Polyurethane TPE anti-yellowing agent optimizes color retention of outdoor furniture

Date：2025-03-16 Categories：News

Polyurethane TPE anti-yellowing agent: a secret weapon to keep outdoor furniture “youthful”

1. Introduction: The “shelf life” of colors and the challenges of outdoor furniture

On sunny days, we always like to move out a comfortable chair, make a cup of coffee, and enjoy a moment of tranquility in the courtyard. However, when we return to this familiar world again, we find that the once bright and dazzling outdoor furniture has become dull and even a layer of unpleasant yellow. This phenomenon not only destroys the aesthetics of the furniture, but may also affect its service life and functionality. So, what causes this problem? How to solve it?

The answer is actually very simple – ultraviolet (UV) radiation is one of the culprits. When outdoor furniture is exposed to sunlight, UV light gradually decomposes chemical bonds in the material, triggering a series of complex degradation reactions. These reactions will cause problems such as oxidation, fading and even aging on the surface of the material, and the common manifestation is “yellowing”. This is particularly prominent for furniture based on polyurethane thermoplastic elastomer (TPE).

To meet this challenge, scientists have developed a magical additive – polyurethane TPE anti-yellowing agent. It is like an invisible guardian, which can effectively delay or prevent damage caused to the material by ultraviolet rays, helping outdoor furniture maintain its original color and texture. This article will deeply explore the mechanism of action of this anti-yellowing agent from multiple perspectives such as principles, applications, and performance parameters, and analyze its outstanding performance in improving product weather resistance based on actual cases.

2. Basic principles of polyurethane TPE anti-yellowing agent

(I) What is yellowing?

Yellowing refers to the color change caused by changes in molecular structure of certain polymer materials under long-term exposure to specific environmental conditions (such as ultraviolet rays, oxygen, moisture, etc.). For polyurethane TPE, the main reasons for yellowing can be attributed to the following aspects:

Ultraviolet absorption: UV energy is high and can directly break chemical bonds in polymer chains.
Free Radical Generation: The broken molecule will produce free radicals, which will then crosslink or polymerize with other molecules.
Carbonyl compounds accumulation: As the reaction progresses, a large number of carbonyl compounds (such as aldehydes and ketones) will form inside the material, which often appear yellow or brown.

(II) How does anti-yellowing agent work?

The core task of anti-yellowing agents is to inhibit the occurrence of the above-mentioned processes through various chemical means. Specifically, it mainly achieves this goal in three ways:

Ultraviolet shielding
Anti-yellowing agents contain components that absorb UV light (such as hydroxybenzophenones), which form a barrier on the surface of the material, blocking most of the UV light from the outside and preventing it from entering the inside of the material.
Free Radical Capture
When UV light still inevitably penetrates the material, free radical scavengers in the anti-yellowing agents (such as hindered amine compounds) quickly capture and neutralize these highly active radicals, preventing them from further destroying the material structure.
Antioxidant protection
Anti-yellowing agents can also provide additional antioxidant functions, reducing carbonyl compounds generated by oxidation, thereby reducing the possibility of yellowing.

Through these triple protection mechanisms, the anti-yellowing agent successfully extends the “shelf life” of the polyurethane TPE material, allowing it to remain bright and new in harsh outdoor environments.

III. Types and characteristics of polyurethane TPE anti-yellowing agent

Depending on the chemical composition, the common polyurethane TPE anti-yellowing agents on the market can be roughly divided into the following categories:

Category	Main Ingredients	Features	Typical Application Scenarios
Hydroxybenzophenone	2-(2-hydroxy-5-methylphenyl)benzophenone	High absorption efficiency, suitable for light or transparent materials; but may slightly affect transparency	Outdoor lamps, decorative panels
Trumped amines	Tetramethylol derivatives	Strongly remove free radicals and good stability; suitable for dark colors or long-term use	High-end outdoor furniture, sports equipment shells
Benzotriazoles	2-(2′-hydroxy-5′-tert-octylphenyl)benzotriazole	Wide absorption wavelength range and strong weather resistance; less impact on the physical properties of the material	Automotive coatings, building films
Phosphate	Triphenyl Phosphite	It has both flame retardant and yellowing resistance; it is often used in products that require fire resistance	Industrial equipment housing and electronic component packaging materials

Each anti-yellowing agent has its unique advantages and limitations, so when choosing, you need to weigh the specific application scenario and needs. For example, if higher light transmittance is pursued, hydroxybenzophenones should be given priority; while if more attention is paid to the long-term durability of the product, hindered amines may be a better choice.

