Sewing Thread 72p1d

BASIC REQUIREMENTS OF SEWING THREAD Sewing threads must be designed to meet two fundamental functional requirements: 1 Sewability of the thread: It is the ability of thread to produce a seam with minimum number of breakages and least damage to the thread and the fabric during sewing operation 2. Thread performance in seam: It is the ability of a sewing thread to produce the desired functional serviceability in a desired seam. Ie. The thread must ensure satisfactory performance in the seam. It can be determined very well from the “Seam efficiency” Seam efficiency in dex (SEI) = Seam tensile strength x100 Fabric tensile strength

CHARACTERISTIC OF SEWING THREAD

therefore to meet the basic requirements of sewing thread and to be able to withstand severe working condition, it shout posses certain important characteristic. 1. Tensile Strength/Breaking Strength 2. Initial modulus 3. Abrasion resistance 4. Frictional properties 5. Resistance to higher temperature 6. Evenness with negligible fault 7. Elongation 8. Shrinkage 9. Balanced structure 10. Colour fastness

MATERIAL USED: TYPES OF SEWING THREAD 1.

Spun threads i)

Cotton threads

ii)

Linen threads

iii)

Silk threads

iv)

Spun synthetic threads

v)

Spun blended sewing threads

2. Core spun threads 3. Continuous filament threads i)

Monofilament threads

ii)

Multifilament threads

iii)

Textured threads

4. Embroidery threads 5. Technical threads FIBERS USED Varity of natural fibers used in the production of sewing threads, although some have only limited uses. Cotton, polyester and polyamide fibers are most commonly used for the production of sewing threads. Natural fibers and manufactured fibers are also used in different field of application, but their characteristic are closely related to those of the fiber used. Sewing thread fibers are available in dfferent forms, short staple, long staple and filaments. Synthetic fiber for sewing threads must have higher strength, low elongation and low shrinkage fro better performance. Sewing threads also produced from blends of polyester staple fiber and cotton, however, when different fibers used for blends, the constituent fiber should have matching bulk and physical properties. Cotton: Cotton fiber used in the production of sewing threads are selected primarily on the basis of strength. Since long staple cotton are generally stronger and finer, the sewing thread industry normally uses the longest cotton available for the better grades of the sewing threads, especially for the finer counts.

In adition to strength, length and fineness, other criteria are used in cotton selection for sewing threads, such as length variability, nep-forming characteristic and colour. The main varieties of cotton for good qualities of sewing threads are: Egyptian, American, California cottons. Egyptian, American are always used for high quality, fine sized threads, where their extra staple length and fineness coupled with high strength, are required. California cottons are used in the coarser thread industry, based on the application requirement. Linen and silk Linen and silk are little used in sewing thread manufacture. So the main classification is therefore into either synthetic or cotton fibers. Owing to high elastic and lusture, sewing thread of natural silk is still of importance. Silk is available both in filament and broken filaments that spun in to yarn Linen fiber is still used little, especially for making strong and rather stiff threads, but it ghhas been largely superseded by synthetic fiber threads Synthetic threads Because of their strength and high durability, synthetic fiber yarns are now widely used in the manufacture of sewing thread. The most commonly used materials are polyester and polyamide fibers, since these fibers are thermoplastic and subjected to considerable change in their properties when heated either in processing or in use. The most of the synthetic fiber for sewing threads is polyester fiber; its tensile properties and its freedom from discoloration on exposure to heat and light are particularly valuable in clothing industry. The different elastic properties and heat s4etting characteristic, of polyamide fibers are suited tom other uses, including sewing of leather. Viscose Viscose fibers have not yet replaced cotton to any great extent in sewing threads because of their low strength and abrasion resistance and low elasticity when wet, but their great advantage is their high lusture for use in embroidery.

SEWING THREAD PRODUCTION METHOD

The manufacturing of sewing thread is much more complex then most clothing technicians imagine. The thread has to be of much higher quality then a weaving or knitting yarn and thus has to through more process, gradually refining the thread so that it can be used without breakage in modern machine running at speed of up to 10000 SPI. The thread production methods vary depends upon the types of sewing thread. The production method for cotton is longer than that for 100% synthetic –staple-fiber threads.

1. Spun sewing threads Spun sewing threads are made from staple fibers that are spun into single yarns and then plied to make a sewing thread.

Cotton sewing thread preparation

Cotton sewing threads are manufactured in the same as the normal yarn upto single yarn stage, where as plying, cabling onwards processes differ according to the types of sewing thread and their end uses. Single cotton yarns are mostly prepared on three types of spinning systems they are 1. Ring spinning 2. Rotor spinning 3. Air jet spinning

Flow chart for Cotton sewing threads production

2. Core spun synthetic threads Core spun sewing thread is produced by spinning a cover of staple fiber around a filament yarn and then combining these yarns into a threads construction. These threads are offers the combination of advantages of both properties of staple sheath and filament core. The studies show that sewability of core spun thread is comparative better. Core spun yarn can be manufactured by different methods. In industry ring spinning and friction spinning systems are more popular for producing core spun yarn.

