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) a polyanion; (b) an ethoxylated cationic polymer; and (c) a phyllosilicate.

2: The aqueous composition according to claim 1, wherein the aqueous composition comprises: (a) from 10 to 90 wt. %, referring to solids content, of the polyanion; (b) from 10 to 90) wt. %, referring to solids content, of the ethoxylated cationic polymer; and (c) from 5 to 75 wt. %, referring to solids content, of the phyllosilicate.

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

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

5: The aqueous composition according to claim 1, wherein the polyanion is selected from polymers produced from monomers selected from the group consisting of monoethylenically unsaturated C.sub.3 to C.sub.10 carboxylic acids, vinylsulfonic acid, styrenesulfonic acid, acrylamidomethylpropanesulfonic acid, vinylphosphonic acid, and salts thereof.

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

7: The aqueous composition according to any of claim 1, wherein a degree of ethoxylation of the ethoxylated cationic polymer (b) is from 40:1 to 1:10, and a weight average molecular weight of the ethoxylated cationic polymer (b) is from 2500 to 3 million g/mol.

8: The aqueous composition according to claim 1, wherein the phyllosilicate is selected from exfoliated organically modified smectites.

9: The aqueous composition according to claim 1, wherein the phyllosilicate is a natural or synthetic phyllosilicate with an aspect ratio of more than 400.

10: The aqueous composition according to claim 1, wherein the phyllosilicate 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.tetO.sub.10Y.sub.2, wherein M are metal cations of oxidation state 1 to 3 or H.sup.+, M.sup.I metal cations of oxidation state 2 or 3, M.sup.II are metal cations of oxidation state 1 or 2, X are di-anions and Y are mono-anions, m for metal atoms M.sup.I of oxidation state 3 is 2.0 and m for metal atoms M.sup.I of oxidation state 2 is 3.0, o is 1.0 and the layer charge n is from greater or equal 0.01 to lower or equal 2.0.

11: The aqueous composition according to claim 1, wherein the phyllosilicate is surface-modified with an organic compound having at least one group selected from amino groups and ammonium groups.

12: The aqueous composition according to claim 1, wherein the phyllosilicate is hydrothermally produced or is produced by high-temperature melt synthesis and subsequent exfoliation and/or delamination.

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

14: The aqueous composition according to claim 1, wherein the 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-alkylene radicals, and d is an integer having a value in the range of from 0 to 50; B represents a continuation of the ethoxylated polyalkylenimines or ethoxylated polyamines 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 having a value in the range of from 5 to 50; n is an integer having a value in the range of from 0 to 40; y and z are each from 0 to 150, where the sum of y+z is at least 1; wherein the number of ethyleneoxy groups is more than 50% of all alkylenoxy groups.

15: The aqueous composition according to claim 1, wherein the ethoxylated cationic polymer (b) is an ethoxylated polyethyleneimine.

16: A polymer film, coated with an aqueous composition according to claim 1.

17: The polymer film according to claim 16, wherein an oxygen transmission rate of the coated film is less than 40% of an oxygen transmission rate of the uncoated film, measured at 25 C. and 75% relative humidity.

18: The polymer film according to claim 16, wherein a material of the polymer film is selected from the group consisting of polyethylene terephthalate, oriented polypropylene, polyethylene, casted polypropylene, biodegradable aliphatic-aromatic copolyesters, metalized polyethylene terephthalate, metalized oriented polypropylene and polyamide, and wherein a thickness of the coating layer after drying is from 0.2 to 50 m.

19: A package comprising a polymer film according to claim 16.

20: A method of forming a polymeric film with enhanced oxygen barrier properties, the method comprising: applying an aqueous composition according to claim 1 to at least one side of a polymer film and drying said composition to form a barrier coating on the polymer film.

21: (canceled)

Description

EXAMPLES

[0171] Measurement of Oxygen-Barrier Action:

[0172] 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.

[0173] Measurements are done with synthetic air (21% oxygen; results are extrapolated for 100% oxygen.

[0174] 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).

[0175] The determination method is based on ASTM D3985-05, using a coulometric sensor. Each sample is measured twice and the mean result is calculated.

[0176] 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.

[0177] 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.

[0178] Polymer Samples: [0179] PEI1 33 wt. % aqueous solution of polyethyleneimine, Mw=750000 g/mol; charge density 17 meq/g, pH=11 [0180] 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)

##STR00005## [0181] PAA polyacrylic acid, Mw=100000 g/mol; 35 wt % in water, [0182] PPE1 polyelectrolyte complex made from PAA and PEIE in a weight ratio of 70:30, pH 4.3 [0183] PPE2 polyelectrolyte complex made from PAA and PEIE in a weight ratio of 90:10, pH 4.2 [0184] PPE3 polyelectrolyte complex made from PAA and PEIE in a weight ratio of 70:30, pH 3.3

[0185] Phyllosilicates: [0186] Na-hect synthetic sodium fluorohectorite [0187] L-hect hectorite modified with L-lysine [0188] BT-hect hectorite modified with betaine [0189] Tris-hect hectorite modified with 2-Amino-2-(hydroxymethyl)-1,3-propanediol (TRIS)

[0190] Modification Agents: [0191] 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.

##STR00006## [0192] Betaine: N,N,N-trimethylglycine (anhydrous), C.sub.5H.sub.11NO.sub.2, Alfa Aesar GmbH, Germany

##STR00007## [0193] 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.

##STR00008##

[0194] 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: [0195] [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

[0196] Modification of the Sodium Fluorohectorite:

[0197] 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

[0198] 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)

[0199] 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.

[0200] pH: 4.3

[0201] 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)

[0202] 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 %.

[0203] 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)

[0204] The procedure of example 3a was applied to prepare nanocomposites using TRIS as modification of Na-hect.

[0205] 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)

[0206] The procedure of example 3a was applied to prepare nanocomposite using L-lysine as modification of Na-hect with various amounts of L-hect: [0207] Example 3c: 50 wt.-% inorganic material (L-hect50) [0208] Example 3c1: 10 wt.-% inorganic material (L-hect10) [0209] Example 3c2: 20 wt.-% inorganic material (L-hect20) [0210] Example 3c3: 30 wt.-% inorganic material (L-hect30) [0211] Example 3c4: 40 wt.-% inorganic material (L-hect40)

[0212] 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)

[0213] 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.

[0214] pH: 4.2

[0215] 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

[0216] 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.

[0217] 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

[0218] 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.

[0219] 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

[0220] 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.

[0221] pH: 3.3

[0222] 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

[0223] 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.

[0224] 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)

[0225] Suspension of modified phyllosilicate Na-hect with a matrix polyelectrolyte complex of PAA and not-ethoxylated PEI1.

[0226] 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)

[0227] 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)

[0228] 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.

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

[0229] 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

[0230] Same composition as Example 9, but with a total solids content of 1 wt.-%.

[0231] 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).

Spray Coating Parameters:

[0232] 55 cycles (example 9); 110 cycles (example 10) [0233] Spray device: SATAjet 4000 LAB HVLP 1.0 mm [0234] Carrier gas: air; inlet pressure 4 bar; outlet pressure 2-4 bar [0235] Flow rate carrier gas: about 450 l/min at 2.5 bar [0236] Flow rate suspension: 60 ml/min [0237] Uniaxial application [0238] Treadmill speed 1 m/sec [0239] Drying: 60 sec at 60 C. with 250 W IR lamps

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