Decorative sheet and decorative plate

A decorative sheet comprising a transparent resin layer, and a base material sheet, and optionally further comprising a synthetic-resin backer layer, and the transparent resin layer, the base material sheet, and the synthetic-resin backer layer being thermoplastic resin layers, wherein

• (1) at least one of the thermoplastic resin layers contains a metal phosphinate-based flame retardant, wherein the metal phosphinate-based flame retardant comprises metal phosphinates and/or dimetal phosphinates,
• the metal phosphinates comprising compounds represented by the following formula (1);
• the dimetal phosphinates comprising compounds represented by the following formula (2):
• wherein in formulas (1) and (2), R1, R2, R3, and R4 are each independently selected from the group consisting of C1-C6 alkyl groups, C6-C12 aryl groups, and C7-C20 arylalkyl groups, R5 is selected from the group consisting of C1-C10 alkylene groups, C6-C10 arylene groups, C7-C20 alkylarylene groups, and C7-C20 arylalkylene groups, M is at least one metal selected from the group consisting of magnesium and aluminum;
• m is 2 or 3;
• n is 1 or 3;
• and x is 1 or 2;
• (2) the transparent resin layer contains 5 parts by mass or more and 30 parts by mass or less of the metal phosphinate-based flame retardant, based on the amount of at least one member selected from the group consisting of polyolefin-based resins and polyester-based resins in the transparent resin layer being defined as 100 parts by mass, the base material sheet contain at least one resin selected from the group consisting of polyolefin-based resins and polyester-based resins;
• and
• (3) the synthetic-resin backer layer contains at least one resin selected from the group consisting of polypropylene, ethylene-vinyl alcohol copolymers, polymethylene, polymethyl pentene, polyethylene terephthalate, highly heat-resistant polyalkylene terephthalate, polybutylene terephthalate, polyethylene naphthalate, polyethylene naphthalate-isophthalate copolymers, polycarbonate, polyarylate, polyimide, polystyrene, polyamide, and ABS, and the synthetic-resin backer layer optionally contains the metal phosphinate-based flame retardant.