WO2022190131A1 - Colour stripping composition for dyed cotton textiles and method thereof - Google Patents

Colour stripping composition for dyed cotton textiles and method thereof Download PDF

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Publication number
WO2022190131A1
WO2022190131A1 PCT/IN2022/050221 IN2022050221W WO2022190131A1 WO 2022190131 A1 WO2022190131 A1 WO 2022190131A1 IN 2022050221 W IN2022050221 W IN 2022050221W WO 2022190131 A1 WO2022190131 A1 WO 2022190131A1
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Prior art keywords
stripping
dyed
cotton
minutes
gpl
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PCT/IN2022/050221
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French (fr)
Inventor
Kiruthika KANNAPPAN
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Kannappan Kiruthika
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Publication of WO2022190131A1 publication Critical patent/WO2022190131A1/en

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    • D—TEXTILES; PAPER
    • D06—TREATMENT OF TEXTILES OR THE LIKE; LAUNDERING; FLEXIBLE MATERIALS NOT OTHERWISE PROVIDED FOR
    • D06P—DYEING OR PRINTING TEXTILES; DYEING LEATHER, FURS OR SOLID MACROMOLECULAR SUBSTANCES IN ANY FORM
    • D06P5/00—Other features in dyeing or printing textiles, or dyeing leather, furs, or solid macromolecular substances in any form
    • D06P5/13—Fugitive dyeing or stripping dyes
    • D06P5/131—Fugitive dyeing or stripping dyes with acids or bases
    • D—TEXTILES; PAPER
    • D06—TREATMENT OF TEXTILES OR THE LIKE; LAUNDERING; FLEXIBLE MATERIALS NOT OTHERWISE PROVIDED FOR
    • D06P—DYEING OR PRINTING TEXTILES; DYEING LEATHER, FURS OR SOLID MACROMOLECULAR SUBSTANCES IN ANY FORM
    • D06P3/00—Special processes of dyeing or printing textiles, or dyeing leather, furs, or solid macromolecular substances in any form, classified according to the material treated
    • D06P3/58—Material containing hydroxyl groups
    • D06P3/60—Natural or regenerated cellulose
    • D06P3/66—Natural or regenerated cellulose using reactive dyes

Definitions

  • the present invention relates to the field of textiles. More particularly, it relates to fabric treatment process for stripping colour in reactive dyed fabrics /recycled dyed cotton yarns.
  • the present invention has been developed with non-hazardous chemicals to achieve level dyeing in fabrics made with blended reactive dyed recycled cotton yams.
  • Cotton agriculture also has a significant impact on the environment and is the highest or second highest agricultural use of pesticides, herbicides and fungicides.
  • Our society is becoming increasingly aware of the severity of our environmental problems and in particular the scarcity of appropriate landfill sites, and the deleterious impact of waste incineration, industrial discharges, and the use of pesticides and other chemicals in agriculture.
  • it is becoming increasingly important to reduce the amount of waste we generate, recycle more of the waste that is generated, and reduce or eliminate as much toxic chemical use as possible.
  • Sulfite salt is selected like as Sodium sulfite, Sodium bisulfite, Calcium sulfite, Potassium sulphite Sodium hydroxymethane sulfmate - Organic.
  • CN105256619B cationic dye dyed acrylic fabric - Stripping agent preparation Higher fatty acid salt (40%-50%), Wetting agent (5%-10%), Dispersing agent (10%-15%) Higher fatty acid salt is C 16-08 the sodium salt of fatty acid, Wetting agent is anionic surfactant and the Dispersing agent is one of the polyether type non-ionic surfactant and polyvinyl alcohol Higher fatty acid salt is C 16-08 the sodium salt of fatty acid - Organic Prepared stripping agent 4 - 8 g/1
  • Penetrating agent is any one of alkyl benzene sulfonate, aliphatic hydrocarbon and olefin sulfonate, aliphatic alcohol and aliphatic alcohol ether sulfate, aliphatic alcohol and aliphatic alcohol polyoxyethylene ether phosphate.
  • Dispersant is any one of the polyethylene glycol, polyether nonionic surfactant, polyvinylpyrroliodine, polyvinyl alcohol and poly acrylic acid Penetrating agent, Dispersant agent - Organic Cotton Jean: Caustic soda 2-3 g/1, Stripping agent 4-5 g/1, Peregal 0 3-5 g/1, Sodium hydrosulfite 4-5 g/1. Cotton denim: Sodium hydrosulfite 4 g/1, Caustic soda 2g/l, Peregal O 5 g/1, Stripping agent 4.5 g/1.
  • Cotton Jean Adding water with the required volume according to the weight of the fabric according to the bath ratio of l:(20-30), heating to 85-95 deg C, Sequentially adding 2-3 g/1 of caustic soda, 4-5 g/1 of stripping agent, 3-5 g/1 of peregal O and 4- 5 g/1 of sodium hydrosulfite, stirring to dissolve the agents, and then adding the fabric, stirring, circularly or ultrasonically vibrating, preserving heat for 40-50 min, draining and washing with clear water for 2-3 mins.
  • Cotton denim 4 g/1 of sodium hydrosulfite, 2g/l of caustic soda, 5 g/1 of peregal O, 4.5 g/1 of stripping agent, 1:30 of bath ratio, 90 deg C of temperature and 40 mins of time Sodium hydrosulfite, Caustic soda - Hazardous Cotton Jean: 85-95 deg C, Cotton Denim: 90 deg C Cotton Jean: 40-50 mins, Cotton Denim: 40 mins MUR 1:20 to 1:30.
  • stripping composition for reactive dyed fabrics / reactive dyed recycled yams stripping composition comprising of:
  • Dispersing agent - 0.5 gpl; and stripping agent wherein the composition essentially consists of stripping agent 2-propenoic acid, homopolymer based polymer in a weight ratio of 3.0% to 7.0% v/v. on weight of fabric.
  • Figure 1 illustrates the stripping efficiency - recipe reduction - 1. After conventional stripping recipe % and 2. After innovative stripping recipe %.
  • Figure 2 illustrates stripping efficiency - % of reduction - conventional stripping and % of reduction - innovative stripping.
  • SPECTROPHOTOMETER Make: Mecbeth/Xrite Model: Color i7 Version: 9.8.20 Aperture Size: 25MM LAV 17MM 10MM - MAV 6MM - SAV
  • Figure 3 illustrates Terry fabric strength loss comparison lbs- length.
