Decolorizing composition, decolorization method, and decolorization device

Abstract

A medium comprising a fabric dyed with a dye is decolorized without requiring an absorbent such as cloth.　This decolorizing composition is used for decolorizing a fibrous medium dyed with a dyeing material including a dye having sublimation properties. The decolorizing composition contains at least one of an ether bond or an ester bond in a molecular structure, and contains, as an active ingredient, a compound having a boiling point higher than the fiber opening temperature at which molecular chains of the fiber or the intermolecular forces of the fiber are relaxed.

Description

Composition for decolorization, decolorization method, and decolorization apparatus 【0001】 The present invention relates to a composition for decolorization, a decolorization method, and a decolorization apparatus. 【0002】 As media printed or dyed using sublimation dyes, there are roll screens and streamers used as advertising and promotional tools. Many of this type of media are created, for example, by overlapping a transfer paper for sublimation transfer on which information such as a desired pattern is printed on a polyester fabric, and then transferring the information such as the pattern from the transfer paper to the fabric by applying pressure while heating. 【0003】 In recent years, there has been consideration of decolorizing media printed with information and recycling them. Patent Document 1 discloses a decolorization processing agent (composition for decolorization) used for decolorizing media dyed with sublimation dyes. 【0004】 Japanese Patent Application Laid-Open No. 2007-224128 【0005】 There is a need to decolorize media dyed using a dyeing material containing a sublimable dye. 【0006】 The inventor of the present case diligently studied a method for removing a sublimable dye from a fibrous medium dyed using a dyeing material containing a sublimable dye such as a sublimation dye or a disperse dye having sublimability, thereby decolorizing the medium. As a result, it was found that a fibrous medium dyed using a dyeing material containing a sublimable dye can be decolorized without the need for an absorber such as cloth by using a composition for decolorization having a specific molecular structure. By immersing a fibrous medium dyed using a dyeing material containing a sublimable dye in this composition for decolorization and heating it, the sublimable dye migrates to the composition for decolorization, and the medium is decolorized. That is, it was found that when decolorizing the medium, the medium can be decolorized without the need for an additional absorber for absorbing the dye in addition to the composition for decolorization. 【0007】One aspect of this invention is (1) a decolorizing composition used for decolorizing a fibrous media dyed with a dyeing material containing a sublimable dye, wherein the decolorizing composition contains at least one of an ether bond and an ester bond in its molecular structure and contains as an active ingredient a compound with a boiling point higher than the fiber opening temperature at which the attractive forces between the molecular chains or intermolecules of the fiber loosen. 【0008】 In textile media dyed with dyeing materials containing sublimable dyes, the dye is retained in the gaps between the molecular chains of the fibers that make up the media. The fiber opening temperature refers to the temperature at which the molecular chains of the fibers that make up the media loosen (the gaps widen) to the extent that the dye retained between the molecular chains of the fibers escapes. Decolorizing compositions that contain at least one of ether bonds and ester bonds in their molecular structure have a high affinity for the molecules of sublimable dyes mainly used in sublimation printing. When the decolorizing composition in which the media is immersed is heated to at least the fiber opening temperature, the dye retained in the gaps between the molecular chains of the fibers is transferred from the media to the decolorizing composition, thereby decolorizing the media. 【0009】 One aspect of this case is (2) in (1) above, the compound is a linear compound having the ester bond and the ether bond, and the linear compound is a decolorizing composition having at least one ether bond on one side as seen from the ester bond. 【0010】 Dyeing with sublimation dyes occurs not through chemical bonds such as ionic or covalent bonds, or hydrogen bonds, between the dye and the fabric fibers, but through the interaction or attraction between the structural components of the fiber molecules and the dye molecules. In decolorizing fabric fibers dyed with sublimation dyes, it was thought that applying heat to the fibers would widen the gaps between the molecular chains, causing the trapped dye molecules to move naturally into the decolorizing composition. However, decolorization performance varies depending on the solvent, with some color remaining even in the solvent. Therefore, it is speculated that if the affinity between the dye and the solvent is greater than the affinity between the fabric fibers and the dye, the dye molecules trapped between the fiber molecules may move towards the solvent, thus enabling decolorization. 【0011】One aspect of this case is (3) in (1) above, the compound is a linear compound having a plurality of ether bonds, and the linear compound is an alcohol-based compound having a hydroxyl group at one end, and is a decolorizing composition. 【0012】 When a decolorizing composition containing such a compound is used, and the decolorizing composition in which the media is immersed is heated to at least the fiber-opening temperature, the dye held in the gaps between the molecular chains of the fibers is transferred from the media to the decolorizing composition, thereby decolorizing the media. 【0013】 One aspect of this invention is (4) a decolorizing composition used for decolorizing media printed or dyed with sublimable dyes such as sublimation dyes or sublimable disperse dyes, the decolorizing composition containing at least one compound selected from ethyl acetate dioxazole, 2-(2-ethoxyethoxy)ethanol, dimethyl succinate, dimethyl glutarate, dimethyl adipate, benzyl benzoate, and ethylene carbonate as an active ingredient. 