What Is Alkali Reduction & When Do You Need This Machine?
Alkali reduction - also called caustic weight reduction or polyester de-weighting - treats polyester fabric with concentrated alkali to etch the fibre surface. The fabric loses a controlled percentage of weight, becomes softer and more draping, and takes on a silk-like hand feel. An alkali reduction machine is the dedicated equipment for this finishing step.
This automatic liquid-flow machine is a new atmospheric model developed through market research and repeated trials based on advanced products at home and abroad. It combines bleaching and alkali reduction in one machine, mainly for weight reduction of fibres, improving polyester fabric quality and greatly raising the value of the fibre.
You need it when you finish polyester or polyester-blend fabrics for apparel, lining or imitation-silk goods where a soft, drapey, silk-like handle is the selling point. Because it combines bleaching and alkali reduction in one atmospheric unit, it also shortens the process chain - a practical advantage for small-batch, multi-style finishing.
Core Parameters & Technical Data
Type: horizontal square, overflow jet type.
Process: atmospheric, combining bleaching and alkali reduction in one machine; indirect steam heating via heat exchanger, maximum working temperature 98 degC.
Cloth speed: 50-200 m/min.
Nozzle pressure: 0.08-0.12 MPa.
Fabric weight range: 50-500 g.
Fabric capacity: 500-1200 kg.
Working time: 10%-25% weight reduction in 1.5-2 hours.
Main pump power: 18.5-30 kW; new circulating pump design; semi-automatic or fully automatic computer control to user needs.
How to Choose the Right Alkali Reduction Machine
Confirm the process is polyester. Alkali reduction etches polyester fibre; it is not for cotton or cellulose fabrics, which the caustic would damage.
Choose the weight-reduction target. The machine runs a 10%-25% reduction in 1.5-2 hours; your target hand feel sets how much weight you want to lose.
Match fabric weight and batch to the machine. It handles 50-500 g fabric at 500-1200 kg capacity - tell us your goods and lot size.
Pick the control level. Semi-automatic or fully automatic computer control is available; automatic dosing matters for repeatable weight loss from batch to batch.
Check the heating and circulation. Indirect steam heating via heat exchanger and the new circulating pump design keep treatment even and the temperature stable.
Buy from a factory that understands the finishing line, since alkali reduction sits between pre-treatment and dyeing or finishing.
Plan the caustic handling and effluent around the machine. Alkali reduction uses concentrated alkali, so confirm dosing circulation, neutralization and discharge arrangements on your site before ordering.
Common Mistakes Buyers Make
Using it on the wrong fibre. Alkali reduction attacks polyester; on cotton it damages the fabric, so confirm fibre content first.
Over-reduction. Too much weight loss weakens the fabric; stay inside the controlled 10%-25% window by time and process data.
Ignoring dosing and temperature repeatability. Uneven caustic concentration or temperature gives patchy handle and inconsistent weight loss.
Forgetting the bleaching-in-one design. The machine combines bleaching and alkali reduction in one unit; planning around that saves a process step.
Under-sizing or overloading batch capacity. Running tiny lots on a 500-1200 kg machine wastes liquor, while overloading risks uneven treatment.
Why Buy from Wuxi Runda
We are a production factory founded in 2004, located in Qianzhou, Wuxi - inside Jiangsu's dyeing machinery industrial cluster, close to component suppliers and skilled workers.
We cooperate with textile research institutes and technical colleges year-round, and design and develop our own series of dyeing and finishing equipment based on advanced products at home and abroad.
Our machines are built for small-batch, multi-variety, low-energy-consumption production, with reliable and stable finishing performance.
Our equipment is exported to Vietnam, India, Bangladesh, Indonesia, Pakistan, Japan, Thailand and other Southeast Asian markets, backed by complete after-sales service including installation, commissioning, spare parts and training.
Frequently Asked Questions
What is alkali reduction and what is it used for?
Alkali reduction (caustic weight reduction / polyester de-weighting) treats polyester fabric with alkali to etch the fibre surface, turning a hard hand feel into a silk-like softness and raising the value of the fabric.
How much weight is removed and in what time?
The machine achieves a 10%-25% weight reduction in 1.5-2 hours, depending on the target hand feel and fabric; cloth speed ranges 50-200 m/min.
What fabrics can it process?
It is mainly used for weight reduction of polyester fibres and polyester-blend fabrics to improve quality and give a silk-like handle, processing fabric in the 50-500 g range at 500-1200 kg capacity.
Is it an atmospheric or pressure machine?
It is a new atmospheric model, with indirect steam heating via heat exchanger and a maximum working temperature of 98 degC, and it combines bleaching and alkali reduction in one machine.
What control options are available?
It can be supplied with semi-automatic or fully automatic computer control according to your needs, together with a new circulating pump design for uniform treatment.
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Get a Quote for Automatic Liquid-Flow Alkali Reduction Machine
Tell us your fabric type, working width and process requirements. Our engineers will recommend the right configuration and send you a detailed quotation.