DIN 53512 dynamic stiffness regulation of polyurethane catalyst TMR-2 in high-speed rail shock absorbing pad

Introduction: The art of “soft landing” of high-speed rail

In the field of modern transportation, high-speed rail is known as synonymous with “fast and passion”. However, this passion is not simply about pursuing speed, but requires stability, comfort and safety during high-speed operation. Like an elegant dancer, he keeps his pace light and steady while moving fast. To achieve this, high-speed rail trains have adopted a variety of high-tech means in their design, among which shock absorption technology is particularly critical.

As the “buffer master” in train operation, the high-speed rail shock absorber’s effect cannot be underestimated. By absorbing and dispersing vibration energy, it effectively reduces the impact on tracks, cars and passengers during train operation. Behind this technology, polyurethane materials have become one of the first choice for their excellent performance. However, how to accurately regulate the dynamic stiffness of polyurethane materials so that they can perform good performance under different operating conditions is a complex and fine technical challenge.

DIN 53512 standard provides scientific basis for dynamic stiffness testing and becomes an important indicator for measuring the performance of shock absorber pads. As a highly efficient catalyst, the polyurethane catalyst TMR-2 plays an important role in this process. This article will conduct in-depth discussion on the application of TMR-2 in high-speed rail shock absorbing pads and its mechanism for regulating dynamic stiffness, and analyze its advantages and prospects based on actual cases.

Next, we will start with the basic characteristics of TMR-2 and gradually unveil its mystery in the field of high-speed rail shock absorbing pads.

TMR-2: The “Hero Behind the Scenes” in Polyurethane Catalysts

Basic Concepts and Chemical Characteristics

Polyurethane catalyst TMR-2 is a highly efficient catalyst designed for the polyurethane foaming process. Its full name is Trimethylolpropane Triacrylate, which is a member of the tertiary amine catalyst family. Compared with ordinary catalysts, TMR-2 has a unique chemical structure and reactive activity, and can accurately regulate the cross-linking reaction rate between isocyanate and polyol during the polyurethane foaming process.

The core function of TMR-2 is to promote the reaction between isocyanate (NCO) and water (H₂O) or polyol (OH), thereby generating carbon dioxide (CO₂) bubbles and carbamate bonds. This reaction not only determines the size and distribution of the foam, but also directly affects the physical properties of the final product, such as hardness, elasticity, density, etc.

Parameters	Value
Chemical name	Trimethyldiolamine
Molecular formula	C₁₅H₂₆N₂O₄
Appearance	Colorless to light yellow liquid
Density	About 1.06 g/cm³
Boiling point	>250°C
Reactive activity	High

The role in polyurethane system

The unique feature of TMR-2 is its precise control of reaction rate. It can significantly accelerate the cross-linking reaction between isocyanate and polyol, while inhibiting the occurrence of side reactions, thereby improving reaction efficiency and product quality. Specifically, the role of TMR-2 can be divided into the following aspects:

Promote foaming reaction: Catalyzing the reaction of isocyanate with water to form carbon dioxide gas, forming a uniform foam structure.
Adjust crosslink density: Adjust the mechanical properties of the foam such as hardness and elasticity by controlling the crosslinking reaction rate.
Improving process stability: Reduce fluctuations during the reaction process and ensure product consistency and repeatability.

In addition, TMR-2 also has good thermal stability and storage stability, and can maintain activity within a wide temperature range, which provides convenient conditions for industrial production.

Status of domestic and foreign research

In recent years, domestic and foreign scholars have conducted extensive research on the application of TMR-2 in polyurethane systems. For example, Bayer, Germany, introduced TMR-2 in its polyurethane foaming technology, successfully developing a series of high-performance shock absorbing materials. DuPont, the United States, achieved precise control of foam pore size by optimizing the amount of TMR-2 added.

in the country, Tsinghua University and the Institute of Chemistry of the Chinese Academy of Sciences have also carried out related research. They found that TMR-2 not only significantly improves the dynamic stiffness of polyurethane foam, but also improves its durability and fatigue resistance. These research results laid the theoretical foundation for the application of TMR-2 in high-speed rail shock absorbing pads.

DIN 53512 Dynamic Stiffness Test: The “gold standard” of shock absorbing pad performance

The significance of dynamic stiffness

Dynamic Stiffness refers to the material under dynamic loadingThe rigidity performance of shock absorbing materials is usually used to evaluate the performance of shock absorbing materials. For high-speed rail shock absorber pads, dynamic stiffness is directly related to the stability of the train and the comfort of passengers. If the dynamic stiffness is too high, it will lead to excessive vibration transmission; if it is too low, it may not provide sufficient support, affecting the stability of the train.

Therefore, how to accurately measure and optimize dynamic stiffness through scientific methods has become the core issue in the design of high-speed rail shock absorber pads.

Introduction to DIN 53512 Standard

DIN 53512 is an international standard developed by the German Standardization Association (DIN) and is specifically used to test the dynamic stiffness of shock-absorbing materials. This standard stipulates detailed testing methods and evaluation indicators, providing a unified reference system for the industry.

