Crease marks: why the rope keeps folding in the same place

How does a crease actually form in the machine?

Creasing is mechanics, not chemistry. Fabric runs through a jet or overflow in rope form. A rope is not a straight tube; it folds somewhere on every pass. If the fold lands in a different place each time, nothing shows. If it keeps landing in the same place, that line gets written into the fabric.

Two things have to come together. A fold that repeats, and enough temperature and tension to set it. Without either one there is no crease mark. With both, it is only a matter of cycles.

What keeps the fold landing in the same place is well known. When rope length matches the circulation path of the machine, the pattern locks. An overloaded machine leaves the cloth nowhere to move. Low nozzle pressure drags the rope instead of driving it. As liquor ratio drops, the fabric rides on itself instead of floating. Cloth piling in the storage chamber sits there for minutes holding the same fold line.

So when a creasing complaint arrives, the first question is not which product to add. It is how many kilos are in the machine and how long the rope is.

Creasing rarely arrives alone. A shading difference forms along the same line, and the batch often gets reported as unlevel rather than creased.

Which fabrics sit in the risk group?

Heavy, firm knits come first. Interlock, rib, three-thread fleece and similar constructions are thick, so the fold carries a large bending stress and resists opening again.

Viscose is its own heading. Wet strength is low, the fibre swells and behaves plastically. A fold formed in wet viscose becomes permanent far more readily than one formed in dry cotton. The same reasoning applies to modal and lyocell, to a different degree.

Polyester, and microfibre qualities in particular, is at risk for a different reason, which is the next section. Anything that has been heat set belongs in the same group: a structure that has already been shaped thermally will accept a second thermal shaping just as readily.

Elastane blends qualify because they meet heat and tension together. On satins and dense wovens creasing happens less often, but when it happens it shows more, and on dark shades the shading difference is visible immediately.

There is also rope torque. Knitted fabric twists as it circulates in rope form, a twisted rope tightens, and the fold line sharpens. Machine devices that reduce torque, and the rope length setting itself, belong to the creasing discussion for that reason.

Why will a crease in polyester not wash out?

Below the glass transition temperature, the amorphous regions of polyester are frozen. Above it the chains gain mobility. If the fabric is folded at that temperature and then cools, the chains freeze again in the new position. The fold is now part of the structure.

The literature puts the glass transition of polyester at roughly 70 to 80 °C. That is a class range, not a product specification, and it moves with measurement method and moisture content. What it means on the floor is blunt: disperse dyeing temperatures sit far above that band, so every minute of the dyeing carries the potential to set a crease.

The consequence follows. A crease set that way does not wash out and a softener will not hide it. The only route to opening it is taking the fabric back above the same band and cooling it without the fold, which usually means accepting shade and handle risk.

Cotton and viscose are more forgiving. There the fold is held by rearranged hydrogen bonds and wetting recovers most of it. On cotton that has been given a resin-based easy-care finish, the situation goes back to looking like polyester. On an elastane blend the fold is held by both the polyester and the elastane, which lowers the chance of opening it further still.

Which levers cost nothing?

There is a list to work through before anyone buys an anti-creasing agent. All of it is process, and none of it touches the purchasing budget.

Liquor ratio. The longer the liquor, the more the fabric floats and the less it rides on itself. A short-liquor saving paid for in creased seconds is not a saving.

Loading. The nominal capacity of a machine and the capacity at which it runs without creasing are not the same number. The second one is found by trial per quality and written on the recipe card.

Rope length. The relationship between rope length and the circulation path decides whether the fold repeats in the same place. Take it into account when splitting batches.

Machine speed and nozzle pressure. Keeping the rope moving keeps moving the fold. Drop the speed and the fold starts staying where it is, which nobody sees on a screen.

Heating and, above all, cooling rate. Most creases get set during cooling. Cool fast and you freeze whatever fold happens to be there at that moment.

Pre-wetting. Feeding dry cloth straight into a hot bath produces a stiff rope with no slip on the first passes. Starting by wetting out in cold water lowers the fold risk during those passes.

Unloading temperature. Cloth dropped hot and left in a pile gives back everything the machine gained.

Polymeric or oil-based?

An anti-creasing agent lubricates. It lowers fabric-to-fabric and fabric-to-metal friction so the rope slides instead of folding. There are two routes to that, and they carry different costs.

In the Derin Kimya range, DK ANTICREASE 1026, DK ANTICREASE 1010 and DK ANTICREASE MAX are polymeric, and DK ANTICREASE OB is oil based. Dosage and application conditions depend on the product and the machine: pending from the client.

Two warnings apply to both. First, an anti-creasing agent is a surface-active system and it can affect how the dye reaches the fibre, so do not raise dosage on dark shades without a lab check. Second, lubricant left on the cloth travels into the next finishing step. Plan the washing-off together with the anti-creasing agent, not afterwards.

The choice often ends on how much foam the machine tolerates. Foam disturbs circulation in a high-speed jet, and disturbed circulation raises creasing risk on its own. A badly chosen product can enlarge the problem it was bought to solve.

Chemistry or machine?

An anti-creasing agent does not do what the machine cannot do. It covers the margin the machine leaves behind, and nothing more.

There is a budget side too. The agent is spent again on every batch, while a loading and liquor ratio setting is made once and stays made. When two routes give the same result, that difference usually decides which one gets taken.

First response when creases appear

1. Decide while the cloth is still in the machine. Whether a crease is temporary or set is easiest to tell wet, before the temperature comes down.
2. Drop the temperature, raise the liquor ratio and run the rope freely for a while. A good share of temporary folds open here.
3. If they do not open, find the step where they formed. Heating, hold, cooling and unloading usually separate cleanly, and a shading difference along the edge of the mark is the clue.
4. Do not unload hot. Lowering the unloading temperature alone settles many batches.
5. For set creases the route depends on the fibre. On cotton and viscose, damp open-width drying, a calender or a sanforiser gives a chance. On polyester the fabric has to go through heat again, which brings shade and handle risk with it.
6. Change loading, liquor ratio and speed before the next batch. Running the same settings again is buying the same result again.
7. Record the outcome by quality and by machine. Creasing is the kind of problem that shows a pattern within a few weeks once someone keeps the records.