What is Sewing Thread? Types and Application

What is Sewing Thread?

Sewing thread is a significant accessory used to combine two or more fabric pieces in a garment. It is a tightly twisted strand of two or more plies of yarn that are circular in form when cut in a cross-section. It may be defined as smooth, evenly spun, ply yarn, treated by a special finishing process to make it resistant to stresses applied in its passage through the eye of a needle and through material involved in seaming and stitching operations.

Sewing threads require functionality for making garments for their intended uses.

Sewing thread forms efficient stitches in the fabric without breaking or being distorted during the product life cycle. Threads and yarns, while having similarities as they are both long, thin strands of material, have distinct differences in their end usage and characteristics. The terms can be used interchangeably; thread can be made of yarn, but yarn is not made of threads. Sewing threads can also add aesthetics to seams and fabric pieces.

What is Sewing Thread Made of?

Definition of sewing thread: Sewing thread gets its strength and characteristics from two main sources: natural fibers and synthetic fibers. Natural fibers, like cotton, linen, silk, or wool, offer breathability and a softer feel but are also less resistant to abrasion or stretching. Synthetic fibers, such as nylon and polyester, acrylic, and viscose rayon, provide superior strength, uniformity, and abrasion resistance, making them suitable for various uses. The choice of thread material ultimately depends on the specific application and desired properties.

Sewing Thread Construction

The two most common manufacturing materials for sewing threads are staple fiber and continuous filament. S-twist and Z-twist are given to make desired sewing threads. Generally, S-twists are inserted for spinning single threads and more than one single thread is assembled together by Z-twist for using sewing threads. Z-twist sewing techniques are commonly used, while sometimes S-twist sewing threads are used in flat lock sewing machines and for some special purposes. 

According to the construction of yarn, sewing threads are following categories-

1. Mono Filament
2. Multi Filament
3. Core Spun Thread
4. Textured Thread
5. Spun Threads
6. Embroidery Threads
7. Technical Threads

Mono Filament:

• This thread is made of one continuous filament.
• Zero twists on the thread.
• High strength and stiffness.
• Seam locking power is less.
• It has a tendency toward slippage and causes discomfort.
• Shade matching is good due to the transparent filament.
• Used in garments such as overcoats, raincoats, etc.

Multi Filament:

• Made from more than one filament by twisting.
• For inserting flexibility in threads, yarns are twisted, set, dyed, and lubricated.
• Very high strength and durability.
• Used in garments or leather goods.
• Low cost.

Core Spun Thread:

• Mainly the combination of continuous filament and staple fibers.
• single yarn is used as center yarn and wound with cotton yarns around the center yarn.
• Polyester filament is used as the core, while cotton fiber is used as the staple.
• The strength of the core-spun thread is impressive compared to synthetic threads.
• Less shrinkage. 
• Thread damage is not noticeable.
• Basically, it is used in some high-quality garments. 

Textured Thread:

• Made from textured yarn.
• Crimp property is inserted in filament by false twisting, air jet, and edge crimping.
• This type of thread feels soft. 
• Basically used as an under-thread and edge stitching.
• Normally, it is used as a looper thread.
• The seam locking power is excellent.

Spun Threads:

• They are generally produced from both natural as well as synthetic fibers.
• Shrinkage is significantly low compared to cotton thread
• Sewing performance is excellent but is less than the strength of continuous filament yarn.
• These are mostly used in shirts, trousers, knitwear, jackets, etc.
• Cotton threads, linen thread, silk thread, spun synthetic-fibre threads, and spun blended sewing threads.

Embroidery Threads:

• Used for decorative purposes. 
• Color and luster are the two crucial requirements for embroidery thread.
• Threads for machine embroidery are usually made of polyester and rayon less often cotton or silk.
• These threads are mostly made from mercerized cotton, silk, viscose rayon, and polyester fiber. 

Technical Threads:

• Specially developed for technical/industrial uses.
• used in adverse climatic conditions, industrial conditions, and also for heavy-duty applications worldwide.
• These are commonly made from aramids, glass, ceramics, etc.

Properties of Sewing Thread

Sewing thread, having such a simple appearance, shows a surprising array of properties that directly have an impact on its functionality and application in garments. The proper thread selection mainly considers the fabric type and desired outcome. By acknowledging these properties of sewing thread, anyone can make choices for successful and long-lasting sewing projects.

Types of Sewing Thread

In terms of sewing, it’s critical to choose the right type of sewing thread that can ensure maximum durability and a professional touch. There are several types of sewing threads available to use for both machine and hand stitching.

Linen Thread: Linen thread is produced from natural linen fibers, which are very strong and are best used with fabrics of heavy weight. The linen sewing thread was generally used at a large rate to sew canvas, heavy-duty bags, upholstery, coarse fabric, and so on. But now synthetic threads have replaced it.

