Indigo, a special case: How to win the in-out game – Denim
Denim takes a special place among modern textiles: The indigo-blue color and fashionable wash-out effects make all the difference. Long before preparing the dyeing bath, customers can benefit from our special know-how in cotton, from production of the denim fabric throughout all subsequent process steps. From spinning to garment finishing, Pulcra Chemicals offers products based mainly on natural raw materials that assure optimized processes and healthy cost-benefit ratios. Our spinning and weaving auxiliaries offer telling advantages, especially the products for continuous pretreatment of cotton and cotton mixes. They stand out particularly for their low-foaming, rapid wetting and optimal emulsifying properties and have made us market leader worldwide. Pulcra Chemicals sets standards in softening too – with processing aids for making-up which improve the touch while protecting the fabric from damage.
Dyeing jeans
The most difficult stage in the making of jeans is dyeing, a process which actually poses two problems. Pulcra Chemicals offers solutions to both. Problem number one: With denim, only the warp yarn is dyed instead of the entire fabric. Up to 4,000 parallel fibers are simultaneously washed and then pass through several successive baths. Indigo is insoluble in water and will only take when the chemistry is right. We have the formula to make it do so: The dyeing vats are injected with sodium lye and the reductant hydrosulfite, which converts the indigo into a soluble form and changes its color to yellow. Step by step, each single fiber is coated with six initially yellow, later green dye layers, with a light gray zone remaining in the center. Once the dye has been deposited on the fibers, the sodium lye and the reductant are removed from the bath and the initial blue color is restored. With our process know-how, we can design this complex process for maximized efficiency and minimized cost.
The enzyme-based wash-out look
Problem number two: Because fashion demands it, after washing, sizing, and weaving, the dye has to be partially removed from the finished fabric. Which brings us to the wash-out look. This is where Pulcra Chemicals offers outstanding competence with a new enzyme-based technology. Perpetual prewashing and the environmentally dubious stone-washing method are out. Enzymes do the job better in every way. However, besides enzymes the process does require special softeners and smoothing agents. And it takes special expertise to apply these. We are fully in touch with this technology, too.