How Does A Foam Machine Work
Taking the production of a foam mattress as an example,
1. First, prepare the raw materials. Mix the polyol, catalyst, blowing agent (water or physical blowing agent), silicone oil (surfactant), and other ingredients according to the recipe in Tank A. Isocyanate is placed in Tank B.
2. Second, set the parameters. The operator enters the recipe on the control panel, including the A/B ratio, the temperature of each ingredient, and the injection volume for each shot.
3. Third, start the cycle. The machine starts, and the metering pump begins operating. Materials A and B circulate under high pressure through the pipes and mixing head until the temperature and pressure reach the set values and stabilize.
4. Next, pour (injection) begins. The mold or production line is positioned. The operator gives the "start" signal. The mixing head moves above the mold, aligning its outlet with the mold cavity. The mixing head valve opens, and the two high-pressure liquid streams collide and mix instantly, injecting a uniform mixture into the mold. The injection volume is precisely controlled by the number of metering pump strokes. After injection, the mixing head valve closes and performs a self-cleaning action.
5. Next comes the chemical reaction and foaming (which occurs automatically in the mold).
The foaming reaction reacts isocyanate with water to produce carbon dioxide (CO₂) gas, which forms countless tiny bubbles within the mixture. These are the "cells" of the sponge.
The gelation reaction reacts isocyanate with polyol to form a polyurethane polymer backbone, which imparts strength to the foam and transforms it from a liquid to a solid state.
These two reactions compete, reaching equilibrium under the action of a catalyst, resulting in a sponge with a specific open/closed cell structure.
6. Finally, aging and post-processing: The foam-filled mold is transported to the aging area, where it fully solidifies and cools. Afterward, the massive sponge block is removed and undergoes finishing processes such as slicing, cutting, and polishing, ultimately becoming the various products we see today, such as mattresses and sofa cushions.
In summary, the polyurethane sponge foaming machine perfectly solves the problem of uniform mixing of polyols and isocyanates, two high-viscosity, fast-reacting liquids, thereby realizing the modern industrial production of polyurethane sponge.
