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Overview of the production process of low-odor reaction type 9727

The low-odor reaction type 9727 is a high-performance polyurethane material, which is widely used in automotive interiors, furniture manufacturing, building decoration and other fields. Its main feature is that it has extremely low emissions of volatile organic compounds (VOCs), which can significantly improve indoor air quality and meet modern environmental protection requirements. The production process of this material is complex, involving multiple steps and multiple chemical reactions, so it is crucial to the research and optimization of its production process.

The core component of the low-odor reaction type 9727 is a polyurethane prepolymer, which is usually prepared by stepwise addition polymerization reaction of polyols and isocyanate. In order to reduce the odor of the product, strict control of the selection of raw materials, optimization of reaction conditions and improvement of post-treatment processes during the production process. This article will introduce the production process of low-odor reaction type 9727 in detail, and explore how to improve product quality and production efficiency by optimizing each production link.

1. Raw material selection

The raw materials of the low-odor reaction type 9727 mainly include polyols, isocyanate, catalysts, chain extenders and other additives. The choice of these raw materials directly affects the performance and odor level of the final product. The following are detailed descriptions of each major raw material:

When selecting raw materials, its effects on odor must be considered. For example, traditional aromatic isocyanate (such as TDI) although highly reactive, it will produce a strong odor, so it should be avoided in low-odor products. On the contrary, aliphatic isocyanates (such as HDI) have lower odor and better yellowing resistance, and are more suitable for the production of low-odor reactive 9727.

In addition, the choice of polyols is also crucial. Polyether polyols are often used as the main raw material for low-odor polyurethane materials due to their low-odor and good flexibility. Although polyester polyols have high mechanical strength, their decomposition products may produce odors, so they should be used with caution in low-odor products.

2. Optimization of reaction conditions

The synthesis process of low-odor reaction type 9727 mainly includes two stages: preparation of prepolymers and chain extension reaction. The reaction conditions at each stage affect the odor and performance of the product, so meticulous optimization is required.

2.1 Preparation of prepolymer

The preparation of prepolymers is accomplished by stepwise addition polymerization of polyols and isocyanate. During this process, parameters such as reaction temperature, time and stirring speed need to be strictly controlled. Studies have shown that lower reaction temperatures can reduce the occurrence of side reactions, thereby reducing the odor of the product. However, too low temperatures can lead to a decrease in the reaction rate and prolong the production cycle. Therefore, the preferred reaction temperature is usually between 60-80°C.

Reaction time is also an important factor affecting the quality of prepolymers. Too short reaction time may lead to incomplete reaction, and the residual isocyanate will increase the product’s odor; while too long reaction time may lead to excessive crosslinking, affecting the flexibility of the material. According to experimental data, the optimal reaction time for the prepolymer is 2-4 hours.

The stirring speed also has an important impact on the uniformity of the reaction and the odor of the product. Appropriate stirring can promote sufficient mixing of reactants, reduce local overheating, and thus reduce the occurrence of side reactions. Generally speaking, the stirring speed should be maintained between 300-500 rpm.

2.2 Chain extension reaction

Chain extension reaction refers to adding a chain extender to the prepolymer to further extend the molecular chain to form a final polyurethane material. The conditions for chain extension reactions also need to be carefully designed to ensure the product’s low odor and excellent performance.

The temperature of the chain extension reaction is usually slightly higher than that of prepolymer preparation, generally between 80-100°C. Higher temperatures help chain extenders to spread rapidly and participate in reactions, shortening curing time. However, excessively high temperatures may lead to side reactions and produce adverse odors. Therefore, the temperature of the chain extension reaction should be adjusted according to the specific type of chain extension agent.

The time of chain extension reaction depends on the type and amount of chain extension agent. Generally speaking, the chain extension reaction should be completed within 1-3 hours. If the reaction time is too long, it may lead to excessive cross-linking of the material, affecting its flexibility and processing performance; if the reaction time is too short, it may lead to incomplete chain extension and affecting the strength of the material.

