Denim is a heavy yarn-dyed warp-knitted twill. Warp is dark, usually indigo, and weft is light, usually light gray or boiled white yarn. Also known as indigo denim.
Denim originated in the western United States and got its name because herders used it to make clothes and trousers.
The warp yarns were dyed by sizing one-step dyeing process, and the yarn counts were 80tex(7), 58tex( 10) and 36tex( 16) respectively, and the weft yarns were 96tex(6), 58tex( 10) and 48 tex (658 tex).
It is made of 3/ 1 and various twill, plain or crepe weave denim. After shrink-proof finishing, the shrinkage of grey fabric is smaller than that of ordinary fabric, with dense and thick texture, bright color and clear structure.
Extended data:
Denim type:
1, bamboo joint
When designing slub yarns with different yarn numbers, different slub thicknesses (relative to the base yarn), different slub lengths and pitches, and properly arranging the slub yarns in single warp direction or single weft direction and warp and weft direction with ordinary yarns with the same yarn number or different yarn numbers, various slub denim can be produced, and various hazy or clear plaid denim can be formed after washing.
In the early days, almost all slub denim used ring spinning slub yarn. Because it can be spun into slub yarn with short length, small pitch and relatively high density, it is easy to form dense embellishment effect on the cloth surface, mainly in the warp direction.
2. Ring spinning yarn
With the development and application of new technologies and equipment such as ring spinning with high speed, large package, fine winding and no knot, the shortcomings of short spinning length, low production efficiency and many knots have been solved.
The situation that denim yarn is replaced by air-spun yarn is changing rapidly, and ring spun yarn is likely to make a comeback. Because ring spinning denim is superior to air-spun yarn in some properties.
Such as hand feel, drape, tear strength, etc. At the same time, influenced by people's psychology of returning to nature and pursuing originality to develop cowboy style,
The more important reason is that the surface of the ring spun denim garment will present a hazy bamboo-like style after polishing and washing, which meets the individual needs of today's denim garment.
Ring spinning slubs can be spun into shorter and denser slubs, which also promotes the development momentum of ring spinning denim.
3. Weft elasticity
With the adoption of spandex elastic yarn, denim varieties have developed into a new field, which can make denim clothing close-fitting and comfortable, and then match with slubs or different colors, making denim products more suitable for fashionable and personalized consumption needs, thus having great development potential.
The elastic elongation is generally 20% ~ 40%, depending on the weave design of the fabric. The smaller the warp and weft tightness on the loom, the greater the elasticity. On the contrary, when the warp knitting tightness is fixed, the greater the weft elastic yarn tightness, the smaller the elasticity, and the weft tightness reaches a certain level, or even loses elasticity.
In addition, the outstanding problem of elastic denim fabric is that the weft shrinkage is too large, generally above 10%, and even as high as 20% in some cases. The instability of cloth width has brought great difficulties to garment production.
The first solution is not to stretch the elastic force too much in product design, generally 20% ~ 30%, that is, to maintain a certain degree of warp and weft tightness, and to increase the tension appropriately in pre-shrinking finishing to make the cloth net shrink greatly.
So as to obtain a lower residual shrinkage of the finished fabric in the weft direction; Another solution is to heat-set the pre-shrunk elastic denim to obtain a more uniform fabric width, a more stable and lower weft shrinkage rate, and meet the requirements of garment processing and production.
4. Color matching
In order to increase the color and tone changes of indigo denim varieties. For example, indigo dye black sulfide, indigo dye grass green sulfide, black green sulfide, blue sulfide and so on. To meet the individual needs of the market.
At the same time, denim production enterprises have their own patented new denim varieties to improve market competitiveness. In this regard, attention should be paid to controlling the concentration of mother liquor as much as possible to prevent excessive overflow of dye liquor from causing dye waste and expanding environmental pollution.
5. Special colors
Because the clothes made of super indigo dyed denim or super indigo dyed denim can get rich and bright colors after sanding and washing, they are widely welcomed by consumers.
"Super indigo" dyed denim has two characteristics: extremely deep dyeing depth and excellent color fastness to rubbing and washing.
The former means that the amount of indigo dye dyed on the yarn per unit weight (generally expressed as% of the dry weight of the yarn, called% of the dyeing depth) is particularly large.
For example, the dyeing depth of conventional denim warp is 1% ~ 3%, while the dyeing depth of "super indigo" needs to reach more than 4% to be called super indigo or super deep indigo.
The latter means that "super indigo" dyed jeans need to be washed repeatedly for more than 3 hours, and their color depth can still reach or exceed that of conventional dyed jeans without washing, and their color light is much brighter than that of conventional dyed jeans.
For indigo dyed denim, its essence depends on the penetration degree of the dye into the yarn, not the abrasion fastness of the dye itself (the wet abrasion fastness of indigo is only 1), that is, the better the penetration degree, the better the abrasion fastness.
In the past, the so-called "indigo dyeing rapid water washing process" actually made indigo dye penetrate into the core of fiber very shallowly during yarn dyeing.
In this way, when the denim garment is ground and washed, a thin layer of dye on the yarn surface is ground off, exposing more white yarn cores, so that the color fades quickly, thus achieving the effect of fading immediately after short-time grinding and washing.
On the contrary, the dyeing process of "Super Indigo" requires that the dye can penetrate into the core well, so that the denim clothes can get deep and bright color after grinding and washing.
Because the dyeing depth of "super indigo" dyed denim products is more than 60% higher than that of conventional denim dyeing, the indigo concentration of the dyeing solution will also double, even reaching 3 ~ 4g/L, and it is possible to obtain a deeper color.
In this way, the viscosity of dye solution increases, the fluidity becomes worse, the permeability of dye leuco is affected, and the color fastness of denim decreases, which can not meet the demand of final depth in clothing production.
Therefore, some enterprises adopt the design of increasing the dyeing depth again, so that the indigo concentration in the dyeing solution increases again, and the permeability becomes worse, forming a vicious circle, and still can not meet the requirements of "super indigo" color.
The higher the concentration of indigo in dye solution, the heavier the red light and the darker the color, and there is no "super indigo" effect. This problem is solved by increasing the number of dyeing channels.
For example, if the number of dyeing passes is increased to 8 or even 10, it will not only increase the investment cost and the consumption of dyeing materials, but also increase the difficulty of operation and increase the pollution to the environment.
A better way to solve this contradiction is to appropriately reduce the dosage of sodium hydrosulfite or caustic soda, especially to control the dosage of caustic soda, so that the PH value of the dye solution is stable between 1 1 ~ 12, the dye uptake is the highest, the color is stable, and at the same time, the dyeing tension of warp yarn is appropriately reduced, so as to obtain a better "super indigo" dyeing effect.
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