Introduction: Development status of polyurethane spray foam technology
In the context of increasingly stringent global building energy conservation and environmental protection requirements, polyurethane spray foam as an efficient thermal insulation material, its application range is constantly expanding. At present, there are two main technical routes on the market: traditional water foaming systems and emerging HFO(hydrofluoroolefin) foaming systems. As a professional manufacturer of polyurethane catalysts, we will thoroughly analyze the technical characteristics of the two systems, the performance differences, and how to choose the right catalyst to optimize the performance of the system.
Water foam polyurethane spray foam system details
Basic principles and chemical reactions
The Water-Blown System (WBA) is one of the most traditional and mature foaming technologies in the polyurethane industry. The basic principle is to use water to react with isocyanate (-NCO) to produce carbon dioxide (CO₂) as a foaming gas:
R-NCO + H₂O → R-NH₂ + CO₂↑
This reaction simultaneously creates a polyurea structure that provides partial rigidity to the foam. Advantages of the water foaming system include:
- Cost advantage: Water is the most economical blowing agent
- Environmental protection: Zero ODP(ozone depletion potential), low GWP(global warming potential)
- Mature process: decades of application history, perfect process parameters
Typical application field
1. Building insulation: on-site spraying insulation of walls and roofs
2. Cold chain logistics: heat insulation of refrigerated trucks and cold storage
3. Industrial pipelines: anti-corrosion and insulation of petrochemical pipelines
Performance characteristics
- Density range: usually 30-50kg/m³
- Thermal conductivity: 0.022-0.028W/(m·K)
- Obturator rate: 90-95%
- Dimensional stability: ≤1.5%(70℃, 48h)
Analysis of HFO foaming polyurethane spray foam system
New generation of physical blowing agent technology
HFO(hydrofluoroolefin) blowing agent is a fourth-generation physical blowing agent developed in recent years, representing products such as HFO-1233ZD (E) and HFO-1336MZZ (Z). Compared to traditional HCFCS and HFC blowing agents, HFO has:
- Very low GWP: usually <10, much lower than HFC-type blowing agents
- Zero ODP: does not damage the ozone layer
- Excellent thermal insulation: gas phase thermal conductivity is lower than CO₂
Chemical reaction characteristics
As a physical blowing agent, HFO mainly relies on its vaporization expansion to produce foam structure, but it still requires water to participate in part of the chemical reaction to provide additional foaming power:
Main reaction: HFO vaporization expansion
Side reaction: H₂O + -NCO → CO₂ + polyurea
Main application scenarios
1. High-end building insulation: Green building projects with strict environmental protection requirements
2. Electrical insulation: refrigerator, water heater and other household appliances insulation layer
3. Aerospace: Special applications with demanding weight and performance requirements
Performance characteristics
- Density range: 28-45kg/m³
- Thermal conductivity: 0.018-0.022W/(m·K)
- Obturator rate: 92-97%
- Dimensional stability: ≤1.2%(70℃, 48h)
The key role of catalysts in both systems
Properties of MXC-70 catalyst
MXC-70 is a highly efficient, low-odor amine catalyst specifically developed for polyurethane spray foam with the following characteristics:
- Low odor: Improve the working environment and meet strict workplace standards
- Smooth foaming curve: provides a balanced gel and foaming balance to reduce surface defects
- Enhanced adhesion: Especially optimized for the adhesion of various substrates (metal, wood, concrete, etc.)
- Wide applicability: Compatible with water foaming and HFO foaming systems
Technical parameters:
- Chemical type: tertiary amine complex
- Activity: Medium high
- Recommended usage: 0.3-1.2php
- Applicable pH range: 7-10
Catalytic mechanism in water foaming system
MXC-70 catalyzes the following reactions in water foaming systems:
1. Reaction of water with isocyanate (foaming reaction)
2. Reaction of polyols with isocyanates (gel reaction)
3. Crosslinking reaction (increase foam strength)
Its unique molecular structure can maintain moderate activity at the initial stage of foaming, and provide sufficient gel power at the later stage of foaming, so as to obtain a uniform foam with a flat surface.
Optimization role in HFO system
HFO systems often face the following challenges due to differences in the physical properties of blowing agents:
- The foam and gel balance is difficult to control
- Slow surface curing
- Substrate bonding is unstable
The MXC-70 optimizes HFO system performance by:
1. Adjust foaming rise curve to match HFO vaporization characteristics
2. Enhance post-curing to improve surface quality
3. Improve interface activity and enhance substrate wettability
System selection recommendations and application cases
How to choose the right foaming system
1. Consider environmental regulatory requirements
- Europe and the United States strict market: priority HFO system
- Developing countries: Water foaming systems remain competitive
2. Evaluate performance requirements
- Ultra-low thermal conductivity: Select HFO system
- High strength requirements: Water foaming systems may be preferable
3. Cost considerations
- Budget limited project: Water foaming system
- High-end projects: The additional cost of HFO systems can be accepted
Successful application case
Case 1: A green building project (Water foaming system)
- Use MXC-70 catalyst in 0.8php
- Achieved thermal conductivity 0.025W/(m·K)
- Construction efficiency increased by 15%
- LEED certified
Case 2: High-end Refrigerator production Line (HFO System)
- MXC-70 mixed with special catalyst
- Thermal conductivity reduced to 0.019W/(m·K)
- Foam density reduced by 12%
- Annual energy cost savings of about $80,000
Future development trend and technology outlook
1. Continuous optimization of water foaming system
- Improved performance with new catalysts
- Reduce water usage to reduce brittleness
- Development of high flame retardant formulations
2. Progress of HFO technology
- Development of lower cost HFO blowing agents
- Improved process adaptability
- Improve system stability
3. Development of catalyst technology
- Reactive catalyst (VOC reduction)
- Intelligent catalytic system (adaptive to different conditions)
- Multifunctional catalyst (catalytic + flame retardant + stable)
Conclusion and suggestion
Water foaming and HFO foaming systems each have advantages, and the choice depends on the specific application needs, environmental requirements and cost considerations. No matter which system is used, choosing the right catalyst is key to ensuring product quality and production efficiency.
MXC-70 is a highly effective, market-proven catalyst with the following applications:
- Provides a balanced foam/gel balance for water foaming systems
- Solve the surface curing and bonding challenges of HFO systems
- Low odor features improve working environment
- Improve production efficiency and product consistency
Post time: Apr-15-2025