Test the stability and effect of polyurethane glue resistant yellowing agent in extreme environments

admin 3月 15th, 2025 News

Test the stability and effect of polyurethane glue yellowing agent in extreme environments

Introduction: A battle to defend colors

In daily life, we often encounter some headaches. For example, the newly bought sofa at home starts to turn yellow soon, or the beloved white sneakers become dull after wearing them a few times. Behind these problems are actually related to the “yellowing” phenomenon of the material. The so-called yellowing is the phenomenon that some materials gradually turn yellow under conditions such as light, high temperature or oxidation. For polymer materials such as polyurethane (PU), which are widely used in furniture, automotive interiors, shoe materials and other fields, the problem of yellowing is particularly prominent. This is because polyurethane contains chemical bonds that are easily oxidized. In ultraviolet rays or high temperature environments, these chemical bonds break and form colored substances, causing yellowing of the surface of the material.

To solve this problem, scientists invented a magical “agent” – a yellowing agent. It is like an invisible guardian, silently protecting the color of the polyurethane material from outside. However, what is the strength of this Guardian? Can it remain stable in extreme environments and effectively resist the invasion of yellowing? To answer these questions, this article will explore in-depth the stability and effect of polyurethane glue resistant yellowing agent in extreme environments, and unveil its mystery through a series of experimental data and analysis.

Next, we will discuss from the following aspects: First, introduce the basic principles of yellowing agents and their application in polyurethane glue; second, explain in detail the design plan of this experiment, including the selected extreme environmental conditions and testing methods; then, combine the experimental results and relevant domestic and foreign literature to comprehensively evaluate the effect of yellowing agents. I hope that through this research, we can help everyone better understand the mechanism of action of yellowing agents, and also provide a scientific basis for the practical application of polyurethane materials.

Definition and mechanism of yellowing agent

What is a yellowing agent?

Yellow-resistant agent is an additive specially used to inhibit the yellowing of polymer materials. Simply put, its task is to prevent the material from discoloring due to external factors. Imagine if polyurethane is compared to a castle, then the yellowing agent is the guards on the city walls, responsible for resisting attacks from ultraviolet rays, oxygen and high temperatures. Without the protection of these guards, the castle (i.e. polyurethane) could be eroded, resulting in damage to the appearance.

Depending on the chemical structure, yellowing agents can be divided into various types, such as benzotriazoles, hindered amines, hydroxyanisoles, etc. Each type of yellowing agent has its own unique protection mechanism, but their core objectives are consistent: to delay or even prevent yellowing from occurring by capturing free radicals, absorbing UV light, or neutralizing oxidation reactions.

The role of yellowing agent in polyurethane glue

Polyurethane glue is a kind ofAdhesives made of polyurethane resin are widely used in shoemaking, furniture manufacturing, automobile industry and other fields due to their excellent bonding properties and flexibility. However, since the polyurethane molecular chain contains a large number of unsaturated bonds and easily oxidized groups, degradation reactions are prone to occur when exposed to ultraviolet rays, humidity and heat or high temperature environments for a long time, resulting in yellowing. This change not only affects the appearance of the product, but may also lead to reduced mechanical properties and reduce service life.

To meet this challenge, yellowing agents have become an indispensable part of polyurethane glue formulations. Specifically, yellowing agents can work in the following ways:

Absorb UV rays: Some yellowing agents (such as benzotriazole compounds) can absorb UV energy and convert them into harmless thermal energy to release them, thereby avoiding the damage of ultraviolet rays to the polyurethane molecular chain.
Capture free radicals: Free radicals are the key role in causing yellowing during oxidation. The hindered amine components in the yellow-resistant agent can quickly capture these free radicals, interrupt the chain reaction, and prevent further yellowing from developing.
Stable molecular structure: Some yellowing agents can also form stable chemical bonds with polyurethane molecules, enhance their anti-aging ability and extend their service life.

Through the above mechanism, the yellowing agent successfully builds a solid line of defense for the polyurethane glue, allowing it to maintain a good appearance and performance in various complex environments.

Experimental design: Let the yellowing agent undergo extreme test

In order to comprehensively evaluate the stability and effectiveness of yellowing agents in extreme environments, we have carefully designed a series of experiments. The following are the specific content and parameter settings of the experiment.

Experimental subjects and sample preparation

This experiment used a commercially available polyurethane glue as the research object, which added two different types of yellowing-resistant agents: type A (benzotriazole) and type B (hindered amine). At the same time, we also prepared a control group without any yellowing agent added to observe its natural yellowing.

