Method for producing resin strand

Abstract

The present invention can eliminate a breakage of strands on the way to increase yield, significantly suppress formation of adhered consecutive pellets, and obtain pellets having a low moisture content by a method for producing a resin strand comprising melt-kneading a resin composition in an extruder, extruding a strand-shaped molten resin onto a conveyor, and cooling the resin strand with cooling water, wherein the conveyed strand-shaped molten resin is brought into initial contact with the cooling water at a position downstream ranging from 20% to 70% of the total length of the conveying part of the conveyor.

1 . A method for producing a resin strand comprising the steps of: 
 melt-kneading a resin composition in an extruder;    extruding a strand-shaped molten resin onto a conveyor; and    cooling the resin strand with cooling water;    wherein the conveyed strand-shaped molten resin is brought into initial contact with the cooling water at a position downstream ranging from 20% to 70% of the total length of the conveying part of the conveyor.    
   
   
       2 . The method for producing a resin strand according to  claim 1 , wherein the cooling water is sprayed water.  
   
   
       3 . The method for producing a resin strand according to  claim 1 , wherein the cooling water has a temperature of 5° C. or above and 50° C. or below.  
   
   
       4 . The method for producing a resin strand according to  claim 1 , wherein the length from the position at which the conveyed strand-shaped molten resin is brought into initial contact with the cooling water to an extruder die hole is 1.5 m or more and 4.5 m or less.  
   
   
       5 . The method for producing a resin strand according to  claim 1 , wherein a discharge per unit area of the opening of an extruder die hole is from 80 kg/cm 2  to 200 kg/cm 2 .  
   
   
       6 . The method for producing a resin strand according to  claim 1 , wherein the strand just before cutting has a temperature ranging from 100° C. to 150° C.  
   
   
       7 . A pellet obtained by cutting a strand produced by the method according to  claim 1 .  
   
   
       8 . The pellet according to  claim 7 , wherein the percentage of adhered consecutive pellets is less than 2% by mass of the total pellet.  
   
   
       9 . The method for producing a resin strand according to  claim 1 , wherein the resin composition comprises one or more resins selected from the group of polyarylene sulfide, polyetheretherketone, polysulfone, polyethersulfone, polyamide, polyester, liquid crystal polymers, polyarylate, polycarbonate, polyphenylene ether, and polyetherimide.  
   
   
       10 . The method for producing a resin strand according to  claim 1 , wherein the resin composition is a mixture comprising two or more resins selected from the group of polyarylene sulfide, polyetheretherketone, polyamide, polyester, liquid crystal polymers, polyphenylene ether, and polyetherimide, the mixture comprising both a crystalline resin and an amorphous resin; and the crystalline resin forming a continuous phase and the amorphous resin forming a disperse phase.  
   
   
       11 . The method for producing a resin strand according to  claim 10 , wherein the resin composition comprises at least polyamide and polyphenylene ether.  
   
   
       12 . The method for producing a resin strand according to  claim 11 , wherein the resin composition comprises polyamide, polyphenylene ether, and one or more compounds selected from the group of maleic acid, citric acid, fumaric acid, and an anhydride thereof in powder or granule form.  
   
   
       13 . The method for producing a resin strand according to  claim 12 , wherein the polyphenylene ether is a powdery polyphenylene ether comprising 60% by mass or more of fine particles not passing a 145 mesh (106 μm opening) woven wire cloth (according to JIS G3555-1983) made of stainless steel wire having a diameter of 65 μm.  
   
   
       14 . The method for producing a resin strand according to  claim 12 , wherein the one or more compounds selected from the group of maleic acid, citric acid, fumaric acid, and an anhydride thereof in powder or granule form comprise 80% by mass or more of particles passing a 6 mesh (3.1 mm opening) woven wire cloth (according to JIS G3555-1983) made of stainless steel wire having a diameter of 1.4 mm.  
   
   
       15 . The method for producing a resin strand according to  claim 12 , comprising the steps of: 
 forming a preblend of 100 parts by mass of a powdery polyphenylene ether and 50 to 200 parts by mass of one or more compounds selected from the group of maleic acid, citric acid, fumaric acid, and an anhydride thereof in powder or granule form; and then    feeding the preblend to an extruder through a feeder different from a feeder used for feeding the remaining polyphenylene ether.    
   
   
       16 . The method for producing a resin strand according to  claim 15 , wherein the amount of the powdery polyphenylene ether incorporated into the preblend is less than 5% by mass of the amount of all the polyphenylene ether used in the resin composition.  
   
   
       17 . The method for producing a resin strand according to  claim 12 , wherein the amount of the one or more compounds selected from the group of maleic acid, citric acid, fumaric acid, and an anhydride thereof in powder or granule form is from 0.01 to 1 part by mass based on 100 parts by mass of all the polyphenylene ether.  
   
   
       18 . The method for producing a resin strand according to  claim 15 , further comprising a peroxide in the preblend.  
   
   
       19 . The method for producing a resin strand according to  claim 1 , wherein the resin composition comprises 5 to 50% by mass of an inorganic filler based on 100% by mass of the resin composition.  
   
   
       20 . The method for producing a resin strand according to  claim 19 , wherein the inorganic filler is one or more selected from the group of glass fiber, glass flake, talc, wollastonite, mica, titanium dioxide, alumina, silica, zinc oxide, and zinc sulfide.  
   
   
       21 . The method for producing a resin strand according to  claim 1 , further comprising an electrically conductive carbon filler.  
   
   
       22 . The method for producing a resin strand according to  claim 21 , wherein the electrically conductive carbon filler is at least one selected from the group of electrically conductive carbon black, carbon fibril, and graphite.  
   
   
       23 . A preblend comprising 100 parts by mass of a powdery polyphenylene ether and 50-200 parts by mass of one or more compounds selected from the group of maleic acid, citric acid, fumaric acid, and an anhydride thereof in powder or granule form.  
   
   
       24 . The preblend according to  claim 23 , wherein the one or more compounds selected from the group of maleic acid, citric acid, fumaric acid, and an anhydride thereof in powder or granule form are powdery or granular compounds comprising 80% by mass or more of particles passing a 6 mesh (3.1 mm opening) woven wire cloth (according to JIS G3555-1983) made of stainless steel wire having a diameter of 1.4 mm.  
   
   
       25 . The preblend according to  claim 23 , wherein the powdery polyphenylene ether is a powdery polyphenylene ether comprising 80% by mass or more of fine particles not passing a 145 mesh (106 μm opening) woven wire cloth (according to JIS G3555-1983) made of stainless steel wire having a diameter of 65 μm.