【0014】 When media is immersed in a decolorizing composition containing the above-mentioned compound as an active ingredient and heated to at least the fiber-opening temperature, the dye held in the gaps between the molecular chains of the fibers is transferred from the media to the decolorizing composition, thereby decolorizing the media. 【0015】 One aspect of the present invention is a method for decolorizing a fibrous media dyed with a dyeing material containing a sublimable dye, wherein the decolorizing composition used for decolorizing the fibrous media contains at least one of an ether bond and an ester bond in its molecular structure and contains as an active ingredient a compound with a boiling point higher than the fiber opening temperature at which the molecular chains or intermolecular forces of the fibers loosen, and the decolorizing method involves immersing the fibrous media in the decolorizing composition and heating it at a temperature higher than the fiber opening temperature, or immersing the fibrous media in the decolorizing composition heated at a temperature higher than the fiber opening temperature. 【0016】By heating the decolorizing composition in which the media is immersed to at least the fiber-opening temperature, or by immersing the media in a decolorizing composition heated to a temperature higher than the fiber-opening temperature, the dye held in the gaps between the molecular chains of the fibers can be transferred from the media to the decolorizing composition, thereby decolorizing the media. 【0017】 One aspect of the present invention is (6) an apparatus for decolorizing a fibrous media dyed with a dyeing material containing a sublimable dye, comprising: a decolorizing composition used for decolorizing the fibrous media; a container for containing the fibrous media; and a heating means for heating the decolorizing composition to a temperature higher than the fiber opening temperature at which the molecular chains or intermolecular forces of the fibers are relaxed. 【0018】 By heating a fibrous media and a decolorizing composition in a container, the dye held in the gaps between the molecular chains of the fibers can be transferred from the media to the decolorizing composition, thereby decolorizing the media. 【0019】 According to the present invention, a fabric medium dyed with a dyeing material containing a sublimation dye can be decolorized without the need for an absorbent material such as cloth. 【0020】 This is a table explaining the relationship between heating temperature and heating time when decolorizing using a decolorizing composition. This is a table explaining the relationship between heating temperature and heating time when decolorizing using a decolorizing composition. This is a table explaining the relationship between heating temperature and heating time when decolorizing using a decolorizing composition. This is a table explaining the relationship between heating temperature and heating time when decolorizing using a decolorizing composition. This is a table explaining the relationship between heating temperature and heating time when decolorizing using a decolorizing composition. This is a table explaining the relationship between heating temperature and heating time when decolorizing using a decolorizing composition. This is a table summarizing the evaluation results when decolorizing and drying media using a decolorizing composition. This is a schematic diagram explaining the equipment configuration of the decolorizing apparatus. 【0021】The following describes a decolorizing composition used when decolorizing media dyed with a dyeing material containing a sublimation dye, a method for decolorizing the media using this decolorizing composition, and a method for drying the media after decolorization. 【0022】 [Dyeing Materials] In this specification, "dyeing materials" means dyeing materials that contain sublimation dyes, such as sublimation dyes or sublimable disperse dyes. Sublimation dyes mean conventionally known dyes that have sublimation properties. Sublimable disperse dyes mean organic compounds that are poorly soluble in water and have the property of changing directly from a solid to a gas when heated (sublimation). Furthermore, "sublimable dyes" mean dyes that can dye fibers by vaporizing (sublimating) from a solid dye under predetermined temperature and pressure conditions and depositing onto the fibers, such as sublimation dyes or sublimable disperse dyes. Furthermore, dyeing means expressing colors, patterns, letters, pictures, etc. on fibers using methods such as hand dyeing, screen printing, digital printing, inkjet printing, or transfer printing. 【0023】 [Media M] Media M is not particularly limited as long as it is made of fibers that can be dyed using a dyeing material containing sublimable dyes. Examples of fibers that can be dyed using a dyeing material containing sublimable dyes include fabrics (woven fabrics, knitted fabrics, etc.) made of hydrophobic fibers such as polyester fibers, acetate fibers, and polyamide fibers. Fabrics made by blending, twisting, weaving, or knitting these materials with other types of synthetic fibers or natural fibers are also acceptable. In this embodiment, Media M may particularly include polyester fibers. Furthermore, it is preferable that the polyester fibers are polyester fibers produced by a condensation reaction between a dicarboxylic acid having an aromatic ring and a diol. 【0024】Dyeing using dyeing materials containing sublimable dyes utilizes the principle of dyeing by heat-treating the media M at a predetermined temperature, which creates gaps between the molecular chains of the fibers constituting the media M, and then allowing the sublimated dye molecules to enter and fix into these gaps, thereby dyeing the fibers. The heat treatment during dyeing is performed at a temperature higher than the temperature at which the gaps between the molecular chains of the fibers open, i.e., the fiber opening temperature of 130-140°C, and is considered to be the temperature at which sublimable dyes sublimate (130-220°C) or a temperature lower than the melting point of the fibers, and is therefore performed at 130-220°C. The inventors of this invention have diligently investigated how to decolorize the dyed media M by utilizing the reverse action of this dyeing principle. 【0025】 Examples of media M printed or dyed using dyeing materials containing sublimation dyes include roller screens, pennants, and banners used as advertising and promotional tools. 