What alkali reduction does
Polyester is treated with strong alkali. The alkali etches the fiber surface, and the fabric loses a controlled part of its weight. The cloth becomes softer and drapes better, and it feels like silk.
It is a process for polyester and polyester-rich fabric. Do not use it on cotton or cellulosic fabric: the alkali would damage them.
The Runda machine
It is a horizontal, square overflow-jet machine that works at atmospheric pressure. It combines bleaching and alkali reduction in one machine. A new circulating pump design is used, and control can be semi-automatic or fully automatic by computer.
Technical data
| Item | Value |
|---|---|
| Type | Horizontal square, overflow jet |
| Cloth speed | 50 to 200 m/min |
| Nozzle pressure | 0.08 to 0.12 MPa |
| Fabric weight range | 50 to 500 g/m² |
| Fabric capacity | 500 to 1,200 kg |
| Weight reduction | 10 to 25% in 1.5 to 2 hours |
| Max. working temperature | 98 °C |
| Heating | Indirect steam via heat exchanger |
| Main pump power | 18.5 to 30 kW |
| Control | Semi-automatic or fully automatic, by computer |
Figures are the published data of the Runda machine. Options and capacity are set per order.
How to choose
Set the weight reduction target. A higher percentage gives a softer handle but weaker cloth. 10 to 25% is the working range of this machine.
Give the fabric weight and the batch size so that we match the capacity.
Choose the control level. Repeatable weight loss from batch to batch depends on accurate dosing and time control.
Plan the caustic handling and wastewater. Alkali reduction produces strongly alkaline effluent with dissolved polyester oligomers. Your effluent plant must be able to treat it.
Frequently asked questions
Which fabrics can be treated?
Polyester and polyester-rich fabrics, from light chiffon to heavier weights up to 500 g/m².
Why does the machine also bleach?
Bleaching and alkali reduction are combined in one atmospheric machine to shorten the process chain for small lots.
What do I send for a quote?
Fabric type and weight, batch size in kg, weight reduction target, steam pressure, and destination country.
