Fiber adhesive

Abstract

Tacky polymeric fibers having a nontacky core and a tacky outer shell.

1 . A tacky polymeric fiber having a nontacky core and a tacky outer shell. 
     
     
         2 . The tacky polymeric fiber according to  claim 1 , wherein the core comprises a polymer (referred to below for short as core polymer) which at 21° C. has a breaking strength of between 5 and 60 Mpa and a breaking extension of between 2% and 1500% (by ISO 527 tensile test). 
     
     
         3 . The tacky polymeric fiber according to  claim 1 , wherein the core polymer is a thermoplastic or is a thermoplastic which has been modified with an elastomer (thermoplastic elastomer). 
     
     
         4 . The tacky polymeric fiber according to  claim 1 , wherein the core polymer is a styrene copolymer. 
     
     
         5 . The tacky polymeric fiber according to  claim 1 , wherein the core is composed of more than 90% by weight of the core polymer and may further comprise additives which may be stabilizers, fillers, carbon nanotubes, pigments, dyes. 
     
     
         6 . The tacky polymeric fiber according to  claim 1 , wherein the outer shell is composed of a permanently tacky adhesive, of a pressure-sensitive adhesive. 
     
     
         7 . The tacky polymeric fiber according to  claim 6 , wherein the adhesive is a permanently tacky hotmelt adhesive. 
     
     
         8 . The tacky polymeric fiber according to  claim 1 , wherein the adhesive, or hotmelt adhesive, at 21° C. has a peel strength of at least 1 N/2.5 cm. 
     
     
         9 . The tacky polymeric fiber according to  claim 1 , wherein the hotmelt adhesive comprises as binder a polymer (referred to below as adhesive polymer) which is obtainable by free-radical polymerization of ethylenically unsaturated compounds. 
     
     
         10 . The tacky polymeric fiber according to  claim 9 , wherein the adhesive polymer is a UV-crosslinkable polymer. 
     
     
         11 . The tacky polymeric fiber according to  claim 1 , wherein the adhesive is composed of more than 40% by weight of the adhesive polymer and if appropriate may further comprise additives, which may be tackifying resins, plasticizers, UV blockers, antioxidants, dyes or fillers. 
     
     
         12 . The tacky polymeric fiber according to  claim 1 , wherein the polymeric fiber has a diameter of 8 μm to 500 μm. 
     
     
         13 . The tacky polymeric fiber according to  claim 12 , wherein the core has a diameter of 5 μm to 497 μm. 
     
     
         14 . The tacky polymeric fiber according to  claim 13 , wherein the outer shell has a layer thickness of 3 μm to 100 μm. 
     
     
         15 . A process for producing the tacky polymeric fiber according to  claim 1 , which comprises coextruding the core material and the material for the outer shell. 
     
     
         16 . The process according to  claim 15 , wherein the core material is heated to temperatures between 150 and 300° C. and the material of the outer shell is heated to temperatures between 80 and 200° C. and the coextrusion takes place at these temperatures. 
     
     
         17 . The process according to  claim 16 , wherein the polymeric fiber obtained is additionally drawn immediately after coextrusion, the length increase (degree of drawing) being preferably 10% to 300%. 
     
     
         18 . The method of using the polymeric fiber according to  claim 1  for producing permeable layers, which may be permeable nonwovens, membranes, textile sheet structures. 
     
     
         19 . The method of using the polymeric fiber according to  claim 17  for binding, immobilizing or strengthening small piece goods. 
     
     
         20 . The method of using the polymeric fiber according to  claim 17  for producing gas-permeable sheet structures with a large adhesion area, for producing dust filters or particle filters for example. 
     
     
         21 . The method of using the polymeric fiber according to  claim 17  for producing elastic sheet structures which at application temperature are tacky and/or detachable, for transporting and/or sorting goods. 
     
     
         22 . The method of using the polymeric fiber according to  claim 17  for producing permeable sheet structures with a large adhesion area for removing dispersed or emulsified particles from liquid or gaseous media.