#Colorcast dye method how to#

With the Thermosol process, a pad-dry heat technique developed by the DuPont Company, temperatures of 180–220 ☌ (356–428 ☏) are employed with contact times on the order of a minute.

Dyeing at higher temperatures (120–130 ☌ ) under pressure avoids the need for carriers. The transfer mechanism is unclear, but it appears that the fibres loosen slightly to permit dye entry and, on cooling, revert to the original tightly packed structure. Transfer into the fibre from a boiling dye bath is aided by carriers (e.g., benzyl alcohol or biphenyl). These disperse dyes were originally developed for acetate rayon but became the fastest growing dye class in the 1970s because of the rapid increase in world production of PET, which can be dyed only with small disperse dyes. These synthetic fabrics are dyed by immersion in an aqueous dispersion of insoluble dyes, whereby the dye transfers into the fibre and forms a solid solution. Penetration of the fabric by the dye is more difficult with the hydrophobic synthetic fibres of acetate rayon, PET, and acrylics, so an alternate dyeing technique is needed. In many cases, the fabric is pretreated with metallic salts or mordants to improve the fastness and to vary the colour produced by a given dye ( see above Natural dyes: Mordants). Under these conditions, the dye is more soluble and the wettability of natural fibres is increased, improving the transport of dye molecules into the fabric. SpaceNext50 Britannica presents SpaceNext50, From the race to the Moon to space stewardship, we explore a wide range of subjects that feed our curiosity about space!ĭirect, or substantive, dyes are applied to the fabric from a hot aqueous solution of the dye.Learn about the major environmental problems facing our planet and what can be done about them!

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#Colorcast dye method how to#

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