The Flame Retardant Performance Of Rigid Polyurethane Foam

The following is the relevant information about the flame retardant performance of rigid polyurethane foam produced by Qingdao Longchangjie:

1.Flame retardant mechanism

·Condensed phase flame retardancy: Some flame retardants can promote the formation of a stable carbon layer on the surface of polyurethane foam when heated. This carbon layer can effectively insulate heat, block oxygen, and inhibit the release of flammable gases, thereby preventing the spread of flames.

· Gas-phase flame retardancy: Flame retardants containing phosphorus, halogens, etc. will decompose at high temperatures to produce free radical scavengers. These substances can react with the free radicals generated during the combustion process, interrupting the combustion chain reaction and achieving the flame retardant effect.

2. Types of flame retardants

· Liquid flame retardants: such as tris (2-chloropropyl) phosphate (TCPP), tris (2-chloroethyl) phosphate (TCEP), etc. They are easy to add to polyurethane raw materials, but there may be problems of migration and volatilization, which affect the flame retardant durability.

·Solid flame retardants: such as aluminium hydroxide, zinc borate, expanded graphite, etc. They usually have high thermal stability and can form a protective carbon layer during combustion, thereby enhancing the flame retardant performance of the material.

3. Methods for improving flame retardant performance

· Add flame retardants: By adding flame retardants containing elements such as phosphorus, nitrogen, and halogen, the flame retardant performance of polyurethane foam is enhanced. For example, adding an appropriate amount of tris (2, 3-dichloropropyl) phosphate can make the oxygen index of rigid polyurethane foam reach above 26.

·Reactive flame retardancy: Introduce flame-retardant elements into the polyurethane molecular chain to prepare polyurethane materials that are inherently flame-retardant. The flame-retardant polyurethane foam prepared by this method has a long-lasting flame-retardant performance and has a relatively small impact on the physical properties of the material.

· Surface treatment: A flame-retardant coating, such as aerogel coating or photothermal curing coating, is applied to the surface of polyurethane foam by coating method to enhance its surface flame-retardant performance.

4. Flame retardant performance evaluation

·Oxygen index test: It measures the minimum oxygen concentration required for a material to burn. The higher the oxygen index, the better the flame retardant performance of the material.

· Conical calorimetry test: Simulate real fire scenarios to evaluate combustion performance parameters of materials such as heat release rate, ignition time, and smoke release.

· Vertical burning test: According to the UL94 standard, evaluate the burning rate and burning grade of the material in the vertical direction.

5. Development Trends

· Environmentally friendly flame retardants: With the enhancement of environmental awareness, the development of low-smoke, low-toxicity, and halogen-free environmentally friendly flame retardants has become a research hotspot.

· Multi-functional integration: Develop polyurethane foam materials with multiple functions such as flame retardancy, heat insulation and sound insulation to meet the needs of different application fields.

· Nanotechnology: Utilizing nanomaterials to enhance the flame retardancy and physical properties of polyurethane foam, such as adding nano-clay and nano-alumina, etc.

In conclusion, the flame retardant performance of rigid polyurethane foam plastics can be enhanced through various methods to meet the safety requirements of different application scenarios. In the future, environmentally friendly flame retardants and multifunctional integrated materials will be important research directions for the flame retardant performance of rigid polyurethane foam.