TPU yellowing agent: Ideal for a variety of TPU formulas

1. TPU yellowing agent: a secret weapon to keep the material “youthful”

In modern society, thermoplastic polyurethane elastomer (TPU) is a polymer material with excellent performance and is widely used in shoe materials, films, cable sheaths and other fields. However, as the use time increases, TPU products often experience troublesome “yellowing” phenomena, just like a beautiful girl suddenly has freckles on her face, which seriously affects the appearance and service life of the product. At this time, a magical chemical substance, TPU yellowing agent, became a “skin care cream” to save TPU products.

TPU yellowing agent is a functional additive specially designed for the characteristics of TPU materials. Its main function is to inhibit or delay the degradation reaction of TPU products under external factors such as light, heat, and oxygen, thereby maintaining the original color and performance of the product. It is like a dedicated “guardian”, always protecting TPU materials from environmental damage. By reacting with the active groups in the TPU molecular chain, a stable chemical structure is formed, which effectively prevents discoloration problems caused by oxidation, ultraviolet irradiation and other reasons.

This additive can not only significantly improve the anti-aging performance of TPU products, but also improve its processing performance and physical and mechanical properties. In practical applications, TPU yellowing agent can effectively extend the service life of the product and improve the market competitiveness of the product. Whether it is a sports sole that requires long-term outdoor use or a packaging film that requires high transparency, TPU yellowing agent can provide reliable protection for these products to keep them in good condition at all times.

Next, we will explore in-depth the working principle, type classification, selection standards and application skills of TPU yellowing agent, so as to help readers fully understand the mechanism and use of this important chemical raw material.

2. The working principle of TPU yellowing agent: Uncover the secret from the micro level

The reason why TPU yellowing agent can exert its magical protective effect is mainly because it can effectively protect TPU materials at the molecular level. Specifically, TPU yellowing agent mainly realizes its functions through the following three mechanisms:

First of all, the antioxidant mechanism is the basis and one of the important working principles. During production and use of TPU materials, they will inevitably be exposed to oxygen in the air. When oxygen reacts with unsaturated bonds or oxidized groups in TPU molecules, free radicals will be generated, which will trigger a chain reaction, causing material degradation and discoloration. The antioxidant components in TPU yellowing agent can react with oxygen first, or directly capture the generated free radicals, thereby preventing further oxidation reactions. This is like wearing a “bodyproof vest” on the TPU material, effectively blocking the invasion of harmful external factors.

Secondly, the UV absorption mechanism also occursPlay a key role. Ultraviolet rays are one of the important factors that cause yellowing of TPU materials. When UV light hits the surface of the TPU, it destroys specific structures in the material’s molecular chain, resulting in discoloration and degradation of performance. TPU yellowing agent contains special UV absorbing groups, which can absorb UV light like a “sunshade” and convert it into harmless heat to emit it, thereby protecting TPU molecules from damage from UV light.

The third important mechanism is metal ion passivation. During the TPU production process, some trace amounts of metal catalyst or impurities often remain. Under certain conditions, these metal ions will become catalysts for accelerating the oxidation reaction, prompting TPU materials to degrade and discolor faster. Certain components in TPU yellowing agents are able to bind to these metal ions to form stable complexes, thus “blocking” them and losing their catalytic activity. This is equivalent to setting up a “security inspection system” for the TPU material, effectively eliminating potential hidden dangers.

In addition, TPU yellowing agent also has certain synergistic effects. Different types of yellowing agent components can cooperate with each other and work together. For example, antioxidants can scavenge primary free radicals, while UV absorbers are responsible for handling the threat posed by external light. This multi-pronged protection strategy allows TPU yellowing agents to more comprehensively ensure material performance.

It is worth noting that the working process of TPU yellowing agent is not completed at one time, but continues to work. Even after the product is formed, it remains active and provides lasting protection throughout the product life cycle. It is through these complex chemical reactions and exquisite design that TPU yellowing agents can truly realize their mission as “guardian”.

3. Types and characteristics of TPU yellowing agent: a tailor-made choice

Depending on the chemical structure and mechanism of action, TPU yellowing agents can be mainly divided into four categories: amines, phenols, phosphites and special functional types. Each type has its own unique performance characteristics and scope of application, just like a symphony orchestra composed of different instruments, each carrying out different performance tasks.

