| 摘要 |
<p>Mfr. of a thermoplastics sheet composed of several sections which are joined together by so-called integral hinges is claimed. One section of the complete, flat, sheet is clamped into a bending device whilst the adjoining section is bent over by an angle which pref. exceeds 90 degrees, and then bent back at least into its initial position. The so-stressed hinge zone is molecularly oriented and thus doubles as hinge which will withstand repeated flexing. Suitable thermoplastics include crystalline polyethylene, polypropylene, polyamide, polyester, polyacetal.</p> |
