| 摘要 |
<p>Thermoplastic honeycomb capable of formation by expansion of a compacted ribbon stack and of repeated dips in resin solution to form densified honeycomb panels is prepared by impregnating a fiber web with a thermoplastic material which has a soluble form and an insoluble form, and is readily converted from the former to the latter. Poly(amide-imide)s are an example of a suitable resin. The invention is particularly useful in forming compacted ribbon stacks of resin-impregnated glass fiber, expanding the stacks at an elevated temperature to a partial expansion sufficient to expose the cell interiors, then dipping the partially expanded stacks in resin solution, removing the solvent from the resulting film and curing the film, then expanding the stacks further at an elevated temperature to their full expansion, following by further dips to the final desired density.</p> |
