TECHNOLOGY FOCUS - POLYMERS - Preferred Composition: The polyester is aromatic dibasic acid or its ester-forming derivative. The content of cyclic carbodiimide compound contained with respect to polyester is 0.05-5 %mass. Preferred Definitions:    R2,R6=H.    EXAMPLE - Liquid mixture of 1.1 mol nitric acid and 800 ml acetic acid was slowly dripped into 1 mol carvacrol and 1.6 L acetic acid in reactor and then extracted with ethyl acetate. The obtained organic layer was washed with water, dried using magnesium sulfate, concentrated and purified using column chromatography, to obtain 50 g o-nitro carvacrol. 0.05 mol 1,2-Dibromo ethane, 0.3 mol potassium carbonate and 200 ml N,N-dimethylformamide were added to o-nitro carvacrol, reacted and solvent was distilled off under reduced pressure. The obtained solid substance was dissolved in 200 ml dichloromethane, and liquid separation was performed with 100 ml water. The obtained organic layer was spin-dried with 5 g magnesium sulfate, and solvent was distilled off under reduced pressure, to obtain intermediate product (A). 0.1 mol intermediate product (A), 1 g palladium/carbon and 200 ml ethanol/dichloromethane were added into a reactor. Hydrogen gas was supplied, and reacted at 25 degrees C. the solvent was distilled off, to obtain intermediate product (B). 0.025 mol Intermediate product (B), 0.2 mol imidazole, 0.2 mol carbon disulfide and 150 ml acetonitrile were added into a reactor maintained under nitrogen atmosphere, reacted at 80 degrees C for 15 hours, concentrated and purified, to obtain intermediate product (C). 0.025 mol Intermediate product (C), 0.052 mol sodium hydroxide having concentration of 30%, 0.0019 mol benzyl chloride triethylammonium, 170 ml chloroform and 5.8 ml methanol were added into a reactor, 0.103 mol hypochlorous acid aqueous solution was dripped and reacted for 1 hour. Liquid-separation was carried out. Obtained chloroform solution was spin-dried with magnesium sulfate, concentrated and washed using hexane, to obtain 9,16-dimethyl-6,19-bis(propan-2-yl)-11,14-dioxa-2,4-diazatricyclo(13.4.0.05,10)nonadeca-1(15),2,3,5(10),6,8,16,18-octaene.