Compositions containing polyanion, ethoxylated cationic polymer and phyllosilicates for improved oxygen barrier coatings

Abstract

Described is an aqueous composition comprising (a) at least one polyanion, (b) at least one ethoxylated cationic polymer, and (c) at least one phyllosilicate. The composition can be used for providing oxygen barrier properties to a polymer film.

Claims

1. An aqueous composition, comprising: (a) at least one polyanion; (b) at least one ethoxylated cationic polymer; and (c) at least one phyllosilicate.

2. The aqueous composition of claim 1, wherein the aqueous composition comprises: (a) the at least one polyanion in a range of 10 to 90 wt. %, with respect to a solids content of the aqueous composition; (b) the at least one ethoxylated cationic polymer in a range of 10 to 90 wt. %, with respect to the solids content; and (c) the at least one phyllosilicate in a range of 5 to 75 wt. %, with respect to the solids content.

3. The aqueous composition of claim 1, wherein the at least one polyanion (a) and the at least one ethoxylated cationic polymer (b) are dissolved in the aqueous composition and wherein the at least one polyanion (a) is a polymer comprising acid groups neutralized with at least one base selected from the group consisting of an inorganic base and a monovalent organic base, said polymer comprising acid groups having a weight average molecular weight of at least 10000 g/mol prior to neutralization and wherein said at least one ethoxylated cationic polymer (b) has a weight average molecular weight of at least 2500 g/mol.

4. The aqueous composition of claim 1, wherein a weight ratio of the at least one polyanion (a), calculated without neutralizing agent, to the at least one ethoxylated cationic polymer (b) is in a range of 10:1 to 10:5 and wherein a weight ratio of the sum of the at least one polyanion (a) and the at least one ethoxylated cationic polymer (b) to the at least one phyllosilicate (c) is in a range of 95:5 to 50:50.

5. The aqueous composition of claim 1, wherein the at least one polyanion is a polymer produced from monomers selected from the group consisting of a monoethylenically unsaturated C.sub.3 to C.sub.10 carboxylic acid, vinylsulfonic acid, styrenesulfonic acid, acrylamidomethylpropanesulfonic acid, vinylphosphonic acid, and a salt thereof.

6. The aqueous composition of claim 1, wherein the at least one polyanion (a) is a neutralized polyacrylic acid or a neutralized copolymer of acrylic acid and maleic acid, and a weight average molecular weight of the at least one anionic polymer (a) is in a range of 10,000 to 200,000 g/mol.

7. The aqueous composition of claim 1, wherein a degree of ethoxylation of the at least one ethoxylated cationic polymer (b) is in a range of 40:1 to 1:10 based on a weight amount of CH2CH2O-units to the other polymer components, and a weight average molecular weight of the at least one ethoxylated cationic polymer (b) is in a range of 2500 to 3 million g/mol.

8. The aqueous composition of claim 1, wherein the at least one phyllosilicate (c) is an exfoliated organically modified smectite.

9. The aqueous composition of claim 1, wherein the at least one phyllosilicate (c) is a natural or synthetic phyllosilicate with an aspect ratio greater than 400.

10. The aqueous composition of claim 1, wherein the at least one phyllosilicate (c) is a synthetic smectite of the formula: [M.sub.n/valency].sup.inter [M.sup.I.sub.mM.sup.II.sub.o].sup.oct [Si.sub.4].sup.tet O.sub.10 Y.sub.2, wherein M is H.sup.+ or a metal cation with an oxidation state of 1 to 3, M.sup.I is a metal cation with an oxidation state of 2 or 3, M.sup.II is a metal cation with an oxidation state of 1 or 2, O is oxygen, Y is a mono-anion, m is 2.0 for each M.sup.I metal cation with an oxidation state of 3, and 3.0 for each M.sup.I metal cations with an oxidation state of 2, o is 1.0, and n, the layer charge, is in a range of 0.01 to 2.0.

11. The aqueous composition of claim 1, wherein a surface of the at least one phyllosilicate (c) comprises an organic compound comprising at least one group selected from the group consisting of an amino group and an ammonium group.

12. The aqueous composition of claim 1, wherein the at least one phyllosilicate (c) is hydrothermally produced or is produced by high-temperature melt synthesis and subsequent exfoliation and/or delamination.