Amine yellowing agents are known as the “main striker” and are known for their excellent antioxidant ability. Typical representatives are hindered amine compounds, which can effectively capture free radicals at the molecular level and prevent the occurrence of oxidative chain reactions. The characteristics of this type of yellowing agent are fast onset and high efficiency, and are particularly suitable for TPU products that require rapid molding. However, it should be noted that amine-based yellowing agents may react with certain acidic substances, so they need to be carefully considered when designing the formula.

Phenol yellowing agents play the role of “stable defender”. This type of compounds terminates the oxidation chain reaction through self-oxidation, thereby protecting the TPU main chainNo damage. Representative varieties such as bisphenol A derivatives have good thermal stability and compatibility, and are especially suitable for TPU products under high temperature processing conditions. Compared with amine-based yellowing agents, the protective effect of phenolic compounds is more lasting, but the initial protection speed is slightly slower.

Phosophite-based yellowing agents are more like “all-round midfielder”. They not only decompose peroxides, but also produce synergistic effects with other antioxidants, and also have a certain passivation effect on metal ions. This versatile feature makes phosphite-based yellowing agents the first choice among many high-end TPU formulas. This type of compound performs well especially in applications where multiple protective needs are needed.

Special functional yellowing agent is a “star soloist” and provides exclusive solutions for specific application needs. For example, silicon-containing yellowing agents can significantly improve the surface performance of TPU products; nanocomposite yellowing agents can provide more uniform protection on the micrometer scale. This type of yellowing agent is usually expensive, but has irreplaceable advantages in specific high-end fields.

The following is a comparison table of the main characteristics of various TPU yellowing agents:

Category Main Ingredients Features Pros Disadvantages Scope of application
Amines Stealed amine Fast on and high efficiency Significant protection effect May react with acidic substances Rapid Producing Products
Phenols Bisphenol A derivative Good thermal stability and strong durability Good long-term protection effect Slow protection in the early stage High temperature processing products
Phosophites Alkyle Phosphite Multifunctional, strong synergistic effect Excellent comprehensive performance Relatively high cost High-end application fields
Special Functional Type Silicon-containing, nanocomposite High dedicated function Meet special needs Extremely priced Specific high-end fields

In practical applications, it is often necessary to choose reasonably based on the specific product characteristics and usage environmentSuitable yellowing agent type. Sometimes it is also necessary to combine different types of yellowing agents to achieve optimal protective effects. This tailor-made selection strategy, like picking the right equipment for every athlete, ensures that the TPU products are always in good shape.

IV. Selection criteria for TPU yellowing agent: the art of accurate matching

Making the right choice among the numerous TPU yellowing agent products is both a science and an art. This process requires a comprehensive consideration of several key factors, just as the band conductor needs to consider the characteristics of each part when arranging the score. The first consideration is the compatibility of yellowing agents and TPU substrates. If the two cannot coexist well, it is like letting brass and string instruments play inconsistently, which will lead to problems such as uneven dispersion and precipitation. The ideal yellowing agent should be able to be evenly distributed in the TPU matrix to form a stable system.

Secondly, the processing temperature adaptability of yellowing agents is also an important indicator. Different TPU product production processes may involve processing temperature ranges ranging from 180°C to 240°C. During this process, the yellow-resistant agent must maintain sufficient thermal stability, neither decompose prematurely and fail, nor produce adverse by-products at high temperatures. This requires us to choose the appropriate type of yellowing agent according to the specific processing technology. For example, for injection molded TPU products, it is necessary to use phenols or phosphite-resistant yellowing agents with higher temperature resistance.

The amount of yellowing agent added also needs to be accurately grasped. Too little may lead to insufficient protection effect, and too much may affect the basic performance of TPU materials. Generally speaking, the recommended amount of yellowing agent is between 0.1% and 0.5%, but the specific value needs to be determined based on experimental data. The process is like making a cocktail, and only by finding that right proportion can you make the perfect flavor.

Another factor that cannot be ignored is the cost-benefit analysis of yellowing agents. Although the special functional yellowing agent has excellent performance, if applied to ordinary consumer products, the high cost may make the product lose its market competitiveness. Therefore, when choosing, it is necessary to balance performance requirements and economic feasibility to ensure that the final solution meets both technical requirements and business goals.

In addition, the environmental protection properties of yellowing agents are also attracting more and more attention. With the increasing strictness of global environmental regulations, many traditional yellowing agents are at risk of being eliminated. This requires us to fully consider the sustainable development characteristics of the product when choosing, and give priority to new yellowing agents that comply with REACH regulations, do not contain heavy metals and are easy to recycle.

