nitric acid or sulfuric acid.

[0042] In some embodiments, an oxidizing agent used as a decolorization agent is an organic or inorganic peroxide such as those useful as an oxidizing agent a free radical precursor or both. A peroxide has the structure of Formula II:

R³— O— O— R⁴ (II)

where R³ and R⁴ are each independent of the other a hydrogen, alkyl, aryl, heteroaryi, acyi, silicon-containing group, lithium, germanium-containing group, phosphorus-containing group, titanium-containing group, organometaliic compound, carbonate, carbamate, or a repeating unit of a polymeric structure. R³ and R⁴ may also be joined in a cyclic structure.

[0043] Without being limited to a particular theory, a peroxide may achieve decolorization of a colored thermoplastic by dissociation to form at least one radical. The resulting radical reacts with die dye(s) in the colored thermoplastic to decolorize or denature the dyes. Particular peroxides and other free radical precursors are illustrated in U.S. Patent Application Publication No. 2006/0148914. In some embodiments, a peroxide is combined with a catalyst to generate a free radical compound. A catalyst is any known catalyst, optionally iron such as ferrous iron (II), or a photocatalyst such as a semiconductor, optionally titanium dioxide.

[0044] In some embodiments, a decolorization agent is a compound of Formula III:

[0045] where R⁵ and ^B are each independently: a H, substituted or unsubstitiited linear, branched, cyclic, or combination Cus alkyl, CMS alkenyl, CMS alkynyl, or phenyl; and where x is any number from 1 -4. A substituent is optionally , O, or S. in some embodiments, x is 2, optionally with each acetate group bound to a different carbon or substituent on R⁵. R° is optionally a C2-C4 alkyl. Illustrative embodiments of decolorization agents according to Formula III are plasticizers, Specific illustrative examples of plasticizers are the phthalates. Specific illustrative examples of a decolorization agent according to Formula i l l include but are not limited to: a phthalate illustratively bis(2-ethylhexy[) phthalate, diisononyl phthalate, di-n-butyl phthalate, butyl benzyl phthalate, diisodecyl phthalate, diethyl phthalate, di-n-octyl phthalate, diisooctyi phthalate, diisobutyl phthalate, di-n-hexyl phthalate; an acetate ester illustratively methyl acetate, ethyl acetate, isopropyl acetate, butyl acetate, 2-methyipropyl ethanoate, and vinyl acetate.

[0046] Depending on the dye present in the substrate material, a reducing decolorization agent may be used, Examples of reducing agents include additives providing a source of hydrogen atom, hydride ion, or that function through nucleophilic attack. Illustrative examples of reducing agents useful as a decolorization agent include zero valent iron, bisulfite, odium borohydride, lithium borohydride, potassium borohydride, thiourea dioxide, pohTnethyihydrosiloxaiie, hydrazine, and the like.

[0047 J The decolorization agent is typically present in the decolorization agent solution in an amount of less than or equal to 30 percent by weight, optionally less than or equal to 25 percent by weight, optionally less than or equal to 20 percent by weight. The decolorization agent is optionally present in the solution in an amount of at least 10 percent by weight, optionally at least 15 percent by weight, optionally at least 17 percent by weight, The decolorization agent may be present in the solution in an amount ranging from 10 to 30 percent by weight or any value or range therebetween. For example, the decolorization agent is optionally present in the solution in an amount from 10 to 30 percent by weight, optionally from 15 to 25 percent by weight, optionally in an amount of from 17 to 20 percent by weight. The percent weights being based on the total w ei ht of the decolorization agent solution.

[0048] A decolorization agent solution optionally includes one or more decolorization agents. Optionally, a decolorization agent solution includes 1 , 2, 3, 4, 5, 6, or more decolorization agents. In some embodiments, when more than one decolorization agent is present in a decolorization agent solution, there may be decolorization agents of more than one type. Illustratively, a decolorization agent solution may include one or more decolorization agents of Formula II and one or more decolorization agents of Formula III. Other combinations of decolorization agents are optional ly used in combinations. [0049] While some embodiments may include a peroxide, free radical generator, oxidizing agent, or reducing agent as described herein, a decolorizing agent solution optionally excludes an oxidizing agent, a reducing agent, an agent of Formula I, and agent of Formula II I, a peroxide, or combinations thereof. As one example, a decolorization agent solution optionally excludes a peroxide, yet is still capable of achieving significant decolorization of a colored thermoplastic.

