thread science

8/13/2019 Thread Science

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American & Efird, Inc. Thread Science

10/10/02 Page 1

Thread Science

Introduction: Choosing the Right Thread

Thread is an integral part of many items that we use daily. Certainly the various components ofour apparel are joined with thread but what about the string that is attached to our tea bags?What would happen to upholstery, seat belts, and head liner of an automobile if the thread wereremoved? What about the seams in our tents, back packs, sleeping bags, and other campingequipment? How are the components of baseballs and footballs joined?

Each of these products requires a thread with different physical properties to achieve optimumperformance. If you consider the many uses of thread, the complexity of designing a threadbecomes apparent. Consideration must be given to: Sewability, loop strength, linear strength,elongation, shrinkage, abrasion resistance, colorfastness, and resistance to chemicals, heat,light, etc. Each can affect the desirability of a thread for a particular end-use. A&E threads aredesigned for many general and specific end-uses.

Selecting the proper thread for your product can be simplified if these basic factors areconsidered: required seam strength; type of seam; stitch type and number of stitches per inch;type of material being sewn; type of sewing machines and related equipment; conditions underwhich the product must perform; normal life of the product; and cost effectiveness.

Analyzing these factors would give an indication of which physical properties are most importantin the thread. Selection then becomes a matter of choosing a thread with the most desirableproperties. Of course, thorough testing is necessary to confirm that the thread chosen is indeedthe correct one. A&E will be glad to provide any necessary technical assistance to help youselect the best thread for your use. (See Technical Services .)


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American & Efird, Inc. Thread Science: FIBER

10/10/02 Page 2

Fiber Science

Where Do Fibers Come From?

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

Natural Fibers: Come from plants and animals and are spun or twisted into yarns.Cotton is the most common natural fiber used to make thread. Other natural fibersinclude silk, wool, jute, ramie, hemp, and linen. Natural fibers are generally not asuniform as synthetic fibers and are affected by climatic changes. At A&E, we use cottonas a fiber source for some of our thread. We select our cotton fibers from the bestavailable crops, classifying them depending on the geographic location and climate,seed and type of plant, and the cotton grower's reputation. The two classes of cottonfibers that we use at A&E are SAK (or Supima) cotton that comes from Arizona and CP(or Peeler) that comes from the San Juaquin Valley in California. SAK quality cottonproduces stronger spun cotton threads than CP fibers .

Synthetic Fibers: Are made from various chemicals or regenerated from cellulose suchas wood pulp and cotton waste. We select our synthetic fibers based on their sewabilitycharacteristics, seam performance, ease of dying, colorfastness, and pricing. At A&E,the synthetic fibers that we use as a source to make thread are polyester, nylon, Kevlarfrom Dupont, and Nomex from Dupont.

Fibers Come in What Forms?

When we receive bales of cotton, polyester, nylon, Kevlar, and Nomex, the fiber contained inthe bales comes in one of the following forms:

Staple: Refers to natural fibers that vary in length or to synthetic fibers with filamentsthat are cut to a definite length during the manufacturing process

Continuous Filament: Refers to synthetic fibers of an indefinite length


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American & Efird, Inc. Thread Science: CONSTRUCTION

10/10/02 Page 3

Thread Construction

We manufacture thread based on the following construction methods:

Is made from cotton or polyester staple fibers that arespun into single yarns and then two or more of theseyarns are plied to make a sewing thread. Spunthreads have fuzz on their surfacing giving them a softhand and good lubricity characteristics. Spun threadsare used in everything from women's lingerie to heavyleather gloves. (Example products are: Anecot ,Anecot Plus , Kevlar from Dupont, Nomex fromDupont, and Perma Spun .)

Is made by spinning a wrap of staple cotton orpolyester around a continuous filament of polyesterfibers. Afterwards, two or more of these single yarnsare twisted together to form the thread. Core threadshave fuzz on their surface giving them good lubricitycharacteristics and also a continuous filament corethat contributes to high strength and durability. Whenwrapped with a cotton wrap, core threads have verygood needle heat resistance. When wrapped with apolyester wrap, core threads have excellent chemicalresistance and colorfastness. Core threads are usedin everything from fine blouses to heavy coveralls andoveralls. (Example products are: D-Core andPerma Core .)

Is made from continuous filaments of polyester ornylon that have been textured by pin, disc, or belt andthen heat set to insure proper bulk retention. Texturedpolyester is usually manufactured with regular or midtenacity, continuous filaments depending on theapplication. Textured threads are ideal for overedge,chainstitch, and coverstitch of the finished seam andoffers good seam elasticity. Textured threads areusually less expensive when compared to other threadtypes. (Example products are: Best Stretch ,Wildcat , and Wildcat Plus .)


