Common problems and solutions when using waterproof and oil-repellent agents
Compared with the low prices of Japanese Daikin and Asahi Glass compared to European and American chemical giants, the fluorine-based water repellent market in China’s fabric industry is basically occupied by Japan’s Daikin and Asahi Glass, with Daikin accounting for more than 60% and Asahi Glass accounting for about 20%.
The following is a summary of common problems and solutions when styling Daikin water-repellent agent and Asahi Glass water-repellent and oil-repellent agent for reference.
1. Common problems and solutions for Japan’s Daikin TG series water- and oil-blocking agents in practice
1. The effect of water-repellent and oil-repellent agent is not obvious
Most of the problems lie in the bath. There are anionic substances in the bath. The reasons are:
*Fibers are treated with anionic additives. Because most of Daikin’s water- and oil-repellent agents are cationic and will react
* The dye is anionic and floating colors cannot be rinsed off.
Methods to detect mixed anionic substances:
* Take the bath solution and add anionic disperse dye. If there is precipitation or coagulation, it means there are anionic substances.
2. Fiber pollution
* There are anionic substances in the bath, the finishing agent will agglomerate, and there will be spots on the fibers
* Pressure roller contamination
* Temperature too high
* Presence of oily substances
Countermeasures:
* Water-soluble cationic emulsifier
* Avoid the use of anionic additives as much as possible, and rinse extremely cleanly when unavoidable
* Avoid being mixed with anionic substances
*Slow down the mixing speed. The fluorine-based water repellent agent has good water solubility and directness, and does not require high-speed stirring
3. Color change
Discoloration is a normal phenomenon and usually becomes darker because a water-repellent film is formed on the surface, causing refraction, so the color looks darker.
This problem usually occurs in factories with insufficient experience. Experienced masters will usually lighten the color slightly when painting.
4. Reasons for the gradual decrease in water repellency
*Concentration too low
* The fiber has poor hygroscopicity and only takes away the water blocking agent but not the water, so the concentration drops quickly
* The fabric has been treated with hydrophilicity, and the water-blocking and oil-repellent agent has a hydrophobic group, so it cannot be attached and the water-repellent properties of the fabric are reduced
*Insufficient processing temperature
5. Reasons for poor initial water repellency
* Mainly due to the PU value of the bath liquid. Daikin water and oil repellent agent has strict requirements on the PU value of the bath liquid
* Ionic properties of various fibers in bath solution:
Cotton: weakly anionic
Polyester: It is weakly anionic, and as the pH value increases, the anionicity becomes stronger
Nylon: Below 4.5 it is cationic, above 4.5 it is anionic
Silk: non-ionic
* Suitable pH range for various fibers
Nylon (uncolored): 5-7
(Light color): 5-7
(Intense color): 3-5
Polyester: 3-5
Cotton, silk, non-woven fabric, resin fiber: 5-7
Please strictly follow the above pH range, otherwise the water-repellent agent will not be able to have a wide range of effects, but do not directly neutralize it with acid or strong alkali.
6. Countermeasures for other problems
* Feels bad
First, you must choose a water-repellent agent that can produce a soft feel. Each manufacturer has a water-blocking and oil-repellent agent that can produce a different feel.
If the requirements are still not met, add some silicone softener and a small amount of surfactant. However, this will cause the water-repelling performance of the water-blocking agent to decrease, and the more the amount is added, the more obvious it will be.
* Poor antistatic properties
Add some inorganic salt or quaternary ammonium salt, be careful not to mix in anions
* There are white spots (like chalk dust falling on clothing)
Because the fabric is too hard, add softener
* Bubbles
Add a defoaming agent to avoid mixing in anions, or place a high-power fan next to it
* Methods to re-organize the three defenses
If you really screw up and need to redo it, first use alkali and surfactant to wash off the water-blocking agent film, so you can use the special DANASIST FUP/FUX.
Mechanism of DANASIST FUP/FUX washing off the water repellent film:
DANASIST FUP/FUX replaces the fluorine group and combines with the water extractor group to form a water-soluble substance that falls off the fiber, thereby achieving the purpose of washing off the water-repellent agent film.
Of course, alkali cannot be used on silk and wool, as alkali denatures protein fibers.