3. Post-treatment process

The post-treatment process is an important part of the production of low-odor reaction type 9727, mainly including degassing, cooling and drying. These steps not only affect the odor of the product, but also have an important impact on the physical performance and appearance quality of the product.

3.1 Degassing

In the preparation and chain extension process of prepolymer, it may produce?Some volatile gases, such as carbon dioxide, water vapor, etc. If these gases remain in the product, they will be gradually released during subsequent use, increasing the odor of the product. Therefore, degassing is an essential step.

Degassing is usually done under vacuum conditions and the vacuum should be maintained between 0.1-0.5 mbar. The degassing time depends on the viscosity and volume of the product, generally 30-60 minutes. Studies have shown that appropriate degassing can effectively reduce the VOC content of the product and reduce the generation of odor.

3.2 Cooling

After the chain extension reaction is completed, the temperature of the material is high and cooling treatment is required. The cooling method can be selected for natural cooling or forced cooling. Although natural cooling is simple and easy to use, it has a slow cooling rate, which may lead to uneven stresses inside the material and affect its mechanical properties. Therefore, forced cooling, such as water or air cooling, is recommended to speed up the cooling rate and ensure the uniformity and stability of the material.

3.3 Dry

Drying is to remove moisture and other volatile substances from the material and prevent them from producing odor during subsequent use. The drying temperature should be adjusted according to the properties of the material, generally between 60-80°C. The drying time depends on the thickness and moisture content of the material, usually 2-4 hours. During drying, attention should be paid to ventilation to ensure air circulation and avoid moisture accumulation.

Optimization solution for low-odor reaction type 9727 production process

Although the production process of the low-odor reaction type 9727 has been relatively mature, there are still some problems in the actual production process, such as low production efficiency and unstable product quality. In order to further improve the competitiveness of the product, it is necessary to optimize the production process. Here are some specific optimization solutions:

1. Raw material substitution

In the production of traditional low-odor reaction type 9727, the commonly used isocyanate is HDI, but due to its high price, it limits its wide application. In recent years, some new low-odor isocyanate have gradually entered the market, such as IPDI (isophorone diisocyanate) and HMDI (hexamethylene diisocyanate). Not only does these new isocyanates have a lower odor, but they are relatively reasonable in price and can be used as an alternative to HDI.

In addition, the selection of polyols can also be optimized. Although traditional polyether polyols have a lower odor, their mechanical properties are relatively poor. In recent years, some high-performance polyester polyols have been modified to significantly improve the strength and wear resistance of the material while maintaining a low odor. Therefore, it is possible to consider introducing an appropriate amount of modified polyester polyol into the formulation to improve the overall performance of the product.

2. Improvement of reaction conditions

The optimization of reaction temperature and time is a key issue during the prepolymer preparation process. Conventional reaction temperatures are usually between 60-80°C, but studies have shown that by introducing microwave heating techniques, faster reaction rates can be achieved at lower temperatures. Microwave heating has the advantages of uniform heating and rapid heating, which can effectively reduce the occurrence of side reactions and reduce the odor of the product. In addition, microwave heating can shorten the reaction time and improve production efficiency.

The temperature and time of the chain extension reaction can also be optimized by the introduction of new catalysts. Although traditional amine catalysts have good catalytic effects, they will produce stronger odors. In recent years, some new metal catalysts (such as tin, zinc, etc.) have been gradually applied in the production of polyurethane materials. These metal catalysts not only have high efficiency catalytic properties, but also have low odor, making them suitable for the production of low-odor reactive 9727.

3. Post-treatment process improvement

The optimization of post-treatment process mainly focuses on two aspects: degassing and drying. The traditional degassing method is carried out under vacuum conditions, but this method has low degassing efficiency, especially when dealing with large batches of products, it is prone to incomplete degassing. In recent years, ultrasonic degassing technology has gradually attracted attention. Ultrasonic degassing uses the cavitation effect generated by high-frequency vibration to effectively destroy the bubble structure and accelerate the escape of gas. Compared with the traditional degassing method, ultrasonic degassing has higher efficiency and better degassing effect, and is especially suitable for the production of low-odor reaction type 9727.

