CPC C08J 9/0061 (2013.01) [C08J 5/18 (2013.01); C08J 9/228 (2013.01); C09J 123/06 (2013.01); C09J 123/12 (2013.01); C09J 201/00 (2013.01); C08J 2323/06 (2013.01); C08J 2323/12 (2013.01); C09J 2203/00 (2013.01)] | 6 Claims |
1. A polyolefin resin foam sheet having front and back surfaces which is made of a polyolefin resin foam comprising a polyolefin resin and a thermoplastic elastomer resin, wherein
the polyolefin resin foam sheet endothermic peaks measured by a differential scanning calorimeter (DSC) occur in a range of at least 120° C. or more and 143° C. or less and at 153° C. or more and 170° C. or less,
said thermoplastic elastomer resin is contained at a ratio of 40% by mass or more and 60% by mass or less based on 100% by mass of the resins constituting the polyolefin resin foam sheet,
said polyolefin resin is contained at a ratio of 60% by mass or less and 40% by mass or more based on 100% by mass of the resins constituting the polyolefin resin foam sheet,
together the thermoplastic elastomer resin and the polyolefin resin constitute 100% by mass of the resins constituting the polyolefin resin foam sheet,
a surface roughness Sa (arithmetic mean height) of both the front and the back surfaces is 16 μm or more and 80 μm or less, and a difference in surface roughness Sa between the front and the back surfaces is 20 μm or more and less than 50 μm based on the following formula:
(Difference in surface roughness Sa between the front and the back surfaces)=(Surface roughness Sa on the surface B)−(Surface roughness Sa on the surface A),
both the surface A and the surface B are sliced and stretched,
an average cell size in a machine direction (MD) corresponding to a resin extrusion direction or length direction on both the front and the back surfaces is 134 μm or more and 550 μm or less, and
a ratio of the average cell size in the MD direction on the surface B to the average cell size in the MD direction on the surface A is 1.2 or more and 1.35 or less based on the following formula:
(Ratio of the average cell size in the MD direction)=(Average cell size in the MD direction on the surface B)/(Average cell size in the MD direction on the surface A).
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