| 摘要 |
Foam board having a core of plastics foam, especially polyurethane or polyisocyanurate, between flexible sheets is made by continuously advancing two facing sheets in spaced opposed transversely parallel disposition; depositing a liquid foam- forming mixture onto at least one sheet, usually the lower sheet; bringing the sheets into proximity and passing them between foam- constricting members forming a metering gap to spread the mixture across the width of the sheets and fully occupy the space therebetween; thereafter transporting the facing sheets while allowing the foam-mix to expand and cure. To improve the squareness of the edges of foam board which otherwise tend to be tapered, one or both facing sheets are folded at one or both edges prior to their passage through the metering gap and the folded edge or edges are allowed to recover in controlled manner subsequent to passage through the metering gap. |
