How is selvedge denim made?

Denim is the soul of jeans, want to know how to choose high-quality jeans? Why do jeans fade? You need to understand how denim is made first.

Raw material Of Selvedg denim

The quality of cotton determines the quality of jeans.Cotton is the most common textile fiber and the most important raw material needed to make denim. To make high-quality jeans, the first condition is high-quality yarn, and the quality of yarn depends on the quality of cotton.

Assuming the denim is made of 100% cotton, the first step is to purchase cotton.In developed countries, cotton is picked with machines. In developing regions, such as Africa and Southeast Asia, it is usually still done by hand.

There are great differences in the quality of cotton from different origins, and different varieties have different characteristics, such as fiber length, fineness, maturity, strength, color, and feel.

Generally speaking, it is considered to be high-quality denim, and the cotton used is mainly from American cotton, Egyptian cotton, Zimbabwe cotton, and Xinjiang cotton, which is also a good choice.

No matter where the cotton comes from, it must go through the processes of picking, cleaning, carding, sorting, etc. in preparation for the next step.

Of course, cotton is not the only factor that determines the quality of denim.

Spinning Of Selvedg denim

Spinning also affects the style of the fabric and the way it fades.

Spinning, spinning short cotton fibers into long yarns (using twisting methods to hold them into a continuous and infinitely extending yarn), which is easy to weave into cloth.

Before the Industrial Revolution, spinning was done by hand.

Today, the commonly used spinning methods are ring spinning and open-end spinning. Generally speaking, ring yarn has less hairiness, higher strength and better quality. The open-air spinning process is short, the raw material is short, the yarn wool, the count and twist cannot be very high, and the price is also low.

Open-end spinning produces faster, more uniform yarns, and is often used in less expensive jeans. Ring-spun yarns are softer and more uneven, more slub-like(slub raw denim), and less absorbing of indigo dye, resulting in more contrasting fading.

If you want to make stretch denim, you need to add elastic fibers during the spinning process, and ring spinning works best.

(Elastane fibers are spun directly into the core, and cotton fibers are wrapped around the elastane fibers. This maintains the soft feel and fading properties of cotton while adding elasticity.)

Indigo dyeing Of Selvedg denim

The spun yarn is eventually woven into denim, but denim is a yarn-dyed fabric that is dyed first and then woven, so the yarn is dyed first.

In regular jeans, only the warp is indigo dyed, and the weft is made of natural yarn. The color of the fabric depends on the color of the warp, which is why the denim is blue on the front and white on the back.

 

Three elements of indigo dyeing: indigo dye + caustic soda + insurance powder. Under alkaline conditions (caustic soda), indigo is reduced to a water-soluble leuco with affinity for fibers with a reducing agent (hydrosulfite), and after dyeing the fibers, it is oxidized into insoluble indigo and fixed in the yarn to complete the process. Indigo dyed.

 

There are many ways to dye yarn, the most common are rope dyeing and sheet dyeing.

 

Rope dyeing is currently the most commonly used indigo dyeing method in the industry. After the ball is warped, the warp bobbin forms bundles of yarns of varying numbers, which are immersed in the indigo dyeing tank like ropes. When the yarn is removed from the dyeing tank Immediately afterwards it will turn yellow-green. The yarn will turn blue after redox in the air. After dyeing, the whole process is completed after re-warping and sizing.

 

Sheet dyeing is a dyeing method in which the white yarn is flattened into the dyeing tank, and a certain number of warp beams are introduced into each dyeing tank. Dyeing of dyes. After pre-drying and sizing, warp yarns with uniform color and luster can be obtained, which can be directly used for weaving.

 

Relatively speaking, rope dyeing and air exposure oxidation time are more suitable for creating dark indigo shades. For sheet dyeing, after the yarn is warped on the shaft, the yarn is formed into sheets for the integrated production of dyeing and sizing. Relatively speaking, the process is less and the process is shorter. It is more suitable for small batches and multiple frequencies, and can also be used for high-count yarns. category.

 

Compared with other dyeing processes such as sheet dyeing, rope dyeing has its own advantages and disadvantages.

 

But for raw denim lovers, due to the dyeing properties of rope dyeing, the indigo dye cannot fully penetrate into the core of the yarn, so it is more likely to produce a high-contrast color fading effect.

 

Indigo denim fading principle:

Due to the way denim is dyed, indigo dye cannot fully dye the core of the yarn– indigo selvedge denim from WingFly selvedge denim fabric manufacturer and wholesaler. With washing and rubbing, the indigo dye remaining on the surface of the yarn is rubbed away, revealing the original white core.

