Co-extruded sheet

A co-extruded sheet containing a polycarbonate resin, comprising:

• a core layer formed from a foam resin;
• a first skin layer formed from a non-foaming resin and laminated to one major surface of the core layer;
• and
• a second skin layer laminated to another major surface of the core layer,
• wherein:
• the polycarbonate resin contained in the first and second skin layers has a melt volume-flow rate 1 to 5 times a melt volume-flow rate of the polycarbonate resin contained in the core layer,
• the co-extruded sheet has a density of 0.4 to 0.9 g/cm3,
• the co-extruded sheet has a thickness of 1 to 5 mm and satisfies the following expression (1):
• 0.1
• ≤
• (
• t
• ⁢
• 1
• +
• t
• ⁢
• 2
• )
• /
• T
• ≤
• 0.5
• ,
• (
• 1
• )
• in expression (1), t1 indicates a thickness of the first skin layer, t2 indicates a thickness of the second skin layer, and T indicates a thickness of the co-extruded sheet;
• and,
• when the co-extruded sheet is heated for 30 minutes in a heated atmosphere at 250° C., an average thickness t5 of the co-extruded sheet after the heating is not larger than 1.5 times an average thickness t4 of the co-extruded sheet before the heating.

A co-extruded sheet containing a polycarbonate resin, comprising:

• a core layer formed from a foam resin;
• a first skin layer formed from a non-foaming resin and laminated to one major surface of the core layer;
• and
• a second skin layer laminated to another major surface of the core layer,
• wherein:
• the polycarbonate resin contained in the first and second skin layers bas a melt volume-flow rate 1 to 5 times a melt volume-flow rate of the polycarbonate resin contained in the core layer,
• the co-extruded sheet has a density of 0.4 to 0.9 g/cm3,
• the co-extruded sheet has a thickness of 1 to 5 mm and satisfy the following expression (1):
• 0.1
• ≤
• (
• t
• ⁢
• 1
• +
• t
• ⁢
• 2
• )
• /
• T
• ≤
• 0.5
• ,
• (
• 1
• )
• in expression (1), t1 indicates a thickness of the first skin layer, t2 indicates a thickness of the second skin layer, and T indicates a thickness of the co-extruded sheet;
• and
• the core layer has an expansion ratio of 1.6 to 3.3.