【0026】 [Decolorizing Composition] The decolorizing composition is a solvent component used when decolorizing media M. The decolorizing composition is a liquid compound having a boiling point higher than the fiber opening temperature of the molecular chains of the fibers constituting media M. In the case of polyester media M, it is a liquid compound having a boiling point higher than the fiber opening temperature of the polyester molecular chains. The inventors of this invention have diligently studied a method for decolorizing media M, a fabric dyed with a dyeing material containing a sublimable dye, particularly polyester media M, by removing the dye. As a result, they found that polyester media M dyed with a sublimable dye can be decolorized without the need for absorbents such as paper or cloth by using a decolorizing composition containing a compound with a specific molecular structure. Specifically, they found that by immersing media M, a fabric dyed with a dyeing material containing a sublimable dye, in the decolorizing composition described below and heating it, the sublimable dye migrates to the decolorizing composition, and the media M is decolorized. In other words, we found that when decolorizing media M, it is possible to decolorize the media without requiring a separate absorbent to absorb the dye in addition to the decolorization composition. 【0027】Furthermore, after decolorization, when the decolorizing composition remaining on media M is removed and media M is heat-dried, a decolorizing composition was found that does not easily cause shrinkage in the dried media M. As a result, it was found that dyed media M can be decolorized without shrinkage and other damage, and then recycled. 【0028】 The decolorizing composition is a solvent component containing at least one compound from among ethyl acetate dioxazole, 2-(2-ethoxyethoxy)ethanol, dimethyl succinate, dimethyl glutarate, dimethyl adipate, benzyl benzoate, and ethylene carbonate as an active ingredient. 【0029】 Ethyl ethyl dioxazole is a linear compound containing ester and ether bonds in its molecular structure. The boiling point of ethyl ethyl dioxazole (218°C) is higher than the fiber-opening temperature at which the molecular chains of polyester loosen. Ethyl ethyl dioxazole has two ether bonds on one side as viewed from the ester bond. 【0030】 2-(2-ethoxyethoxy)ethanol is a linear compound containing an ether linkage in its molecular structure. The boiling point of 2-(2-ethoxyethoxy)ethanol (196°C) is higher than the fiber-opening temperature at which the molecular chains of polyester loosen. 2-(2-ethoxyethoxy)ethanol is an alcohol-based compound with a hydroxyl group at one end. 【0031】 Dimethyl succinate is a linear compound containing ester bonds in its molecular structure. The boiling point of dimethyl succinate (200°C) is higher than the fiber-opening temperature at which the molecular chains of polyester loosen. Dimethyl glutarate is a linear compound containing ester bonds in its molecular structure. The boiling point of dimethyl glutarate (214°C) is higher than the fiber-opening temperature at which the molecular chains of polyester loosen. Dimethyl adipate is a linear compound containing ester bonds in its molecular structure. The boiling point of dimethyl adipate (245°C) is higher than the fiber-opening temperature at which the molecular chains of polyester loosen. 【0032】Benzyl benzoate is a linear compound containing an ester bond in its molecular structure. Benzyl benzoate is a carboxylic acid ester formed by the dehydration condensation of benzoic acid and benzyl alcohol. The boiling point of benzyl benzoate (325°C) is higher than the fiber-opening temperature at which the molecular chains of polyester loosen. Ethylene carbonate is a cyclic compound containing a carbonate bond in its molecular structure. The boiling point of ethylene carbonate (261°C) is higher than the fiber-opening temperature at which the molecular chains of polyester loosen. 【0033】 The decolorizing composition may contain these exemplified compounds (solvent components) individually. The decolorizing composition may contain at least two of these compounds in any proportion. In addition to these compounds, the decolorizing composition may also contain water, other organic solvents, and additives. Note that the mixed solution containing dimethyl succinate, dimethyl glutarate, and dimethyl adipate as main components is NewSolve UC, described later. 【0034】 [Decolorization Test] A decolorization test was conducted using a decolorization composition containing the above-mentioned compounds, with a dyed test media M. (i) Test media M A color chart test pattern was printed onto a polyester fabric (Tropical (product name)) with an area of ​​295 cm² using a printing device (Mimaki Engineering Co., Ltd., JV300 (product name)) with aqueous sublimation ink (Mimaki Engineering Co., Ltd., Sb411 (product name)) on transfer paper (Mimaki Engineering Co., Ltd., TRS95330 (product name)). Then, using a transfer machine (Monti Antonio Co., Ltd.), the test pattern was transferred from the transfer paper to a polyester (Tropical, recycled pongee) media to obtain test media M. (ii) Disperse dyes (water-based sublimation inks) As an example of a dyeing material containing disperse dyes, Maki Engineering Co., Ltd.'s water-based sublimation ink Sb411 (product name) is given, but any disperse dye can be appropriately selected as long as the pigment molecules contained in the disperse dye can be incorporated into the gaps in the molecular chains of the polyester fibers of media M, thereby dyeing or coloring media M. 【0035】(iii) Decolorization Test The decolorization test was performed on test media M through three steps: decolorization, rinsing, and drying, in order to confirm the recyclability of the media after decolorization. 【0036】 The decolorization process was carried out according to the following procedure: (a) The test media M, on which the test pattern was printed, was immersed in the decolorization composition (300 g) in a sample flask (1000 ml). (b) After attaching the sample flask to a rotary vaporizer, the lower part of the sample flask was immersed in a constant temperature bath containing a heat transfer medium heated to a predetermined temperature. At this time, the sample flask was positioned so that the upper edge of the decolorization composition in the sample flask was below the liquid level of the heat transfer medium (oil) in the constant temperature bath. (c) Using the rotary vaporizer, the sample flask was rotated at atmospheric pressure while the sample flask was heated with the heat transfer medium, and the decolorization composition and media M in the sample flask were heated to a first predetermined temperature while being stirred for a first predetermined time. 