Patent ID: 9724894
Date: 2017-08-08
CPC Classifications: B29C,B32B,B41M,H01F,Y10T

Claim:
1. A process for preparing a multilayered polymer print film comprising the steps of: providing a first polymer resin for feedstock of a first layer; providing a second polymer resin for feedstock of a second layer; blending feedstock for a core layer, wherein said feedstock for said core layer comprising ferromagnetic particles and a third polymer resin, wherein said ferromagnetic particles are about 15% to about 70% by weight of said feedstock for said core layer, wherein the inclusion of said ferromagnetic particles into said feedstock of said core layer slows cooling of the core layer compared to a layer extruded from a polymer resin feedstock without said ferromagnetic particles; suppressing a cooling rate of said first layer by adjusting an amount of a first filler added to said first polymer resin and blending a mixture of said first filler and said first polymer resin to prepare feedstock for said first layer so that said first layer and said core layer are cooled at substantially same rate after extrusion, wherein a total amount of said first filler used is about 20% to about 30% by weight of feedstock for said first layer; suppressing a cooling rate of said second layer by adjusting an amount of a second filler added to said second polymer resin and blending a mixture of said second filler and said second polymer resin to prepare feedstock for said second layer so that said second layer and said core layer are cooled at substantially same rate after extrusion, wherein a total amount of said second filler used is about 20% to about 30% by weight of feedstock for said second layer; transferring said blended feedstock for said first layer, said core layer, and said second layer into three different slots of a co-extruder; heating said co-extruder to a temperature sufficient to melt said blended feedstock for said core layer, said first and second layers; coextruding said molten blended feedstock from said three different slots through a single die head of said co-extruder to provide a multilayered film having said first layer, said core layer, and said second layer, wherein said core layer is disposed in between said first and second layers, wherein said outer surfaces of said first and second layers are absent or substantially absent of ferromagnetic particles and suitable to accept printing; and cooling said multilayered film on a chill roller, wherein said first layer, said core layer, and said second layer have substantially the same cooling rate.