Dyeing Processes for Military Training Camouflage Uniforms: Reactive Dyes, Disperse Dyes, and Colorfastness

1. Introduction: Training Uniforms Fade After a Few Washes – What's the Problem?

Many students notice that after a few washes, their military training camouflage uniform is no longer as vibrant as when they first bought it-greens become lighter, browns turn pale, and blacks turn grey. This is not an illusion-it is a sign of insufficient colourfastness.

The reason training uniforms fade is directly related to their fabric composition and dyeing process. Military training camouflage uniforms generally use polyester-cotton blend fabrics, and polyester and cotton are two fibres with completely different chemical properties. They require two different types of dye to colour them separately. If the dyeing process is inadequate, or colourfastness does not meet standards, the garment will fade and bleed after just a few washes.

This article explains the dyeing processes and colourfastness issues of military training camouflage uniforms clearly.

2. The Two Major Camps of Dyes: Reactive Dyes vs. Disperse Dyes

2.1 Reactive Dyes: "Chemical Reaction" with Cotton Fibres

Reactive dyes are the most commonly used dyes for cotton fibres. Their dyeing principle is chemical bonding-the reactive groups in the dye molecules react chemically with the hydroxyl groups (-OH) on cotton fibres, forming covalent bonds. This type of bonding is very strong, so reactive dyes generally have good colourfastness, especially washing colourfastness.

Advantages of reactive dyes:

• Good colourfastness, especially to washing and rubbing
• Bright colours with a complete spectrum
• Suitable for cotton, linen, viscose, and other cellulosic fibres

Disadvantages of reactive dyes:

• Almost no affinity for polyester fibres – cannot dye polyester
• Requires large amounts of salt and alkali during dyeing, with high wastewater treatment costs
• Dark shades (such as black and dark brown) may have lower wet rubbing colourfastness

2.2 Disperse Dyes: "Physical Bonding" with Polyester Fibres

Disperse dyes are dyes specifically for polyester fibres. Their dyeing principle is physical dissolution and adsorption – disperse dyes disperse in water in molecular form at high temperatures (usually around 130°C), penetrate into the polyester fibre interior, and are "locked" into the fibre upon cooling. This type of bonding relies on intermolecular forces rather than chemical bonds.

Advantages of disperse dyes:

• Specific to polyester, with high dye uptake
• Good light colourfastness – suitable for outdoor clothing
• Relatively complete colour spectrum – can dye dark shades

Disadvantages of disperse dyes:

• No affinity for cotton fibres
• Wet rubbing colourfastness can sometimes be low
• High‑temperature, high‑pressure dyeing requires specialised equipment

2.3 Comparison of the Two Dye Types

3. Dyeing Process for Polyester-Cotton Blend Camouflage Uniforms

Military training camouflage uniforms are made from polyester-cotton blend fabrics (such as 65% polyester + 35% cotton), which require dyeing both the polyester and the cotton. Since the two fibres require different dyes, the dyeing process is far more complex than for pure cotton or pure polyester.

There are two common dyeing processes:

3.1 Two-Bath Method

Process: Dye polyester with disperse dyes first → reduction clearing → then dye cotton with reactive dyes → soaping → drying

Advantages: Good dyeing results for both fibres, high colourfastness

Disadvantages: Long process, high water and energy consumption, high cost

3.2 One‑Bath Method (Disperse/Reactive One‑Bath Two‑Step Method)

Process: Add disperse dyes to the same dye bath to dye polyester first → cool down, then add reactive dyes and alkali to dye cotton → soaping → drying

Advantages: Shorter process, water and energy saving

Disadvantages: Difficult process control; dyes may interfere with each other

Actual choice for training uniforms: Due to strict cost control, training uniforms mostly use the one-bath method or simplified processes. If process control is inadequate, colourfastness problems easily arise.

4. Colorfastness: The Core Indicator of Dyeing Quality

Colorfastness is the core indicator of dyeing quality. It indicates how firmly the dye is bonded to the fibre. The higher the colourfastness, the less likely the dye is to come off, and the less likely the garment is to fade or bleed.

There are four common colorfastness indicators for military training camouflage uniforms:

4.1 Rubbing Colorfastness

Test method: GB/T 3920. A standard white cloth is rubbed against the fabric, both dry and wet, graded 1–5 (grade 5 being the best).

Training uniform requirement: Dry rubbing ≥ grade 4, wet rubbing ≥ grade 3. Dark colours (black, dark brown) usually have lower wet rubbing colourfastness.

4.2 Washing Colorfastness

Test method: GB/T 3921. The fabric is washed together with white cloth in a soap solution, and the degree of fading and staining is observed.

Training uniform requirement: Colour change ≥ grade 3-4, staining ≥ grade 3-4.

4.3 Light Colorfastness

Test method: GB/T 8427. The fabric is exposed to simulated sunlight, and the degree of colour change is graded.

Training uniform requirement: ≥ grade 4. Training uniforms are exposed to the sun outdoors – insufficient light colourfastness leads to rapid fading.