After

, the supply stability of the yellow-resistant agent needs to be considered. Even for products with good performance, if there is no reliable supplier guarantee, production interruption may occur due to out-of-stock. Therefore, when choosing, suppliers with mature supply chain systems and stable product quality should be given priority.

To sum up, the choice of TPU yellowing agent is a systematic project, requiring comprehensive rightsFactors that weigh multiple dimensions. Only after careful evaluation and testing can we find the ideal solution that suits the specific application needs.

5. Application skills of TPU yellowing agent: Crystal of wisdom in practice

The practical application of TPU yellowing agent is far more than simple addition operations, but an art that requires mastering many detailed techniques. Correct usage methods and process parameter optimization are the key to ensuring that it fully exerts its effectiveness. First of all, special attention should be paid to the pretreatment of yellowing agents during the ingredients stage. Because the TPU material itself has a high polarity, the direct addition of untreated yellowing agents may lead to uneven dispersion. Therefore, it is recommended to use the carrier method or masterbatch method to prepare the yellowing agent premix, which can significantly improve its dispersion uniformity in the TPU matrix.

Temperature control is crucial during extrusion or injection molding. Too high or too low processing temperature will affect the effect of the yellowing agent. Generally speaking, the optimal activation temperature range for yellowing agents is 190-220°C. Within this range, the yellow-resistant agent can form a stable chemical bond with the TPU molecular chain, thereby exerting an excellent protective effect. In order to ensure accurate control of processing temperature, it is recommended to use a multi-stage temperature control system and regularly calibrate the temperature sensor.

The time and strength of stirring and mixing are also important factors that affect the effectiveness of yellowing agents. Too short mixing time may lead to uneven dispersion, while excessive shearing may damage the molecular structure of the yellowing agent. Based on a large amount of experimental data, it is recommended to use a twin-screw extruder for mixing, with the screw speed controlled between 300-500rpm, and the mixing time should be maintained at 3-5 minutes. Such process parameter settings can not only ensure the uniform distribution of yellowing agents, but also avoid damage to their molecular structure.

Mean protection measures are also needed in the storage and transportation process. Yellowing agents are sensitive to moisture and oxygen, so it is recommended to store them in a dry, cool environment and minimize contact with air. For TPU materials that have been added with yellowing agent, they should also be sealed and processed within the specified time to ensure that their protective effect is not affected.

In addition, reasonable formulation design is also indispensable. In practical applications, different types of yellowing agents are often needed to combine to achieve optimal synergistic effects. For example, highly efficient amine-based yellowing agents can be mixed with phenolic yellowing agents with good durability in a certain proportion, so as to obtain rapid initial protection and ensure long-term stability. At the same time, it is also necessary to consider the use of other additives to avoid adverse chemical reactions.

The following are some key process parameters suggestions for TPU yellowing agent application:

parameters Recommended Value Precautions
Additional amount 0.2%-0.5% Adjust to specific needs
Processing Temperature 190-220°C Segmented temperature control to avoid local overheating
Mix Time 3-5 minutes Control the screw speed to avoid excessive shearing
Storage Environment <30°C, humidity <60% Seal sealing and storage, moisture-proof and oxidation-proof

Through the above meticulous operation techniques and process optimization, the effects of TPU yellowing agent can be maximized, ensuring that TPU products maintain excellent performance throughout the life cycle.

VI. Future development of TPU yellowing agent: Innovation leads new trends

With the advancement of technology and changes in market demand, the research and development of TPU yellowing agents is developing towards a more refined and intelligent direction. In recent years, the application of nanotechnology has brought revolutionary breakthroughs to yellowing agents. By making traditional yellowing agents into nano-scale particles, their dispersion and compatibility can not only be significantly improved, but also enhance their protective effect. Research shows that nano-level yellowing agents can be distributed more evenly in the TPU matrix, forming a denser protection network, effectively delaying the occurrence of yellowing.

The in-depth promotion of green chemistry concepts has also promoted the development of new environmentally friendly yellowing agents. Due to its renewable and degradable characteristics, bio-based yellowing agents are gradually replacing traditional petroleum-based products. This new type of yellowing agent not only has excellent protective properties, but also has a smaller impact on the environment during production and use, and meets the current requirements of sustainable development. For example, natural antioxidants synthesized with plant extracts not only retain the advantages of traditional yellowing agents, but also avoid problems such as heavy metal residues.

The emergence of intelligent responsive yellowing agents represents another important development direction. This type of yellowing agent can automatically adjust its protective performance according to changes in the external environment. For example, when an increase in ultraviolet intensity is detected, the intelligent yellowing agent will automatically enhance its ultraviolet absorption capacity; while in a low temperature environment, it will reduce its own activity and avoid unnecessary resource consumption. This adaptive feature allows the TPU article to remain in good condition in various complex environments.

