Melt spinning resin composition, manufacturing method for same, and fiber manufacturing method

Abstract

The resin composition for melt spinning of the present invention is a filament having a melt viscosity of 250 Pas or less at 200° C. and a shear rate of 0.1 s −1 and a tensile strength of 10 MPa or more. The filament can be produced by forming a molten liquid of a resin composition having a melt viscosity of 250 Pas or less at 200° C. and a shear rate of 0.1 s −1 into a filament shape to provide a formed material, and conveying and concurrently cooling the formed material. The present invention also provides a resin composition for melt spinning being a filament, and a method for producing fiber using a melt spinning apparatus.

1 - 41 . (canceled) 
     
     
         42 . A resin composition for melt spinning, wherein
 the resin composition is a filament and having a melt viscosity of 250 Pas or less at 200° C. and a shear rate of 0.1 s 1  and a tensile strength of 10 MPa or more, and   the filament has a cross-sectional average diameter in a direction perpendicular to a length direction thereof of 1 mm or more and 30 mm or less.   
     
     
         43 . The resin composition according to  claim 42 , wherein the filament has a ratio of a length to a cross-sectional average diameter, length of filament/cross-sectional average diameter of filament, of 20 or more. 
     
     
         44 . The resin composition according to  claim 42 , wherein the resin composition comprises one or more selected from a polyolefin resin and a polyester resin. 
     
     
         45 . The resin composition according to  claim 42 , wherein the resin composition comprises a thermoplastic resin, and the thermoplastic resin comprises a polylactic acid-based resin. 
     
     
         46 . The resin composition according to  claim 45 , wherein the thermoplastic resin comprises one or more selected from a polypropylene resin having a weight-average molecular weight of 150 000 g/mol or less and a polylactic acid-based resin having a weight-average molecular weight of 150 000 g/mol or less. 
     
     
         47 . The resin composition according to  claim 42 , wherein
 the resin composition comprises a thermoplastic resin,   the thermoplastic resin comprises a polypropylene resin, and   the polypropylene resin has a weight-average molecular weight of 1 000 g/mol or more and 150 000 g/mol or less.   
     
     
         48 . The resin composition according to  claim 42 , wherein the resin composition has a breaking strain of 1% or more and 20% or less. 
     
     
         49 . A method for producing fiber using a melt spinning apparatus, wherein
 the melt spinning apparatus comprises:
 a supply port to which a material is supplied; 
 a heating section which melts the material supplied from the supply port, without application of any kneading force; and 
 a nozzle which is in direct communication with the heating section and discharges the material in a molten state, 
   a resin composition used as the material for melt spinning is a filament and has a melt viscosity of 250 Pa·s or less at 200° C. and a shear rate of 0.1 s −1  and a tensile strength of 10 MPa or more, and   the method comprises supplying the filament from the supply port and concurrently discharging the material in a molten state from the nozzle to be spun.   
     
     
         50 . The method for producing fiber according to  claim 49 , wherein
 the melt spinning apparatus further comprises a gas flow spraying section which conveys the material discharged from the nozzle by gas flow, and   the filament is supplied from the supply port, and concurrently the material in a molten state is discharged from the nozzle to be spun, in a state where the gas flow is sprayed from the gas flow spraying section, and/or,   the melt spinning apparatus further comprises an electrically charging device which electrically charges the material discharged from the nozzle, and   the filament is supplied from the supply port, and concurrently the material in a molten state is discharged from the nozzle into an electrical field to be spun, in a state where the electrical field is formed by the electrically charging device.   
     
     
         51 . The method for producing fiber according to  claim 49 , wherein
 the method for producing fiber comprises: forming a molten liquid of a resin composition into a filament shape to provide a formed material; and conveying and concurrently cooling the formed material,   the resin composition has a melt viscosity of 250 Pas or less at 200° C. and a shear rate of 0.1 s −1 , and   the filament having a cross-sectional average diameter in a direction perpendicular to a length direction thereof of 1 mm or more and 30 mm or less is obtained as the material.   
     
     
         52 . The method for producing fiber according to  claim 51 , wherein
 a filament producing apparatus is used,   the filament producing apparatus comprises an extruding section which extrudes the molten liquid from a discharge port to provide the formed material and a conveying section which conveys the formed material, and   a distance between the discharge port and the conveying section is 1 mm or more and 50 mm or less.   
     
     
         53 . The method for producing fiber according to  claim 51 , wherein an extruding section which extrudes the molten liquid from a discharge port, a conveying section which conveys the formed material, and a cooling section which cools the formed material are provided, and
 the formed material in a filament shape is cooled by using at least one of air cooling, a cooling roller, a gas tank, and a liquid tank.   
     
     
         54 . The method for producing fiber according to  claim 51 , wherein
 the method for producing fiber comprises: extruding the molten liquid into a filament shape to provide a formed material; and conveying and concurrently cooling the formed material, and   a ratio of a speed of the formed material conveyed (V2) to a speed of the molten liquid extruded (V1), V2/V1, is 1 or more and 50 or less.   
     
     
         55 . The method for producing fiber according to  claim 54 , wherein the speed of the formed material conveyed, V2, is 0.2 m/min or more and 200 m/min or less. 
     
     
         56 . A melt spinning apparatus wherein
 the melt spinning apparatus comprises:
 a supply port to which a material is supplied; 
 a heating section which melts the material supplied from the supply port, without application of any kneading force; and 
 a nozzle which is in direct communication with the heating section and discharges the material in a molten state, 
   a resin composition used as the material for melt spinning is a filament and has a melt viscosity of 250 Pas or less at 200° C. and a shear rate of 0.1 s −1 , and   the melt spinning apparatus is configured so that the filament is supplied from the supply port and concurrently the material in a molten state is discharged from the nozzle to be spun.   
     
     
         57 . The melt spinning apparatus according to  claim 56 , further comprising a gas flow spraying section which conveys the resin composition discharged from the nozzle by gas flow, and/or an electrode which electrically charges the resin composition discharged from the nozzle. 
     
     
         58 . The melt spinning apparatus according to  claim 56 , further comprising an apparatus for producing the filament, wherein
 the apparatus for producing the filament comprises:
 an extruding section which extrudes a resin composition having a melt viscosity of 250 Pas or less at 200° C. and a shear rate of 0.1 s −1  into a filament shape to provide a formed material; and 
 a conveying section which receives the formed material extruded and conveys the formed material to the next step, and 
   a distance between a discharge port for the resin composition and the conveying section is 50 mm or less, and the discharge port has a diameter of 1 mm or more and 50 mm or less.   
     
     
         59 . The melt spinning apparatus according to  claim 56 , wherein the apparatus for producing the filament further comprises a cooling section which cools the formed material conveyed from the conveying section, and
 the cooling section is composed of one or more of a cooling conveyor, a cooling roller, a gas tank, and a liquid tank.   
     
     
         60 . The melt spinning apparatus according to  claim 56 , wherein, in the apparatus for producing the filament, a ratio of a temperature of a molten liquid of the resin composition to a temperature in the conveying section or the cooling section, in terms of an absolute temperature, is 1.2 or more and 2.1 or less.