Process for the preparation of copolyesters based on 2,2,4,4-tetramethyl-1,3-cyclobutanediol and 1,4-cyclohexanedimethanol
First Claim
1. A process for the preparation of a copolyester, comprising:
- reacting a diester composition comprising dimethyl terephthalate with a first diol component comprising 2,2,4,4-tetramethyl-1,3-cyclobutanediol and a second diol component comprising 1,4-cyclohexanedimethanol, said reaction comprising(i) reacting said first diol component comprising about 100 mole percent of said 2,2,4,4-tetramethyl-1,3-cyclobutanediol, based on the total moles of 2,2,4,4-tetramethyl-1,3-cyclobutanediol in said first and second diol components, and about 30 to about 80 mole percent of said 1,4-cyclohexanedimethanol, based on the total moles of 1,4-cyclohexanedimethanol in said first and second diol components, with said diester composition to form a polyester oligomer at a conversion of said 2,2,4,4-tetramethyl-1,3-cyclobutanediol of at least 50 mole percent, based on the total moles of said 2,2,4,4-tetramethyl-1,3-cyclobutanediol in said first and second diol components;
(ii) reacting said second diol component comprising about 20 to about 70 mole percent of said 1,4-cyclohexanedimethanol based on the total moles of 1,4-cyclohexanedimethanol in said first and second diol components, with said polyester oligomer of step (i) to form a modified polyester oligomer; and
(iii) heating said modified polyester oligomer to form a thermoplastic, random copolyester having an inherent viscosity of about 0.4 dL/g to about 1.0 dL/g;
wherein the molar ratio of all diols in said first and second diol components to all diesters in said diester composition is about 1.1 to about 1.5.
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Abstract
Disclosed is a process for the preparation of high molecular weight, thermoplastic copolyesters by reacting a diester composition comprising a dialkyl ester of terephthalic acid with a diol composition comprising a first diol component comprising 2,2,4,4-tetramethyl-1,3-cyclobutanediol and a second diol component comprising 1,4-cyclohexanedimethanol. The diester composition can be reacted with the first diol component to produce a polyester oligomer that can be reacted further with the second diol component to produce a modified polyester oligomer. The modified polyester oligomer can then be heated to form a copolyester. The process reduces the precipitation of poly(1,4-cyclohexylene dimethylene) terephthalate in the reaction mixture.
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Citations
15 Claims
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1. A process for the preparation of a copolyester, comprising:
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reacting a diester composition comprising dimethyl terephthalate with a first diol component comprising 2,2,4,4-tetramethyl-1,3-cyclobutanediol and a second diol component comprising 1,4-cyclohexanedimethanol, said reaction comprising (i) reacting said first diol component comprising about 100 mole percent of said 2,2,4,4-tetramethyl-1,3-cyclobutanediol, based on the total moles of 2,2,4,4-tetramethyl-1,3-cyclobutanediol in said first and second diol components, and about 30 to about 80 mole percent of said 1,4-cyclohexanedimethanol, based on the total moles of 1,4-cyclohexanedimethanol in said first and second diol components, with said diester composition to form a polyester oligomer at a conversion of said 2,2,4,4-tetramethyl-1,3-cyclobutanediol of at least 50 mole percent, based on the total moles of said 2,2,4,4-tetramethyl-1,3-cyclobutanediol in said first and second diol components; (ii) reacting said second diol component comprising about 20 to about 70 mole percent of said 1,4-cyclohexanedimethanol based on the total moles of 1,4-cyclohexanedimethanol in said first and second diol components, with said polyester oligomer of step (i) to form a modified polyester oligomer; and (iii) heating said modified polyester oligomer to form a thermoplastic, random copolyester having an inherent viscosity of about 0.4 dL/g to about 1.0 dL/g; wherein the molar ratio of all diols in said first and second diol components to all diesters in said diester composition is about 1.1 to about 1.5. - View Dependent Claims (2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14, 15)
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Specification