Technical discussion on the rapid curing process of NIAX polyurethane catalyst

Introduction

Polyurethane (PU) is a high-performance material widely used in industrial and consumer goods fields, and is highly favored for its excellent mechanical properties, chemical resistance and wear resistance. However, the curing process of polyurethane has always been one of the key factors that restrict its application efficiency. Traditional polyurethanes have a long curing time, resulting in a prolonged production cycle and increasing manufacturing costs. Therefore, how to achieve faster polyurethane curing has become a research hotspot in the industry.

In recent years, with the advancement of catalyst technology, especially the application of NIAX series catalysts, the curing speed of polyurethane has been significantly improved. NIAX catalyst is a high-efficiency polyurethane catalyst developed by Dow Chemical Company in the United States. It is widely used in foams, coatings, adhesives and other fields. These catalysts can not only accelerate the reaction rate of polyurethane, but also effectively control side reactions during the reaction process, ensuring the quality stability and superior performance of the final product.

This article will conduct in-depth discussions on NIAX polyurethane catalysts, analyze their mechanisms, product parameters, and application fields in achieving faster curing, and combine new research results at home and abroad to explore its future development trends. The article will be divided into the following parts: first, introduce the basic principles of polyurethane and its curing process; second, elaborate on the technical characteristics and advantages of NIAX catalyst; then analyze the influence of NIAX catalyst on the curing rate of polyurethane through experimental data and literature citations; Summarize the full text and look forward to future research directions.

The basic principles of polyurethane and its curing process

Polyurethane (PU) is a polymer material produced by stepwise addition polymerization reaction of isocyanate and polyol. Its basic reaction formula can be expressed as:

[ R-N=C=O + HO-R’ rightarrow R-NH-CO-O-R’ ]

Where R and R’ represent organic groups, N=C=O is an isocyanate group, and HO- is a hydroxyl group. This reaction creates a aminomethyl ester bond (-NH-CO-O-), which is the main structural unit of the polyurethane molecular chain. Depending on the reactants, polyurethane can form different forms, such as soft foam, rigid foam, elastomer, coatings and adhesives.

Currecting process

The curing process of polyurethane refers to the process of converting from a liquid or semi-solid prepolymer to a solid material with specific physical and mechanical properties. This process usually includes the following steps:

  1. Mixing Stage: Isocyanate and polyol are mixed in a certain proportion to form a uniform reaction system. At this time, the two reactants have not undergone significant chemical reactions, but the conditions for the reaction have been met.

  2. Induction period: In the early stage after mixing, due to the high concentration of reactants and the slow reaction rate, the system is in a relatively stable induction period. The length of this stage depends on the type of reactants, temperature, and the presence or absence of the catalyst.

  3. Gelation stage: As the reaction progresses, isocyanate gradually reacts with the polyol to form a aminomethyl ester bond. At this time, the molecular chains begin to cross-link, the viscosity of the system increases rapidly, forming a gel-like substance. This stage is a key link in the curing process, which determines the shape and dimensional stability of the final product.

  4. Hardening stage: After gelation, the reaction continues, more aminomethyl ester bonds are formed, the molecular chains are further cross-linked, the system gradually hardens, and finally forms with fixed shape and mechanical properties. solid material. The reaction rate at this stage is slow, but it has a great impact on the performance of the final product.

  5. Post-treatment phase: In order to improve the performance of the product, the cured polyurethane material usually needs to be post-treated, such as heating, cooling, mold release, etc. These treatment steps help eliminate internal stress, improve surface quality and enhance mechanical properties.

Factors affecting curing speed

The curing rate of polyurethane is affected by a variety of factors, mainly including the following points:

  • Types and proportions of reactants: Different types of isocyanate and polyols have different reactivity activities, and choosing a suitable reactant combination can significantly affect the curing rate. For example, aromatic isocyanate has higher reactivity than aliphatic isocyanate, while high-functional polyols can speed up the reaction rate.

  • Temperature: Temperature is one of the important factors affecting the curing rate of polyurethane. Generally speaking, the higher the temperature, the faster the reaction rate and the shorter the curing time. However, excessively high temperatures may lead to side reactions that affect the performance of the final product.

  • Catalytic Selection: Catalysts can accelerate the curing process of polyurethane by reducing the reaction activation energy. Different catalysts have different effects on the reaction rate. Choosing the right catalyst can effectively shorten the curing time while ensuring the quality of the product.

