| The effectiveness of hydrogen-peroxide in bleaching of cellulosic fibres is depended upon the reaction time, high temperature and alkaline pH. Use of elevated temperatures can lead to loss of peroxide due to thermal decomposition, also the fabric strength can be diminished due to the action of free radicals and high pH. High temperature and high pH are affecting also the fastness properties and shades of colours, when bleaching blends of raw cellulose with pre-dyed yarns. It may deteriorate also the physical properties and elasticity of blends of cellulose with sensitive fibres such as Lycra, Tencel, Polyacrylamide, Wool and Viscose.Use of Avco- ACTIVANT LTB in peroxide bleaching enables bleaching at lower temperatures and lower pH.
SPECIFICATION:
| Appearance |
White to light cream powder |
| Chemical nature |
Polyacetylated amino compound. |
| Compatibility |
Is not compatible with concentrated alkalies, acids and strong oxidizing agents. |
| Density |
450 – 550 gr/1000 cc |
| Environment |
Product is biodegradable with low toxicity to fish. |
| Health |
Product is non toxic and non irritant to skin and eyes. |
| pH (20°C) |
7 ± 1 (0.2% solution) |
| Solubility (20°C) |
2% in water (50°c) |
| Storage |
Keep drum tighly closed in dry place. |
FILM PROPERTIES:
- Improving whiteness when bleaching sensitive fibre blends such as Cotton/Lycra.
Tencel/Lycra, Viscose/Lycra and Polyamide/Lycra.
- Lower operating temperatures.
- Lower pH values needed in the bleaching solution.
- Alternative single stage process, compared to two stage hypocholorite/peroxide
bleaching can be used.
- Milder bleaching side effects such as lowering wash fastness of dyestuffs and
diminshing fabric physical properties when bleaching blends of cellulose with
predyed fibres or with sensitive fibres/yarns.
PROPERTIES & USES:
The bleaching effect of hydrogen-peroxide and peroxy-salts can be significantly
enhanced by the use of AVCO-ACTIVANT LTB. The controlled reaction of the product with
peroxides is producing an activated oxydizing system having the following advantages:
- Improving whiteness when bleaching sensitive fibre blends such as Cotton/Lycra.
Tencel/Lycra, Viscose/Lycra and Polyamide/Lycra.
- Lower operating temperatures.
- Lower pH values needed in the bleaching solution.
- Alternative single stage process, compared to two stage hypocholorite/peroxide
bleaching can be used.
- Milder bleaching side effects such as lowering wash fastness of dyestuffs and
diminshing fabric physical properties when bleaching blends of cellulose with
predyed fibres or with sensitive fibres/yarns.
APPLICATION:
Use of AVCO-ACTIVANT LTB in exhaust bleaching proccesses:
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Full bleaching at 50- 60°C of cotton blends with pre-dyed polyamide and polyester.
Use the following recipe:
AVCO-BLANKINOL VLF 3 – 4 g/l
AVCO-ACTIVANT LTB 4 g/l
HYDROGEN PEROXIDE (50%) 8 – 12 cc/l
AVCOLUX CBA-100 0.6 – 0.8 %
Treat at 50-60°C for 1-2 hours. This proccess is replacing the conventional two step proccess based on cold chlorine bleach followed by peroxide bleach at 50-60°C.
-
Half bleaching at 75°C of cotton blends with acrylic fibres.
Use the following recipe:
AVCO-BLANKINOL VLF 2 – 3 g/l
AVCO-ACTIVANT LTB 2 g/l
HYDROGEN PEROXIDE (50%) 3 cc/l
Treat at 75°C for 1 hour.
-
Bleaching at 80-90°C of cotton fabrics at milder pH and lower consumption of peroxide.
Use the following recipe:
AVCO-BIOLUZE GLF 1 g/l
AVCO-STABILIZER HP 0.5 – 1 g/l
AVCO-ACTIVANT LTB 2 g/l
HYDROGEN PEROXIDE (50%) 4 – 6 cc/l
AVCOLUX CBA-100 0.6 – 0.8 %
Treat for 10-15 minutes at 80-90°C at neutral pH.
Add 1-2 gr/l soda ash and continue bleaching at 80-900C in mild alkaline conditions for 30-40 minutes longer.
CONTINUOUS BLEACHING PROCESSES
In hot continuous bleaching and in cold pad batch bleaching proccesses it is possible to lower consumption of peroxide and caustic to average of 40-60% of the original recipe. The result is a significant cost saving. Also there are fewer variations of whiteness degree compare to the conventional recipe. For recipes and procedures, please contact AVCO’s laboratories.
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