What are scavengers ? How they are used in easy care finish ?

1. Uttar Pradesh textile technology
institute
Kanpur
SUBJECT: FINISHING
DATE OF SUBMISION: 20 April 2020
TOPIC: What are scavengers ? How they are used in easy care finish ?
SUBMITTED TO:
Alka Ali Ma'am
SUBMITTED BY:
Vijay Prakash
Textile Chemistry
1704460060

2. CONTENT :
1. DEFINITION
2. OBJECT
3. WHAT ARE SCAVENGERS ?
4. TYPES OF THE SCAVENGERS
5. HOW SCAVENGERS ARE USED IN EASY CARE FINISH ?

3. SCAVENGERS :
Scavengers are added in the finishing bath to block the
release of formaldehyde By reacting with monomeric
formaldehyde.

4. TYPES OF THE SCAVENGERS :
 Scavengers are of two types:
1. NITROGEOUS COMPUNDS
2. ALCOHOLS

5. SCAVENGERS ARE USED IN EASY CARE FINISH
 The nitrogenous additives not only react with HCHO to form N-methylols, but
they also react with the pendent N-methylols to form methylene brides. They
compete with the cellulose and when enough additive is present to lower
HCHO release , cellulose cross-links are reduced, resulting in a lower DP
performance, As additional N-H GROUP are formed, chlorine damage
increases and light fastness is reduced. Urea, ethylene urea and carbohydrazide
are some of the nitrogenous scavengers.
 High boiling alcohols also act as scavengers and lower HCHO release . They
block pendent N-methylol groups. The blocked end groups are more stable
than the hydroxymethyle, so the equilibrium of the reverse reactions is shifted.
These additives also compete with cross-linking, therefore DP ratings are
somewhat diminished . Because there are no N-H group, chlorine resistance
and light fastness problems are reduced . Nitro alcohols, ethylene glycol, DED
and sorbitol are some of the alcoholic scavengers.

6. Aftertreatment with Formaldehyde
Scavengers
 Formaldehyde scavengers, used in durable press finishing of textiles, were used
for the aftertreatment of the flame retardant finished fabric. Different
concentrations and formulations of scavengers were used. Aftertreatment with
acetoacetamide was done as it was a Rhodia’s patented method of aftertreatment
and was used in this research for the comparison purpose.
 Distilled water was used for making the solutions. Fabric samples weighing 2 g
were padded with solutions of 50 ml in a beaker and passed through the squeeze
rollers of the padder with 95% (dry on wet) pick up. After padding the samples,
the samples are dried and packed in polyethylene bag to be taken for testing the
free formaldehyde contents by the test method ISO 14184-1 (water extraction
method).

8. Thank you