[0050] A decolorization agent solution optionally includes one or more emulsifiers. Illustrative examples of an emulsifier include ionic or non-ionic emulsifiers, or mixtures thereof, illustrative examples of an anionic emulsifier include: amine salts or alkali salts of carboxylic, sulfamic or phosphoric acids, for example, sodium lauryl sulfate, ammonium lauryl sulfate, lignosulfonic acid salts, ethylene diamine tetra acetic acid (EDTA) sodium salts, and acid salts of amines, such as, laurylamine hydrochloride or poly(oxy-l,2-ethanediyl), a-sulfo-omega-hydroxy ether with phenol l-(methylphenyl)ethyl derivative ammonium salts. An emulsifier is optionally an amphoteric emulsifier illustratively: lauryl sulfobetaine; dihydroxy ethylalkyl betaine; amido betaine based on coconut acids; disodium N-lauryl amino propionate; or the sodium salts of dicarbox lic acid coconut derivatives. Typical non-ionic emulsifiers include ethoxylated or propoxylated alkyl or aryl phenolic compounds, such as octyiphenoxypolyethyleneoxyethanol. A specific emulsifier used is diethyiene glycol.

[0051] An emulsifier is optionally present in a decolorization agent solution in an amount from 0 to 15 weight percent, optionally 7 to 15 weight percent, optionally 10 to 15 weight percent.

[0052] One example of a decolorization agent solution is LEVEGAL DLP available from Lanxess, LLC^', which is a pre-formulated mixture of a decolorization agent (polyglycol ether) with emulsifiers,

[0053] A decolorization agent solution is optionally at ambient temperature (approximately 25°C) or heated above ambient temperature. In some embodiments, a decolorizing process includes heating a colored thermoplastic alone or in the presence of a decolorization agent solution where heating is to a temperature below the melting temperature of the thermoplastic material. Optionally, a decolorization agent solution is preheated or heated in the presence of a colored thermoplastic, optionally to any decolorization temperature less than 100 °C. Optionally, a decolorization temperature is between 81 °C and 91°C. It has been discovered that, when using an oxidizing agent or free radical generator as a decolorization agent, heating the decolorization agent solution to 88°C to 95°C produces significantly greater decolorization. It was believed, particularly with respect to use with PET that the decolorization temperature should not exceed 82°C so as to maintain the crystalline nature of the material and reduce hazing due to UV irradiation. Thus, it was surprising that this slight increase in temperature produces significantly better results in removing all visible color from the thermoplastic material.

[0054 J A process for forming a decolorized thermoplastic material optionally includes mixing a colored thermoplastic material with a decolorization agent solution for a decolorization time, Mixing is optionally immersing a colored thermoplastic material in a decolorization agent solution, spraying a decolorization agent solution on a colored thermoplastic, or other mixing recognized by one of skill in the art, A decolorization time is optionally any time from 1 minute to 120 minutes, or more. In particular embodiments, a decolorization time is optionally from 1 minute to 30 minutes, optionally from 1 minute to 20 minutes, optionally from 1 minute to 10 minutes, optionally from 5 minutes to 10 minutes. A decolorization time is optionally 1 , 2, 3, 4, 5, 6, 7, 8, 9, 10, 15, 20, 25, or 30 minutes. It was expected that a decolorization time required to produce a fully decolorized material would be 120 minutes or greater. It was, in contrast, surprisingly discovered that full decolorization could be achieved in less than 20 minutes, particularly less tha 10 minutes.

[0055] it is appreciated that full decolorization as used herein is decolorization sufficient to be used in subsequent applications of the thermoplastic material that require clear thermoplastics, in some embodiments, full decolorization results in a thermoplastic materia! with a Yellowness Index (YI) of 0.5 to 2.5, or any value or range therebetween.

