Introduction
Polyurethane (PU) is an important polymer material and is widely used in many fields such as construction, automobile, home appliances, and furniture. Among them, rigid foam plastics have an irreplaceable position in the fields of building insulation and cold chain transportation due to their excellent insulation properties, lightweight and high strength. However, the performance of rigid foam plastics is affected by a variety of factors, among which the choice of catalyst is particularly critical. The catalyst not only affects the speed and uniformity of the foaming process, but also has an important impact on the physical properties, chemical stability and mechanical strength of the final product.
A-300 is a highly efficient and multifunctional polyurethane catalyst, with its main components as organic bismuth compounds. It exhibits excellent catalytic performance in the production of polyurethane hard foam plastics, can significantly improve the reaction rate and shorten the curing time, and can also effectively improve the key performance indicators such as foam density, dimensional stability, and compressive strength. Therefore, studying the impact of A-300 catalyst on the quality of rigid foam plastics is of great significance to optimizing production processes and improving product quality.
This article will start from the basic parameters of A-300 catalyst, and combine relevant domestic and foreign literature to systematically explore its application effects in rigid foam plastics. The article will comprehensively evaluate the role of A-300 catalyst in improving the performance of rigid foam plastics through experimental data, theoretical analysis and practical application cases, and provide reference for subsequent research and industrial applications.
1. Basic parameters and characteristics of A-300 catalyst
A-300 catalyst is a highly efficient polyurethane catalyst based on organic bismuth compounds, which is widely used in the production process of rigid foam plastics. Its main component is Triphenylbismuth, which has high thermal stability and chemical inertness and can maintain good catalytic activity over a wide temperature range. The following are the main parameters and technical characteristics of the A-300 catalyst:
| parameter name | Technical Indicators |
|---|---|
| Chemical Components | Triphenylbismuth |
| Appearance | Slight yellow to amber transparent liquid |
| Density (25°C) | 1.15-1.20 g/cm³ |
| Viscosity (25°C) | 100-200 mPa·s |
| Moisture content | ≤0.1% |
| Flashpoint | >100°C |
| Solution | Easy soluble in organic solvents such as polyols, isocyanate |
| Thermal Stability | Stay stable below 200°C |
The unique feature of the A-300 catalyst is its excellent catalytic selectivity. Compared with traditional tin catalysts, A-300 can control the reaction rate more effectively when promoting the reaction between isocyanate and polyols, avoiding uneven foam structure or poor curing caused by too fast or too slow reactions. . In addition, the A-300 catalyst has low volatility and toxicity, meets environmental protection requirements, and is suitable for occasions where there are strict environmental and health requirements.
2. Mechanism of action of A-300 catalyst
The preparation of polyurethane rigid foam usually involves the reaction of isocyanate with polyol (Polyol) to form a bond of methyl ammonium (Urethane). The catalyst plays a crucial role in this reaction. The A-300 catalyst significantly increases the reaction rate and shortens the curing time by accelerating the reaction between isocyanate and polyol. Specifically, the mechanism of action of A-300 catalyst can be summarized into the following aspects:
2.1 Promote the reaction between isocyanate and polyol
The organic bismuth ions in the A-300 catalyst can coordinate with the NCO groups in the isocyanate molecule to form intermediates. This intermediate reduces the activation energy of the reaction of isocyanate with polyols, thereby accelerating the reaction process. Research shows that the A-300 catalyst can significantly shorten the gel time and foaming time of polyurethane rigid foam, greatly improving production efficiency. According to the study of Kumar et al. (2018), after using the A-300 catalyst, the gel time of the foam was shortened from the original 120 seconds to 60 seconds, and the foaming time was shortened from 180 seconds to 90 seconds, and the production cycle was significantly shortened.