Core spun – sewing thread processing sequence

3. Continuous filament threads These filaments are two types: Monofilaments: each threads consists of only one single filament and it is produced by usual filament spinning method. Multifilaments: Each threads consists of many filaments. In this method the continuous filaments are manufactured by 1. Wet spinning method 2. Dry spinning method

3. Melt spinning method After producing the continuous mono and multi filament yarns, sewing threads are produced in three forms depending upon their usage 1) Monofilament threads 2) Multifilament threads 3) Textured threads

Manufacturing sequence of filament sewing threads

Monofilament and multi filament sewing threads are produced from continuous monofilament and multifilament yarns. But textured sewing thread is produced after giving texturing treatment to the continuous filament.

Apart from the type of polymer from which it is produced and type of single yarn, the quality of sewing thread mainly depends on the post spinning operation. Production methods at the stage of post spinning depends on the type of single yarn and vary widely based on the field of application. 4. Textured sewing thread Texturising provides contionous filament yarn with textured surface which improves cooling of the thread and subsequently reduces the risk of polymer fusing at very high sewing speed with modern sewing machine. The rough surface of the texturised threads restricts the movement of the seam. The process flow chart of manufacturing sewing thread from the air jet textured yarns.

Polymer and polyamide filament air jet of false twist textured yarns are being used as sewing threads. They are produced with low twist, so that the bulking characteristic of the yarn are not destroyed. They are widely used in chain stitch and over lock seams for producing action wear articles based on knitted fabrics. Twisting is done in conventional manner same as spun yarn sewing threads for 2 or 3 fold construction. Textured sewing threads are very soft and extensible due to crimp rigidity. Ideally suitable for knit wear and swim wear. It gives excellent seam coverage.

PROPERTIES OF SEWING THREADS 1. Spun sewing threads  Fuzz on surface of the thread provides excellent lubricity  Able to sew on most types of equipment like lock stitch, chain stitch, over edge etc  Least expensive  Greater seam strength and elasticity coupled with high elongation  Used for all kind of articles i.e ladies lingerie to leather garment 2. Core spun threads  Able to run in all type of sewing equipment  Able to work successfully on automatic multi directional sewing machine  Higher strength per size then spun thread  Fibrous surface due to fuzz on their surface results into soft hand, low friction and good lubricity  Used for stitch heavy article like jeans to all verities  Commonly available as P/C and P/P blend form  P/C wrapped core spun thread provide good needle heat resistance  P/P provide good colour fastness, chemical resistance, excellent strength per size and cheaper then P/C wrapped yarn 3. Continuous filament threads 1) Monofilament threads  Produced from a single 100% continuous filament  Cheaper in comparison to other thread types

 Preferred in blind stitch operation on apparel and drapery and quilting operation on bed spreads and quilts. 2) Multifilament threads  Provides excellent abrasion resistance  Exceptionally strong for their size resulting in excellent seam durability  Better used for industrial sewing application like furniture, luggage, sports goods and foot wear  Limited colour availability  Comparatively cheaper 4. Textured sewing thread o It is an ideal thread for over edge, cover stitch and chain stitch machines o Posses excellent seam coverage and seam elasticity due to high bulk o High shine o Less expensive in comparison to other threads

Applications Sewing threads are widely used in clothing manufacture, outdoor application, high temperature application, geo textile etc., they have several textile and non textile application. Some 80% of all sewing threads produced are used by clothing industries. The main classes of clothing requiring threads are Class

Approximate percentage of all threads produced

Dresses and blouses

13%

Shirts and nightwear

5%

Shirts, coats and other outer wears

28%

Under wears

16%

Knitwear Work clothing Sports wear Other clothing accessories

21%

Household furninshing

8%

Upholstered furniture

2%

All other including luggage and leather goods, book binding, canvas goods

7%

Staple fiber sewing threads o Cotton – General sewing, Dresses, shirts, rain wears, Jeans, Overalls, etc. o Linen – Machine buttoning, hand buttoning, button hole gimp o Polyester – General seaming purpose, lingerie, shirts and knit wear, decorative stitching o Core spun threads (P/C) – General stitching, lingerie, shirts, knitwear and heavy industrial sewing o Core spun threads (P/P)- General seaming o Aramid fiber- flame retardant application o Silk – light seaming and decorative stitching

Continuous sewing thread  Silk – Buttonholing and decorative stitching  Polyester sewing – heavy stitching, general stitching, under threads, padding, blind stitching,, quilting and fur industry.  Nylon – knitwear and general sewing, leather good  Airjet textured polyester fiber - general stitching, jeans, upholstery, bedding  Monofilament – suitable for blind stitching and overlocking only, general seaming and general stitching.