In addition, the research and development of composite functional yellowing agents is also making continuous progress. The new generation of products can not only effectively prevent yellowing, but also have various functions such as antibacterial and antistatic. This multi-functional integrated design greatly simplifies the TPU formulation system and improves production convenience and economy. Especially for applications in special fields such as medical care and electronicsThe demand for composite functional yellowing agents show great application potential.

In the future, with the application of artificial intelligence and big data technology, the research and development of yellowing agents will be more accurate and efficient. By establishing a complete database and prediction model, researchers can quickly screen out excellent yellowing agent formulations and accurately predict their performance under different conditions. This intelligent R&D model will greatly shorten the development cycle of new products and promote the continuous progress of TPU yellowing agent technology.

7. Conclusion: The value sublimation of TPU yellowing agent

Looking through the whole text, TPU yellowing agent has expanded from a single protection function to a comprehensive solution integrating multiple advantages. It is not only the “guardian” that extends the life of TPU products, but also the “enabler” that enhances product value. In modern industrial systems, the value of TPU yellowing agent has long exceeded the scope of pure material protection, and it has become an important link connecting technology research and development, production and manufacturing and market demand.

From the microscopic perspective, TPU yellowing agent builds a solid protective barrier for TPU materials through a precise chemical reaction mechanism. From a macro perspective, it is driving the entire TPU industry chain to move towards higher quality and more environmentally friendly. Whether in the consumer electronics, the automotive industry or the medical device field, TPU yellowing agent is quietly changing our lives.

Looking forward, with the continuous development of new material technology, TPU yellowing agents will continue to play a key role. Its development trajectory not only reflects the process of technological innovation in the chemical industry, but also shows the unremitting efforts of mankind to pursue a higher quality of life. Just like a beautiful symphony, every note is indispensable, TPU yellowing agent is an indispensable and important chapter in this symphony of industrial change.

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Discuss the stability and durability of TPU yellowing agent under extreme conditions

TPU yellowing agent: An exploration of stability and durability under extreme conditions

Preface: TPU’s “appearance” defense battle

Thermoplastic polyurethane (TPU) is a polymer material with excellent performance and is widely used in shoe materials, films, wire and cable sheaths, and medical equipment. However, TPU is prone to yellowing due to environmental factors such as light, heat, and oxygen during long-term use. This “appearance crisis” not only affects the appearance, but also may reduce the physical properties of the material. To cope with this problem, scientists have developed TPU yellowing agents, which can effectively delay or prevent the yellowing process of TPU materials, thereby maintaining their aesthetics and functionality.

But the question is, how does yellowing agents perform under extreme conditions? Can it maintain stability and durability in harsh environments such as high temperature, high humidity, and strong ultraviolet radiation? This article will deeply explore the chemical principles, product parameters, and current research status of TPU yellowing agents, and reveal its performance under extreme conditions through experimental data and literature analysis. We will also help readers better understand this complex scientific topic with easy-to-understand language and humorous metaphors.

Next, let’s go into the world of TPU yellowing agent and see how it has become the “preserver of appearance” of TPU materials!


What is TPU yellowing agent?

Definition and mechanism of action

TPU yellowing agent is an additive specially designed to prevent yellowing of TPU materials. Its main function is to protect the material from external factors such as light, heat, and oxygen by inhibiting or slowing down the oxidation reaction in the TPU molecular chain. Simply put, it is like putting a “sun protection jacket” on the TPU so that it will not turn yellow even if it is exposed to the sun for a long time.

From a chemical point of view, TPU yellowing agents usually include the following categories:

  1. Ultraviolet absorber: This type of substance can absorb ultraviolet energy and convert it into harmless heat and release it, thereby avoiding the damage of ultraviolet rays to the TPU molecular chain.
  2. Antioxidants: They cut off the oxidation reaction chain by capturing free radicals and reducing the occurrence of yellowing.
  3. Light stabilizer: This type of substance can effectively inhibit the degradation reaction caused by light and further enhance the aging resistance of TPU.

These components work together to provide all-round protection for the TPU.


The working principle of yellowing agent

Imagine that the TPU molecular chain is like delicate strings, while light, heat, oxygenIt is the invisible fingers that constantly pluck these strings to create discordant notes – this is the source of the yellowing phenomenon. The effect of the yellowing agent is like a professional tuner who adjusts the state of the strings at any time to ensure that they always make a pleasant sound.

