OLISTOP OGD - Novel dispersing agent for oligomers
An oligomer consists of a few monomer units (between 10 to 30 units) in contrast to a polymer that, at least in principle, consists of an unlimited number of monomers. Dimers, trimers and tetramers are oligomers.
The name "oligomers" is made up of oligos, Greek for "a few" and the suffix -mer meros, Greek for "unit, part".
Origin of oligomers
Oligomers are unavoidable chemical byproducts which are formed during the synthesis of fibre polymers (e.g. polyester). Temperature intense process steps during the production of the fiber material, like the granulation and the spinning process, are the reason for the development of oligomers . A standard polyester material can contain between 1 - 4 % by mass oligomers. Mainly in trimer-form, cyclic tris (ethylene terephthalate).
Technical problems caused by oligomers
Polyester fiber materials are usually dyed under high temperature conditions (between 120 - 135 °C). At this temperatures polyester oligomers cause various technical troubles by eluting form the polyester fibre material onto the fibre surface or into the dye bath.
This fact causes following technical issues during the dyeing process and further downstream processes like spinning, winding and twisting:
- Negative influence of the dyeing (e.g. spots, unlevelness, shade, fastness, brilliancy)
- Filtration of oligomers during yarn- or loose material dyeing
- Reduction of liquor-flow in e.g. yarn dyeing, blocking of dye spindle perforations, depositions on pumps (causing pump pressure reduction)
- Soiling of yarn-package carrier and yarn dyeing machinery through depositions of oligomers
- Oligomer dust creation (white powder deposits, dulling of yarn or fabric)
- Negative influence to running properties during spinning and winding
- Machine guides deposits during winding and twisting causing high tensions and increased friction of the yarn (poor package build, frequent end breaks)
- Necessity of frequent machine cleaning causing increased down time and lower efficiency
The solution - OLISTOP OGD Special dispersing agent for oligomers occurring with PES dyeings in the acidic range
OLISTOP OGD is a dispersing agent specially adjusted to oligomers. Due to its chemical structure OLISTOP OGD prevents uncontrolled aggregation and thereby the deposition of oligomers on fibre material and machine parts. Furthermore the product disturbs the crystal growth of the oligomers which results in a formation of very small and dispersed oligomer crystals. The fine dispersion of the oligomers improves the penetration of the liquor into the goods and thereby it improves the levelness. Reduction of the deposition of oligomers leads to better running properties of loose stock fibres, tops and yarns in further processing steps. Cleaning processes to remove oligomers can be saved.
OLISTOP OGD does not influence the dyestuffs or the fibre surface and therefore no changes of the level of fastness have to be feared.
Below pictures demonstrate a few advantages of OLISTOP OGD:
Picture 1: yarn winding process after dyeing
Picture 2: Soiled yarn package carrier after dyeing
Picture 3: Microscopic picture of Polyester yarn dyeing
The application of OLISTOP OGD:
The application amounts depend on the quality of the used polyester.To remove oligomers and soil completely it is absolutely necessary to preclean the equipment with following recipe:
|3.0 - 4.0 ||g/l ||Tecoclean FTK |
|8.0 -15.0 ||ml/l ||NaOH 38° Bé |
|1.0 - 3.0 ||g/l ||Tecoredukt 1000 or TECOREDUKT SRM 235% |
|clean 30 - 60 min at 130°C, drain hot, rinse hot |
For polyester exhaust dyeing OLISTOP OGD is added directly into the dyebath. Following dyeing recipe is recommended:
|0.8 ||g/l ||ALVIRON PWE |
|0.8 ||g/l ||ALVIRON GBU |
|1.0 - 3.0 ||g/l ||OLISTOP OGD |
|0.3 ||g/l ||TC-ÕKOSTABIL BKL |
|x ||% ||TECOCET dyes |
|30 - 60 min at 130°C, HT-drop, no intermediate rinse |
To boost the effect it is recommended to use OLISTOP OGD additionally in the reductive clearing process.Reductive clearing recipe:
|1.0 - 2.0 ||g/l ||Olistop OGD |
|0.3 - 0.8 ||g/l ||Tecoredukt 1000 or TECOREDUKT SRM 235% or |
|2.0 - 5.0 ||g/l ||Hydrosulphite |
|3.0 - 5.0 ||ml/l ||Caustic soda 38° Bé |
|15 min at 80°C, drop bath, neutralisation with 1,0 ml/l acetic acid 60 %, drop bath, 5 min overflow rinse cold |