| 摘要 |
<p>Mfr. of hollow profiles of polygonal cross-section comprises providing a relatively rigid plastic web, pref. of polypropylene, of which the width is equal to the desired length of the profile, with blend lines which extend in the width direction and of which the spacing is equal to the desired distances between profile edges. The web is then coated while flat with a layer of the uncured reinforced cement compsn. of which the thickness is equal to the desired wall thickness of the profile, then folded together with the cement layer along the bend lines into a shape corresponding to the finished profile and fixed in this spape. Finally the cement compsn. is allowed to cure, and the plastic web is removed. Compsn. can be extruded without breaking the glass fibres.</p> |
