久久爱免费人成精品

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            Common problems and solutions of soft foam sponge
            Time:2020/4/23 10:02:11    

            1. High closed cell rate 

             

            (1)Polyether polyol: high proportion of ethylene oxide, high activity, and mostly occurs when replacing polyether polyols with different activities;

            (2) Process formula: the dosage of stannous octoate is high, the isocyanate activity is high, the degree of crosslinking is large and the speed is fast, too much amine and physical blowing agent.

            As a result, the internal pressure of the foam is low. The foam cannot be opened when the foam is elastic ,The closed cell rate will also be high if the TDI index is too large.

             

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

             

                (1) The closed cell rate is high and shrinks when cooling;

            (2) Process conditions: low temperature and low material temperature;

            (3) Process formula: excessive silicone oil, excessive physical blowing agent, and low TDI index.

             

            3. Internal crack

             

                (1) Process conditions: low temperature and high temperature of reaction center ;

                (2) Process formula: low TDI index, more tin, high strength in the early foaming.

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

             

            4. Top crack (unbalanced speed of aerogel)

             

                (1) Process conditions: low temperature and low material temperature;

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

                

            5. Bottom corner cracking (too much amine and foaming speed is too fast)

             

                Large pores on the surface: the physical foaming dose is too large, and the quality of the silicone oil and catalyst is poor.

             

            6. Low temperature of foam with poor performance

             

            The inherent quality of polyether polyols is poor, at the same hydroxyl value, low functionality and high unsaturation, the TDI index is low at the same amount of tin.

             

            7. Poor ventilation

             

            (1) Climatic conditions: low temperature

             

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

            (3) Process formula: when there is more or the same dosage of tin, the content of water and amine is small, and the TDI index is high.

             

            8. Poor rebound

                

            (1) Raw material: Polyether polyol has high activity, small molecular weight and high  activity of silicone oil;

                (2) Process formula: the amount of silicone oil and tin is big, there is more water and the TDI index is higher at the same dosage of tin.

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            久久爱免费人成精品
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