13. The aqueous composition of claim 1, wherein the at least one ethoxylated cationic polymer (b) is selected from the group consisting of an ethoxylated vinylimidazolium polymer, an ethoxylated diallyl dimethyl ammonium halide polymer, an ethoxylated vinylamine polymer, an ethoxylated ethylene imine polymer, an ethoxylated dialkylaminoalkyl acrylate polymer, an ethoxylated dialkylammoalkyl methacrylate polymer, an ethoxylated dialkylaminoalkyl acrylamide polymer and an ethoxylated dialkylaminoalkyl methacrylamide polymer.

14. The aqueous composition of claim 1, wherein the at least one ethoxylated cationic polymer (b) is an ethoxylated polyalkylenimine or an ethoxylated polyamine of formula I: ##STR00009## wherein: R represents identical or different, linear or branched C.sub.2-C.sub.12-alkylene radicals or an etheralkyl unit of the following formula: ##STR00010## wherein: R.sup.10, R.sup.11,R.sup.12 represent identical or different, linear or branched C.sub.2-C.sub.6-alkyline radicals, and d is an integer in a range of 0 to 50; B represents a continuation of the ethoxylated polyalkylenimine or the ethoxylated polyamine by branching; E is an alkylenoxy unit of the formula II, wherein the alkylenoxy units may be in any order ##STR00011## wherein: R.sup.1 represents 1,2-propylene, 1,2-butylene, 1,2-isobutylene and/or 1,2-pentene; R.sup.2 represents hydrogen and/or C.sub.1-C.sub.22-alkyl and/or C.sub.7-C.sub.22 aralkyl; m is an integer in a range of 5 to 50; n is an integer in a range of 0 to 40; y and z are each from 0 to 150, where the sum of y+z is at least 1; wherein a number of ethyleneoxy groups is more than 50% of all alkylenoxy groups.

15. The aqueous composition of claim 1, wherein the at least one ethoxylated cationic polymer (b) is an ethoxylated polyethyleneimine.

16. A polymer film, coated with the aqueous composition of claim 1.

17. The polymer film of claim 16, wherein an oxygen transmission rate of the polymer film after coating is less than 40% of an oxygen transmission rate of the polymer film before coating, both rates being measured at 25 C. and 75% relative humidity.

18. The polymer film of claim 16, wherein the polymer film comprises at least one material selected from the group consisting of a polyethylene terephthalate, an oriented polypropylene, a polyethylene, a casted polypropylene, a biodegradable aliphatic-aromatic copolyester, a metalized polyethylene terephthalate, a metalized oriented polypropylene and a polyimide, and wherein a thickness of a coating layer is in a range of 0.2 to 50 m after drying.

19. A package, comprising the polymer film of claim 16.

20. A method of coating a polymeric film with the aqueous composition of claim 1, the method comprising: (a) contacting at least one side of the polymeric film with the aqueous composition and (b) drying said aqueous composition to form a barrier coating on the polymeric film.

Description

EXAMPLES

(1) Measurement of Oxygen-barrier Action:

(2) Oxygen transmission rate (OTR) is determined on coatings on polymer films at a relative humidity (RH) level of 75% and at a temperature of 25 C.

(3) Measurements are done with synthetic air (21% oxygen; results are extrapolated for 100% oxygen.

(4) Carrier material: polymer film of PET (polyethylene terephthalate) with a thickness of 50 m. OTR of the uncoated film: 27.40.2 cm.sup.3/(m.sup.2*d).

(5) The determination method is based on ASTM D3985-05, using a coulometric sensor. Each sample is measured twice and the mean result is calculated.

(6) OTR are obtained on a Mocon OX-TRAN 2/21 XL instrument with a lower detection limit of 0.0005 cm.sup.3 m.sup.2 day.sup.1 bar.sup.1.

(7) Water vapour transmission rates (WVTR) were measured on a Mocon PERMATRAN-W model 333 at 25 C. and a relative humidity of 75% RH. The lower detection limit of the device was 0.05 g m.sup.2 day.sup.1.