  • Figure 4 illustrates Yellow dyed fabric before stripping. Color values were measured using COLOR SPECTROPHOTOMETER: Make: Mecbeth/Xrite Model: Colori7 Version: 9.8.20 Aperture Size: 25MM LAV 17MM 10MM - MAV. 6MM - SAV Figure 5 Yellow dyed fabric after conventional stripping - color value illustrates Figure 6 illustrates Yellow dyed fabric after innovative stripping - color value
  • Figure 7 illustrates RED dyed fabric before stripping - color value
  • Figure 8 illustrates RED dyed fabric after conventional stripping - color value
  • Figure 9 illustrates RED dyed fabric after innovative stripping - color value
  • Figure 10 illustrates Dark RED dyed fabric before stripping - color value
  • Figure 11 illustrates Dark RED dyed fabric after conventional stripping - color value
  • Figure 12 illustrates Dark RED dyed fabric after innovative stripping - color value
  • Figure 13 illustrates NAVY dyed fabric before stripping - color value
  • Figure 14 illustrates Navy dyed fabric after conventional stripping - color value
  • Figure 15 illustrates Navy dyed fabric after innovative stripping - color value
  • Figure 16 illustrates Dark BLUE dyed fabric before stripping - color value
  • Figure 17 illustrates Dark blue dyed fabric after conventional stripping - color value
  • Figure 18 illustrates Dark blue dyed fabric after innovative stripping - color value
  • Figure 19 illustrates Turquoise blue dyed fabric before stripping - color value
  • Figure 20 illustrates Turquoise blue fabric after conventional stripping - color value
  • Figure 21 illustrates Turquoise blue dyed fabric after innovative stripping - color value
  • the present invention relates to a field of textile and the manufacture of quality fabrics from dyed dyed recycled yams, and in particular relates to the utilization of inexpensive cotton waste materials (used cloths / fabrics) as the source material along with virgin cotton in a process for making recycled cotton yarn.
  • This invention is the use of any and all of these wastes for the manufacture of yarns of high enough quality, and thus higher value, for use in the garment and terry towel manufacturing.
  • this invention involves the use of virgin cotton and fiber from post-consumer dyed fabric / apparel waste in the manufacture of high quality yarns using a process that is economically feasible on a commercial scale.
  • the process of the subject invention involves making finer count - being 8 count and above — cotton yams either 10 / 90% to 50 / 50% completely from used fabric recycled cotton using a combination of virgin and dyed recycled cotton, to produce yarns of quality suitable for the terry products and related items.
  • the principle of this invention is that through processing the waste fibres differently, and mixing with virgin cotton, by twisting the yarn made from these fibres differently, count yams can be made from blends of 10 / 90 to 50/ 50 recycled cotton / virgin cotton.
  • post - consumer shoddy can also be used when blended with fibres of virgin cotton to make the yarns suitable for terry industry.
  • Ionic nature non-ionic; pH of 1% solution - 11 ⁇ 2;
  • Stability Stable to dilute acid and dilute alkalis.
  • the product of the present invention gives excellent stripping agent for cotton fabric/ fiber / yarn dyed with reactive dye. It gives complete stripping of dyes as compared against conventional method of stripping using caustic soda and hydros. This innovative chemical will prevent fabric damage, which is generally observed when stripping is done by conventional method using caustic sod and hydrose.
  • the stripped fabric will have same whiteness in the case of virgin cotton portion and recycled dyed yarn portion due to this innovative stripping process leading to uniform solid dyeing.
  • terry fabric In the cotton textile industry, using the conventional process of pre-treatment of terry fabric involves desizing / scouring / half-bleaching to make it suitable for dyeing with solid even dyeing.
  • Output is the terry towel with 100% solid even colouring (shade as desired).
  • the present invention relates to the processing sequence terry fabric produce with dyed recycled dyed (RCD) / virgin cotton (VC) pile / ground / weft in a general blend ratio may be in the range of 10/90% to 50/50%. Recycled dyed cotton / virgin cotton blend yarn will have different colours like blue, red, navy mixtures of colours etc.
  • grey fabric needs to be pre-treated with desizing/scouring/half bleaching to make it suitable for dyeing with basic whiteness in the range of 60 - 65.
  • the present invention relates to development of new process sequence to make the terry fabric produced with recycled dyed / virgin suitable for dyeing as like 100% virgin cotton with solid even dyeing as like terry towels produced with 100% virgin cotton (i.e., no difference in colouring between the virgin cotton and the recycled dyed cotton).
  • recycled dyed cotton / virgin cotton blend yarn may be used in pile, ground and warp depends on the yarn quality / blend ratio and strength.
  • New process sequence for terry towels produced with recycled cotton / virgin cotton blend to make the fabric suitable for solid dyeing as like is 100% virgin cotton.
  • New process sequence for terry towels produced with RCD /VC blend fabric (Terry fabric with recycled cotton / virgin cotton blend in pile, ground, weft yarn with a blend ratio of 50% RCD / 50% VC to 10% RCD / 90% VC).
  • Output is the terry towel with 100% solid even dyeing as like terry towels with 100% virgin cotton.
  • Treatment of terry fabric with virgin cotton / RCD in pile in soft flow dyeing machine - material to liquor ratio is 1: 5.5.
  • Desizing both pile yam and ground yarns are sized using natural / synthetic sizing chemicals.
  • 1st step is to desize the fabric with 1.0 gpl enzymatic desizing agent / 1 gpl cationic wetting gent at 60 degree Celsius for 30 minutes.
  • Propenoic acid 5.0 - 7.0% OWF (on weight of fabric) / Depends on the colour depth of RCD; Fiber dispersing agent 0.5 gpl;
  • Time - 20 - 30 minutes depends on colour depth and drain.
  • New innovative process has been established for producing terry fabric has yarn with a blend of recycled dyed cotton / virgin cotton blend with solid even dyeing.
  • Degradability of Stripping component 100 % Biodegradable as this composition has GOTS approved organic components. Colour removing efficiency: 90 -95 %. (Yellow 90 % - 95 %) and other components like Red & Blue will be 95 -100 %.
  • Stripping Agent Organic - GOTS approved 2 Propionic acid Homo polymer - Non hazardous Stripping agent
  • Propionic acid Homopolymer is a stripping agent for cotton fabric dyed with reactive dye. It gives excellent stripping of dyes as compared against conventional method of stripping using caustic and hydrose. 2 Propionic acid Homopolymer will prevent fabric damage, which is generally observed when stripping is done by conventional method using caustic and hydrose.
  • Non foaming Wetting, Scouring and detergent designed for the wetting, scouring and bleaching operation of 100 % cotton knits, in high turbulence equipments like jet and softflow dyeing machines.
  • Hemitol SRW can be added undiluted to the application baths. Feed baths should be stirred after prolonged standing.
  • HT Bleach can also be done using the above recipe at 110°C for 30 min. After bleaching one Hot wash at 90°C and cold wash with neutralizing using Acetic Acid should be given. To ensure a trouble-free subsequent dyeing we strong recommend an after treatment with Sarakol PDR 9 Soap cum dispersing agent)
  • Sarakol-PDR is a concentrated polymeric compound which can be readily dissolved to obtain stable solution. Sarakol-PDR is recommended in reactive dyeing by exhaust method. In case of reactive dyes which are having low solubility in presence of salt and alkali and when liquor ratio is low there could be precipitation of dyes during the dyeing, leading to poor colour yield as well as precipitation of dyes on substrate and machine. Addition of Sarakol-PDR overcomes this problem due to its excellent dispersing action. Calcium and Magnessium impurities in the dyebath could also lead to precipitation of dyes as well as poor washing off of hydrolysed dyes at the end of dyeing.