[0056] A process of for forming a decolorized thermoplastic material optionally includes irradiating the thermoplastic material subsequent to or simultaneous with the step of mixing. Irradiating is optionally used to produce a radical from a decolorization agent, to directly interact with a dye, or both. Irradiating is optionally exposing a colored thermoplastic material to light with a wavelength from 200 to 400 nm. Optionally, a wavelength is from 250 to 350 nm, optionally from 310 to 320 nm. Irradiating is optionally exposing a colored thermoplastic material to light with a wavelength of 312 nanometers, optionally plus or minus 5 nm or 10 nm. Irradiating is optionally exposing a colored thermoplastic material to light with a wavelength of 254 nanometers, optionally plus or minus 5 nm or 10 nm. A source for UV light is optionally a UV lamp such as that obtainable from Dymax, Corp., Torrington, CT. A thermoplastic is optionally irradiated for an irradiation time. An irradiation time is optionally 1 minute to 30 minutes, or any value or range therebetween, An irradiation time is optionally 1 minute to 20 minutes, optionally 3 minutes to 10 minutes, optionally 5 minute to 7 minutes. An irradiation time is optionally 1 , 2, 3, 4, 5, 6, 7, 8, 9, or 10 minutes. An irradiation time is optionally 5 minutes. An irradiation time is optionally 7 minutes. [0057] Following a decolorization time, or optionally during a decolorization time, a decolorization agent solution is optionally itself subjected to a recycling process to remove dye materials from the solution. The purification of the decolorization agent solution is optionally achieved by passing the used decolorization agent solution through activated carbon, mechanical filtering, skimming, irradiation, or combinations thereof. The activated carbon may be in the form of a column, a bed, or any other configuration that will allow the passage of the used decolorization agent solution resulting in a dye-free decolorization agent solution suitable for reuse. The removal of dye from the decolorization agent solution serves to rene the solution allowing the same solution to remove additional dye from the thermoplastic material.

[0058] it has been found that the provided processes for forming a decolorized thermoplastic are far superior to other processes described in the art. It is common that color changes can be achieved by prior processes, but none of these processes are capable of removing a remaining yellow or brown color to the decolorized materials. The inventive processes provide a decolorized thermoplastic that is fully decolorized and suitable for use in subsequent material production requiring clear thermoplastic materials. In achieving decolorization of a thermoplastic material having a dye impar ing color to the thermoplastic, various combinations of the aforementioned processes or decolorization agents or decolorization agent solutions may be combined simultaneously or sequentially to decolorize the thermoplastic material. Illustrative examples include the combination of a decolorization agents that include: Formula ] and irradiation; Formula I and an oxidizer; and oxidizer and irradiation; Formula I and Formula III, Formula ]] and an oxidizer or reducer; Formula III and an oxidizer; or other combinations as readily envisioned by one of ordinary skill in the art,

[0059] The decolorized thermoplastic made according to the invention may be used in making containers or bottles, in which the total recycled material content in such bottles may be quite low (less than or equal to 20%), relatively high (greater than 20%), or entirely containing recycled material, depending upon the application. Thus, some embodiments involve the manufacture of an article using at least some content that is recycled thermoplastic that has been substantially decolorized by one or more processes provided. Illustrative examples of an article include bottles, computer face-plates, keyboards, bezels and cellular phones, color coded packaging and containers of all types, including ones for industrial components, residential and commercial lighting fixtures, components in building and in construction, tableware, including plates, cups and eating utensils, small appliances and their components, optical and sun-wear lenses, as well as decorative films including such films that are intended for use in film insert molding. In particular embodiments, and article is a bottle made of at least a portion or entirely of recycled PET, Methods of forming bottles are well known in the art,

[0060 J Various aspects of the present in vention are illustrated by the following non-limiting examples. The examples are for illustrative purposes and are not a limitation on any practice of the present invention. It will be understood that variations and modifications can be made without departing from the spirit and scope of the invention. Reagents illustrated herein are commonly commercially available, and a person of ordinary skill in the art readily understands where such reagents may be obtained.

EXAMPLES

Example 1: Decoloration using an oxidizing decolorization agent and environmental mediators.

[0061] Six pounds of color infused PET is flaked as per standard recycling procedure and divided into 75 gram samples. A set of aqueous decolorizing agent solutions are made containing water having from 1% to 20% commercial sodium hypochlorite (CLQROX), Each decolorizing agent solution is heated to a temperature between 81 °C and 91°C. One 75 gram sample of PET flake is added to each decolorizing agent solution under stirring and exposed to UV light of wavelength between 200 and 400 nm for 7 minutes. The flake is then removed, filtered, and rinsed twice in water to remove residual decolorizing agent solution, and then allowed to dry at ambient temperature overnight. Results are illustrated in FIG. 1 .

