Experiment no:01
Experiment Name : Scope of pretreatment of cotton knit fabric with &
without chemical same temperature & different time duration.
Objective:
To know about the pretreatment & dyeing process.
To know the process of scouring & bleaching at the same time.
Compare the result of sample which treated with chemical & without
chemical.
To know about the function of all chemical which are used.
What types of result are vary according to the different time duration
that’s know.
Introduction :
Pretreatment is the process of removing natural impurities present in the
cotton fiber. The natural impurities are pectin's, pectose, ash, wax, mineral
compounds natural gray colore etc. materials. If those impurities present in
the cotton fibers are not removed, then it will be difficult to dye or print the
fabric uniformly.So for removing this impurities & also increase the
absorbency scouring and bleaching is need.Mainly its need for uniformly
dyeing and printing.
Working procedure:
Our group is B & serial 3 . So in B group for scouring & bleaching no
chemical is used.Here 120°C and 40 minute time duration.
Scouring & bleaching:
Chemical: No chemical
Temperatur:120°C
Time: 40 minute
M:L = 1:15
Sample weight: 5gm
Dyeing Recipe:
Shade :1%
Glubar salt:30 gm/L
Na₂CO₃: 10 gm/L
Wetting agent:1 gm/L
Sequestering agent: 1 gm/L
Leveling agent: 1 gm/L
Time:45 minute
Temperatur:60⁰C
M:L=1:15
Hot wash:
Detergent: 1 gm/L
Time: 10 minutes
Temperature: 600 C
Neutralization:
CH3COOH: 0.5 gm/L
Time: 5 minutes
Temperature: 300 C
Drop Test: Direct dye 1% solution
Fig:Drop tested sample.
Result : Average 13 secund & Scattered shape
Result of all groups
Discussion:
Here group 2 is standard, but finally all of the tested result of group 1
is batter then the standard group 2. So here known that the time
duration is 70 minute is perfect.
Group 2 & group 3 are same time duration, but in group 3 others
substance chemical (wetting agent, sequestering agent, defoming
agent etc) are not used, only NaOH & H₂O₂ is used . For this reason
here scouring & bleaching has been poor so absorbency will be
poor.So for this reason drop test & other tested result is poor then
the standard group.
In group 4 same chemical but only time duration is different so this
sample shown scouring effect is not good, absorbency is also poor
then the group 3. Here bleaching effect shown good.may be this
temperature is suitable for good bleaching in this chemical.
Group 5, here main chemical are not used here only detergent &
wetting agent are used.For better scouring & bleaching effect need to
remove fat , wax & natural gray colore ,So for removing this
impurities strong alkali & bleaching agent (NaOH & H₂O₂) is need .
high temperature to reduce the PH of water .High temperature &
some chemical done some scouring & bleaching here.
Group 6 is similar to the group 5 but here only time duration is
diferent.Here time 20 minute less then the group 5. So here average
all result are poor then the group 6.
In next 6 group, here chemical are used only high temperature &
different duration is used for scouring & bleaching.So here drop test &
other tested result is very poor then the standard group.
In last six group known that only high temperature apply then some
scouring & bleaching have done.Becaus in high temperature,the PH
of water is become less then <7 . So it is gone to acid form.In this
situation for the reason of water acidity form some scouring &
bleaching has been done .
In group 10 all result are passed , but whiteness test is failed.This
reason here bleaching effect is poor.May be here after treatment & in
scouraing & bleaching time & temperature problematic.May be here
temperature can not control perfectly.
Finally after finish this experiment we known that without chemical
also can be done scouring & bleaching.When need deep shade then
good scouring & bleaching effect not mandatory then can be done
this process. Here chemical & processing cost can be reduced.
Conclusion:
The cotton pretreatment, which include scouring and bleaching, can be
completed without the use of chemicals. The two main factors determining
whether textile dyed cloth is accepted on the international market are color
difference, or CMC DE. The combined CMC DE conclusion showed
acceptable values for all 1% colored samples using the chemical-free
preparation. In addition, the colorfastness qualities met expectations, with
evaluations of virtually universally 4/5. This novel method would allow for
the reduction of lengthy washing cycles as well as the elimination of
procedures like peroxide killing and neutralizing, which would both
conserve energy and protect the environment. Finally, this strategy appears
to be quite effective.
