The problems with organic blowing agents are:

(1), the amount of gas is small, generally only 15%-30% of inorganic foaming foaming agent, the amount of residue is large, including water and volatile substances, sometimes there are odor and surface frosting:

(2) The decomposition of foaming has a large calorific value and is difficult to remove. Especially in the case of a large wall thickness of the product, the internal plastic is overheated and decomposed to lower the performance;

(3), foaming agents are almost all flammable, low decomposition temperature, storage and use should be careful.

The ideal chemical blowing agent should meet the following requirements:

1. The temperature range at which the gas is decomposed should be narrow.

2, the speed of gas release should be fast, the gas rate should be able to control.

3. The released gas should be non-toxic, non-corrosive, non-combustible. Nitrogen is best used as carbon dioxide. Nitrogen dioxide can also be tested, but the nitrogen dioxide gas is corrosive.

4, chemical foaming agent should be easy to disperse evenly, can be the best blend with plastics.

5, cheap, stable storage, non-toxic.

6. The residue after decomposition should be non-toxic, colorless, odorless, and will not affect the physical, chemical and mechanical properties of the plastic, and it is chemically inert and does not affect the melting rate and solidification of the plastic.

7. There should be no large amount of heat release during decomposition, which does not affect the melting and solidification of plastics.

8. The residue after decomposition is compatible with the resin, and no residue blooming or dialysis occurs.

9. The decomposition temperature of the blowing agent should be consistent with the melting temperature of the resin.

The above is the key point of selecting a blowing agent, which is selected according to the required conditions.