Aliphatic-aromatic polyester having elevated whiteness index

Patent metadata

Field	Value
Publication number	US-11560450-B2
Application number	US-201816617640-A
Country	US
Kind code	B2
Filing date	May 22, 2018
Priority date	May 31, 2017
Publication date	Jan 24, 2023
Grant date	Jan 24, 2023

Abstract

The present invention relates to an aliphatic-aromatic polyester having a whiteness index according to ASTM E 313-73 of at least 25, to a process for preparation thereof and to the use of the aliphatic-aromatic polyester for production of polyester fibers (PF). The present invention further relates to the polyester fibers (PF) comprising the aliphatic-aromatic polyester.

First claim

The invention claimed is:

1. An aliphatic-aromatic polyester obtainable by condensation at least of components (A), (B), (C) and optionally (D):
(A) 40 to 70 mol %, based on components (A) and (B), of adipic acid and/or at least one adipic acid derivative,
(B) 30 to 60 mol %, based on components (A) and (B), of at least one aromatic 1,ω-dicarboxylic acid and/or at least one 1,ω-dicarboxylic acid derivative,
(C) 98 to 102 mol %, based on components (A) and (B), of at least one aliphatic 1,ω-diol, and
(D) 0% to 5% by weight, based on the total weight of components (A) to (C), of at least one chain extender,

wherein the aliphatic-aromatic polyester has a whiteness index according to ASTM E 313-73 of at least 25, and wherein the condensation comprises the four stages i) to iv):
i) a continuous esterification,
ii) a precondensation,
iii) a postcondensation, and
iv) a polyaddition reaction,

wherein 0.03% to 0.04% by weight of a phosphorus compound is added to the precondensation product obtained in the second stage after process step ii) and before and/or during process step iii), based on the total weight of the precondensation product.

2. An aliphatic-aromatic polyester according to claim 1 , wherein the aliphatic-aromatic polyester has a whiteness index according to ASTM E 313-73 of 25 to 40.

3. An aliphatic-aromatic polyester according to claim 1 , wherein the aliphatic-aromatic polyester has an acid number measured according to DIN EN ISO 2114:2002-06 in the range from 1.1 to 1.4 mg KOH/g.

4. An aliphatic-aromatic polyester according to claim 1 , wherein the aliphatic-aromatic polyester has a viscosity number according to DIN 53728 in the range from 100 to 300 cm 3 /g.

5. An aliphatic-aromatic polyester according to claim 1 , wherein the aliphatic-aromatic polyester is obtainable by condensation at least of components (A), (B), (C) and optionally (D):
(A) 45 to 65 mol %, based on components (A) and (B), of adipic acid and/or at least one adipic acid derivative,
(B) 35 to 55 mol %, based on components (A) and (B), of at least one aromatic 1,ω-dicarboxylic acid and/or at least one 1,w-dicarboxylic acid derivative,
(C) 99 to 101 mol %, based on components (A) and (B), of at least one aliphatic 1,ω-diol, and
(D) 0.01% to 5% by weight, based on the total weight of components (A) to (C), of at least one chain extender.

6. An aliphatic-aromatic polyester according to claim 1 , wherein component (B) is terephthalic acid and/or a terephthalic acid derivative.

7. An aliphatic-aromatic polyester according to claim 1 , wherein component (C) is propane-1,3-diol and/or butane-1,4-diol.

8. An aliphatic-aromatic polyester according to claim 1 , wherein component (D) is hexamethylene diisocyanate.

9. An aliphatic-aromatic polyester according to a claim 1 , wherein the glass transition temperature (T G ) of the aliphatic-aromatic polyester is in the range from −50 to 0° C.

10. A process for preparing an aliphatic-aromatic polyester according to claim 1 , wherein
i) in a first stage a mixture comprising components (A), (B) and (C) is continuously esterified in the presence of a catalyst to obtain an esterification product,
ii) in a second stage the esterification product obtained in the first stage is continuously precondensed up to a viscosity number according to DIN 53728 of 20 to 70 cm 3 /g to obtain a precondensation product,
iii) in a third stage the precondensation product obtained in the second stage is continuously postcondensed up to a viscosity number according to DIN 53728 of 60 to 170 cm 3 /g to obtain a postcondensation product, and
iv) in a fourth stage the postcondensation product obtained in the third stage is continuously reacted in a polyaddition reaction with the at least one chain extender (D) up to a viscosity number according to DIN 53728 of 100 to 300 cm 3 /g to obtain the aliphatic-aromatic polyester,

where 0.03% to 0.04% by weight of a phosphorus compound is added to the precondensation product obtained in the second stage after process step ii) and before and/or during process step iii), based on the total weight of the precondensation product.

11. The process according to claim 10 , wherein stages i) and ii) are conducted in the presence of a titanium catalyst.

12. The process according to claim 10 , wherein the phosphorus compound is phosphorous acid.

13. Polyester fibers (PF) each comprising, based on the total weight of the polyester fibers (PF),
80% to 99% by weight of at least one terephthalate polyester,
1% to 20% by weight of at least one aliphatic-aromatic polyester according to claims 1 to 9 , and
0% to 5% by weight of at least one additive (E),
wherein the polyester fibers (PF) have a whiteness index according to CIE 15.3 of at least 65.

14. Polyester fibers (PF) according to claim 13 , wherein the at least one terephthalate polyester is polyethylene terephthalate (PET) and/or polybutylene terephthalate (PBT).

15. An aliphatic-aromatic polyester obtainable by a process according to claim 10 .

Assignees

• Basf Se

Inventors

• Scheuermann Klaus
• Loos Robert
• Garbe Andreas
• Müller Kevin

Classifications

• D01F6/84

  from copolyesters · CPC title

• D01F6/92

  of polyesters · CPC title

• C08G63/183 Primary

  Terephthalic acids · CPC title

• D10B2331/04

  polyesters, e.g. polyethylene terephthalate [PET] · CPC title

• C08K5/29

  Compounds containing {one or more} carbon-to-nitrogen double bonds · CPC title