Factors Affecting the Dyeing of Cotton

Introduction:
Nowadays cotton dyeing has become the main subject for discussion. Lot of expansion on cotton dyeing are coming up like cotton fiber dyeing units (for mélange shades and polyester /cotton blended solid shades). Yarn dyeing units (for terry towel, socks, shirting and suitings) and fabric dyeing units (for woven and knitted fabrics). It can be classified further to continuous (pad-dry-pad steam) and cold silicate pad batch dyeing process.

The competition is so stiff that the units are trying their best to provide high quality material to survive in the market.

Cotton dyeing is difficult as compared to synthetic dyeing. As cotton is a natural fibre lot of variables come into play during dyeing. The cotton technicians should be qualified to understand the problems and convinced the top management. Results will come gradually.

Factors Affecting the Dyeing of Cotton
Fig: Cotton dyeing

Factors Affecting the Dyeing of Cotton:
The principle of cotton dyeing is to exhaust as much dye as possible onto the fibres. This exhaustion of dye is affected by the following factors.

  1. Dissolving of dyes.
  2. Water quality.
  3. Substantivity of the dye.
  4. Temperature of the dyebath.
  5. Kind and amount of alkali.
  6. Liquor ratio.
  7. Amount of inorganic neutral salt.
  8. Effect of metallic ions in water.

The following factors are described as below:

1. Dissolving of Dyes:
The dyes are best dissolved by pasting with cold water and pouring hot water (50 –55 deg c) with high speed stirring. To avoid losses and colour yield through hydrolysis following precautions are necessary.

  1. The pH of water should be slightly acid to neutral. if alkaline make neutral by addition of acetic acid.
  2. It is advisable to use soft or softened water. if water is hard, then 1 gpl sodium hexa metaphosphate may be added.
  3. Prepare the dye solution just prior to use.
  4. Do not attempt to dissolve dyeing assistants or auxiliaries with the dyes.
  5. Dye solutions must be sieved on introduction to the dyeing machine addition tank.

2. Water Quality:
Reactive dyes are very sensitive to water conditions. The dyeing and washing off should be carried out with soft water. Small amounts of calcium and magnesium can affect migration and diffusion properties of reactive dyes, cause restraining or even precipitation resulting in following defects.

  1. Reduced yields.
  2. Unlevelness.
  3. Poor reproducibility.
  4. Reduced fastness.

The maximum recommended level for dyehouse water is.

  • Total hardness: 50 – 55 ppm.
  • pH: 7.0 +/_ 0.5.
  • Copper: 0.05 mg/l.
  • Iron: 0.05 mg /l.
  • Chloride ions: 300 mg/l.

3. Substantivity of the Dye:
Reactive dyes are widely applied to cotton. The dyeing of cotton using reactive dyes are carried out in the presence of large amount of water and it is necessary to exhaust as much dyes as possible from the dyebath onto the textile fibres before the reaction between the dyes and fibre starts.

For this purpose, it is desirable to apply dyes with a high degree of exhaustion (substantivity). However in the opposite case where the substantivity is too high, then the migration property of the dyes decreases and the possibility of unlevel dyeing increases. So proper substantivity between the dyes and fibres becomes necessary.

It is generally well known that the substantivity of reactive dyes for cotton is affected by dye structure, dye concentration, concentration of inorganic salts, dyebath temperature and pH value. Reactive dyes with a plane molecular structure have a high substantivity. Reactive dyes for cotton should have the following performances.

  1. Proper degree of exhaustion (substantivity), (degree of exhaustion of about 50 % or thereabouts with an addition of 50 gpl glauber salt anhydrous).
  2. High degree of dye fixation.
  3. Easy removal of infixed dyes (good washing off property).
  4. Good fastness properties.

The above properties from (a) to (d) are mutually related to each other.

4. Temperature of the Dyebath:
There are three classes of reactive dyes.

  • Bifunctional type.
  • Vinyl sulphone based reactive dyes.
  • Cyanuric chloride based reactive dyes
    • High exhaust (HE)
    • Hot brand
    • Cold brand.

The most common reactive dyes used in textile dyeing of cotton is Bifunctional type dyes which are a group of mixed bifunctional reactive dyes having sulphato ethyl sulfone group linked to the chromophore through monochloro triazine group as a bridge link. One of the great advantages obtained by combining the two different types of reactive groups, sulfatoethylsulfone and monochlorotriazine is that in exhaust dyeing there is little change in colour yield even if there is some change in dyeing temperature within temperature range from 50 deg c to 80 deg c., because the reactivities of these two reactive groups compensate each other at this temperature range. So dyeing at 60 deg c at which the levelness and consumption of energy are balanced, is considered to be most desirable.

