Foaming Process of Resol-Type Foam

Continuous-Laminate Process. This process is to foam continuously between two sheets of facing material, employing a laminator (double-belt conveyor). The productivity of this process is the highest, i.e., the yield of raw material is very good, and a high-quality product can be produced. The selection of material, foaming machine and laminator design are very important factors in this process. Excellent quality products have been manufactured by this process in the United States, Western Europe, and Japan. 

In Japan very large quantities of metal-siding board (consisting of metal sheet/phenolic foam/flexible-facing material) are manufactured as exterior materials in budding construction. This material is also manufactured using the same principle as that in the laminate process. 

Spraying Process. This process has been theoretically possible, but practical application has not been realized. In Japan, however, Bridgestone Ltd. has developed (10) a method which makes spraying-inplace possible. By this method three components of resol-type composition can be foamed at a temperature 10°C and higher (preferably at 20°C) with a spray-gun. DetaUed technical data are unavailable, but it is believed that the material as well as foaming machine should have been improved very much. 

---

Foaming Process of Resol-Type Foam. The foaming processes for phenolic foam of both the resol type and benzylic-ether type are the same as those for rigid polyurethane foams. The block-foaming process (slab foaming), pouring process, continuous-laminate process, and spray process are used. See Figure 57. 

---