【0037】 The rinsing process was carried out according to the following procedure: (a) The media M after the decolorization process is immersed in the decolorization composition in another sample flask. The decolorization composition used here is the same decolorization composition used in the decolorization process, but unused. (b) After attaching the sample flask to the rotary vaporizer, the lower part of the sample flask is immersed in a constant temperature bath that stores a heat transfer medium heated to a predetermined temperature. (c) Using the rotary vaporizer, the sample flask is heated with the heat transfer medium while rotating the sample flask at atmospheric pressure, and the decolorization composition and media M in the sample flask are heated while stirring for a second predetermined time. The second predetermined time is shorter than the first predetermined time. The heating temperature at this time is the same as in the decolorization process. The rinsing process may be omitted, but it is preferable to carry it out in principle in order to prevent the media M from being re-stained by dye components that have moved into the decolorization composition during the decolorization process. 【0038】The drying process was carried out according to the following procedure: (a) After the rinsing process, the media M was subjected to high temperature and high pressure using an Itsumi Co., Ltd. AF-54TEN small heat transfer press to remove any remaining decolorizing composition from the media M, and the media M was dried at a first drying temperature. The press pressure was set to approximately 0.04 to 0.05 MPa. 【0039】 [Evaluation Test] The decolorizing composition was evaluated based on the following evaluation items: (I) Decolorization Evaluation Test After the drying process, the printed test pattern was visually checked to see if it remained on the media M. A state with no color remaining was marked as "○", a state with even a slight color remaining was marked as "△", and a state where decolorization was not achieved was marked as "×". Note that "△" also includes cases where the media M is slightly re-stained by the dye transferred to the decolorizing composition. (II) Shrinkage Evaluation Test The ratio of the area R2 of the media M after the drying process to the area T1 of the media before decolorization (area ratio: R2 / R1) was calculated, and a case where the area ratio was 95% or more (less shrinkage) was marked as "○", and a case where it was less than 95% was marked as "×". 【0040】 [Decolorization conditions] Decolorization conditions were investigated using ethyl acetate dioxol and Newsolve UC (main components are dimethyl succinate, dimethyl glutarate, and dimethyl adipate). 【0041】 Figure 1 is a table illustrating the relationship between heating temperature and heating time when decolorization is performed using a decolorizing composition. Figure 1 summarizes the results when ethyl acetate dioxol and Newsolve UC are used as the decolorizing composition. 【0042】As shown in Fig. 1, in the decolorization process, when the decolorization composition in which polyester fibers are immersed is stirred while being heated at a temperature of 140°C to 180°C (the first predetermined temperature), which is higher than the fiber-opening temperature of the polyester fibers, it was confirmed that the dye can be transferred from the medium M to the decolorization composition to decolorize the medium M. In this case, it was confirmed that the higher the heating temperature, the shorter the decolorization time (stirring time: the first predetermined time). From Fig. 1, when decolorizing the medium M using the decolorization composition according to this embodiment, the heating temperature for decolorization is 140°C to 180°C, preferably 150°C to 170°C, and more preferably approximately 160°C. Here, "approximately 160°C" does not mean 160°C in a strict sense. Considering the temperature fluctuation in temperature control, it means that it is sufficient if the heating state is such that it is heated at an average of 160°C throughout the entire decolorization process. 【0043】 The higher the decolorization temperature, the shorter the decolorization time. However, when the temperature is increased, it may affect the surface properties of the medium M. Here, the "surface properties" are, for example, the feel and texture of the medium M. In this embodiment, as the decolorization conditions in the decolorization process in the following description, a heating temperature of 160°C and a decolorization time of 12 minutes were adopted. This is to enable confirmation of differences in the actions and effects of each compound exemplified as the decolorization composition in the decolorization process. 【0044】 Here, although specific description is omitted, in the rinsing process, the medium M that has completed the decolorization completion process is heated at a temperature of 140°C to 180°C (the first predetermined temperature), which is higher than the fiber-opening temperature of the polyester fibers, while performing a rinsing time (the second predetermined time) that is shorter than the decolorization time (the first predetermined time). The heating temperature (the second heating temperature) in the rinsing process may be lower than the heating temperature of 140°C to 180°C (the first predetermined temperature) in the above-described decolorization process as long as it is higher than the fiber-opening temperature of the polyester fibers. 【0045】 [Drying Conditions] Examination was conducted on the drying conditions in the drying process of the medium M decolorized using ethyl acetate di - eucalyptol and New Solv UC (the main components are dimethyl succinate, dimethyl glutarate, and dimethyl adipate). 【0046】 Figures 2 and 3 are tables for explaining the relationship between the heating temperature (the third predetermined temperature) and the heating time (the third predetermined time) when decolorization is performed using the decolorizing composition. In Figure 2, the results are summarized when Newsorb UC is used as the decolorizing composition. In Figure 3, the results are summarized when ethyl acetate diuxol is used as the decolorizing composition. 