IMPROVED OXYGEN BARRIER OF 1,4-BUTANEDIOL CONTAINING POLYMERS

Abstract

In a first aspect, the invention relates to a polymer composition comprising (i) a polyester; and (ii) an oxidizable organic polymer consisting of a branched or unbranched alkyl chain, which comprises at least one oxidizable C═C double bond. A second aspect of the invention relates to the use of the polymer composition according to the first aspect for the preparation of a polymer article. In a third aspect, the invention relates to a polymer article comprising the polymer composition according to the first aspect. In a fourth aspect, the invention relates to a method for preparing a polymer composition having oxygen consumption activity.

Claims

1. A polymer composition comprising i) a polyester, which is a copolymer based on 1,4-butanediol and at least one organic dicarboxylic acid; ii) an oxidizable organic polymer consisting of a branched or unbranched alkyl chain, which comprises at least one oxidizable C═C double bond, which is poly(1,4-butadiene).

2. The polymer composition of claim 1, wherein the polyester according to (i) is polyester based on 1,4-butanediol and terephthalic acid.

3. The polymer composition of claim 1, which further comprises: iii) at least one iron containing catalyst.

4. The polymer composition of claim 1, wherein (i), (ii) and optionally (iii) are present in the polymer composition in form of a blend.

5. The polymer composition of claim 1, which does not contain a further compound capable of oxygen scavenging.

6. The polymer composition of claim 1, containing the oxidizable organic polymer according to (ii) in a weight based ratio to the polyester according to (i) in the range of from 0.1:100 to 10:100.

7. The polymer composition of claim 3, containing the at least one iron containing catalyst according to (iii) in a weight based ratio to the polyester according to (i) in the range of from 0.0001:100 to 5:100.

8. The polymer composition of claim 1 comprising: (i) a polyester, which comprises at least PBT; (ii) an oxidizable organic polymer, which is poly(1,4-butadiene); (iii) optionally at least one iron containing catalyst, which comprises one or more Fe.sup.3+ containing salts selected from the group consisting of Fe(III)stearate, Fe(III)pyrophosphate, Fe(III)citrate, Fe(III)acetylacetonate and mixtures of two or more of these Fe(III)salts; (iv) optionally one or more additive(s).

9. The polymer composition of claim 1 having an oxygen consumption of at least 5 mbar per gram polymer composition, determined according to Reference Example 2.

10. (canceled)

11. A polymer article comprising the polymer composition according to claim 1.

12. A method for preparing a polymer composition having oxygen consumption activity, comprising: a) providing a polyester (i), which is a copolymer based on 1,4-butanediol and at least one organic dicarboxylic acid, an oxidizable organic polymer consisting of a branched or unbranched alkyl chain, which comprises at least one oxidizable C═C double bond, which is poly(1,4-butadiene) (ii), optionally an iron containing catalyst (iii), and optionally one or more additive(s) (iv); b) mixing (i), (ii), optionally (iii) and optionally (iv) provided according to (a) to obtain a mixture of (i), (ii), optionally (iii), and optionally (iv); c) optionally drying the mixture obtained in (b), optionally at a temperature in a range of from 50 to 100° C. to remove water, thereby obtaining a dried mixture; d) compounding the mixture obtained in (b) and/or the dried mixture obtained in (c), thereby obtaining a polymer composition in compounded form comprising (i), (ii), optionally (iii), and optionally (iv).

13. (canceled)

14. The polymer composition of claim 3 wherein the iron containing catalyst is an Fe.sup.3+ containing salt, an Fe.sup.2+ containing salt, or a mixture of Fe.sup.3+ and Fe.sup.2+ containing salts.

15. The polymer composition of claim 3 wherein the iron containing catalyst is selected from the group consisting of Fe(III)stearate, Fe(III)pyrophosphate, Fe(III)citrate, Fe(III)acetylacetonate, and mixtures of two or more of these Fe(III)salts.

16. The polymer composition of claim 15 wherein the iron containing catalyst comprises Fe(III) pyrophosphate in a range of 95 to 100 weight % of the iron containing catalyst.

17. The polymer article according to claim 11 selected from the group consisting of a packaging article, a sealing article, and a wrapping article.

Description

EXAMPLES

[0079] TABLE-US-00001 Chemicals Name Details Supplier Fe(III)pyrophosphate Fe.sub.4(P.sub.2O.sub.7).sub.3 Sigma Aldrich Fe(III)stearate C.sub.54H.sub.105FeO.sub.6 Sigma Aldrich Fe(III)citrate C.sub.6H.sub.5FeO.sub.7 Sigma Aldrich Fe(III)acac (Fe(III)acetylacetonate) C.sub.15H.sub.21FeO.sub.6 Sigma Aldrich polybutylene terephthalate (PBT) VN = 160 cm.sup.3/dl BASF SE Poly(1,4-butadiene) Mn = 5000 g/mol Sigma Aldrich

Reference Example 1: Determination of Viscosity Number

[0080] Viscosity number (VN) was determined according to DIN EN ISO 1628-5 (October 2012).