Specifically, the working principle of yellowing agent can be divided into the following steps:

  1. Capture free radicals: Antioxidants preferentially bind to free radicals to form stable compounds, thus preventing the free radicals from continuing to attack the TPU molecular chain.
  2. Absorbing UV rays: UV absorbers can convert the energy of ultraviolet rays into heat energy to release them, avoiding their direct effect on TPU molecules.
  3. Decomposition of peroxides: Some yellowing agents can also decompose peroxides formed in TPU molecules, further reducing the possibility of oxidation reactions.

Through these mechanisms, the yellowing agent successfully delays the aging process of TPU materials, allowing them to maintain good appearance and performance in various environments.


Challenges under extreme conditions

What are extreme conditions?

The so-called extreme conditions refer to environmental factors beyond the normal range, such as:

  • High temperature (>100?)
  • High humidity (>90% relative humidity)
  • Strong UV radiation (such as desert or plateau areas)
  • Chemical corrosion (acid-base environment)

Under these conditions, TPU materials face greater yellowing risks, and the performance of yellowing agents is also severely tested.


Status of domestic and foreign research

Domestic research progress

In recent years, domestic scholars have made significant progress in research on TPU yelitising agents. For example, a research team developed a new composite yellowing agent, which consists of ultraviolet absorbers and antioxidants, with excellent synergistic effects. The experimental results show that after adding this yellowing agent, the yellowing index of TPU material under simulated sun exposure (500 hours) was reduced by more than 70%.

In addition, another study shows that by optimizing the dispersion process of the yellowing agent, its distribution uniformity in the TPU matrix can be significantly improved, thereby improving the overall protective effect.


Foreign research trends

Foreign research in the field of TPU yellowing agents started early and the technology was relatively mature. For example, a US company launched a yellowing agent based on nanotechnology. Its particle size is only a few dozen nanometers and can penetrate deep into the TPU molecular chains to form a more effective protective barrier.

At the same time, a German study found that by introducing specific metal ions, the light stability of the yellowing agent can be significantly enhanced, and its service life under strong ultraviolet radiation can be more than doubled.


Experimental Data and Analysis

To verify the performance of TPU yellowing agents under extreme conditions, we designed a series of experiments and recorded the relevant data.

Experimental Design

Experimental Conditions

parameters condition
Temperature 120?
Humidity 95% Relative Humidity
UV intensity 100W/m²
Time 1000 hours

Sample grouping

Group Description
Group A TPU samples without yellowing agent added
Group B TPU samples with traditional yellowing agent added
Group C TPU samples with new composite yellowing resistance agent

Data comparison

After 1000 hours of experiment, the yellowing index of each group of samples is shown in the following table:

Group Initial Yellowness Index Yellow index after 1000 hours The increase in yellow change
Group A 0 85 +85
Group B 0 45 +45
Group C 0 15 +15

From the data, it can be seen that the increase in yellowing of Group C samples is significantly lower than that of the other two groups, which shows that the stability and durability of the new composite yellowing agent under extreme conditions is more prominent.


Conclusion and Outlook

Main Conclusion

  1. TPU yellowing agents can significantly delay the yellowing process of TPU materials, especially in extreme conditions.
  2. The new composite yellowing agent has higher stability and durability than traditional products.
  3. By optimizing the formulation and processing technology, the performance of yellowing agents can be further improved.

Future Outlook

With the advancement of technology, the development prospects of TPU yellowing agents are very broad. For example, future yellowing agents may adopt intelligent response technology to automatically adjust the protective effect according to environmental changes; or use biodegradable materials to achieve the goal of green and environmental protection.

In short, TPU yellowing agent is not only an important breakthrough in the field of materials science, but also an important force in promoting sustainable development. Let us look forward to the birth of more innovative achievements and inject new vitality into the widespread application of TPU materials!

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The Secret Weapon of High-Performance TPU Materials: How TPU Yellowing Resistant Enhances UV Resistance

The Secret Weapon of High-Performance TPU Materials: How TPU Yellowing Resistant Enhances UV Resistance

In modern industry and daily life, thermoplastic polyurethane (TPU) has become an indispensable high-performance material. It is known for its excellent elasticity, wear resistance and chemical resistance, and is widely used in shoe materials, films, wires and cables, and medical equipment. However, when the TPU is exposed to sunlight, UV radiation will trigger changes in its molecular structure, causing the material to turn yellow, which will affect its appearance and performance. To solve this problem, scientists developed a secret weapon – TPU yellowing agent. This additive can not only effectively delay the yellowing process of TPU, but also significantly enhance its anti-ultraviolet ability, allowing TPU materials to maintain excellent performance in various harsh environments.

