# US 4,391,966 A · Polymers from phenylterephthalic acid

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- Number: US 4,391,966 A
- Document ID: US4391966A
- Status: Granted
- Kind: A
- Application number: 06/286,559
- Filed: 1981-07-24
- Granted: 1983-07-05
- Earliest claimed: 1979-12-10
- Assignees: E. I. Du Pont de Nemours and Company
- Inventors: John F. Harris, Jr.
- Web page: https://patentgrep.com/patent/US4391966A

## CPC

- C08G 63/605: {the hydroxy and carboxylic groups being bound to aromatic rings}
- C07C 63/15: all carboxyl groups bound to carbon atoms of the six-membered aromatic ring
- C08G 63/19: Hydroxy compounds containing aromatic rings
- C08G: MACROMOLECULAR COMPOUNDS OBTAINED OTHERWISE THAN BY REACTIONS ONLY INVOLVING UNSATURATED CARBON-TO-CARBON BONDS
- C07C: ACYCLIC OR CARBOCYCLIC COMPOUNDS

## Abstract

Melt-spinnable, anisotropic melt-forming aromatic polyesters prepared from phenylterephthalic acid or mixtures thereof with terephthalic acid, one or more selected aromatic diols, and 4-hydroxybenzoic acid; and filaments of such polyesters, the tenacity of which filaments can be increased by heat treatment.

## Claims

### Claim 1

Fiber forming melt-spinnable polyester that is optically anisotropic in the melt and consists essentially of recurring units having the structural formulas ##STR7## or a combination of (a) and up to 50 mole percent of ##STR8## wherein R.sup.1 is 1,4-phenylene, 2,6-naphthylene, 4,4'-biphenylene, or a mixture of any thereof;
(2) (a) --O--R.sup.2 --O--
wherein R.sup.2 is 1,4-phenylene, monochloro-, monophenyl-, or monoalkyl-1,4-phenylene wherein alkyl contains 1 to 4 carbon atoms, 2,6-naphthylene, 1,4-naphthylene, 4,4'-biphenylene or a mixture of any thereof, or a combination of (a) and up to 20 mole percent of ##STR9## and (3) based on the total moles of (1) and (3), 25 to 80 mole percent of ##STR10## the recurring diacid units (1) and recurring dioxy units (2) being present in substantially equimolar amounts.

### Claim 2 (depends on 1)

The polyester of claim 1 consisting essentially of recurring units having the structural formulas ##STR11## wherein R.sup.2 is 1,4-phenylene, monochloro-, monophenyl-, or monoalkyl-1,4-phenylene wherein alkyl contains 1 to 4 carbon atoms, 2,6-naphthylene, 1,4-naphthylene, 4,4'-biphenylene or mixtures thereof.

### Claim 3 (depends on 2)

The polyester of claim 2 wherein R.sup.2 is 1,4-phenylene.

### Claim 4 (depends on 1)

The polyester of claim 1 wherein R.sup.1 is 1,4-phenylene.

### Claim 5 (depends on 4)

The polyester of claim 4 wherein R.sup.2 is 1,4-phenylene.

### Claim 6 (depends on 1)

The polyester of claim 1 consisting essentially of units having the structural formulas ##STR12##

### Claim 7 (depends on 1)

The polyester of claim 1 wherein 30 to 70 mole percent of recurring unit (3) is present.

### Claim 8 (depends on 6)

The polyester of claim 6 wherein 30 to 70 mole percent of recurring unit (3) is present.

### Claim 9 (depends on 1)

Filament of the polyester of claim 1.