1, high rate of closed pore
(1), polyether polyol: high proportion of ethylene oxide, high activity, more occurring in the replacement of polyether polyol with different activities.
(2), the process formula: stannous octanoate dosage, high activity of isocyanate, large cross-linking, fast cross-linking speed, too much amine and physical blowing agent; resulting in low internal pressure of foam, foam elasticity can not be opened when the TDI index is too large, will also lead to high closed porosity.
2、Shrinkage (gel speed is greater than foaming speed)
(1), high closed pore rate, shrinkage when cooling;
(2), process conditions: low temperature, low material temperature;
(3), process formula: excessive silicone oil, excessive physical foaming agent, TDI index is too low.
3、Inside crack
(1), process conditions: low temperature, high temperature of reaction center;
(2), the process formula: TDI index is low, more tin, early foaming strength is high;
(3), high activity of silicone oil, less dosage.
4、Top crack (unbalanced speed of aerogel)
(1), process conditions: low temperature, low material temperature;
(2), the process formula: catalyst dosage is not enough, amine dosage is less, silicone oil quality is not good.
5, the bottom corner of the crack (too much amine, foaming speed is too fast)
Surface macropore: excessive amount of physical foaming agent, silicone oil and catalyst quality is poor.
6、Poor low temperature performance of foam
Poor intrinsic quality of polyether polyol, in the same hydroxyl value, low functionality, unsaturation, the same amount of tin, TDI index is low. 7、Poor ventilation
(1), climate conditions: low temperature
(2), raw materials: high polyether polyol, high activity of silicone oil;
(3), process formula: more tin, or the same amount of tin with less water and amine content, TDI index is high.
8、Different inverse elasticity
(1), raw materials: high activity of polyether polyol, small relative molecular mass, high activity of silicone oil;
(2), process formula: large amount of silicone oil, more tin, more water in the same amount of tin, high TDI index.
9、Poor tensile strength
(1), raw materials: too much low molecular polyether polyol, the same hydroxyl value of low functionality;
(2), the process formula: less tin gel reaction is not good, in the same amount of tin, TDI index is high, less water cross-linking degree is low.
10、Smoke when foaming
Excess amine prompted by the reaction between water and TDI gives off a lot of heat, low boiling point material evaporation and smoke. If it is not scorched heart, the smoke is mostly composed of TDI, low boiling point substances and monomeric naphthenes in polyether polyol.
11、Foam with white rib
Foam and gel reaction speed is fast, in the continuous foam transfer speed is slow, the local extrusion and generation of dense layer, the phenomenon of white tendons. The transfer speed should be increased in time, or the material temperature should be lowered, and the catalyst should be reduced.
12、Crispy foam
There is more water in the formula, the generation of diurea has not been dissolved in silicone oil, poor tin catalyst, cross-linking reaction is not sufficient, small relative molecular mass polyether polyol content reaction temperature is too high, the ether bond breakage reduces the foam strength.
13、Foam density is lower than the set value
Foam index is too big because of inaccurate measurement, high temperature and low air pressure.
14、The foam has bottom skin, side skin, bottom step cavitation
Tin polyamine less, slow foaming speed, gel speed, in continuous foaming with temperature too low.
15、Large elongation rate
(1), raw materials: polyether polyol with high activity and small functionalities.
(2), process formula: TDI index low cross-linking deficiency, more tin, more silicone oil.
