Detailed explanation of the vulcanization process: from basic principles to modern applications

The vulcanization process is a key link in rubber processing. Through the vulcanization process, the rubber material changes from a linear molecular structure to a network structure, thereby obtaining the required physical and chemical properties. This article will provide a detailed analysis of the basic principles, process types, process parameters, equipment and applications of the vulcanization process.

1. Basic principles of vulcanization process

1. Definition of vulcanization

Vulcanization refers to the process in which rubber materials transform from a linear molecular structure into a three-dimensional network structure through a chemical cross-linking reaction under the action of heating and vulcanizing agents (such as sulfur). This process significantly improves the mechanical strength, wear resistance, heat resistance and chemical resistance of the rubber.

2. Chemical reaction of vulcanization

The vulcanization reaction mainly includes the cross-linking reaction between sulfur and rubber molecular chains. The specific reactions are as follows:

Rubber molecular chain + sulfur → cross-linked rubber

During the vulcanization process, sulfur molecules react with the double bonds on the rubber molecular chain to form sulfur bridge bonds, thereby forming a three-dimensional network structure.

3. Factors affecting vulcanization reaction

Types of vulcanizing agents: Different vulcanizing agents (such as sulfur, peroxide, organic vulcanizing agents) will affect the speed of the vulcanization reaction and the cross-linking density.

Vulcanization temperature: Increased temperature will accelerate the vulcanization reaction, but too high a temperature may cause vulcanization to return to its original state or material decomposition.

Vulcanization time: Too short a time may result in incomplete vulcanization, and too long a time may result in excessive vulcanization.

Fillers and additives: Fillers (such as carbon black) and additives (such as accelerators, antioxidants) will affect the rate of vulcanization reaction and the performance of the product.

2. Vulcanization process type

1. Traditional vulcanization process

Sulfur vulcanization: Uses sulfur as the primary vulcanizing agent, suitable for natural rubber and most synthetic rubbers.

Peroxide vulcanization: Use organic peroxide as the vulcanizing agent, suitable for rubber without double bonds (such as silicone rubber, fluorine rubber).

Vulcanization with organic vulcanizing agents: The use of organic vulcanizing agents (such as thiurams and disulfides) is suitable for some special rubbers.

2. New vulcanization process

Electron beam vulcanization: The use of high-energy electron beams to initiate vulcanization reactions, suitable for high-performance rubber products.

Microwave vulcanization: Using microwave heating, the vulcanization reaction is completed in a short time and improves production efficiency.

Supercritical fluid vulcanization: vulcanization in a supercritical carbon dioxide or nitrogen environment, suitable for environmentally friendly rubber products.

3. Vulcanization process parameters

1. Vulcanization temperature

Vulcanization temperature is one of the key parameters in the vulcanization process. Generally, the higher the vulcanization temperature, the faster the vulcanization reaction rate. However, too high a vulcanization temperature may lead to vulcanization reversion and material decomposition. The optimal vulcanization temperature range of different rubber materials is different, and the appropriate vulcanization temperature needs to be selected according to the specific material.

2. Vulcanization time

Vulcanization time refers to the time the rubber material remains at the vulcanization temperature. The length of vulcanization time directly affects the degree of vulcanization. A vulcanization time that is too short may result in incomplete vulcanization, and a vulcanization time that is too long may result in excessive vulcanization. Usually, the vulcanization time needs to be determined through experiments to achieve the best vulcanization effect.

3. Vulcanization pressure

The vulcanization pressure helps the flow and filling of the rubber material, ensuring the uniformity and compactness of the rubber material during the vulcanization process. Proper vulcanization pressure can reduce the generation of bubbles and defects and improve the quality of vulcanized products.

4. Dosage of vulcanizing agent

The amount of vulcanizing agent directly affects the rate of vulcanization reaction and cross-linking density. Using too little vulcanizing agent may result in incomplete vulcanization, while using too much vulcanizing agent may result in excessive vulcanization. Typically, the amount of vulcanizing agent needs to be optimized based on the specific rubber material and type of vulcanizing agent.

4. Vulcanization equipment

1. Flat plate vulcanizing machine

Plate vulcanizing machine is one of the most commonly used vulcanizing equipment and is suitable for producing various rubber products, such as rubber plates, rubber tubes and rubber mats. The flat plate vulcanizer vulcanizes the rubber material in the mold by heating the flat plate and applying pressure.

2. Vulcanization tank

The vulcanization tank is suitable for continuous vulcanization process and is suitable for the production of rubber belts, rubber tubes and rubber seals, etc. The vulcanization tank vulcanizes the rubber material in a closed environment by heating and pressurizing it.

3. Calendering vulcanizing machine

Calendering vulcanizing machines are suitable for producing wide-width rubber products, such as rubber sheets and rubber plates. The calendering and vulcanizing machine vulcanizes the rubber material in a continuous process through calendering and heating.

4. Microwave vulcanization equipment

Microwave vulcanization equipment uses microwave heating to complete the vulcanization reaction in a short time, and is suitable for the production of high-performance rubber products. Microwave vulcanization equipment has the advantages of high efficiency, energy saving and environmental protection.

5. Application of vulcanization process

1. Tire manufacturing

The vulcanization process plays a vital role in tire manufacturing. Through the vulcanization process, the tire rubber material obtains the required mechanical strength, wear resistance and heat resistance, ensuring that the tire has good performance under various road conditions.

2. Rubber seals

The vulcanization process is used to produce various rubber seals, such as O-rings, U-rings, and Y-rings. Through the vulcanization process, the seals obtain the required sealing performance and chemical corrosion resistance, ensuring the reliability and safety of the sealing system.

3. Rubber tubes and hoses

The vulcanization process is used to produce various rubber pipes and hoses, such as hydraulic pipes, pneumatic pipes, and food-grade hoses. Through the vulcanization process, rubber pipes and hoses acquire the required pressure resistance, abrasion resistance and chemical resistance, ensuring their reliability in a variety of applications.

4. Rubber pads and rubber plates

The vulcanization process is used to produce various rubber pads and rubber sheets, such as anti-slip pads, shock-absorbing pads and sound-insulating pads, etc. Through the vulcanization process, rubber pads and rubber sheets acquire the required mechanical strength, wear resistance and heat resistance, ensuring their performance in a variety of applications.

6. Future development trends of vulcanization process

1. Green and environmentally friendly vulcanization

With the improvement of environmental awareness, green and environmentally friendly vulcanization technology will become the future development trend. Research and development of vulcanizing agents and vulcanizing processes with low VOC emissions, low energy consumption and recyclability will become an important research direction.

2. Intelligent vulcanization

Intelligent vulcanization equipment and processes will improve production efficiency and product quality. By introducing the Internet of Things, big data and artificial intelligence technology, real-time monitoring and optimization of the vulcanization process can be achieved, and the accuracy and reliability of the vulcanization process can be improved.

3. High performance vulcanization

With the continuous development of new materials and new technologies, high-performance vulcanization processes will meet more application needs. Through research and development of new vulcanizing agents, vulcanizing processes and vulcanizing equipment, we improve the performance and functions of vulcanized products and expand their application areas.

7. Summary

The vulcanization process is a key link in rubber processing. Through the vulcanization process, rubber materials obtain the required physical and chemical properties. This article provides a detailed analysis of the basic principles, process types, process parameters, equipment and applications of the vulcanization process. With the development of technology and the diversification of needs, the vulcanization process will continue to innovate in the direction of green, environmental protection, intelligence and high performance, providing more reliable technical support for the development of the rubber industry.

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