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US 6,281,325 B1Granted
Preparation of poly(trimethylene terephthalate)
AssigneeE. I. Du Pont de Nemours and Company
InventorsJoseph Varapadavil Kurian, Yuanfeng Liang
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AssigneeE. I. Du Pont de Nemours and Company
InventorsJoseph Varapadavil Kurian, Yuanfeng Liang
Estimating the term…
In one embodiment, the invention is a process for the preparation of poly(trimethylene terephthalate) comprising (a) contacting terephthalic acid with 1,3-propanediol in the presence of an organic tin catalyst to form a bis(3-hydroxypropyl)terephthalate monomer; and (b) polymerizing said monomer in the presence of organic titanate polycondensation catalyst to obtain the poly(trimethylene terephthalate). In another embodiment, the invention is a process for the preparation of poly(trimethylene terephthalate) containing less than 1.6 mol % of DPG said process comprising contacting terephthalic acid with a 1.6 to 1 to 2:1 molar amount of 1,3-propanediol in the presence of 20 to 120 ppm (as tin), by weight of the poly(trimethylene terephthalate), of a organic tin catalyst, to form a bis(3-hydroxypropyl)terephthalate monomer and polymerizing said monomer to obtain the poly(trimethylene terephthalate). The invention is also directed to poly(trimethylene terephthalate) produced by the processes.
A process for the preparation of poly(trimethylene terephthalate) comprising (a) contacting terephthalic acid with 1,3-propanediol in the presence of an organic tin oxide catalyst to form a bis(3-hydroxypropyl)terephthalate monomer;
A process for the preparation of poly(trimethylene terephthalate) containing less than 1.6 mol % of DPG said process comprising contacting terephthalic acid with a 1.6:1 to 2:1 molar amount of 1,3-propanediol in the presence of 20 to 120 ppm (as tin), by weight of the poly(trimethylene terephthalate), of a organic tin oxide catalyst, to form a bis(3-hydroxypropyl)terephthalate monomer and polymerizing said monomer to obtain the poly(trimethylene terephthalate).
Dependencies are inferred from the claim text.