May 11, 2021
1. Coke core (the temperature of the reaction center exceeds the antioxidant temperature of the raw material)
(1) The quality of polyether polyols is problematic: the moisture in the product exceeds the standard during the production, storage and transportation, the content of peroxides and low-boiling impurities is too high, the concentration of metal ions is too high, and the type and concentration of antioxidants are inappropriate;
(2) Formula: In the low-density formula, the TDI index is too high, the ratio of water to the physical foaming agent in the foaming agent is improper, the amount of physical foaming agent is too small, and the water is excessive;
(3) Climate influence: summer temperature is high, heat dissipation is slow, material temperature is high, air humidity is high, and the reaction center temperature exceeds the antioxidant temperature;
(4) Improper storage: When the TDI index increases, the accumulated heat energy during post-curing will increase, causing the internal temperature to rise and coke.
2. Large compression deformation
(1) Polyether polyol: functionality is less than 2.5, the proportion of ethylene oxide is greater than 8%, there are many small molecular components, and the degree of unsaturation is greater than 0.05 mo1/kg;
(2) Process conditions: The temperature of the reaction center is too low or too high, the post-curing is not good, the reaction is not complete, or there is partial coke; (3) Process formula: TDI index is too low, silicone oil stannous octoate is excessive, foam ventilation is low , The closed cell rate is high.
3. The foam is too soft (the hardness decreases under the same density)(1) Polyether polyol: low functionality, low hydroxyl value, high relative molecular mass;(2) Process formula: The amount of stannous octoate is small, the gel reaction speed is slow, and the amount of tin is the same, the amount of water is small, the physical foaming agent is large, the activity of silicone oil is high, the dosage is large, and the TDI index is low.