Vinylidene fluoride resin monofilament and process for producing the same

Abstract

A monofilament obtained by smelt-spinning and stretching of a vinylidene fluoride resin is subjected to a high-temperature relaxation treatment for an extremely short period of 0.05-0.5 sec. within a high-temperature heating oil bath at a temperature of 140-175° C., thereby producing a vinylidene fluoride resin monofilament, which comprises a vinylidene fluoride resin having an inherent viscosity of at least 1.40 dl/g, and has a knot strength (JIS L1013) of at least 600 MPa and excellent anti-twist property represented by a twist index of at least 0.90 when measured after the monofilament being subjected to application for 1 minute of a tensile load equal to approximately 50% of a maximum tensile load (JIS K7113), removal of the load, and standing for 3 hours.

1 . A vinylidene fluoride resin monofilament, comprising a vinylidene fluoride resin having an inherent viscosity of at least 1.40 dl/g, and having a knot strength (JIS L1013) of at least 600 MPa and a twist index of at least 0.90 when measured after the monofilament being subjected to application for 1 minute of a tensile load equal to approximately 50% of a maximum tensile load (JIS K7113), removal of the load, and standing for 3 hours.  
   
   
       2 . A monofilament according to  claim 1 , having a twist index of at least 0.92.  
   
   
       3 . A monofilament according to  claim 1 , having a core-sheath laminar structure comprising a core having a higher inherent viscosity and a sheath having a lower inherent viscosity.  
   
   
       4 . A monofilament according to  claim 1 , having a knot elongation of 16-35% and a Young's modulus of 1500-3500 MPa.  
   
   
       5 . A monofilament according to  claim 1 , having a diameter of 52 μm-1.81 mm.  
   
   
       6 . A process for producing a vinylidene fluoride resin monofilament, comprising: subjecting a vinylidene fluoride resin monofilament having an inherent viscosity of at least 1.40 dl/g after melt-spinning and stretching to a high-temperature relaxation treatment for an extremely short period of 0.05-0.5 sec. within a high-temperature heating oil bath at a temperature of 140-175° C.  
   
   
       7 . A process according to  claim 6 , wherein the vinylidene fluoride resin monofilament has been stretched at a ratio of at least 5 times prior to the relaxation heat treatment.  
   
   
       8 . A process according to  claim 6 , wherein a relaxation of 1-14% is given in the relaxation heat treatment.  
   
   
       9 . A process according to  claim 6 , wherein the heating oil bath comprises glycerin, silicone oil or polyethylene glycol.  
   
   
       10 . A fishing line, comprising a vinylidene fluoride resin monofilament according to  claim 1 .  
   
   
       11 . A fishing line according to  claim 10 , in a form of being wound about a spool.