(8) Polymer Samples: PEI1 33 wt. % aqueous solution of polyethyleneimine, Mw=750000 g/mol; charge density 17 meq/g, pH=11 PEIE ethoxylated polyethyleneimine, 80 wt. % in water; Mw=13000 g/mol molar ratio of ethylene oxide units to ethyleneimine units=20:1 (degree of ethoxylation=20.5:1)

(9) ##STR00005## PAA polyacrylic acid, Mw=100000 g/mol; 35 wt % in water, PPE1 polyelectrolyte complex made from PAA and PEIE in a weight ratio of 70:30, pH 4.3 PPE2 polyelectrolyte complex made from PAA and PEIE in a weight ratio of 90:10, pH 4.2 PPE3 polyelectrolyte complex made from PAA and PEIE in a weight ratio of 70:30, pH 3.3

(10) Phyllosilicates: Na-hect synthetic sodium fluorohectorite L-hect hectorite modified with L-lysine BT-hect hectorite modified with betaine Tris-hect hectorite modified with 2-Amino-2-(hydroxymethyl)-1,3-propanediol (TRIS)

(11) Modification Agents: L-lysine: (S)-2,6-Diaminohexanoic acid monohydrochloride C.sub.6H.sub.14N.sub.2O.sub.2.HCl, reagent grade 98%, Sigma-Aldrich GmbH, Germany.

(12) ##STR00006## Betaine: N,N,N-trimethylglycine (anhydrous), C.sub.5H.sub.11NO.sub.2, Alfa Aesar GmbH, Germany

(13) ##STR00007## TRIS: 2-Amino-2-(hydroxymethyl)-1,3-propanediol, C.sub.4H.sub.11NO.sub.3, reagent grade 99.9%, Sigma-Aldrich GmbH, Germany. The pH of 0.5 M solution of TRIS was adjusted to 5.75 with hydrochloric acid.

(14) ##STR00008##

(15) The type of phyllosilicate used in the examples is exfoliated smectite type with layer charge of 0.5 per formula unit (p.f.u.). The synthesis procedure of the used phyllosilicate is described in M. Stoter, D. A. Kunz, M. Schmidt, D. Hirsemann, H. Kalo, B. Putz, J. Senker, J. Breu, Langmuir 2013, 29, 1280-1285. The phyllosilicate is a synthetic sodium fluorohectorite (Na-hect) and has a cation exchange capacity of 127 meq/100 g. The chemical formula is:
[Na.sub.0.5.xH.sub.2O].sup.int[Mg.sub.2.5Li.sub.0.5].sup.oct[Si.sub.4].sup.tetO.sub.10F.sub.2

(16) Modification of the Sodium Fluorohectorite:

(17) Different type of cationic modification where used to replace sodium cations from the surface of the delaminated layered silicate. Modification provides stabilization of the delaminated layered silicates and compatibilization of the layered silicate with the polymer matrix within the suspension and in the drying step of film-formation.

Example 1: Modifying Delaminated Na-hect

(18) In a 50 ml centrifuge tube 0.25 g of Na-hect was suspended in 30 ml of distillate water. For the surface modification of the Na-hect a 125% of CEC (cation exchange capacity) of the modification agent (after dissolved in 5 ml distillate water) was added and placed into an overhead shaker for 12 h. Afterward the modified Na-hect was centrifuged at 10000 rpm, the separated supernatant was discarded and the modified Na-hect was re-suspended in distillate water and again a 125% of CEC of the modification agent (after dissolved in 5 ml distillate water) was added and placed into an overhead shaker for 12 h to ensure complete surface modification of Na-hect. At last the modified Na-hect was centrifuged at 10000 rpm and the separated supernatant was discarded and the modified Na-hect was washed with distilled water washed until the conductivity of the separated supernatant was below 25 s.

Example 2: Mixing of Polyanion (PAA) with Ethoxylated Polyethyleneimine (PEIE) in a 70:30 Weight Ratio to Form Polyelectrolyte Complex (PPE1)

(19) 8 g of the solution of PAA in water with 35 wt % solid content was mixed with 2.5 ml of a 3M solution of NH.sub.3 in water and then 1.5 g of a 80 wt.-% (solution in water) of PEIE was added. 5 ml of distilled water was added to the mixture and mixed via magnetic stirring for 4 h.

(20) pH: 4.3

(21) A mixture of the resulting PPE1 was coated on a PET substrate with speed blade 18 mm/s. The film was dried at 80 C. for 24 h and the OTR and WVTR were measured (see table 1).

