Dyeing device and process using indigo and other colorants

A continuous process for dyeing a yarn using indigo comprising the steps of:

• providing a continuous dyeing device comprising,
• at least a first and a second dyeing compartments each adapted to contain a dyeing bath,
• at least one squeezing element interposed between the first and the second dyeing compartments,
• at least one means for heating and/or dehydrating the yarn, the at least one means for heating and/or dehydrating increasing diffusion of a colorant in a fiber of the yarn and absorption of the colorant in the yarn, the at least one means for heating and/or dehydrating being located between the first and the second dyeing compartments and downstream of the at least one squeezing element,
• a hermetically sealed chamber containing, at least partially, the first and the second dyeing compartments, the at least one squeezing element, and the means for heating and/or dehydrating the yarn, and
• at least one second squeezing unit positioned outside the hermetically sealed chamber downstream of said second dyeing compartment;
• immersing the yarn in said first compartment containing the dyeing bath;
• squeezing the yarn upon exit from the dyeing bath of said first compartment;
• heating said yarn to increase the diffusion of the colorant in the fiber and to dehydrate the yarn, thereby increasing the absorption of the colorant in the second compartment;
• immersing said yarn in the dyeing bath contained in said second compartment;
• performing a second squeezing action on the yarn upon exit from said second compartment;
• and
• subjecting the yarn to oxidation.

A continuous process for dyeing a yarn using sulphur colorant comprising the following steps:

• providing a continuous dyeing device comprising,
• at least a first and a second dyeing compartments each adapted to contain a dyeing bath
• at least one squeezing element interposed between the first and the second dyeing compartments,
• at least one means for heating and/or dehydrating the yarn, the at least one means for heating and/or dehydrating increasing diffusion of a colorant in a fiber of the yarn and absorption of the colorant in the yarn, the at least one means for heating and/or dehydrating being located between the first and the second dyeing compartments and downstream of the at least one squeezing element,
• a hermetically sealed chamber containing, at least partially, the first and the second dyeing compartments, the at least one squeezing element, and the means for heating and/or dehydrating the yarn, and
• at least one second squeezing unit positioned outside the hermetically sealed chamber downstream of said second dyeing compartment;
• immersing said yarn in said first compartment containing the dyeing bath with sulphur colorant;
• squeezing the yarn upon exit from the dyeing bath in said first compartment;
• immersing said yarn in said second compartment containing a the dyeing bath with sulphur colorant;
• squeezing the yarn upon exit from said second compartment;
• and
• subjecting the yarn to steaming.

A continuous process for dyeing a yarn using indanthrene colorant comprising the following steps:

• providing a continuous dyeing device comprising,
• at least a first and a second dyeing compartments each adapted to contain a bath,
• at least one squeezing element interposed between the first and the second dyeing compartments,
• at least one means for heating and/or dehydrating the yarn, the at least one means for heating and/or dehydrating increasing diffusion of a colorant in a fiber of the yarn and absorption of the colorant in the yarn, the at least one means for heating and/or dehydrating being located between the first and the second dyeing compartments and downstream of the at least one squeezing element,
• a hermetically sealed chamber containing, at least partially, the first and the second dyeing compartments, the at least one squeezing element, and the means for heating and/or dehydrating the yarn, and
• at least one second squeezing unit positioned outside the hermetically sealed chamber downstream of said second dyeing compartment;
• immersing said yarn in said first compartment, wherein the bath is a pigmentation bath with indanthrene colorant;
• squeezing the yarn upon exit from the pigmentation bath in said first compartment;
• heating and dehydrating said yarn, in order to prevent hydrolysis of the bath in the second compartment;
• immersing said yarn in the bath contained in said second compartment, wherein the bath is a chemical bath;
• second squeezing of the yarn upon exit from the second compartment;
• and
• subjecting the yarn to steaming.

A continuous process for dyeing a yarn using reactive colorants according to a two stage method, the continuous process comprising the following steps:

• providing a continuous dyeing device comprising,
• at least a first and a second dyeing compartments each adapted to contain a bath,
• at least one squeezing element interposed between the first and the second dyeing compartments,
• at least one means for heating and/or dehydrating the yarn, the at least one means for heating and/or dehydrating increasing diffusion of a colorant in a fiber of the yarn and absorption of the colorant in the yarn, the at least one means for heating and/or dehydrating being located between the first and the second dyeing compartments and downstream of the at least one squeezing element,
• a hermetically sealed chamber containing, at least partially, the first and the second dyeing compartments, the at least one squeezing element, and the means for heating and/or dehydrating the yarn, and
• at least one second squeezing unit positioned outside the hermetically sealed chamber downstream of said second dyeing compartment;
• immersing said yarn in said first compartment, wherein the bath is a dyeing with the reactive colorants;
• squeezing the yarn upon exit from the bath in said first compartment;
• heating and dehydrating said yarn, in order to prevent hydrolysis of the dyeing bath contained in the second compartment;
• immersing said yarn in said second compartment, wherein the bath is in a saline alkaline bath;
• second squeezing of the yarn upon exit from the second compartment;
• and
• subjecting the yarn to steaming.