Polyethylene-based resin multilayer foam sheet, interleaf sheet for glass plates, and method for manufacturing polyethylene-based resin multilayer foam sheet

A polyethylene-based resin multilayer foam sheet comprising a foam layer, and a resin layer provided on each of both sides of the foam layer,

• the resin layer having a multilayer structure comprising a surface layer that is located on an outermost surface side of the multilayer foam sheet, and an intermediate layer that is positioned between the surface layer and the foam layer,
• the foam layer including a polyethylene-based resin PE2,
• wherein
• the intermediate layer is composed of an antistatic resin composition containing a polyethylene-based resin PE3 and a polymeric antistatic agent,
• the surface layer is composed of a mixed resin containing a polyethylene-based resin PE4 and a polystyrene-based resin,
• the mixed resin is substantially free of a polymeric antistatic agent,
• a content of the polystyrene-based resin in the mixed resin is 3% by weight or more and 35% by weight or less, and
• a surface resistivity of the polyethylene-based resin multilayer foam sheet is 1×1013Ω or less.

A method for producing a polyethylene-based resin multilayer foam sheet having a surface resistivity of 1×1013Ω or less and having a multilayer structure in which a first surface layer, a first intermediate layer, a foam layer, a second intermediate layer and a second surface layer are laminated in this order, said method comprising the steps of:

• providing a foamable melt M2 for forming the foam layer that contains a polyethylene-based resin PE2 and a physical blowing agent, a melt M3 for forming the first and second intermediate layers that is configured of an antistatic resin composition containing a polyethylene-based resin PE3 and a polymeric antistatic agent, and a melt M4 for forming the first and second surface layers that is configured of a mixed resin containing a polyethylene-based resin PE4 and a polystyrene-based resin and being free of a polymeric antistatic agent,
• laminating the melts M4, M3, M2, M3 and M4 in this order within a die to form a laminated mass, and
• coextruding the laminated mass from the die to expand the foamable melt M2,
• wherein the polystyrene-based resin is contained in the mixed resin composition in an amount of 3% by weight or more and 35% by weight or less based on the weight of the mixed resin composition.