5. Kind and Amount of Alkali:
Soda ash alone is always the preferred alkali, but in order to reduce the amount of handling needed a mixture of soda ash and caustic soda or a formulated liquid alkali may be used for fixation of the dyes.

Care must be taken with industrial grades that may contain a certain amount of sodium bicarbonate. This reduces the pH during fixation phase. As caustic soda is a strong alkali, it easily causes fluctuation in shade by weighing error, so that the single use of it is not recommended. But if used with soda ash, buffer effect is created to enable its combined application without any practical problems. Particularly, in the combined use of soda ash and caustic soda; soda ash should be added first and then caustic soda. Or the aqueous solutions of the two alkalis should be mixed together before hand and then the mixture should be added to the dyebath. Alkali is necessary for the ionization of cotton and the activation of reactive dyes. A suitable pH of the dyebath in exhaust dyeing is about 11 – 12, though it depends also on dyeing temperature. Soda ash (sodium carbonate) also turns into sodium bicarbonate through the action of acid gas in the atmosphere. Consequently soda ash left over a long period may contain from 10 to 20 % of sodium bicarbonate.

6. Liquor Ratio:
In dyehouse practice, there are sometimes differences in liquor ratio between dyeing equipments of laboratory and production or variations from batch to batch, so that the liquor ratio dependence can be a problem concerning the reproducibility of dyeing.

Reactive dyes are generally low in substantivity so that they are easily affected by liquor ratio.

To obtain dyeings with high efficiency, it is important to carry out dyeing at the shortest possible liquor ratio. Liquor ratio must therefore be determined with careful attention to balance with levelness.

7. Amount of Inorganic Neutral Salt:
In order to increase the dye fixation in cotton exhaust dyeing, it is important to exhaust as much dye as possible onto the fibers. The addition of inorganic neutral salt, in particular serves to raise the dye exhaustion to a large extent. However, in deep dyeing or in short –liquor dyeing, an addition of large amount of inorganic neutral salt than required lowers the solubility of dyes in the dyebath, which leads to an occurrence of a phenomenon that the degree of fixation is not increased so much. Normally the salts used in textile industries are Tata salt, Vacuum salt, Birla salt, Cookwell salt and Glauber salt.

8. Effect of Metallic Ions in Water:
Generally, many reactive dyes are of low molecular weight and coloring matters are formed based on the organic balance between a chromophore and an auxochrome maintained in the molecule. When this balance collapses, it is not possible to obtain the desired shades.

Generally, metallic ions in water, particularly iron and copper ions have a considerable effect on shade. When the water contains large amounts of calcium or magnesium ions, almost no change in shade occurs. However, these ions have a strong adsorption capacity onto fibers and are thus difficult to remove even by after treatment such as soaping, and they remain on fibers and cause the so – called phenomenon of white powder dusting when the dyed materials are dried and finished. Consequently, sufficient care should be taken to metallic ions in the water. To avoid fluctuations in shade from the influence of metallic ions in dyebath, polyphosphate is generally used as a sequestering agent in cotton exhaust dyeing. When metal complex reactive dyes are used, attention should be given to the use of a strong sequestering agent such as EDTA.

All the above points play a vital role in cotton dyeing. Especially the new units should bear the above points and do the needful.

Exploring the Loom: A Journey Through Diverse Weaving Shuttles

Abstract:
weaving shuttle is a Weaving Loom accessory that is used to pass the weft thread (horizontal thread) through the warp threads (vertical threads) of a Loom. The introduction of the Fly Shuttles during the Industrial Revolution changed the course of the Textile Industry to a greater extent. In this article, I have focused on origin and historical development of Shuttles with a brief explanation of different types of Shuttles along with their functions & uses. Also covered the limitations & alternates of Shuttles in the modern Weaving Industry.

The different types of weaving shuttles.
Fig: The different types of weaving shuttles. Photo by Thread Collective

Origin & Evolution of Weaving Shuttles:
Before the invention of flying Shuttles, weaving was a labor-oriented & time-consuming process. A great number of manual labour was needed to operate atypical frame Loom where the weft thread passed manually through the shed of the warp threads. This process has to be repeated during each pick insertion which eventually limits the speed & efficiency of the weaving process.