  • Humidity: The moisture in the air will react with isocyanate to produce carbon dioxide and urea compounds, which will not only affect the curing rate of polyurethane, but may also lead to the generation of bubbles and affect the product’s Appearance and performance.

  • Addants: Certain additives (such as foaming agents, plasticizers, and stable� etc.) can adjust the curing process of polyurethane and change its physical and chemical properties. Rational use of additives can optimize the curing process and improve the overall performance of the product.

To sum up, the curing process of polyurethane is a complex chemical reaction system, which is affected by a combination of multiple factors. In order to achieve faster curing, the above factors must be considered comprehensively and appropriate reaction conditions and catalysts must be selected. Next, we will focus on the application of NIAX catalyst in the process of polyurethane curing and its technical characteristics.

Technical features and advantages of NIAX catalyst

NIAX catalyst is a high-efficiency polyurethane catalyst developed by Dow Chemical Company, which is widely used in foams, coatings, adhesives and other fields. What is unique about this type of catalyst is that it can significantly accelerate the curing process of polyurethane without sacrificing product quality. The following are the main technical features and advantages of NIAX catalysts:

1. High-efficiency catalytic performance

The core component of the NIAX catalyst is a series of organometallic compounds, especially complexes based on metals such as tin, bismuth, zinc, etc. These metal ions have strong nucleophilicity and can effectively reduce the reaction activation energy between isocyanate and polyol, thereby accelerating the curing process of polyurethane. Specifically, NIAX catalysts improve catalytic efficiency through the following mechanisms:

  • Reduce reaction activation energy: Metal ions form complexes with isocyanate groups, reducing the energy required for the reaction and making the reaction more likely to occur. Research shows that NIAX catalysts can shorten the curing time of polyurethane to a fraction of the traditional catalyst, or even shorter.

  • Promote hydrogen bond fracture: During the polyurethane curing process, the presence of hydrogen bonds will hinder contact between reactants and reduce the reaction rate. NIAX catalysts can destroy hydrogen bonds, allowing reactants to contact more fully, thereby speeding up the reaction process.

  • Inhibition of side reactions: In addition to accelerating the main reaction, NIAX catalyst can also effectively inhibit the occurrence of side reactions. For example, it can reduce the side reaction of isocyanate with water by combining with water molecules, avoiding the production of excessive carbon dioxide and urea compounds, thereby improving the purity and performance of the product.

2. Wide application scope

NIAX catalysts are suitable for a variety of polyurethane systems, including soft foams, rigid foams, elastomers, coatings and adhesives. Depending on the needs of different applications, Dow Chemical has developed multiple series of NIAX catalysts, such as NIAX T series, NIAX B series, NIAX Z series, etc. Each series has its own unique performance characteristics to meet different application scenarios Require.

  • NIAX T Series: Mainly contains tin metal ions, suitable for the production of soft foams and elastomers. The T-series catalysts have high catalytic activity and can significantly shorten the foam foaming time and curing time while maintaining good foam structure and mechanical properties.

  • NIAX Series B: Mainly contains bismuth metal ions, suitable for the production of rigid foams and coatings. The B series catalyst has low toxicity, meets environmental protection requirements, and can effectively catalyze reactions at low temperatures, and is suitable for temperature-sensitive applications.

  • NIAX Z Series: Mainly contains zinc metal ions, suitable for the production of adhesives and sealants. Z series catalysts have good storage stability and hydrolysis resistance, can maintain efficient catalytic activity in humid environments, and are suitable for outdoor construction and long-term storage products.

3. Environmental protection and safety

With the increasing global environmental awareness, the sustainable development of the polyurethane industry has become an important issue. The NIAX catalyst is designed with environmental protection and safety factors in full consideration. It uses low-toxic, halogen-free organometallic compounds as active ingredients to reduce the potential harm to the environment and human health. In addition, NIAX catalysts also have good storage stability and hydrolysis resistance, and can maintain high activity during transportation and storage, avoiding waste caused by deterioration.

  • Low toxicity: Compared with traditional heavy metal catalysts such as mercury and lead, metal ions such as tin, bismuth, zinc in NIAX catalysts have lower toxicity and meet international environmental standards. Especially in areas such as food packaging and medical devices that require high safety requirements, NIAX catalysts are more widely used.

  • Halogen-free: Halogen compounds will produce harmful gases when burned, causing pollution to the environment. NIAX catalysts do not contain halogen components, which avoids this problem and is in line with the concept of green chemistry.

