Process for preparing copolyesters of terephthalic acid, ethylene glycol, and 1,4-cyclohexanedimethanol
This invention relates to a three-step process for preparing copolyesters exhibiting a neutral hue, high clarity and increased brightness. The process involves reacting terephthalic acid, ethylene glycol, and 1,4-cyclohexanedimethanol in a feed mole ratio of total glycols to dicarboxylic acid of 1.7...
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Zusammenfassung: | This invention relates to a three-step process for preparing copolyesters exhibiting a neutral hue, high clarity and increased brightness. The process involves reacting terephthalic acid, ethylene glycol, and 1,4-cyclohexanedimethanol in a feed mole ratio of total glycols to dicarboxylic acid of 1.7:1 to 6.0:1, at a temperature of 240 degree C to 280 degree C, and a pressure of 15 psig (200 kPa) to 80 psig (650 kPa) to form an esterification product; adding a polycondensation catalyst and a toner; and polycondensing the product at a temperature of 260 degree C to 290 degree C and at reduced pressure to form a high molecular weight copolyester. |
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