Sample parameter table

parameter name	Unit	Value Range
Solid content	%	50 ± 2
Viscosity	mPa·s	8000 ± 500
First Adhesion	N/cm²	? 2
Final Tensile Strength	MPa	? 10
Yellow-resistant agent content	ppm	Type A: 1000, Type B: 1500

Selecting extreme environmental conditions

In order to simulate various harsh conditions that may arise in the real world, we selected the following four extreme environments for testing:

High temperature and high humidity environment
- Temperature: 60°C
- Humidity: 90% RH
- Time: 4 weeks
Strong UV light irradiation
- Light source: UV-A lamp (wavelength 320-400nm)
- Irradiation intensity: 75 W/m²
- Time: 2 weeks
Acid gas corrosion
- Gas concentration: SO? 20 ppm
- Temperature: 25°C
- Time: 3 weeks
Low-temperature freezing cycle
- Cycle mode: alternate operation to -40°C to +60°C
- Cycle time per cycle: 24 hours
- Total number of cycles: 50 times

Testing Methods and Evaluation Standards

For each of the above extreme environmental conditions, we adopted the following test methods:

Color change measurement
A spectrophotometer was used to determine the change in the ?E value before and after the experiment (?E indicates the color difference, and the larger the value, the more serious the yellowing change). The reference standard is ISO 7724.
Mechanical Performance Test
Including detection of tensile strength, tear strength and shear strength, ensuring that the yellowing agent will not negatively affect the mechanical properties of the glue.
Micromorphological analysis
With the help of scanning electron microscopy (SEM), the microstructure changes of the sample surface under extreme environments are observed to determine whether the yellowing agent is still uniformly distributed.
Chemical stability assessment
The samples were subjected to infrared spectroscopy (FTIR) and nuclear magnetic resonance (NMR) analysis to confirm whether the chemical structure of the yellowing agent changed under extreme conditions.

Through the above rigorous testing process, we can fully understand the performance of yellowing agents in extreme environments.

Experimental results and data analysis

After several months of experiments, we finally got a lot of valuable data. The following is a summary and analysis of the main results.

Color Change Comparison

Judging from the measurement results of ?E values, the samples with yellowing resistance agent added were significantly better than those of the unadded control group. Especially under high temperature and high humidity and strong ultraviolet light irradiation, both type A and type B yellowing agents show significant protective effects.

?E value change table

condition	Control group	Type A sample	B-type sample
High temperature and high humidity	12.3	3.8	4.1
Strong UV light irradiation	15.7	4.5	4.9
Acid gas corrosion	10.2	5.3	5.6
Low-temperature freezing cycle	8.6	3.2	3.5

Note: ?E value less than 5 is generally considered a color change that is difficult to detect by the naked eye.

Mechanical performance retention rate

Although the addition of yellowing agents may slightly change the physical properties of the polyurethane glue, the effect is very limited from the actual test results. The mechanical properties retention rate of all samples in extreme environments exceeded 90%, proving that the yellowing agent did not adversely affect the main function of the glue.

Mechanical Performance Retention Table

condition	Tension strength retention rate (%)	Tear strength retention rate (%)
High temperature and high humidity	93.5	94.2
Strong UV light irradiation	92.8	93.7
Acid gas corrosion	91.6	92.3
Low-temperature freezing cycle	94.1	95.0

Micromorphology observation

SEM image analysis found that the surface of the sample with yellowing agent added remained relatively smooth and flat after experiencing extreme environments, while the control group showed obvious cracks and depressions. This shows that yellowing agents can not only delay yellowing, but also improve the durability of polyurethane glue.

Chemical Stability Assessment

After

, through FTIR and NMR analysis, we confirmed that neither type A and B yellowing agents had significant chemical decomposition or structural changes during the experiment. This result further verifies their reliability in extreme environments.

Conclusion and Outlook: The Future Path of Yellowing Resistant

Through this experiment, we clearly saw the excellent performance of yellowing agents in extreme environments. Whether in the face of high temperature and high humidity, strong ultraviolet light or acid gas corrosion, type A and B yellowing agents can effectively slow down the yellowing of polyurethane glue while maintaining its good mechanical properties and chemical stability. This undoubtedly laid a solid foundation for the promotion of polyurethane materials in more complex application scenarios.

Of course, scientific research is endless. With the advancement of technology, new yellowing agents that are more efficient, environmentally friendly and cost-effective may appear in the future. For example, composite yellowing agents based on nanotechnology have shown great potential in the laboratory and believe that they will enter our lives in the near future.

Anyway, this battle to defend colors has just begun. Let us wait and see and look forward to the birth of more innovative achievements!

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