【0047】 Here, the "weight standard value" in Figures 2 and 3 is a parameter for observing the progress of drying based on weight. The "weight standard value" is calculated by the following formula (1). Weight standard value = (Wnw - Wed) / (Wst - Wed) ··· (1) Wst: Mass of the media before the start of drying Wed: Mass of the media at the end of drying Wnw: Mass of the media at the current point after the start of drying 【0048】 The weight standard value is initially 1.00, and as drying progresses and the amount of the decolorizing composition remaining on the media decreases, the value becomes smaller. When drying is completed, it becomes approximately zero (= 0.00). 【0049】 The "area retention rate" is a parameter for observing the change in the size of the media before and after drying. The "area retention rate" is calculated by the following formula (2). Area retention rate = Rnw / Rst ··· (2) Rnw: Area of the media in the dried state after drying is completed Rst: Area of the media in the dried state before the start of decolorization 【0050】 The area retention rate becomes smaller as the shrinkage of the media M increases. An area retention rate of 100% means a state without shrinkage. 【0051】As is clear from Figure 2, when the decolorizing composition is NewSolve UC, the heating temperature for drying (third predetermined temperature) when drying the media M after decolorization using NewSolve UC is 160°C to 200°C, preferably 170°C to 190°C, and more preferably approximately 180°C. Here, approximately 180°C does not mean 180°C in the strict sense. It means that, taking into account temperature fluctuations in temperature control, it is sufficient if the heating state is such that the average temperature is around 180°C throughout the entire drying process. The higher the drying temperature, the shorter the drying time (third heating time). However, the higher the temperature, the greater the shrinkage of the media M after drying. Therefore, when the decolorizing composition is NewSolve UC, considering the time required for drying and the shrinkage of the media, the heating temperature for drying is preferably 170°C to 190°C, more preferably approximately 180°C, and the drying time is preferably a maximum of about 2 minutes. 【0052】 As is clear from Figure 3, when the decolorizing composition is ethyl acetate dioxazole, the heating temperature for drying (third predetermined temperature) when drying media M after decolorization with ethyl acetate dioxazole is 160°C to 200°C, preferably 170°C to 190°C, and more preferably approximately 180°C. Here, approximately 180°C does not mean 180°C in the strict sense. It means that, taking into account temperature fluctuations in temperature control, it is sufficient if the heating state is such that the average temperature is around 180°C throughout the entire drying process. The higher the drying temperature, the shorter the drying time (third predetermined time). However, the higher the temperature, the greater the shrinkage of media M after drying. Therefore, when the decolorizing composition is NewSolve UC, considering the time required for drying and the shrinkage of the media, the heating temperature for drying is preferably 170°C to 190°C, more preferably approximately 180°C, and the drying time is preferably a maximum of about 2 minutes. 【0053】When using ethyl acetate diyukisol, considering the drying time and media shrinkage, the heating temperature for drying is preferably 170°C to 190°C, more preferably approximately 180°C, and the drying time is preferably a maximum of about 3 minutes. When using ethyl acetate diyukisol, the drying process can be carried out at a lower temperature (milder temperature) than in the case of NewSolve UC. It has been confirmed that this suppresses the shrinkage of media M after drying. 【0054】 In addition to the above-mentioned compounds (NewSolve UC, ethyl acetate diyukisol), other compounds effective for decolorizing dye-stained media include 2-(2-ethoxyethoxy)ethanol, DEDG (diethylene glycol diethyl ether), and 3-methoxy-N,N-dimethylpropanamide. The drying process for these compounds was also evaluated under similar drying conditions. 【0055】 Figures 4 to 6 are tables illustrating the relationship between the heating temperature (third predetermined temperature) and heating time (third predetermined time) when decolorization is performed using a decolorizing composition. Figure 6 summarizes the results when 2-(2-ethoxyethoxy)ethanol is used as the decolorizing composition. It was confirmed that when 2-(2-ethoxyethoxy)ethanol is used at a drying temperature of 200°C, the media shrinks significantly. However, it was confirmed that when drying is performed at a lower drying temperature, preferably below 180°C, the media M can be dried in a short time while suppressing shrinkage. 【0056】 Figure 5 summarizes the results when DEDG (diethylene glycol diethyl ether) is used as the decolorizing composition. While it was confirmed that DEDG (diethylene glycol diethyl ether) caused significant media shrinkage at a drying temperature of 200°C, it was found that drying at a lower temperature, preferably below 180°C, allowed for rapid drying of media M while suppressing shrinkage. 【0057】Figure 6 summarizes the results when 3-methoxy-N,N-dimethylpropanamide was used as the decolorizing composition. As shown in Figure 6, it was confirmed that when the drying temperature was higher than 180°C, media M shrank significantly, but when the drying temperature was 160°C, it was confirmed that media M could be dried in a short time while suppressing shrinkage. 【0058】 Figure 7 summarizes the evaluation results when media is decolorized and dried using the decolorizing composition according to this embodiment. As shown in Examples 1 to 8 in Figure 7, it was confirmed that when ethyl acetate diukazole, 2-(2-ethoxyethoxy)ethanol, dimethyl succinate, dimethyl glutarate, dimethyl adipate, benzyl benzoate, ethylene carbonate, and NewSolve UC are used as the decolorizing composition, dye-dyed media M can be appropriately decolorized and recycled. In Comparative Example 1, 3-methoxy-N,N-dimethylpropanamide was able to decolorize appropriately, but the media shrank significantly before and after recycling, making it unsuitable for recycling by decolorizing the media. Furthermore, in Comparative Examples 2 to 5, diethylene glycol, ethylene glycol, acetone, and oleic acid were able to suppress media shrinkage, but it was confirmed that decolorization could not be performed appropriately. 