Textile Compressive Shrinkage

Compressive Shrinkage is a process in which fabric is caused to shrink in length by compression.It often referred to as controlled compresssive shrinkage.The purpose of the compressive shrinkae process is to shrink fabrics in such a way that textiles made up of these fabrics do not shrink during washing--ALIDO textile finishing machine.

The Sanfor-Set process is a further development in which the preliminary mercerising treatment takes place in liquid ammonia. In principle the fabric is only able to shrink if the hydrogen bonds in cotton are first substantially broken by humidification and steaming. This is brought about by mechanically stuffing the fabric together before the new state is set by drying (locking the hydrogen bonds in place).

The fabric entry to the felt belt  shrinking unit is formed by the sandwich created by a large heated cylinder and a continuous felt belt (21 mm thickness, 40° Shore hardness). The fabric is placed on the extended surface of the felt belt and is thus forcibly contracted by the shortening of the surface of the felt belt, with the smooth surface of the cylinder presenting virtually no impediment to this process. The greater the contact pressure of the felt belt the greater the shrinkage. At the entry point the felt belt can be compressed at most down to 30% of its normal thickness. The corresponding Sanfor-Knit process is used for tubular knitted fabrics and also for open-width flat knits.

The “NY35” tubetex compacting machine , used to shrink tubular knits, operates in a similar way to a rotary press. In the Tube-Tex-Compactor the fabric is passed over a roller running at higher speed and into the gap it forms with the hot shoe. Because the take-off roller, which has deeply engraved lateral surface grooves,runs more slowly the fabric is shrunk in the highly condensed core zone as a result of having been steamed in a twin-jet chamber before entering.

From ALIDO--Textile Finishing Machinery