The Molded Foam Market
The dominance of the molded foam business by the transportation sector results in a unique commercial structure. The slabstock flexible foam market is highly driven by price, supply reliability, and the mutual interest of a varied and highly fractured foam market to absorb the high-volume output of an asset-driven, concentrated polyurethane building block industry. While the molded foam market is also highly price sensitive, it is equally driven by the competition between commercial relationships. Additionally,
TABLE 7.3 Representative formulation, molding conditions, and properties of a high-resilience TDI foam that might be utilized for a seat cushion in the U.S. transportation market
Note the exceptionally high resilience measured for this formulation.
there is the commercial tension brought on by low-margin large businesses (such as commodity producers) and the high cost of sales needed to supply specialized formulations for specific and niche applications. This conflicting need for price and specialization has resulted in the development of distributors who purchase building blocks directly from the building block manufacturer to service small accounts. Inevitable overlaps form with the range of direct sales from the major manufacturer and the distributors. In addition, specialization has also spawned the creation of formulation houses (or "system houses") that simultaneously purchase polyols and isocyanates from building block manufacturers and at the same time compete with these same feedstock manufacturers at customers using fully formulated systems. In response to these pressures, the large building block manufacturers have evolved by buying or developing their own distributor and formulation (or "system") houses. Figure 7.10 provides a visual map of the relationship between the building block producers, distributors, and the formulation houses.
Pertinent differences relative to the TDI foam of Table 7.3 are the density, resilience, and IFD.
TABLE 7.5 General formulation guidelines for transportation seating molded polyurethane foams according to the isocyanate classification
Clear polyol equivalent % solids in polyol- |
|||
Foam type |
weight (g/eq) |
copolymer blend |
Isocyanate |
Hot cure |
1000 |
0-25 |
TDI |
HR iso blend |
1600-2300 |
5-35 |
TDI/pMDI |
TDI HR |
1600-2300 |
5-35 |
TDI |
MDI HR |
1600-2300 |
0-20 |
pMDI/MDI or prepolymer |
TABLE 7.6 General structure-property relationships for flexible molded polyurethane foams related to choice of polyols
Formulation variable |
Effect |
Increased hydroxyl equivalent weight |
Increased viscosity, increased elongation at break, increased resilience, lower load bearing |
Increased polyol functionality |
Increased viscosity, increased load bearing, lower elongation at break, lower compression set, lower airflow, increased durability |
Lower monol content |
Lower hysteresis, lower compression set, less vibration conduction, increased durability |
FIGURE 7.10 Unique commercial relationships among suppliers to the transportation seating market. This situation is bound to evolve, but which channel prevails will depend on unforeseeable market and macroeconomic factors.