Additive for thermpolastic resins and flame retardant resin composition

A flame retardant polyester resin composition comprising:

• (A) a thermoplastic polyester,
• (B) 2 to 50% by weight of a heterocyclic compound or a salt thereof based on said polyester (A), where said heterocyclic compound is at least one member selected from the group consisting of a compound of the formula (I) ##STR13## wherein R.sup.1, R.sup.2 and R.sup.3 may be the same or different and each is hydrogen atom, amino group, an aryl group or a hydroxyalkyl group having 1 to 3 carbon atoms;
• a compound of the formula (II):
• ##STR14## wherein R.sup.4, R.sup.5 and R.sup.6 may be the same or different and each is hydrogen atom, amino group, an aryl group or a hydroxyalkyl group having 1 to 3 carbon atoms;
• and a compound of the formula (II):
• ##STR15## wherein R.sup.7, R.sup.8 and R.sup.9 may be the same or different and each is hydrogen atom, amino group, hydroxyl group, mercapto group, an alkylamino group having 1 to 10 carbon atom, anilino group, morpholino group, hydrazino group, benzylamino group, pyridylamino group, thenylamino group or a hydroxyalkyl group having 1 to 3 carbon atoms,
• (C) 0.1 to 50% by weight of a compound having at least two functional groups based on the component (B), and
• (D) 0 to 50% by weight of a phosphorus-based flame retarder based on said polyester (A).

A flame retardant polyester resin composition comprising:

• (A) a thermoplastic polyester,
• (B) 2 to 50% by weight of a heterocyclic compound or a salt thereof based on said polyester (A), where said heterocyclic compound is at least one member selected from the group consisting of a compound of the formula (I):
• ##STR18## wherein R.sup.1, R.sup.2 and R.sup.3 may be the same or different and each is hydrogen atom, amino group, an aryl group or a hydroxyalkyl group having 1 to 3 carbon atoms;
• a compound of the formula (II);
• and ##STR19## wherein R.sup.4, R.sup.5 and R.sup.6 may be the same or different and each is hydrogen atom, amino group, an aryl group or a hydroxyalkyl group having 1 to 3 carbon atoms;
• and a compound of the formula (III):
• ##STR20## wherein R.sup.7, R.sup.8 and R.sup.9 may be the same or different and each is hydrogen atom, amino group, hydroxyl group, mercapto group, an alkylamino group having 1 to 10 carbon atoms, anilino group, morpholino group, hydrazino group, benzylamino group, pyridylamino group, thenylamino group or a hydroxyalkyl group having 1 to 3 carbon atoms,
• (C) 0.1 to 50% by weight of at least one member selected from the group consisting of a diepoxy compound, a carboxylic acid dianhydride, a diisocyanate compound and a polycarbodiimide based on said component (B), and
• (D) 0 to 50% by weight of a condensed phosphoric acid ester of the formula (V):
• ##STR21## wherein R.sup.11 to R.sup.22 are independently hydrogen atom or an alkyl group having 1 to 4 carbon atoms, Y is a single bond, an alkylene group having 1 to 3 carbon atoms, --S--, --SO.sub.2 --, --O--, --CO-- or --N.dbd.N--, and k is 0 or 1.

A process for preparing a flame retardant polyester resin composition comprising the steps of mixing a thermoplastic polyester with a compound having at least two functional groups, and mixing the resultant with a heterocyclic compound or a salt thereof and optionally other ingredients, wherein said composition comprises:

• (A) said thermoplastic polyester,
• (B) 2 to 50% by weight of said heterocyclic compound or said salt based on said polyester (A), where said heterocyclic compound is at least one member selected from the group consisting of a compound of the formula (I):
• ##STR22## wherein R.sup.1, R.sup.2 and R.sup.3 may be the same or different and each is hydrogen atom, amino group, an aryl group or a hydroxyalkyl group having 1 to 3 carbon atoms;
• a compound of the formula (II):
• ##STR23## wherein R.sup.4, R.sup.5 and R.sup.6 may be the same or different and each is hydrogen atom, amino group, an aryl group or a hydroxyalkyl group having 1 to 3 carbon atoms;
• and a compound of the formula (III):
• ##STR24## wherein R.sup.7, R.sup.8 and R.sup.9 may be the same or different and each is hydrogen atom, amino group, hydroxyl group, mercapto group, an alkylamino group having 1 to 10 carbon atoms, anilino group, morpholino group, hydrazino group, benzylamino group, pyridylamino group, thenylamino group or a hydroxyalkyl group having 1 to 3 carbon atoms,
• (C) 0.1 to 50% by weight of said compound having at least two functional groups based on said component (B), and
• (D) 0 to 50% by weight of a phosphorus-based flame retarder based on said polyester (A).