During the Industrial Revolution, the fly shuttle was invented in 1733 by an English inventor named John Key. He developed a wheeled shuttle that was later known as a flying shuttle. Flying shuttle changed the course of Conventional Weaving by introducing several key developments:

  • Improved Weaving Efficiency
  • Reduced labour
  • Saved time that initiated the Industrialization of weaving.
John Key and Handloom Source Getty Image

In later developments, installing guards reduced the fast-moving shuttle that injured the weaver’s hands. Flying Shuttles wide spread commercially around the 1950s.

Materials and Functions of Shuttles:
Various types of materials are used to make Weaving Shuttles including wood, metal, plastic and even cardboard. Shuttles can be in different shapes and sizes depending on the end use and types of looms.

Weaving Shuttles is mainly used in woven fabric production. The shuttle holds a bobbin of weft thread. When the weavers release the shuttles by pulling a cord using the foot pedal (Hand Loom) or starting the machine (Power Loom), the shuttle passes through the warp shed and reaches the other side of the loom. Then the weft thread carried by the shuttle finally beat up into the cloth fell by using loom’s Reed to create one pick of woven fabric. Using fly Shuttles is advantageous in producing wider fabric because it overcomes the limitations imposed by the weavers’ arm span.

Using the Shuttle on the Loom
Fig: Using the Shuttle on the Loom

Shuttle Spectrum: Types and Varieties:

1.  Stick Shuttle:
Stick Shuttles are generally used on table Looms (including rigid heddle looms) with an arrow shed. The shuttle doesn’t glide a cross the warp on a shuttle race but instead passes from right to left hand and back again. Yarn is wound on a flat stick shuttle with a figure eight using the armor notches from the top right to the top left.

Stick Shuttle
Fig: Stick Shuttle

2.  Belt or Band Shuttle:
It’s generally used on an inkle or band Loom. Generally, it has a knife edge on one side designed for packing in the weft and a recessed centre through to carry more weft. Despite its small size (6-10inches),it can hold a good amount of weft yarn.

Belt or Band Shuttle
Fig: Belt or Band Shuttle

3.  Netting Shuttle:
It’s used mainly in making and repairing fishing nets. But nowadays, weavers use it in hand manipulation techniques such as Spanish Meda/Ions or Brook’s Bouquet design. It can be used effectively for adding short lengths of the weft of a special colour or designer yarn.

Netting Shuttle
Fig: Netting Shuttle

4.  Rag Shuttle:
It’s generally used in counter balance and counterparts Loom where large warp shed can be found. It’s used to hold a flat strip of Fabric for rag rugs or other similar projects. The rag shuttle keeps the rag strip flat by winding around and around.

Rag Shuttle
Fig: Rag Shuttle

5. Boat Shuttle:
It looks a bit like a boat because of its shape and has a rod fora bobbin or a quill full of yarn. The bobbin spins around as the yarn comes off. Based on the size, it can used for both thick or thin woven fabric making.

Boat Shuttle
Fig: Boat Shuttle

6. End Feed Shuttle:
It looks like a boat shuttle but it holds bobbins. Rather yarn is wound around a pirn and is pulled off the end and through a hole in the shuttle. The end feed shuttle can maintain even tension and is best suited for weaving the edges.

End Feed Shuttle
Fig: End Feed Shuttle

7.  Fly Shuttle:
It’s a Specialized type of end-feed shuttle that connects to the loom and automatically throws the shuttle back and forth by using different under and over-picking mechanisms. It’s usually heavier and has sharp metal ends on both sides.

Fly Shuttle
Fig: Fly Shuttle

8. Skii Shuttle:
It is designed in a way that the yarn is wrapped horizontally around the top of the skii. It can hold medium or heavy yarns. Its unique shape lets it slide through the shed while dragging on the warp yarns.

Skii Shuttle
Fig: Skii Shuttle

Ski shuttle, The middle section helps to hold up the upper ends of a narrow shed.

Draw backs of Shuttle-Based Looms:
Despite being economical and easy to use, shuttle Looms have some major drawbacks that force the modernization of the Weaving Industry.

  • High noise during weaving
  • Warp breaks in crease for the shuttle
  • Shuttle flies from the shed and can cause accident
  • Production rate is lower than shuttle less loom
  • Losing the value of Fabric due to shuttle movement

Modern Alternatives of Weaving Shuttles:
In the modern weaving industry, shuttle less Loom has been introduced. In the shuttle less Loom, weft insertion is done by various devices such as rapier, air jet, water spray, projectile, multi-spindle mouth etc.

