METHOD FOR PRODUCING A MULTI-LAYER RESIN FILM AND METHOD FOR PRODUCING A METAL SHEET COATED WITH RESIN

摘要

A method for producing a multi-layer resin film, wherein a plurality of molten resins being different in the melt viscosity are laminated on the surface of a film containing at least one resin containing a coloring component without formation of irregularities; and a method for producing a metal sheet having a resin coating film which comprises laminating said film on a metal sheet. The above method for producing a multi-layer resin film compr i ses keeping the temperatures of an extruder, a manifold and a dye portion adjacent to the manifold for the pass of a resin having a higher melt viscosity at a I eve l higher than those of the temperatures of an extruder, a manifold and a dye portion adjacent to the manifold for the pass of a resin having a lower melt viscosity, to thereby reduce the difference in the melt viscosities of adjacent resin layers to 3000 poise or less at a shear rate of 20 to 500 sec- 1 , and laminating respective molten resins while adjusting a resin containing a coloring component so as to have 0.5g ‰¦ Tm ‰¦1.0g, wherein Tm represents a melt strength, and a thickness of one half of the total thickness or more or having Tm ‰§ 1.0g and a thickness of one th i rd of the total thickness or more, to thereby form a multi-layer film.