Elastomeric Silicone Emulsions

Elastomeric silicones are emulsions that cross-link on the fabric to form an elastic film. What separates them from a conventional softener is that they add recovery alongside softness: a stretched knit comes back closer to where it started.

How does an elastomeric silicone differ from a conventional one?

A conventional amino silicone anchors to the fibre and stays there, each droplet on its own. An elastomeric silicone cross-links with itself during drying and condensation. What forms on the cloth is a continuous, stretchable film rather than separate droplets.

The difference is easy to feel. Cloth finished with a conventional silicone is slippery and fluid. Cloth finished with an elastomeric silicone has a full, slightly spongy handle with recovery in it; squeeze it and it opens out faster.

Where does the elasticity come from?

Because the film is continuous, it stretches with the fabric and returns to length when the tension goes. The fabric moves inside that film, which makes it easier for the loops to settle back after being pulled. On knits the visible counterpart is dimensional stability: bagging at knees and elbows falls back, and width loss stays under control.

The film only does this job if it is properly cured. Where curing is short, the cross-links do not form and the product behaves like an ordinary softener. Curing conditions for Derin Kimya products are given on the product pages: pending from the client.

Where is it worth using?

Elastane knits, swimwear, leggings and sportswear come first, because recovery is a measured line in those specifications. On towelling and bathrobes an elastomeric silicone is used for fullness and bulk. On cotton wovens it is chosen for better recovery from creasing.

The question to settle is what the buyer is judging: slip, or recovery and bulk. Where slip is the requirement, a macro silicone is the more direct answer.

How is the effect measured?

An elastomeric finish is judged on measured performance rather than on handle. On knits three figures are used: permanent extension after stretching, dimensional change after washing, and width loss under repeated stretch. Both the method and the acceptance limit come from the customer specification.

In a swatch trial, holding the dosage and stepping stenter temperature and time shows the contribution of the cure directly. That is the practical way to fit the recipe to the mill's own stenter.

Two complaints that come up often

The first is cloth that feels stiff after finishing. Usually the dosage or the cure has been overdone; as the film thickens the handle stops being spongy and turns boardy.

The second is liquor that goes cloudy mid-shift and leaves deposits in the trough. That normally traces back to a made-up bath standing too long, or to an incompatible auxiliary sharing the trough.

What to watch in the bath and in store

Elastomeric products carry reactive groups. That means a made-up liquor has a limited life; a liquor left standing can gel and leave deposits in the pad trough. The trough is drained and washed at the end of the shift.

Compatibility with cationic or anionic auxiliaries in the same bath is trialled beforehand. Concentrates are never poured into one another; each is diluted separately and fed in turn under agitation.

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