Space Dyeing Techniques

"Space dyeing is a process of dyeing of yarn in which multiple colors are applied along the length of each strand of yarn which may or may not repeat after a fixed interval."

Figure: Space Dyed Yarn

Space dyeing can be achieved through several methods:

1. Knit-De-Knit Process
2. Warp Yarn Printing/Dyeing Process
3. Pot Skein Dyeing Process
4. Package Form Dyeing Process
5. Hank Form Dyeing Process
6. Continuous Dyeing Process
7. Spraying of colors onto the skeins of yarn.

The Knit de Knit Process

In the knit-de-knit process, the yarn is first knitted into tubular fabrics (socks) and then overall length of all loops is dyed to a solid color. All solid-colored dyed loops of tubular knitted fabric are dyed with up to seven different colors. After dyeing, tubular fabrics are passed through an ager, where they are steamed for 3-10 minutes in saturated steam.

Mordant is used to chemically bond the dye with skein. This is followed by rinsing, washing, finishing and drying.

The socks are then de-knitted, producing contrast effect between overprinted and base colors because the overprinted color does not penetrate at the yarn crossing points.

These yarns usually have short (1/8-1/4 inches) spaces of color. In this process, the dye penetrates the loops of the yarn but since it does not readily penetrate the areas of the yarn where it crosses itself, alternating dyed and undyed spaces appear.

Warp Yarn Printing/Dyeing Process

Warp yarn printing is roller printing applied to multiple strands of yarns from the warp system which are continuously printed at specific space intervals with different colors. These yarns have usually long spaces of each color. Typical color length is 3-7 inches.

Warp printing is roller printing applied to warp yarns before they are woven into a fabric. Fine white or neutral colored filling yarns are generally used for weaving so that the design on the warp will not be obscured. Warp printing is used for expensive cretonnes and upholstery fabrics.

Warp yarns can also be dyed with a base color, followed by spraying of dye colors at specific intervals. Mordants are used to chemically bond the dye to substrate. These yarns when woven into fabric produces eye-catching designs.

Pot Skien Dyeing Process

Skein is added to the pot (dye bath) having water before turning on the heat. This helps in the reduction of movement of dye in the dye bath when added, enabling maximal separation between the colors. Water present in the pot is boiled and skein is adjusted in the pot with a spoon.

Different colored dye is added into the pot with each drop in a different spatial area. There is no stirring the contents of pot in whole process as we want as little movement in the dye bath as possible. The skein is left in the pot undisturbed until all of the dye has been absorbed into the skein. When skein is cool enough to touch, it is washed with warm water and mild soap until the rinse water runs clear.

Multicolored skein is obtained in this process with each strand of yarn having random colors on it at random intervals which produces very distinct designs when transformed into fabric. Dye is fixed on skein with the help of mordant.

Space Dyeing in Package Form

Various package dyeing machines, with a single package dyeing capacity are available in which we can dye up to 8 colors, each color is having a different feed tank as well as a injector pump. The color is injected at a fixed place at a high pressure and collected through a vacuum. The resulting package has different patches having different colors which may or may not be at fixed intervals and, hence space dyed yarns are obtained.

This type of process is used to create beautiful patterns of dyed patches on package, with good sharpness. The dyed time is extremely low. The packages are taken for further color fixation and washing on another set of machines such as autoclave and yarn dyeing machines.

A major advantage of package dyeing is its contribution to ‘quick response’ processing, in which yarn can be prepared on package, ready to dye as orders are received, thereby shortening the processing cycle. Many important products of package-dyed yarn are textured products, sewing threads, regular spun acrylic yarns, high bulk acrylic yarns, continuous yarns and automotive yarns.

Space Dyeing in Hank Form

This is similar process to produce tie dye (Tie dye is a technique for dying natural fabrics that results in interesting, colorful patterns) effects in knitting yarn and embroidery threads.

The processes which can be employed for space dyeing in hank form are:

• By spraying the colors on a layer of hank at fixed places, which are fixed through hank with pressure and collected underneath by vacuum. The yarns are dried and cured for color fixation and the washed.
• The roller dyeing machines can be used very effectively for space dyeing with vat and naphthol colors. Even reactive dyeing is also possible with a slight modification of machine for mercerized cotton as well as rayon.
• Space dyeing machine with fiber carrier can be used for space dyeing in polyester hank, but the method involves a higher labor cost. But desired effects can be obtained using this method. Dye is fixed on the hank with the help of mordants.

The Continuous Dye Process

In the continuous yarn dyeing process, the yarn is dyed as a single or plied yarn and color is applied by air jet. This process allows for yarn to have either long or short spaces of color. Other methods have also been used in the continuous space dyeing of yarns. Acrylic yarns with almost 250 - 500 meter length have been successfully dyed using CSIRO yarn dyeing applicator with an intake of 17.5% moisture. Wool and Nylon yarns are also successfully space dyed using Acru-Strand process.

Spraying of Color onto Yarns

Spray dyeing onto yarns is a method of dyeing yarns by spraying dye onto them using a spray bottle or a high-pressure spraying technique. This method is used to achieve even impregnation of dye onto the yarns.

The process involves spraying the dye onto the yarn with a spray, receiving the yarn transferred through the dye spraying device and drying it in the drying device, and continuously passing the dried yarn through the drying device through the steaming device to apply the dye to the yarn. This is done many times to achieve desired colors and then finally dried and winding is done. Beautiful multi color yarns are produced in this way. This has many applications especially in fancy garments and textiles.