UNIT – II

TWO MARKS

Dyeing

1. Give a classification of colorants for textile?

2. Distinguish between i) a dye and pigment & ii) a readymade dye

and an ingrain dye?

3. Indicate the fibres for which the following dyes have affinity:

a. Reactive dyes b. Acid dyes c. vat dyes g. disperse dyes h. direct

dyes?

4. Explain with suitable examples with following terms:

a. Substantivity or affinity b. Exhaustion c. M:L ratio d. shade %

5. List the common dyeing assistants used stating functions?

6. What do you understand by zeta potential?

7. Explain the terms absorption and desorption?

8. Write down the liquor ratio commonly used in the following

machines a. Jigger b. Kier c. Winch d. HTHP machines for yarn and

fabric e). Soft overflow jet dyeing f). yarn package dyeing

9. What do you understand by the term dyeing? What are the physic

chemical steps involved in it?

10. What classes of dye are suitable for dyeing cotton fabric?

11. What are the advantage & disadvantage of a beam dyeing machine

12. What are steps involved for mechanism of

dyeing

13. . Give the relative strength,dyes and suitable fibers for following

bonds a. van der Waals’ forces b. Hydrogen bonds c. salt

linkage d. Covalent bonds?

14. Direct dyes

15. Why are direct dyes also called as ‘substantive’? List any four

properties of direct dyes?

16. How are direct dyes classified?

17. Explain clearly the effect of electrolyte in the direct dyeing on

cotton?

18. Describe the process of application of direct dyes to cotton?

19. What are the various after treatment given to direct-dyed goods?

20. Reactive dyes

21. Why are reactive dyes so called? Classify the reactive dyes with

examples on the basis of application?

22. Classify reactive dyes according to their reaction mechanism.

Briefly describe the bifunctional reactive dyes?

23. List any four properties of reactive dyes. What do you understand

by cold brand and hot brand?

24. Why do reactive dyes react preferentially with cellulose than with

water?

25. In reactive dyeing, Explain

a) Why salt is added in two or more portion

b) Why Glauber’s salt is preferred in the case of dyes

26. Why is after-treatment necessary for the reactive dyed goods?

27. What are the advantages of reactive dyes over other dyes classes

with respect to dyeing cellulosic material?

28. Write down the chemical structure of cold brand, hot brand, a vinyl

sulphone and an HE-brand reactive dye?

12 MARKS

29. Discuss the factors that affect the performance of reactive dyeing?

30. Explain the effect of M : L ratio in reactive dyeing?

31. Explain the principle of dyeing cotton with vinyl sulphone and

triazine type reactive goods?

32. Explain the application of reactive dyes by the pad steam process?

33. Write down the chemical structure of cold brand, hot brand, a vinyl

sulphone and an HE-brand reactive dye?

34. Explain the pad batch technique of dyeing cotton fabric with vinyl

sulphone reactive dyes with neat diagram

35. Explain dyeing of cotton fabric with hot brand reactive dyes with

chemical reactions

36. Explain dyeing of cotton kinnited fabric with cold brand reactive

dyes using soft flow dyeing m/c

37. Explain the pad batch technique of dyeing cotton fabric with vinyl

sulphone reactive dyes?

Dyeing with Reactive Dyes (practical)

38. What kinds of dye-fibre bonds occur mainly between reactive dyes and cellulose fibres?

39. What steps are involved in the application of a reactive dye to a cellulose fibre?

40. In the first step of reactive dyeing, the reactive dye acts like a direct dye. Is this statement true or false?

41. Explain what happens in the second step of reactive dyeing?

42. What dyeing assistants are used in reactive dyeing? State their functions.

43. State the after-treatment that is done after reactive dyeing. State the recipe/conditions of such treatment.

44. Indicate the colour fastness properties of reactive dyes.

45. Give a list of reactive dyes brands available commercially. Which of these are mainly used in industry?

46. State the features of the M, H and HE brands of reactive dye.

47. What are the features of the ME and VS brands of reactive dye

48. Name the factor to which reactive dyes have poor colour fastness.

49. Classify reactive dyes by chemical structure and based application

Dyeing with Vat Dyes

50. What are vat dyes?

51. State the sub-classes of vat dyes. How do they differ from each other?

52. How would you classify the vat dyes according to the chemical

constitution?

