What is PU rigid foam
Rigid polyurethane foam is a lightweight, high-strength material that combines thermal insulation, waterproofing, sound insulation, and electrical insulation. It is widely used in the insulation of refrigeration equipment such as refrigerators, cold storage, and refrigerated trucks, as well as in buildings, storage tanks, and pipelines. It can also be used to create wood-like materials and packaging materials.
What is polyurethane flexible foam
Polyurethane flexible foam has the characteristics of low density, good elastic recovery , sound absorption, breathability and heat preservation. It is mainly used as cushioning materials such as seat cushions and mattresses for furniture and transportation. It can also be used in filtration, sound insulation, shock absorption and packaging.
Main Differences Between Rigid and Flexible PU Foam
The difference between PU rigid foam and flexible foam CELLS
Rigid foam: Usually a closed-cell structure. It has excellent thermal insulation, waterproofness and high strength.
Flexible foam: usually has an open-cell structure. It has better elasticity, sound absorption and breathability.
Generally speaking, flexible foam plastics mostly have an open-cell structure, and hard foam plastics mostly have a closed-cell structure, but there are exceptions.
The difference between the APPLICATION of PU rigid foam and flexible foam
Application of PU rigid foam:
- Thermal insulation : refrigerators, cold storages, refrigerated trucks, building exterior walls, roofs and pipe insulation.
- Structural materials: High-density rigid foam can be made into imitation wood and used to make furniture and decorations.
- Others: potting materials, packaging materials, etc.
Application of flexible foam:
- Cushioning and filling: sofas, mattresses, car seat cushions, pillows, toys, etc.
- Filtration and sound absorption: filter materials, sound insulation linings.
- Shockproof and packaging: shockproof materials, packaging materials.
The difference between polyurethane rigid foam and flexible foam RAW MATERIALS
Rigid polyurethane foams are typically produced using high-functionality polyols and isocyanates with a high NCO index, while flexible foams are produced using low-functionality polyols and a low NCO index. Semi-rigid foams, which lie somewhere in between, offer a certain degree of strength and flexibility and are commonly used in automotive interiors and steering wheels.
The difference between polyurethane rigid foam and flexible foam ELSSTICITY
If the elastic modulus is used as the distinction standard, under the standard environment of 23℃ and 50% relative humidity,
Those with an elastic modulus greater than 686 MPa are rigid foam plastics; those with an elastic modulus less than 68.6 MPa are flexible foam plastics; and those between 68.6 and 686 MPa are semi-rigid foam plastics.
The difference between polyurethane rigid foam and flexible foam ACCORDING TO NATIONAL STANDARSD
Foam plastics that are flexible, have very low compression hardness, can return to their original shape after stress is released, and have small residual deformation are flexible foam plastics; foam plastics that are inflexible, have high compression hardness, deform only when stress reaches a certain value, and cannot return to their original shape after stress is released are hard foam plastics.
The difference between polyurethane rigid foam and flexible foam specified by AMERICAN SOCIETY FOR TESTING AND MATERIALS
The distinction between soft and hard foam plastics is that at a temperature of 18-29°C, within 5 seconds, it is made to wrap around a round rod with a diameter of 2.5 cm. If it does not break, it is a flexible foam plastic; otherwise, it is a hard foam plastic.
The difference between polyurethane rigid foam and flexible foam according to ISO STANDARDS
If the compression deformation reaches 50% and the pressure is released, the thickness of the plastic that is reduced by no more than 2% compared with the original thickness is a flexible foam plastic, if it is greater than 10%, it is a hard foam plastic, and if it is between 2% and 10%, it is a semi-hard foam plastic.
Summarize
| project | polyurethane rigid foam | Polyurethane flexible foam |
| Structure Type | Closed-cell structure | Open-pore structure |
| density | Higher | Lower |
| elasticity | Low | high |
| Main performance | Heat preservation, waterproof and high strength | Good elasticity, breathable and sound-absorbing |
| application | Refrigerators, building insulation, imitation wood | Sofas, mattresses, car seats |
While both rigid and flexible polyurethane foams are polyurethane foam materials, their differences in structure and performance give them distinct advantages in various applications. Rigid foam, with its excellent thermal insulation, waterproofness, and high strength, is widely used in refrigerators, cold storage, and building insulation. Flexible foam, with its excellent elasticity, comfort, and breathability, is an ideal material for furniture, automotive interiors, and mattresses. Understanding the differences between the two types of foam can help you select the appropriate foam type for your specific production needs, achieving the optimal balance between performance and cost.