| 摘要 |
<p>Fibre reinforced plastics mouldings are produced by impregnating an expanded plastics sheet with a thermosetting resin, forming a laminate of the sheet with a fibrous sheet, compressing the laminate in a mould to transfer the resin into the fibrous sheet, polymerising the resin and demoulding after hardening of the resin. The improvement consists in polymerising the resin by subjecting the laminate to a h.f. electric field after cold compression of the laminate. Process avoids the use of external heat for effecting polymerisation and, therefore, attendant drawbacks e.g., viscosity variations in the resin, air occlusion, separate heating of different parts of complex moulds etc. Heating by dielectric loss is more homogeneous and rapid throughout the thickness of the laminate.</p> |