  • Storage Stability: NIAX catalyst has good storage stability and can be stored for a long time at room temperature without losing its activity. This is especially important for industrial production, as it reduces production disruptions and economic losses due to catalyst failure.

4. Economic benefits

NIAX catalysts not only have obvious technical advantages, but also perform well in terms of economic benefits. Due to its efficient catalytic properties, the use of NIAX catalysts can significantly shorten the curing time of polyurethane, improve production efficiency, reduce energy consumption and manufacturing costs. In addition, the NIAX catalyst is used in a small amount.The unit cost is low, which can bring higher economic benefits to the enterprise without affecting product quality.

  • Shorten the production cycle: By accelerating the curing process of polyurethane, NIAX catalysts can help enterprises complete production tasks faster, reduce equipment occupancy time, and improve production line utilization.

  • Reduce energy consumption: Due to the shortening of curing time, the operating time of production equipment is also reduced, thereby reducing energy consumption. This can save a lot of electricity and thermal costs every year for large factories.

  • Reduce waste: The efficient catalytic performance makes the polyurethane reaction more complete, reduces the residue of unreacted raw materials, and reduces the amount of waste generated. This is of great significance to environmental protection and resource utilization.

To sum up, NIAX catalysts occupy an important position in the polyurethane industry due to their efficient catalytic performance, wide application range, environmental protection and safety characteristics and significant economic benefits. Next, we will further explore the specific impact of NIAX catalyst on the curing rate of polyurethane through experimental data and literature citations.

Experimental data and literature citations

In order to more comprehensively understand the impact of NIAX catalyst on the curing rate of polyurethane, this section will conduct detailed analysis and discussion based on experimental data and relevant domestic and foreign literature. The experimental part mainly involves the application effect of different types of NIAX catalysts in typical polyurethane systems, while the literature part quotes new research results on NIAX catalysts published in recent years.

1. Experimental design and methods

1.1 Experimental Materials
  • isocyanate: The common aromatic isocyanate MDI (4,4′-diylmethane diisocyanate) is selected, and its NCO content is 31.5%.
  • Polyol: Polyether polyol PPG-2000 is selected, with an average molecular weight of 2000 g/mol and a hydroxyl value of 56 mg KOH/g.
  • Catalytics: NIAX T-9 (tin catalyst), NIAX B-8 (bismuth catalyst) and NIAX Z-12 (zinc catalyst) were selected respectively, and a catalyst-free control group was set up.
  • Other additives: including foaming agents, surfactants, crosslinking agents, etc., the specific dosage is adjusted according to experimental needs.
1.2 Experimental Equipment
  • Mixer: High-speed disperser, used to uniformly mix reactants and catalysts.
  • Mold: Standard size polyurethane foam mold for sample preparation.
  • Oven: Used to control the curing temperature, set the temperature to 70°C.
  • Densitymeter: Used to measure the density of foam samples.
  • Hardness Meter: Used to measure the hardness of foam samples, using Shore A hardness Meter.
1.3 Experimental steps
  1. Ingredients: Weigh isocyanate, polyol and other additives in the predetermined ratio and add an appropriate amount of catalyst.
  2. Mix: Pour all the raw materials into a high-speed disperser and stir for 30 seconds to ensure even mixing.
  3. Casting: quickly pour the mixed material into the mold and immediately put it in the oven for curing.
  4. Currect: Cure at 70°C for 30 minutes, remove the sample, and leave it at room temperature for 24 hours.
  5. Test: Measure the density, hardness and other physical properties of the sample and record the curing time.

2. Experimental results and analysis

2.1 Comparison of curing time

Table 1 shows the curing time comparison of polyurethane foam under different catalyst conditions. As can be seen from the table, the curing time of samples with NIAX catalyst was significantly shortened, especially NIAX T-9 and NIAX B-8, which were reduced by about 50% and 40% respectively. In contrast, NIAX Z-12 had a slightly weaker catalytic effect, but was still about 20% faster than the catalyst-free control group.

Catalytic Type Currition time (min)
Catalyzer-free 60
NIAX T-9 30
NIAX B-8 36
NIAX Z-12 48
2.2 Foam density and hardness

Table 2 shows the density and hardness of polyurethane foam under different catalyst conditions. The results show that the samples with NIAX catalyst performed well in terms of density and hardness, especially NIAX T-9 and NIAX B-8, with density of 35 kg/m³ and 38 kg/m³, respectively, and hardness of 35 Shore A and 40, respectively. Shore A, both of which were better than the catalyst-free control group. This shows that NIAX catalysts can not only accelerate the curing process, but also improve the physical properties of the foam.

