Finishing of Silk Fabric

Samiksha Shastri
Department of Textile Manufactures
Veermata Jijabai Technological Institute,Mumbai

Types of Finishes on Silk Fabric:

  • Durable press finish
  • U V resistant Finish
  • Insect Resistant finish
  • Calendering
  • Weighting

Durable press Finish:

Why do we need this finish?
Silk fabrics have low wet and dry resiliency because of which they  wrinkle easily.
The cross linking group of silk fabric is Carboxylic acid.

Chemicals used:
Glyoxal, Citric acid and DMDHEU

Catalyst:
Aluminum Sulphate, Magnesium Chloride & Sodium Hypophosphate

U V resistant finish:

Why do we need this finish?
  • Long term exposure to UV light can result in acceleration of skin ageing, photo dermatosis (acne), phototoxic reactions to drugs, erythema (skin reddening), sunburn, increased risk of melanoma etc.
  • Silk fibres offer little protection to UV radiation since the radiation can pass through without being markedly absorbed. Since the SPF ( Solar protection factor) of silk is 7 which is very less we require this finish.
Insect resistant finish:

Need:
Insect resist finishes are chemical treatments that protect wool and other animal fibres from attack by the larvae of certain moths and beetles. Only keratin containing fibres are damaged by these insects.

Mechanism:
There are 2 types
Digestion-affecting poisonous 
Nerve poisonous

Applications:
  • Insect resist finishes are most commonly applied during dyeing.
  • Application of insect resist finishes during scouring.

Calendering:
  • The main function of calendering is to provide a smooth fabric surface, light lustre, and improved hand. 
  • This is the technique used to influence the handle and appearance of the fabric. In most cases, silk is only calendered in the cold stage, which produces a soft handle. 
  • With hot calendaring higher lustre is obtained, but it has to be determined in each case in order to prevent negative influence. 

Weighting:
  • The weight of silk is lost during the process of degumming. The manufacturer purchases silk by weight and to make up his loss, he does weighting of silk fabric with metallic substances such as stannic chloride, sodium phosphate, iron salt, logwood etc.
  • Weighting is done during the dyeing process.
  • Weighted silk is less compactly woven when compared to the unweighted silk and lesser silk is used in the fabric construction.
  •  Apart from lowering the cost of silk, weighting gives it crispness, luster and a firm feel.

References:

Post a Comment

0 Comments