What Is a Polyurethane Sponge?
Polyurethane sponges are made from polymer compounds containing urethane bonds, formed by reacting polyisocyanate with polyol. Known for their ability to absorb, contain, and release liquids, these sponges are molded into porous shapes. They are characterized by excellent thermal insulation and ease of molding, available in soft and hard types.
Uses of Polyurethane Sponge
Soft polyurethane sponges, with lower density, are used in sound-absorbing materials, cushions, clothing, and furniture. High-density variants are used for thermal insulation and buoyancy due to their superior thermal properties. Semi-rigid polyurethane sponges, with high resilience and elasticity, are suitable for furniture, mattresses, and vehicle parts. Other applications include filters and bacterial growth media.
Principle of Polyurethane Sponge
Polyurethane sponges are produced by selecting specific types and additives, including catalysts, blowing agents, foaming agents, and flame retardants. The foaming process creates small, independent bubbles, resulting in sponges with excellent air permeability and drying properties. Soft foams primarily use water as a foaming agent, while rigid foams use hydrocarbon-based agents like HFC compounds and cyclopentane.
Types of Polyurethane Sponge
1. Foamed Polyurethane Sponge
This lightweight and flexible material is made by adding a foaming agent to polyurethane resin, creating a sponge with cushioning properties and heat insulation. It’s used in cushioning, packaging, and construction.
2. High-Density Polyurethane Sponge
High-density polyurethane sponges offer enhanced strength, sound insulation, and vibration absorption. They are used in acoustic rooms, machinery vibration control, and fields requiring shock absorption and durability, like construction and automotive.
3. Structural Polyurethane Sponge
Known for its lightweight and impact resistance, a structural polyurethane sponge is used in construction for earthquake resistance and thermal insulation, in automotive parts for shock absorption, and aircraft for structural strength and vibration absorption.
4. Water-Absorbing Polyurethane Sponge
Designed for efficient water absorption, these sponges are used in kitchen and car wash applications. They are effective in removing dirt and grease, quick-drying, and reusable, making them ideal for household and cleaning products.