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Why post dye garments?
Where similar
garment styles need to be produced in a range of
fashion colours with short lead times, it is
logistically simpler to dye at garment stage
(thread, trimmings and fabric together) rather
than use dyed fabrics.
What are the limitations
of post dyeing?
-
Post dyeing is not suited to all fabrics.
-
Does not always provide the desired final
appearance in the garment.
-
The sewing conditions required to produce cotton
post dyed garments may result in imperfect
seams.
-
There is a high risk of inappropriate thread
use.
-
There can be no guarantees of absolute
compatibility between thread and garment even in
apparently ideal situations.
Which sewing threads to use for post dyed
garments?
-
Thread should be
selected on the basis of the fibre composition of
the fabric.
|
i.e.100%
cotton fabric |
- |
100%
cotton threads |
|
100% nylon
fabric |
- |
100%
nylon threads |
|
|
-
100% cotton threads
are coarse for their strength and have relatively
low elongation, therefore they need relatively
light sewing tension and high stitch densities.
-
The thread finish
should be selected to align with the fabric
finish.
|
For unbleached
fabrics |
- |
Unbleached
thread |
|
For partially
bleached /scoured fabrics |
- |
Half
bleached thread |
|
For fabrics
which are bleached white prior to make-up |
- |
White thread |
|
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- Ensure that
the thread has no tinting agent
What
about machine settings?
- Sewing speeds
should normally be set lower for natural thread
products compared to those used for synthetic
threads.
- Unlike
synthetic sewing threads, sewing with 100%
cotton threads requires machine sewing elements
to be maintained in pristine condition.
- Large size
needles to accommodate coarser thread may
necessitate changes to settings.
- Hook, looper
and feed timings may need adjustment.
General sewing guide
|
Tkt |
Tex |
Total Decitex |
Ply |
Average
Strength+ cN |
Recommended
needle size*
Singer/Metric |
|
60 |
30 |
300 |
3 |
830 |
11-12 / 75-80 |
|
50 |
35 |
375 |
3 |
1030 |
12-14 / 80-90 |
|
40 |
40 |
460 |
3 |
1235 |
14-18 / 90-110 |
|
30 |
60 |
660 |
3 |
1910 |
18-19 / 110-120 |
|
24 |
80 |
750 |
3 |
2060 |
18-20 / 110-130 |
|
08 |
240 |
2400 |
9 |
5780 |
Gimp** |
|
+ |
Average Strength
shown is for mercerised products. Soft
products will have approx. 5% lower strength. |
|
* |
Needle size
recommendations are a guide only and
ultimately depend on the sewing application. |
|
** Gimp: |
A thick thread
used to support and raise the buttonhole
stitching. |
Physical and chemical properties of cotton thread
 |
Acids |
: |
Sensitive to
mineral & organic acids especially if
halogenated. |
|
|
Alkalis |
: |
Swells in
Caustic mercerising but is not damaged. |
|
|
Organic
solvents |
: |
Generally
unaffected by most organic solvents.
Generally unaffected by sodium hypochlorite,
sodium perborate and peroxide bleaches under
controlled conditions. There is a
probability of strength loss if contaminated
with iron during bleaching. |
|
|
Insects / and
Micro organisms
(Mildew rot) |
: |
Resistant to
ageing and moth attacks but sensitive to
mildew growth. |
|
|
Moisture
regain |
: |
Approximately
8% |
|
|
Laundering |
: |
Good
durability. Shrinkage at 100°C typically 1 %
or less.
Sensitive to temperatures greater than 130°C |
|
|
Heat |
: |
Burns readily,
decomposes at 160°C.
Prolonged exposure to sunlight causes
yellowing and strength loss. |
|
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Finishes |
: |
The lubricants
applied are designed to give a consistent
performance at high sewing speeds and a
minimum variability between shades. |
Coats strongly recommend that sample garments are
dyed and finished before proceeding to bulk
production as the constituents of the fibre are
outside of our control.
Coats can provide on site technical assistance
for sewing post dyed garments.
Please contact your local office.
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