I. Prepolymer method
The foaming process of prepolymer method is that (white material) and (black material) are first made into prepolymer, and then additives such as water, catalyst and surfactant are added to the prepolymer, which are mixed and foamed at high speed and cured at a certain temperature.
Second, the semi-prepolymer method
The foaming process of semi-prepolymer method is to make a part of polyether polyol (white material) and diisocyanate (black material) into prepolymer, and then add another part of polyether or polyester polyol and diisocyanate, water, catalyst, surfactant and other additives to foam at high speed.
The process flow charts of the above two methods are as follows:
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Thirdly, one-step foaming process.
Polyether or polyester polyol (white material), polyisocyanate (black material), water, catalyst, surfactant, foaming agent, other additives and other raw materials are added in one step and foamed after high-speed mixing.
The block diagram of one-step foaming process is as follows:
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At present, one-step foaming process is widely used. There is also the manual foaming method, which is the simplest method. After all the raw materials are accurately weighed, put them into a container, and then immediately mix them evenly and inject them into a mold or a space that needs to be filled with foam. Note: When weighing, polyisocyanate (black material) must be weighed last.