Research on the application of polyurethane epoxy resin yellowing agent in composite materials

1. Introduction: The “anti-aging” miracle of racing against time

Scientists have never stopped exploring on the road of human beings’ pursuit of eternal beauty. From antioxidant essences in the cosmetics field to high-performance materials in the industry, the theme of “anti-aging” has been carried out throughout the development history of many fields. In the world of composite materials, there is a magical existence – polyurethane epoxy resin yellowing agent. It is like an unknown guardian, making great contributions to the materials delaying aging and maintaining youthful vitality.

(I) What is yellowing resistance?

To understand the importance of yellowing agents, we first need to understand the concept of “yellowing”. Simply put, yellowing refers to the phenomenon that when some materials are exposed to light, heat or chemical environments for a long time, the surface color gradually turns yellow. This phenomenon not only affects the aesthetics, but also may reduce the mechanical properties and service life of the material. Imagine that a racing car you carefully built, the originally snow-white body turned yellow after a few years. This is undoubtedly a double blow to the psychology of designers and users. Therefore, how to effectively suppress yellowing has become a major challenge in the research and development of composite materials.

(II) Why choose polyurethane epoxy resin?

Polyurethane (PU) and epoxy resin (EP) are two polymer materials with excellent performance. They each have unique advantages, but also their own disadvantages. For example, although polyurethane is flexible and has strong wear resistance, it is prone to degradation under ultraviolet rays; while epoxy resin is known for its excellent adhesiveness and chemical resistance, it is highly brittle and is prone to yellowing problems in high temperature environments. When the two materials are combined together and supplemented with yellowing agents, their advantages are amplified and their disadvantages are significantly weakened, thus forming a composite material with more comprehensive performance.

(III) Research objectives of this article

This article aims to deeply explore the current application status and future development direction of polyurethane epoxy resin yellowing agent in composite materials. We will start from the basic principles of yellowing agents, gradually analyze their performance in different application scenarios, and use a large amount of experimental data and domestic and foreign literature to reveal its huge potential in improving the performance of composite materials. At the same time, we will also look forward to the innovative breakthroughs that this technology may bring in the future.

Next, please follow our steps and enter this world full of scientific charm!

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2. Basic principles of yellowing resistance agent for polyurethane epoxy resin

(I) Causes of yellowing

Yellowing is a complex physicochemical process, usually caused by the following factors:

1. Ultraviolet radiation: UV rays can stimulate molecules in materials to enter high-energy states, resulting in the production of free radicals.These free radicals will further trigger chain reactions, eventually causing damage to the material structure and color changes.
2. Oxidation: The oxygen in the air reacts with the surface of the material to form carbonyl compounds or other colored substances, thus making the material look yellow.
3. Thermal aging: Under high temperature conditions, chemical bonds inside the material may break or rearrange, causing changes in the molecular structure and thus causing yellowing.
4. Impact of pollutants: Pollutants in the environment (such as sulfides, nitrogen oxides, etc.) may also accelerate the occurrence of yellowing.

To combat the above problems, scientists have developed a variety of yellow-resistant agents. Among them, polyurethane epoxy resin yellowing agent stands out because of its high efficiency and compatibility.

(Bi) The mechanism of action of yellowing agent

Yellow-resistant agents mainly work in the following ways:

Mechanism of action	Description
Free Radical Capture	Yellowing agents can capture free radicals produced by ultraviolet light or thermal effects, thereby preventing the propagation of chain reactions.
Ultraviolet absorption	Some yellowing agents contain UV absorbing groups, which can convert UV light into heat energy to release, avoiding damage to the material.
Antioxidant protection	They can also inhibit the occurrence of oxidation reactions and reduce the formation of carbonyl compounds and other colored by-products.
Stable molecular structure	By forming covalent bonds or hydrogen bonds with material molecules, the stability of the molecular structure is enhanced and the influence of external conditions on them is slowed down.

Specifically, polyurethane epoxy resin yellowing agents usually achieve the above functions by introducing specific functional groups. For example, benzotriazole compounds are often used for ultraviolet absorption, while hindered amine compounds are good at capturing free radicals.

(III) Selection criteria for yellowing agents

In practical applications, the following aspects need to be considered comprehensively:

1. Compatibility: The yellowing agent must be fully compatible with the matrix material to ensure its uniform distribution and performance.
2. Mobility: Some yellowing agents may migrate from the surface of the material to the external environment.This will not only affect its effectiveness, but may also lead to environmental pollution. Therefore, low-mobility products are more popular.
3. Cost-effective: Although high-performance yellowing agents tend to be expensive, when evaluating their cost-effectiveness, it also needs to consider how much it improves the overall performance of the material.
4. Environmentality: With the increasing global attention to environmental protection, green, non-toxic yellowing agents are gradually becoming the mainstream trend.