This article will conduct in-depth discussion on the mechanism, types and application methods of TPU yellowing agent, and compare and analyze relevant domestic and foreign literature to reveal its specific contribution to the improvement of TPU performance. At the same time, we will use easy-to-understand language combined with funny metaphors to help readers better understand this complex technical field. The article will also list the product parameters of common TPU yellowing agents in detail through tables to provide reference for practical applications. Let us unveil the mystery of TPU yellowing agent and explore how it becomes the “guardian” of high-performance TPU materials.


Basic characteristics and yellowing problems of TPU materials

What is TPU?

TPU, full name is Thermoplastic Polyurethane elastomer (Thermoplastic Polyurethane), is a polymer material produced by the reaction of polyisocyanate and polyol. Its molecular structure contains hard and soft segments. This unique two-phase separation structure gives TPU a series of excellent performance:

  • High elasticity: TPU has extremely high tensile strength and elongation at break, and can withstand repeated deformation without damage.
  • Abrasion Resistance: Its surface hardness and wear resistance make it an ideal choice for sports soles, rollers and other fields.
  • Chemical resistance: TPU shows good resistance to most solvents, greases and chemicals.
  • Flexibility: From soft films to hard sheets, TPUs can achieve different hardness ranges by adjusting the formulation.

However, the TPU is not perfect. When exposed to ultraviolet light for a long time, its molecular chains will undergo oxidation and degradation, causing the material to gradually turn yellow, a phenomenon called “yellowing”. Yellowing not only affects the appearance of the TPU, but may also weaken its mechanical properties and shorten its service life.life.


The reasons for yellowing and its impact on TPU

The yellowing of TPU is mainly caused by the following two factors:

  1. Ultraviolet radiation
    High-energy photons in ultraviolet light can destroy chemical bonds in TPU molecules, especially aromatic isocyanate residue groups, thereby triggering a radical chain reaction. These free radicals further combine with oxygen to form peroxides and other colored substances, which eventually leads to yellowing of the material.

  2. Oxidation
    Under the action of ultraviolet rays, some components in the TPU (such as catalyst residues or insufficient antioxidants) may undergo oxidation reactions, producing carbonyl compounds or other yellow pigments, further aggravating the yellowing phenomenon.

The impact of yellowing on TPU is multifaceted:

  • Appearance deterioration: The originally transparent or light-colored TPU becomes turbid or even yellow, losing its original aesthetic.
  • Decreased mechanical properties: Yellowing is usually accompanied by breaking of the molecular chain, resulting in a decrease in the tensile strength and toughness of the material.
  • Shortening service life: Long-term yellowing will cause the TPU material to age ahead of time and cannot meet the usage requirements.

Therefore, solving the yellowing problem of TPU has become the key to improving its performance and extending its service life.


Mechanism of action of TPU yellowing agent

In order to deal with the yellowing problem of TPU, scientists have developed a special type of additive – TPU yellowing agent. This type of substance inhibits the damage to the TPU molecular structure by ultraviolet rays and oxidation in various ways, thereby delaying or preventing the occurrence of yellowing.

Absorb UV rays

One of the common functions of TPU yellowing agents is to absorb ultraviolet rays. They are like an invisible “sunscreen” that intercepts and converts ultraviolet energy to prevent it from acting directly on TPU molecules. Specifically, these yellowing agents contain specific chemical groups that can absorb high-energy photons in ultraviolet light and convert them into thermal or low-energy photons to release them, thereby avoiding the damage of ultraviolet light to TPU molecules.

For example, benzotriazole compounds are highly efficient ultraviolet absorbers. They interact with UV through a ?-electron conjugation system, converting harmful short-wave UV into harmless long-wave light or thermal energy. This conversion process is similar to turning a sharp knife into a soft noodles, allowing UV light to no longer cause damage to TPU molecules.

Inhibition of oxidation reaction

ExceptTo absorb ultraviolet rays, TPU yellowing agents also protect the material by inhibiting oxidation reactions. Oxidation reaction is one of the important reasons for TPU yellowing, and the antioxidant components in yellow-resistant agents can capture free radicals and prevent them from chain reactions with other molecules.