  • Sarakol-PDR Due to its chelating action, Sarakol-PDR prevents such precipitation and also helps in easy removal of hydrolysed reactive dyes at the end of dyeing operation. Sarakol-PDR is also recommended as a washing off agent for reactive dyes in batch operation as well as in continuous operation.
  • Residual salt concentration should be less than 2 g/1 before soaping.
  • Storage Store in cool, ventilated shed away from heat and direct sunlight. Storage temperature should not exceed 35 deg C. Close lids firmly to avoid contact with air and moisture.

Abstract

The present invention relates to fabric treatment process and composition for stripping colour in recycled dyed cotton yarns. The present invention has been developed with non-hazardous chemicals to achieve level dyeing in fabrics made with blended recycled cotton yarns. The stripping composition comprises of wetting agent – 0.3 to 0.5 gpl; Dispersing agent – 0.5 gpl; and stripping agent essentially consisting 2- propenoic acid, homopolymer based polymer in a weight ratio of 3.0% to7.0% v/v on weight of fabric.

Description

COLOUR STRIPPING COMPOSITION FOR DYED COTTON TEXTILES AND
METHOD THEREOF
FIELD OF THE INVENTION
The present invention relates to the field of textiles. More particularly, it relates to fabric treatment process for stripping colour in reactive dyed fabrics /recycled dyed cotton yarns. Advantageously, the present invention has been developed with non-hazardous chemicals to achieve level dyeing in fabrics made with blended reactive dyed recycled cotton yams.
BACKGROUND OF THE INVENTION
In the cotton textile industry, using the current processes of producing finished apparel and related goods from raw virgin cotton, 20-49% of the original fibre in the raw material is typically separated as waste in the various processes. Once produced the finished goods have a limited life; when they have ended their useful life they are possibly used as rags for a brief period and then typically discarded to end-up in a landfill or waste incineration facility.
Cotton agriculture also has a significant impact on the environment and is the highest or second highest agricultural use of pesticides, herbicides and fungicides. Our society is becoming increasingly aware of the severity of our environmental problems and in particular the scarcity of appropriate landfill sites, and the deleterious impact of waste incineration, industrial discharges, and the use of pesticides and other chemicals in agriculture. As a result of this increasing awareness it is becoming increasingly important to reduce the amount of waste we generate, recycle more of the waste that is generated, and reduce or eliminate as much toxic chemical use as possible.
Type of waste:
Only a portion (in some cases very small) of each waste type is being recycled or reused. Much of the cotton waste goes directly to landfills and a large proportion of the gin motes are being ploughed under in farmer’s fields to eliminate the increasing tipping fees associated with commercial waste disposal.
While there are potential uses for these wastes, unfortunately not all of these wastes are being reused or recycled. Even when these materials are recycled or reused, most of the uses for these wastes are for relatively low value goods which often have a very short useful life. If a higher value and more durable use is found for these wastes, then much more of these wastes will be used— which will reduce the waste stream into landfills and waste incineration facilities, and reduce the amount of pesticides, herbicides, fungicides, and other chemicals used in growing and processing cotton by decreasing the amount of virgin cotton needed for the apparel and related industries.
While most of the post consumer dyed waste materials that are recycled to make these high quality have already been reused or recycled to some extent in other products, most of the uses for these wastes are for very low value goods and only a portion of the wastes are being reused or recycled. While some of these wastes are also being recycled into new yams, these yarns are typically coarse count yarns suitable producing terry fabric.
US05/961.728 dyed textile fabric (reactive, direct, vat, polyester, nylon and acrylic fabric) Aqueous Solution Preparation: Sodium hydroxymethane sulfmate (0.5%-3.5%), Ammonium salt (1%- 3.5%),& Sulfite salt (l%-3.5%) and Wetting agent of 0.2% long chain phosphate alcohol maintained atleast 60 deg C - 88 deg C and pH from about 5 - 9 Ammonium salt is selected like as Ammonium sulfate, Ammonium chloride, Ammonium carbonate, Ammoinum bicarbonate, an organic ammonium salt. Sulfite salt is selected like as Sodium sulfite, Sodium bisulfite, Calcium sulfite, Potassium sulphite Sodium hydroxymethane sulfmate - Organic. Ammonium Salt - Inorganic. Sulfite salt - Inorganic Aqueous Solution Preparation: Sodium hydroxymethane sulfmate (0.5%-3.5%), Ammonium salt (l%-3.5%), & Sulfite salt (l%-3.5%) and Wetting agent of 0.2% long chain phosphate alcohol Prepared aquoes solution is heated at 60 deg C and adding the fabric and then temperature raising upto 88 deg C (ldeg / mins) run 30 minutes. pH 5 - 9 temperature 88 deg C time 30.
CN105256619B cationic dye dyed acrylic fabric - Stripping agent preparation: Higher fatty acid salt (40%-50%), Wetting agent (5%-10%), Dispersing agent (10%-15%) Higher fatty acid salt is C 16-08 the sodium salt of fatty acid, Wetting agent is anionic surfactant and the Dispersing agent is one of the polyether type non-ionic surfactant and polyvinyl alcohol Higher fatty acid salt is C 16-08 the sodium salt of fatty acid - Organic Prepared stripping agent 4 - 8 g/1
1. Weighing the components according to the weight percentage, and preparing a stripping agent;
2. Adding water into the stripping agent to prepare stripping liquid with the stripping agent content of 4-8 g/1, Bath ratio 1: (20-30). 3. Add Fabric and then raise upto 100 deg C (2-3 deg C/ min) stripping for 20 - 30 mins. After rinsing the fabric by using hot water at the temperature 60- 70 deg C, and then rinsing the fabric by using cold water to finish the stripping. (For light colors 4-6 g/1 stripping agent and Dark colors 6-8 g/1 stripping agent used). STRIPPING RATE 40 - 60% TEMPERATURE 100 deg C TIME 20-30 MUR 1:20 to 1:30.
104420371A1CN cotton dyed by reactive, wool and silk dyed by acid dye - CY-770 water solution, Penetrant JFC or CY-7P and feeding CY-730 and a catalyst, and the dosage of strong reducing agent is 1/5 that of sodium hydrosulfite, sodium hydrosulfite - Inorganic Dosage ratio of CY-730 to CY-770 is 1:1.9 Soaking fabric to be stripped in CY-770 water solution and penetrant JFC or CY-7P at 40 deg C, and treating for 10 mins; adding CY730, heating to 95 - 100 deg C (80-85 deg C for wool and silk), and soaking for 30-40 mins (60 mins for wool and silk after 80-85 deg C; After stripping, washing with hot water at 80 deg C for 10-15 mins, and again washing with cold water. Sodium hydrosulfite - Hazardous Cotton dyed by reactive 95 - 100 deg C, Wool and Silk dyed by acid dye 80 - 85 deg C Cotton dyed by reactive 30 - 40 mins, Wool and Silk dyed by acid dye 60 mins.