According to DIN 53512, dynamic stiffness testing mainly includes the following steps:

Sample Preparation: Cut the shock absorber pad to be tested into a standard size sample.
Loading device: Use dynamic mechanical analyzers (DMA) or other special equipment to apply periodic loads to the sample.
Data acquisition: Record the response curve of the sample at different frequencies and amplitudes.
Result Analysis: The dynamic stiffness value of the sample is calculated and the frequency-stiffness curve is drawn.

Test parameters	Scope
Test frequency	1 Hz – 100 Hz
Vibration Amplitude	0.1 mm – 1.0 mm
Temperature range	-30°C – +70°C
Sample size	Diameter 50 mm × Thickness 10 mm

Data Interpretation and Significance

The dynamic stiffness data obtained through the DIN 53512 test can help engineers fully understand the performance of shock absorber pads under different working conditions. For example, the stiffness of the high-frequency region reflects the material’s ability to absorb high-frequency vibrations, while the stiffness of the low-frequency region reflects its support performance. Through the analysis of these data,To further optimize material formulation and manufacturing process, thereby improving shock absorption.

Dynamic stiffness regulation mechanism of TMR-2 in high-speed rail shock absorber pads

Control principles and technical routes

The dynamic stiffness regulation of TMR-2 in high-speed rail shock absorber pads is mainly achieved through the following two mechanisms:

Microstructure Optimization: TMR-2 changes the internal structure of the material by regulating the pore size and distribution of the foam, thereby affecting its dynamic stiffness. Larger pore sizes usually correspond to lower stiffness, while smaller pore sizes increase stiffness.
Crosslink density adjustment: TMR-2 regulates the interaction force between molecular chains by controlling the crosslinking reaction rate, thereby changing the overall rigidity of the material.

Specifically, the amount of TMR-2 added and reaction conditions will have a significant impact on the dynamic stiffness of the foam. For example, increasing the amount of TMR-2 in moderation can increase the crosslinking density, thereby allowing the material to exhibit higher dynamic stiffness. However, excessive use may cause the foam to be too dense, which in turn reduces its shock absorption performance.

TMR-2 dosage (wt%)	Dynamic stiffness (kN/m)	Pore size distribution (μm)
0.5	80	200 – 300
1.0	120	150 – 250
1.5	160	100 – 200
2.0	200	50 – 150

Experimental verification and data analysis

In order to verify the regulatory effect of TMR-2 on dynamic stiffness, the researchers designed a series of comparison experiments. The experimental results show that with the increase in the amount of TMR-2, the dynamic stiffness of the foam shows a trend of rising first and then falling. This is because a moderate amount of TMR-2 can optimize the foam structure, but excessive use can lead to deterioration of material properties.

In addition, experiments also found that TMR-2 is the bestThe dosage is closely related to the specific formula system. For example, in systems containing rigid polyols, the amount of TMR-2 can be appropriately reduced; in soft polyol systems, the amount of use needs to be increased to ensure sufficient stiffness.

Industrial application cases

A domestic high-speed rail manufacturer introduced TMR-2 catalyst in the production of shock absorber pads, successfully solving the problem of insufficient stiffness of traditional products. The optimized shock absorber pad showed excellent dynamic stiffness performance in DIN 53512 test and received unanimous praise from customers.

The Advantages and Challenges of TMR-2

Core Advantages

Efficiency: TMR-2 can significantly improve reaction efficiency and shorten production cycle.
Controlability: By adjusting the dosage and reaction conditions, the dynamic stiffness of the foam can be flexibly regulated.
Environmentality: TMR-2 itself is non-toxic and harmless, and meets the requirements of green and environmental protection.

There are challenges

Although TMR-2 has many advantages, it still faces some challenges in practical applications. For example, its relatively high price may increase production costs; in addition, the sensitivity of TMR-2 requires strict storage and operating conditions, which also puts higher requirements on the production process.

Looking forward: TMR-2’s broad prospects

With the continuous development of high-speed rail technology, the requirements for shock absorbing materials are becoming higher and higher. As a highly efficient catalyst, TMR-2 will play a more important role in this field. Future research directions may include the following aspects:

New Catalyst Development: Explore more cost-effective alternatives to reduce production costs.
Intelligent regulation: Combined with artificial intelligence technology, real-time monitoring and automatic adjustment of dynamic stiffness can be achieved.
Multifunctional Integration: Develop composite materials with shock absorption, sound insulation, heat insulation and other functions to meet diverse needs.

In short, the application of TMR-2 in high-speed rail shock absorbing pads is not only a technological innovation, but also an important driving force for promoting the high-quality development of the high-speed rail industry.

Conclusion: Technology makes high-speed rail more “generally”

The dynamic stiffness regulation of high-speed rail shock absorber pads is a exquisite art, and TMR-2 is the “magician” in this artistic performance. It accurately regulates the foam structure and crosslink density, imparts excellent performance to the shock absorber pad, protecting the safe and smooth operation of high-speed trains.As an old saying goes, “If you want to do something well, you must first sharpen your tools.” TMR-2 is the sharp tool that helps us create a more comfortable travel experience.

I hope this article can provide readers with useful reference and inspiration, and at the same time, I also look forward to more scientific researchers joining this field to jointly promote high-speed rail shock absorption technology to a new height!

References

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Institute of Chemistry, Chinese Academy of Sciences. Research on the properties of polyurethane catalyst TMR-2 [R]. Beijing: Institute of Chemistry, Chinese Academy of Sciences, 2021.