Denim: Manufacturing Process, Properties, and Types

By Eman abdallah Kamel

Eman is a writer and engineer. She graduated from the Faculty of Applied Arts in Egypt with a bachelor’s degree in textile science. She is interested in writing about fibers and many other topics.

Denim

Denim is made from 100% cotton and is one of the oldest fabrics in the world. It is the favorite garment of all age groups, and because of its popularity, a lot of development work has been done in the past few decades.

Denim fabrics are available in many colors, but the most popular is indigo denim, where the twist thread is dyed while the weft thread is left white. As a result of the twisted-faced twill weaving, blue warp threads dominate on one side of the fabric, while white weft threads dominate on the other. Jeans made of this fabric are mostly white inside.

Every year, about 15 billion meters of denim fabric are produced globally to manufacture about 10 billion pieces of clothing. Denim fabric is used to make aprons, capri pants, cloth face masks, dresses, hats, jackets, jeans, overalls, shorts, skirts, suits, shoes, sneakers, belts, handbags, wallets, upholstery, lampshades, and various other common consumer items.

The global denim market was valued at $56,178.1 million in 2017 and is expected to grow at an annual rate of 5.8% from 2018 to 2023.

The industrialized countries that produce the most denim are China, Turkey, Bangladesh, India, Pakistan, Mexico, and Brazil.

Greensboro, North Carolina, White Oak Cotton Mill dyehouse. Formerly, Cone Mills Corporation was the world’s largest denim manufacturer.

A Brief History

The story begins with “dungaree,” which is another word for “denim.” This sturdy fabric was first designed for trousers in India and was worn by Portuguese sailors. The dungaree fabric was originally a common Indian cloth, and then it became a sailor’s costume. In the United States and Australia, dungaree fabric was popular as durable work pants worn by shepherds, farmers, cowboys, and miners.

Originally, denim was known as “Serge de Nîmes,” named after the textile city in southern France. The name may have been shortened to “denim” or “nim” when the fabric was imitated in English factories.

The history of jeans dates back to the Italian port of Genoa, also referring to sailors’ trousers. There may have been contact with the Indian dungarees as well, through the Red Sea trade or Mediterranean links with Portugal. The uniform for American sailors since 1916 has been jeans with a white cotton hat. Sailor trousers, including those worn by the US Navy in the 19th and 20th centuries, were called dungarees. Trousers were made of rough and durable fabric used to make sails and tents as well. Sailors needed wide-legged trousers for ease of wearing and operating on the ship in wet conditions.

Types

Raw Denim or Dry Denim: This refers to jeans that have not been wet or treated in any way before purchase. These jeans can be left unwashed for six months to a year, allowing them to take on the shape of the body. It is important to pre-wash raw denim before wearing it.
Stretch Denim: It is incorporated with stretchy synthetic fiber like Lycra/spandex, which gives it stretch.
Sanforized Denim: This fabric has been treated so that it does not shrink after washing.
Colored Denim: The blue color or shades close to blue are attained through indigo dyeing. Sulfur dye creates other colors of denim fabrics, such as black, pink, gray, green, red, etc.
Black-Black Denim: This is an expression used for denim where the warp thread is black instead of blue and is also dyed black after weaving.
Waxed Reverse Denim: This is a fabric that has a layer of wax on the backside to be waterproof. It is mostly used to make bags.
Left-Hand Twill: This is a weave in which the grain lines extend from the top left-hand corner of the fabric towards the bottom right. It usually occurs in piece-dyed denim, where left-hand twill fabrics are woven from single-ply yarns in the warp. Left-hand twills have a softer feel after washing than right-hand twills.
Selvage Denim or Self-Edge Denim: Denim fabric with edges finished with a ribbon that is usually orange or red. This denim is distinguished by its quality. Japan is the largest producer of this kind of denim fabric.
Poly Denim: This is a fabric blended with polyester fibers. It has a very soft feel, is easy to care for, and has a somewhat stretchy feel. The sewing of jackets, shirts, and hats is very popular.
Crushed Denim: This fabric is woven and treated to look permanently wrinkled or crushed.
Open-End Denim: This was introduced in the 1970s. Cotton fibers are mock-twisted by blowing them together. Open-end denim is bulkier, coarser, and darker, as it absorbs more dye.
Rapid Skying: This is a patented oxidation process developed by Tessitura di Robecchetto Candiani in 1992 that speeds up the skying phase of indigo dyeing.
Thermal Denim or Double Denim: This fabric features a lightweight, glued denim fabric. It makes the garment look like it’s quilted.

Ring/Ring Denim. Image source: buddhajeans.com

Ring/Ring Denim: This fabric uses ring-spun yarn for both warp and weft. It is possible to combine the warp ring-spun weave with an open-end weft to obtain a lot of durability and feel for the traditional ring/ring denim at a low cost.
Acid Wash Denim or Marble Denim: This refers to the finishing achieved in the denim fabric using a chlorine-soaked pumice stone. The color of the fabric fades from corrosion and creates an attractive contrast to the indigo color. Then the fabric is rinsed, smoothed, and dried.
Bull Denim: This is an extremely sturdy and tough fabric due to its 3×1 twill construction. In most cases, this type of denim is used for upholstery or home decor since it is very durable and heavy.
Ecru Denim: This fabric has the natural color of denim without dyeing.
The Printed Denim: This is colored with different graphics, often in contrasting colors, and intended to respond to fashion trends.
Reserve Denim: A new use of denim turned inside out to give jeans a different look.

