Sewing thread

Place of origin:Guangzhou
Brand name:Liqi
Model number:30/3 2500m
Material:100% Polyester fabric
Pattern:White or dyed
Feature:High tenacity
OEM & samples:Yes 2 days get samples
Color fastness:4-5 Level
Test report:Yes !
Application:Sewing tents waterproof fabric
Weight:150- 300g /cone
Packing:100 cones/CTN or customize package
Length/cone:1500y(m) -6000y(m)
Supply:Spun polyester, poly core, waterproof sewing thread
Keywords:Waterproof thread
Features:Good color fastness, low hairiness, ecofriendly, high tenacity

Continuous pad dyeing has become the most popular and efficient fabric thread dyeing process. So, what should we pay attention to when dyeing fabric thread ribbons?

The main points that should be paid attention to in continuous dyeing of fabric thread ribbons are as follows:

1. Fabric thread ribbon raw blank factor weaving thread ribbon raw blank should first pay attention to whether the yarn used is the same batch, because different batches of yarn contain different "oil" situation, such as blending, will become the color factor in the dyeing process; 

Secondly, whether the original blank has been pre-treated, after refining, the original blank dyeing effect is very good. 

Because after treatment, the "oil" on the yarn thread can be removed and dyed directly in contact with the fibers without protection.

2. The uniform pressure of cylinders at both ends of the roll of fabric thread dyeing trough (or rolling mill, dyeing cylinder, dyeing machine). 

The rolling mill of continuous thermal dyeing machine for ribbon usually uses pneumatic pressure. 

There is one cylinder on each side of the roll. 

When the rolling mill runs for a period of time, due to the effect of moisture in compressed air, the pressure at both ends of the cylinder will be different, resulting in uneven liquid rate of billet strip and color difference between edges and middle. 

In addition, the pressure on both ends of the rolls of the rolling mill results in a certain deflection, resulting in inconsistency of the rolling allowance in the edge and color difference in the left, middle and right sides.

3. In order to minimize the influence of roll pressure on the color difference between left, middle and right in the production of fabric thread dyeing trough rolls, the general roll pressure should be controlled above 0.2 MPa. 

In the production process, because of the wear and tear of the rolls, the rolls are required to be calibrated and repaired regularly, otherwise, the discrepancy of the roll residue due to the discrepancy of the rolls will easily lead to the discrepancy of the pattern. 

Rollers with different hardness have different rolling allowances. 

Too hard may lead to insufficient absorption of dyes. 

Too soft may lead to excessive rolling allowance, resulting in a large amount of migration of dyes and color. How much hardness should be determined by strips.

4. Infrared pre-drying temperature of fabric thread tape influences on fabric thread tape. 

After pretreatment and pad dyeing process, polyester thread tape is usually pre-baked by infrared (line) before entering the dyeing box to prevent dye migration during drying and to avoid dyeing defects such as color difference between positive and negative sides. 

When the infrared pre-drying temperature is below 80 C, the color difference between the front and back sides of the thread ribbon is large, and it is difficult to meet the customer's requirements. 

When the infrared pre-drying temperature is above 100 C, the color difference between the positive and negative sides of the ribbon is greatly improved. This is due to the fact that when the pre-baking temperature is above 100 C, the moisture of the ribbon evaporates basically, which greatly reduces the possibility of dye migration. 

Considering the dyeing practice and energy consumption, it is more appropriate to control the infrared pre-drying temperature between 100 and 150 C. 

In production, it is generally decided by the thickness of the strip and the liquid-carrying rate. 

The higher the liquid-carrying rate of the strip, the higher the infrared pre-drying temperature. In actual production, the color difference between the positive and negative sides of ribbon dyeing can not be controlled only by infrared pre-baking temperature, especially the sensitive color numbers such as coffee and dark green. 

The good dyeing effect can only be achieved by the combination of anti-swimming agent and other additives.

5. The influence of fixing temperature on the color of fabric thread ribbon baking oven. 

Baking color is an important part of continuous thermosol dyeing. 

The uniformity of fixing temperature in baking oven plays a key role in controlling the left, middle and right color difference of ribbon. 

After the polyester thread ribbon is pre-baked by infrared ray and then enters the oven, it is necessary to ensure the same temperature, otherwise it will produce obvious color difference. 

The test shows that the temperature difference between left, middle and right of the oven is more than 2 C, and the color of the thread ribbon changes obviously. 

Therefore, dyeing production must ensure that the oven temperature is uniform.

6. The influence of moisture content of fabric thread tape on the color difference between left, middle and right of fabric thread tape 

The polyester filament thread will be treated with oil before dyeing. 

Before and after dyeing, the ribbon is usually dried, and the uneven surface temperature of the drying barrel will cause the difference of moisture content of the blank thread ribbon, and serious color difference of the left, middle and right thread ribbon will be caused. In the dyeing process, in order to avoid the left, middle and right color difference caused by the different moisture content of the blank thread strip, it is necessary to ensure that the blank thread strip is thoroughly dried before the dipping pad dye solution, and the drying drum is regularly overhauled.

7. As far as production management is concerned, the main factors affecting the left, middle and right color difference of polyester thread ribbon dyeing are as follows.

(1) Variations in fabric thread structure, warp and weft density, warp tension and thickness of semi-finished fabric will cause dyeing discrepancy. 

Because of the difference of production efficiency between loom and dyeing machine, the colour difference occurs when the green ribbons produced by different looms are dyed on the same dyeing machine, or even when the different batches of ribbons are dyed in the same dyeing machine. 

In order to minimize the influence of quality difference on dyeing color difference, weaving and dyeing must coordinate and co-ordinate production plan, and do a good job of stock management of green belt, so as to achieve "first in first out".

(2) The management of the baking oven on the fabric thread belt loom should be regularly repaired and maintained to ensure the normal operation of heating equipment (such as heating pipe, burner, etc.), normal temperature rise and control. In the actual production process, it is also necessary to keep the air duct in the box unblocked and the filter screen clean. 

It is very important to adjust the tension of the blank strip in the feeding device of dyeing machine. 

The tension of the blank strip before entering the dyeing trough must be basically the same so as to ensure the consistency of the liquid carrying rate and the color consistency. 

It is also important to control the tension exerted on the ribbon by the dyeing machine. 

Because the tension of the dyeing machine is regulated by frequency conversion control, the normal frequency conversion control signal of each process point should be ensured and the faulty parts should be repaired in time.

(3) The compatibility of dyestuffs in fabric thread dyeing and chemicals has a great influence on the color difference between the positive and negative sides of the thread ribbon. 

When different formulations produce the same colour number, the colour difference between the positive and negative sides of the ribbon is large. Generally, disperse dyes with the same or similar sublimation fastness and type (S, SE, E) are selected for compatibility, and the dyeing effect is better. 

In addition, the auxiliary use of swimming retardant, penetrating agent and leveling agent can also play a role in controlling the color difference of dyeingof the fabric thread, but it needs to be used reasonably.