Catalyst for producing polyesters and polyester resin composition

Abstract

Polyester composition produced without antimony compound as a polycondensation catalyst including, 30 ppm or less antimony, 0.5-50 ppm titanium, and 0.1-100 ppm phosphorus, the number density of titanium-containing particles having an equivalent circular diameter of 1 μm or more being less than 100/0.02 mg; and a composition as above, containing 0.1-5 wt % organic polymer particles which have an average particle diameter of 0.05-3 μm and contain 0.01% or less of coarse particles which have a diameter at least twice the average particle diameter. Polyester catalyst including a reaction product between at least one of Ti(OR) 4 and Ti(OH) m (OR) 4-m , wherein Rs may be the same or different and each represents a C 2 -C 10 organic group, and m represents an integer of 1-4, and a ligand including nitrogen, sulfur, and/or oxygen as a donor atom, and capable of coordinating with two or more sites.

1 . A catalyst for producing polyesters, comprising a reaction product between at least one compound selected from the group consisting of the compounds represented by general formulae 7 and 8 below and a ligand comprising at least one type of atom selected from the group consisting of a nitrogen atom, a sulfur atom, and an oxygen atom as a donor atom, and being capable of coordinating with two or more sites:
   Ti(OR) 4    (Formula 7)
     Ti(OH) m (OR) 4-m    (Formula 8),
   
       wherein Rs may be the same or different and each represents a C 2 -C 10  organic group, and m represents an integer of 1 to 4. 
     
     
         2 . The catalyst for producing polyesters according to  claim 1 , wherein the organic group R is an alkyl group. 
     
     
         3 . The catalyst for producing polyesters according to  claim 1 , wherein the compound represented by general formula 7 or 8 is a tetraalkoxytitanium compound or a titanium chelate compound. 
     
     
         4 . The catalyst for producing polyesters according to  claim 1 , wherein the ligand is at least one compound selected from the group consisting of metal-free phthalocyanine, indanthrone, anthraquinone, and methine. 
     
     
         5 . A polyester resin composition produced in the presence of the catalyst for producing polyesters according to  claim 1 . 
     
     
         6 . A polyester film comprising the polyester resin composition according to  claim 5 . 
     
     
         7 . A laminated polyester film comprising a plurality of layers, at least one of which comprises the polyester resin composition according to  claim 5 . 
     
     
         8 . A magnetic recording medium, comprising the laminated polyester film according to  claim 7 .