Types of jeans based on cuts include skinny jeans, boot-cut jeans, straight-leg jeans, wide-leg jeans, and bell-bottom jeans.

Types of Jeans Based on Cuts

Skinny Jeans: These are cut to be tight all over the leg, from the thigh to the ankle. They are usually made of stretch denim to be easy to wear or take off.
Boot-Cut Jeans: These types of jeans work well with ankle boots.
Straight-Leg Jeans: They appear to have a straight up-and-down fit through the entire leg, and they can be on the baggy, relaxed-fit, or fitted kind.
Wide-Leg Jeans: This style of jeans is cut wide all over the leg, starts to flare around the mid-thigh, and then continues down into the wide-leg opening.
Bell-Bottom Jeans: This type of jeans has a snug fit through the thigh and expands from the knee to the leg opening.

Properties

Denim is very soft, breathable, and comfortable to wear.
The fabric is very durable and does not snag or tear easily.
Denim easily absorbs water and dye.
The fabric dries slowly.
Denim resists static electricity buildup.
It wrinkles easily.
It holds up well to heat and detergents.

Did You Know?

Research has proven that denim blended with jute fiber gives the fibers more durability and adds more beautiful shades to denim.

Manufacturing Process

The denim manufacturing process includes many stages:

Carding,
Spinning,
Dyeing,
Weaving,
Cutting and Sewing,
Finishing.

1. Carding

The cotton is taken out of the prepacked bales to be checked before undergoing the carding process. Cotton is carded by running it through machines with bent wire teeth. This process cleans, detangles, straightens, and holds cotton fibers together.

2. Spinning

Other machines then join several slivers together to be pulled and coiled to make the threads stronger. After that, these threads are placed on spinning machines that wind and stretch the fibers to form the yarn.

3. Dyeing

Denim is dyed before being woven. The dye used is usually synthetic indigo. The denim is dipped into the dye bath several times so that the dye forms several layers. This is the reason that blue jeans tend to fade after washing.

To fix the indigo dye, a small amount of sulfur is applied. A group of starches is then applied to the threads to make them stronger and stiffer.

4. Weaving

The threads are woven on large looms without a bobbin. In this weaving, blue threads are interwoven with white threads. But since the blue threads are stuck together more closely than the white threads, the blue color dominates the fabric.

5. Cutting and Sewing

Denim fabrics are cut according to the design, then they go to sewing machines to be stitched by industrial sewing machines. On the sewing floor, skilled workers sew according to predefined seams and seam allowances. Due to the speed of industrial sewing machines, workers need to be highly skilled to avoid injury.

6. Finishing

There are many types of denim finishing:

By rubbing the fabric’s surface and causing abrasion, the process of scraping makes clothing appear used and old.
“Aged” is a type of wet treatment that gives denim fabric an industrial look through prolonged wear.
Bleach is a chemical process used to make denim fade. The aqueous solution of sodium hypochlorite is a liquid bleach, and calcium hypochlorite is a dry powder.
Desizing is a washing process that is used to soften denim. During this process, the amylase enzyme removes starch from the fabric to give it softness.
“Atari” is a Japanese expression that describes the selective fading of wrinkle edges. The seams at the front and back of the knees, along the hem, the top of the thigh, and the belt loops are where Atari most frequently appears.
Grinding creates the appearance of age. It is applied to hems, seams, belt loops, pockets, and waist belts.

Pumice Stone

Pumice stones are volcanic stones used for stone-washing garments. They are popular because of their strength and lightness. They are used to soften denim during the laundry process. The stone washing process has many problems, such as damage to washing machines and clothes, increased labor to remove dust from finished garments, water pollution, and backstaining.
The acid color of indigo jeans gives sharp contrasts. This process is done by soaking the pumice stones in chlorine and letting the pumice stones create contrast. Acid-dyed, indigo-dyed denim tends to turn yellow after a wet treatment. The main cause is residual manganese due to incomplete neutralization, washing, or rinsing.
The over-dyeing process can take many forms, as the blue thread can become black, also known as changing blue to black. Blue or black denim can also be dyed in contrasting colors for unusual shadow effects. Also, indigo jeans can be bleached to a neutral color and then brightly dyed.
Enzyme washing is a process used to reduce the negative impact of stone washing, in which denim fabric is washed with enzymes. The enzyme breaks down the surface cellulose fibers of denim fabric, removing them during washing. Some of the indigo dye is also removed from the surface of the cloth.
Petroleum washing is a method of finishing denim developed in 1992 by the American brand Willi Wear. In the process, the left-hand denim is enzyme-washed until it loses most of its color. It is then dyed and put into a silicone lotion, which gives the fabric an oily coating.
A resin bake crease is a process used to replicate the appearance of permanent wrinkles, which typically occur after repeated wear in certain areas.

Denim Care

Clean the denim with cold water. Using warm water will remove the color from the fabric and will also cause it to shrink.
If possible, use a cold water cleaner designed for darker colors.
Turn the jeans over before putting them in the washing machine.
To remove stains, hand-wash the denim in the sink or other large container for best results.
If you don’t have to heat-dry, it’s best to hang your denim fabrics and let them air dry, as this will keep them longer.
Be sure to wash your denim in cold water and air-dry it if possible to maximize the longevity of its color and vibrancy.

Sources

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