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Slovenia - Dying

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Dyes are used to impart color to materials. There are two main types - dyes and pigments. Dyes are soluble organic compounds like synthetic dyes which can contain harmful chemicals. Pigments are finely ground insoluble particles. Natural dyes are plant-based or from insects but fade faster. Direct dyes are water-soluble and used for direct coloring. Azo dyes contain nitrogen groups and are made through a chemical reaction involving diazotization. Indigo is extracted from plants and involves reduction and reoxidation reactions. Disperse dyes are insoluble but used for polyester and require high temperatures.

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Slovenia - Dying
Dye Substance used to import colour to various materials Organic compounds (carbon) Pigment Finely ground solids dispersed in a liquid or blended with other materials Inorganic or organic compounds Give brighter colours Synthetic dyes can be harmful: mercury, lead, chromium, copper, sodium, chloride, toulene, benzene Differnet things used to dye fabric: boiled shellfish, plants, mud Natural dyes: Plant-based, insects Fade faster
DIRECT COLORING Direct dye = substantive dye water soluble compounds benzidine derivatives cheap, easily applied, bright colours positively and negatively charged groups Methyl orange Congo red: belongs to a group of azo dyes derived from benzidine synthetic dye mordant a substance used to fix the colour to cotton fibers histology, acid-based indicator
COLORING AS A RESULT OF A CHEMICAL REACTION Azo dye is a synthetic organic dye, containing nitrogen as the azo group (-N=N-) Several categories, defined by fibers or methods of application aromatic amino compounds diazotization Attachment of an intermediate to a phenol or aniline
Indigo dye Organic compound Extracted from the leaves of Indigofera and Isatis Indican Simpler compounds: reduction to the soluble yellow leucoindigo reoxidized to indigo
DISPERSE DYES Water-insoluble dyes Dye polyester and acetate fibers The smallest molecules Based on an azobenzene or anthraquinone molecule High temperatures + nitro, amine, hydroxyl groups attached
Slovenia - Dying

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Slovenia - Dying

  • 2. Dye Substance used to import colour to various materials Organic compounds (carbon) Pigment Finely ground solids dispersed in a liquid or blended with other materials Inorganic or organic compounds Give brighter colours Synthetic dyes can be harmful: mercury, lead, chromium, copper, sodium, chloride, toulene, benzene Differnet things used to dye fabric: boiled shellfish, plants, mud Natural dyes: Plant-based, insects Fade faster
  • 3. DIRECT COLORING Direct dye = substantive dye water soluble compounds benzidine derivatives cheap, easily applied, bright colours positively and negatively charged groups Methyl orange Congo red: belongs to a group of azo dyes derived from benzidine synthetic dye mordant a substance used to fix the colour to cotton fibers histology, acid-based indicator
  • 4. COLORING AS A RESULT OF A CHEMICAL REACTION Azo dye is a synthetic organic dye, containing nitrogen as the azo group (-N=N-) Several categories, defined by fibers or methods of application aromatic amino compounds diazotization Attachment of an intermediate to a phenol or aniline
  • 5. Indigo dye Organic compound Extracted from the leaves of Indigofera and Isatis Indican Simpler compounds: reduction to the soluble yellow leucoindigo reoxidized to indigo
  • 6. DISPERSE DYES Water-insoluble dyes Dye polyester and acetate fibers The smallest molecules Based on an azobenzene or anthraquinone molecule High temperatures + nitro, amine, hydroxyl groups attached