【0059】 In the above-described embodiment, an example was given in which the decolorization step and the rinsing step are performed by immersing the sample in decolorization composition (300 g) in different sample flasks (1000 ml), a so-called batch method. For example, the process may also be carried out in a continuous manner, in which the media passes sequentially through a first tank containing the decolorization composition used in the decolorization step and a second tank containing the decolorization composition used in the rinsing step. 【0060】Figure 8 is a schematic diagram illustrating the configuration of a decolorization apparatus 1 used when decolorizing media M using a decolorization composition. Figure 8(a) shows the apparatus configuration when decolorization is performed in a batch manner. The decolorization apparatus 1 for batch decolorization includes a container 2 for storing the decolorization composition S, a heating device 3 (heating means) for heating at least one of the decolorization composition S supplied to the container 2 and the container 2, and a pressing device 4 (drying means) for drying the decolorized media M. In the decolorization apparatus 1 shown in Figure 8(a), a container 2 for the decolorization process and a container 2 for the rinsing process are provided. The decolorization composition S is stored in the container 2. 【0061】 Decolorization of the media M, which is the object to be decolorized, is carried out for a predetermined time by placing the media M into a container 2 containing the decolorizing composition S, and controlling the heating device 3 so that the temperature of the media M in contact with the decolorizing composition S is at least the fiber opening temperature. It is preferable to stir the decolorizing composition S and media M in the container 2 during this process. Rinsing of the decolorized media M is carried out by placing the decolorized media M into another container 2 containing the decolorizing composition S and rinsing for a predetermined time. It is preferable to stir the decolorizing composition S and media M in the container 2 during this process. Drying of the rinsed media M is carried out by using a press device 4 to press-heat the rinsed media M at a third predetermined temperature higher than the fiber opening temperature. Alternatively, the decolorizing composition, heated to at least the fiber opening temperature, may be added to the container 2 containing the media M. 【0062】 Figure 8(b) shows the apparatus configuration for continuous decolorization. The decolorization apparatus 1 for continuous decolorization is provided with a container 2' for storing the decolorization composition S and an air drying device 4' (drying means) for drying the decolorized media M along the conveying path of the conveyor V. In the decolorization apparatus 1 shown in Figure 8(b), a container 2' for the decolorization process and a container 2' for the rinsing process are provided. The decolorization composition S is stored in the container 2'. The container 2' is equipped with a heating device 3 (heating means) for heating at least one of the decolorization composition S supplied to the container 2' and the container 2'. 【0063】 The media M, which is the object to be decolorized, is supported by a conveyor V and passes sequentially through a container 2' for the decolorization process, a container 2' for the rinsing process, and an air-drying device 4' for the drying process. Decolorization of the media M occurs when the media M passes through a container 2' containing the decolorization composition S. Rinsing of the decolorized media M occurs when the decolorized media M passes through another container 2' containing the decolorization composition S. Drying of the rinsed media M occurs when the rinsed media M passes through an air-drying device 4'. 【0064】 As described above, the decolorizing composition according to this embodiment has the following configuration: (1) The decolorizing composition is used to decolorize a fibrous media dyed with a dyeing material containing a sublimable dye. The decolorizing composition contains at least one of ether bonds and ester bonds in its molecular structure and contains as an active ingredient a compound with a boiling point higher than the fiber opening temperature at which the attractive forces between the molecular chains or molecules of the fiber loosen. 【0065】 In dyed fiber media, the dyeing material is held in the gaps between the molecular chains of the fibers that make up the media. The fiber-opening temperature refers to the temperature at which the molecular chains of the fibers that make up the media loosen enough (the gaps widen) to allow the dyeing material held between the molecular chains to escape, or the temperature at which the intermolecular attractive forces of the fibers weaken. Decolorizing compositions that contain at least one of ether bonds and ester bonds in their molecular structure have a high affinity for dyeing materials. When the decolorizing composition into which media M is immersed is heated to at least the fiber-opening temperature, the dye held in the gaps between the molecular chains of the fibers is transferred from the media to the decolorizing composition, thereby decolorizing the media. 【0066】 Examples of compounds that satisfy this requirement include ethyl acetate diyukisol, 2-(2-ethoxyethoxy)ethanol, dimethyl succinate, dimethyl glutarate, and dimethyl adipate. By including at least one of these compounds as an active ingredient, the shrinkage of media M can be suppressed while appropriately decolorizing media M. This allows media printed with dyes to be decolorized and recycled. 【0067】 (2) In (1) above, the compound is a linear compound having an ester bond and an ether bond. A linear compound is a compound having at least one ether bond on one side as seen from the ester bond. 【0068】 In dyeing with sublimation dyes, the dye adheres to the fabric fibers not through chemical bonds such as ionic or covalent bonds, or hydrogen bonds formed by intermolecular forces, but through the interaction or attraction between the structural components of the fiber molecules and dye molecules. In decolorizing fabric fibers dyed with sublimation dyes, it was thought that applying heat to the fibers would widen the gaps between the molecular chains, causing the trapped dye molecules to move naturally into the decolorizing composition. However, decolorization performance varies depending on the solvent, with some color remaining even within the solvent. Therefore, if the affinity between the dye and the solvent is greater than the affinity between the fabric fibers and the dye, the dye molecules trapped between the fiber molecules move towards the solvent, resulting in decolorization. 