NEWS

23

2024

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01

Printing and dyeing process and production process automation

blank - sewing head - desizing - scouring - bleaching - impregnation and dyeing solution - steam evaporation curing - hot melt curing - slurry mixing - plate making - roller printing - high temperature evaporation - desizing - impregnation resin - baking - shaping.


Printing and dyeing, also known as dyeing and finishing, is a processing method of textiles, and is also a general term for pre-treatment, dyeing, printing, finishing, washing, etc.

First, the process of printing and dyeing:
blank - sewing head - desizing - scouring - bleaching - impregnation and dyeing solution - steam evaporation curing - hot melt curing - slurry mixing - plate making - roller printing - high temperature evaporation - desizing - impregnation resin - baking - shaping.
1. Blank inspection and sewing of grey fabric:
1) that is, one by one, the grey cloth is sewn into a large roll or a box car, called a cylinder, and the number of a cylinder varies depending on the processing of different types of fabric.
2) The billet inspection is mainly to control the quality of the grey fabric, to see if there are any abnormalities such as yarn drawing, weft file, dead fold, yellow spot, mildew, etc., and at the same time pay attention to check whether the fabric is consistent with the requirements. Under normal circumstances, a batch number is required to pay attention to the inspection.
2. Singeing: burn off the fluff on the cloth surface to make the cloth surface smooth and beautiful, and prevent uneven dyeing
and printing defects due to the presence of fluff during dyeing and printing. Improve the gloss of the cloth surface, improve the finish, improve the pilling resistance (especially for chemical fiber fabrics), and the fabric becomes crisp.

Cold rolling car: a process after singeing, the grey cloth needs to be cooled for more than 20 hours.

3. Sizing:
1) In order to make the yarn lint when weaving, the yarn is sized, so it is necessary to desizing before dyeing in order to color.
2) If the desizing is not clean, there will be defects such as color flowers and pulp spots on the cloth surface after dyeing.
3) After desizing, it is generally necessary to wash it with water, otherwise the PH value of the fabric will be high, and there will be abnormalities such as poor dyeing.
4) There are generally two kinds of desizing methods: in-cylinder desizing and long-distance car desizing, and the former generally has a better desizing effect, but low efficiency.

4. Dyeing: (1) Chemical fiber dyeing method:
A. Room temperature dyeing:
the general temperature is below 100 °C, mainly used for dyeing semi-glossy nylon taffeta, nylon oxford, nylon twill, etc.
This method is prone to abnormalities such as head and tail color difference, left, middle and right color difference, and creases.
B. High temperature dyeing: the
temperature is generally about 130 °C, mainly used to dye polyester taffeta, N66, nylon matting cloth, polyester oxford (filament), etc., this method is easy to produce head and tail color difference, left, middle and right color difference, creases, color points and other abnormalities.
C. Overflow dyeing:
the temperature is about 100 °C to 130 °C, mainly used to dye polyester such as pongee, peach skin velvet, polyester oxford, Taslon, nylon interweaving, etc., polyester silk spinning can also be used overflow dyeing, at the same time, nylon silk spinning and other dyed wrinkles are also used in this way. This method is prone to abnormalities such as color flowers, chicken claw marks, and straight strip dyeing.
D. Warp beam dyeing: suitable for all kinds of fabrics, but it should be used reasonably according to the quality requirements, and the dyeing temperature can be controlled at more than 100 °C to 130 °C.

(2) Dyeing methods of other cloth types:

A. Cotton cloth dyeing: generally use long car dyeing (large quantities are required), pad dyeing (large quantities can also be used in small batches), overflow dyeing (medium and small batches). Reactive dyes (good fastness), direct dyes (poor fastness), and vat dyes (best fastness) can be used.

B, N/C, C/N dyeing: overflow dyeing is generally used, first dyeing cotton and then dyeing nylon, reactive dyes for dyeing cotton, and acid dyes for dyeing nylon (good fastness). There are also direct dyes that are dyed at one time (poor fastness).

C, T/C, C/T dyeing: generally overflow dyeing, first dyeing polyester and then dyeing cotton, disperse dyes for polyester, and reactive dyes for cotton (good fastness). There are also long car dyeing, dyed at one time, using direct dyes (poor fastness).

(3) Dye classification:

A, Acid dyes:

For dyeing nylon fabrics, it is generally necessary to fix the color to improve the color fastness, and also pay attention to the selection of dye combinations and the use of reasonable dyeing processes. Improper selection or too high dosage of fixing agent will cause a hard feel.

B. Disperse dyes: used for dyeing polyester fabrics, it is generally necessary to use reductive washing to improve the color fastness, and at the same time, it is also necessary to pay attention to the selection of dye combinations and the use of reasonable dyeing processes. Disperse dyes pay special attention to the problems of transdyesification and sublimation fastness.