[0062] While each of the different temperatures clarify the PET, the best results are reached when the decolorizing agent solution is at or in excess of 87°C and better above 88°C and below 95°C. No appreciable yellow hue common to prior procedures is observed.

[0063J The experiments are repeated using several other thermoplastics including polycarbonate, poiyamide, and polyethylene with similar results to that achieved with PET.

Example 2: Direct decoloration.

[0064] Samples of PET and PC (75 grams each) flaked as per standard recycling procedure and previously infused with Disperse Red 1 (1,3-Benzenedicarbonitrile, 2~[2-[4-(diethyiamino)- 2-methylphenyl]diazenyl]-5-methyl-), Disperse Yellow 82 (CAS No: 12239-58-6), Solvent Red 447 (2-[ethyi[4~[2-(4-nitrophenyl)dia.zenyi]phenyi]amino-ethanoi), or Solvent Blue 35 (1 ,4- Bis[butylamino]-9,10-anthraquinone) are divided among several decolorizing agent solutions containing: 1) water (70% w/w), decolorizing agent (2-butoxyethanol) (20% w w) and emulsifier (di ethylene glycol) (10% w/w); 2} water (90% w/w) and decolorizing agent diethyl phthalate (DEP; 5% w/w): 3) Aura solvent and DEP (5% w/w); and 4) decolorizing agent ethyl acetate (100%). Each decolorizing agent solution is preheated to a temperature of 90°C. The thermoplastics are immersed in decolorizing agent solution for a period of 1-5 minutes. The samples are removed, rinsed in water, and dried o vernight at ambient temperature.

[0065] The decolored samples are subjected to UV/Vis spectroscopy and the change of color recorded. FIG. 2 illustrates a UV/Vis spectra of dyed polycarbonate before and after treatment demonstrating that the thermoplastic after treatment is substantially similar to untreated PC. FIG. 3 illustrates PET dyed with Disperse Red 1 before and after treatment using the decolorizing agent 2-b toxyethanol demonstrating that the processes also return PET to a spectra with much greater transmission indicating additional clarity. PET previously colored by Disperse Red 1 is subjected to decolorization in a decolorization solvent that includes an acetate ester also show good color removal. PET decolored in Aura solvent combined with 5% DEP for each time period show nearly full removal of color in the visible spectrum as illustrated in FIG. 4A. Samples of PET previously colored using Disperse Red 1 either bleach treated or treated in a 100% solution of ethyl acetate also demonstrate good decolorization results as illustrated in FIG. 4B.

[0066] Table 1 illustrates the change in color by both the Lab color space (Lab) measurement scale and the XYZ scale calculated from the Lab color measurements for PC flake before or after decolorization using a 2-butoxyethanol decolorization agent.

Table 1:

L A B Haze δ E

Flake molded into plaques:

100 % Control 88.85 -1 .00 3.77 7.01

100 % Dyed Untreated 80.29 16.88 24.53 5.99 7.78

100 % Dyed Treated 84.62 3.59 17.76 7,78 5.39

100 % Dyed Treated (Dark

pieces removed) 86.05 1 .39 13.38 8.94 4.33

75% Control / 25 % Treated 87.80 0.69 6.94 7.12 2.83

50% Control / 50 % Treated 87.02 1 .44 10.02 7.03 3.78

Flake color data:

100% Control flake 68.48 -0.45 -0.41

100% Standard treated flake } 68.15 10.51 3.15 5.33

100% Best Case flake 75.30 -0.12 4.01 4.81 Flake molded into plaques:

100 % Control 69.15 73.43 73.95 6.75

100 % Dyed Untreated 60.79 56.68 36.96 64.58 57.82

100 % Dyed Treated 64.48 66.01 51 .18 37.97 31 .21

100 % Dyed Treated (Dark

pieces removed) 65.06 67.99 58.80 25.09 18.33

75% Control / 25 % Treated 68.95 72.07 69.64 13.41 6.65

50% Control / 50 % Treated 66.99 70.01 64.06 19.30 12.55

Flake color data:

100% Control flake 35.79 37.97 42.20 -5.12

100% Standard treated flake 37.30 37.97 33.36 26.81 31 .93

100% Best Case flake 45.89 48.28 48.65 7.81 12.93

These data demonstrate significant change in yellowness index representative of highly clarified thermoplastic material suitable for use in subsequent non-colored applications,

Example 3: Removal of Disperse Red 1, Disperse Orange 47, or Disperse Yellow 82 from PET films.

