Improving Warp Yarn at the Size Box

Physical properties of warp yarn are improved by incorporating oligomer resin into the yarn interior at the size box. These improvements yield benefits at each step of the fabric formation process from size box to the woven greige fabric. Warp sizing technology has been in a period of stagnation following the introduction of synthetic polymers into size formulations nearly 60 years ago. As noted in the following Warp Sizing: knitting fair us A Brief History, abrasion-resistant surface barriers may have reached optimum performance in sizing.

Warp Sizing: A Brief History

Around 1740, increases in woven fabric production were anticipated with the development of the mechanical loom. Optimism was quickly tempered by severe loom abrasion of machine direction yarn. Loom abrasion of yarn prevented any realistic production expectations to be achieved. This problem inspired the adoption of a concept from the coatings industry and a protective surface barrier was applied to machine direction yarn. Starch provided an economical and effective barrier film which could be easily removed from loom state fabric after weaving. Machines were soon developed to apply this barrier coating to yarn.

Following the introduction of synthetic fiber/cotton blends, poor adhesion of starch size formulations forced adoption of high molecular weight, and higher cost, synthetic polymers into warp size formulations. This was the last major change in warp sizing. The barrier concept has been refined to a point where it is now considered to be “the best that we can do”. Synthetic polymer/starch blends are now the primary choice in spun yarn size formulations and warp sizing has now become an outlier in our industry. Thankfully, this attitude has not reached acceptance on either side of the size box.

Consider the Warp Size Process

More is involved in applying a barrier coating to warp yarn than a simple “painting process”. The slasher requires significant capital, large manufacturing space, continual preventative maintenance, and constant personnel training. Application of abrasion barrier and lubricant to warp yarn have been the sole function of the slasher.

Improving Yarn Background

Investigation of oligomer resins was initially proposed for potential adhesion improvement of high molecular weight polymer size films to yarn. All trials were performed in operating mills with no changes to established practices. Results were very confusing. Evaluations with oligomer resins provided benefits far beyond any improvements in adhesion by the barrier film. Results did not fit into any logical interpretation which could be attributed solely to a surface barrier coating. Every step in the process from size box through greige fabric demonstrated benefits. Oligomer resin technology appeared to be adding more than improving adhesion to the size film to the most important component of the entire process.

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Proposed Mechanism

An article presented in this forum in 2019 provided a high magnification cross-section photomicrograph of 40’s Ne ring-spun cotton yarn. This cross-section photo illustrates the presence of micron size voids typical present between fibers in spun yarn. Empty spaces between fibers in spun yarns are determined by the limit of fiber cohesion and are stabilized by anionic repulsive forces on adjacent fiber surfaces.

As warp yarn enters the size formulation, water and oligomer resin are carried throughout the yarn bundle. Oligomer particles immediately are attracted to fiber surfaces and properties of the resin overwhelm any anionic character present. Elimination of repulsive forces on fiber surfaces permits a more intimate fiber arrangement within the yarn bundle. The result is a more compact substrate and the resulting increase in fiber cohesion within the yarn bundle. Increases in fiber cohesion are reflected in the physical properties of the yarn substrate.

Verifying the Proposed Mechanism

Improvements in physical properties of only the yarn itself cannot be measured directly in sized yarn. Comparisons of hard yarn with and without oligomer resin provide useful data but do not rule out the barrier film as the basis of improvement. Two alternative methods were investigated to detect yarn changes resulting from oligomer resin. Addition of oligomer resin in the final rinse of a mock dye procedure provided improvements in both tensile and elongation.

A second approach was conducted to identify potential improvement in yarn properties by spraying oligomer resin directly on fiber. The test was conducted at the USDA facility in New Orleans, Louisiana. A 540 lb bale of Pima cotton (supplied by Buhler Yarns, Jefferson, GA) was crudely sprayed with 8 lb of a 15% active dispersion. The treated cotton fiber was then processed through the USDA production unit to produce 30’s Ne ring spun yarn. No processing problems were noted throughout the entire process. After spinning, control and treated yarns were sent to Gaston Textile Technologies in Belmont, NC for evaluation.

Source: textiles school

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A decade long collaboration between Swiss textile innovator HeiQ and Spanish premium synthetic fibre manufacturer Nylstar, has resulted in a new antiviral and antimicrobial fabric, with what Nylstar calls zero pollution sustainable benefits. Meryl Skinlife Force powered by HeiQ Viroblock Permanent, is a winner at ISPO Textrends Award for the Best Product.

