Polyurethane shoe material anti-yellowing agent: a secret weapon to keep winter boots bright
1. Introduction: Why do you need anti-yellowing agents?
In winter, a pair of warm and fashionable boots are a must-have item for many people in their wardrobe. However, careful friends may find that some beautiful white or light-colored boots will experience an embarrassing "yellowing" phenomenon after using them for a period of time. This phenomenon not only affects the appearance of the boots, but also may make people doubt whether the product quality is qualified.
So, why do the boots turn yellow? In fact, this is related to a chemical phenomenon called "yellow change". Simply put, yellowing refers to the process in which the material undergoes chemical reaction under external factors such as light, heat, and oxygen, causing the color to gradually turn yellow. This phenomenon is particularly obvious for polyurethane (PU) shoes. Because the PU molecular structure contains components that are easy to oxidize, yellowing is prone to occur when exposed to ultraviolet rays or high temperature environments for a long time.
To solve this problem, scientists invented a magical substance - polyurethane shoe cotton anti-yellowing agent. It is like an invisible guardian, which can effectively delay or even prevent the occurrence of yellowing, keeping our boots bright and new at all times. Next, let us understand the mystery of this magical substance together!
2. Basic principles of anti-yellowing agent for polyurethane shoe materials
To understand the mechanism of action of anti-yellowing agents, we need to start with the molecular structure of polyurethane materials. Polyurethane is a polymer compound produced by the reaction of isocyanate and polyols, and is widely used in shoe materials, furniture, automotive interiors and other fields. However, its molecular chain contains some unstable groups, such as carbonyl (C=O) and benzene ring structures, which are easily oxidized under ultraviolet irradiation or high temperature conditions, triggering a series of complex chemical reactions that eventually lead to yellowing of the material.
The working principle of anti-yellowing agent can be divided into the following aspects:
-
Absorb UV rays
Some components in anti-yellowing agents can absorb UV energy and convert it into harmless heat to release it, thereby avoiding the damage of UV light to polyurethane molecules. This function is similar to the protective effect of sunscreen on human skin. -
Catch free radicals
Free radicals are the main "culprit" during the oxidation process. Anti-yellowing agents inhibit the occurrence of yellowing by capturing these active free radicals, preventing them from further attacking the polyurethane molecules. -
Stable molecular structure
Certain anti-yellowing agents can also enhance the stability of their molecular structure by forming covalent or hydrogen bonds with polyurethane molecules and reducing chemical reversal caused by changes in the external environment.answer.
To illustrate this better, we can use a vivid metaphor: suppose that the polyurethane molecule is a castle, and ultraviolet and oxygen are enemies that are trying to invade. Without the anti-yellowing agent, the gates of the castle will be quickly broken, causing damage to the internal structure. But with the anti-yellowing agent, the castle has an additional layer of solid shields, which can effectively resist the enemy's attack and ensure the safety of the castle.
Table 1: Comparison of common anti-yellowing mechanisms
| Mechanism Type | Work Method | Pros | Disadvantages |
|---|---|---|---|
| Ultraviolet absorber | Absorbs ultraviolet rays and converts them into heat release | Efficiently prevent photoaging | May affect material transparency |
| Free Radical Capture | Catch and neutralize free radicals | Stop oxidation chain reaction | Required to be used with other antioxidants |
| Molecular Stabilizer | Enhance the stability of molecular structure | Improve overall weather resistance | The effect is slow and requires a long time to accumulate |
3. Detailed explanation of product parameters: Select a suitable anti-yellowing agent
There are many types of polyurethane shoe anti-yellowing agents available on the market, and the performance characteristics of each product are slightly different. The following is a detailed introduction to several common anti-yellowing agents and their key parameters:
1. UV-531 UV absorber
UV-531 is a highly efficient UV absorber, commonly used in light-colored or transparent polyurethane products. It has good thermal and light stability, and can significantly extend the service life of the material.
Parameter table
| parameter name | Value Range | Remarks |
|---|---|---|
| Appearance | White Powder | Easy to be dispersed |
| Melting point (℃) | 105-115 | Stable under high temperature environment |
| Large absorption wavelength (nm) | 340-380 | YesVisible light has basically no effect |
| Additional amount (wt%) | 0.3-0.8 | Adjust to specific needs |
2. BHT type radical capture agent
BHT (butylated hydroxyl group) is a classic free radical capture agent that is widely used in various polymer materials. It has strong oxidation resistance and is relatively inexpensive, but may have a slight impact on the color of the material.
