Class 9 Weaving and Textile Design Chapter 3 Dyeing Solutions English Medium, SEBA Class 9 Weaving and Textile Design Question Answer, Class 9 Weaving and Textile Design Chapter 3 Dyeing Question Answer to each chapter is provided in the list so that you can easily browse throughout different chapter Class 9 Weaving and Textile Design Chapter 3 Dyeing English Medium Solutions and select needs one.
Class 9 Weaving and Textile Design Chapter 3 Dyeing
Also, you can read the SCERT book online in these sections Solutions by Expert Teachers as per SCERT (CBSE) Book guidelines. SEBA Weaving and Textile Design Elective Class 9 Question Answer. These solutions are part of SCERT All Subject Solutions. Here we have given Class 9 Weaving and Textile Design Chapter 3 Dyeing Solutions for All Chapter, You can practice these here.
Dyeing
Chapter – 3
| Self-Check Questions |
1. Classify dye on source of material.
Ans: Classification based on the source of materials:
Natural Dyes:
(i) Natural dyes are dyes or colorants derived from plants, invertebrates, or minerals.
(ii) The majority of natural dyes are vegetable dyes from plant sources such as roots, berries, bark, leaves, and wood.
(iii) Natural dyes have been used for many thousands of years by humans.
Synthetic Dyes:
(i) These dyes are produced synthetically by humans.
(ii) Synthetic dyes are derived from organic or inorganic compounds.
(iii) Almost all the colors seen today are synthetic dyes.
(iv) Synthetic dyes are used widely in everything from clothes to paper, from food to wood due to their lower cost, brightness, better color-fastness, and ease of application.
(v) Examples include Acid Dyes, Azo Dyes, Basic Dyes, Mordant Dyes, etc.
2. Note down any five characteristics of direct dye.
Ans: The five characteristics of direct dye are:
(i) Contains acidic or basic auxochromes.
(ii) Are soluble in water.
(iii) Are sodium salts of sulphonic acids.
(iv) Ionic in nature.
(v) An affinity for a wide variety of fibres such as cotton, viscose, silk, jute, linen, etc.
3. Name the different types of direct dye.
Ans: The classification of direct dyes:
(i) Class A: Dyes that are self-levelling, i.e., dyes of good migration or levelling properties.
(ii) Class B: Dyes that are not self-levelling, but which can be controlled by addition of salt to give level results; they are described as salt-controllable.
(iii) Class C: Dyes that are not self-levelling and which are highly sensitive to salt, the exhaustion of these dyes cannot adequately be controlled by addition of salt alone and they require additional control by temperature; they are described as temperature-controllable.”
4. Explain light and wash fastness of direct dye.
Ans: (i) Light Fastness: Dyed and printed direct colours have a moderate light fastness. Light fastness rating being about 3. A relatively short exposure to direct sunlight is enough to initiate degradation of the dye molecule and thus seen as fading of dyed or printed cellulosic textile material.
(ii) Wash Fastness: Washing fastness of direct dyed material is poor. The relatively large number of auxochromes in the direct dye anion which contributes to the aqueous solubility of these dyes contributes to the poor wash-fastness. It is due to the removal of loose dyes from the polymer system. However, the poor washing fastness of direct dyes can be improved by some after-treatment process.
5. Why after treatment is required when direct dye is used?
Ans: After Treatment of Direct Dyed Material:
The wet fastness properties (particularly washing, water and perspiration) of virtually all dyeing of direct dyes are inadequate for many end uses but notable improvements can be brought about by after treatments.
(i) Diazotisation and development.
(ii) Metal salt treatments.
(iii) Cationic fixing agents.
(iv) Formaldehyde treatment.
(v) Cross linking agents and resin treatment.
6. Name the dyes suitable for cellulosic fibre.
Ans: Dyes suitable for cellulosic fibre:
(i) Direct Dyes: Direct Fast Brown M, Chlorazol Violet N, Direct Black 80.
(ii) Reactive Dyes: Reactive Black KN-B, Procion H, Levafix EA.
(iii) Vat Dyes: Vat Blue RSN100%, Indigo Bromo 2B, Sulpher Black GLG 100%.
(iv) Sulphur Dyes: Sulpher Black BN 200%, Sulpher Blue BRN150%.
7. Name at least five properties of Vat dye.
Ans: Vat dyes have lots of properties which are required to know before and after dyeing process.
The five properties of Vat dye are:
(i) Vat dyes are insoluble in water.
(ii) Vatting process is needed for making the insoluble vat dyes into soluble form.
(iii) Vat dyes have high washing fastness in comparison to rubbing fastness. The rubbing fastness properties can be improved with special treatments to the dyed material.
