What is Fixative in Denim and Washing Color Fixing Agent

Md Mahedi Hasan

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Fixatives mainly used in denim and washing bath for fixing dye or color. It’s act as color fixing agent. In this content we will discuss about fixative composition and properties, objectives, application, storage. So Let’s start.

What is Fixative Agent?

After dyeing or washing treated fabric has some unfixed dying material on the surface. Sometime the dyestuff causes color migration when it is wet or during washing. Color Fixing Agent is applied to dyed fabric to fix the unfixed dye material on fabric. It improves wet color fastness and fabric quality.


  1. Chemical Element: Cat-ionic polymer
  2. Appearance and traits: Colorless to light yellow viscous liquid
  3. Point Subquantity: High
  4. Charge type: Cat-ionic
  5. Bulk density: About 1.07 g/cm3
  6. PH Value: About 4.0 6.5  (0.1% aqueous solution)
  7. Solution viscosity: About 150-500mPa.s (0.3% tap water, 20°C)
  8. Water Solubility: Good

Objective of Fixative

Fixative is suitable for reactive, sulfur and indigo dyes. It is used for dyeing cotton, linen, hemp, wool, and other fabrics to fix the color.

Fixative Color Fixing Agent
Fixative Color Fixing Agent

This Color Fixing Agent is especially suitable for washing machine treatment of garments. It is also suitable for O-type cylinder treatment of cotton knitting. The treated fabric shows good alkali resistance, including mercerizing fastness. It increases the water soaking fastness or excellent washing fastness.

Dye Fixative Color Fixing Agent
Dye Fixative

Reactive polymer polymerization based on cross-linked resin thing. It can form macro-molecular compounds with anionic dyes. It react with fibers to form insoluble substances. Fixative has a very obvious effect on improving the color fastness of cotton fibers and is excellent in various properties. Environmentally friendly fixing agent.

Fixative Action mechanism

Fixative Agent reacts with the cat ionic group on the long-chain molecular bundle and the negatively charged on the dye, and forms a macro-molecular condensate through the bridging of the chain bundle. It also has a certain cross-linking and grafting ability with cotton fibers, and the dense film formed by macro-molecular condensate is also coated on the fibers.

Color Fixing Agent Fixative Action in Cotton Fabric
Color Fixing Agent Action in Cotton Fabric

Performance characteristics:

  • Slightly does not affect the light fastness and shade of dyed products. And fully maintains the original color brightness of cotton fabrics.
  • Have not too much impact on the hand feeling of dyed fabrics.
  • Efficiently improve the color fastness to washing of cotton fiber dyes, and slightly affect the re-wetting property of the fixed color. 
  • Excellent environmental protection performance
  • Highly versatile, It also has a good color fixing effect indigo dyes, especially recommended for dipping process,
  • Fastness is improved Excellent performance.


Color Fixing Agent is high connection formaldehyde-free color fixing products. The following reference dosage is based on its dilution 20% solid concentration finished product KPN-KC -”X” for example)

Color Fixing Agent Dye Fixation Action in Denim Washing
Dye Fixation Action in Denim Washing

a. Dipping process:

Thoroughly soaped and rinsed dyed or fabrics are usable

  • KPN-KC: 06 – (o.w.f – on the weight of material)
  • Treat at 20-40°C for 20-30 mins.

Best for treatment baths, The PH value is between 5 and 5.5. If no other PH regulators are added, additional adjustment may not be required.

b. Padding process:

The concentration of the dipping tank is determined by the liquid absorption rate, and we suggest that the adsorption capacity is the weight of the cloth 1.0 – 3.0%. Generally, it can be referred to as 10-30 g/L; the optimum PH value of the treatment bath is 5-5.5, and it can bathed with cat-ionic and non-ionic finishing agents (confirmation test before use).

c. Stripping, changing color:

1. If counter-staring or even coloring is required, it must be removed first. KPN-KC-“X” products;

  • Solid removal agent SNS: 1.0-3.0% (o.w.f) (greater than the amount of fixing agent)
  • Caustic soda NaOH: 1.0 – 3.0%
  • Temperature: 90-100°C,
  • Time: 20min.

The larger the liquor ratio, the better, it is recommended not to be lower than 1:10, after draining, rinse with hot water, and after dyeing and chemical experiments are confirmed, the cloth surface removal effect no longer affects the level dyeing property, it can be re-stained or stripped.

2. If the peeling and solid removal can be carried out at the same time, the following one- bath method can be used:

Solid removal agent SNS: 1.0-3.0%  (o.w.f) (greater than the amount of fixing agent)

  • NaOH:  Appropriate amount
  • Na2S2O4:  Appropriate amount
  • Temperature: 85-100°C.
  • Time: 20- 40mins, rinse thoroughly.

d. Pumping requirements: 

The raw material is recommended to be diluted to a certain concentration before use, in the raw liquid state, the viscosity is high, which is not conducive to pumping. It is often used to replenish liquid in the way of high level tank.

Material selection for feeding system: Plastic, plastic coated materials, and stainless steel.

Operation and storage

When operating, please wear protective overalls, rubber gloves, and protective goggles. Special attention to this product: Color fixing agent will make the surface of the object slippery after being diluted with water!

Pay attention to cleaning the site with water in time to ensure keep the site clean.

Please refer to this product safety data sheet before using this product. If the product is placed in the open, it is easily affected by moisture and air drying, resulting in crusting on the surface. Therefore, the product must be covered in time after opening and taking the material. Tightly pack lids to avoid crusting on the surface. 

Product shelf life: Under compliant storage conditions the product in the airtight package can be stored stably for at least 24 months.

Material packaging 

Color Fixing Agent can be packed 125 kg/blue PE drum, drum packaging.

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