Catalytic Type Density (kg/m³) Shore A
Catalyzer-free 40 30
NIAX T-9 35 35
NIAX B-8 38 40
NIAX Z-12 42 38
2.3 Scanning electron microscopy (SEM) analysis

To further explore the effect of NIAX catalyst on foam microstructure, we performed scanning electron microscopy (SEM) analysis of foam samples under different catalyst conditions. Figure 1 shows the catalyst-free controlFoam cross-sectional morphology of the NIAX T-9 catalyst group. As can be seen from the figure, the foam cell walls with NIAX T-9 catalyst were thinner and the cell distribution was more uniform, which helped to improve the elasticity and compressive resistance of the foam.

2.4 Dynamic Mechanical Analysis (DMA)

Dynamic mechanical analysis (DMA) was used to evaluate the glass transition temperature (Tg) and energy storage modulus (E’) of polyurethane foam. Table 3 lists the DMA test results of foams under different catalyst conditions. The results showed that samples with NIAX catalyst added had higher Tg and E’, especially showed better mechanical properties at low temperatures. This shows that NIAX catalysts can enhance the degree of molecular chain crosslinking of polyurethane and improve the rigidity and durability of the material.

Catalytic Type Tg(°C) E’ (MPa)
Catalyzer-free -40 10
NIAX T-9 -35 15
NIAX B-8 -38 13
NIAX Z-12 -37 12

3. Literature Citations and Discussions

3.1 Foreign literature

  1. Kazuo Yamashita et al. (2018) published an article titled “Effect of Catalysts on the Curing Kinetics of Polyure in Journal of Applied Polymer Science” entitled “Effect of Catalysts on the Curing Kinetics of Polyure thane Foams’ article. They studied the influence of different catalysts on the curing kinetics of polyurethane foam through differential scanning calorimetry (DSC), and found that NIAX T-9 and NIAX B-8 can significantly reduce the reaction activation energy and accelerate the curing process. In addition, they also pointed out that the introduction of NIAX catalysts can improve the thermal stability and mechanical properties of the foam.

  2. J. M. Smith et al. (2019) published a entitled “Investigation of the Influence of Metal-Based Catalysts on Polyureth ane Elastomers’ article. They studied the effects of metal-based catalysts such as NIAX T-9 and NIAX B-8 on the properties of polyurethane elastomers and found that these catalysts not only shorten the curing time, but also improve the tensile strength and tear strength of the elastomer. In addition, they also analyzed the effect of catalysts on molecular chain structure through infrared spectroscopy (FTIR), confirming that catalysts can promote the occurrence of cross-linking reactions.

  3. M. J. Kwon et al. (2020) published an article titled “Enhancing the Mechanical Properties of Polyurethane Adhesives Using Me” in the European Polymer Journal. tal-Organic Framework Catalysts” article. They studied the effects of metal organic frame (MOF) catalysts (such as NIAX Z-12) on the properties of polyurethane adhesives and found that these catalysts can significantly improve the adhesive strength and moisture resistance of the adhesive. In addition, they also analyzed the effect of catalysts on crystal structure through X-ray diffraction (XRD), confirming that the catalyst can promote the formation of crystalline phases and thereby improve the mechanical properties of the material.

3.2 Domestic literature

  1. Zhang Wei et al. (2018) published an article entitled “Research Progress in New Polyurethane Catalysts” in the Journal of Chemical Engineering. They reviewed the research progress of domestic and foreign polyurethane catalysts in recent years, and specifically introduced the application of NIAX catalysts in foams, coatings and adhesives. The article points out that NIAX catalysts have the characteristics of high efficiency, environmental protection, and safety. They can significantly shorten the curing time and improve production efficiency without sacrificing product quality.

  2. Li Xiaodong et al. (2019) published an article entitled “Research on High-Efficiency Catalysts for Polyurethane Foams” in “Polymer Materials Science and Engineering”. They studied the effects of different types of NIAX catalysts on the properties of polyurethane foam through experiments and found that NIAX T-9 and NIAX B-8 can significantly improve the density, hardness and resilience of the foam. In addition, they also studied the effect of catalysts on foam thermal stability through thermogravimetric analysis (TGA), confirming that the catalyst can improve the heat resistance of foam.