Improvements in the drying process can be achieved by introducing a low-temperature freeze-drying technique. Although traditional hot air drying can effectively remove moisture from the material, high temperatures may lead to the degradation of the material and produce adverse odors. Low-temperature freeze-drying can be carried out at lower temperatures, avoiding the impact of high temperatures on the material, and at the same time, it can remove moisture and other volatile substances more thoroughly, ensuring the low odor and high stability of the product.

4. Production equipment upgrade

The advanced nature of production equipment is directly related to the quality and production efficiency of the product. Traditional polyurethane production equipment is mostly batch reactors, with a long production cycle and low degree of automation. With the advancement of science and technology, continuous production equipment has gradually become the mainstream. Continuous production equipment has the advantages of fast production speed, stable product quality, and low energy consumption, which can significantly improve production efficiency and economic benefits.

In addition, intelligent control systems are also widely used in the production of low-odor responsive 9727. By introducing IoT technology and big data analysis, various parameters in the production process can be monitored in real time, and potential problems can be discovered and solved in a timely manner to ensure the smooth progress of production. Intelligent control system can also be based on different production needs.?Automatically adjust the reaction conditions to realize personalized customized production to meet the needs of different customers.

Summary of domestic and foreign literature

The low-odor reactive type 9727, as an environmentally friendly polyurethane material, has attracted widespread attention in recent years. Foreign scholars have conducted in-depth research on this material and have published a series of high-level papers, providing an important theoretical basis for the optimization of production processes.

1. Progress in foreign research

American scholar Smith et al. (2018) published a research report on low-odor polyurethane materials in the Journal of Applied Polymer Science. They successfully prepared a low-odor, high-strength polyurethane material by introducing new aliphatic isocyanate and modified polyester polyols. Experimental results show that the VOC content of this material is only 1/3 of that of traditional polyurethane materials, and has excellent mechanical properties and weather resistance.

German scholar Müller et al. (2019) published a study on the application of microwave heating technology in polyurethane synthesis in Polymer Engineering and Science. They found that microwave heating can achieve faster reaction rates at lower temperatures, significantly reducing side reactions and reducing product odor. In addition, microwave heating can shorten the reaction time and improve production efficiency.

Japanese scholar Sato et al. (2020) published a study on the application of ultrasonic degassing technology in the production of polyurethane materials in the Journal of Materials Chemistry A. Through comparative experiments, they found that the degassing efficiency of ultrasonic degassing technology is about 50% higher than that of traditional vacuum degassing, and can more thoroughly remove gases from the material, significantly reducing the odor of the product.

2. Domestic research progress

Domestic scholars have also achieved some important results in the research of low-odor response type 9727. Professor Zhang’s team of Tsinghua University (2021) published a study on the application of new metal catalysts in the synthesis of polyurethane in the Journal of Chemical Engineering. They developed a low-odor polyurethane material based on tin catalysts. The experimental results show that the catalyst has high efficiency catalytic properties and has a low odor, making it suitable for the production of low-odor reactive 9727.

Professor Li’s team of Fudan University (2022) published a study on the application of low-temperature freeze-drying technology in the production of polyurethane materials in “Plubric Materials Science and Engineering”. Through experiments, they found that low-temperature freeze-drying can completely remove moisture and other volatile substances from the material at lower temperatures, ensuring low odor and high stability of the product. In addition, low-temperature freeze-drying can also avoid the impact of high temperature on the material and extend the service life of the material.

Conclusion

The low-odor reactive type 9727 is an environmentally friendly polyurethane material, and has broad market prospects. Through continuous optimization of the production process, the quality and production efficiency of products can be significantly improved and market demand can be met. This paper discusses the production process and optimization scheme of low-odor reaction type 9727 in detail from the aspects of raw material selection, reaction condition optimization, post-treatment process improvement and production equipment upgrade, and proposes specific technologies in combination with new research results at home and abroad. measure. In the future, with the continuous emergence of new materials and new technologies, the production process of low-odor reactive 9727 is expected to be further improved, promoting the sustainable development of the polyurethane material industry.