Reference Example 2: Oxygen Consumption Testing

[0081] A predetermined amount (5 g) of a compound granulate as indicated in Table 1 was loaded in a 20 mL vial, which was closed by crimping a lid onto the vial. After crimping, the air composition inside the vial resembled that of the surrounding air and the pressure inside the vial was determined by using a manometer. The pressure decrease was determined by measuring the pressure inside the crimped vial as function of time. In Table 1 an overview of the maximum decrease of the pressure inside the closed vessel is presented, expressed as maximum pressure decrease in mbar per gram of compound.

Example 1: Preparation of Compound Granulate E1

[0082] A compound granulate was prepared as follows: PBT (19.58 g) was combined with poly(1,4-butadiene) (0.4 g) and Fe(III) stearate (0.024 g) in a glass container and dried overnight at 80° C. under vacuum to reduce the water content in the PBT. After drying of the physical mixture, the mixture was added to a DSM-IV mini-extruder, which was pre-heated to 260° C. The mixture was molten in the mini-extruder and was compounded for 3 minutes at a temperature of 260° C. After this time, the molten compound from PBT was expelled from the extruder as a strand. This strand was then granulated by hand to form the final product (compound granulate of inventive example 1 - E1). Table 1 shows the educts and amounts used as well as the result of the oxygen consumption testing done in accordance with Reference Example 2.

Examples 2 to 7

[0083] The inventive compound granulates of examples 2 to 7 (E2 - E7) were prepared using the same method as described above in example 1 for E1, an overview of the educts and amounts used as well as the results of the oxygen consumption testing done in accordance with Reference Example 2 are shown in Table 1.

Comparative Examples 1 to 2

[0084] The compound granulates of comparative examples 1 to 2 (C1-C2) examples were prepared using the same method as described above in example 1 for E1, an overview of the compounds and amounts used as well as the results of the oxygen consumption testing done in accordance with Reference Example 2 are shown in Table 1.

TABLE-US-00002 Composition of compounds of inventive and comparative examples and results of oxygen consumption testing Example Compound composition Max. pressure decrease (mbar) per gram* PBT (weight-%) oxidizable organic polymer oxidizable organic polymer content (weight-%) Catalyst Catalyst content (weight-%) E1 97.88 Poly(1,4-butadiene) 2 Fe(III)stearate 0.12 6.8 E2 97.88 Poly(1,4-butadiene) 2 Fe(III)pyrophosphate 0.12 12.4 E3 97.88 Poly(1,4-butadiene) 2 Fe(III)citrate 0.12 6.4 E4 97.88 Poly(1,4-butadiene) 2 Fe(III)acac 0.12 13.2 E5 98.95 Poly(1,4-butadiene) 1 Fe(III)acac 0.05 13.6 E6 99.38 Poly(1,4-butadiene) 0.5 Fe(III)acac 0.12 10.4 E7 98.00 Poly(1,4-butadiene) 2 none 0 13.6 C1 99.88 - 0 Fe(III)stearate 0.12 0 C2 97.88 Poly(1,2-butadiene) 2 Fe(III)stearate 0.12 1.4 C3 100 None 0 None 0 0 * measurement error ± 0.6 mbar per gram

[0085] It could be seen that using poly(1,4-butadiene) as oxidizable organic polymer in a compound with PBT significantly improved the oxygen consumption, i.e. the pressure decrease in mbar per gram of the respective compound (E7) was strongly improved compared to a compound of PBT and only catalyst (C1) and also compared to pure PBT (C3). Using an iron containing catalyst, especially Fe(III)acetylacetonate (E4, E5) or Fe(III)pyrophosphate (E2), as catalyst also improved the oxygen consumption compared to a blend of PBT and only catalyst (C1) as well as compared to pure PBT (C3). Using poly(1,2-butadiene) instead of poly(1,4-butadiene) showed a remarkably worse oxygen consumption even if an iron containing catalyst (Fe(III)stearate, C2) was used as catalyst.

Cited Literature

[0086] EP 1 889 704 A1 [0087] EP 2 886 602 A1 [0088] GB 2 435 394 A [0089] Mahan et al., J. Appl. Polym. Sci. 2013, 4273-4283 [0090] US 8,029,842 B2 [0091] US 10,207,853 B2 [0092] US 2007/0138436 A1 [0093] Wang et al., Macromol. Chem. Phys. 2019, 220, 1900294