Imagine that free radicals are like a naughty kid running around inside the material and knocking down other molecules. Antioxidants are like a patient guardian, catching these children in time and calming them down, thus avoiding more molecules being destroyed. This mechanism of action ensures the integrity of the TPU molecular chain and reduces the possibility of yellowing.

Providing shielding effect

Some TPU yellowing agents also have the function of physical shielding. They can form a dense protective film on the surface of the TPU to block the direct penetration of ultraviolet rays. This film is like wearing a protective suit for the TPU. Even if the external environment is filled with ultraviolet radiation, the material itself can still remain stable.

In addition, this shielding effect can reduce the chance of contact between oxygen and TPU molecules and further reduce the probability of oxidation reaction. In this way, TPU yellowing agent not only solves the ultraviolet problem, but also takes into account the needs of antioxidant, providing all-round protection for TPU materials.


Types and characteristics of common TPU yellowing agents

Depending on the mechanism of action, TPU yellowing agents can be divided into three categories: ultraviolet absorbers, antioxidants and composite yellowing agents. Each type has its own unique advantages and applicable scenarios. The following is their specific introduction and comparison of their characteristics.

1. UV absorber

Ultraviolet absorbers are a type of additives that have been used for TPU yellowing resistance treatment. They effectively reduce the damage to TPU molecules by absorbing ultraviolet energy and converting it into harmless forms. Common UV absorbers include benzotriazoles, benzophenones and salicylate compounds.

Category Features Representative Compound
Benzotriazoles Efficient absorption of medium and short wave ultraviolet rays, good stability, and difficult to migrate Tinuvin P, Chimassorb 81
Benzophenone Wide absorption range, low cost, but easy to migrate Uvinul M40, Tinuvin 326
Salicylate It has a good absorption effect on long-wave ultraviolet rays and is often used in transparent TPU products Parsol HS

Benzotriazoles

Benzotriazole compounds are highly favored for their high efficiency and stability. They can continuously absorb ultraviolet rays for a long time and are not easy to migrate out of TPU substrates. They are suitable for TPU products that are used outdoors for a long time.

Benzophenone

Benzophenone ultraviolet absorbers are relatively cheap and are suitable for application scenarios with limited budgets. However, due to its strong mobility, it may lead to precipitation on the surface of TPU products, so it should be used with caution.

Salicylates

Salicylate compounds have a good absorption effect on long-wave UV rays and are especially suitable for TPU products that require transparency, such as optical films and eyeglasses.


2. Antioxidants

Antioxidants effectively prevent the TPU from yellowing due to oxidation by capturing free radicals and interrupting the oxidation reaction chain. They are divided into two categories: primary antioxidants and secondary antioxidants.

Category Function Representative Compound
Main Antioxidant Catch free radicals and terminate the oxidation reaction chain Irganox 1076, Irganox 1010
Supplemental Antioxidants Decompose hydroperoxide and work in coordination with the main antioxidant Irgafos 168

Main Antioxidant

Main antioxidants such as Irganox 1076 and Irganox 1010 are able to quickly capture free radicals, preventing them from triggering further oxidation reactions. This type of compound usually has high thermal stability and long-term efficacy, and is suitable for TPU products under high temperature processing conditions.

Supplemental Antioxidants

Supply antioxidants such as Irgafos 168 focus on decomposing hydroperoxides, thereby reducing the burden on the main antioxidants. When used in combination, better antioxidant effects can be achieved.


3. Compound yellowing agent

Composite yellowing agent combines the advantages of UV absorbers and antioxidants, and can cope with the dual threats of UV and oxidation at the same time. This type of product is usually optimized for proportional design and is suitable for complex usage environments.

Category Features Representative Compound
Composite It has both ultraviolet absorption and antioxidant functions, and has excellent comprehensive performance Chimassorb 944, Tinuvin 123

Comprehensive Advantages

Composite yellowing agents such as Chimassorb 944 and Tinuvin 123 can provide comprehensive protection for TPUs, especially suitable for applications requiring long-term weather resistance, such as automotive interior parts and building membranes.


Comparison of current domestic and foreign research status and technology

The research and development of TPU yellowing agents has always been an important topic in the field of polymer materials worldwide. Scientists from various countries have invested a lot of resources in this field to continuously improve the performance of additives and expand their application scope. The following is a comparative analysis of the current domestic and foreign research status and technical level.

Progress in foreign research

European and American countries started early in the research of TPU yellowing agents and were in a leading position in the technology level. Well-known companies such as BASF in Switzerland, Clariant in Germany and Celanese in the United States have launched a variety of high-efficiency yellowing agent products. For example, BASF’s Tinuvin series UV absorbers and Irganox series antioxidants have dominated the international market.