Shuttle less Loom can be categorized as follows:

Rapier loom and Projectile loom
Fig: Rapier Loom and Projectile Loom

Conclusion:
The invention of the weaving Shuttles during the Industrial Revolution helped in the formation of the weaving Industry from cottage-based weaving. Shuttles Increased weaving efficiency and reduced labour cost. Despite having such benefits of usage and lower price, shuttle-based Loom has some major drawbacks that open the path of modern shuttle less Loom. Still, the shuttle is used by the rural people and different tribes for the production of their traditional woven cloth by using a hand Loom.

Mastering the Art of Apparel Distribution: Embracing Modern Practices

Apparel distribution is a critical aspect of the fashion industry, ensuring that clothing reaches the hands of consumers seamlessly and efficiently. As the fashion landscape continues to evolve, embracing modern practices in apparel distribution has become more essential than ever. Gone are the days of relying solely on traditional distribution models; today’s market requires an agile and tech-savvy approach to meet customer expectations and gain a competitive edge.

This article will explore the art of mastering apparel distribution by embracing modern practices. We will delve into the significance of modern practices in today’s market and how they play a crucial role in shaping the success of fashion businesses. From e-commerce and technology integration to collaborative partnerships and data analytics, we will examine the emerging trends revolutionizing the distribution landscape. By understanding and implementing these modern practices, fashion businesses can optimize their distribution processes, enhance customer experiences, and ultimately thrive in a fast-paced and ever-changing industry. So, let us embark on this journey of exploring the art of apparel distribution and discovering the power of embracing modern practices.

Historical Context of Apparel Distribution
For decades, the apparel distribution landscape relied heavily on traditional methods that involved multiple intermediaries and brick-and-mortar retail stores. This approach often posed challenges such as high overhead costs, limited market reach, and slow response to changing trends. The traditional distribution model required manufacturers to produce and ship clothing in bulk to retail stores, where customers would physically browse and purchase items. While this model served its purpose in its time, it lacked the agility and efficiency essential in the fast-paced fashion industry.

Apparel Distribution

However, there has been a remarkable shift towards modern distribution practices in the apparel industry in recent years. This shift has been driven primarily by the rise of e-commerce and technological advancements. The emergence of online shopping platforms and the increasing prevalence of mobile devices have allowed consumers to access various clothing options from the comfort of their homes. Apparel brands have recognized the potential of selling online, bypassing traditional retail channels to reach a wider audience. Moreover, technology has paved the way for various advancements in supply chain management, including real-time inventory tracking, automated apparel fulfillment, and sophisticated data analytics. These modern practices have not only streamlined the distribution process but also enabled brands to respond swiftly to market demands and offer personalized experiences to their customers. Adopting modern distribution practices marks a significant turning point in the apparel industry, empowering businesses to enhance their operations, improve customer satisfaction, and adapt to the ever-evolving market needs.

Understanding Modern Consumers
The modern fashion consumer has undergone a significant transformation compared to the consumer of past decades. With the widespread availability of technology, digital behavior, and online shopping trends have become an integral part of consumer behavior. Shopping online for clothing has become increasingly popular due to its convenience and accessibility. Today’s consumers desire fast turnaround times, with the demand for fast fashion becoming more urgent. They expect their favorite brands to release new collections quickly, often within weeks of a fashion show or even sooner.

In addition to quick turnaround times, consumers have rising expectations for sustainable and ethical sourcing practices from their favorite apparel brands. The modern consumer prioritizes environmentally conscious and socially responsible practices, holding brands accountable for the impact of their operations on the planet and society. Successful apparel businesses that have embraced modern practices in distribution have adapted to this new consumer landscape by swiftly responding to market trends, implementing sustainable practices, and building transparency into their supply chains.

The Role Of Technology in Modern Distribution
In today’s rapidly evolving apparel distribution landscape, technology plays a pivotal role in shaping the success of fashion businesses. From reaching a global audience to streamlining operations, modern technologies bring numerous benefits when integrated into the distribution process.

1. E-commerce Platforms:
E-commerce platforms have revolutionized the way apparel businesses reach and engage with customers. These online platforms provide a global reach, allowing brands to expand their customer base beyond geographical boundaries. By embracing e-commerce, fashion businesses can break free from the limitations of brick-and-mortar stores and cater to the ever-growing demand for online shopping. Furthermore, e-commerce platforms provide valuable tools for managing inventory and sales analytics. Real-time inventory tracking helps businesses ensure that the right products are available to customers, reducing stockouts and improving order fulfillment. Sales analytics provide insights into customer preferences, allowing businesses to make data-driven decisions and optimize their product offerings.

