Process of producing polytrimethylene terephthalate (PTT)

US6277947A · kind A · utility

Assignee

• SHELL OIL COMPNY · US

Inventors

• Donald R. Kelsey · Brookshire, US
• Robert Lawrence Blackbourn · Houston, US
• Robert Stephen Tomaskovic · Richmond, US
• Hans Reitz · Rosbach, DE
• Eckhard Seidel · Frankfurt, DE
• Fritz Wilhelm · Karben, DE

Key dates

• Filing date: Apr 21, 2000
• Grant date: Aug 21, 2001
• Expiry date: Apr 21, 2020

Classification

• Technology area (CPC C): Chemistry; Metallurgy
• CPC primary: C08G63/183
• WIPO field: Macromolecular chemistry, polymers
• WIPO sector: Chemistry

Abstract

Process of producing polytrimethylene terephthalate (PTT) by esterification of terephthalic acid (TPA) with trimethylene glycol (TMG) in the presence of a catalytic titanium compound, precondensation and polycondensation. The esterification is effected in at least two stages, where in the first stage a molar ratio of TMG to TPA of 1.15 to 2.5, a content of titanium of 0 to 40 ppm, a temperature of 240 to 275.degree. C., and a pressure of 1 to 3.5 bar are used. In the at least one subsequent stage a content of titanium is adjusted which is higher than in the initial stage by 35 to 110 ppm.