Parameter table
| parameter name | Value Range | Remarks |
|---|---|---|
| Appearance | White crystalline powder | Easy soluble in organic solvents |
| Molecular Weight | 310.44 | Stable chemical properties |
| Large addition (wt%) | ≤1.0 | Excessive amount may lead to precipitation |
| Antioxidant efficacy | ≥90% | Under standard test conditions |
3. Bisphenol A type molecular stabilizer
Bisphenol A type stabilizer mainly improves the heat resistance and weather resistance of polyurethane by enhancing intermolecular forces. Although it has a slow effect, it has strong durability and is especially suitable for long-term use of shoe products.
Parameter table
| parameter name | Value Range | Remarks |
|---|---|---|
| Appearance | Transparent Liquid | Easy to mix |
| Density (g/cm³) | 1.18-1.20 | Measurement at room temperature |
| Heat resistance temperature (℃) | ≥150 | Excellent performance in high temperature environment |
| Recommended addition (wt%) | 0.5-1.0 | Adjust to formula requirements |
IV. Domestic and foreign research progress and application cases
In recent years, with the continuous improvement of consumers' requirements for product quality, the research and development and application of anti-yellowing agents have also made significant progress. The following are the new achievements of some domestic and foreign research institutions and enterprises:
1. Domestic research trends
A study from the Institute of Chemistry, Chinese Academy of Sciences shows that by combining nanotitanium dioxide with traditional ultraviolet absorbers, the anti-yellowing properties of polyurethane materials can be greatly improved. Experimental results show that the yellowing index of the modified materials has been reduced by more than 60% under simulated natural light conditions.
In addition, a chemical company in Zhejiang has developed a new multifunctional anti-yellowing agent. This product not only has excellent UV resistance, but also can improve the flexibility and wear resistance of the material at the same time. It has been successfully used in the production lines of many well-known shoe companies.
2. International cutting-edge technology
The "Uvinul series" anti-yellowing agent launched by BASF in Germany is considered one of the industry's benchmark products. Among them, Uvinul 405 is favored by many customers around the world for its excellent broad-spectrum absorption capacity and low volatility. According to data provided by the company, after a year of exposure to the sun outdoors with Uvinul 405, the yellowing level is only about 20% of the untreated samples.
DuPont, the United States, focuses on the development of environmentally friendly anti-yellowing agents. Its main product "Zeranol" uses renewable resources as raw materials, which not only ensures high performance but also conforms to the concept of green development. At present, this product has been adopted by many internationally renowned brands and is used to produce high-end sports shoes and casual shoes.
Table 2: Comparison of typical anti-yellowing agents at home and abroad
| Product Name | Manufacturer | Main Features | Application Fields |
|---|---|---|---|
| UV-531 | Japan Mitsui Chemistry | Efficient UV absorption | Light-colored shoes, transparent products |
| Uvinul 405 | BASF, Germany | Broad spectrum absorption, low volatility | Outdoor supplies, high-performance shoe materials |
| Zeranol | DuPont, USA | Environmental and renewable resources | High-end sneakers, luxury footwear |
| New Composite Materials | Chinese Academy of Sciences | Nanotropy, Multiple Functions | Industrial shoes, functional shoes |
5. Things to note in practical application
Although anti-yellowing agents perform well in improving the performance of shoes, the following points should still be noted in actual application:
-
Correct proportion
Different types of anti-yellowing agents have different requirements for dosage. Excessive addition may lead to degradation of material properties and even surface precipitation problems. Therefore, it is recommended to operate strictly in accordance with the recommended ratio provided by the supplier. -
Evening dispersion
Anti-yellowing agents must be fully dispersed into the polyurethane system to achieve good results. If the dispersion is uneven, it may cause local protection inadequate. -
Consider the effects of other additives
In the production of shoe materials, plasticizers, flame retardants and other additives are usually added. There may be interactions between these additives, so the effects of various factors should be fully evaluated when formulating. -
Storage Conditions
The anti-yellowing agent itself also needs to be properly stored to avoid moisture or exposure to strong light to ensure that its activity is not affected.
VI. Conclusion: Going towards a better future
The emergence of polyurethane shoe anti-yellowing agent has undoubtedly brought revolutionary changes to the winter boot manufacturing industry. It not only solves the yellowing problem that has plagued the industry for many years, but also provides designers with greater creative space, allowing more colorful and unique boots to be released.
Looking forward, with the continuous advancement of science and technology, I believe that the functions of anti-yellowing agents will become more and more powerful and their application scope will be wider. Perhaps one day, we no longer need to worry that any items will fade or age as time passes, and the world will become more colorful at that time!
Later, I borrow a classic line: "Technology changes life." I hope every reader can feel this big surprise brought by the small anti-yellowing agent!
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