METHOD FOR PRODUCING COLORED YARNS AND/OR COLORED FABRICS IN PARTICULAR WITHOUT OR WITH ONLY LIMITED AMOUNT OF WASTEWATER DISCHARGE

Abstract

This invention relates to a method for producing a colored yarn based on synthetic fibers, wherein the method comprises the addition of a spinning additive. The spinning additive is self-elutable and/or self-sluicing upon washing the yarn and/or a fabric spun from the yarn with an aqueous solution and/or the spinning additive is water-soluble. The spinning additive can therefore be easily removed from the yarn and/or fabric produced of the yarn by washing with water.

Claims

1. A method for producing a colored yarn based on synthetic fibers, wherein the method comprises: adding of a spinning additive, wherein the spinning additive is self-elutable and/or self-sluicing upon washing the yarn and/or a fabric spun from the yarn with an aqueous solution and/or the spinning additive is water-soluble.

2. The method according to claim 1, wherein the method for producing a colored yarn includes and/or is a dope-dyeing process.

3. The method according to claim 2, wherein the dope-dyeing process comprises the method steps of providing the base materials as a polymer melt and/or extruding the base materials, and spinning a yarn from the molten polymer.

4. The method claim 1, wherein the method comprises the following method steps in the following order: a) providing separately from another a color masterbatch material and a plastic granular base material, followed by mixing to obtain a mixed color masterbatch material and plastic granular base material, and/or providing a mixed color masterbatch material and plastic granular base material, b) providing the mixed color masterbatch material and plastic granular base materials as molten polymer and/or extruding the mixed color masterbatch material and plastic granular base materials, c) spinning a yarn from the molten polymer, adding a spinning additive in at least one of the method steps a), b) and/or c), wherein the spinning additive is self-elutable and/or self-sluicing upon washing the yarn and/or a fabric spun from the yarn with an aqueous solution.

5. The method according to claim 4, wherein the plastic granular base material comprises and/or is a thermoplastic polymer material.

6. The method according to claim 1, wherein the added spinning additive comprises at least one surface-active substance based on ethyleneoxide, propylenoxide and mixtures thereof and/or wherein the surface-active substance is a substance from the group of polyethers.

7. The method according to claim 1, wherein the added spinning additive in addition comprises surfactants, preservatives, lubricants.

8. The method according to claim 1, wherein the method comprises a further method step: manufacturing a colored fabric from the yarn.

9. The method according to claim 1, wherein the method comprises a further method step: washing and finishing the obtained colored fabric.

10. A method for producing a colored fabric based on synthetic fibers, wherein the method comprises the addition of a spinning additive, wherein the spinning additive is self-elutable and/or self-sluicing upon washing the fabric with an aqueous solution and/or wherein the spinning additive is water-soluble, and/or wherein the method includes a method for producing a colored yarn based on synthetic fibers according to claim 1.

11. The method for producing a colored fabric based on synthetic fibers, wherein the method includes a method for producing a colored yarn based on synthetic fibers according to claim 1, wherein the aqueous solution used while washing and finishing the obtained colored fabric is subjected to a treatment process.

12. The method according to claim 11, wherein in a first process step i) of the treatment process the aqueous solution used is treated with a water cleaning agent.

13. (canceled)

14. A colored yarn comprising a spinning additive, wherein the spinning additive is self-elutable and/or self-sluicing upon washing the yarn with an aqueous solution.

15. The colored fabric obtained by a method for producing a colored fabric based on synthetic fibers according to claim 1.

16. The method according to claim 12, wherein the water cleaning agent is selected such that remains in the aqueous solution used coagulate; and/or wherein the water cleaning agent is selected from flocculants, flocculation aids, clarifying agents, precipitants, coagulants, pH-regulators, and mixtures thereof.

17. The method according to claim 16, wherein the water cleaning is inorganically based.

18. A method for producing a colored yarn based on synthetic fibers, wherein the method comprises the following method steps in the following order: a) providing separately from another a color masterbatch material and a plastic granular base material, followed by mixing to obtain a mixed color masterbatch material and plastic granular base material, and/or providing a mixed color masterbatch material and plastic granular base material, b) providing the mixed color masterbatch material and plastic granular base materials as molten polymer and/or extruding the mixed color masterbatch material and plastic granular base materials, c) spinning a yarn from the molten polymer, adding a spinning additive in at least one of the method steps a), b) and/or c), wherein the spinning additive is self-elutable and/or self-sluicing upon washing the yarn and/or a fabric spun from the yarn with an aqueous solution.