53. What is vatting? Write down the properties of vatting?

54. Write down the quantities of caustic soda and sodium hydrosulphite

required for the IK, IW, IN, and IN spl groups of vat dyes?

55. State the different methods of oxidation of vat dyed goods?

56. What fibres can be dyed with vat dyes?

57. How would you dissolve a vat dye?

58. What physical changes occur in a vat dye solution during dissolution of the dye?

59. What chemical changes occur in a vat dye during dissolution and dyeing?

60. What are the dyeing conditions for vat dyes?

61. What are the functions of the auxiliaries used in vat dyeing?

62. How can oxidation be brought about after the dyeing step using vat dyes?

63. State the classes of vat dye for which extra salt is required for exhaustion.

64. What changes are brought about in vat-dyed material by the soaping treatment'!

65. What kinds of dye-fibre bond occur mainly between vat dye and a cellulose fibers

66. Name some machines that are used in industry for the vat dyeing of cotton.

67. What are the colour fastness properties of vat dyes?

68. Write down the steps involved in the dyeing of cotton with vat

dyes?

69. Which of the following industrial processes can be used for vat dyeing cotton fabric? a) Jigger dyeing b) Beam dyeing

c) Pad-jig method dl Continuous dyclI1g

12 MARKS

70. Explain, with chemical equation, the various steps in vat dyeing?

71. Explain the chemistry and application of vat dyes to cotton?

72. Describe the process of application of vat dyeing on cotton using

jigger / winch /soft flow machine with neat sketch

73. Describe the process of application of vat dyeing on cotton fabric

74. Disperse dyes

75. Why are disperse dyes called so? List any four properties of

disperse dyes?

76. How are disperse dyes classified?

77. Explain the theory of disperse dyeing?

78. List the auxiliaries used in disperse dyeing of polyester stating their

function?

79. Write the mechanism of dyeing polyester with disperse dyeing?

80. What is the principle of carrier dyeing?

81. What is the principle of HTHP dyeing?

82. What is the principle of Thermosol dyeing?

83. State the factors to be considered while selecting a carrier for

polyester dyeing?

84. Write down the precautions to be taken during carrier dyeing?

85. List the different machines used for dyeing polyester with disperse

dyes?

86. List the different method used for dyeing polyester with disperse

dyes?

87. Explain the reduction clearing treatment given to the polyester dyed

goods?

88. What are the advantage and disadvantage of a beam dyeing

machine?

89. What are the advantage and disadvantage of a jet dyeing machine?

90. State the steps involved in thermosol process?

91. What are the advantages of the thermosol process?

92. Why is heat setting necessary for polyester fabric dyeing?

93. Explain the dyeing of polyester cotton blended fabric disperse / vat

dyes?

94. Explain the dyeing of polyester cellulose blended fabric with

disperse / reactive dyes?

95. Explain the rapid inverse dyeing process for polyester cellulose

blended fabric?

96.

97. Dyeing machinery

98. What are the various forms in which textile material dyed?

99. What are the essential requirements of a dyeing machine?

100. Explain the construction and working process of cabinet

dyeing machine?

101. Why is yarn package dyeing preferred to hank dyeing?

102. Explain the construction and working process of a winch

machine?

103. State the types of fabric generally dyed in (1) a jigger (2) a

winch (3) a cabinet dyeing machine (4) a package dyeing machine?

104. What are the advantages of pad dyeing machinery over the

other method?

105. Compare the colour fastness properties of the water-soluble

dyes?

106. Compare the colour fastness properties of the water-

insoluble dyes?