What is the function of high resilience polyether? How can the formula be adjusted based on physical properties?

Application of High Resilience Polyether Formulations:

For high resilience polyether, the most frequently used molecular weights are 5,000 and 6,000. The foam produced from high resilience polyether with a molecular weight of 5,000 does not have as good elasticity as that with a molecular weight of 6,000 and tends to be harder. On production lines with continuous foaming, the high resilience polyether with a molecular weight of 5,000 is more commonly used. Polyether polymers, like ordinary foams, are also white and viscous.

Let's look at the differences between ordinary foam formulations and high resilience formulations. Due to the high reactivity of high resilience polyether, it reacts strongly with TDI, suppressing the reaction between TDI and water. We will analyze each component based on the following formulations:

In the formulations, the PPG (polypropylene glycol) is the same. The TDI index is higher in high resilience polyether formulations, which results in the foam being less elastic and more difficult to open the cells. In contrast, the TDI index varies significantly in ordinary polyether foams.

Now, let's consider high resilience silicone oil. Given the high reactivity of high resilience polyether, the silicone oil used should not be highly reactive. In other words, using ordinary silicone oil for high resilience foam will result in severe closed cells; conversely, using high resilience silicone oil for ordinary foam will cause the foam to collapse because the low reactivity of this silicone oil cannot support the foam structure.

Next, let's look at amines. Both types of foam require amines, with variations in the amount used. Amines are quite reactive.

Now, let's consider tin. Since high resilience polyether is highly reactive, the amount of tin used will be relatively lower.

MC (methylene chloride) is also used in both formulations, but some formulations may omit it depending on the specific situation.

Another major difference is that high resilience polyether formulations use crosslinking agents, which is also due to the high reactivity of high resilience polyether. Can foam be produced without crosslinking agents? Yes, but the resulting foam will not have particularly good elasticity.

Some might ask if adding some high resilience polyether to ordinary foam can improve its elasticity due to its high molecular weight. This idea is feasible but needs to consider the following points:

If the ordinary foam formulation has very low density, do not add high resilience polyether because low-density formulations contain more TDI and water, leading to intense reactions. Adding high resilience polyether would make the reaction even more intense, counterproductive.

If the formulation contains a high amount of water, do not add high resilience polyether, as this could cause significant problems.