With the commencement of the pandemic, the two leading textile innovators pooled resources, developed over a decade long collaboration, to create a premium synthetic fibre that they say is sustainable, antimicrobial and durable. In short, the collaborators say, the optimal fusion of innovative ingredient into sustainably made materials.

A record-breaking development speed of just six months resulted in the launch of HeiQ Viroblock Permanent, a new technology under the immensely successful HeiQ Viroblock technology platform. The new technology is used exclusively on Meryl Skinlife Force, an innovative hi-tech fabric that combines the silver-ion active principle antimicrobial properties developed by HeiQ, and Nylstar’s hydrogen-based technology which allows the creation of yarns with a very strong molecular cohesion structure.

HeiQ is a company focused on textile technology innovation. For 15 years, HeiQ has helped more than 100 well-known brands improve textile functions. To support the global coronavirus fight, HeiQ timely launched the anti-viral and anti-bacterial textile processing technology HeiQ Viroblock NPJ03 (referred to as "Viroblock"). The mask test proved effective against human coronavirus. Masks treated with Viroblock greatly reduce the infectivity of human coronavirus (229E), influenza virus H1N1, H5N1, H7N9 and respiratory syncytial virus (RSV). Among them, in the test for human coronavirus, the logarithmic reduction of the viral infectivity of untreated masks was 2.90, while that of masks treated by Viroblock increased to 4.48, and the viral infectivity was reduced by more than 99.99%.

The Hydrogen molecular structure makes Meryl Skinlife Force a high-performance fabric in terms of moisture management and breathability, offering a natural stretch without elastane as well as excellent durability thanks to its continuous and high tenacity filaments, Nylstar says. Nylstar reports that the robust durability of HeiQ Viroblock Permanent is achieved thanks to the silver particles being added directly into the raw polymer of the yarn thereby keeping these properties active for the lifetime of garments, it adds. Fabric samples successfully demonstrated a very strong antimicrobial efficacy with over 99.99% reduction of both gram-positive and gram-negative bacteria after 100 washes. Antiviral test is underway.

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“With the launch of HeiQ Viroblock Permanent on this premium fabric that can be implemented in environments with high hygienic and sanitary requirements such as medical, hospitality and sports, HeiQ and Nylstar aim to make a strong social contribution to stemming the spread of the global pandemic and for post-pandemic use, delivering on our mission to improve lives of billions of people,” said Carlo Centonze, co-founder and CEO of HeiQ.

Nylstar’s zero microfiber release in combination with HeiQ Viroblock Permanent technology bring the textile industry the necessary quality and touch without polluting air and water, Nylstar explains. Meryl Skinlife Force HeiQ Viroblock Permanent hi-tech fabric is certified by STANDARD 100 Oekotex assuring the consumer that the product is free of harmful substances, and all 100% Meryl fabrics are completely and infinitely recyclable without suffering any loss of performance, for a fully sustainable and circular economy, it adds.

Meeting the most demanding antimicrobial and durability qualities for the lifetime of the garments, this premium fabric is the perfect match for discerning medical, hospitality and sports professionals who wish for durable protection not just in the time of the pandemic but well beyond into a post-pandemic future, Nylstar says.

“Meryl Skinlife Force powered by HeiQ Viroblock Permanent is fabricated to meet the most exacting requirements on performance and sustainability of consumers in today’s day and age,” said Alfonso Cirera, Executive Chairman of Nylstar.

According to Knitting fair, Viroblock uniquely combines vesicle and silver technology to inhibit the growth and retention of bacteria and viruses. The HeiQ vesicle technology targets the coronaviruses and other lipid-developed viruses to quickly kill the viruses, while the HeiQ silver technology inhibits the replication of bacteria and viruses. Viroblock can be used on various textile surfaces, including masks, air filters, medical clothes, curtains, etc. So far, scientists have identified seven human coronaviruses. 229E and Covid-19 are two of them.

Source: Knitting Industry

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Pressures in the apparel industry are complex, multidimensional, and not easy to classify. However, based on the review of experiences shared by the peers in the industry, knitting fair are classified into four categories and discussed in the paper.

Market pressure

In the apparel industry, fashions change at lightning speed, and new trends and consumer preferences emerge at the blink of an eye – today, even more than in the past. Apparel brand-owners are under pressure to formulate winning strategies to achieve a competitive price. They are in expectation to get their products from the design centre to the store faster than ever, and retailers must stock and sell those products immediately while consumer interest is at its highest – and before the next selling season begins.

