High-temperature self-crosslinking-based flame-retardant anti-dripping copolyester, and preparation method therefor and application thereof

A copolyester, comprising structural units represented by [I], [II], [III] and [IV]:

• structural unit [I]
• wherein R1 represents an arylene group;
• structural unit [II]
• wherein R2 represents an alkylene group;
• structural unit [III], which has a structure selected from formulae [A]-[R],
• in the formulae [A]-[R], R3 and R4 are the same or different and are any one of carbonyl, O atom or,
• wherein a is an integer of 2 to 12;
• X1 and X2 are the same or different and are any one of H atom, hydroxyl, methyl, ethyl, cyano, methoxy, phenylacetylenyl or phenyl;
• Y1 is O atom or S atom;
• structural unit [IV], which has a structure selected from formulae [A1]-[F1],
• in the formulae [A1]-[F1], R5 and R6 are the same or different and are any one of carbonyl, O atom or
• wherein a is an integer of 2 to 12;
• R7 is C1-C12 alkyl, aryl or benzyl;
• R8 is C1-C8 alkylene or arylene;
• Y2 is O atom or S atom;
• Y3 is any one of O atom, S atom, imino (HN<), methylimino (CH3N<) or ethylimino (C2H5N<);
• M is any one of metal atoms Li, Na, K, Mg, Ca, Mn, Co, Ni, Ba, Fe, Cs or Zn;
• n is an integer of 1 to 3;
• wherein the number of structural units of [III] is 1-99% of the number of structural units of [I];
• when [III] is a structural unit represented by formulae A, B, C, D, E, O, G, P, L, N, M, Q or R, the number of structural units of [IV] is 0.1-99% of the number of structural units of [I];
• when [III] is a structural unit represented by formulae F, H, I, J or K, the number of structural units of [IV] is 0-99% of the number of structural units of [I].