Polyolefin yarns and method for manufacturing

Abstract

The invention relates to a multifilament yarn having a tenacity of at least 30 cN/dtex, and comprising a plurality of spun ultrahigh molecular weight polyolefin filaments characterized in that the titer of any one of said spun filaments is at least 10 dtex.

1 . A multifilament yarn having a tenacity of at least 30 cN/dtex, and comprising a plurality of spun ultrahigh molecular weight polyethylene filaments characterized in that the titer of any one of said spun filaments is at least 10 dtex. 
     
     
         2 . The yarn of  claim 1  having a tenacity of at least 35 cN/dtex, preferably at least 40 cN/dtex, more preferably at least 45 cN/dtex. 
     
     
         3 . The yarn of  claim 1  having a filament titer of at least 12, preferably at least 14, more preferably at least 16 dtex. 
     
     
         4 . The yarn of  claim 1  having a titer of at least 50 dtex, preferably at least 100 dtex, most preferably at least 400 dtex. 
     
     
         5 . The yarn of  claim 1  wherein the filaments comprise a hard filler having a Moh's hardness of at least 2.5. 
     
     
         6 . The yarn of  claim 1  further containing filaments manufactured from natural materials and preferably having discontinuous lengths said natural material being chosen from the group of materials consisting of cellulose, cotton, hemp, wool, silk, jute, sisal, cocoas and linen; with cotton being the preferred natural material. A fabric comprising the yarns of  claim 1  and a glove comprising the fabric. 
     
     
         7 . A product chosen from the group of products consisting of fishing lines and fishing nets, ground nets, cargo nets and curtains, kite lines, dental floss, tennis racquet strings, canvas, nonwoven cloths and other types of fabrics, webbings, battery separators, capacitors, pressure vessels, hoses, (offshore) umbilical cables, electrical, optical fiber, and signal cables, automotive equipment, power transmission belts, building construction materials, cut and stab resistant and incision resistant articles, protective gloves, composite sports equipment such as skis, helmets, kayaks, canoes, bicycles and boat hulls and spars, speaker cones, high performance electrical insulation, radomes, sails and geotextiles, said product comprising the yarns of  claim 1 . 
     
     
         8 . The spun UHMWPE monofilament of the multifilament yarn of  claim 1 , wherein the monofilament is a gel-spun monofilament with a tenacity of at least 30 cN/dtex and a titer of at least 10 dtex. 
     
     
         9 . The monofilament of  claim 7  wherein the monofilament has a strength of at least 4.0 N, preferably at least 4.5 N, more preferably of at least 5.0 N. 
     
     
         10 . A method for manufacturing  claim 1 , comprising in the following order the steps of:
 a. Providing a solution of ultrahigh molecular weight polyethylene, in a suitable solvent, preferably decaline;   b. Forcing said solution through a die containing a plurality of apertures wherein the apertures issue said solution at a first speed to form a plurality of filaments containing said solution; each aperture having an exit with an exit diameter D ap   exit ; each of said filaments having a diameter D fil  as measured at the exit of said capillary;   c. Immersing said solution-containing-filaments into a cooling bath;   preferably cooling water bath; and taking-up said immersed filaments onto a take-up roll rotating at a second speed; and   d. Taking-out said filaments from the bath to form spun filaments, at least partially extracting the solvent and drawing said spun filaments in at least one drawing step before; during and/or after said extraction;   
       wherein step b) is operated at a draw-down (DD op ), defined as the ratio between the second speed and the first speed, of between 20% and 90% of a resonance draw-down DD res ; wherein DD res  is the ratio between the second speed and the first speed whereat D fil  fluctuates per minute with a percentage of at least 25%, between a maximum value D fil   max  and a minimum value D fil   min ; 
       wherein said percentage is calculated with Formula 1 
       
         
           
             
               
                 
                   
                     100 
                     × 
                     
                       
                         
                           D 
                           fil 
                           max 
                         
                         - 
                         
                           D 
                           fil 
                           min 
                         
                       
                       
                         D 
                         fil 
                         avg 
                       
                     
                   
                 
                 
                   
                     Formula 
                      
                     
                         
                     
                      
                     1 
                   
                 
               
             
           
         
       
       wherein D fil   avg  is the average value of D fil  calculated from a number of at least 10 measurements recorded during a minute.