Thread Science: Choosing The Right Thread From Fiber to Finishing

Thread is a key component of many items that we use daily. From apparel that we wear, to the furniture we sit on, thread is all around us. It is even part of the tea bag used at lunch. Sewing threads are generally used to assemble sewn products together, and the quality of the seam is dependent on the quality of the sewing thread used.

Remember: Thread only makes up a small percent of the cost of the sewn product, but shares 50% of the responsibility of the seam.

A&E manufactures quality threads from many different fiber types, thread constructions, sizes, and colors to meet the demands of the markets they are used in. Each market may require a thread with different physical properties to achieve optimum sewing and seaming performance. If you consider the many uses of thread, the complexity of designing a thread is apparent. Consideration must be given to: sewability, seam performance, seam appearance, not to mention availability and cost. Physical characteristics that vary from fiber type and thread construction include: tenacity, loop strength, linear strength, elongation, elastic recovery, loop formation, twist construction, ply security, shrinkage, stitch appearance, colorfastness, resistance to abrasion, chemicals, heat, and light. Therefore using the proper thread for an application will determine the overall quality of your sewn products.

Selecting the proper thread for your product is achieved by first determining the end-use requirements of your sewn products including: seam strength requirements, stitch & seam design, optimum stitch length, and the normal life of the product. Other factors that are considered include the type of material being sewn, the type of sewing machines being used, conditions under which the product must perform, and cost effectiveness.

Where Do Fibers Come From?

Fibers used to make industrial sewing threads come from two major sources:

Natural Fibers- Come from plants or animals and are spun or twisted into yarns. Cotton is the most common natural fiber used to make thread. Other natural fibers include rayon, Lyocel®, silk, wool, jute, ramie, hemp, and linen. Natural fibers are generally not as uniform as synthetic fibers and are affected by climatic changes. We select our cotton fibers from the best available crops, classifying them depending on the geographic location, climate, plant seed type, and the cotton grower’s reputation. The two classes of cotton fibers that we use include SAK (or Supima) cotton and CP (or Peeler) cotton. SAK is generally a higher quality cotton that produces stronger spun cotton threads than CP fibers.

Synthetic Fibers- Are made from various chemicals that are then melt-spun or wet-spun into a continuous filament fibers. We select our synthetic fibers based on their sewability characteristics, seam performance, ease of dying, colorfastness, pricing and sustainability. The most common synthetic fibers used by A&E’s customers include Polyester and Nylon. Other specialty synthetic fibers include polypropylene, aramids including Kevlar® & Nomex®, PPS, and PTFE.

(DuPont™, Kevlar®, and Nomex® are registered Trademarks of E.I. du Pont de Nemours and Company and are used under license to A&E®.)

Fibers Forms- Sewing threads are made in seven different thread constructions using either staple fibers, continuous filament fibers, or a combination of both. Staple fibers are spun into a specific yarn (cotton count – ex. 29/1) and then plied into a sewing thread (cotton count – ex. 29/2 or 29/3).

Continuous Filaments are used in the manufacturing of five thread constructions including: twisted multifilament, monocord, textured, air entangled and monofilament. Continuous filaments are normally sized using the denier system. Threads made from continuous filaments are generally stronger and have greater uniformity than threads made from staple fibers.

Corespun threads are made from a continuous filament bundle of fibers that are then wrapped with a staple wrapper.

Thread Construction

A&E makes sewing thread in the following seven thread constructions.

Spun Threads – are made from staple fibers that are spun into single yarns and then two or more of these yarns are plied to make a sewing thread. Spun threads have a fibrous surface giving them a soft hand and good lubricity characteristics. Spun threads are used in everything from women’s lingerie to heavy leather gloves. A&E Brands include: Anecot®, Anecot Plus®, Endurance®, Excell®, Flame-Out® SP, Kevlar®, Nomex® & Perma Spun®.

Core Threads – are made by spinning a staple wrapper of cotton or polyester around a continuous filament of polyester fibers. Afterwards, two or more of these single yarns are twisted together to form the thread. Core threads have a fibrous surface giving them good lubricity characteristics and also a continuous filament core that contributes to high strength and durability. When wrapped with a cotton wrap, core threads have very good needle heat resistance. When wrapped with a polyester wrap, core threads have excellent chemical resistance and colorfastness. Core threads are used in everything from fine blouses to heavy coveralls and overalls. A&E Brands include: Perma Core®, Perma Core® Ultimate, D-Core®, and Design-A-Core™.

Textured Threads – are made from continuous filaments of polyester or nylon that have been textured and then heat set to insure proper bulk-retention. Textured threads are ideal for overedge, chainstitch, and coverstitch operations offering a soft seam and good seam elasticity and coverage. Textured threads are generally less expensive than other thread constructions of the same size. A&E Brands include: Wildcat Plus®, Best Stretch®, IntimaSoft®, and Tex Kool®.