19. The method according to claim 18, wherein in at least one of the method steps a), b) and/or c) the added spinning additive comprises at least one surface-active substance based on polyethylenoxide, polypropylenoxide and copolymers and mixtures thereof, and/or wherein the surface-active substance is a substance from the group of polyethers, wherein the polyether is a polyether of ethylenoxide, propylenoxide and mixtures thereof, wherein the surface-active substance is selected from the group of glycerol ethoxylate, polyoxyethylene-polyoxypropylene block-copolymers (Poloxamer), potassium polyoxyethylene laurylether phosphate, and mixtures thereof.

20. The method according to claim 18, wherein the method comprises a further method step: manufacturing a colored fabric from the yarn as a method step d).

21. The method according to claim 20, wherein after manufacturing a colored fabric from the yarn and/or method step d), the method comprises a further method step: washing and finishing the obtained colored fabric as a method step e).

Description

BRIEF DESCRIPTION OF THE DRAWINGS

[0114] Additional advantages, features, properties and aspects of the present invention are appar-ent from the claims and the following description and a preferred embodiment with reference to the drawing. The drawing shows:

[0115] FIG. 1 a schematic view of a melt spinning plant;

[0116] FIG. 2 a flow chart of the water treatment process of raw wastewater of a yarn/fabric washing process;

[0117] FIG. 3 an air flotation device of the water treatment process from FIG. 2; and

[0118] FIG. 4 shows an exemplary a fabric based on a yarn produced with the melt spinning plant.

DETAILED DESCRIPTION

[0119] In the figures, some of which are not to scale and are only schematic, the same reference symbols are used for identical, equivalent or similar parts and components, whereby corresponding or comparable properties or advantages are achieved even if they are not re-peated.

[0120] FIG. 1 shows a melt spinning plant/system 1 for producing a colored yarn 2 based on synthetic fibers 3, whereby the fibers 3 and/or yarns 2 are colored using the so-called dope-dyeing process.

[0121] Various synthetic yarns 2, for example made of polyester, polyethylene, polyethylene terephthalate and/or polyamide, can be produced by using the melt spinning process.

[0122] A base material is required to produce the yarn 2. The base material comprises and/or is preferably a plastic and/or polymer base material. The plastic base material can be provided as a plastic granular base material. It is also possible to use a plastic powder base material. Here and preferable, the base material comprises a plastic granular base material.

[0123] A color masterbatch material can be mixed with the plastic granular base material in order to obtain the desired color of the fiber 3. The color masterbatch material contains at least one colorant for coloring the plastic or the fiber 3.

[0124] The colorant may comprise color pigments and/or chemicals. The colorant is usually incorporated in a highly concentrated form in a carrier material or resin that is compatible with the plastic used as plastic base material. It is particularly preferred that the colorant is mixed with raw polymer, i.e. untreated polymer or polymer granulate, to produce the color masterbatch. Preferably, the colorant is mixed with the same polymer that is used for yarn 2 production and/or as plastic base material. For example, in the production of a polyethylene terephthalate yarn 2, the colorant is preferably incorporated into polyethylene terephthalate. The color masterbatch material can then comprise colorants and polyethylene terephthalate.

[0125] In addition, the color masterbatch material can comprise at least one dispersing agent and/or a solvent. For example, a resin can be used as a solvent.

[0126] The color masterbatch material and the plastic granular base material can be mixed to obtain a mixed color masterbatch material and plastic granular base material, as method step a). The base material then comprises the color masterbatch material and the plastic granular base material.

[0127] The color masterbatch material can be provided and/or mixed with the plastic granular base material in an amount in the range of 0.05 wt. % to 10 wt. %, in particular 0.1 wt. % to 5 wt. %, preferably 0.25 wt. % to 4 wt. %, more preferably 0.4 to 3.5 wt. % by weight, based on the weight of the plastic granular base material.

[0128] The base material can also comprise other additives that ensure certain properties of the yarn 2, such as UV stabilization, flame retardancy, and/or antistatic. The additives can be in the form of an additive masterbatch material. The additive masterbatch material can be mixed with the plastic granular base material and the color masterbatch material.