Example 3: Suspension of Modified Phyllosilicate Na-hect with a Matrix Polyelectrolyte Complex (PPE1) with Weight Ratio 50:50

Example 3a: Modification with Betain (BT-hect50)

(22) The amount of a Na-hect modified with BT according to procedure illustrate in example 1 was added to the required amount of PPE1 to produce a suspension with 50 wt. % (based on inorganic material, i.e. without modification agent) of phyllosilicate layer silicate in the final solid matrix (the amount of modification agent was calculated on the side of polymer). The final suspension ready to coating has a solid content of 2 wt %.

(23) The suspension was deposited on PET foils using doctor-blading with speed of blade 18 mm/s. The film was dried at 80 C. for 24 h and the OTR and WVTR were measured (see table 1).

Example 3b Modification with TRIS (Tris-hect50)

(24) The procedure of example 3a was applied to prepare nanocomposites using TRIS as modification of Na-hect.

(25) The coated film was dried at 80 C. for 24 h and the OTR and WVTR were measured at 25 C. and 75% RH (see table 1).

Example 3c: Modification with L-lysine (L-hect)

(26) The procedure of example 3a was applied to prepare nanocomposite using L-lysine as modification of Na-hect with various amounts of L-hect: Example 3c: 50 wt.-% inorganic material (L-hect50) Example 3c1: 10 wt.-% inorganic material (L-hect10) Example 3c2: 20 wt.-% inorganic material (L-hect20) Example 3c3: 30 wt.-% inorganic material (L-hect30) Example 3c4: 40 wt.-% inorganic material (L-hect40)

(27) The coated film was dried at 80 C. for 24 h and the OTR and WVTR were measured at 25 C. and 75% RH (see table 1).

Example 4: Mixing of Polyanion (PAA) with Ethoxylated Polyethyleneimine (PEIE) in a 90:10 Weight Ratio to Form Polyelectrolyte Complex (PPE2)

(28) 12.86 g of the solution of PAA in water with 35 wt % solid content was mixed with 4.2 ml of 3M solution of NH.sub.3 in water, then 5 ml of distilled water were added and the mixture was mixed via magnetic stirring for 30 min. Then 0.63 g of 80 wt.-% solution in water of PEIE was added. The whole mixture was then homogenized via magnetic stirring for 4 h.

(29) pH: 4.2

(30) A mixture of the resulting PPE2 was coated on a PET substrate with blade speed of 18 mm/s. The film was dried at 80 C. for 24 h (see table 1).

Example 4a1: PPE2+BT-hect

(31) The procedure of example 3a was applied to prepare nanocomposites using betaine as modification of Na-hect and PPE2 (example 4) as polymer matrix. The amount of inorganic silicate material was 10 wt.-% of phyllosilicate in final solid matrix.

(32) The coated film was dried at 80 C. for 24 h and the OTR and WVTR were measured at 25 C. and 75% RH (see table 1).

Example 4a2: PPE2+L-hect

(33) The procedure of example 3a was applied to prepare nanocomposites using L-lysine as modification of Na-hect and PPE2 (example 4) as polymer matrix. The amount of inorganic silicate material was 10 wt.-% of phyllosilicate in final solid matrix.

(34) The coated film was dried at 80 C. for 24 h and the OTR and WVTR were measured at 25 C. and 75% RH (see table 1).

Example 5 PPE3

(35) 8 g of the solution of PAA (35 wt % solid content in water) was mixed with 0.75 ml of 3M solution of NH.sub.3 in water and then 1.5 g of a 80 wt.-% solution in water of PEIE was added. 5 ml of distilled water was added to the mixture and mixed via magnetic stirring for 4 h.

(36) pH: 3.3

(37) A mixture of the resulting PPE3 was coated on a PET substrate with speed blade 18 mm/s. The film was dried at 80 C. for 24 h and the OTR and WVTR were measured (see table 1).

Example 5a1 PPE3+L-hect

(38) The procedure of example 3a was applied to prepare nanocomposites using L-lysine as modification of Na-hect and PPE3 (example 5) as polymer matrix. The amount of inorganic silicate material was 20 wt.-% of phyllosilicate in final solid matrix.

(39) The coated film was dried at 80 C. for 24 h and the OTR and WVTR were measured at 25 C. and 75% RH (see table 1).

Example 6 (Comparative)

(40) Suspension of modified phyllosilicate Na-hect with a matrix polyelectrolyte complex of PAA and not-ethoxylated PEI1.

