# US 11,305,519 B2 · Antistatic laminated foam sheet and process for producing same > Agents: this data is available as JSON from the patentgrep API and MCP server — see https://patentgrep.com/llms.txt - Number: US 11,305,519 B2 - Document ID: US11305519B2 - Status: Granted - Kind: B2 - Application number: 16/887,465 - Filed: 2020-05-29 - Published: 2020-12-24 - Granted: 2022-04-19 - Earliest claimed: 2019-06-24 - Assignees: Jsp Corporation - Applicants: Jsp Corporation - Inventors: Takashi Nishimoto; Ryohei Takeuchi - Web page: https://patentgrep.com/patent/US11305519B2 ## CPC - B32B 5/18: characterised by features of a layer {of} foamed material - B32B 27/065: {of foam} - B32B 27/22: using plasticisers - B32B 27/30: comprising vinyl {(co)polymers; comprising acrylic (co)polymers} - B32B 27/32: comprising polyolefins {(comprising vinyl (co)polymers or acrylic (co)polymers B32B27/30)} - C08J 9/12: by a physical blowing agent - B32B 2250/02: 2 layers - B32B 2250/03: 3 layers - B32B 2250/24: All layers being polymeric - B32B 2250/246: All polymers belonging to those covered by groups B32B27/32 and B32B27/30 - B32B 2266/025: Polyolefin - B32B 2270/00: Resin or rubber layer containing a blend of at least two different polymers - B32B 2307/21: Anti-static - B32B 2323/04: Polyethylene - B32B 2553/02: Shock absorbing - C08J 2201/03: Extrusion of the foamable blend - C08J 2323/06: Polyethene - B32B: LAYERED PRODUCTS, i.e. PRODUCTS BUILT-UP OF STRATA OF FLAT OR NON-FLAT, e.g. CELLULAR OR HONEYCOMB, FORM - C08J: WORKING-UP; GENERAL PROCESSES OF COMPOUNDING; AFTER-TREATMENT NOT COVERED BY SUBCLASSES C08B, C08C, C08F, C08G or C08H (working, e.g. shaping, of plastics B29) ## 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. ## Claims ### Claim 1 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. ### Claim 2 (depends on 1) The extruded laminated foam sheet according to claim 1, wherein, on the vertical cross-section of the antistatic layer, an aspect ratio LM50/LT50 of a number-based median value LM50 of diameters in the extrusion direction of the dispersed phases to a number-based median value LT50 of diameters in the thickness direction of the dispersed phases is 2 or more. ### Claim 3 (depends on 1) The extruded laminated foam sheet according to claim 1, wherein the polyalkylene glycol is present in the antistatic layer in an amount of 0.3 to 6% based on the weight of the antistatic layer. ### Claim 4 (depends on 1) The extruded laminated foam sheet according to claim 1, wherein a difference (Tmp−Tmi) between a melting point Tmp of the polyethylene-based resin (PE-2) and a melting point Tmi of the ionomer resin is 5 to 30° C. ### Claim 5 (depends on 1) The extruded laminated foam sheet according to claim 1, wherein the antistatic layer has a surface resistivity of 1×1013Ω or less. ### Claim 6 (depends on 1) The extruded laminated foam sheet according to claim 1, wherein the extruded laminated foam sheet has a thickness of 0.05 to 2 mm. ### Claim 7 (depends on 1) The extruded laminated foam sheet according to claim 1, wherein the extruded laminated foam sheet has an apparent density of 15 to 200 kg/m3. ### Claim 8 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. ### Claim 9 (depends on 8) The process according to claim 8, wherein the volatile plasticizer is present in the second melt in an amount of 1 to 60 parts by weight per 100 parts by weight of the total weight of the polyethylene-based resin (PE-2) and the ionomer resin and wherein a weight ratio of the volatile plasticizer to polyalkylene glycol is 5 to 100. ### Claim 10 (depends on 8) The process according to claim 8, wherein the volatile plasticizer is at least one selected from the group consisting of saturated hydrocarbons having 3 to 5 carbon atoms, dialkyl ethers in which each alkyl has 1 to 3 carbon atoms, and alcohols. ### Claim 11 (depends on 8) The process according to claim 8, wherein the volatile plasticizer is n-butane, isobutane or a mixture thereof.