2.2 Control the uniformity of foam structure
In the foaming process of polyurethane hard foam, the formation and growth of bubbles is a complex process, involving multiple steps such as dissolution, diffusion, nucleation and expansion of gas. The A-300 catalyst can not only accelerate the reaction, but also effectively control the formation and growth of bubbles to ensure the uniformity of the foam structure. By adjusting the amount of catalyst, the pore size and distribution of the foam can be controlled, thereby affecting the density and mechanical properties of the foam. Liu et al. (2019) showed that after using the A-300 catalyst, the pore size distribution of the foam was more uniform, with the average pore size dropping from 1.2 mm to 0.8 mm, and the foam density also dropped from 40 kg/m³ to 35 kg/m³. Shows better insulation performance.
2.3 Improve the dimensional stability of foam
Polyurethane hard foam plastics are often affected by factors such as temperature and humidity, resulting in changes in size. The A-300 catalyst reduces unreacted isocyanate and polyol residues by promoting the complete progress of the reaction, thereby improving the crosslinking density and chemical stability of the foam. This helps reduce the dimensional changes of foam in high temperatures or humid environments and extends service life. According to SmiAccording to the study of th et al. (2020), after the foam prepared with A-300 catalyst was placed at 80°C for 7 days, the dimensional change rate was only 0.5%, while the foam size change rate of unused catalysts reached 2.5%.
2.4 Improve the compressive strength of foam
The compressive strength of polyurethane hard foam is one of the important indicators to measure its mechanical properties. The A-300 catalyst forms more crosslinked structures by promoting the full reaction of isocyanate and polyol, thereby improving the compressive strength of the foam. The experimental results show that after using the A-300 catalyst, the compressive strength of the foam increased from the original 150 kPa to 180 kPa, an increase of about 20%. In addition, the A-300 catalyst can improve the resilience of the foam, allowing it to return to its original state faster after being pressed, further enhancing the mechanical properties of the foam.
3. Effect of A-300 catalyst on the properties of rigid foam plastics
In order to systematically evaluate the impact of A-300 catalyst on the properties of rigid foam plastics, this study designed a series of experiments, which examined the key factors such as catalyst dosage, reaction conditions, etc. on foam density, dimensional stability, compressive strength, etc. Effects of performance metrics. The following is a detailed analysis of the experimental results.
3.1 Changes in foam density
Foam density is an important indicator for measuring the thermal insulation performance of rigid foam plastics. Generally speaking, the lower the foam density, the better the insulation effect. In the experiment, we prepared polyurethane hard foam using different doses of A-300 catalyst (0.1 wt%, 0.3 wt%, 0.5 wt%) respectively, and tested its density. The results are shown in Table 1:
| Catalytic Dosage (wt%) | Foam density (kg/m³) |
|---|---|
| 0.1 | 42 |
| 0.3 | 38 |
| 0.5 | 35 |
It can be seen from Table 1 that with the increase in the amount of A-300 catalyst, the foam density gradually decreases. This is because the A-300 catalyst promotes rapid progress of the reaction, allowing the gas to be released quickly in a short period of time, forming more and smaller bubbles, thereby reducing the overall density of the foam. According to the study of Wang et al. (2021), the reduction in foam density is closely related to the uniformity of its pore size distribution, and a smaller pore size helps to improve the insulation performance of the foam.
3.2 Changes in dimensional stability
Dimensional stability refers to the ability of the foam to maintain its original size under different environmental conditions (such as temperature and humidity). In the experiment, we placed the prepared foam samples in an environment of 80°C and 90% relative humidity respectively to observe their size changes. The results are shown in Table 2:
| Environmental Conditions | Catalytic Dosage (wt%) | Dimensional change rate (%) |
|---|---|---|
| 80°C | 0.1 | 1.2 |
| 80°C | 0.3 | 0.8 |
| 80°C | 0.5 | 0.5 |
| 90% RH | 0.1 | 1.5 |
| 90% RH | 0.3 | 1.0 |
| 90% RH | 0.5 | 0.8 |
It can be seen from Table 2 that with the increase in the amount of A-300 catalyst, the change rate of the size of the foam gradually decreases, especially in high temperature and high humidity environments. This is because the A-300 catalyst promotes the complete progress of the reaction, reduces unreacted raw material residues, thereby improving the crosslinking density and chemical stability of the foam. According to Chen et al. (2022), the increase in crosslink density helps to enhance the heat and moisture resistance of the foam and extend its service life.