(iv) Vat dyes are applied in alkaline condition.
(v) Vat dyes are expensive compared with other dyes.
8. Classify vat dye based on a) dyeing temperature b) chemical nature and origin.
Ans: There are two ways that can be subdivided vat dyes-
(i) depending upon their chemical nature and origin.
(ii) according to dyeing temperature.
Based on Dyeing temperature- According to dyeing temperature required in the dye bath vat dyes are classified as:
(i) Cold dyeing vat dyes (IK class): 20-30°C.
(ii) Warm dyeing vat dyes (IW class): 30-50°C.
(iii) Normal dyeing vat dyes (IN class): 40-60°C.
(iv) Special dyeing vat dyes (IN special class): For some black colour.
Based on chemical nature and origin- depending upon chemical nature and origin vat dyes can be categorised:
(i) Indigo and indigo derivatives.
(ii) Anthraquinone derivatives.
(iii) Carbozol derivatives.
9. How vat dye is made soluble.
Ans: This step involves the chemical reduction of the vat dye to produce the soluble, reduced or leuco form of the dye and this process is called vatting. This is achieved by the presence of sodium hydrosulphite, sodium hydroxide and water. The sodium hydroxide chemically reduces the vat dye in the alkaline conditions created by the presence of sodium hydroxide.
10. Name at least five properties of Acid dye.
Ans: The main properties of acid dyes:
(i) Anionic in nature.
(ii) Suitable for wool, silk, polyamide, and modified acrylics.
(iii) Applied from a strongly acidic to neutral pH bath.
(iv) Have no affinity for cotton celluloses, hence not suitable for cellulosic fibre.
(v) Dye molecules combine with the fibre polymer by ionic bonds or salt linkages.
(vi) Good light fastness.
(vii) Washing fastness depends upon the levelling characteristics of the acid dye used.
11. Name at least five properties of Basic dye.
Ans: The properties of Basic dye:
(i) Basic Dyes are cationic soluble salts of coloured bases.
(ii) The outstanding characteristics of the basic dyes are brilliance and intensity of their colors.
(iii) Many of the basic dyes are sparingly soluble in water. The addition of glacial acetic acid helps to dissolve the basic dye quickly in water.
(iv) These dyes show a very high affinity towards wool, silk, and acrylic fibre, but have no affinity towards cellulosic fibres.
(v) The basic dyes are poor fastness to light and vary with regard to washing fastness from poor to moderate.
12. Name at least five properties of Reactive dye.
Ans: The properties of Reactive dye:
(i) Reactive dyes are anionic dyes, which are used for dyeing cellulose, protein, and polyamide fibres.
(ii) Reactive dyes are found in powder, liquid, and print paste form.
(iii) During dyeing, the reactive group of this dye forms a covalent bond with the fibre polymer and becomes an integral part of the fibre.
(iv) Reactive dyes are soluble in water.
(v) They have very good light fastness.
13. Classify reactive dye on the basis of dyeing temperature.
Ans: Classification of Reactive Dye on the Basis of Dyeing Temperature:
(a) Cold brand: These types of dyes contain reactive group of high reactivity. So dyeing can be done in lower temperature i.e. 250 -500C. Example: Procion M, Red M8B.
(b) Medium brand: This type of dyes contains reactive groups of moderate reactivity. So dyeing is done in higher temperature than that of cold brand dyes i.e. in between 400 -600C temperatures. Example, Remazol, Livafix are medium brand dyes.
(c) Hot brand: This type of dye contains reactive groups of least reactivity. So high temperature is required for dyeing i.e. 600 -900 C temperature is required for dyeing. For example Procion H, Cibacron are hot brand dyes.
14. Explain how reactive dye is fixed on fabric.
Ans: Fixation of dye means the reaction of reactive group of dye with terminal –OH or-NH2 group of fibre and thus forming strong covalent bond with the fibre. This is an important phase, which is controlled by maintaining proper pH by adding alkali. The alkali used for this creates proper pH in dye bath and do as the dye-fixing agent.
15. Name a dye suitable for silk yarn.
Ans: A suitable dye for silk yarn is Acid dye.
Hi! my Name is Parimal Roy. I have completed my Bachelor’s degree in Philosophy (B.A.) from Silapathar General College. Currently, I am working as an HR Manager at Dev Library. It is a website that provides study materials for students from Class 3 to 12, including SCERT and NCERT notes. It also offers resources for BA, B.Com, B.Sc, and Computer Science, along with postgraduate notes. Besides study materials, the website has novels, eBooks, health and finance articles, biographies, quotes, and more.