Gross margins on apparel have dropped significantly in the past two years as a result of the global economic turmoil, as retailers have slashed prices to move merchandise. This has put renewed pressure on retailers to be more efficient with their labour allocation in order to recoup a few percentage points of margin lost by price-cutting.

When a product is out of stock and a customer comes in, that customer is highly likely to shop for the product in another store… perhaps unlikely to return again in the future to the original store for that product. It also means that the customer doesn’t buy additional apparel products and accessories, robbing the retailer of important add-on sales and profits. This is more critical than ever to apparel retailers since many have adopted defensive-inventory practices designed to keep only as much inventory in the store as is absolutely needed to avoid overstocks and markdown. This has put significant pressure on retailers to enhance supply chain efficiency by having real time visibility to merchandise levels in their stores and at distribution centres.

At a fundamental level, retailers are in business pressure to sell products that their customers want to buy, and they need to do everything possible to maximize sales. Having the right mix of products, maintaining adequate shelf availability, and keeping prices competitive are all key factors to their long-term success.

With an increased level of competition from low-cost manufacturers around the world, the apparel industry is under tremendous pressure to increase productivity, to improve performance, to improve production quality, and to advance the management systems.

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Technological pressure

Though the main considerations in the business pressure on apparel particularly in sourcing and manufacturing decisions are lower costs, high productivity, and better quality, however, faced with increasing labour costs, advanced technologies for garment manufacturing processes have been called upon to increase productivity and produce better quality goods, in high volume, in short time cycles, at lower costs. Thus, advanced technologies and conduciveness facing new challenges driven by the intense competition is critical for garment manufacturers to remain competitive and grow. Constant innovation and adoption of new technology become an essential element for competitive advantage in the global market because manufacturing units can maintain quick and flexible responses to market demand using the technologies.

Recent technological pressure in clothing manufacturing includes the development of robotics for the automation assembly line for garment making; high-speed sewing machines; new pressing and fusing techniques; computer-aided design; computer-aided manufacturing; and computer-aided marketing. These technologies can be used individually or in combination with other technologies to achieve the desired economies. Business pressure on top management is the commitment to technology which positively influences the technology adoption of the apparel industry.

Environmental pressure

Challenges and importance of a sustainable planet have been gained momentum to live a greener lifestyle. Apparel business has also felt the touch of it. At the garment production, the main pressure on the environment is the cutting losses, package materials and the use of accessories, such as buttons and zippers, which can contain heavy metals. Prevention of cutting losses by smart design and process control includes environmental savings of all chemicals used in processes such as sizing, de-sizing, scouring, bleaching, mercerisation, washing, dyeing, printing and finishing. A large amount of water is being used in such processing. When the clothes are used the chemicals can turn up in the water during washing or when clothes are dried after disposal of those chemicals will be released as well thereby creating pollution pressure on the environment.

Social and legal pressure

Brand companies and retailers, especially multinational corporations, have become aware of the concerns of consumers and NGOs and aware that they can contribute to sustainable development as well. As a response to the international attention about Corporate Social Responsibility issues and consumer pressure, brands such as Nike, Adidas, Reebok, Levi’s, Gap and others developed codes of conduct designed to ensure that suppliers in which they had only a contractual relationship to produce goods complied with a basic standard of workplace practices. Many textiles production companies in Asia, Latin America and East and South Europe experience this and feel sandwiched between tight production orders and a diversity of different codes and standards on Corporate Social Responsibility to comply with. Emerging pressures of NGOs, trade unions and western consumers to make multinational buyers ensure basic human rights in supply factories and also there is a demand for adequate health and safety measures in those units. Pressures from multinational buying companies to change factory working conditions and social codes of conduct introduced by different buyers have become mandatory, with non-compliance resulting in the cancellation of orders. Growing awareness of workers’ collaboration with NGOs, worldwide activist campaign for workers’ rights in developing countries, and heightened media coverage are also responsible to encourage more pressures on apparel business in social and legal front.

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Conclusion

In knitting fair,the branded apparel industry is at a crossroads to face pressure from various corners. There are several new challenges and understanding the dynamics is important for the branded apparel industry to change and adapt, or otherwise lose relevance. Several leading companies have already begun to reshape the blueprint for success by implementing leading edge supply chain capabilities combined with a holistic business process that dramatically reduces cycle times, increases visibility across the entire value chain, enables quick response to changes at retail, and ultimately delivers satisfaction to the consumer, in the form of the right product, at the right place and time, at the right price, and in the right size and color. But overall industry success and survival depends on each branded manufacturer’s ability to radically change how business is done withstanding pressures from the market, technology, environment and social and legal standards.

Source: textiles school

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