(41) The procedure of example 3a was applied to prepare nanocomposite using L-lysine as modification of Na-hect and using 100 parts by weight PAA and 40 parts by weight of PEI1 instead of PEIE.

Example 7 (Comparative): PAA+L-hect (100:20)

(42) The procedure of example 3a was applied to prepare nanocomposite using L-lysine as modification of Na-hect and using 100 parts by weight PAA only, i.e. without PEIE. The amount of inorganic silicate material was 20 wt.-% of phyllosilicate in final solid matrix.

Example 8 (Comparative): PAA+L-hect (100:50)

(43) The procedure of example 3a was applied to prepare nanocomposite using L-lysine as modification of Na-hect and using 100 parts by weight PAA only, i.e. without PEIE. The amount of inorganic silicate material was 50 wt.-% of phyllosilicate in final solid matrix.

(44) TABLE-US-00001 TABLE 1 Oxygen barrier and water vapor barrier measurement results Thickness OTR WVTR Film pH [m] [cm.sup.3 m.sup.2 day.sup.1 bar.sup.1] [g m.sup.2 day.sup.1] Uncoated PET 50 27.4 (0.2) 4.67 substrate (comp.) Ex. 2 4.3 8 25.4 (0.1) 4.27 PPE1 (comp.) Ex. 3a BT-hect50 4.5-5 3 0.11 (0.01) 0.34 .sup.0.010 .sup.1) .sup.0.08 .sup.1) Ex 3b T-hect50 4.5-5 2.5 0.54 (0.03) 0.53 Ex. 3c L-hect50 4.5-5 2.4 0.2 (0.02) 0.30 .sup.0.020 .sup.1) .sup.0.08 .sup.1) Ex. 3c1 L-hect10 4.5 2 10.2 1.5 Ex. 3c2 L-hect20 4.7 2 8.38 1.21 Ex. 3c3 L-hect30 4.8 1-2 6.41 0.90 Ex. 3c4 L-hect40 5 1-2 4.65 0.77 Ex. 4 4.2 8 21.4 3.2 PPE2 (comp.) Ex. 4a1 4.5 2 8.02 2.95 PPE2 + BT-hect Ex. 4a2 4.5 2 8.23 1.4 PPE2 + L-hect Ex. 5 PPE3 3.3 13-14 22.78 2.96 (comp.) Ex. 5a1 3.5 4 0.82 0.53 PPE3 + L-hect Ex. 6 (comp.) No stable No stable No stable PAA/PEI + L-hect formulation formulation formulation Ex. 7 (comp.) 3-4 14.6 3.8 PAA + L-hect 100:20 Ex. 8 (comp.) 1-2 10.3 2.1 PAA + L-hect 100:50 .sup.1) Film dried for 48 hours

Example 9: Modification with L-lysine (L-hect50) for Spray Coating

(45) The procedure of example 3a was applied to prepare nanocomposite using L-lysine as modification of Na-hect and PPE1. The final formulation contained 20 wt.-% of inorganic material, based on solids with a total solids content of 2 wt.-%.

Example 10: Modification with L-lysine (L-hect50) for Spray Coating

(46) Same composition as Example 9, but with a total solids content of 1 wt.-%.

(47) The compositions of examples 9 and 10 were spray coated on a PET substrate (Optimont BOPET-film; 100 m) and the OTR and WVTR were measured (see table 2).

(48) Spray Coating Parameters:

(49) 55 cycles (example 9); 110 cycles (example 10) Spray device: SATAjet 4000 LAB HVLP 1.0 mm Carrier gas: air; inlet pressure 4 bar; outlet pressure 2-4 bar Flow rate carrier gas: about 450 l/min at 2.5 bar Flow rate suspension: 60 ml/min Uniaxial application Treadmill speed 1 m/sec Drying: 60 sec at 60 C. with 250 W IR lamps

(50) TABLE-US-00002 TABLE 2 Oxygen barrier and water vapor barrier measurement results for spray coated samples Coating thickness OTR WVTR Film [m] [cm.sup.3 m.sup.2 day.sup.1 bar.sup.1] [g m.sup.2 day.sup.1] Uncoated PET 0 11.5 1.8 substrate 100 m Ex. 9 2-3 6.68 .Math. 10.sup.3 <0.005 Ex. 10 4-6 7.19 .Math. 10.sup.4 <0.005