The dyeing of fibers is an energy-intensive process. The most widely used regular polyester fibers face challenges such as difficult-to-control dyeing processes, increased dyeing costs, higher dye content in wastewater, and significant damage to fiber properties. Moreover, conventional dyeing methods pose environmental concerns.
Easy dyeing fibers align with environmental requirements and aim to reduce costs and enhance competitiveness. Through technological improvements, the fibers exhibit lower polymerization and spinning temperatures compared to conventional polyester, resulting in approximately 15% reduced energy consumption. The dyeing process is conducted under atmospheric pressure, eliminating the need for alkali reduction in fabric treatment and reducing water and energy consumption by approximately 20%.
Easily dyed fibers, besides achieving high dye uptake with low energy consumption, create vibrant colors while maintaining fabric hand feel, thus contributing to a more colorful fiber world.
Addressing Cost Challenges
Conventional polyester fibers, despite their numerous excellent properties, face challenges in dyeing due to their tight molecular structure, high crystallinity, and lack of polar groups. Dyeing typically requires dispersed dyes at high temperatures (120-135°C) and high pressure or in the presence of carriers to achieve high dye uptake. When blended with natural or some chemical fibers, issues such as difficult-to-control dyeing processes, increased dyeing costs, higher dye content in wastewater, and elevated wastewater treatment costs arise, causing significant damage to fiber properties. Therefore, modifying the dyeing process of polyester fibers has been a key focus in industry research and development.
Classification and Characteristics
Easy dyeing fibers mainly fall into two categories.
The first category is room temperature and atmospheric pressure dyeable polyester without a carrier. It employs methods such as copolymerization or segmented copolymerization and blending to enable dyeing with dispersed dyes at temperatures below 100°C without needing a carrier. EDDP Chip is the raw material for such easily dispersed dyeable polyester. For more information, you can click https://www.polyestermfg.com/easy-disperse-dyeable-polyester-chip/.
The second category involves cationic dyeable polyester. Cationic dyes, named for the positive charge on their dye molecules, offer advantages such as a complete color spectrum, bright colors, low cost, and simple dyeing processes. Cationic dyeability is imparted to polyester through various methods such as copolymerization, graft copolymerization, and additive methods. Cationic dyeable fibers significantly improve the dyeing performance of polyester, enhance softness, reduce crystallinity, and achieve superior dyeing results.
Easy dyeing fibers allow fabrics to obtain a wide range of colorful shades through simple dyeing processes. By interweaving easy dyeing fibers with ordinary polyester and other fibers and adjusting the ratio and patterns of cationic and polyester components, various patterns can be created. Therefore, the use of easy dyeing fibers can produce fabrics with rich colors.
Easy dyeing fibers continue to undergo modifications, with their comprehensive performance improving in recent years. The previously mentioned super-soft dyeing copolyester fiber and fabric dyeing technology start with the design of the polyester macromolecular structure. Optimization of esterification and condensation processes addresses key technologies such as self-catalysis and ionization-induced aggregation of cationic dyeable groups. This ensures controllable molecular weight and sequence distribution of super-soft easy dyeing copolyester. The selection of multiple modified combinations results in soft and easy-to-dye fibers. Fabrics made from super-soft dyeing copolyester exhibit advantages such as super-softness, resistance to pilling, soft gloss, vibrant colors, and high dyeing fastness. Polymerization and spinning temperatures are lower than conventional polyester, reducing energy consumption by approximately 15%. The atmospheric pressure dyeing process eliminates the need for alkali reduction in fabric treatment, reducing water and energy consumption by about 20%.
Island Fiber in Easy Dyeing Fibers
Easy dyeing varieties in island fibers are representative. Island fibers disperse one polymer within another in a state resembling “islands” in the fiber cross-section, with the matrix acting as the “sea.” From the cross-section perspective, the components form a continuous, dense, and evenly distributed structure.
During production, island fibers have the same fineness as conventional fibers. However, using a solvent to dissolve the “sea” component yields bundled ultra-fine fiber bundles. The composition of island fibers (generally two components) typically involves using polyester (PET), polyamide (PA), polyacrylonitrile (PAN) as the island and polyethylene (PE), polyamide (nylon 6 or nylon 66), polypropylene (PP), polyvinyl alcohol (PVA), polystyrene (PS), acrylic ester copolymers, or modified polyester as the sea. Island easy dyeing fibers use composite spinning, allowing islands of PET and PTT matrix to be orderly distributed in a sea of polystyrene. During fabric finishing, alkali reduction completely hydrolyzes and removes the sea component, separating the island component to form ultra-fine fibers with a diameter of 0.06D. The surface features micro-pores favorable for dye absorption, resulting in deep dyeing characteristics.
Island easy dyeing fibers represent a new environmentally friendly fiber with excellent stain resistance, easy dyeability, soft feel, elasticity, and superior performance compared to elastic fibers like spandex. It is easier to process and possesses characteristics such as dryness, stiffness, wrinkle resistance, and strong resilience, providing fabrics with shape recovery.
Island easy dyeing fibers can achieve a dye depth of more than 3 levels compared to ordinary island silk, with a color fastness reaching over 4 levels, addressing the shortcomings of regular island silk. Moreover, through fabric design and processing, utilizing the extremely fine characteristics of island fibers, various special fabric styles such as faux cashmere, faux suede, and ultra-high-density fabrics can be obtained. These fabrics find wide applications in clothing, fashion, luggage, indoor products, and industrial fields.
It is worth emphasizing that many properties of faux suede fabrics developed using island fibers currently match or surpass natural suede. This has gained popularity among users.
Simultaneously, leveraging the easy dyeing characteristics of easy dyeing fibers can create different fabric styles. Easy dyeing fibers, when interwoven or blended with wool, silk, protein fibers, spandex, acetate fibers, and ordinary polyester, can achieve simultaneous dyeing, resulting in fabrics with unique styles.