| 摘要 |
1,211,963. Fishing line. SOO VALLEY CO. Inc. 27 Feb., 1969 [15 Nov., 1968], No. 10615/69. Heading A1A. [Also in Divisions B2, B5 and D1] A tapered fishing line is produced by (a) centering in the extrusion orifice of a coating die and drawing through the orifice a continuous flexible filamentous core of uniform diameter, (b) extruding through the orifice at a constant volumetric rate a fused thermoplastic synthetic polymeric material which forms a layer that surrounds and is bonded to the core, the polymeric material having a 'torsional stiffness' of 2,500 to 12,000 p.s.i. (determined by ASTM test method No. D1043-61T) and the core having less stretchability than the coated core from the extrusion orifice in a positive manner at a maximum speed such that the diameter of the coated core is at a minimum, (d) gradually decreasing the speed at which the coated core is withdrawn to draw the core through the orifice at a decreasing speed and to increase the diameter of the coated core, (e) after the coated core issuing from the orifice has attained a predetermined maximum diameter, gradually increasing the speed at which the coated core is withdrawn until the coated core has attained its maximum speed and its minimum diameter, repeating steps (d) and (e) as often as desired, and (f) severing the coated core at the points at which such minimum diameter was attained to produce individual fishing lines each of which tapers at both ends to a tip of such minimum diameter. The coating layer may consist essentially of a polyvinyl plastisol. The coated core upon leaving the extrusion orifice may be heated to further fuse it and then allowed to cool so that the coating layer solidifies and becomes bonded to the core. The core may be a single filament or a multiplicity of filaments which may be parallel, twisted or braided. The core may consist of nylon, "Dacron" (Registered Trade Mark) or natural silk. A primer is preferably applied to the core before it is coated to improve the adhesion of the coating to the core. The primer may consist of a solution of any synthetic resin that is compatible with the coating material. Thus it may consist of a solution of a copolymer of vinyl chloride and vinyl acetate in methyl isobutyl ketone, or of a solution of an acrylonitrile-butadiene copolymer in methyl ethyl ketone or in methyl isobutyl ketone. The coating may consist of polyvinyl chloride (and/or a copolymer of polyvinyl chloride and a small proportion of another monomer such as vinyl acetate) plasticized with a conventional plasticizer for polyvinyl chloride, such as di-octyladipate, containing a stabilizer such as a lead soap. The density of the fishing line produced may be reduced by incorporating in the plastic to be used a conventional blowing agent, or may be increased by incorporating microscopic glass beads, lead shot, or lead oxide particles in the plastic. The use of coatings consisting ethylenevinyl acetate copolymers is disclaimed.
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