Silk Thread: Silk thread is made from 100% silk, which has wonderful properties. Silk thread is used for closing seams or decorative stitches on a garment. Both continuous filament and broken filament silk are used to make this type of sewing thread. Comparatively, it contains higher strength, a high luster, a smooth surface, and good qualities. Silk sewing thread is very costly. That’s why it is used to sew expensive garments.

Soft Cotton Thread: Cotton thread comes from natural cotton fibers and varies in a few different weights: 12 wt, 50 wt, and 80 wt. Bleaching and dyeing treatments have been applied to this type of sewing thread for end uses, and lubricants are also used to make the thread more friction-resistant.

Mercerized Cotton Thread: The entire fibers in the threads become round in shape and gain higher strength and comparable brightness by finishing treatment with caustic soda solution and maintaining the required tension.

Glazed Cotton Thread: Usually this thread is made by using a surface coating on the soft cotton threads. As a result, the threads become highly stiff and smooth, which also increases the frictional resistance of the thread.

Viscose Thread: Viscose thread is commonly made from both continuous filament and staple fibers. The strength and stability are comparatively weak, but they show excellent brightness. It has limited use as a sewing thread but gives a nice finish to machine embroidery and flat stitches. Besides seams, it has a smooth finish and a slight sheen and is best used for all kinds of decorative sewing.

Polyester Thread (All-Purpose Thread): Polyester thread is widely used in garments among synthetic fiber sewing threads. These sewing threads have significant properties like strength, low cost, good washing fastness, durability, and satisfactory elastic properties. Polyester thread can be washed up to 150°C under some conditions without any shrinkage. It is widely used due to its low cost and availability. Polyester thread is made from fiber that has a specific length of around 2.5–4.75 inches.

Nylon Thread: Hand-sewing applications need nylon thread to be sewn into preferred fabrics. Hexamethylene diamine and adipic acid are the two main components of nylon. Because of its high extensibility, seam puckering after sewing due to shrinkage happens. These types of threads have a variety of uses, like sewing knitted fabric, extending seams, and sewing swimming wear. Due to their resistance to rot from chemicals like cotton thread, thicker nylon threads are used to sew leather apparel.

Aramid Thread: Aramide threads are not produced at a large rate because of their more expensive and sophisticated uses. These threads are used in technical textiles, i.e., firefighting garments, protective suits, medical equipment, etc. It has a high cost. Nomex and Kevlar are two commercial names of aramid fiber used worldwide.

PTFE Thread: The use of PTFE sewing thread is very limited due to the higher cost. These special types of threads are mainly flame-retardant and protect against melting and chemicals in garments.

Basting Thread: Basting thread, or tacking thread, is a lightweight type of thread mainly used for basting stitches. 

Invisible Thread (Monofilament Thread): Invisible thread is a form of nylon thread that has a clear fishing line. It is very thin in shape and is used for hems or seams that require an invisible stitch across the surface of the garments. It can be either machine- or hand-stitched.
Quilting Thread: It is a hand-sewn type of thread and is usually a form of mercerized cotton. Quilting thread is coated with a light waxy finish, allowing suitable movement through quilting layers and also making it easier to hand stitch through layers of fabric without causing any wrinkles. It can’t be used in sewing machines, as the wax finish can cause problems. 

Elastic Thread: Elastic thread is an elasticized thread that is used at the bottom of a sewing machine. It can be used with an all-purpose thread on the top to sew shirring, smocking, or ruffles. Elastic thread is elasticized for sewing rows in the waist or chest area and is usually hand-wound onto a regular-type bobbin.

Topstitching Thread: Topstitching threads usually consist of 3 strands of thread tightly wound together with the yarn axis and have a weight of 30. It also requires a topstitching needle to sew, as the thread is a lot thicker than universal sewing threads. 

Denim Thread: It is a thick and strong sewing thread that is used to topstitch denim pockets, denim jackets, felted seams, zippers, belt loops, or detailing. Most brands have a good selection of denim colors to choose from, and they use these threads in any medium- to heavy-weight denim fabric.

Jeans Thread: Basically, it is a two-tone polyester/cotton blend thread that can adapt to all denim fabrics.

Metallic Thread: Metallic thread has a shiny and glittery look that gives a glistening effect to any material, and it is also used for decorative stitches.

Polyester/Cotton Sewing Thread: It is a multipurpose thread and weighs around 50. It is suitable for all types of fabric, including stretch. One of the most commonly used threads for most of our sewing procedures. 

Heavy Duty Thread Types (Upholstery Thread): When working with canvas or leather, which are heavy upholstery fabrics, it is important to use one type of super-strong thread to ensure maximum durability. A heavy-duty thread’s weight is around 3 wt. These fabrics often experience significant pressure and wear and tear, so a highly strong, tear-resistant, and durable upholstery thread is necessary to maintain their quality. 

