Several common problems and solutions in waterproof and oil-proof finishing
With the development of the textile industry, special functional finishing is increasingly recognized by people. Waterproof and oil-proof finishing has developed more and more rapidly in recent years. Organofluorine resin is a kind of waterproof and oil-proof finishing agent with excellent performance. It is widely used in various textiles such as clothing, high-end interior decorations, shoes and socks, bed sheets, luggage, etc. due to its high effectiveness, resistance to deterioration, and ease of use. product. However, many printing and dyeing manufacturers often encounter some problems when using organic fluorine water- and oil-repellent finishing agents, such as poor initial waterproof performance, poor durability, occurrence of waterproof stains and streaks, large changes in color and light, etc. In response to the above problems, through many experiments and practices, we found the causes of the problems and put forward the main countermeasures to solve the problems.
Problem 1. Poor initial waterproofing performance
1. Reason:
Through experiments, it is believed that there are only three main reasons for poor initial waterproof performance:
⑴ Processed cloth: Insufficient cleaning of scouring or dyeing cloth, leaving scouring agent, leveling agent, dispersant, penetrating agent and other auxiliaries on the cloth.
⑵Problems with the working fluid, improper use of concentration or changes in concentration during processing; or, the stability of the working fluid is affected by mechanical stirring, temperature, mixing chemicals, etc. Another reason is that the working fluid preparation sequence is inappropriate and the pH value of the bath fluid is incorrect.
⑶ Due to processing conditions, improper selection of waterproofing agent, or insufficient and uneven drying and baking conditions. The main countermeasures to solve the above problems can start from the following aspects
2. Main countermeasures
⑴. Before waterproof processing, the processed cloth should be fully washed.
⑵Choose a waterproofing agent suitable for processing fibers, and replenish newly prepared working fluid as much as possible during processing. Strengthen the temperature management of processed fabrics, and the drying temperature should not exceed 130°C to avoid previous cross-linking. Avoid putting the hot cloth directly into the studio after drying. Understand the compatibility of the waterproofing agent and prepare the working fluid correctly according to the preparation sequence. The prepared working fluid must be used within 24 hours.
⑶ The drying and baking temperatures should be uniform, and the baking temperature should not be too low, generally above 150°C.
Problem 2: Poor durability of waterproofing agent
1. Reason:
⑴The processed cloth is not washed enough.
⑵The processing conditions, especially the baking conditions, are not met.
⑶The influence of cross-linking agent, resin and color fixing agent.
2. Main countermeasures;
⑴ Cloths dyed with direct dyes or reactive dyes and then fixed must be washed thoroughly.
⑵Choose the appropriate cross-linking agent or resin and use it within the shelf life.
⑶Choose the appropriate waterproofing agent and dosage to ensure durability.
Question 3: Waterproof stains
1. Reason:
⑴The working fluid has poor stability. This can be determined by observing the surface layer of the working fluid after high-speed stirring and whether there is scum on the roll.
⑵ 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:
⑴ Pay attention to controlling the temperature of the working fluid not to exceed 35C.
⑵ When malignant bubbles are found, add stabilizer (isopropyl alcohol).
⑶Waterproofing agent should be used within the shelf life.
Question 4: Waterproof streaks
1. Reason:
⑴Uneven pre-treatment and uneven dyeing.
⑵ Uneven rolling pressure causes uneven padding fluid.
⑶ 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 count, high density and thick fabrics.
2. Main countermeasures:
⑴ Ensure that all pre-treatment processes and dyeing are uniform.
⑵ Use a uniform rolling car, and pay attention to cleaning the rolls and rolling grooves frequently.
⑶Choose a waterproofing agent with high permeability and use a small amount of non-ionic penetrant.
Question 5: There is a big change in color and light
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 waterproofing process. Discoloration is a normal phenomenon and usually becomes darker because a waterproof film is formed on the surface, causing refraction, so the color looks darker.
2. Main countermeasures:
To solve the color and light change, you can confirm the degree of color and light change through preliminary tests, and then carry out color matching; replenish the newly prepared working fluid as soon as possible during processing (it is better to have an automatic liquid adding device) to prevent head and tail color difference.