CN102747622B indigo dyed pure cotton jean - Stripping agent: 5-10% of a Penetrating agent, 20-25% of a dispersant agent and the balance of water. Penetrating agent is any one of alkyl benzene sulfonate, aliphatic hydrocarbon and olefin sulfonate, aliphatic alcohol and aliphatic alcohol ether sulfate, aliphatic alcohol and aliphatic alcohol polyoxyethylene ether phosphate. Dispersant is any one of the polyethylene glycol, polyether nonionic surfactant, polyvinylpyrroliodine, polyvinyl alcohol and poly acrylic acid Penetrating agent, Dispersant agent - Organic Cotton Jean: Caustic soda 2-3 g/1, Stripping agent 4-5 g/1, Peregal 0 3-5 g/1, Sodium hydrosulfite 4-5 g/1. Cotton denim: Sodium hydrosulfite 4 g/1, Caustic soda 2g/l, Peregal O 5 g/1, Stripping agent 4.5 g/1. Cotton Jean: Adding water with the required volume according to the weight of the fabric according to the bath ratio of l:(20-30), heating to 85-95 deg C, Sequentially adding 2-3 g/1 of caustic soda, 4-5 g/1 of stripping agent, 3-5 g/1 of peregal O and 4- 5 g/1 of sodium hydrosulfite, stirring to dissolve the agents, and then adding the fabric, stirring, circularly or ultrasonically vibrating, preserving heat for 40-50 min, draining and washing with clear water for 2-3 mins. For Cotton denim: 4 g/1 of sodium hydrosulfite, 2g/l of caustic soda, 5 g/1 of peregal O, 4.5 g/1 of stripping agent, 1:30 of bath ratio, 90 deg C of temperature and 40 mins of time Sodium hydrosulfite, Caustic soda - Hazardous Cotton Jean: 85-95 deg C, Cotton Denim: 90 deg C Cotton Jean: 40-50 mins, Cotton Denim: 40 mins MUR 1:20 to 1:30.
The Swedish School of Textiles “Methods for Removing Colour from Polyester and Cotton Blended Textile Waste” by Hedvig Magnusson & Adina Lothwall, Discusses about the conventional color stripping recipes for Poly ester / cotton blend fabrics. Cited chemicals are chlorine and Hydrogen peroxide both are hazardous in nature Dyes used for cotton is different from dyes used for Poly ester. Both dyes needs individual stripping recipes. Whereas the present patent invention describes the recipe which is non hazardous replacing conventionally used caustic soda and sodium hydrosulfite. Chemicals used are biodegradable.
Springer “Color stripping of reactive-dyed cotton fabric in a UV/sodium hydrosulfite system with a dipping manner at low temperature” by Fang-Ne He. Xiang Li. Meng-Ke Zhu. Jun-Hui Hu. Yu-Ji Yuan. Can-Can Li. Jia-Jie Long, Discusses about the stripping composition with UV/Sodium hydrosulfite. Sodium hydrosulfite is hazardous in nature. UV is replacing sodium hydroxide. Whereas the present patent invention describes the recipe which is non hazardous replacing conventionally used caustic soda and sodium hydrosulfite. Chemicals used are biodegradable.
Hence, there exists a need for an efficient environment friendly process for stripping the colour from dyed recycled cotton yarns.
SUMMARY OF THE INVENTION
One or more of the problems of the conventional prior arts may be overcome by various embodiments of the present invention.
It is the primary aspect of the present invention to provide stripping composition for reactive dyed fabrics / reactive dyed recycled yams stripping composition, comprising of:
Wetting agent - 0.3 to 0.5 gpl;
Dispersing agent - 0.5 gpl; and stripping agent, wherein the composition essentially consists of stripping agent 2-propenoic acid, homopolymer based polymer in a weight ratio of 3.0% to 7.0% v/v. on weight of fabric.
It is another aspect of the present invention to provide a dye stripping composition for recycled reactive dyed cotton yarns, comprising of: wetting agent — 0.5 — 1.0 g/1 ; dispersing agent - 0.5 - 1.0 g/1; and stripping agent - 4-6 g/1, wherein the stripping agent is 2-propionic acid homopolymer. It is another aspect of the present invention to provide a dye stripping composition for reactive dyed fabrics / recycled dyed cotton yarns, wherein the wetting agent is like a blend of alkoxalate in aqueous medium - non-ionic product.
It is another aspect of the present invention to provide a dye stripping composition for recycled cotton yams, wherein the dispersing agent is like concentrated polymeric compound.
It is another aspect of the present invention to provide a dye stripping composition for reactive dyed fabric / recycled dyed cotton yarns, wherein the pH of the composition is 4.0 to 5.0.
It is another aspect of the present invention to provide a method for stripping reactive dye from dyed fabrics / fabrics produced with recycled dyed cotton yarns, comprising of the steps: desizing of the dyed recycled yam for twice at 60 degree Celsius for 30 minutes; hot wash at 80 degree Celsius for a period of 10 minutes with 1 gpl dispersing agent followed by cold wash for 10 minutes; colour stripping process characterized in that comprising the steps of: treating with 0.3 to 0.5 % detergent cum dispersing agent at 95 degree Celsius for 10 minutes; adjust the pH to 4 to 4.5; add 3 to 5.0 % of 2-Propenoic acid homopolymer, raise the temperature to 95 degree Celsius for 20 - 30 minutes and drain; hot wash at 80 degree Celsius with detergent cum dispersing agent for 10 minutes; scouring / half bleaching at 95 degree Celsius for 30 minutes; hot wash at 80 degree for 15 minutes with 0.5 gpl detergent cum dispersing agent; hot wash at 70 degree Celsius for 10 minutes; neutralization with glacial acetic acid 0.3 gpl for 15 minutes; and followed by treating with Peroxide killer 0.05 gpl and bipolishing 0.3 gpl for 20 minutes.
It is another aspect of the present invention to provide a method for stripping fabrics dyed with reactive dyes / dyed recycled cotton yams, wherein the scouring / half bleaching agent comprises of Caustic soda flakes - 3.0 gpl; Hydrogen peroxide - 3.0 gpl; Wetting agent - 0.5 gpl; and Organic based stabilizer - 0.3 gpl. It is another aspect of the present invention to provide a method for stripping reactive dye from fabric comprising recycled dyed cotton / virgin cotton blend yarn in a blend ratio of 50 / 50 % to 10 / 90 %.
It is another aspect of the present invention to provide a method for stripping reactive dye from recycled cotton yarns, comprising of the steps: adding water 1:6; then adding the fabric; add chemicals: wetting agent 0.5 - 1.- g/1, dispersing agent - 0.5 - 1.0 g/1, and stripping agent 4-6 g/1; adjust the pH 4.0 - 5.0; temperature raise upto 95 degree Celsius; hold 20 - 30 mins; hot wash at 80 degree Celsius run 10 minutes; hot wash at 70 degree Celsius run 10 minutes; and cold wash at 40 degree Celsius run 10 minutes.
It is another aspect of the present invention to provide a method for stripping reactive dye from reactive dyed fabric / dyed recycled cotton yarns, wherein the process parameters includes pH - 4.0 - 5.0, temperature - 95 degree Celsius, time: 20 - 30 minutes, M:LR- 1:6.