Classification of Sewing Threads

There is not a specific classification for sewing thread. However, common sewing thread can be classified in the following ways:

1.  Substrate
2.  Construction
3.  Finishing Agent

Sewing Thread Classification based on Substrate

1. Natural Thread: These eco-friendly threads provide high breathability and a softer touch. Common examples include cotton, also known for its strength and versatility; linen, which is strong and lustrous; and silk, which is luxurious and smooth. However, compared to synthetic fibers, natural fibers might be less resistant to wear and tear. 
2. Synthetic Sewing Threads: Threads made out of synthetic man-made fibers offer superior strength, uniformity, and resilience against elements. Polyester and nylon are popular choices due to their durability and ability to handle sewing products.

Sewing Thread Classification Based on Construction:

1. Spun Thread: Spun yarn is made by twisting staple fibers or filaments together to make a close-knit thread without the addition of any additional materials. It may contain a single type of fiber or be a blend. The most widely used blends of spun thread are cotton-polyester and wool-acrylic fiber blends.
2. Core-Spun Thread: Corespun threads, sometimes referred to as “pcore,” “poly core,” or “cotton core,”. made by twisting staple fibers around a central filament core, usually made of polyester for extra strength. Usually, a staple polyester or cotton wrapper is wrapped around a continuous filament to produce a full core-spun thread. A bundle of polyester fibers is needed during the spinning process, and then these yarns are plyed into a sewing thread.
3. Filament Thread: Filament thread is a type of sewing thread made from long, continuous strands of fibers by either twisting them or grouping them. This gives filament thread some key advantages like higher strength, smoothness, uniformity, etc.

Sewing Thread Classification based on Finishes:

1. Flame Retardant Finish: Flame retardant chemicals are applied as finishing agents. This finish makes the sewing thread more resistant to igniting or burning. Flame-retardant finishes are mostly needed where fire safety is the main issue, like garments for firefighters, flame-retardant aprons, curtains, or upholstery in public spaces.
2. Anti-Static Finish: Anti-static agents, a special type of finishing agent, are used on the thread during manufacturing to reduce the generation of static electricity on the thread. It also prevents dust and dirt from clinging to the finished product, especially in synthetic fabrics.
3. Water Repellent Finish: The water-repellent finish is mainly used to prevent water penetration into fabric by making the sewing thread more water-resistant. A group of water-repellent chemicals are applied to the thread during processing. These chemicals create a microscopic barrier on the thread surface that helps water droplets bead up and roll off rather than soak in.

Application

According to the ASTM, 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 or parts of fabrics.

These threads are used in many types of garments, upholstery, air-supported fabric structures, and geotextiles to attach different components by forming a seam. The primary function of any seam is to provide uniform stress shifting from one piece of fabric to another and preserve the overall authenticity of the fabric assembly.  High-temperature-resistant threads can withstand and hold the seams secure in their position in extreme temperature conditions around 270ºC–1100ºC. 

Threads, which are made from glass, carbon, polytetrafluoroethylene, steel and aramid fibers, polyesters, polypropylene, nylon 6, and nylon 66, are widely used for low-temperature applications such as car upholstery, the leather industry, and packaging materials like cement and fertilizer bags. From stitching wounds to performing any big surgery, medical sutures are also special types of threads used. These threads are also designed to fulfill other important applications.

Therefore, sewing thread is one of the most valuable accessories in a garment, as well as
textile sectors. Where a quality check is crucial for garment making, a small thread failure can aggregate a total loss in investment in production.

Reference:

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2. Noor Ahmed Raaz. Textile Merchandising. Sewing Thread Construction in Garments [Internet].July 17, 2016. [cited 2024 April 4]. Available from:https://textilemerchandising.com/sewing-thread-constriction-garments/#google_vignette

3. Maklaya Ata. Maklaya Creates. Types of Sewing Threads [Internet].October 16, 2023. [cited 2024 April 4]. Available from:https://makylacreates.com/types-of-sewing-threads/

4. Jahanara Rony. Fashion2Apparel. Classification, Properties, Factors, and Basic Requirements of Sewing Thread. [Internet].[cited 2024 April 4]. Available from: https://fashion2apparel.com/classification-properties-of-sewing-thread/

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MD. ZUBAER JISAN

Jisan Zubaer is majoring in textile engineering at DWMTEC and exploring the fields of material science, wearable technology, nanomaterials, and smart textiles. a sustainability enthusiast who wants to combine the best aspects of engineering with sustainable fashion.

Presently working as a content writer, Jisan’s love of books and articles gives his diverse profile more nuance. As a project developer, he works to integrate sustainability and innovation into the future.