The above are commonly used in waterproof and oil-proof finishingproblems arise. We selected a variety of waterproof and oil-proof finishing agents for testing, and found that by adopting the above measures and selecting excellent waterproof and oil-proof finishing agents (such as Japan’s Mingcheng series waterproofing agents), the above problems were basically solved and the waterproof and oil-proof effect was improved. Our waterproofing orders have a high customer satisfaction rate. In short, choosing the appropriate waterproof and oil-proof finishing agent will provide a good foundation for the waterproof and oil-proof finishing of fabrics; during the finishing process, the processing cloth, working fluid and processing conditions are the guarantee for obtaining good waterproof and oil-proof effects.
Problem 6: Bad hand feel
1. Reason
The main reason is that the waterproofing agent creates a waterproof film on the surface of the fabric, which makes the fabric feel bad.
2. Main countermeasures:
⑴First of all, choose a waterproofing agent that can produce a soft feel. Each manufacturer has a waterproofing agent that can produce a different feel.
⑵ If the requirements are still not met, add some silicone softener and a small amount of surfactant. However, this will cause the water-draining performance of the waterproofing agent to decrease, and the more the amount is added, the more obvious it will be.
⑶ If it still doesn’t work, replace the waterproofing agent.
Question 7. Blistering
1reason
⑴Whether the waterproofing agent itself is prone to foaming? Try to choose a waterproofing agent with low foaming.
⑵ Residual surfactants (dispersing/leveling agents, reducing soaping agents, etc.) and alkali on processed fabrics. Washing fabrics is key.
⑶ Matching softeners and antistatic agents. Try to choose low-foaming types.
2. Main countermeasures:
In addition to the countermeasures (1~3) above, prepare an efficient and stable antifoaming agent with antifoam properties to add to the working fluid.
Question 8. Roller sticking phenomenon
1. Reason
⑴Continuously observe whether resin or viscous precipitation appears on the roll during processing. If it occurs, it will easily become a waterproof spot.
⑵Stability of the waterproofing agent itself: Screen for waterproofing agents with high stability.
⑶Temperature: The waterproofing agent is an emulsion. Especially in summer, when the water temperature is high, the ambient temperature is high, and the temperature of the fabric being processed is also high, which continuously brings heat into the working fluid and causes the temperature of the working fluid to rise. At this time, the stability of the emulsion is reduced, and the fluororesin is relatively easy to precipitate. (emulsification).
⑷pH: When the pH is higher than 7 and is alkaline, the stability of the waterproof working fluid will decrease, and it will also easily break and precipitate and stick to the roller.
⑸ Mixing of dyes and additives: If the processed fabric is not cleaned, the remaining dyes (mostly anions) will fall off into the working fluid and combine with weak cationic waterproofing agents to cause instability in the working fluid.
⑹ Water quality: Only the filtered river water contains suspended solids or other substances depending on the season. It is easy to combine or flocculate when encountering weak cationic waterproofing agents. It is strictly prohibited to use them when preparing working fluids.
⑺ Continuous roller extrusion and mechanical shearing: When the above problems (1-5) exist, the stability of the working fluid decreases. At this time, it is easier to break the emulsion and stick to the stick during continuous rolling mill extrusion.
⑻Using additives in the same bath: Pay attention to the ionicity of the added additives and whether the pH is opposite (for example, do not mix anionic acrylic resin and cationic waterproofing agent). Melamine resin can be mixed with waterproofing agent, but be careful not to use it for a long time after preparation, because melamine resin will condense itself in the acidic waterproofing fluid, especially at high temperatures, which is one of the factors that causes roller sticking.
2. Main countermeasures
⑴ Set up a condensation circulating water pipe in the rolling tank or add ice packs to cool down;
⑵Add acid to adjust the pH of the working solution to 5-6.
⑶ Processed fabrics must be thoroughly washed and contain almost no alkali, dyes or additives.
⑷Add additives to improve the heat resistance and mechanical shear resistance stability of the working fluid.
AAASDFERHYTJTI
Disclaimer:
Disclaimer: Some of the texts, pictures, audios, and videos of some articles published on this site are from the Internet and do not represent the views of this site. The copyrights belong to the original authors. If you find that the information reproduced on this website infringes upon your rights, please contact us and we will change or delete it as soon as possible.
AA