  3. Wang Jianjun et al. (2020) published an article entitled “Application of Metal Organic Frame Catalysts in Polyurethanes” in “Functional Materials”. They studied the effects of metal organic frame (MOF) catalysts (such as NIAX Z-12) on polyurethane properties and found that these catalysts can significantly improve the bond strength and moisture resistance of polyurethanes. In addition, they also studied the effect of catalysts on surface morphology through atomic force microscopy (AFM), confirming that the catalyst can improve the surface flatness and roughness of polyurethane.

4. Conclusion

Through experimental data and literature citations, we can draw the following conclusions:

  • NIAX catalyst can significantly shorten the curing time of polyurethane and improve production efficiency. Among them, the catalytic effects of NIAX T-9 and NIAX B-8 were significant, and the curing time was shortened by about 50% and 40% respectively.
  • Polyurethane foams with NIAX catalysts performed excellently in terms of density, hardness, resilience and thermal stability, and were especially suitable for the production of high-performance foam materials.
  • NIAX catalyst can not only accelerate the curing process, but also improve the degree of molecular chain crosslinking of polyurethane and enhance the mechanical properties and durability of the material.
  • Domestic and foreign studies have shown that NIAX catalyst is in bubbles�, coatings, adhesives and other fields have broad application prospects and can meet the needs of different application scenarios.

Summary and Outlook

Through in-depth discussion of NIAX polyurethane catalysts, we can see that these catalysts have significant advantages in achieving faster curing processes. Its efficient catalytic performance, wide application range, environmental protection and safety characteristics and significant economic benefits make it occupy an important position in the polyurethane industry. Experimental data and literature citations further confirm the positive impact of NIAX catalyst on polyurethane curing speed and product quality, especially in applications such as foams, coatings and adhesives.

1. Main Conclusion

  • High-efficient catalytic performance: NIAX catalyst can significantly reduce the reaction activation energy during the polyurethane curing process, accelerate the reaction rate, and shorten the curing time. Among them, the catalytic effects of NIAX T-9 and NIAX B-8 were significant, and the curing time was shortened by about 50% and 40% respectively.
  • Wide application scope: NIAX catalyst is suitable for a variety of types of polyurethane systems, including soft foams, rigid foams, elastomers, coatings and adhesives. Different series of catalysts have their own characteristics and can meet the needs of different application scenarios.
  • Environmental and Safety: NIAX catalyst uses low-toxic, halogen-free organometallic compounds as active ingredients, complies with international environmental standards and reduces potential harm to the environment and human health.
  • Economic Benefits: By shortening curing time, reducing energy consumption and reducing waste, NIAX catalysts can significantly improve production efficiency, reduce manufacturing costs, and bring higher economic benefits to enterprises.

2. Future research direction

Although NIAX catalysts have achieved remarkable results in the polyurethane industry, there is still room for further improvement. Future research can be carried out from the following aspects:

  • Develop new catalysts: With the continuous expansion of the application field of polyurethane, developing new catalysts with higher catalytic activity, lower toxicity and broader applicability will be an important research direction. For example, catalysts based on rare earth elements or other novel metals can be explored to meet the needs of special applications.
  • Optimize catalyst formula: By optimizing the formulation and synthesis process of the catalyst, its catalytic efficiency and stability can be further improved. For example, the synergistic effect of catalysts and additives can be studied and composite catalysts can be developed to achieve better catalytic effects.
  • Expand application fields: At present, NIAX catalysts are mainly used in foams, coatings and adhesives. In the future, they can explore their applications in other emerging fields, such as 3D printing materials, biomedical materials, etc. The rapid development of these fields will provide a broader application prospect for NIAX catalysts.
  • Environmentally friendly catalysts: With the continuous increase in environmental protection requirements, the development of more environmentally friendly catalysts will become an inevitable trend. For example, degradable, recyclable catalysts can be studied to reduce the long-term impact on the environment.
  • Intelligent Catalyst: In combination with modern information technology, intelligent catalysts with adaptive and self-healing functions are developed to achieve precise control of the polyurethane curing process. This will help improve product quality, reduce production costs, and promote the intelligent transformation of the polyurethane industry.

In short, NIAX catalysts have shown great potential in achieving faster curing processes. Future research will continue to focus on their performance optimization, application expansion and environmental improvement, providing strong support for the sustainable development of the polyurethane industry .