Cover film

Abstract

Disclosed is a cover film which is used in combination with a carrier tape and comprises at least a base layer, an intermediate layer, a releasing layer and a heat seal layer that is capable of being heat sealed to the carrier tape. The intermediate layer contains, as a main component, a linear low density polyethylene that is polymerized using a metallocene catalyst and has a tensile modulus of 200 MPa or less. The releasing layer contains a conductive material and also contains, as a main component, a hydrogenated resin of an aromatic vinyl-conjugated diene copolymer having an aromatic vinyl group content of 15-35% by mass. This cover film is small in variation in peel strength when the cover film is released, and is thus capable of suppressing troubles during the releasing in a mounting process.

1 . A cover film comprising at least a substrate layer, an intermediate layer, a peel layer, and a heat seal layer capable of heat-sealing a carrier tape; wherein
 the intermediate layer comprises, as a main component, a linear low-density polyethylene with a tensile elasticity of 200 MPa or less, polymerized using a metallocene catalyst; and   the peel layer comprises a conductive material, and comprises, as a main component, a hydrogenated resin of an aromatic vinyl-conjugated diene copolymer with an aromatic vinyl group content of 15 to 35 mass %.   
     
     
         2 . The cover film of  claim 1 , wherein the hydrogenated resin of an aromatic vinyl-conjugated diene copolymer of peel layer is a resin with a density of 0.890 to 0.920×103 (kg/m3) and a weight-average molecular weight of 50,000 to 150,000. 
     
     
         3 . The cover film of  claim 1 , wherein the heat seal layer comprises an acrylic resin as a main component. 
     
     
         4 . The cover film of  claim 1 , wherein the conductive material is conductive microparticles comprising microparticles that are acicular, spherical, or a combination thereof. 
     
     
         5 . The cover film of  claim 1 , wherein the conductive material is a carbon nanomaterial. 
     
     
         6 . The cover film of  claim 1 , wherein the conductive material is acicular microparticles of antimony-doped tin oxide. 
     
     
         7 . The cover film of  claim 1 , wherein the heat seal layer further comprises a conductive material. 
     
     
         8 . The cover film of  claim 1 , wherein peeling occurs between the peel layer and the heat seal layer when peeling away the cover film heat-sealed to the carrier tape. 
     
     
         9 . The cover film of  claim 1 , wherein the surface resistivity of the peel layer and/or the heat seal layer is 1×104 to 1×1012Ω. 
     
     
         10 . An electronic component package using the cover film of  claim 1  as a lid material for carrier tape having a thermoplastic resin as a main component.