| 摘要 |
1,268,571. making sheets having hollow projections. EASTMAN KODAK CO. 21 March, 1969 [21 March, 1968], No. 14942/69. Heading B5A. [Also in Divisions B8 and F2] A sheet having hollow projections and suitable for use as a cushioning material (see Figs. 1-4, not shown) is made by passing an apertured mould 56 on a split conveyer 50 through a curtain 48 of molten thermoplastic material to form a coating upon the upper surface of the mould. The mould is subsequently moved on to a vacuum platen where the coating is sucked to the desired depth into the mould apertures to form closed-ended projections. The apertures are preferably polygonal in cross-section, for example triangular, hexagonal or octagonal, and extend at right angles to the plane of the mould. Thermoplastic materials which may be used are, cellulose derivatives; polyacrylates; polyacrylonitriles; polyalkenes; polyamides; polyesters (including polycarbonates); polyethers; polyhydroxy alcohols; polyolefins; polystyrenes; and polyvinyls.
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