Abstract Phenol-aldehyde foams are made by forming first and second mixtures of the reactants of which one contains the phenolic component and the other the formaldehyde component, one or the other containing the catalyst and blowing agent. Adjuvants such as silicone oil may be added to one or the other of the mixtures. When the first and second parts are mixed, they are applied evenly to a conveyor having a nonadherent surface at a temperature favorable to reaction and foam formation. The sheet is shaped to its dimensions between upper and lower conveyors and the surfaces hardened to permit handling without distortion. Drying is by dielectric loss. Total time of manufacture is reduced by the order of 12-15 hours and a better, more uniform, and purer product substantially free of acid and moisture is produced. Novel apparatus is also described.
Apparatus according to claim 1 in which the lower conveyor comprises a series of channel shaped elements.
Claim 2
Dependent Claim
36 words
Apparatus according to claim 1 in which the means to dry the panels comprises an electrode supplied by a high frequency generator and target electrode arranged on opposite sides of the path of the moving panels.
Claim 3
Dependent Claim
30 words
Apparatus according to claim 1 in which the means to dry the panels comprises in cooperative relation a magnetron, wave control means, and a chamber through which the panels pass.
Claim 4
Dependent Claim
41 words
Apparatus according to claim 1 in which the means to dry the panels comprises conveyor means, an enclosure covering the conveyor means, and a high frequency wave generating means acting within the enclosure upon the panels carried by the conveyor means.
Claim 5
Dependent Claim
23 words
Apparatus according to claim 5 in which the generating means includes electrode means disposed on opposite sides of conveyor means supporting the panels.
Claim 6
Dependent Claim
18 words
Apparatus according to claim 5 in which the enclosure includes a wave trap associated with the electrode means.