BRIEF DESCRIPTION OF THE DRAWINGS
Figure 1 illustrates the stripping efficiency - recipe reduction - 1. After conventional stripping recipe % and 2. After innovative stripping recipe %.
Figure 2 illustrates stripping efficiency - % of reduction - conventional stripping and % of reduction - innovative stripping. Using SPECTROPHOTOMETER: Make: Mecbeth/Xrite Model: Color i7 Version: 9.8.20 Aperture Size: 25MM LAV 17MM 10MM - MAV 6MM - SAV
Figure 3 illustrates Terry fabric strength loss comparison lbs- length.
Figure 4 illustrates Yellow dyed fabric before stripping. Color values were measured using COLOR SPECTROPHOTOMETER: Make: Mecbeth/Xrite Model: Colori7 Version: 9.8.20 Aperture Size: 25MM LAV 17MM 10MM - MAV. 6MM - SAV Figure 5 Yellow dyed fabric after conventional stripping - color value illustrates Figure 6 illustrates Yellow dyed fabric after innovative stripping - color value
Figure 7 illustrates RED dyed fabric before stripping - color value
Figure 8 illustrates RED dyed fabric after conventional stripping - color value
Figure 9 illustrates RED dyed fabric after innovative stripping - color value
Figure 10 illustrates Dark RED dyed fabric before stripping - color value
Figure 11 illustrates Dark RED dyed fabric after conventional stripping - color value
Figure 12 illustrates Dark RED dyed fabric after innovative stripping - color value
Figure 13 illustrates NAVY dyed fabric before stripping - color value
Figure 14 illustrates Navy dyed fabric after conventional stripping - color value
Figure 15 illustrates Navy dyed fabric after innovative stripping - color value
Figure 16 illustrates Dark BLUE dyed fabric before stripping - color value
Figure 17 illustrates Dark blue dyed fabric after conventional stripping - color value
Figure 18 illustrates Dark blue dyed fabric after innovative stripping - color value
Figure 19 illustrates Turquoise blue dyed fabric before stripping - color value
Figure 20 illustrates Turquoise blue fabric after conventional stripping - color value
Figure 21 illustrates Turquoise blue dyed fabric after innovative stripping - color value
DETAILED DESCRIPTION OF THE INVENTION
The present invention relates to a field of textile and the manufacture of quality fabrics from dyed dyed recycled yams, and in particular relates to the utilization of inexpensive cotton waste materials (used cloths / fabrics) as the source material along with virgin cotton in a process for making recycled cotton yarn.
This invention is the use of any and all of these wastes for the manufacture of yarns of high enough quality, and thus higher value, for use in the garment and terry towel manufacturing.
Specifically, this invention involves the use of virgin cotton and fiber from post-consumer dyed fabric / apparel waste in the manufacture of high quality yarns using a process that is economically feasible on a commercial scale.
The process of the subject invention involves making finer count - being 8 count and above — cotton yams either 10 / 90% to 50 / 50% completely from used fabric recycled cotton using a combination of virgin and dyed recycled cotton, to produce yarns of quality suitable for the terry products and related items. The principle of this invention is that through processing the waste fibres differently, and mixing with virgin cotton, by twisting the yarn made from these fibres differently, count yams can be made from blends of 10 / 90 to 50/ 50 recycled cotton / virgin cotton. By processing used clothing differently to open the fabric up with less breakage and better parallel alignment of fibres, post - consumer shoddy can also be used when blended with fibres of virgin cotton to make the yarns suitable for terry industry.
New process for complete stripping of colour from recycled dyed cotton / cotton blend:
This is an innovative non-hazardous process based on chemical 2-propenoic acid, homopolymer based polymer.
Chemical properties:
Physical appearance: white to off white granules;
Ionic nature: non-ionic; pH of 1% solution - 11±2;
Miscibility: soluble with water;
Compatibility: compatible with anionic, cationic and non-ionic products;
Stability: Stable to dilute acid and dilute alkalis.
The product of the present invention gives excellent stripping agent for cotton fabric/ fiber / yarn dyed with reactive dye. It gives complete stripping of dyes as compared against conventional method of stripping using caustic soda and hydros. This innovative chemical will prevent fabric damage, which is generally observed when stripping is done by conventional method using caustic sod and hydrose.
Application:
Stepwise procedure for achieving best stripping of reactive dyes from dyed fabric /recycled dyed cotton yam
Treat with 0.3 to 0.5% detergents cum dispersing agent at 95 degree Celsius for 10 minutes. Adjust the pH to 4 to 4.5, add 3 to 5.0 % of 2-propenoic acid homopolymer, raise the temperature to 95 degree Celsius for 20 - 30 minutes, drain, and followed by hot wash at 80 degree Celsius for 10 minutes and drain.
98-100% of red and blue dyes component and 95% of yellow dye component in the dyed fabric / recycled dyed yarn will get stripped / removed according to the procedure of the present invention. Thus, the stripped fabric will have same whiteness in the case of virgin cotton portion and recycled dyed yarn portion due to this innovative stripping process leading to uniform solid dyeing.
In the cotton textile industry, using the conventional process of pre-treatment of terry fabric involves desizing / scouring / half-bleaching to make it suitable for dyeing with solid even dyeing. Process sequence for terry fabric produced with 100% virgin cotton, i.e., terry fabric with 100% virgin cotton in pile ground and weft, involves Grey fabric - desizing - Scouring - half bleaching - dyeing - after treatment - finishing, Machine - soft flow dyeing machine. Output is the terry towel with 100% solid even colouring (shade as desired).
The present invention relates to the processing sequence terry fabric produce with dyed recycled dyed (RCD) / virgin cotton (VC) pile / ground / weft in a general blend ratio may be in the range of 10/90% to 50/50%. Recycled dyed cotton / virgin cotton blend yarn will have different colours like blue, red, navy mixtures of colours etc.
In general, grey fabric needs to be pre-treated with desizing/scouring/half bleaching to make it suitable for dyeing with basic whiteness in the range of 60 - 65.
The present invention relates to development of new process sequence to make the terry fabric produced with recycled dyed / virgin suitable for dyeing as like 100% virgin cotton with solid even dyeing as like terry towels produced with 100% virgin cotton (i.e., no difference in colouring between the virgin cotton and the recycled dyed cotton).
According to an embodiment of the present invention, recycled dyed cotton / virgin cotton blend yarn may be used in pile, ground and warp depends on the yarn quality / blend ratio and strength.
1. Pile (blend ratio of 50 / 50% to 10/90%)
2. Ground yarn / weft yarn - (blend ratio of 50/50% to 10/90%)
Development of new process for terry towels produced with recycled cotton / virgin cotton blend to make the fabric suitable for solid dyeing as like is 100% virgin cotton. New process sequence for terry towels produced with RCD /VC blend fabric. (Terry fabric with recycled cotton / virgin cotton blend in pile, ground, weft yarn with a blend ratio of 50% RCD / 50% VC to 10% RCD / 90% VC). Terry fabric RCD/VC grey fabric:
1. Desizing - 2times 2. Hot wash
3. Stripping of colour in the recycled dyed yarn in pile, ground, weft using innovative non- hazardous 2-propenoic acid homopolymer followed by half bleaching
4. Dyeing - After treatment and finishing.
Output is the terry towel with 100% solid even dyeing as like terry towels with 100% virgin cotton.
