Aromatic polyester of 2,6 and/or 2,7 naphthalene dicarboxylic acid

Claim 2

A linear aromatic polyester consisting essentially of, in the polymer molecule, about 50 to 100 mole % of a first repeating unit being represented by the formula ##SPC4## in which R 1 and R 2 are the same or different and represent an alkyl group of 1-3 carbons, n is an integer of 1-6, X is a halogen atom and m is 0, 1 or 2; and from 0 to about 50 mole % of a second repeating unit being represented by the formula ##SPC5## in which p is an integer of 1-6; with an intrinsic viscosity of 0.3 or more when measured at 35°C. by

Claim 3

A polyester according to claim 1 in which the second repeating unit is

Claim 4

A polyester according to claim 2 in which the first repeating unit is at least 70 mole % and the second repeating unit is not more than 30 mole %.

Claim 5

A polyester according to claim 1, in which, in the first repeating unit,

Claim 6

A process for the production of a linear aromatic polyester which comprises: reacting at a temperature of from 150° to 240°C. naphthalenedicarboxylic acid of the formula ##SPC6## or its ester-forming derivative with (1) 4,4'-bis(hydroxyalkoxyphenyl)-2,2-alkane being represented by the formula ##SPC7## in which R 1 and R 2 are the same or different and an alkyl group of 1-3 carbons, n is an integer of 1-6, X is a halogen atom and m is 0, 1 or 2, or its ester-forming derivative or (2) said 4,4'-bis(hydroxyalkoxyphenyl)-2,2-alkane or its ester-forming derivative and at least one compound selected from the group consisting of (a) aromatic carboxylic acids different from said naphthalenedicarboxylic acid or their ester-forming derivatives and (b) glycols different from said 4,4'-bis(hydroxyalkoxyphenyl)-2,2-alkane or their ester-forming derivatives, to form an ester; followed by polymerizing the ester so obtained at a temperature of 240° to 300°C.; with the proviso that the mole amount of the above glycol component be from 1 to 3.8 moles for every mole of the above acid component.

Claim 7

A process for the production of a linear aromatic polyester which comprises: reacting at a temperature of from 150° to 240°C. naphthalenedicarboxylic acid of the formula ##SPC6## or its ester-forming derivative with (1) 4,4'-bis(hydroxyalkoxyphenyl)-2,2-alkane being represented by the formula ##SPC7## in which R 1 and R 2 are the same or different and an alkyl group of 1-3 carbons, n is an integer of 1-6, X is a halogen atom and m is 0, 1 or 2, or its ester-forming derivative or (2) said 4,4'-bis(hydroxyalkoxyphenyl)-2,2-alkane or its ester-forming derivative and at least one compound selected from the group consisting of (a) aromatic carboxylic acids different from said naphthalenedicarboxylic acid or their ester-forming derivatives and (b) glycols different from said 4,4'-bis(hydroxyalkoxyphenyl)-2,2-alkane or their ester-forming derivatives, to form an ester; followed by polymerizing the ester so obtained at a temperature of 240° to 300°C.; with the proviso that the mole amount of the above glycol component be from 1 to 3.8 moles for every mole of the above acid component.