Oxygen Scavenging Composition for Plastic Material

Abstract

The invention relates to the use of an additive as oxygen scavenger in a plastic material, wherein (a) the plastic material is a polyester, a polyolefin, a polyolefin copolymer or a polystyrene, and the additive (b) is a light stabilizer and optionally a transition metal compound.

Claims

1. A plastic material comprising an additive as an oxygen scavenger, and optionally, a transition metal catalyst, wherein: (a) the plastic material is a polyester, a polyolefin, a polyolefin copolymer or a polystyrene, and the additive is (b): (b) a compound of formula (1), ##STR00019## wherein Ra is a group of formula (A), ##STR00020## wherein Rb is selected from the group consisting of hydrogen, C.sub.1-C.sub.6 alkyl, C.sub.1-C.sub.6 alkoxy and —CO—C.sub.1-C.sub.4 alkyl; Rc is C.sub.7-C.sub.20 alkyl, C.sub.6-C.sub.10 aryl, C.sub.4-C.sub.10 heteroaryl, wherein the heteroatoms are N, O and/or S, (C.sub.2-C.sub.6)-alkenylen-(C.sub.6-C.sub.10) aryl, C.sub.1-C.sub.6-alkylen-C.sub.6-C.sub.10-aryl, the aryl and heteroaryl radicals optionally being substituted by hydroxyl, C.sub.1-C.sub.6-alkyl, C.sub.1-C.sub.6 alkoxyl, C.sub.6-C.sub.10 aryloxy, halogen, cyano, nitro, C.sub.6-C.sub.10-aryl, di(C.sub.1-C.sub.6)alkylamino, (C.sub.1-C.sub.6)alkylthio, C.sub.6-C.sub.10-arylthio, SO.sub.3H, SO.sub.2NR.sup.9R.sup.10, CO.sub.2R.sup.11, CONR.sup.9R.sup.10, NHCOR.sup.12 or CO—C.sub.6-C.sub.10-aryl, wherein R.sup.9, R.sup.10, R.sup.11, R.sup.12 are the same or different and independently represent are hydrogen or C.sub.1-C.sub.6-alkyl.

2. The plastic material as claimed in claim 1, wherein Rc is phenyl, naphthyl, a heteroaryl of formula (B) or formula (C) ##STR00021## wherein Re and Rf are, independently of each other, hydrogen, C.sub.1-C.sub.20 alkyl or phenyl; or Rc is (C.sub.2-C.sub.4) alkenylen (C.sub.6-C.sub.10) aryl, C.sub.1-C.sub.4-alkylen-C.sub.6-C.sub.10-aryl, the aryl and heteroaryl radicals optionally being substituted by hydroxyl, C.sub.1-C.sub.4-alkyl, C.sub.1-C.sub.4 alkoxyl, C.sub.6-C.sub.10 aryloxy, Cl, cyano, C.sub.6-C.sub.10-aryl, or CO—C.sub.6-C.sub.10-aryl.

3. The plastic material as claimed in claim 2, wherein Rc is phenyl, naphthyl, a heteroaryl of formula (B), wherein Re and Rf are independently of each other hydrogen or C.sub.1-C.sub.2 alkyl; or Rc is C.sub.2-alkenylen (C.sub.6-C.sub.10) aryl, C.sub.1-C.sub.2-alkylen-C.sub.6-C.sub.10-aryl, the aryl and heteroaryl radicals optionally being substituted by hydroxyl, methyl, methoxy, C.sub.6-C.sub.10 aryloxy, Cl, C.sub.6-C.sub.10-aryl, or CO—C.sub.6-C.sub.10-aryl.

4. The plastic material as claimed in claim 1, wherein the transition metal catalyst is in the form of a transition metal salt with the metal selected from group consisting of the first, second and third transition series of the Periodic Table.

5. The plastic material as claimed in claim 4, wherein the metal is selected from the group consisting of manganese II, manganese III, iron II, iron III, cobalt II, cobalt III, nickel II, nickel III, copper I, copper II, rhodium II, rhodium III, rhodium IV, ruthenium I, ruthenium II and ruthenium IV.

6. The plastic material as claimed in claim 1, wherein the plastic material is or is part of a packaging article.

7. The plastic material as claimed in claim 6, wherein the packaging article is a container, a film or a sheet.

8. The plastic material as claimed in claim 1, wherein the additive (b) is used in an amount of from 0.001 to 5% by weight, based on the total weight of the plastic material and the additive.

9. The plastic material as claimed in claim 1, wherein the transition metal catalyst is used in an amount of from 0 to 1% by weight, based on the total weight of the plastic material and the additive.