【0069】 Ethyl acetate diyukisol is an example of a compound that satisfies these requirements. By including ethyl acetate diyukisol as an active ingredient, the media M can be appropriately decolorized while suppressing shrinkage. This allows media printed with dyes to be decolorized and recycled. Since there is little shrinkage of the media during decolorization, an improvement in the recycling yield can be expected. 【0070】 (3) In (1) above, the compound is a linear compound having multiple ether bonds. A linear compound is an alcohol-based compound having a hydroxyl group at one end. 【0071】 When the decolorizing composition in which the media is immersed is heated to at least the fiber-opening temperature, the dye held in the gaps between the polyester molecular chains is transferred from the media to the decolorizing composition, thereby decolorizing the media. 【0072】An example of a compound that satisfies this requirement is 2-(2-ethoxyethoxy)ethanol. By including 2-(2-ethoxyethoxy)ethanol as an active ingredient, the shrinkage of media M can be suppressed while appropriately decolorizing media M. This allows media printed with dyes to be decolorized and recycled. 【0073】 (4) The decolorizing composition is used to decolorize media printed or dyed with sublimable dyes such as sublimation dyes or sublimable disperse dyes. The decolorizing composition contains at least one compound from among ethyl acetate dioxazole, 2-(2-ethoxyethoxy)ethanol, dimethyl succinate, dimethyl glutarate, dimethyl adipate, benzyl benzoate, and ethylene carbonate as an active ingredient. 【0074】 By including at least one of these compounds as an active ingredient, the media M can be appropriately decolorized while suppressing shrinkage. This allows media printed with dyes to be decolorized and recycled. Since there is less shrinkage of the media during decolorization, an improvement in the recycling yield can be expected. 【0075】 (I) The fibrous media is a polyester media dyed with a dyeing material containing a sublimable dye. 【0076】 In dyed polyester media, the dye is held in the gaps between the polyester molecular chains that make up the media. At the fiber-opening temperature, the polyester molecular chains that make up the media loosen to the extent that the dye held between the polyester molecular chains escapes (the gaps widen). A decolorizing composition containing at least one of ether bonds and ester bonds in its molecular structure has a high affinity for the molecules of sublimable dyes mainly used in sublimation printing. When the decolorizing composition into which media M is immersed is heated to at least the fiber-opening temperature, the dye held in the gaps between the polyester molecular chains is transferred from the media to the decolorizing composition, thereby decolorizing the media. 【0077】(II) In any one of (1) to (4) or (I) above, the fibrous media is a plain weave fabric or a twill weave fabric. 【0078】 With this configuration, when media M is heated to its opening temperature, the spacing between weaves widens. The decolorizing composition described above has a high affinity for the molecules of sublimable dyes mainly used in sublimation printing, and as the spacing between weaves widens, the opportunities for contact with the sublimable dye molecules incorporated into the interior of media M increase. This allows the dye incorporated between the molecular chains of the fibers inside media M to be transferred to the decolorizing composition, thereby enabling effective decolorization of media M. Furthermore, because media M is a woven fabric, excessive shrinkage of the media after drying due to heating and pressurization can be suppressed. As a result, media that is a plain weave or twill weave fabric can be decolorized and reused appropriately, making it possible to decolorize polyester media printed with dyes and recycle them. 【0079】 The present invention can also be specified as a method for decolorizing a fibrous media. Here, the fibrous media is dyed using a dyeing material containing a sublimation dye, such as a sublimation dye or a sublimable disperse dye. (5) Decolorization of the fibrous media is carried out using a decolorizing composition that contains at least one of ether bonds and ester bonds in its molecular structure, and also contains as an active ingredient a compound with a boiling point higher than the fiber opening temperature at which the molecular chains or intermolecular forces of the fibers loosen. Decolorization of the fibrous media (decolorization step) is carried out by immersing the fibrous media in the decolorizing composition and heating it at a temperature higher than the fiber opening temperature, or by immersing it in the decolorizing composition that has been heated at a temperature higher than the fiber opening temperature. 【0080】 This method allows the dye, which is held in the gaps between the molecular chains of the fibers constituting the media M, to be transferred from the media M to the decolorizing composition, thereby decolorizing the media M. 【0081】(III) The decolorization method comprises a decolorization step of immersing a fiber-based media M in a decolorization composition heated to a first predetermined temperature higher than the fiber opening temperature at which the molecular chains of the fibers constituting the media loosen for a first predetermined time, thereby transferring the dye from the media M to the decolorization composition and decolorizing the media M, and a drying step of pressing and heating the decolorized media M at a third predetermined temperature higher than the fiber opening temperature for a third predetermined time to dry the media M. 【0082】 A decolorizing composition containing a compound that has at least one of ether bonds and ester bonds in its molecular structure has a high affinity for the molecules of sublimable dyes mainly used in sublimation printing. When the decolorizing composition in which media M is immersed is heated to a first predetermined temperature at least higher than the fiber opening temperature, the dye held in the gaps of the molecular chains is transferred from media M to the decolorizing composition, thereby decolorizing media M. 