Yarn and Fabric Properties


Structural differences between rotor-& ring-spun yarns 

  •  It will be recalled that ring-spun yarn contains envelope twist [twisting in the fibres from outside inwards], whereas rotor-spun yarn has core twist [twisting in the fibres from the inside outwards].
  •  Rotor spun yarn is therefore more voluminous, more open & rougher than ring spun yarn.
  • The fibres in the envelope layer of a rotor-spun yarn can partly escape the twisting action   during spinning & therefore take up turns of twist.
  •  They thus contribute relatively little to yarn strength & can more easily be rubbed together axially to form slubs, etc.
  •  Rotor spun yarn generally needs rather more turns of twist than ring spun yarn.
  •  Furthermore, the fibres in a rotor-spun yarn are less parallel than those in a ring-spun yarn.
  •  The core twist structure & the lower degree of parallelism are the causes of lower strength of rotor-spun yarn, & also of most other character differences.
  • The role of the wrapping fibres should also not be overlooked, but it is less important than those roles mentioned above.
  •  The positive characteristics of rotor-spun yarns become more marked the shorter the fibres in the strand.
  • The following sections will set out the most important differences in the characteristics of rotor-& ring-spun yarn [ of carded cotton].

Rotor-spun yarn compared with ring spun yarn


Rotor Spun Yarns Compared With The Ring Spun Yarns

Breaking strength.
Coefficient of variation of strength
Elongation at break.
Often Higher
Mass irregularity [over short lengths] 
Volume Greater
Resistance To Abrasion Better
Stiffness Higher
Handle Harder

Aesthetic Properties

Surface Rougher
Hairiness Lower
Luster Duller

Important Differences In Further Processing

Tendency to form slubs under axial force.
Coefficient Of Friction Higher
Knot (Loop) Strength Lower
Resistance To Abrasion Better
Hairiness Lower
Tendency To Snarl Lower
Work Capacity Under Cyclic Loading Higher
Capacity To Take Up Dye Higher
End Breaks In Warping Lesser By 50%
Knots After Winding Lesser By 15-17 /Kg.
Warp Breaks In Weaving Lesser By 70%
Weft Breaks In Weaving Lesser By 25%

Fabric Properties

Tensile Strength Lesser
Tearing Strength Lesser
Bursting Strength Lesser
Appearance More Uniform
Barring Very Much Better
Cover 10% Better
Cleanliness Better
Neppiness Fewer Neps
Resistance To Abrasion 5-7% Better
Handle Harsher Or Crisper
Thermal Insulation 10-15% Better
Air Permeability 15-25% Better
Absorption Of Water Much Better
Take Up Of Dyes Better
Shrinkage Same
Raisings Easier & Uniformer

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