1. High closed pore rate.

(1) Polyether polyols: high proportion of ethylene oxide, high activity, often occurs in the replacement of polyether polyols with different activities.

(2) process formula: large amount of stannous octanoate, high activity of isocyanate, high cross-linking degree, fast cross-linking speed, excessive amine and physical foaming agent.

As a result, the inner pressure of the foam is low, the foam can not be opened when the elasticity of the foam is large, and the closure rate is high when the TDI index is too large.

2. Shrinkage (gel speed is higher than foaming speed).

(1) High closure rate and shrinkage during cooling.

(2) technological conditions: low air temperature and low material temperature.

(3) process formula: excessive silicone oil, excessive physical foaming agent, low TDI index.

3. Internal crack.

(1) process conditions: low air temperature and high reaction center temperature.

(2) process formula: low TDI index, high tin content and high early foaming strength.

(3) silicone oil has high activity and low dosage.

4. Parietal cleft (unbalanced aerogel velocity).

(1) technological conditions: low air temperature and low material temperature.

(2) process formula: insufficient amount of catalyst, low amount of amine, poor quality of silicone oil.

5. Bottom corner crack (too much amine, foaming speed is too fast).

Surface macropores: excessive physical foaming dose, poor quality of silicone oil and catalyst.

6. Poor performance of foam at low temperature.

The inherent quality of polyether polyol is poor, and the TDI index is low at the same hydroxyl value, low function, high unsaturation and the same tin content.

7. Poor ventilation.

(1) Climatic conditions: low temperature.

(2) Raw materials: high polyether polyol, high silicone oil activity.

(3) process formula: more tin, or the same amount of tin, less water and amine, high TDI index.

8. Poor anti-elasticity.

(1) Raw materials: Polyether polyol has high activity, low molecular weight and high silicone oil activity.

(2) process formula: large amount of silicone oil, more tin, more water and high TDI index at the same amount of tin.