Air-entangled Threads – are made from continuous filaments of polyester that are entangled as they pass through a high pressure air jet. This yarn is then twisted, dyed, and wound on cones with lubricant. Air entangled threads are used in everything from quilting mattresses to sewing heavy denim jeans. A&E Brands include: Magic®, Magic HP® , Signature®, and Signature® Plus.

Monofilament Threads – are made from single continuous filaments of nylon that resemble fishing line. Monofilament threads are translucent and blend in with many colors. Because it has a tendency to be stiffer than other filament products, monofilament threads are not recommended for seams that may lay adjacent to the skin. Monofilament threads are used in quilting operations on quilts and bedspreads, as well as blindstitch operations on drapery and apparel. A&E Brand include: Clearlon®.

Twisted Multifilament Threads – are made from continuous filaments of polyester or nylon that are twisted together into a cohesive bundle and then plied to make the thread. They are then dyed, stretched, and heat set to achieve the desired physical characteristics. Twisted Multifilament threads are available either soft or with an additional bond for better ply security and abrasion resistance. They are exceptionally strong for their size and have excellent abrasion resistance and durability. These threads are used for seaming everything from boat sails to automobile upholstery. A&E Brands include: Anefil® and Anefil® DRY. This construction is also used in the manufacturing of RA embroidery brands including Super Brite® Polyester, Super Strength® Rayon, and Twister Tweed®.

Monocord Threads – are made from continuous filaments of polyester or nylon that have been bonded together. They have very little twist so that they look like a single cord of yarn. Because of the way these threads are made, they appear to be flat and ribbon-like, which provides a low-seam profile and therefore a high degree of resistance to abrasion. Monocord threads are exceptionally strong for their size and are used in the manufacturing of furniture, shoes, and other heavy duty applications. A&E Brands include: Anecord®, Anequilt® , Teryl B®, and Signature® Plus.

Thread Dyeing

After the thread yarn is manufactured, it is wound on dye tubes so it can proceed to one of A&E’s many global dye houses for dyeing. Most of our threads are dyed in package dye machines under pressure.

Different fiber types are dyed with different dye types and temperatures to achieve the desired shade and color fastness requirements.

Polyester threads- Normally dyed with Disperse Dyes at high temperatures (265° F / 129° C) using high energy dyes to ensure good colorfastness.

Nylon threads- Normally dyed with Acid or Chromatic dyes to achieve the desired shade.

Natural fibers including cotton and rayon- Can be dyed with either Vat, Fiber Reactive, or Direct dyes depending on the color fastness requirements and the color shade to be achieved. Generally Vat dyed natural fibers have the best color fastness characteristics.

To ensure uniformity in shade reproduction around the world, A&E uses the same fibers, dyes, chemicals and formulas.

As part of our Eco-Driven sustainability program, we do not use any restricted substances listed on the AAFA Restricted Substance list. We have set goals to reduce both energy and water consumption and we have award winning water purification systems.

Thread Finishing

Thread finish can have several meanings in the thread industry. Finishing can refer to any additional process that a thread goes through to alter its original physical characteristics. Examples would include mercerized, glazed, bonded and anti-wick finishes. Finish can also refer to the lubrication put on the thread prior to winding for the purpose of protecting the thread against needle heat and giving the thread good lubricity characteristics as it passes through the sewing machine.

“Soft” spun cotton threads are converted to “Mercerized” threads when they are passed through an additional process where they are treated in a caustic solution under controlled tension. This process causes the fibers to swell, resulting in greater affinity for dye penetration. Mercerization increases the luster of cotton threads and at the same time increases their strength.

“Soft” spun cotton threads can also be converted to “Glazed” threads by coating the threads with starches, waxes, and special chemicals under controlled heat and then brushing or polishing them to a high luster. The result is a glossy, hard finish that protects the thread from abrasion and enhances its ply security.

“Bonded” finish is an additional process performed on multifilament polyester and nylon threads where a special resin is added that encapsulates the filaments forming a tough, smooth protective coating on the surface of the thread. This bonding process adds significantly to the thread’s ability to resist abrasion and greatly enhances ply security during sewing.

“Anti-wick” finish is an additional process where “soft” threads are treated with special anti-wick chemicals to enhance the threads resistance to water migration.

Thread finish or lubricant is generally added to the thread during the final winding process. Both the amount and type of lube are critical to proper sewability. Generally, the finer the thread size, the less lube that is required on the thread. Threads required to penetrate heavier and more dense fabrics will require more thread lubricant to product the thread from needle head and enhance sewing performance.