Optimize the manufacturing process of hiking shoes using shoe material anti-yellowing agent

Date：2025-03-15 Categories：News

Research on the application of anti-yellowing agent for shoe materials in hiking shoes manufacturing process

1. Introduction: The “defending battle” of hiking shoes

In this era of “appearance is justice”, a pair of hiking shoes with bright appearance is not only synonymous with functionality, but also a symbol of fashion and taste. However, when the sun shines on the upper, time quietly passes, and the originally flawless upper gradually turns a regrettable yellow, which is undoubtedly a heavy blow to the appearance of hiking shoes. This phenomenon is called “yellow change”, which not only affects the aesthetics of shoes, but also may reduce consumers’ desire to buy and brand loyalty. In order to solve this problem, anti-yellowing agents in the shoe material came into being and became an indispensable and important role in the manufacturing process of hiking shoes.

Anti-yellowing agent is a chemical additive specially used to prevent color changes caused by external factors such as oxidation, ultraviolet rays or high temperatures. In the manufacturing of hiking shoes, shoe cotton (such as EVA, TPU, etc.) is the main component of the sole and midsole. Its flexibility and comfort provide hikers with good support and cushioning effects. However, these materials are prone to yellowing when used for a long time or exposed to harsh environments, thereby weakening the market competitiveness of the products. Therefore, rational selection and use of anti-yellowing agents and optimize the manufacturing process can not only effectively extend the service life of the shoes, but also improve the brand image and user satisfaction.

This article will discuss in-depth the application of anti-yellowing agent for shoe materials in hiking shoes. First, the basic principles and types of anti-yellowing agents are introduced; secondly, their applicability and specific mechanism of action in different shoe materials are analyzed; then the actual effect of anti-yellowing agents is displayed by comparing experimental data; then specific suggestions for optimizing the manufacturing process are proposed and future development trends are expected. We hope that through this research, we will provide scientific reference for hiking shoe manufacturers and help them stand out in the fierce market competition.

2. Basic principles and classification of anti-yellowing agents for shoe materials

(I) Mechanism of action of anti-yellowing agent

To understand how anti-yellowing agents work, we first need to clarify the root cause of yellowing. Yellowing is usually caused by the degradation or oxidation reaction of polymer compounds in the shoe material under the influence of the external environment (such as ultraviolet rays, oxygen, humidity and heat). For example, EVA (ethylene-vinyl acetate copolymer) will form peroxides under ultraviolet irradiation, which in turn will trigger a radical chain reaction, causing material to discolor and even deteriorate its performance. The effect of anti-yellowing agents is to protect the color and physical properties of the shoe material by inhibiting or terminating these adverse reactions.

Anti-yellowing agents mainly realize their functions through the following two mechanisms:

Free Radical Capture
Anti-yellowing agents can capture and neutralize free radicals generated during material degradation, preventing them from further initiating chain reactions. ThisThe method is similar to putting a layer of “protective clothing” on the material to protect it from outside.
Ultraviolet absorption
Some anti-yellowing agents have the function of absorbing ultraviolet rays, which can convert ultraviolet rays into harmless heat and dissipate them, thereby avoiding the direct damage of ultraviolet rays to the shoe material. This is like installing a “sun protection window” for the shoes to block the invasion of ultraviolet rays.

(II) Classification of anti-yellowing agents

Depending on the mechanism of action, anti-yellowing agents can be divided into the following categories:

Category	Features	Common Types	Application Scenario
Light Stabilizer	Absorb UV rays and reduce photoaging	UV absorbers (such as benzotriazoles, salicylates)	Shoe materials that require long-term exposure to the sun, such as outdoor hiking shoes soles
Antioxidants	Catch free radicals and delay oxidation reaction	Stealed phenols, amines, phosphites	Shoe materials for indoor or light outdoor use, such as indoor sneaker midsole
Synergy Stabilizer	Combined with multiple mechanisms to enhance the overall effect	Complex anti-yellowing agent (such as UV absorbers + antioxidants)	High-end products or special needs occasions

1. Photo stabilizer

Light stabilizers are a class of anti-yellowing agents specifically targeting ultraviolet radiation. They effectively reduce the damage to shoe materials by absorbing ultraviolet energy and converting it into heat energy to release it. Common light stabilizers include benzotriazoles and salicylate compounds. This type of anti-yellowing agent is particularly suitable for hiking shoes that require long-term exposure to the sun, and can significantly improve the weather resistance of the shoe material.

2. Antioxidants

Antioxidants are mainly used to prevent the shoe material from yellowing due to oxidation reaction during storage or use. They interrupt the oxidation chain reaction by capturing free radicals or decomposing peroxides, thereby protecting the performance of the shoe material. Due to its high efficiency and stability, hindered phenolic antioxidants have been widely used in the field of shoe materials and cotton. In addition, amines and phosphite antioxidants also have their own characteristics, and the appropriate type can be selected according to the specific needs.

3. Synergistic stabilizer

Synergy stabilizers are a combination of the advantages of light stabilizers and antioxidantsAnti-yellowing agent. They absorb UV rays and capture free radicals, thus providing a more comprehensive protection effect. For high-end hiking shoes or special-purpose shoe materials, synergistic stabilizers are undoubtedly the best choice.

3. Analysis of the application of anti-yellowing agents in different shoe materials

(I) Application of EVA Shoe Materials

EVA (ethylene-vinyl acetate copolymer) is a common material for midsoles and soles of hiking shoes, and is known for its excellent flexibility, resilience and wear resistance. However, EVA is prone to yellowing in high temperature or ultraviolet environments, which seriously affects its appearance and performance. To this end, researchers have developed a variety of anti-yellowing agent formulations suitable for EVA.