[0129] Preferably, the base material must not comprise any moisture or should comprise as little moisture as possible, as the moisture evaporates when the base material is melted. The evaporated moisture creates small bubbles or steam inclusions in the polymer melt, which can cause bubbles in the yarn 2 and/or fibers 3. These bubbles and/or inclusions have a negative impact on the mechanical properties and, in particular, the strength of the yarn 2 and/or fiber 3.

[0130] The melt spinning system 1 can comprise a drying device 4 for drying the base material. The drying device 4 preferably dries the base material with hot, dry air in order to accelerate the drying process and to be able to operate it economically. The drying device 4 preferably dries the base material at temperatures above 100 C., preferably at temperatures in the range from 110 C. to 160 C., more preferably in at temperatures in the range from 130 C. to 150 C. The base material is preferably dried under such conditions, that the moisture content of base material, is below 1%, preferably below 0.5%, more preferably below 0.1% after drying.

[0131] As FIG. 1 also shows, the base material can be fed to an extruder 5 directly from the drying device 4. Alternatively, it is also possible to pack the dried base material in an airtight and/or moisture-proof manner and feed it to the extruder 5 with a time delay.

[0132] The dried base material is preferably fed to the extruder 5 via a material hopper 6 in order to enable a uniform feed into the extruder 5.

[0133] The extruder 5 melts the base material and provides it as a homogeneous polymer melt, as method step b). The starting material is melted by the extruder 5 by applying thermal and mechanical energy. The polymer melt reaches a temperature above the material-dependent melting temperature. The polymer melt is preferably heated to between 30 C. and 60 C. above the melting point of the polymer used.

[0134] Instead of using an extruder 5, the homogeneous polymer melt can also be prepared using a reactor in which the plastic and/or polymer is produced.

[0135] The homogeneous polymer melt is then fed to a spinneret 7 to spin a yarn 2, as a further method step c). The spinneret 7 can have one or more than one nozzle. If the spinneret 7 has one nozzle, a monofilament can be producedi.e. a single filament and/or a single fiber yarn. If the spinneret 7 has more than one nozzle, a multifilament can be producedi.e. a multi-fiber yarn.

[0136] The properties of the fiber 3 and/or yarn 2 produced can be influenced by the pressure with which the polymer melt is forced through the spinneret 7. In order to build up a constant and sufficiently high pressure upstream of the spinneret 7, a spinning pump 8 can be connected upstream of the spinneret 7. The spinning pump 8 can be designed as a gear pump, for example. Gear pumps are suitable for building up a high pressure at a constant delivery rate.

[0137] The molten polymer is forced through the spinneret 7 under high pressure. To prevent material breakage, it is necessary to use a spinning additive.

[0138] Here and preferably, the spinning additive is self-elutable and/or self-sluicing upon washing the yarn 2 and/or fabric spun from the yarn 2 with an aqueous solution and/or the spinning additive is water-soluble.

[0139] The spinning additive can comprise at least one surface-active substance and/or surfactant, preservative, lubricant, in particular plant-based lubricant, and mixtures thereof. Reference is made to the general part of the description.

[0140] The spinning additive can be added to the base material in step a) and/or while extruding in step b). Alternatively or additionally, the spinning additive can be added to the polymer melt while and/or before spinning, in particular in step c).

[0141] Each nozzle of the spinneret 7 produces a single filament or fiber 3. The fibers 3 produced in this way pass through a cooling section 9, in which the fibers 3 are cooled by means of an air flow 10. A constant air flow 10 can be generated over the length of the cooling section 9. However, it is also possible to generate an air flow 10 that varies in the direction in which the fibers 3 are drawn off. For example, the air flow 10 can change in temperature and/or flow velocity in the direction in which the fibers 3 are drawn off in order to enable optimum cooling of the fibers 3.

[0142] The cooled fibers 3 are drawn off by means of a draw-off roller 11. One fiber or several fibers 3 can be combined into one yarn 2 by means of the draw-off roller 11.