[0068] A set of aqueous decolorizing agent solutions are prepared containing either 10% (wt/wf) or 20°/» (wt/wt) commercial sodium hypochlorite (CLORQX) in water. Each decolorizing agent solution is heated to a temperature between 81°C and 91°C. One 75 gram sample of previously dyed amorphous PET film is immersed into each decolorizing agent solution under stirring and exposed to UV light of wavelength between 200 and 400 nm for 7 minutes. Films dyed with either Disperse Red 1 (SCARLET CSB), Disperse Orange 47 (ORANGE MR), or Disperse Yellow 82 (FLUORESCENT 10 GN) are tested. The films are then removed and rinsed twice in water to remove residual decolorizing agent solution, and then allowed to dry at ambient temperature overnight. Each film is subjected to UV/Vis spectroscopy with results illustrated in FIG. 6. FIG. 6A illustrates decolorization of scarlet red CSB colored PET demonstrating significant improvements in transmission. FIG. 6B illustrates decolorization of Orange MR colored PET illustrating excellent transmission increases using 10% sodium hypochlorite decolorization agent, and nearly complete color removal using 20% sodium hypochlorite decolorization agent. FIG. 6C illustrates decolorization of Fluorescent Yellow colored PET demonstrating excellent decolorization of the PET film.

Example 4: Removal of solvent blue 35 and solvent red 447 from PET bottles.

[0069] Cold preform bottles of PET are infused with solvent blue 35 or solvent red 447. For infusion, a colorization solvent including water (70% w w), decolorizing agent (2-butoxyethanol) (20% w/w) and emulsifier (diethylene glycol) (10% w/w) containing either 3 grams of solvent blue 35 or 4 grams of solvent red 447 is heated to a temperature of 96°C. Two sets of PET bottles are placed in individual batches of colorization solvent: 1) PET bottles formed then cooled to room temperature; and 2) PET bottles at 77°C. Bottles are submersed in the colorization solvent for 1, 5, 8, 10, 20, or 30 seconds. The colored bottles are then allowed to cool and dry,

[0070] Colored bottles are cut into single wall sections for subsequent decolorization analyses, A cut section approximately 1 cm x 1 cm square of each of the test bottles is placed in a decolorization solution essentially as described in U.S. Patent No: 6,733,543 that is preheated to a decolorization temperature of 95°C for a decolorization time of 2 minutes. Following decolorization time, the test samples are rinsed twice in water to remove residual decolorizing agent solution and then allowed to dry at ambient temperature overnight. Samples are analyzed by LTV/Vis spectroscopy to determine the level clarity recovered. FIG. 6A illustrates the transmittance spectrum prior to decolorization of an exemplary set of bottles colored with solvent blue 35 for 0 (control), 5, 10, and 20 seconds. FIG. 6B illustrates the transmittance spectrum of an exemplar}' set of bottles colored with solvent red 447 for 0 (control ), 5, 10, and 20 seconds prior to decolorization. Following color removal for two minutes each bottle shows increased transmittance indicating that 77.2% and 74.7% of the dye is remo ved from the bottles dyed with solvent blue 35 for 10 and 20 seconds respectively. In addition, 67% of the solvent red 447 is removed from bottles dyed for 20 seconds. Other bottles dyed for various times show similar increases in transmittance indicating excellent color removal.

[0071] Various modifications of the present invention, in addition to those shown and described herein, will be apparent to those skilled in the art of the above description. Such modifications are also intended to fall within the scope of the appended claims.

[0072] It is appreciated that all reagents are obtainable by sources known in the art unless otherwise specified.

[0073] Patents and publications mentioned in the specification are indicative of the levels of those skilled in the art to which the invention pertains. These patents and publications are incorporated herein by reference to the same extent as if each individual application or publication was specifically and individually incorporated herein by reference.

[0074 J The foregoing description is illustrative of particular embodiments of the in vention, but is not meant to be a limitation upon the practice thereof. The following claims, including all equi valents thereof, are intended to define the scope of the invention.

f0075] We claim:

Claims

1. A process of forming a decolorized thermoplastic material comprising:

providing a thermoplastic material in solid form comprising one or more dyes infused into said material, said dye imparting color to said thermoplastic material;

mixing, immersing, or coating said thennoplastic material with a decolorizing agent solution for a decolorization time of 10 minutes or less and at a decolorization temperature below the melting temperature of said thermoplastic, said solution comprising one or more decolorizing agents; and

decolorizing said thermoplastic material by said mixing, immersing, or coating step thereby forming a decolorized thermoplastic material.

