Necessary Production Operations For A Good Elastane Mixed Fabric
Necessary Production Operations For A Good Elastane Mixed Fabric
- Keeplowtensionin knittingmachines
- Fabricshould be wrappedwith undervoltage
- The fabricshould be wrappedin rolls without wrinkles,
- Fabricrollsshould not be storedontoone anotheras dense
- should not be storedinstoragetooccur fracture trail
- should not be storedfor more than twomonths on sameform.
- Attention should be paidto the choice ofoilto be usedknitting machines
- For threatagainstyellowing, thermofix on hightemperatureshould be avoided.
Considerations on the Use of Elastane
Ask elastane from vendor according to the yarn type you want to use. Before using the elastane yarn please superficial control every party you received (coils, incomplete kg, right denier of all incoming parcels?) Otherwise return the yarn before using elastane where you bought.
Check the lot number of each party of the elastane yarn you bought. Because differences on lots of elastane yarn can cause problems in painting (abraj, flexibility difference. etc. may cause such error)
Because of Elastane production technology is very sensitive, so the elastane threads is itself sensitive. When using knitting machines, operation of each apparatus of the elastane yarn passes must be complete. Especially, there should be no obstacle that could cause tension. Pulleys in contact with elastane, must be on revolving condition. On the mouth of shuttle there must be no flying debris.
Settings Required To Obtain Quality on Fabric
Settings between shooting on circular knitting machines and yarn feed system is the major factor to obtain the quality of the fabric texture (weight, thickness, etc.) and determining the touch. In the absence of this mechanism in the machine there would not have been proper knitting. Knitting, can be collected on pins, after a period stitch will not occur and needles can be broken. Because, to have comfortable work of the needle, the fabric must be taken down in a certain tension. Also this tension must be equal on all surface of the fabric.
When wefirststart buildingfabric; Othersettingsof the machine, may set, the band adjustment,afteradjustmentfor tension, shooting setting must be done to attainthe desiredweightof the fabric.
Importance of Cleaning the knitting machine
During knitting operations, particularly natural fiber yarns, fiber fly, dust and dirt, that mixed with oil and abraded metal particles are make dirt in various parts of the needle and in roller bearing. Over time, this mixture is become compact and tightly bound to place where they are. Increasing an impurity in this manner causes a narrowing of the width of the needle bed of the channel and increases the friction. Needles are slowing, the rise outward from the needle bearings and contact to the various regions of steels. Due to pollution:
Becomes excessive friction, needle and machine gets wear, needles will be damaged, high machine temperatures will occur, would be excessive energy consumption.
Reason of break of elastomer material on Knit Fabric
There are 3 reasons:
Elastomer material, the finishing process (especially heat treatment) and the knitting elements of the knitting machine are making the damages.
Sourced elastomer material breaks, the first of the above reasons, are due to as the industry’s term “stale lycra” that had been subjected to improper storage conditions, or that are the second, third quality elastomer materials. During the knitting process when manufacturing with elastomer material of this type, by the given pre-tensions on material there will be break as a result property lost of the material. But the appearance of the rupture zone will not have sharp surface. Additionally, this rupture will be noticed by the thread control device in the knitting machine and the machine will be stop and the knitting of broken material will be prevented. Thus, complete rupture of the elastomer material in the fabric structure must be realized after yarns are receiving the loop form, not during the knitting process.
This type of error is not possible as result of thermal treatment (such as drying). Because view of the thermal damage of the elastomer material will occur in the form of shrinkage of the fiber end and absence of the view in this way, the error is not reason by heat.
Another reason for the elastomer rupture error; The worn planes of knitting elements of the knitting machine (needle, platinum), being as like a cutting tool, by giving damage to elastomer material completely and/or partially ruptures on large portions and on later stages by the tensions applied to the knitted fabric (open and wrap the fabric, drying the paint shop … etc.) rupture on rest of fabric is likely to emerge.
Dyeing and Finishing of Circular Knitting Fabrics with Elastane Yarn
On finishing and dyeing of knitted fabrics with elastane yarn, final dimensional stability and curling feature of the fabric is important to obtain. Sequence and number of finishing depends on various factors and the most important of these factors are;
The type of fiber used, the machine selection and the cost of dyeing.
- Flotte ratio: compared to 100% cotton working, 20% -30% should be increased.
- Because of fabric comprising elastane is 25% heavier than equivalent amount of 100% cotton fabric, on loading machine rope length of the fabric must be reduced.
- Bath should not be cooled on shock.
Considerations During the Dyeing of Fabric Containing Elastane Yarn
Do not use Azoik Dyes (have the effect of lowering the quality of the elastane threads). Do not use water that contains chlorine. Use dyes and auxiliaries that are less polluting elastane yarn. Use dyes and auxiliaries that have good wash fastness. Determine the properties of elastane yarn and use dyes and auxiliaries according to that., For the type of elastane yarn to determine the conditions that have the best results on dyeing, make Experiments in the laboratory.
Considerations During Working on Fabrics with Lycra
If Knitted fabrics will be hold, should be washed and dried if possible, should be wrapped around the reel without creating internal fractures.
Fabrics hold on depot, if possible not stacked overlap, must be put on fabric cases. On cases date of set of fabrics mut be noted, and fabrics should be used by this date notes.
Held fabrics mut be covered by black colored fabric.
Depot time should not exceed two months time.
Considerations on Pre-Fixing of Fabrics with Lycra
The desired width, weight and structure of the fabric
The type of clothes to be made
Which color will be dyed
Type of Lycra
Ratio of Lycra
Heat sensitivity of the fibers
Impact against time and temperature of heat setting on the fabric
| FEATURE | HEAT RAISE | TIME RAISE |
| Stability | Increases | Increases |
| Shrinkage | Decreases | Decreases |
| Whiteness | Decreases | Decreases |
| Tidiness | Increases | Increases |
| Power | Decreases | Decreases |
| Width | Increases | Increases |
| Oil Stains | Increases | Ineffective |
| Egalizes | Decreases | Ineffective |
Pre-Fixing of Fabrics with Lycra
There are benefits of using of wetting and degreaser in terms of quality on pre-fixing.
The Fabric shoud be stay 1 minute on Stenter. (on 8 cabins ram 18 m/min)
First, on 1 roll fabric, fixing should be done 10 g/m² more than desired finished weight, that will give tensile test. In the tensile test weight ,after washing, must be 15-20 g/m² more than desired weight. Once these conditions are met fixing process should be continued. If the weight is less or more we will decrease or increase fixing speed.
Studying the Viscose Lycra Fabric
On these fabrics, unlike the fixing fabrics with lycra, I advise drying with water on ram before. After that fixing prodecure must begin. On fixing procedure adding wetting agent and degreaser will be useful. On pre-fix we have to work fabric on maximum feeding. Before cutting finished fixed fabrics with lycra, by passing fabric from the steaming machine called S-TEKS, we can give stability on every part of fabric. I advise this to all Confection Firms.
Ekrem Hayri Peker
Chemical Engineer