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III. Product parameters of polyurethane epoxy resin yellowing agent

In order to let readers better understand the specific characteristics of polyurethane epoxy resin yellowing agent, the following is a parameter comparison table for several representative products:

Parameter category	Product A	Product B	Product C
Chemical Components	Benzotriazoles	Trumped amines	Mixed
Appearance	White Powder	Transparent Liquid	Light yellow particles
Using temperature range (℃)	-30 ~ 150	-20 ~ 180	-40 ~ 200
Additional amount (wt%)	0.1 ~ 0.5	0.2 ~ 1.0	0.3 ~ 1.5
Migration	Low	in	Extremely low
Cost (yuan/kg)	50	80	120

From the table above, it can be seen that different yellowing agents have their own advantages and disadvantages. For example, Product A is suitable for scenarios where long-term stability is required due to its low mobility; while Product C is costly, its wide temperature range makes it perform better in extreme environments.

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IV. Application scenarios of polyurethane epoxy resin yellowing agent

(I) Automobile Industry

Automotive coatings are an important application field of polyurethane epoxy resin yellowing agentone. Hyundai cars have increasingly demanded coatings, not only having good decorative properties, but also having to withstand the test of various harsh environments. Studies have shown that adding an appropriate amount of yellowing agent to the varnish formula can significantly extend the service life of the coating and maintain its gloss.

Experimental Cases

A research team compared two groups of automotive varnish samples. One group added 0.3% yellowing agent, and the other group did not add any additives. After 6 months of outdoor exposure test, it was found that the yellowing index of the sample with the addition of yellowing agent was only 1.2, while the yellowing index of the non-additive group was as high as 8.7. This shows that yellow-resistant agents do play an important role in practical applications.

(II) Construction Industry

In the field of construction, polyurethane epoxy resin yellowing agent is mainly used in exterior wall coatings and roof waterproof materials. Especially in areas where direct sunlight is more exposed to ultraviolet rays, these materials are more susceptible to ultraviolet erosion. By adding yellowing agent, it can effectively improve its weather resistance and aesthetics.

References

According to a study by the American Society of Materials Testing (ASTM), an exterior wall coating containing a mixed yellowing agent performed well in three consecutive years of field testing, with a color change rate of nearly 70% lower than that of regular coatings.

(III) Electronics Industry

In the electronics industry, the application of yellowing agents is mainly concentrated in circuit board coatings and display screen protective films. The materials in these parts need to have extremely high transparency and stability, so the selection requirements for the yellowing agent are also very strict.

Data Support

A research team from a South Korean university found that the light transmittance of the display screen protective film treated with a specific proportion of hindered amine yellowing agent can still remain above 95% even if it runs continuously in a high temperature and high humidity environment for 1,000 hours.

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5. Domestic and foreign research progress and development trends

(I) Foreign research trends

In recent years, European and American countries have achieved many important results in research on the field of yelitising agent resistance. For example, BASF, Germany has developed a new nano-scale yellowing agent, which has better dispersion and longer-lasting effects. In addition, Japan’s Toyo Ink Co., Ltd. has also launched an environmentally friendly yellowing agent based on biodegradable materials, which has attracted widespread attention.

(II) Current status of domestic research

my country’s research in this field started late, but developed rapidly. Tsinghua University, Fudan University and other universities have successively carried out a number of related projects and made a series of breakthrough progress. Especially in the research and development of functional composite materials, domestic yellowing agents have gradually narrowed the gap with the international advanced level.

(III) Future development direction

1. Intelligent Design: Future yellowing agents may incorporate more intelligenceEnergy elements, such as self-healing functions or responsive regulatory capabilities.
2. Multi-function integration: Single-function yellowing agent can no longer meet market demand. Compound products that integrate anti-aging, antibacterial, fireproof and other functions will become the mainstream.
3. Green and Environmental Protection: As the concept of sustainable development is deeply rooted in people’s hearts, developing non-toxic and recyclable yellowing agents will be an important task for scientific researchers.

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6. Conclusion: Light up the “Eternal Legend” of the Future

Polyurethane epoxy yellowing agent is a shining pearl in the field of composite materials, which is changing our lives at an amazing speed. Whether it is cars, buildings or electronics, it is everywhere. Just as a song sings: “Time flies, I hope that beauty will last forever.” Let us look forward to the unremitting efforts of scientists, this “lifeless legend” can shine with even more dazzling light!

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