[0143] The fibers 3 can be stretched by means of the draw-off roller 11 depending on the drawn-off speed. This aligns the molecular chains with the fiber 3 axis. This parallel alignment can lead to interactions between the individual chains, for example hydrogen bonds between neighboring molecular chains. In combination with the temperatures used, the ratio of amorphous and crystalline sub-areas in the fiber 3 can also be varied for semi-crystalline plastics. The orientation of the molecular chains improves as the drawn-off speed increases. The draw-off speed can be between 1000 m/min and 6000 m/min.

[0144] The yarn 2 can then be wound up onto spools using a winder 12. The resulting spools of yarn 2 can then be used for manufacturing fabrics 30 and/or textiles.

[0145] A stretching device 13 for additional stretching of the fibers 3 or yarn 2 can be arranged between the draw-off roller 11 and the winder 12. The yarn 2 can be conveyed via at least two successively arranged stretching rollers 14 running at different speeds. Due to the different rotational speeds of the stretching rollers 14, the fibers 3 or yarns 2 are stretched or drawn in the longitudinal direction.

[0146] The stretching process aligns the molecular chains with the fiber 3 axis. This parallel alignment can lead to further interactions between the individual chains, for example further hydrogen bonds between neighboring molecular chains. The strength of the fiber 3 is significantly increased by the stretching process. On the one hand, the strength increases due to the parallel alignment of the molecular chains to the fiber 3 axis. On the other hand, the strength increases due to interactions that occur, such as the formation of hydrogen bonds. Depending on the degree of stretching, a distinction is made between high oriented yarn 2 (HOY), low oriented yarn 2 (LOY) and partially oriented yarn 2 (POY).

[0147] Here and preferably partially oriented yarn 2 is generated.

[0148] An additional or alternative stretching can also be carried out subsequently before the yarns 2 wound onto spools are further processed. It is also possible to process the yarns 2 produced in a next step with other yarns 2 (e.g. made of elastane) to form a composite.

[0149] The yarn 2 produced can then be further processed into a fabric 30 and/or textile, in particular a flat 30 fabric, for example by weaving, knitting and/or warp knitting in a further method step d). During processing, further additives are usually used to facilitate further processing and/or to prevent fibers 3 and/or yarn 2 from tearing. Before processing into an end product, such as shirts, sweaters or shoes, the spinning additives and/or additives added during the spinning process and/or further processing must be removed from the textile.

[0150] For this purpose, the fabric is washed to remove the spinning additive and/or additives from the fabric in a further method step e).

[0151] The washing process 15 (FIG. 2) can preferably be limited to 30 minutes due to the small amount of particles to be washed out. The washing process 15 is preferably carried out at a temperature between 80 C. and 95 C., in particular at least substantially 90 C.

[0152] The ratio between the textile to be washed and water is preferably between 1:5 and 1:9, preferably between 1:6 and 1:8. This means that less water is required than when washing textiles produced by conventional dope-dyeing methods.

[0153] Here, and preferably, no detergent is required during the washing process 15, which means that the fabric can be produced in a particularly environmentally friendly manner.

[0154] FIG. 2 shows a schematic flow chart of a treatment process 16, in particular a water treatment process. The treatment process 16 is preferably designed in three stages.

[0155] The raw wastewater from the washing process is first fed into an air flotation device 17. The air flotation device 17 represents the first stage, in particular step i) of treatment process 16.

[0156] FIG. 3 shows the air flotation device 17 in detail. The air flotation device 17 preferably has a cleaning tank T for receiving and cleaning the raw wastewater. A cleaning agent is preferably added to the raw wastewater. The cleaning agent is preferable selected from flocculants, flocculation aids, clarifying agents, precipitants, coagulates, pH-regulators, and mixtures thereof.

[0157] In FIG. 3 the arrow A1 shows the filling of raw wastewater and cleaning agent into the air flotation device 17.

[0158] The raw wastewater preferably flows through the air flotation device 17. The arrow A2 in-dicates the direction of flow of the wastewater.

[0159] The cleaning agent can be added in amounts in the range of 10 g/m.sup.3 to 400 g/m.sup.3, based on the weight of washed and/or produced fabric.

[0160] The air flotation device 17 preferably has an agitator 18 to evenly mix the raw wastewater and the cleaning agent. The cleaning agent preferably begins to coagulate into small flocs 19. Pollutants, including dissociative colorants, fibers 3, spinning additives and other resi-dues, can be bound to the flocs 19.