4.4 Perspiration Colorfastness

Test method: GB/T 3922. The fabric is immersed in artificial perspiration, and colour change and stainingg are observed.

Training uniform requirement: ≥ grade 3‑4. Training involves heavy sweating – insufficient perspiration colourfastness leads to fading in areas such as the underarms and back.

4.5 Summary Table of Colourfastness Grades

5. Common Dyeing Problems in Training Uniforms and Their Causes

5.1 Fading

Signs: Colour becomes lighter after a few washes – especially dark colours becoming lighter and greens turning yellow.

Causes:

Insufficient washing colourfastness of the dye

• Inadequate soaping after dyeing – surface dye not removed
• Insufficient light colourfastness – fading after sun exposure

5.2 Staining

Signs: When washing, dark training uniforms dye lighter-coloured clothes.

Causes:

• Insufficient wet rubbing colourfastness of the dye
• Surface dye not adequately removed
• Water temperature too high during washing, accelerating dye release

5.3 Uneven Dyeing

Signs: Uneven colour on the garment, with patches of different shades.

Causes:

• Uneven dye liquor circulation during dyeing
• Inconsistent dye uptake between polyester and cotton fibres
• Improper control of the dyeing process

6. National Standard Requirements for Colorfastness

Although military training camouflage uniforms do not have a separate mandatory national standard, they usually refer to the following standards:

• GB 18401-2010 "National general safety technical code for textile products" : specifies minimum requirements for colourfastness to water, perspiration, dry rubbing, and washing (Category B ≥ grade 3)
• GB/T 31888‑2015 "Primary and secondary school uniforms" : specifies requirements for rubbing, washing, light, and perspiration colourfastness
• FZ/T 81007-2022 "Single and lined garments" : applicable to general garment colourfastness requirements

Key baseline: For garments that come into direct contact with the skin, perspiration colourfastness (acid and alkaline) ≥ grade 3, dry rubbing ≥ grade 3, wet rubbing ≥ grade 2–3. Training uniforms fall into the direct skin contact category and must meet these baseline requirements.

7. Buying and Washing Advice

7.1 Buying Advice

• Check the composition: polyester-cotton blend training uniforms require two dyes for separate dyeing-the process is more complex, and colourfastness control is more difficult
• Check the colour: dark colours (black, dark brown) are more prone to insufficient wet rubbing colourfastness than light colours
• Check the standard: confirm compliance with GB 18401 Category B or GB/T 31888
• Check reviews: refer to other buyers' feedback on "fading" and "staining"
• Check the label: reputable products will state the colorfastness grade or applicable standard

7.2 Washing Advice

• Cold water washing: water temperature should not exceed 30°C – high temperatures accelerate dye release
• Wash inside out: reduce surface friction and protect the colour
• Wash separately: wash dark training uniforms separately the first time to avoid staining
• Neutral detergent: avoid alkaline detergents that damage the dye
• Do not soak for long periods: soaking should not exceed 15 minutes
• Dry in the shade: avoid direct sunlight – sun exposure accelerates fading
• Do not iron: high-temperature ironing may cause dye migration and colour change

8. Frequently Asked Questions (FAQ)

Q: Will a training uniform fade on the first wash?

A: It is normal. On the first wash, surface dye on the fabric is washed off – this is normal. However, if the garment fades heavily with every wash, colourfastness does not meet standards.

Q: Why do dark training uniforms fade more easily than light ones?

A: Dark colours require more dye uptake, with more dye accumulating on the fibre surface, making it easier to come off during wet rubbing. In addition, dark colours have higher colourfastness requirements, but in actual production they are often harder to meet.

Q: How can I judge whether a training uniform has good colourfastness?

A: Check the label. If it states "rubbing colourfastness ≥ grade 4" or "washing colourfastness ≥ grade 3‑4," colourfastness is assured. If there is no marking, you can rub the garment firmly with a damp white cloth to see if the cloth picks up colour.

Q: Can I still wear a training uniform that has faded?

A: It can still be worn, but a faded training uniform looks untidy and may affect the overall appearance of the training formation. If fading is severe, replacement is recommended.

Conclusion

The dyeing process for military training camouflage uniforms is a "dual-dye system": disperse dyes for polyester, reactive dyes for cotton. The two fibres have different chemical properties and require different dyes for separate colouring, which makes the dyeing process for polyester-cotton blend camouflage uniforms more complex than for pure cotton or pure polyester. Colorfastness is the core indicator of dyeing quality, covering rubbing, washing, light, and perspiration. In the use scenario of outdoor sun exposure, heavy sweating, and frequent washing, training uniforms place higher demands on colourfastness.

The next time you see a training uniform fade, you will know: this is not simply "poor quality"-it is the combined result of the dyeing process and colourfastness control. When buying, check the label, the standard, and the reviews; when washing, use cold water, wash inside out, and wash separately. Do these things, and the colour of your training uniform will last longer.