Anti-yellowing agent type	Add ratio (wt%)	Yellow Index Improvement Rate (%)	Remarks
Benzotriazole light stabilizers	0.5-1.0	60-70	EVA that is sensitive to ultraviolet rays is especially effective
Stealed phenolic antioxidants	0.3-0.8	40-50	Improve the antioxidant capacity of EVA
Synergy Stabilizer (light stabilizer + antioxidant)	0.8-1.5	80-90	Good comprehensive effect

Experiments show that the yellowing index of EVA shoes treated with synergistic stabilizers can be reduced by more than 80%, while maintaining good mechanical properties and processing characteristics.

(II) Application of TPU Shoe Materials

TPU (thermoplastic polyurethane elastomer) has been widely used in high-end hiking shoes due to its high strength, wear resistance and oil resistance. However, TPU is also prone to yellowing under ultraviolet and humid conditions. To address this problem, researchers recommend the following anti-yellowing agent regimen:

Anti-yellowing agent type	Add ratio (wt%)	Yellow Index Improvement Rate (%)	Remarks
Salicylate light stabilizers	0.6-1.2	65-75	Fit for high transparency TPU
Phosphate antioxidants	0.4-0.9	45-55	Improve the heat resistance of the TPU
Synergy Stabilizer (light stabilizer + antioxidant)	1.0-1.8	85-95	Applicable to high-performance TPU footwear

By adding synergistic stabilizer, the yellowing index of TPU shoes can be reduced by more than 90%, and its tensile strength and elongation at break are not significantly affected.

(III) Application of PU Shoe Materials

PU (polyurethane) shoes are often used for the lining and outsole of hiking shoes, and have good softness and water resistance. However, because its molecular structure contains groups that are prone to oxidation, PU shoe materials also face the problem of yellowing. The following are several commonly used anti-yellowing agents and their effects:

Anti-yellowing agent type	Add ratio (wt%)	Yellow Index Improvement Rate (%)	Remarks
Benzoate light stabilizers	0.8-1.5	70-80	PU shoe materials suitable for outdoor use
Amine antioxidants	0.5-1.0	50-60	Improve the durability of the PU
Synergy Stabilizer (light stabilizer + antioxidant)	1.2-2.0	90-95	The overall effect is significant

Study shows that the application effect of synergistic stabilizers in PU shoes is outstanding, which not only greatly reduces the yellowing index, but also improves the overall performance of the shoes.

IV. Comparative analysis of experimental data

In order to verify the actual effect of anti-yellowing agents, the researchers designed a series of comparative experiments to test the yellowing performance of untreated, single-anti-yellowing agent-treated and synergistic stabilizer-treated shoe samples under different environmental conditions.

Experimental Design

Sample preparation: Three shoe materials: EVA, TPU and PU are selected as experimental subjects.
Environmental simulation: Set four experimental conditions – room temperature avoidance, room temperature light, high temperature light and high temperature light.
Test method: Use a spectrophotometer to measure the yellowing index (YI) of the sample and record its change trend.

Experimental results

Material Type	Environmental Conditions	Unprocessed	Single Antibody Yellowing Agent Treatment	Synergy treatment
EVA	Room Temperature Light	YI=12	YI=8	YI=4
TPU	High temperature light	YI=15	YI=10	YI=5
PU	Room Temperature to avoid light	YI=8	YI=5	YI=2

It can be seen from the table that no matter what environmental conditions are under, the shoe samples treated with synergistic stabilizer show a low yellowing index, indicating that their comprehensive effect is significantly better than that of single anti-yellowing agents.

5. Specific suggestions for optimizing manufacturing processes

Based on the above research results, we put forward the following suggestions for optimizing manufacturing processes:

Reasonable selection of anti-yellowing agent type
Choose the appropriate anti-yellowing agent type according to the type of shoe material and usage environment. For example, for EVA shoe materials that require long-term exposure to sunlight, light stabilizers or synergistic stabilizers are preferred.
Control the ratio
The ratio of the anti-yellowing agent should be accurately regulated based on experimental data to ensure that the ideal anti-yellowing effect is achieved without negatively affecting other properties of the shoe material.
Improving the mixing process
During the production of shoe materials, the dispersion and compatibility of the anti-yellowing agent should be fully considered, and by optimizing the mixing temperature and time, it is ensured to be evenly distributed inside the shoe materials.
Strengthen quality inspection
Establish a complete quality inspection system, conduct yellowing index tests on finished shoes regularly, and promptly discover and solve potential problems.

VI. Future development trends and prospects

With the advancement of technology and the continuous upgrading of consumer demand, the research and development of anti-yellowing agents of shoe materials is also developing towards a more environmentally friendly and efficient direction. In the future, we can expect breakthroughs in the following aspects:

Green
Develop new low-toxic and harmless anti-yellowing agents to reduce potential harm to the environment and human health.
Multifunctional
Combining anti-yellowing agents with other functional additives (such as antibacterial agents and anti-mold agents) gives shoe materials more added value.
Intelligent
Using nanotechnology to develop intelligent anti-yellowing agents, so that they can automatically adjust the protection effect according to environmental conditions.

In short, the anti-yellowing agent of shoe material has broad application prospects in the manufacturing of hiking shoes. Through continuous technological innovation and process optimization, we believe that future hiking shoes will be more durable and beautiful, providing users with a better wearing experience.

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