2. Common problems and solutions for Asahi Glass AG series water and oil repellent agents in practice
Water and oil repellent agents have been developing more and more rapidly in recent years. Organofluorine resin is a water- and oil-proof finishing agent with excellent performance. It is widely used in work clothes, high-end interior decorations, shoes and socks, bed sheets, luggage, etc. due to its high effectiveness, resistance to deterioration, and ease of use. products. However, many printing and dyeing manufacturers often encounter some problems when using organic fluorine finishing agents, such as poor initial water-blocking performance, poor durability, water-blocking stains and streaks, large color changes, etc. In response to the above problems, through many experiments, we found the causes of the problems and put forward the main countermeasures to solve the problems.
Problem l Poor initial water and oil resistance
1. Reason:
Through experiments, it is believed that there are only three main reasons for poor initial water blocking performance:
First, finishing the cloth; the scouring or coloring cloth is not cleaned enough, and scouring agent, leveling agent, dispersant, penetrating agent and other additives remain on the cloth.
Second, the problem of working fluid is that the concentration is improperly used or the concentration changes during finishing; or, the working fluid is affected by mechanical stirring, temperature, mixing chemicals, etc., and its stability is affected. Then there is the improper preparation sequence of working fluid.
Third, due to the finishing conditions, the water blocking agent is not properly selected, or the drying and baking conditions are insufficient and uneven. The main countermeasures to solve the above problems can start from the following aspects.
2. Main countermeasures
1. Before water-blocking finishing, the finishing cloth should be fully washed.
2. Choose a water-blocking agent suitable for fiber finishing. Newly prepared working fluid may be added continuously during finishing. Strengthen the temperature control of the finishing cloth to prevent the hot cloth from entering the studio directly after drying. Understand the compatibility of the blended chemicals and prepare the working fluid according to the mixing sequence. When other additives are diluted with warm water, they need to be cooled before adding the AG series water blocking agent. The prepared working fluid must be used within 24 hours.
3. The drying and baking temperatures should be uniform, and the baking temperature should not be too low, generally above 140°C.
Problem 2: Poor durability of water and oil repellent agents
1. Reason:
1. The finishing cloth is not washed enough.
2. The finishing conditions, especially the baking conditions, are not met.
3. The influence of cross-linking agent, resin and color fixing agent.
2. Main countermeasures;
1. Cloths colored with direct dyes or reactive dyes and then fixed must be washed thoroughly.
2. Select the appropriate cross-linking agent or resin and use it within the shelf life.
Problem 3: Water repellent stains
1. Reason:
1. The working fluid has poor stability. This can be determined by observing the surface of the working fluid after high-speed stirring to see if there is scum on the roll.
2. Malignant bubbles may occur. This can be touched by hand. If it agglomerates and turns into scum, it is a malignant bubble.
2. Main countermeasures:
1. Pay attention to the temperature of the operating fluid not exceeding 35C.
2. When malignant bubbles are found, add stabilizer (isopropyl alcohol).
Problem 4: Water-repellent streaks
1. Reason:
1. The coloring is uneven.
2. The uneven pressure of the rolling car causes uneven rolling fluid.
3. The permeability of the working fluid is poor and the liquid flows down. This phenomenon is more common in fabrics with poor permeability such as high density.
2. Main countermeasures:
1. Make sure the coloring is even.
2. Use a uniform rolling car, and pay attention to cleaning the rollers and rolling grooves frequently.
3. Use water-blocking agents with high permeability and combined penetrants.
Question 5: The color has changed a lot
1. Reason:
The main reason for the color change is the deepening effect of fluorine-containing resin. This is also a phenomenon that cannot be completely avoided during the water blocking finishing process.
2. Main countermeasures:
To solve the color change, you can confirm the degree of color change through preliminary tests, and then carry out color matching; after finishing, you can replenish the newly prepared working fluid in time (it is better to have an automatic liquid adding device) to prevent head and tail color differences.
The above are the problems that often occur during the finishing of water-repellent and oil-repellent agents. We selected a variety of water-repellent and oil-repellent finishing agents for testing, and found that by adopting the above measures and selecting excellent water-repellent and oil-repellent finishing agents (such as Japan’s Meisei series water-repellent agents), the above problems were basically solved and the water-repellent and oil-repellent finishing agents were improved. Oil effect, high customer satisfaction rate for water-repellent orders. In short, choosing a suitable water-repellent and oil-repellent finishing agent will provide a good foundation for the water-repellent and oil-repellent finishing of the fabric; in the post-finishing process, the finishing cloth, working fluid and finishing conditions are necessary to obtain a good water-repellent and oil-repellent effect. guarantee.
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