[0161] As FIG. 3 shows, the air flotation device 17 has an air bubble generator 20. The air bubble generator 20 is designed to generate air bubbles 21. The arrow A3 shows the addition of air to generate air bubbles using the bubble generator. The air bubbles 21 can rise to the water surface due to the gravity.

[0162] A partition wall P1 is preferably provided between the agitator 18 and the air bubble generator 20, under which the raw wastewater is passed. This ensures that the raw wastewater is evenly mixed with the cleaning agent or/or flocs 19. The air bubbles 21 can then be introduced evenly into the raw wastewater mixed with the flocs 19.

[0163] The air bubbles 21 generated have a diameter of between 1 m and 10 m, preferably between 2.5 m and 8 m, and preferably between 3 m and 7 m, and or preferably in a continuous manner. As the air bubbles 21 rise to the surface, flocs 19 with which an air bubble 21 comes into contact are bound to the air bubble 21. In this way, the air bubbles 21 transport the flocs 19 and the pollutants attached to the flocs 19 to the water surface.

[0164] The air bubbles 21 bound with flocs 19 and the pollutants adhering to the flocs 19 create a foam 22 on the water surface. The foam 22 containing the flocs 19 and pollutants can be removed from the water surface by means of a scraper 23 that can be moved along the water surface as indicated by arrow A4. The foam 22 can be discharged into a collecting basin B using the scraper 23. The foam 22 can be removed from the collection basin B for further treatment, as indicated by the arrow A5.

[0165] The raw wastewater is treated by the air bubbles 21, as disclosed above. The cleaning tank T preferably comprises a second partition wall P2 under which the at least substantially partially cleaned water can be guided. The at least substantially partially cleaned water can be discharged as indicated by arrow A6.

[0166] Due to the low concentration of pollutants, a surface load between 30 m/h and 40 m/h can preferably be achieved. In the present case, the term surface load refers to the maximum hydraulic loading of the air flotation device 17, which corresponds to the minimum settling velocity of the particles/pollutants to be deposited. The surface load results from the maximum achievable flow rate of the air flotation device 17 in relation to the base area of the air flotation device 17.

[0167] Due to the low concentration of pollutants, the energy requirement for air flotation can be less than 0.1 kWh per 1000 liters of water, preferably less than 0.09 kWh per 1000 liters, more preferably less than 0.075 kWh per 1000 liters.

[0168] The foam 22 is preferably collected as described above and fed to a gravity separator 24. The pollutants and the water contained in the foam 22 can be separated from each other by means of the gravity separator 24. For this purpose, the foam 22 can be settled for up to 24 hours at a standstill. In this way, foam 22 can be separated into water and sludge, with the water and sludge settling out due to their different densities. The sludge that forms and/or settles is preferably concentrated and in particular comprises up to 10 times more pollutants than the foam 22.

[0169] The concentrated sludge contains biodegradable organic substances that are suitable for biological treatment. The ratio of Biochemical Oxygen Demand (BOD) to Chemical Oxygen Demand (COD) is preferably more than 0.3 (BOD/COD>30%).

[0170] The sludge can be decomposed and reduced in bioreactors to minimize the final solids output.

[0171] The water contained by the gravity separator 24, in particular by an additional condensa-tion step, is preferably at least essentially free of pollutants. The clean water can be fed to a water tank 25 for clean water, as FIG. 2 shows. Water containing pollutants can be fed back to the air flotation device 17.

[0172] The first step, in particular step i) of the (water) treatment process 16 of the raw wastewater by means of the air flotation device 17 preferably produces so-called gray water. The gray water can be fed to a subsequent filtration device 26, as shown in FIG. 2. The filtration device 26 preferably forms the second stage, in particular a method step ii), of the treatment process 16.

[0173] The gray water can have a value of Chemical Oxygen Demand (COD) between 1010 mg/L and 1280 mg/L and/or a concentration of Biochemical Oxygen Demand (BOD) between 250 mg/L and 280 mg/L and/or a concentration of total nitrogen (TN) between 2.0 mg/L and 2.4 mg/L and/or a concentration of total phosphorous (TP) between 1.1 mg/L and 1.3 mg/L and/or a concentration of antimony (Sb) between 0.012 mg/L and 0.02 mg/L and/or an electrical conductivity between 96 s/cm and 104 s/cm.

