Thermosoling polyester dyeing process

Thermosoling polyester dyeing process

Polyester fiber is a thermoplastic fiber in nature so if heat is applied under melting point then it is soft and its fiber bonds are open. Due to heat and plasticizing properties, dyes can enter into fibers. This type of dyeing is called solid solution dyeing. Thermosoling temperature is 200°C -230°C considering the time of this heat use is up to one minute. In this dyeing process, 80-90% dye fix with fiber. 

Recipe : 

Disperse dye: 2-3% based on fabric weight 

Migration Inhibitor ( Sodium alginate ): 10-20 parts/1000 parts 

Water: 1000 parts 

Thermo-fixation or thermo-soling dyeing can be completed in three stages :

a. Padding 

b. Drying 

c. Thermo-fixation 

An elaborate discussion of the above three processes. 

1. Padding: In pad liquor, we add disperse dye which is diluted in the dye bath and confirm dispersion. 

It is very necessary that pad liquor non-foaming microscopically dispersed mixture must be free from specks. Without these suitable thickening agents (3-4° low viscosity), salt-free c.m.c gram/m, sodium alginate, sodium polyacrylate, and super clear gum need to add to the dye bath. Then bath performs the below action :

a) Polyester component absorbs absorb pad liquor

b)During drying slow down dye migration 

c)Even dyeing 

d)By suitable adhesive fabric and dye particle anchoring completed confirmed. Thickener must be used as quality like that which will not increase the viscosity of the padding liquor and can control migration. 

As a pH stabilizer, there is a buffering agent in padding liquor which pH 6.5-7 . 12.5 g/liter Mono sodium dihydrogen phosphate can be used. To evenly dye spreading on the fabric surface a moderately volatile solvent like butanol can be used.  Solvent and thickener produce excellent specks-free padding. We can also use a wetting agent in the pad bath. 

In Padding liquor actual preparation and at 40°C -60°C temperature dispersing agent and thickener need to be diluted in the final volume. Then add dye in some water and dilute and after filtering need to add the above dilute solution. Then add wetting agent and buffering agent and make the final diluted bath volume. 

2. Drying: Padding completed fabric need to dry in a drying chamber. By infrared radiation or hot air blowing need to keep the drying chamber temperature at 135°C. 

3. Thermo-fixation: Dry fabric needs to pass thoroughly thermosoling unit and the temperature needs to keep 200°C-230°C to pass the fabric need 45-90 seconds.

There are five methods of heat application. They are : 

1. Two flat irons 

2. Molten metal bath (takes small time 10s to fix up the dye ) 

3. Infrared unit 

4. Superheated steam 

5. Hot air oven and a combination of hot roll and hot air treatments(Need longer time the 60s to dye fix up )  

Washing off: The last process of the thermo-soling process is washing off. To remove the unfixed dye and other ingredients from the fabric need to wash the open-width form.