【0083】 Furthermore, the decolorized media M is dried by pressing it at a third predetermined temperature (e.g., 180°C) higher than the fiber opening temperature for a third predetermined time (e.g., 3 minutes). In this case, if a decolorizing composition containing a compound with at least one of ether bonds and ester bonds in its molecular structure is used for decolorizing the media M, it is possible to remove the decolorizing composition remaining on the media M while suppressing shrinkage of the media M during the drying process. In other words, the media M can be appropriately decolorized while suppressing shrinkage of the media M. This makes it possible to decolorize media printed with dyes and recycle them. At this time, the drying conditions are milder than when pressing and drying at 200°C for 1 minute, so deterioration of the surface properties such as the feel and texture of the media M can be suppressed. This makes it possible to provide a decolorizing method for media M that can withstand repeated recycling. 【0084】 (IV) In the above (III), the decolorizing composition contains at least one compound selected from ethyl acetate diyukisol, 2-(2-ethoxyethoxy)ethanol, dimethyl succinate, dimethyl glutarate, dimethyl adipate, benzyl benzoate, and ethylene carbonate as an active ingredient. 【0085】 By including at least one of these compounds as an active ingredient, the shrinkage of media M can be suppressed while appropriately decolorizing media M. This allows media printed with dyes to be decolorized and recycled. Since there is less shrinkage of the media during decolorization, an improvement in the recycling yield can be expected. 【0086】 (V) In the above (IV), further, following the decolorization step, the decolorized media is immersed in unused decolorization composition heated to a first predetermined temperature higher than the fiber opening temperature at which the molecular chains of the fibers loosen, for a second predetermined time shorter than the first predetermined time. 【0087】 This prevents the media M from being re-stained by the dye components that have migrated into the decolorizing composition during the decolorization process. 【0088】 (VI) In (V) above, the decolorization and rinsing of the fibrous media is carried out in a batch manner, in which the fibrous media is agitated together with the decolorization composition in a storage container for storing the decolorization composition, or in a continuous manner, in which the fibrous media passes through a storage tank for storing the decolorization composition. 【0089】 With this configuration, the dye held in the gaps between the molecular chains of the fibers can be transferred from the media to the decolorizing composition, thereby decolorizing the media. 【0090】 The present invention can also be specified as a decolorization apparatus for decolorizing a fibrous media dyed with a dyeing material containing a sublimable dye. (6) The decolorization apparatus 1 includes a decolorization composition S used for decolorizing a fibrous media M, containers 2 and 2' for containing the fibrous media, and a heating device 3 as a heating means for heating the decolorization composition S to a temperature higher than the fiber opening temperature at which the molecular chains of the fibers constituting the media M or the intermolecular attractive forces of the fibers loosen. 【0091】 With this configuration, the dye held in the gaps between the molecular chains of the fibers can be transferred from the media to the decolorizing composition, thereby decolorizing the media. 【0092】Although embodiments of the present invention have been described above, the present invention is not limited to the embodiments shown. It can be modified as appropriate within the scope of the technical idea of ​​the invention. 【0093】 M Media 1 Decolorization device V Conveyor 2, 2' Container 3 Heating device (heating means) 4 Pressing device (drying means) 4' Air drying device (drying means)

Claims

1. A decolorizing composition used for decolorizing a textile media dyed with a dyeing material containing a sublimable dye, comprising as an active ingredient a compound having a boiling point higher than the fiber opening temperature at which the attractive forces between the molecular chains or intermolecules of the fiber are relaxed, wherein the molecular structure contains at least one of an ether bond and an ester bond.

2. The decolorizing composition according to claim 1, wherein the compound is a linear compound having the ester bond and the ether bond, and the linear compound has at least one ether bond on one side as seen from the ester bond.

3. The decolorizing composition according to claim 1, wherein the compound is a linear compound having a plurality of ether bonds, and the linear compound is an alcohol-based compound having a hydroxyl group at one end.

4. A decolorizing composition used for decolorizing textile media dyed with a dyeing material containing a sublimable dye, comprising at least one compound selected from ethyl acetate dioxazole, 2-(2-ethoxyethoxy)ethanol, dimethyl succinate, dimethyl glutarate, dimethyl adipate, benzyl benzoate, and ethylene carbonate as an active ingredient.

5. A method for decolorizing a fibrous media dyed with a dyeing material containing a sublimable dye, wherein the decolorizing composition used for decolorizing the fibrous media contains at least one of an ether bond and an ester bond in its molecular structure and contains as an active ingredient a compound with a boiling point higher than the fiber opening temperature at which the molecular chains or intermolecular forces of the fibers are relaxed, and the decolorizing method comprises immersing the fibrous media in the decolorizing composition and heating it at a temperature higher than the fiber opening temperature, or immersing the fibrous media in the decolorizing composition heated at a temperature higher than the fiber opening temperature.

6. A decolorizing apparatus for decolorizing a fibrous media dyed with a dyeing material containing a sublimable dye, comprising: a decolorizing composition used for decolorizing the fibrous media; a container for containing the fibrous media; and a heating means for heating the decolorizing composition to a temperature higher than the fiber opening temperature at which the molecular chains or intermolecular forces of the fibers are relaxed.

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