Flame-retardant poly lactic acid-containing film or sheet, and method for manufacturing thereof

A method for manufacturing a film or sheet, comprising:

• forming the film from a resin composition by melt film formation,
• the resin composition comprising:
• a poly lactic acid (A);
• an acidic functional group-modified olefinic polymer (B) including an acidic functional group and having an acid value of 10 to 70 mg KOH/g and a weight average molecular weight of 10,000 to 80,000;
• a tetrafluoroethylene polymer (C);
• and
• an aromatic cyclic phosphazene-containing flame retardant (D) including a compound of Formula (I′),
• the aromatic cyclic phosphazene-containing flame retardant (D) being included in an amount of 10 to 70 parts by weight based on 100 parts by weight of the poly lactic acid (A),
• wherein each of X1 and X2 is independently an alkyl group having 1 to 4 carbon atoms;
• each of m1 and m2 is independently an integer of 0 to 4, and n is an integer of 3 to 6;
• the resin composition during the melt film formation having a temperature between a temperature 15° C. higher than a crystallization temperature (Tc) of the resin composition in a temperature drop process and a temperature 5° C. lower than a melting temperature (Tm) in a temperature rise process or
• the melt film formed resin composition being cooled and solidified after a crystallization accelerating step of keeping the resin composition between a temperature 25° C. lower than a crystallization temperature (Tc) of the resin composition in a temperature drop process and a temperature 10° C. higher than the crystallization temperature (Tc).