2. Supply Chain Management Software:
Efficient supply chain management is crucial for successful apparel distribution. Supply chain management software has emerged as a game-changer, enabling businesses to enhance efficiency and accuracy in their distribution processes. These software solutions streamline various aspects of the supply chain, from procurement and production to warehousing and logistics. Supply chain management software reduces errors, improves productivity, and allows businesses to respond swiftly to changing market demands by automating manual tasks and streamlining workflows. One of the key advantages of these software solutions is the integration of predictive analytics for demand forecasting. By analyzing historical data and market trends, businesses can accurately forecast future demand, optimizing inventory levels and minimizing the risk of overstocking or stockouts.

3. RFID and Barcode Technology:
In the realm of apparel distribution, efficiency and accuracy are paramount. RFID (Radio Frequency Identification) and barcode technology have emerged as transformative tools for streamlining warehouse operations and improving inventory tracking. RFID tags and barcode labels allow for seamless identification and tracking of individual products throughout the supply chain. These technologies enable businesses to automate inventory management, reducing human errors and improving overall operational efficiency. With real-time visibility into inventory levels and locations, businesses can minimize stock discrepancies, enhance order accuracy, and optimize warehouse space utilization. RFID and barcode technology bring greater transparency to the distribution process, enabling businesses to gain control over their inventory and reduce costly errors.

RFID technology

Sustainable and Ethical Distribution Practices
The fashion industry has recently faced increased scrutiny over its impact on the environment and society. Consumers are becoming more aware of their purchasing decisions’ social and environmental implications, leading to a growing demand for eco-friendly apparel and ethical sourcing and distribution practices. Embracing sustainability and ethical practices in apparel distribution provides numerous benefits for fashion businesses and the planet.

1. Eco-friendly Packaging:
Packaging is an essential aspect of apparel distribution, and using eco-friendly materials can significantly impact a brand’s environmental footprint. Sustainable packaging can take many forms, such as recycled or biodegradable materials, reusable containers, and creative alternatives to traditional packaging. Using eco-friendly packaging materials can also positively impact a brand’s image, as it demonstrates a commitment to sustainability and environmental consciousness.

2. Sustainable Transportation:
Transportation is another significant contributor to the environmental impact of apparel distribution. The carbon footprint associated with shipping products worldwide is enormous, making it crucial for fashion businesses to look for ways to reduce their environmental impact. Sustainable transportation options include using electric vehicles, alternative fuels, and efficient route planning. Switching to sustainable transportation can significantly reduce a brand’s carbon footprint and improve its environmental credentials.

3. Ethical Labor Practices:
Fashion businesses must ensure ethical sourcing and distribution practices to build customer loyalty and avoid negative publicity. Ethical labor practices ensure that workers in apparel production are treated fairly, receive a living wage, and work in safe conditions. This benefits workers and helps build a trusted and reliable supply chain. Fashion businesses can build brand loyalty and a positive reputation by ensuring ethical production practices.

The Power of Direct-to-Consumer (DTC) Models
The direct-to-consumer (DTC) model has emerged as a powerful and transformative strategy for fashion businesses. Unlike traditional distribution channels that involve intermediaries like wholesalers and retailers, the DTC model allows brands to sell their products directly to consumers. This approach offers numerous advantages, including greater control over the customer experience, increased profit margins, and valuable insights into consumer behavior. By eliminating intermediaries, brands can directly interact with customers, providing personalized shopping experiences and strengthening brand loyalty. Additionally, the DTC model allows businesses to gather valuable customer data and tailor their products and marketing strategies to meet specific customer needs and preferences.

Conclusion
Mastering the art of apparel distribution requires fashion businesses to embrace modern practices that respond to the rapidly evolving market trends and consumer demands. From sustainable and ethical distribution practices to leveraging data analytics and embracing direct-to-consumer models, our analysis highlights various strategies that can help businesses succeed in the apparel distribution landscape. With an emphasis on building brand loyalty, reducing costs, and improving operational efficiency, fashion businesses must invest in modern distribution strategies that align with customer preferences and market trends. As the industry continues to evolve, the call to action for fashion brands is to embrace these practices and build resilient and adaptive supply chains to ensure their continued success.