[0174] The Chemical Oxygen Demand (COD) is preferably determined according to the Chinese national standard GB/T 11914.

[0175] The Biochemical Oxygen Demand (BOD) is preferably determined according to the Chinese national standard HJ 505.

[0176] The concentration of biochemical total nitrogen (TN) is preferably determined according to the Chinese national standard HJ 636.

[0177] The concentration of total phosphorous (TP) is preferably determined according to the Chinese national standard GB/T 11893.

[0178] The concentration of antimony (Sb) is preferably determined according to the Chinese national standard GB/T 11893.

[0179] The filtration device 26 is preferably designed to further purify the gray water. For this purpose, the filtration device 26 preferably has sand, in particular quartz sand, for sand-filtering the gray water. However, it is also possible to use other materials for filtering the gray water.

[0180] The sand preferably has an average grain size of between 0.3 mm and 2 mm, more preferably between 0.4 mm and 1.5 mm, more preferably between 0.5 mm and 1.2 mm.

[0181] The water purified by the filtration device 26 can be fed to a water tank 27 for purified water. The purified water can be used for a further washing process 15, as FIG. 2 shows in detail. Due to the two-stage treatment process 16, the water used in the washing process 15 and subsequently purified can be reused at least 15 times and/or less than 25 times. Preferably, the purified water can be reused between 15 and 20 times.

[0182] The clean water supplied to the water tank 25 for clean water preferably contains less pollutants than the purified water supplied to the water tank 27 for purified water.

[0183] The water purified by sand filtration can have a value of Chemical Oxygen Demand (COD) between 58 mg/L and 148 mg/L and/or a concentration of Biohemical Oxygen Demand (BOD) between 28 mg/L and 37 mg/L and/or a concentration of total nitrogen (TN) between 0,009 mg/L and 0.013 mg/L and/or a concentration of total phosphorous (TP) between 0.6 mg/L and 0.8 mg/L and/or a concentration of antimony (Sb) between 0.002 mg/L and 0.004 mg/L and/or an electrical conductivity between 332 s/cm and 349 s/cm.

[0184] In this way, due to the treatment process 16 between 90% and 95% of Chemical Oxygen Demand (COD) and/or between 86% and 90% of Biochemical Oxygen Demand (BOD) and/or more than 99% of TN and/or between 40% and 45% of phosphorous (TP) and/or more than 75% of antimony (Sb) can be removed from the raw wastewater.

[0185] The filtration device 26 can reduce the concentration of remaining suspended solids (SS) in the purified water to less than 1 mg/l.

[0186] If a higher water quality is to be achieved or if the water quality achieved by the two stages of treatment process 16 does not meet the specified requirements, the purified water can be fed to a membrane filtration device 28 for further purification (FIG. 2), as a method step iii) of the treatment process 16.

[0187] The membrane filtration device 28 preferably has a membrane for reverse osmosis (RO) and/or a membrane for ultrafiltration (UF), through which the water is further purified.

[0188] The water purified by the membrane filtration device 28 can be supplied as clean water to the water tank 25 for clean water. The clean water can be fed to the washing process 15 and/or used for further processing 29 of the fabric 30.

[0189] The water enriched with pollutants resulting from reverse osmosis or ultrafiltration can be fed to a separate water treatment, which is not shown in detail in the figures.

[0190] FIG. 4 shows a colored fabric 30 obtained by a method for producing a colored yarn 2 based on synthetic fibers 3 according to a proposed method.

TABLE-US-00001 Reference Symbol List: 1 Melt spinning system 2 Yarn 3 Fiber 4 Drying device 5 Extruder 6 Material hopper 7 Spinneret 8 Spinning pump 9 Cooling section 10 Air flow 11 Draw-off roller 12 Winder 13 Stretching device 14 Stretching roller 15 Washing process 16 Water treatment process 17 Air flotation device 18 Agitator 19 floc 20 Bubble generator 21 Air bubble 22 Foam 23 Scraper 24 Gravity separator 25 Water tank 26 Filtration device 27 Water tank 28 Membrane filtration device 29 Further processing 30 Fabric A1-A6 Arrow B Basin P1 Partition wall P2 Partition wall T Cleaning tank