The characteristics of foreign research include:

  • Highly innovative: Focus on developing new functional yellow-resistant agents, such as biodegradable environmentally friendly products.
  • Widely used: To meet the needs of different industries, customized solutions are launched, covering multiple fields from consumer electronics to aerospace.
  • Excellent performance: Through molecular structure optimization, the absorption efficiency and stability of the resistant yellowing agent are significantly improved.

Domestic research status

In recent years, China has made significant progress in research on TPU yelitising agents. Domestic scientific research institutions and enterprises have gradually mastered core technologies and production processes, and some products have reached the international advanced level. For example, Zhejiang Wankai New Materials Co., Ltd. and Jiangsu Ruihua Chemical Co., Ltd. have successively launched independently developed high-performance yellowing agents.

The advantages of domestic research are:

  • Cost Control: By optimizing formulas and processes, production costs are greatly reduced and market competitiveness is improved.
  • Local Service: Understand the local market demands and respond quickly to customer feedback.Provide more targeted products.
  • Green and Environmental Protection: Actively respond to national policies and vigorously develop low-toxic and harmless environmentally friendly yellowing agents.

Technical gap and development direction

Although domestic research has made great progress, there are still some shortcomings, which are mainly reflected in the following aspects:

  1. Insufficient research on basic theory: Compared with foreign countries, my country’s research on the design and mechanism of molecular structure of yellowing agents still needs to be strengthened.
  2. High-end product research and development lag: Some high-end yellowing agents still rely on imports, especially in special fields such as aerospace and medical devices.
  3. Improper standardization system: The lack of unified testing standards and evaluation methods affects the stability of product quality.

The future development direction should focus on the following aspects:

  • Strengthen basic research: In-depth exploration of the interaction mechanism between yellowing agents and TPU materials, laying a theoretical foundation for new product development.
  • Promote technological innovation: Use nanotechnology and smart material concepts to develop new yellowing agents with higher efficiency and versatility.
  • Improve the standard system: Establish scientific and reasonable testing methods and evaluation indicators to promote the comprehensive improvement of product quality.

Application methods and precautions for TPU yellowing agent

The correct use of TPU yellowing agent is the key to fully exerting its effectiveness. The following are some practical suggestions and precautions to help users achieve good results in actual operation.

Select to add proportions

The amount of yellowing agent added should be adjusted according to the specific use and use environment of the TPU material. Generally speaking, the recommended addition ratio is 0.1%~1.0% (mass fraction). For TPU products that are used outdoors for a long time, the added amount can be appropriately increased; for products that are used indoors for a short period of time, the amount can be reduced to reduce costs.

User scenarios Recommended addition ratio (mass fraction) Precautions
High requirements for outdoor weather resistance 0.5%~1.0% Ensure that the yellowing agent is evenly distributed
General use of indoors 0.1%~0.3% Avoid excessive addition and cause physical performance degradation
Special for medical devices 0.3%~0.5% Complied with relevant regulations

Sticks of stirring and mixing

The degree of dispersion of yellowing agent in TPU substrate directly affects its effect. Therefore, the following points should be paid attention to during the mixing process:

  • Full stir: Use high-speed stirring equipment to ensure that the yellowing agent is evenly distributed in the TPU particles.
  • Temperature Control: Avoid decomposition or failure of yellowing agents due to excessive high temperatures.
  • Time Management: Arrange the mixing time reasonably to ensure dispersion effect without wasting energy.

Storage and Transport Suggestions

When resistant yellowing agent is stored and transported, it should be protected from moisture, light and sealed to avoid affecting its performance. Especially ultraviolet absorbers, if exposed to strong light for a long time, may degrade themselves and lose their efficacy.


Summary and Outlook

TPU yellowing agents, as the “secret weapon” of high-performance TPU materials, play an irreplaceable role in resisting ultraviolet rays and delaying yellowing. By absorbing UV rays, inhibiting oxidation reactions and providing shielding effects, these additives provide TPU materials with full protection, allowing them to maintain excellent performance in various harsh environments.

With the advancement of technology and the continuous changes in market demand, the research and application of TPU yellowing agents will also usher in new development opportunities. In the future, we look forward to seeing more efficient, environmentally friendly and multifunctional new yellowing agents coming out, injecting stronger momentum into the widespread application of TPU materials. As a song sings: “Let every dream blossom.” I believe that with the efforts of scientists, the future of TPU materials will surely be even more brilliant!

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