 

Weaving

 

The indigo dyed warp (vertical) is interwoven with the white weft (horizontal) through a specific weave to create denim.

In order to interweave the warp and weft yarns to form a fabric on the loom, the entire warp yarn must be divided into upper and lower layers according to the requirements of the fabric organization to form a weft feeder (shuttle, gripper, rapier, air jet or water jet, etc.) The passage through the space – the shed, in order to introduce the weft yarn and interweave with the warp yarn.

 

Shuttle refers to the use of narrow shuttle looms (old-fashioned looms), while grippers, rapiers, air or water jets, shuttleless looms (modern looms) are used. The difference between a shuttle loom and a shuttleless loom is that the denim produced by the shuttle loom is much narrower, and has a selvedge on the edge, which is commonly referred to as red edge/red ear, so this This kind of narrow denim is also collectively referred to as red edge cloth- red selvedge denim.

The so-called shuttle loom is equipped with a shuttle, and the shuttle is used to drive the weft to reciprocate in the horizontal direction continuously, and then the edges on both sides of the fabric form selvedge.

 

But since the color of the selvage is determined by the color of the selvage yarn, there will also be black ears, golden ears, white ears, blue ears, purple ears, etc.

It should be emphasized that in terms of product craftsmanship and quality, there is no essential difference between red-edged fabrics and other denim fabrics. Whether it is red ear or any other ear, it does not mean that its quality is better. Its price is generally higher, but because this fabric is a product of low productivity, time-consuming and labor-intensive, and the price rises due to high costs.

In fact, the presence or absence of selvage is irrelevant to most consumers, so, starting in the 1940s, the slow and inefficient narrow shuttle looms were gradually phased out by large-scale commercial production.

Of course, in the eyes of raw cow lovers, red ears are not about quality, but about a retro feeling. Levi’s was the first brand to use red edging, and it was it that created this iconic denim feature, which has led to a lot of imitations from vintage brands.

 

Finishment Process Of Selvedg denim

Basically, denim can be cut and sewed directly into jeans after weaving, which is called raw denim, dry denim or unwashed denim, which is what we call raw cows. You can think of this denim as raw denim, untreated greige denim.

But this untreated denim will shrink to some extent after the first wash. Therefore, whether it is the original cow brand or other mass-produced jeans brands, most of them will choose sanforization denim, that is, denim that has been pre-shrinked.

 

(In fact, there are very few completely untreated denim on the market.)

 

During the spinning, dyeing and weaving of denim, the yarn is under continuous tension, stretching both its length and width. If the fibers do not shrink to their original size before the denim is made into jeans, then once the fibers relax and return to their normal length, they shrink when washed.

 

Pre-shrinking (Sanforization) refers to pre-shrinking the fabric in advance through processes such as water, steam, heating and pressure to facilitate subsequent tailoring and design. With jeans made of pre-shrunk denim, the shrinkage has been reduced from 5-10% to a maximum of 1-3%, and the shrinkage is already minimal. Whether it has been washed or not, it has little effect on the shrinkage of the jeans, which is more convenient for size selection.

 

Many people will ask whether sanforized and one-wash are raw cattle. This is a bit difficult to define. In terms of process, they are neither raw cattle nor washed cattle. It can be said that the two are gray areas. I prefer to call them different states of aurochs. Anyway, whether it has undergone pre-shrinking or desizing treatment will not have much impact on cattle raising.

 

There are two types of finishing: functional finishing, which corrects or prevents dimensional stability problems, and creative finishing, which improves the look and feel of fabrics.

 

While avid raw cow lovers want jeans to remain in their most authentic and pristine condition, most consumers prefer a soft and comfortable wearing experience and a personalized look created by washing.

 

After finishing the denim grey fabric, it can remove the hairiness and impurities on the surface of the fabric, make the fabric surface smooth and smooth, and the color is bright; eliminate the potential shrinkage internal stress of the fabric, control the shrinkage rate of the finished product in the warp and weft direction, and eliminate the potential weft yarn skew internal stress of the fabric, so that the product Get a stable shape ahead of time; change fabric feel and sewing performance. This is the last link of denim fabric production, exporting finished fabrics for garment processing.

In fact, ordinary indigo jeans can no longer meet the needs of the market, which is constantly demanding new colors and softer touches, which is why denim manufacturers are constantly exploring new technologies to enhance the texture, style and visual effects of the fabric. .

 

This In-depth research and understanding of the production process of denim fabric,does it have any help for you to choose denim fabric/selvedge denim fabric?

Welcome to share your thoughts with us~

Here WingFly Selvedge Denim has thousands and thousands of selvedge denim fabric ready for you to choose from,order quantity from 50-3000+yards are warmly welcome and acceptable.