Innovative process sequence according to the present invention, involves
1. Treatment of terry fabric with virgin cotton / RCD in pile in soft flow dyeing machine - material to liquor ratio is 1: 5.5.
2. Desizing; both pile yam and ground yarns are sized using natural / synthetic sizing chemicals. 1st step is to desize the fabric with 1.0 gpl enzymatic desizing agent / 1 gpl cationic wetting gent at 60 degree Celsius for 30 minutes.
3. Hot wash at 80 degree Celsius for 10 minutes with dispersing agent followed by cold wash for 10 minutes.
4. Innovative stripping (for dyed fiber content) for the complete colour removal from cotton / RCD pile yarn using innovative chemicals:
Chemicals used:
Wetting agent - 0.5 gpl;
Propenoic acid 5.0 - 7.0% OWF (on weight of fabric) / Depends on the colour depth of RCD; Fiber dispersing agent 0.5 gpl;
Temperature - 95 degree Celsius; pH - 4.0 - 4.5 using acetic acid;
Time - 20 - 30 minutes depends on colour depth and drain.
5. Hot wash at 80 degree Celsius with detergent cum dispersing agent for 10 minutes.
6. Conventional scouring / half bleaching for the virgin grey cotton content Caustic soda flakes - 3.0 gpl;
Hydrogen peroxide - 3.0 gpl;
Wetting agent - 0.5 gpl;
Organic based stabilizer - 0.3 gpl;
Temperature - 95 degree Celsius;
Time - 30 minutes. Hot wash at 80 degree Celsius for 15 minutes with 0.5 gpl detergent cum dispersing agent.
7. Hot wash at 70 degree Celsius for 10 minutes;
8. Neutralization with 0.3 glacial acetic acid for 15 minutes;
9. Peroxide killer 0.05 gpl and bipolishing 0.3 gpl for 20 minutes.
10. Now, the terry fabric with whiteness index of 60 - 65 is ready for dyeing. RFD scoured fabric parameters:
Whiteness index - 60 - 65 on CIE scale;
Residual peroxide - Nil;
Core alkali- Nil;
Residual size - Nil.
Hemito! SRW - 1 gpl
Serakol PDR 0.5 gpl
Finostrip NS - 6 gpl (Derivative of propionic acid) pH Maitain 4.0 - 4.5
Raise the temperature up to 95 deg.C for 20 mins, Drain.
Again add Finostrip NS - 4 gpl run with 95 deg.C for 20 mins, Drain.
2. GOTS approved chemicals used in the invention: Ref Attachment.
1. Hemitol SRW
2. Finostrip NS
3. Serakol PDR
3. Wetting and dispersing agent nsed in the invention:
Wetting agent - Hemitoi SRW Dispersing agent - Serakol PDR
In summary,
1. Collection of used reactive dyed cloth and converting into fibers (Recycled dyed cotton fiber - RCD) 2. Blending the RCD with virgin cotton fiber (10% / 90% to 50% / 50%)
3. Producing pile/ground/weft yarn using this blend.
4. Production of terry using this yam.
5. Since virgin cotton along with RCD have two different colours to dye solid colour is very difficult.
6. New innovative process method has been developed with non-hazardous chemical to achieve level dyeing.
Conventional stripping of colour in the terry fabric having recycled dyed yam is carried out by means of the following sequence:
I. Caustic soda - 4 to 6 gpl, sodium hypo sulphite (hydros) - 6-10 gpl and wetting cum dispersing agent - 1.0 gpl at temperature of 80 degree Celsius for time period 30 minutes; Hot wash at 80 degree Celsius with soaping cum dispersing agent for 10 minutes; Hot wash at 80 degree Celsius; Neutralization with acetic acid 1.0 gpl for 20 minutes; Dark and very dark colours need double time stripping.
With conventional process sequence, 90% of red and blue component and 70%- 80 % yellow component in the reactive dyed fabric will get removed i.e., 10% of red and blue and 20 -30% of yellow of overall composition remains in the fabric. Note: Sodium hydrosulphite is hazardous chemical and this will strip the reactive colour only in the presence of caustic soda at a pH of
II.0 and above at high temperature i.e., after stripping and scouring of terry towels produced with RCD / VC yarn will have two different whiteness / colour - virgin cotton portion will have 60 to 65% whiteness index and in the recycled yam will have remaining yellow (30%), blue (10%) and red (10%) resulting in scoured white with partial colour of recycled yarn.
It is very difficult to achieve solid dyeing while dyeing with this scoured / partially stripped base leading to uneven colour i.e. two different colours in the yarn portion. Solid even dyeing is not possible.
Conventional process sequence for stripping of reactive dyed goods:
1. Treat the reactive dyed fabric with strong wetting cum dispersing agent 1.0 gpl (cationic) at 95 degree Celsius for 10 minutes and drain.
2. Treat with 4-9 gpl hydros and 4-7 gpl of caustic soda at pH 11.0 - 11.5 at 80 degree Celsius for 30 minutes and drain.
3. Hot wash at 90 degree Celsius for 10 minutes with soaping cum dispersing agent. 4. Conventional half bleaching using 0.5 gpl wetting cum scouring agent, 2.5% caustic soda and 3.0 gpl hydrogen peroxide at 95 degree Celsius for 30 minutes followed by hot washing at 80 degree Celsius and neutralization and residual peroxide killer. Demerits:
1. 100 % stripping is not possible.
2/90 - 95% stripping in the case of red and blue and 80 % yellow.
3. 15-20% Strength loss of stripped fabric compared to dyed fabric before stripping. Comparison between conventional scouring vs innovative stripping:
RFD fabric WI
Yarn strength comparison - Ref - Sitra report 100% Virgin cotton - 1. Count 12s. (6 to 20 s)
RCD / virgin cotton (30/70%) Results:
New innovative process has been established for producing terry fabric has yarn with a blend of recycled dyed cotton / virgin cotton blend with solid even dyeing.
This solid dyeing is achieved by our innovative unique process where it is possible strip the
Figure imgf000014_0001
colour from the reactive dyed goods by non-hazardous chemical without affecting the strength / quality performances.
Figure imgf000015_0001
Figure imgf000016_0001
Advantages of the present invention:
Environmental pollution: Low as the waste water will have Non Hazardous organic components which are easily biodegradable.
Degradability of Stripping component: 100 % Biodegradable as this composition has GOTS approved organic components. Colour removing efficiency: 90 -95 %. (Yellow 90 % - 95 %) and other components like Red & Blue will be 95 -100 %.
Fabric Strength Loss: No tensile strength loss for the processed fabric.