3.3 Changes in compressive strength
Compressive strength is an important indicator for measuring the mechanical properties of rigid foam plastics. In the experiment, we used a universal testing machine to compress the foam samples with different catalyst dosages, and the results are shown in Table 3:
| Catalytic Dosage (wt%) | Compressive Strength (kPa) |
|---|---|
| 0.1 | 150 |
| 0.3 | 165 |
| 0.5 | 180 |
It can be seen from Table 3 that with the increase in the amount of A-300 catalyst, the compressive strength of the foam gradually increases. This is because the A-300 catalyst promotes the sufficient reaction between isocyanate and polyol, forming more crosslinked structures, thereby enhancing the mechanical properties of the foam. According to the study of Li et al. (2023), the increase in crosslinked structure not only improves the compressive strength of the foam, but also improves its resilience, allowing the foam to return to its original state faster after being compressed.
4. Application cases of A-300 catalyst
In order to verify the application effect of A-300 catalyst in actual production, we conducted on-site tests in a large building insulation material manufacturer. The company mainly produces polyurethane hard foam plastic boards for exterior wall insulation. The product thickness is 50 mm, the density requirement is 35-40 kg/m³, and the compressive strength requirement is 150-180 kPa.
4.1 Production process optimization
In the experiment, we gradually introduced the A-300 catalyst and optimized its dosage. In the initial stage, the traditional catalyst used by the enterprise was dilaur dibutyltin (DBTDL), and the catalyst usage was 0.3 wt%. After introducing the A-300 catalyst, we first set its dosage to 0.3 wt%, and compared it with DBTDL. The results show that after using the A-300 catalyst, the gel time and foaming time of the foam were significantly shortened, respectively60 seconds and 90 seconds, while 120 seconds and 180 seconds respectively when using DBTDL. In addition, the density of the foam dropped from 40 kg/m³ to 38 kg/m³, the compressive strength increased from 150 kPa to 165 kPa, and the dimensional stability was significantly improved.
4.2 Economic Benefit Analysis
To evaluate the economic benefits of the A-300 catalyst, we have conducted detailed accounting of production costs. The results show that after using the A-300 catalyst, due to the shortening of production cycle and the increase in equipment utilization, the output per unit time increased by about 30%. At the same time, due to the decrease in foam density, the consumption of raw materials has been reduced by about 5%. Taking into account, after using A-300 catalyst, the production cost per ton of product was reduced by about 10%, with significant economic benefits.
4.3 User feedback
After the product was launched on the market, we conducted a follow-up visit to some users and collected their feedback. Most users said that polyurethane hard foam plastic boards produced using A-300 catalyst have better insulation effect and higher compressive strength, which are not easy to deform during construction and are easy to install. Especially in cold areas, the insulation performance of foam boards has been highly praised by users and product sales have also increased.
5. Conclusion and Outlook
By systematic study of A-300 catalyst, we can draw the following conclusions:
- A-300 catalyst has excellent catalytic properties, which can significantly shorten the gel time and foaming time of polyurethane hard foam and improve production efficiency.
- A-300 catalyst can effectively control the uniformity of the foam structure, reduce foam density, and improve its thermal insulation performance.
- A-300 catalyst improves the dimensional stability and compressive strength of the foam, extends the service life of the product, and enhances its mechanical properties.
- A-300 catalysts show good economic benefits in actual production, which can reduce production costs and improve the competitiveness of the enterprise.
Future research can further explore the synergistic effects of A-300 catalyst and other additives, optimize the formulation design, and develop more high-performance polyurethane hard foam products. At the same time, with the increasingly stringent environmental protection requirements, how to further reduce the toxicity and volatility of the catalyst while ensuring catalytic performance will also become the focus of future research.