Dyeing wetting agents (printing and dyeing penetrants) are indispensable auxiliary agents in the textile printing
and dyeing process. Their function is to help the dye quickly and evenly penetrate into the fiber and improve the
dyeing effect. The following are the specific usage methods and precautions of dyeing wetting agents:
1. Preparation before use
Choose a suitable wetting agent
Choose according to the fiber type:
Natural fibers (such as cotton and linen): Choose a wetting agent with good alkali resistance and strong permeability
(such as fatty alcohol polyoxyethylene ethers, such as AEO-9).
Synthetic fibers (such as polyester and nylon): Choose a wetting agent with hydrophilic groups (such as polyether
modified silicone oils).
Choose according to process requirements:
High temperature dyeing: Choose a wetting agent with high temperature resistance and good stability.
Quick dyeing: Choose a wetting agent with fast penetration speed.
Determine the dosage
The general dosage is 0.5%-2% of the total dye solution, which is adjusted according to the fabric type and process:
Light and thin fabrics: 0.5%-1%.
Heavy fabrics: 1%-2%.
Recommendation: Conduct a small sample test first to determine the best dosage.
2. Usage
Pre-addition method
Steps:
Add the wetting agent directly to the dye solution and stir evenly.
Immerse the fabric in the dye solution and start dyeing.
Applicable scenarios:
Fabrics that need to be quickly wetted.
Processes with short dyeing time.
Step-by-step addition method
Steps:
Add some wetting agent at the beginning of dyeing to help the dye penetrate initially.
Replenish the wetting agent as needed during the dyeing process to ensure the penetration effect.
Applicable scenarios:
Processes with long dyeing time.
Fabrics with high permeability requirements.
Mixed with dye
Steps:
Mix the wetting agent and dye in advance and stir evenly.
Apply the mixture to the fabric by roller dyeing, spray dyeing, etc.
Applicable scenarios:
Processes such as roller dyeing and printing.
3. Precautions in dyeing process
Temperature control
Effect of high temperature: Some wetting agents may decompose at high temperatures, resulting in reduced
effect.
Recommendation: According to the instructions of the wetting agent, control the dyeing temperature within
a reasonable range (such as 60℃-130℃).
pH adjustment
Alkali resistance: Choose a wetting agent that matches the pH value of the dye solution.
Recommendation: Test the stability of the wetting agent at different pH values before use to avoid the failure
of the wetting agent due to pH changes.
Dye compatibility
Interaction: Some wetting agents may react with dyes, resulting in color difference or precipitation.
Recommendation: Conduct a small sample test before use to ensure that the wetting agent is compatible
with the dye.
Equipment cleaning
Residue problem: The wetting agent may remain in the equipment and affect subsequent dyeing.
Recommendation: Clean the equipment regularly to avoid cross-contamination between different batches.
Safe operation
Protective measures: The wetting agent may irritate the skin and respiratory tract.
Recommendation: Wear protective gloves, masks and goggles to ensure that the operating environment is
well ventilated.
4. Common problems and solutions
Uneven dyeing
Reason: Insufficient amount or uneven distribution of wetting agent.
Solution: Increase the amount of wetting agent, or adjust the addition method (such as step-by-step addition).
Color spots or color difference
Reason: The wetting agent is incompatible with the dye, or the temperature of the dye solution is uneven.
Solution: Replace the compatible wetting agent, or strengthen the temperature control of the dye solution.
Excessive foam
Reason: The wetting agent has strong foaming properties.
Solution: Add defoaming agent, or reduce the amount of wetting agent.
The fabric feels hard
Reason: The wetting agent residue causes a film to form on the fabric surface.
Solution: Strengthen water washing to ensure the fabric is clean.
5. Use Case
Dyeing cotton fabric with reactive dyes
Wetting agent selection: fatty alcohol polyoxyethylene ether (such as AEO-9).
Dosage: 1.5% (to the weight of the fabric).
Process:
Add the wetting agent to the dye solution and stir evenly.
Immerse the fabric in the dye solution, heat it to 60°C, and dye it for 30 minutes.
Wash, soap, and dry.
Polyester fabric disperse dyeing
Wetting agent selection: polyether modified silicone oil.
Dosage: 1% (to the weight of the fabric).
Process:
Mix the wetting agent with the disperse dye and stir evenly.
The fabric is coated with the dye solution through a roller, and then pre-dried and fixed at high temperature.
6. Summary
Correctly select the wetting agent: select the appropriate wetting agent according to the fiber type and process
requirements.
Control the dosage and addition method: ensure that the wetting agent is evenly distributed to avoid excessive
or insufficient amounts.
Pay attention to process parameters: temperature, pH value, time and other parameters have an important
influence on the dyeing effect.
Regular inspection and adjustment: optimize the use of the wetting agent according to the actual production
situation.
The rational use of dyeing wetting agents can significantly improve the dyeing quality, reduce production costs,
and enhance product competitiveness.
