Foam body, polyolefin-based foam sheet, and complex

An uncrosslinked foam body comprising:

• 70% by mass or more and 90% by mass or less of a 4-methyl-1-pentene-based polymer including a constitutional unit derived from 4-methyl-1-pentene (A1) and a constitutional unit derived from an α-olefin having 2 to 3 carbon atoms (A2), and
• 5% by mass or more and 30% by mass or less of a foamable modified resin, wherein the foamable modified resin is at least one selected from the group consisting of thermoplastic polyamide-based resins, hydrogenated styrene-based elastomers, acrylic acid, methacrylic acid or maleic acid-modified thermoplastic polyamide-based resins and acrylic acid, methacrylic acid or maleic acid-modified hydrogenated styrene-based elastomers,
• wherein a maximum peak height (Rp) of at least one surface of the uncrosslinked foam body, which is measured according to JIS B0601:2001, is 67 μm or more and 190 μm or less, and
• wherein one or more temperatures showing a maximum value of loss tangent (tan δ), which is obtained by dynamic viscoelasticity measurement conducted under conditions of a temperature increase rate of 4° C./min, a frequency of 1.59 Hz, and a distortion of 0.1%, exist in at least a range of 10° C. or higher and 40° C. or lower, and the maximum value of the loss tangent is 0.8 or more and 3.0 or less,
• wherein the uncrosslinked foam body has a density of 0.10-0.80 g/cm3,
• wherein a total of the constitutional unit (A1) derived from the 4-methyl-1-pentene and the constitutional unit (A2) derived from the α-olefin having 2 to 3 carbon atoms is 100 mol %, a content of the constitutional unit (A1) is 72 mol % or more and 90 mol % or less and a content of the constitutional unit (A2) is 10 mol % or more and 28 mol % or less, and
• wherein when a Shore A hardness of at least one surface of the uncrosslinked foam body immediately after measurement, which is measured at 23° C. according to JIS K6253, is HS0, and a Shore A hardness 15 seconds after the measurement is HS1,
• ΔHS expressed by (HS0−HS1) is 30 or more and 60 or less, and
• HS0 is 54 or more and 68 or less.