Abstract: To make a thickness of a concavo-convex sheet as uniform as possible while ensuring the function of an air bubble sheet as a cushioning material. A synthetic resin air bubble sheet is provided in which a concavo-convex sheet (11) and a flat sheet (12) are joined and a plurality of air bubble portions (13) are formed that form sealed spaces between the concavo-convex sheet (11) and the flat sheet (12). Each of the air bubble portions (13) has a circular truncated cone shape whose diameter becomes smaller toward the top. Where A is the diameter of the part with the largest diameter, a height B from the flat sheet (12) is in the range of 35% to 40% of A, a diameter C of a flat top portion (11d), which is the part with the smallest diameter, is in the range of 50% to 80% of A, and a radius of curvature R of a top corner portion (11c) that is formed between the flat top portion (11d) and a side wall portion (11b) is in the range of 10% to 20% of A.

Abstract: A plastic sheet having a number of recessed and protruded parts useful as a protective sheet in moving and construction, and for cushion packaging and thermal insulation is disclosed. Also disclosed is a two-layered or three-layered double wall sheet, which is produced by adhering one or two flat plastic sheets on the above plastic sheet. The double wall sheet has high rigidity against bending and improved warps when compared with the conventional plastic bubble boards, and is useful as the material for various panels and packaging containers. The plastic sheet is produced by vacuum forming to form plural protruded, truncated cone-shaped parts and recessed, ring-shaped parts surrounding and continuing from the protruding parts. The double wall sheet is produced by adhering a back sheet and/or liner sheet to the plastic sheet.

Abstract: A plastic sheet having a number of recessed and protruded parts useful as a protective sheet in moving and construction, and for cushion packaging and thermal insulation is disclosed. Also disclosed is a two-layered or three-layered double wall sheet, which is produced by adhering one or two flat plastic sheets on the above plastic sheet. The double wall sheet has high rigidity against bending and improved warps when compared with the conventional plastic bubble boards, and is useful as the material for various panels and packaging containers. The plastic sheet is produced by vacuum forming to form plural protruded, truncated cone-shaped parts and recessed, ring-shaped parts surrounding and continuing from the protruding parts. The double wall sheet is produced by adhering a back sheet and/or liner sheet to the plastic sheet.