Non hazardous chemicals:
1. Wetting agent - Organic - GOTS approved 2. Dispersing agent - Organic - GOTS approved
3. Stripping Agent - Organic - GOTS approved 2 Propionic acid Homo polymer - Non hazardous Stripping agent
2 Propionic acid Homopolymer is a stripping agent for cotton fabric dyed with reactive dye. It gives excellent stripping of dyes as compared against conventional method of stripping using caustic and hydrose. 2 Propionic acid Homopolymer will prevent fabric damage, which is generally observed when stripping is done by conventional method using caustic and hydrose.
KEYFEATURES & BENEFITS
Key features Benefits
Strips reactive dyes Fabric can be redyed
Economical Saves time, energy
GENERAL CHARACTERISTICS
Physical appearance: White to off-white granules
Ionic nature: Nonionic pHofl%solution: 11+/-2
Miscibility: Soluble with water
Compatibility: Compatible with anionic, cationic and Nonionic products Stability: Stable to dilute acids and dilute alkalies
APPLICATION
Step wise procedure to achieve best stripping
□ Treat with 0.3-0.5% Finocon DETR New at 95deg.C for 10 mins and Drain
□ Cold wash for 10 mins, Drain
□ Adjust batch pH to 4.0-4.5, add 3.0-5.0%, 2 Propionic acid Homopolymer raise temperature to 95deg.C for 20-30 mins, Drain
□ Hot wash at 80 deg.C for 10 mins, Drain
□ Cold wash and drain Note: If the dyed fabric is treated with dye fixing agent, then the process sequence will be as follows:
□ Treat with 0.3-0.5% Finocon DETR New at 95deg.C for 10 mins and Drain
□ Adjust bath pH4.0-5.0, Add 1-2% Finocon WS Powder at 85 deg.C for 15 mins, Drain
□ Cold wash for 10 mins and Drain
□ Adjust bath pH 4.0-4.5, Add 3-5%2 Propionic acid Homopolymer and raise temperature to 95deg.C for 20-30 mins and Drain
□ Hot wash at 80deg.C for lOmins and drain
□ Cold wash for 10 mins and drain
Hemitol SRW
Non foaming Wetting, Scouring and detergent, designed for the wetting, scouring and bleaching operation of 100 % cotton knits, in high turbulence equipments like jet and softflow dyeing machines. Features
□ Good detergency and emulsifying power, so effectively removes oily and greasy impurities as well as sizing and soil particles.
□ Since it is Low foaming it enhance high stability of product and application liquors. No risk of separation in machines with vigorous liquor circulation.
□ Good resistance to oxidative and reductive bleaching agents, alkalis and acids. Hence it can be used for Acid / Alkaline demineralization and discontinuous bleaching with Hydrogen Peroxide,
□ Very good compatibility with enzymes so, it can be used for Enzymatic Desizing.
□ Free from APEO’s, Phosphates and Sulphates
PROPERTIES
1. Physical form: Colourless liquid
2. Chemical nature Blend of Alkoxalate in aqueous medium
3. Ionic nature: Non ionic
4. pH of 1% solution: About 7
5 Specific gravity at 20 °C: 1.0 g/cm3
6 Stability to alkali: 20g/l NaOH 100 %
APPLICATION
Hemitol SRW can be added undiluted to the application baths. Feed baths should be stirred after prolonged standing.
Discontinuous Peroxide Bleach
Machine: Softflow or Jet Dyeing Machine
Material: 100 % Cotton Knits
L.Ratio: 1: 8 to 1: 5
Suggested Recipe
0.5 to 1.0 gpl Hemitol SRW
0.5 to 1 gpl Cresmer ECS/ECS cons
2.5 to 3 gpl NaOH 100%
0.2 to 0.4 gpl Perostabe GI 2 to 3 gpl H2 02 50 %
Temperature: 95- 98°C Reaction time: 45 - 60 min
HT Bleach can also be done using the above recipe at 110°C for 30 min. After bleaching one Hot wash at 90°C and cold wash with neutralizing using Acetic Acid should be given. To ensure a trouble-free subsequent dyeing we strong recommend an after treatment with Sarakol PDR 9 Soap cum dispersing agent)
Demineralization 0 5 - 1 g/1 Hemitol SRW 0.5 - 2 g/1 Mi quest DM ML ratio: 1: 5 to 1: 10 Temperature: 55 to 60 °C Time: 30 min at pH about 2.0 to 3.0 For Full White Bleach 3 - 4 g/1 NaOH 100 %
0 5 - 1 g/1 Hemitol SRW 0.2 - .5 g/1 Perostabe GI 8 - 10 0.8 - lg/1 %H202 50 %
(owm) FWA Liquor ratio: 4 : 1 - 20 : 1 Temperature: 90 - 98 °C Reaction time: 60 to 90min
Followed by hot wash cold wash and softening with Catamine NYLK or Catamine SKN
Storage, packing& Safety
Store in a cool dry place and replace the lid tightly after every use. Self Life period: 12 months from the date of manufacture, if stored properly in a un tampered pack. The usual hygiene and safety rules for handling chemicals should be observed in storage, handling and use. The product must not be swallowed. For further information on ecology and toxicology, see relevant Safety Data Sheet.
SARAKOL-PDR Product Information
Sarakol-PDR is a concentrated polymeric compound which can be readily dissolved to obtain stable solution. Sarakol-PDR is recommended in reactive dyeing by exhaust method. In case of reactive dyes which are having low solubility in presence of salt and alkali and when liquor ratio is low there could be precipitation of dyes during the dyeing, leading to poor colour yield as well as precipitation of dyes on substrate and machine. Addition of Sarakol-PDR overcomes this problem due to its excellent dispersing action. Calcium and Magnessium impurities in the dyebath could also lead to precipitation of dyes as well as poor washing off of hydrolysed dyes at the end of dyeing. Due to its chelating action, Sarakol-PDR prevents such precipitation and also helps in easy removal of hydrolysed reactive dyes at the end of dyeing operation. Sarakol-PDR is also recommended as a washing off agent for reactive dyes in batch operation as well as in continuous operation.
Key Features & Benefits
Figure imgf000020_0001
General Characteristics
Physical appearance: White powder Ionic Nature: Anionic pH of 1% solution: 9 +/- 1 Miscibility: Soluble in water after soaking Compatibility: Compatible with nonionic and anionic products Stability: Stable to dilute acids & dilute alkalies
Application
1) Exhaust Dyeing of reactives 0.2-0.3% Sarakol-PDR is added in the bath before addition of dyestuffs or chemicals. Quantity of Sarakol-PDR would depend upon liquor ratio, quality of process water, quality of salt and efficiency of scouring operation as well as concentration and solubility of the dyestuffs used in the recipe.
2) Washing off of Reactive Dyes by Batch Operation 0.15-0.3 g/1 Sarakol-PDR
0.1-0.2 g/1 Kalium-NNS Cone (optional) pH adjusted to 7, Residual salt concentration should be less than 2 g/1 before soaping. Carry out soaping at 85-95 deg.C for 10-30 min., hot wash, cold wash, neutralise. Repeat soaping in fresh bath for dark and problematic shades. Carry out fixation for dark and problematic shades. 3) Soaping of reactives on continuous soaper 0.3-1 g/1 Sarakol-PDR at 95-98 deg.C, pH 7-7.5
4) Development of vat dyes 0.3-0.5 g/1 Sarakol-PDR in development bath with caustic & hydrose on continuous range.