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American & Efird, Inc. Thread Science: CONSTRUCTION

10/10/02 Page 4

Is made from continuous filaments of polyester thatare entangled as they pass through a high pressure air

jet. This yarn is then twisted, dyed, and wound oncones with lubricant. Air entangled threads are usedin everything from seaming flags to heavy denim

jeans. (Example product is Magic .)

Is made from continuous filaments of polyester ornylon that are twisted together into a cohesive bundleand then plied to make the thread. They are thendyed, stretched, and heat set to achieve the desiredphysical characteristics. Twisted Multifilament threadsare available either soft or with an additional bond forbetter ply security and abrasion resistance. They areexceptionally strong for their size and they haveexcellent resistance and durability. These threads areused for seaming everything from bathing suits toautomobile upholstery. (Example products are: AnefilNylon and Anefil Polyester .)

Is produced from continuous filaments of nylon thathave been bonded together. They have very little twistso that they look like a single cord of yarn. Because ofthe way these threads are made, they appear to be flatand ribbon-like, which provides a high degree of

resistance to abrasion. Monocord threads areexceptionally strong for their size so they are used inthe manufacturing of furniture, shoes, and other heavyduty applications. (Example product is Anecord .)

Normally produced from a single nylon continuousfilament resembling fishing line. Usually monofilamentthreads are used because the thread is translucentand blends in with many colors. Because it has atendency to be stiffer than other filament products, it isnot recommended for seams that may lay adjacent to

the skin. Also, because it is a single filament, it mayunravel easily if the thread is not locked in the seamadequately. Monofilament threads have been used inquilting operations on quilts and bedspreads, as wellas, in blindstitch operations on drapery and apparel.(Example product is Clearlon .)


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American & Efird, Inc. Thread Science: FINISHING

10/10/02 Page 6

Thread Finishing

Once the thread is constructed, the thread may be finished in several different ways to enhanceits suitability for various end uses. The thread finishes used at A&E and the relationship

between construction, fiber type, and finishing are listed below.

Soft: Gassed: Refers to thread that receives no furtherprocessing to change its general physicalcharacteristics. It is dyed to the proper shadeand degree of colorfastness, wound on theproper size package, and lubricated forsewability.

Refers to a finish where cotton thread ispassed through a flame at high speed toreduce its fuzz and have a greater sheen.Gassing is done in a wrap form prior tomercerizing and dyeing.

Mercerized: Glaced:

Refers to a finish where cotton thread istreated in a caustic solution under controlledtension. This process causes the fibers toswell, resulting in greater affinity for dyepenetration. Mercerization increases theluster of cotton threads and at the same timeincreases their strength.

Refers to a finish in which 100% cotton andsome cotton wrapped core threads are treatedwith starches, waxes, and special chemicalsunder controlled heat and then brushed orpolished to a high luster. The result is aglossy, hard finish that protects the threadfrom abrasion and enhances ply securityduring the sewing of hard to penetrate fabrics.

Bonded: Refers to a finish where multifilament polyester or nylon is treated with a special resin thatencapsulates the filaments forming a tough, smooth protective coating on the surface of thethread. This bonding process adds significantly to the thread's ability to resist abrasion andgreatly enhances ply security during sewing.

Relationship Between Thread Construction, Fiber Type,and Thread Finish

Thread Construction Fiber Type Thread FinishCotton wrapped polyester SoftCorePolyester wrapped polyester SoftCotton Soft, Mercerized, or GlacedSpunPolyester Soft

Air Entangled Polyester Soft

Textured Polyester SoftNylon SoftTwisted MultifilamentPolyester Soft or Bonded

Monocord Nylon BondedMonofilament Nylon Soft


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American & Efird, Inc. Thread Science: DYEING

10/10/02 Page 7

Thread Dyeing

Thread is dyed or colored and then finished depending on the application. At A&E, we usepackaging dyeing in which many packages of thread are dyed under pressure in a dye vat.

Packages of synthetic threads are dyed by a similar process that uses high temperature toensure colorfastness, a key thread performance characteristic.

A&E also has state-of-the art dye matching and formulation systems in our dyelab. Thesesystems include:

A Colorite system from Datacolor, Inc., for emailing color matches, which reduces thetime for getting an approved color shade.

A Tecnorama Dos and Dye system, which processes up to eight samples at one time,reducing the time it takes to create formulas for custom colors. The Tecnorama systemalso eliminates the potential for operator error compared to systems where a technician

manually weighs the dyes and solutions.For more information on dyeing and colorfastness, contact the American Thread ManufacturersInstitute, which is a national trade association that represents thread manufacturers:

ATMIThread Committee1801 K. Street NW

Washington, DC 20006-1301

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