10. A composition Z comprising the components A, B, and C, wherein the component A is a plastic material selected from the group consisting of polyesters, polyolefins, polyolefin copolymers and polystyrenes; the component B is an additive of the formula (1), ##STR00022## wherein Ra is a group of formula (A), ##STR00023## wherein Rb is selected from the group consisting of hydrogen, C.sub.1-C.sub.6 alkyl, C.sub.1-C.sub.6 alkoxy and —CO—C.sub.1-C.sub.4 alkyl; Rc is C.sub.7-C.sub.20 alkyl, C.sub.6-C.sub.10 aryl, C.sub.4-C.sub.10 heteroaryl, wherein the heteroatoms are N, O and/or S, (C.sub.2-C.sub.6)-alkenylen-(C.sub.6-C.sub.10) aryl, C.sub.1-C.sub.6-alkylen-C.sub.6-C.sub.10-aryl, the aryl and heteroaryl radicals optionally being substituted by hydroxyl, C.sub.1-C.sub.6-alkyl, C.sub.1-C.sub.6 alkoxyl, C.sub.6-C.sub.10 aryloxy, halogen, cyano, nitro, C.sub.6-C.sub.10-aryl, di(C.sub.1-C.sub.6)alkylamino, (C.sub.1-C.sub.6)alkylthio, C.sub.6-C.sub.10-arylthio, SO.sub.3H, SO.sub.2NR.sup.9R.sup.10, CO.sub.2R.sup.11, CONR.sup.9R.sup.10, NHCOR.sup.12 or CO—C.sub.6-C.sub.10-aryl; and the component C is a transition metal catalyst.

11. The composition as claimed in claim 10, further comprising component D, selected from the group consisting of aliphatic polyamides and partially aromatic polyamides.

12. The composition as claimed in claim 10, containing of from 14 to 99.887% by weight of component A; of from 0.01 to 70% by weight of component B; of from 0.003 to 15% by weight of component C; of from 0 to 80% by weight of a component D; with the % by weight being based in each case on the total weight of the composition Z; and with the weight percent of the components A, B, C and optionally, D always adding up to 100%.

13. The composition as claimed in anyone of claim 10, which is a masterbatch MB or a compound CO.

14. The plastic material as claimed in claim 1, wherein the transition metal catalyst is used in an amount of from 0.001 to 1%, by weight, based on the total weight of the plastic material and the additive.

15. The plastic material as claimed in claim 1, wherein the transition metal catalyst is used in an amount of from 0.01 to 0.5%, by weight, based on the total weight of the plastic material and the additive.

Description

EXAMPLES

[0190] % by weight mentioned in the following examples are based on the total weight of the mixture, composition or article; parts are parts by weight;

[0191] “ex” means example; “cpex” means comparative example; MB means masterbatch; CO means compound; unless indicated otherwise.

[0192] Substances Used

[0193] Component A1:

[0194] Polyethylene terephthalate (PET) having a density from 1.35 to 1.45 g/cm.sup.3 and intrinsic viscosity from 0.74 to 0.78 dl/g (ASTM D3236-88).

[0195] Component A2:

[0196] Polybutylene terephthalate (PBT) having a density from 1.28 to 1.32 g/cm.sup.3 and intrinsic viscosity from 0.90 to 1.00 dl/g (ASTM D3236-88).

[0197] Component B1:

##STR00006##

[0198] Component B2:

##STR00007##

[0199] Component B3:

##STR00008##

[0200] Component B4:

##STR00009##

[0201] Component B5:

##STR00010##

[0202] Component B6:

##STR00011##

[0203] Component B7:

##STR00012##

[0204] Component B8:

##STR00013##

[0205] Component B9:

##STR00014##

[0206] Component B10:

##STR00015##

[0207] Component B11:

##STR00016##

[0208] Component B12:

##STR00017##

[0209] Component B13:

##STR00018##

[0210] Component C1:

[0211] Cobalt stearate (9.5% Cobalt concentration).

[0212] Component D1:

[0213] Poly(m-xylylene adipamide) (MXD6) having a density from 1.20 to 1.30 g/cm.sup.3 and MFR of 2 g/10 min (measured at 275° C./0.325 kg).

[0214] Component D2:

[0215] Comparative product: Amosorb® 4020E polyester resin (ColorMatrix, US), which is a PET copolymer containing polybutadiene segments and a cobalt salt to give elemental cobalt level of 50 ppm.