2. The process of claim 1 wherein said decolorization temperature is from 60 degrees Celsius to 98 degrees Celsius. 3. The process of claim 1 wherein said decolorization agent has a structure of

Formula I:

wherein R² and R¹ are each independently H or a Ci-ig alkyl, benzyl, benzoyl, or phenyl; n is 1, 2 or 3; a d m is any value from 1 to 35.

4. The process of claim 3 wherein said decolorization agent includes an R¹ that is an ethyl, propyl or butyl.

5. The process of claim 3 wherein m is 2, 3 or 4.

6. The process of claim 3 wherein n is 2 or 3.

7. The process of claim 3 wherein said benzyl, benzoyl, or phenyl is substituted in the aromatic ring by alkyl and/or halogen.

8. The process of claim 3 wherein said R^f is a C-4 alkyl.

9. The process of any one of claims 1 -6 wherein said decolorization agent butoxyethanol.

10. The process of any one of claims 1-8 wherein said decoiorization agent is in an aqueous solution.

1 1. The process of any one of claims 1 -8 wherein said thermoplastic is polyethylene terephthalate.

12. The process of any one of claims 1-8 wherein said decoiorization temperature is from 81 to 91 degrees Celsius.

13. A process of forming a decolorized thermoplastic material comprising:

providing a thermoplastic material in solid form comprising one or more dyes infused into said material, said dye imparting color to said thermoplastic material;

mixing said thermoplastic material with a decolorizing agent solution for a decoiorization time and at a decoiorization temperature below the melting temperature of said thermoplastic, said solution comprising one or more decolorizing agents, said decolorizing agents selected from the group comprising an oxidizing agent, a reducing agent, or combinations thereof; and

decolorizing said thermoplastic material by said mixing step thereby forming a decolorized thermoplastic material.

14. The process of claim 13 wherein said decolorizing agent is a hypohalite compound.

15. The process of claim 14 wherein said hypohalite is sodium hypochlorite.

16. The process of any one of claims 13-15 further comprising irradiating said thermoplastic material with light having a wavelength in the ultraviolet spectrum or lower,

17. The process of claim 13 wherein said decoiorization agent is of Formula II:

R³— O— O— R⁴ (II)

where R³ and R⁴ are each independent of the other a hydrogen, alkyl, aryl, heteroaryl, acyi, silicon-containing group, lithium, germanium-containing group, phosphorus-containing group, titanium-containing group, organometaliic compound, carbonate, carbamate, or a repeating unit of a polymeric structure.

18. The process of claim 13 wherein said decolorization agent is an organic peroxide or an inorganic peroxide alone or combined with a catalyst. 19. The process of claim 13 wherein said decolorizing agent is hydrogen peroxide.

20. The process of claim 13 wherein said decolorizing agent is a reducing agent selected from the group consisting of zero valent iron, a bisulfite, sodium borohydride, lithium borohydride, potassium borohydride, thiourea dioxide, polymethylhydrosiloxane, and hydrazine.

21. The process of any one of claims 13-15 or 17-20 wherein said decolorization temperature is from 60 degrees Celsius to 98 degrees Celsius.

22. The process of claim 21 wherein said decolorization temperature is from 81 to 91 degrees Celsius.

23. The process of any one of claims 13-15 or 17-20 wherein said decolorization time is 10 minutes or less. 24. The process of claim 23 wherein said decolorization time is from 1-5 minutes.

25, The process of any one of claims 13-15 or 17-12 wherein said thermoplastic is polyethylene terephthalate. 26. The process of any one of claims 13-15 or 17-12 wherein said thermoplastic is polycarbonate.