C. Reactive dyes and direct dyes: low-temperature dyes.

4. Drying: (generally divided into two kinds of drum drying and non-contact drying) A. There are two kinds of non-contact drying
: non-contact dryer and setting machine, there is no contact between the fabric and the heater, and the purpose of drying is achieved by spraying hot air onto the fabric. It is mainly used to dry overflow dyed products to maintain the fluffy and rich feel of the fabric. The cost is higher than that of drum drying.
B. Drum drying: The cloth is in direct contact with the drum, and the purpose of drying the cloth is achieved by heating the drum. Mainly used for coil dyeing and warp beam dyeing products (such as nylon spinning, polyester silk spinning, nylon oxford, polyester filament yarn oxford, etc.), Taslon can also be dried on the drum dryer first (but only six or seven percent dry first so as not to cause the feel too hard), and then go to the setting machine to do water repellent processing to improve water repellency. The cost of drying is low.
5. Stereotyping:
A. After the fabric is shaped, the physical and chemical properties are relatively stable, such as: shrinkage, width, warp and weft density, etc., are not easy to change, and the cloth surface is relatively flat. At the same time, some functional processing can also be done in the shaping process, such as water splashing (waterproof), soft, resin, flame retardant, antistatic, super water repellent (Teflon treatment), moisture absorption and perspiration, antibacterial and deodorant, etc.
B. Due to the high setting temperature, attention should be paid to the color change before and after setting, especially some sensitive colors, such as gray, army green, light khaki, etc. The product generally requires alignment of the color after shaping.
C. Shaping can control the width, warp and weft density, shrinkage, etc., especially the control of shrinkage, which directly affects the processing cost, so special attention should be paid to. (The requirement is generally 3% shrinkage in washing, and 2% shrinkage in washing is strictly required). The three main factors that affect the shaping effect are temperature, speed and overfeeding.
D. Introduction to several processing methods:
(1) Water-repellent shaping
makes the fabric waterproof and dustproof;
(2) Soft shaping
makes the fabric feel soft and smooth, but pay attention to whether the fabric will slip. Water repellency and soft styling can be done at the same time to make the fabric both waterproof and soft, but the softener will affect the water repellency.
(3) Resin shaping
is mainly used for fixing the yarn of the fabric and making it feel stiff, some resins contain formaldehyde, pay attention to the selection; Water repellent and resin styling can be done at the same time, and the resin has a promoting effect on water repellent.
(4) Flame retardant styling
has an auxiliary effect on the flame retardant function of the fabric, and flame retardant can also be done at the same time as water repellent styling, but special attention should be paid to the selection of water repellent agent, otherwise the impact on the flame retardant effect is too great.
(5) Antistatic styling allows the fabric to have antistatic function, which can be done at the same time as water repellent styling
, but has an impact on the water repellent effect.
(6) Moisture-wicking
and perspiration setting allows the fabric to quickly absorb sweat, making sportswear more comfortable. It cannot be done at the same time as splashing water.
(7) Antibacterial and deodorant processing
is mainly to make the fabric have antibacterial function, which is mainly used in medical facilities.
(8) Super water-repellent setting (also called Teflon treatment):
It has better waterproof and dustproof effects than ordinary water-repellent styling, and also has oil-proof function. Generally speaking, guests will ask for a DuPont hangtag.
7. Calendering and gluing: A.
The role
of calendering (1) to adjust the soft feel
(2) to make the calendered surface of the fabric smoother, to reduce the gap between the fabric fibers to prevent the velvet effect or to achieve higher water pressure
when gluing(3) Make the glued surface more smooth and beautiful (4) The calendered surface has a bright effect.

B. The three elements of calendering are temperature, speed and pressure. Calendering changes the color of the fabric.
C. Gluing can make the fabric have the functions of waterproof, downproof, windproof, etc., as well as fix the yarn, increase the appearance, thicken the feel and other functions of the fabric, so as to make the fabric more valuable.
D. Acrylic (also known as AC, PA), PU glue, moisture permeable and breathable glue, which can be processed into transparent glue, white glue, silver glue, color glue, pearlescent glue, Youli glue and so on. Corresponding raw materials can also be added to the glue to make it have anti-ultraviolet, flame retardant, anti-yellowing and other effects.
E. Attention should be paid to the control of water pressure, feel (thickness, softness and hardness), uniformity of gluing, peeling strength of glue, washing resistance (whitening), whiteness and so on. Also pay attention to the rubber particles, glue marks, whether it is dry, etc. Pay attention to the effect of adhesive surface waterstop (PVC strip/PU strip).

8. Laminating PVC: pay attention to the thickness and feel of lamination, the peeling strength of lamination, and the quality of the adhesive surface.

9. Other processing: dry PU (release paper), composite, PU leather and so on.

10. Washing: Some cotton cloths, N/C, T/C also have to go through the washing process. There are three types of washing: ordinary washing, soft washing, and enzyme washing (removing floating hair from the surface of the cotton cloth).