Will polyester hot melt turn yellow in a humid environment?

Will polyester hot melt turn yellow in a humid environment?
As a common synthetic fiber material, polyester hot melt is widely used in many industries. Before discussing whether polyester hot melt will turn yellow in a humid environment, we need to understand its chemical properties and structural characteristics.

Chemical properties of polyester hot melt
The main component of polyester hot melt is polyester polymer, a high molecular compound formed by terephthalic acid and ethylene glycol through ester exchange reaction. The ester bonds on the polyester molecular chain can absorb and release moisture, making polyester hot melt have good wet feel and hygroscopicity. In addition, the light resistance of polyester is second only to acrylic fiber, and the strength loss is only 60% after 600 hours of sunlight exposure, which is similar to cotton. Polyester is also strong in acid and solvent resistance, and has strong resistance to general non-polar organic solvents

Weather resistance of polyester hot melt
The weather resistance of polyester hot melt mainly depends on its molecular structure. Polyester has a strong absorption band in the 315 nm light wave region, so it has a certain stability under sunlight. This means that under normal sunlight exposure, polyester hot melt yarn is not prone to color change.

Color stability in humid environments
The color stability of polyester hot melt yarn in humid environments is mainly affected by its chemical structure and weather resistance. Since polyester has good chemical resistance and can resist the erosion of acids, alkalis and organic solvents, polyester hot melt yarn is not prone to color change, including yellowing, in general humid environments.

Factors affecting color change
Although polyester hot melt yarn has good weather resistance and chemical resistance, it may undergo a certain degree of color change under extreme conditions, such as long-term exposure to high temperature and humidity, strong sunlight or specific chemical environments. These changes may include fading, yellowing or discoloration, but usually require a longer exposure time to appear

Conclusion
In summary, polyester hot melt yarn is not easy to yellow under normal use and storage conditions, even in humid environments. Its chemical structure and weather resistance give polyester hot melt yarn good color stability. However, in order to ensure the color and performance of polyester thermal fuse yarn, it is recommended to avoid exposing it to extreme environmental conditions for a long time and take appropriate protective measures, such as storing it in a dry, dark place. Through reasonable use and maintenance, the service life of polyester thermal fuse yarn can be maximized and its original color and performance can be maintained.

Is the yellowing of polyester hot melt yarn in a humid environment a chemical reaction or a physical change?

The yellowing of polyester hot melt yarn in a humid environment involves both chemical reactions and physical changes, which can be analyzed from the following aspects:

1. Chemical reaction
The yellowing of polyester hot melt yarn may be related to the stability of its chemical structure in a humid environment. The ester group (-COO-) in the polyester molecule may undergo hydrolysis under high temperature or humid conditions, resulting in the breakage of the molecular chain, thus affecting its color and performance. This hydrolysis is a chemical reaction that will lead to a decrease in the performance and color change of polyester hot melt yarn.

2. Physical change
The yellowing of polyester hot melt yarn may also be related to physical changes. In a humid environment, polyester hot melt yarn may absorb moisture, resulting in changes in its internal structure, such as changes in the crystal structure. This change may not involve the breaking of chemical bonds, but will affect its optical properties, thereby causing color changes

3. Thermal migration
During the dry heat treatment process, polyester fibers dyed with disperse dyes will have a decrease in color fastness and color light variation, which is caused by the thermal migration of disperse dyes. The so-called thermal migration refers to the migration of part of the dye from the inside of the fiber to the surface of the fiber during the high-temperature treatment process after dyeing with disperse dyes. This migration may be more significant in a humid environment, causing the color of the polyester thermal melt to change.

4. Environmental factors
The light resistance of polyester is related to its molecular structure. It has a strong absorption band in the 315 nm light wave region, so the intensity only loses 60% after 600 hours of sunlight exposure, which is similar to cotton. However, in a humid environment, the combined effect of light and heat may accelerate the aging process of polyester thermal melt yarn, causing it to turn yellow.

5. Microbial effect
In a humid environment, the growth of microorganisms may also affect the color of polyester thermal melt yarn. Although polyester has good microbial resistance, under extreme conditions, the metabolites of microorganisms may react with polyester, resulting in color changes.

In summary, the yellowing of polyester thermal melt yarn in a humid environment is a complex process, which includes both chemical reactions, such as the hydrolysis of ester groups, and physical changes, such as changes in crystal structure and thermal migration of dyes. In order to maintain the color stability of polyester thermal melt yarn, it should be avoided from being exposed to high temperature and high humidity environment for a long time, and appropriate protective measures should be taken….

Can polyester hot melt yarn still be used after turning yellow in a humid environment?