27. A process for forming a decolorized thermoplastic material comprising:

providing a thermoplastic material in solid form comprising one or more dyes infused into said material, said dye imparting color to said material;

mixing said thermoplastic material with a decolorizing agent solution for a decolorization time and at a decolorization temperature below the melting temperature of said thermoplastic, said solution comprising one or more decolorizing agents, said decolorization agent comprising a structure of Formula III: R⁵-[CO-0-R⁶]_x ( HI)

where ⁵ and R⁶ are each independently: a H, substituted or imsubstituted linear, branched, cyclic, or combination CM S alkyl, CMS alkenyl, Ci-is alkynyl, or phenyl; and where x is any number from 1-4; and

decolorizing said thermoplastic materia] by said mixing step thereby forming a decolorized thermoplastic material,

28. The process of claim 27 wherein said decolorization agent is a plasticizer.

29. The process of claim 28 wherein said plasticizer is selected from the group consisting of bis(2-ethyihexyl) plithalate, butyl benzyl plithalate, diisodecyl plithalate, di-ii-octyl plithalate, diisooctyl plithalate, diisobutyl plithalate, and di-n-hexyl plithalate.

30. The process of claim 27 wherein said decolorization agent is an acetate ester,

31. The process of claim 27 wherein said decolorization agent solution further comprises a second decolorization agent has a structure of Formula I:

R¹— [(0(CH₂)m)n— ]OR² (I)

wherein R² and R¹ are each independently H or a O-jg alkyl, benzyl, benzoyl, or phenyl; n is 1, 2 or 3; and m is any value from 1 to 35.

32, The process of claim 31 wherein said second decolorization agent includes an R^l that is an ethyl, propyl or butyl.

33, The process of claim 31 wherein m is 2, 3 or 4.

34, The process of claim 31 wherein n is 2 or 3.

35, The process of claim 31 wherein said benzyl, benzoyl, or phenyl is substituted in the aromatic ring by alkyl arid/or halogen,

36, The process of claim 31 wherein said second decolorization agent is 2- butoxyethanol.

37. The process of any one of claims 27-36 wherein said decolorization temperature is from 60 degrees Celsius to 98 degrees Celsius.

38, The process of any one of claims 27-36 wherein said decolorization temperature is between 81 and 91 degrees Celsius.

39. The process of any one of claims 27-36 wherein said decolorization time is 10 minutes or less. 40. The process of any one of claims 27-36 wherein said decolorization time is from

1-5 minutes.

41 , The process of any one of claims 27-36 wherein said thermoplastic is polyethylene terephthalate or polycarbonate.

42. A process for forming a decolorized polyethylene terephthalate comprising: mixing polyethylene terephthalate thermoplastic material in solid form with a decolorizing agent solution, said polyethylene terephthalate material comprising one or more dyes infused into said material imparting color prior to said step of mixing; and

decolorizing said polyethylene terephthalate material by said mixing said polyethylene terephthalate with a decolorizing agent solution for a decolorization time and at a decolorization temperature below the melting temperature of said thermoplastic, said solution comprising one or more decolorizing agents thereby forming a decolorized polyethylene terephthalate material. 43. The process of claim 42 wherein said dye in said polyethylene terephthalate material penetrates said material to less than 1 millimeter.

44. The process of claim 42 wherein said dye is a thermoliable dye. 45. The process of claim 42 wherein said dye is an unstable dye.

46. The process of claim 42 wherein said dye is an azo or quinone dye.

47. The process of claim 42 wherein said dye is disperse red 1.

48. The process of claim 42 wherein said decolorization agent solution comprises a decolorization agent having the structure of Formula I:

R^s---[(0(CH2)_m)n--]OR² (I)

where: R¹ and R are each independently 1-1 or a C\-i & alkyl radical, benzyl radical, benzoyl radical, or phenyl radical; n is 2, 3 or 4; and m is any value from 1 to 35;

said decolorization agent substantially free of a dye prior to said step of mixing.

49. The process of claim 48 wherein said decolorization agent includes an R¹ that is an ethyl, propyl, or butyl radical.

50. The process of claim 48 wherein m is 2, 3 or 4. 1. The process of claim 48 wherein n is 2 or 3.

52. The process of claim 48 wherein said benzyl, benzoyl, or said phenyl is substituted in the aromatic ring by alky! and/or halogen.

53. The process of claim 48 wherein said decolorization agent is 2-butoxyethanol.

54. The process of any of claims 42-53 wherein said decolorization agent is in an aqueous solution.

55. The process of any of claims 42-53 further comprising heating said polyethylene terephthalate ma terial to said decolorization temperature for said decolorization time subsequent to or simultaneous with said step of mixing.

56. The process of claim 55 wherein said decolorization temperature is less than 100 degrees Celsius.

57. The process of claim 55 wherein said decolorization temperature is from 81 to 91