Sewing Thread

 

Different types of sewing thread, thread finish, thread size, sewing thread package  etc.

What is sewing thread?

Sewing thread is a flexible, small diameter yarn or strand usually treated with a surface coating, lubricant or both, intended to be used to stitch one or more pieces of material.

It may be defined as smooth, evenly spun, hard-twisted ply yarn, treated by a special finishing process to make it resistant to stresses in its passage through the eye of a needle and through material involved in. 

Required properties of a sewing thread

Sewing thread should have following properties

• Uniform: Needle thread must pass freely through the small eye of the needle; consequently, they must be uniform, knot-free, non-torque and fault free.
•  Strength: The strength of the sewing thread must be higher than that of the fabric so that the thread does not rupture during use.
•  Extensibility: Moderate to low extension-at-break of the thread is usually preferred.
•  Elasticity: The elasticity of the sewing thread must be uniform along its length in order to enable equal length stitches to be formed, and it must closely match the elasticity of the fabric being sewn
•  Frictional Properties: The forces that are developed in the sewing thread are mostly due to the friction between the thread and machine parts.The frictional properties are affected by lubrication. Special finishes like silicone compounds have been found to exhibit clear advantage over standard paraffin wax.
•   Abrasion Resistance: The thread must be resilient enough to return to shape after the distortions.Nylon and polyester offer the best resistance to abrasion.
•  Resistance to Heat: The needle temperature is especially critical for fabrics and sewing threads of thermoplastic fibers, where it may exceed their melting temperature.  Lubrication of sewing thread with a mixture of wax, emulsions with synthetic resins, and silicon-based products may minimize heat generation
•  Hairiness: The hairiness of sewing thread also affects the appearance of the seam. Sewing threads for decorative seams are singed and gloss-brushed.
•  Twist Direction: The final direction of twist may be important to stitch formation mechanism. Most sewing machine require Z twist, but there are a few where performance is better with S twist.
•  Color Fastness: It is important that the selected shade retain its color throughout the life of the garment. Two aspects of fastness are important
  
  • The thread must not change color.
  • The thread must not stain any material adjacent to the seam
• Shrinkage: Low shrinkage during washing is required.
•  Luster: Good luster in the thread improves appearance of the seam.
•  Uniform Dyeing: Threads must be uniformly dyed in a good match to the materials being sewn
•  Sew ability: The ability of the thread to perform efficiently in the sewing machine is defined sew ability.It can be assessed by the number of breaks that occur during the sewing of a certain number of stitches. However, owing to the generation of needle heat in high-speed sewing, the threads could be damaged without breaking. The long knot-free evener yarns can give better sew ability. 
• Characteristics: The characteristics of properly constructed seam are strength, elasticity, durability, stability, comfort and appearance.Characteristics of sewing thread should be acceptable.
•  Seam Pucker: Seam pucker can be defined as a differential shrinkage occurring along the line of a seam and is mainly caused due to seam instability, due to high tension imposed during sewing. Sewing thread should not be the cause of seam pucker.

Classification of sewing thread

According to Fibre type:

Natural:

•  Linen.
•  Silk.
•  Cotton.
•  Viscose

Synthetic:

• Polyester.
• Nylon thread.
• Aramid.
• PTFE.

According to Construction:

•  Mono filament.
•  Multi filament.