Whether polyester hot melt yarn can still be used after turning yellow in a humid environment needs to be judged according to the cause and degree of yellowing. The following are some key factors and conclusions:

Chemical reaction: The yellowing of polyester hot melt yarn in a humid environment may be caused by chemical reaction. Polyester yellowing is generally caused by the addition of spinning or DTY oil in the spinning or stretching process to improve the bundling, flexibility and antistatic properties. The oil will turn yellow under the action of oxygen and ultraviolet rays, causing the fabric to turn yellow. This yellowing may be caused by chemical reactions. If the yellowing is serious, it may affect the structure and performance of polyester hot melt yarn, and it is not suitable for continued use.

Physical changes: The yellowing of polyester hot melt yarn may also be related to physical changes. In a humid environment, polyester hot melt yarn may absorb moisture, resulting in changes in its internal structure, such as changes in crystal structure. This change may not involve the breaking of chemical bonds, but it will affect its optical properties, causing color changes. If the yellowing is caused by physical changes and does not affect its basic performance, it may still be used.

Oxidation resistance: The oxidation resistance of polyester hot melt yarn is crucial to its performance in humid environments. If the polyester hot melt yarn has good oxidation resistance, it is less likely to turn yellow in a humid environment, and even if it turns yellow, it is unlikely to affect its performance

Anti-ultraviolet performance: The UV resistance of polyester hot melt yarn will also affect its color stability in a humid environment. If the polyester hot melt yarn has good UV resistance, it is less likely to turn yellow in a humid environment, and even if it turns yellow, it is unlikely to affect its performance

Treatment method: For polyester hot melt yarn that has turned yellow, some treatment methods can be taken to restore its performance. For example, the anti-yellowing performance of polyester yarn can be improved by adding anti-yellowing additives, which can prevent the polyester hot melt yarn from yellowing, improve its bonding strength, and reduce its melting point

In summary, whether the polyester hot melt yarn can still be used after turning yellow in a humid environment depends on the cause and degree of its yellowing. If the yellowing is caused by a chemical reaction and seriously affects the performance of the polyester hot melt yarn, it is not suitable to continue to use it. If the yellowing is caused by a physical change and does not affect its basic performance, it may still be used. In addition, the performance of the polyester hot melt yarn can be restored or improved by adding anti-yellowing additives.

How to restore the original color of polyester hot melt yarn after it turns yellow?

The treatment method of polyester hot melt yarn after it turns yellow in a humid environment can be restored to its original color through a specific chemical finishing process. The following are the treatment steps provided based on the search results:

1. Loosening and reversing
First, loosen the polyester yarn on the loose tube, and stop loosening the tube after the loose tube weight reaches 0.6kg to 1.0kg and the loose tube density is 0.2g/cm³ to 0.4g/cm³. Then transfer the polyester yarn on the loose tube to the dyeing tube

2. Cylinder loading and curing treatment
The dyeing tube with polyester yarn is loaded into the dyeing tank, and the anti-yellowing auxiliary solution is added to the dyeing tank. The solution includes water, anti-yellowing agent and acidic buffer, wherein the pH value of the anti-yellowing agent solution is 4-5, the bath ratio is 1:10 to 15, the amount of the anti-yellowing agent is 0.5% to 4.0%, the temperature in the tank is maintained at 15-25°C, and the time is 20-30 minutes

3. Washing and dehydration
Drain the anti-yellowing agent solution in the tank, add clean water for washing, and the bath ratio and temperature are the same as before. After washing, the material is loaded into the centrifuge for dehydration

4. Timed dehumidification
The dehydrated material is placed on the wire rack and enters the dehumidification room for dehumidification, and the moisture content of the yarn is controlled at 5-8%

5. Rewinding and inspection and packaging
The dried polyester yarn bobbins are rewound to the bobbins of the loom on the winding equipment, and then inspected and packaged

6. Selection of anti-yellowing additives
In this process, the anti-yellowing agent HJ-326GH of Guangzhou Hengjin Chemical Technology Co., Ltd. can be selected as an anti-yellowing additive. This product does not contain APEO, REACH EU regulations of high concern substances, does not contain free formaldehyde, organic halides and heavy metals, meets the OEKO-TEX 100 standard, and meets environmental protection requirements

Through the above process, the anti-yellowing performance of polyester hot melt yarn can be effectively improved, its original color can be restored, and its performance can be improved. This treatment method is suitable for white polyester, color-spun polyester and recycled polyester, and has a wide range of applications. In this way, even polyester thermofusible yarn that turns yellow in humid conditions can potentially be restored to a color close to its original state, thus extending its service life and maintaining its performance.