| 摘要 |
1,087,036. Films; moulding thermoplastic material. UBE-NITTO KASEI CO. Ltd. Nov. 11, 1964 [April 6, 1964], No. 45964/64. Headings B5A and B5B. [Also in Division D1] An elongated shaped article is made by meltextrusion of a blend of at least two different kinds of thermoplastic synthetic resins, followed by longitudinal stretching, thereby orienting the article in the extrusion direction, followed by a mechanical treatment so as partly to disorder the orientation. Blends specified include (1) 20-15% polyethylene and 80-85% isotactic polypropylene, (2) 20-15% isotactic polypropylene and 80-85% polyethylene, (vide Example 1), (3) 75% high density polyethylene and 25% of a polyamide (vide Example 2), (4) 50% high density polyethylene, 35% isotactic polypropylene and 15% polyethylene terephthalate (vide Example 3). Melt extrusion may be so as to form a sheet, film, band, tape or monofilament or structure of T-shaped crosssection (vide Example 2). Mechanical treatment may comprise pressing between grooved rollers, or between gears, or beating with hammers, but is preferably effected by compression by at least one pair of rollers having indentations in their surfaces. A pair of rollers having spiral-shaped indentations in two mutually crossing directions (Figs. 2 and 3, not shown) may be used to produce a biaxially oriented band having a multitude of convex and concave patterns on its surface, which is useful in packaging. As shown in Fig. 1a, a molten polymeric blend contained in a cylinder 2 of an extruder 1 is forced through a die 3 having a plurality of nozzles. The extruded bands b pass under a guide roller 5 in a cooling bath 4. The cooled bands pass from the bath 4 over and around nip rolls 6, and at an appropriate distance from the nip rolls there are positioned stretching rolls 7. Between these two pairs of rolls 6 and 7, a heating apparatus 8 having a circulation of hot air, steam or the like heats the bands so that they are molecularly oriented in the direction of extrusion and stretching. The bands then pass between a pair of compression rollers 9 to a wind-up roll 10. Each of the two compression rollers 9 has two sets of helical indentations on its surfaces (as in Fig. 2, not reproduced), in two different directions, the cross-section of the indentations being trapezoid. As the helical pitches of the indentations of the two rollers are not identical, the parts of the bands which have been contacted by the convex parts of the two rollers are subjected to the strongest compression, thereby forming convex and concave patterns of random arrangement. Preferably, the compression pressure upon the bands is 5 kg. per sq. mm., the velocity of passage is in the range of from 40 m. per min. to 150 m. per min., and the degree of stretch is in the range of from 15 to 100%, most preferably about 20%.
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