IV. Key performance parameters of polyurethane TPE anti-yellowing agent

To better evaluate the actual effect of anti-yellowing agents, we need to understand some key performance parameters. The following are several important indicators and their significance:

(I) UV absorption rate

Ultraviolet absorption rate refers to the ability of the anti-yellowing agent to absorb ultraviolet rays at a specific wavelength, which is usually expressed as a percentage. Generally speaking, the higher the absorption rate, the stronger the anti-yellowing performance. The following are the absorption rate data of several common anti-yellowing agents at different wavelengths:

Wavelength (nm)	Hydroxybenzophenones (%)	Trumped amines (%)	Benzotriazoles (%)
280	98	85	96
320	92	78	94
360	80	65	88

It can be seen from the table that hydroxybenzophenones exhibit extremely high absorption efficiency in the short-wave UV region, while benzotriazoles have good performance over the entire visible spectrum.

(Bi) Heat resistance

Heat resistance determines the stability of the anti-yellowing agent under high temperature conditions. This is especially important because many outdoor furniture may experience extreme temperature changes during use. The following is a comparison of the heat resistance properties of some anti-yellowing agents:

Category	High usage temperature (℃)	Thermal weight loss rate (%)
Hydroxybenzophenone	200	5
Trumped amines	250	3
Benzotriazoles	220	4

It can be seen that hindered amine anti-yellowing agents are excellent in heat resistance and can maintain high stability even under high temperature environments.

(III) Mobility

Mobility refers to whether the anti-yellowing agent gradually precipitates from the material over time, thereby reducing its efficacy. Lower migration means more lasting effects. The following are the mobility test results of several anti-yellowing agents:

Category	Migration Index (mg/m²)
Hydroxybenzophenone	12
Trumped amines	8
Benzotriazoles	10

Obviously, hindered amine anti-yellowing agents also have advantages in this regard and are very suitable for applications where long-term stability is required.

V. Practical application cases of polyurethane TPE anti-yellowing agent

(I) High-end outdoor seats

A high-end outdoor seat launched by a well-known brand uses polyurethane TPE material containing hindered amine anti-yellowing agent. After a two-year field test, the results showed that the seat could still maintain its original color under intense sunlight and frequent rain, without obvious yellowing or fading. In contrast, traditional polyurethane seats without the addition of anti-yellowing agents began to show macula in just half a year under the same conditions.

(II) Solar photovoltaic module

In the solar photovoltaic industry, polyurethane TPE is widely used as a sealing material in panel edge packaging. However, materials in traditional formulas are prone to yellowing after long-term exposure to sunlight, affecting overall aesthetics and heat dissipation performance. This problem has been significantly improved after the introduction of benzotriazole anti-yellowing agents, which not only improves the appearance quality of the components, but also extends its service life.

6. Progress in domestic and foreign research and future trends

In recent years, research on polyurethane TPE anti-yellowing agents has achieved many breakthrough results. For example, American scholar Johnson and others proposed a new composite anti-yellowing agent system. By mixing hydroxybenzophenones and hindered amines in a specific proportion, double protection against ultraviolet rays and free radicals is achieved, greatly improving the weather resistance of the material. In China, the team of the School of Materials Science and Engineering of Tsinghua University focuses on the development of natural planting based onThe environmentally friendly anti-yellowing agent of extracts strives to ensure performance while reducing the impact on the environment.

Looking forward, with the development of nanotechnology, more innovative anti-yellowing agents are expected to be released. For example, using nanotitanium dioxide as an ultraviolet absorber can not only improve absorption efficiency, but also impart additional antibacterial functions to the material. In addition, the research and development of intelligent anti-yellowing agents will also become a hot topic. This type of product can automatically adjust the protective strength according to changes in the external environment, thereby achieving optimal use results.

7. Conclusion: Keep color and keep beauty

Polyurethane TPE anti-yellowing agent is like a “sun protection clothing” on outdoor furniture, allowing it to always be rejuvenated no matter how much wind and sun it is exposed to. From basic principles to practical applications to cutting-edge research trends, we see the huge potential of this technology in promoting the development of the industry. Of course, no technology is perfect, and more exploration and innovation are needed in the future to further improve the functions of anti-yellowing agents. But no matter what, we should thank these little ones who work silently. It is their existence that makes our lives more colorful!

As an old proverb says, “Time can take away a lot of things, but true beauty will never fade.” For outdoor furniture, with the blessing of polyurethane TPE anti-yellowing agent, this sentence seems to become more authentic and credible.

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