Antistatic laminated foam sheet and process for producing same
AssigneeJsp Corporation
InventorsTakashi Nishimoto, Ryohei Takeuchi
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Abstract
A laminated foam sheet obtained by a coextrusion lamination method and having a polyethylene foam layer, and an antistatic layer laminated on at least one side of the foam layer. The antistatic layer contains a polyethylene resin, an ionomer resin and a polyalkylene glycol and has such specific morphology that the polyethylene resin forms a continuous phase and the ionomer resin forms small dispersed phases dispersed in the continuous phase.
Claims11
An extruded laminated foam sheet comprising a foam layer containing a polyethylene-based resin (PE-1), and an antistatic layer laminated on at least one side of the foam layer,
- said antistatic layer having a basis weight of 1 to 20 g/m2 and containing a polyethylene-based resin (PE-2), an ionomer resin having an antistatic property and a polyalkylene glycol,
- wherein the ionomer resin is contained in the antistatic layer in an amount of 5 to 50% by weight based on the total weight of the polyethylene-based resin (PE-2) and the ionomer resin,
- wherein the polyethylene-based resin (PE-2) forms a continuous phase, and the ionomer resin forms dispersed phases dispersed in the continuous phase, and
- wherein, on a vertical cross-section of the antistatic layer, which is taken along the extrusion direction of the laminated foam sheet, a number-based median value S50 of cross-sectional areas of the dispersed phases is 1×102 to 5×105 nm2, and
- wherein a weight ratio of the polyalkylene glycol to the ionomer resin is 0.03 to 0.6.
A process for producing a laminated foam sheet having a polyethylene-based resin foam layer and a polyethylene-based resin antistatic layer laminated on at least one side of the foam layer, comprising the steps of:
- providing a first melt containing a polyethylene-based resin (PE-1) and a physical blowing agent,
- providing a second melt containing a polyethylene-based resin (PE-2), an ionomer resin having an antistatic property, a polyalkylene glycol and a volatile plasticizer, and
- coextruding the first and second melts to form the laminated foam sheet in which the polyethylene-based resin foam layer and the polyethylene-based resin antistatic layer are formed from the first and second melts, respectively,
- wherein the ionomer resin is present in the second melt in an amount of 5 to 50% by weight based on the total weight of the polyethylene-based resin (PE-2) and the ionomer resin, wherein a weight ratio of the polyalkylene glycol to the ionomer resin is 0.03 to 0.6,
- wherein the antistatic layer having a basis weight of 1 to 20 g/m2,
- wherein the polyethylene-based resin (PE-2) forms a continuous phase, and the ionomer resin forms dispersed phases dispersed in the continuous phase, and
- wherein, on a vertical cross-section of the antistatic layer, which is taken along the extrusion direction of the laminated foam sheet, a number-based median value S50 of cross-sectional areas of the dispersed phases is 1×102 to 5×105 nm2.
Dependencies are inferred from the claim text.