[0216] Masterbatches MB1 to MB13

[0217] Component A1 was dried at 160° C. for 7 hrs and then the other components were homogenized and mixed in the ratios according to Table 2. The components were homogenized together on a Leistritz® ZSE18HP extruder at a temperature of 230° C. to obtain solid masterbatches MB1 to MB13.

TABLE-US-00002 TABLE 2 A1 B1 B2 B3 B4 B5 B6 B7 B8 B9 B10 B11 B12 C1 D1 D2 MB1 95 4 1 MB2 95 4 1 MB3 95 4 1 MB4 95 4 1 MB5 95 4 1 MB6 95 4 1 MB7 95 4 1 MB8 95 4 1 MB9 95 4 1 MB10 95 4 1 MB11 95 4 1 MB12 95 4 1 MB13 8 92 (comp)

Ex1 to Ex3 and Cpex1 to Cpex3

[0218] Component A1 was dried at 160° C. for 7 hrs and then the other components were homogenized and mixed in the ratios according to Table 3.

[0219] The obtained Compounds CO1 to CO6 were used to manufacture 500 ml bottles via a two-step ISBM process. 23 gram preforms were firstly prepared on an injection molding machine Arburg® 420C 1000-150 and then cooled to room temperature prior to the stretch blow molding step on a Sidel® SBO-1.

[0220] As an example of operational mode, preforms were obtained via injection molding by using the Arburg® 420C 1000-150 by inserting the component A1, pre-dried for 6 hours at 160° C., into the main hopper of the machine, and by adding the other components (MB1 to MB13 or D2) through dosing units applied to the main stream of component A1 before entering the injection unit barrel. Barrel temperatures can be kept at temperatures between 270 and 295° C.; cycle time can vary between 14 and 16 seconds.

[0221] The weight of the preforms is chosen accordingly to the standard preforms found in the market, and can be set e.g. at 23 g per preform. The mould can be cooled by using water at e.g. 8° C. Once extracted from the mould, preforms can be collected in order to be successively blown by using a Sidel® SBO-1 blow forming unit. This unit, equipped e.g. with a mould for 500 ml (nominal capacity) bottle, comprises a heating zone where preforms are heated at temperatures variable with the design of the preform and of the final bottle; the final temperature of the preforms is kept between 105 and 110° C.; preforms are then inserted in the bottle moulds and blown by injecting dry air or nitrogen with a profile of pressure reaching 35-40 bar at its maximum, the blowing process requiring 2 to 3 seconds time. The average production rate was 900 bottles per hour.

[0222] Blown bottles are then collected from the blowing unit for the necessary testing.

[0223] CO5 consists of a transition metal-based polyester/polyamide composition, prepared according to the state of the art and thus, not comprising component B.

[0224] CO6 consists of a composition formulated with Amosorb® resin, not comprising component B.

TABLE-US-00003 TABLE 3 Components used [parts] ex-cpex Compounds A1 MB1 MB4 MB11 MB13 D2 cpex 1 CO1 (virgin PET) 100 ex1 CO2 85 15 ex2 CO3 85 15 ex3 CO4 85 15 cpex2 CO5 95 5 cpex3 CO6 98 2

[0225] Total haze is the preferred method of measuring the clarity of polyester articles, which can determine its suitability for packaging application as clear barrier compositions. Haze was measured on polyester bottles obtained from compounds CO1 to CO6 as described above. Table 4 gives the details.

[0226] Compositions CO2 to CO4 of the present invention clearly show a significant improvement in clarity compared to the state-of-the-art compositions CO5 and CO6 not comprising component B. The level of clarity from inventive compositions is very similar to the virgin PET in CO1 (Haze: 1.5%).

TABLE-US-00004 TABLE 4 compound CO1 CO2 CO3 CO4 CO5 CO6 Haze (%) 1.5 1.9 1.8 1.9 9.5 8

[0227] The oxygen scavenging activity corresponding to bottles prepared with compounds CO1 to CO6 was then measured by following the method described above. In table 5, the ingress of oxygen (in ppm) measured for compositions CO1 to CO6 is reported against the time elapsed from the filling of the container (measured in days). Inventive compositions CO2 to CO4 show an oxygen uptake well below 1 ppm after 120 days of measurement.

TABLE-US-00005 TABLE 5 Time Ingress of oxygen [ppm] [days] CO1 CO2 CO3 CO4 CO6 0 0 0 0 0 0 26 1.50 0.70 0.76 0.80 0 35 2.00 0.70 0.80 0.83 0.03 68 0.76 0.78 0.8 0.65 89 0.73 0.72 0.78 1.7 120 0.65 0.61 0.76 2.3