Patent ID: 6716521
Filing Date: 2004-04-06
Classification: C08L,G11B,Y10T

Abstract:
A polyester composition comprising:a polyester resin matrix; and 0.005 to 5% by weight of inorganic particles; wherein the polyester resin matrix contains phosphorous, alkali metal ions and alkaline earth metal ions and wherein the inorganic particles comprise as a major component a compound oxide of silicon dioxide and aluminum oxide, and additionally contain ions of elements in group Ia of the periodic table wherein on a molar basis, 80 to 100% of the ions are potassium ions, such that the ratio on a molar basis of Al/Si is 0.1&lE;Al/Si&lE;0.4, and the ratio on a molar basis of the ions of elements in group Ia of the periodic table to Al is 0.8&lE;(group Ia ions)/Al&lE;1.2, and wherein the polyester resin matrix satisfies the following equation: 0.3&lE;((Ma/2)+Mb)/P&lE;3.0 wherein Ma is the concentration (mol/kg) of alkali metal ions, Mb is the concentration (mol/kg) of alkaline earth metal ions and P is the concentration (mol/kg) of phosphorus, in the polyester matrix.