Instructions For Dilution Take 20-30 parts of Sarakol-PDR. Add slowly to 80-70 parts DM water, maintained at 60 deg.C, pH 7-7.5, with continuous stirring using Turbo stirrer at 2000-3000 rpm. Temperature of 62 +/- 2 deg.C is maintained till dilution is completed. Stir for 30-60 min. for homogenisation. Cool and filter through nylon filter cloth of 200-250 mesh size. Discard residues if any. Maintain pH at 7- 7.5.
Precautions
Storage: Store in cool, ventilated shed away from heat and direct sunlight. Storage temperature should not exceed 35 deg C. Close lids firmly to avoid contact with air and moisture.
Shelf Life: 6 months from the date of manufacturing, if stored under controlled conditions.

Claims

I CLAIM:
1. A reactive dye stripping composition for dyed / dyed recycled cotton yarns, comprising of:
Wetting agent - 0.3 to 0.5 gpl;
Dispersing agent - 0.5 gpl; and stripping agent, wherein the composition essentially consists of stripping agent 2-propenoic acid, homopolymer based polymer in a weight ratio of 3.0% to 7.0% v/v. on weight of fabric.
2. A reactive dye stripping composition for reactive dyed / recycled cotton yams, comprising of: wetting agent — 0.5 — 1.0 g/1 ; dispersing agent - 0.5 - 1.0 g/1; and stripping agent - 4-6 g/1, wherein the stripping agent is 2-propionic acid homopolymer.
3. A reactive dye stripping composition for dyed fabric / yarn / recycled cotton yarns as claimed in claim 1 and 2, wherein the wetting agent is like a blend of alkoxalate in aqueous medium - non-ionic product.
4. The reactive dye stripping composition for dyed fabric / yarn / recycled cotton yams as claimed in claim 1 and 2, wherein the dispersing agent is like concentrated polymeric compound.
5. The dye stripping composition dyed fabric / yam / recycled cotton yams with virgin cotton blends as claimed in claims 1 and 2, wherein the pH of the composition is 4.0 to 5.0.
6. A method for stripping reactive dye from dyed fabric / yarn / recycled dyed cotton yams,/ virgin blends comprising of the steps: desizing of the dyed recycled yam for twice at 60 degree Celsius for 30 minutes; hot wash at 80 degree Celsius for a period of 10 minutes with 1 gpl dispersing agent followed by cold wash for 10 minutes; colour stripping process characterized in that comprising the steps of: treating with 0.3 to 0.5 % detergent cum dispersing agent at 95 degree Celsius for 10 minutes; adjust the pH to 4 to 4.5; add 3 to 5.0 % of 2-Propenoic acid homopolymer, raise the temperature to 95 degree Celsius for 20 - 30 minutes and drain; hot wash at 80 degree Celsius with detergent cum dispersing agent for 10 minutes; scouring / half bleaching at 95 degree Celsius for 30 minutes; hot wash at 80 degree for 15 minutes with 0.5 gpl detergent cum dispersing agent; hot wash at 70 degree Celsius for 10 minutes; neutralization with glacial acetic acid 0.3 gpl for 15 minutes; and followed by treating with Peroxide killer 0.05 gpl and bipolishing 0.3 gpl for 20 minutes.
7. The method for stripping reactive dye from fabric / yarn /recycled cotton / virgin blend yams as claimed in claim 6, wherein the scouring / half bleaching agent comprises of Caustic soda flakes - 3.0 gpl; Hydrogen peroxide - 3.0 gpl; Wetting agent - 0.5 gpl; and Organic based stabilizer - 0.3 gpl.
8. The method for stripping reactive dye from dyed fabric / yam /recycled cotton yarns with virgin cotton blends as claimed in claim 6, wherein fabric comprises recycled dyed cotton / virgin cotton blend yarn in a blend ratio of 50 / 50 % to 10 / 90 %.
9. A method for stripping reactive dye from recycled cotton yarns, comprising of the steps: adding water 1:6; then adding the fabric; add chemicals: wetting agent 0.5 - 1.- g/1, dispersing agent - 0.5 - 1.0 g/1, and stripping agent 4-6 g/1; adjust the pH 4.0 - 5.0; temperature raise up to 95 degree Celsius; hold 20 - 30 mins; hot wash at 80 degree Celsius ran 10 minutes; hot wash at 70 degree Celsius ran 10 minutes; and cold wash at 40 degree Celsius ran 10 minutes.
10. The method for stripping reactive dye from dyed fabric / yarn /recycled cotton dyed yams with virgin cotton blends, wherein the process parameters includes pH - 4.0 - 5.0, temperature - 95 degree Celsius, time: 20 - 30 minutes, M:LR- 1:6.
PCT/IN2022/050221 2021-03-11 2022-03-10 Colour stripping composition for dyed cotton textiles and method thereof WO2022190131A1 (en)

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Citations (5)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
EP0422683A1 (en) * 1989-10-13 1991-04-17 Nihon Surfactant Kogyo K.K. Washing-off agent composition for dyed cellulose fiber articles
CN102454126B (en) * 2010-10-18 2014-04-23 南通斯恩特纺织科技有限公司 Efficient environment-friendly neutral soaping agent for reactive dye and preparation method for efficient environment-friendly neutral soaping agent
CN104420371A (en) * 2013-09-09 2015-03-18 青岛三秀新科技复合面料有限公司 Color stripping method of cotton dyed by reactive dye and wool and silk dyed by acid dye
US9670614B2 (en) * 2011-09-23 2017-06-06 Novozymes A/S Color modification of textile
WO2021013842A1 (en) * 2019-07-24 2021-01-28 Smart Coloring Gmbh Method for reversible and selective dyeing of a synthetic polar-polymer material; dyed synthetic polar-polymer material and article thereof

Patent Citations (5)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
EP0422683A1 (en) * 1989-10-13 1991-04-17 Nihon Surfactant Kogyo K.K. Washing-off agent composition for dyed cellulose fiber articles
CN102454126B (en) * 2010-10-18 2014-04-23 南通斯恩特纺织科技有限公司 Efficient environment-friendly neutral soaping agent for reactive dye and preparation method for efficient environment-friendly neutral soaping agent
US9670614B2 (en) * 2011-09-23 2017-06-06 Novozymes A/S Color modification of textile
CN104420371A (en) * 2013-09-09 2015-03-18 青岛三秀新科技复合面料有限公司 Color stripping method of cotton dyed by reactive dye and wool and silk dyed by acid dye
WO2021013842A1 (en) * 2019-07-24 2021-01-28 Smart Coloring Gmbh Method for reversible and selective dyeing of a synthetic polar-polymer material; dyed synthetic polar-polymer material and article thereof

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