EVOH barrier film with reduced autoclave shock
View Patent ↗The presently disclosed subject matter is directed to a barrier film that maintains an oxygen barrier after being subjected to autoclaving conditions. The film comprises one EVOH layer positioned as a core layer, and one EVOH layer positioned directly adjacent to an outer layer comprising highly permeable material having a moisture vapor permeability greater than about 40 g-mil/100 in 2 -day-atm. During autoclaving, the barrier properties of the EVOH layer positioned adjacent to the outer layer allows improved recovery of oxygen barrier properties. In addition, during rewetting applications, the internal EVOH layer maintains the oxygen barrier. Also disclosed are methods of making and using the disclosed barrier film.
1. A method of packaging an oxygen sensitive product, the method comprising:
a. providing a film comprising:
i. a first layer comprising a high permeable material having a moisture vapor permeability greater than about 40 g-mil/100 in 2 -day-atm;
ii. a second layer directly adjacent to the first layer comprising EVOH;
iii. a first region defining a third layer in direct contact with the second layer comprising 1 to 5 distinct sublayers comprising low permeable materials having moisture vapor permeability of less than about 20 g-mil/100 in 2 -day-atm;
iv. a fourth layer comprising EVOH;
v. a second region defining a fifth layer in direct contact with the fourth layer comprising 1 to 5 sublayers comprising very low permeable materials having a moisture vapor transmission rate of less than about 5 g/100 in 2 -day-atm;
b. forming the film into a pouch;
c. filling the pouch with an oxygen sensitive product;
d. sealing the pouch; and
e. subjecting the packaged product to autoclave conditions.
2. The method of claim 1 , wherein the first layer of said film comprises at least one member selected from the group consisting of: a polyamide, an elastomeric copolyamide, and a polyether polyamide block copolymer.
3. The method of claim 2 , wherein the polyamide is selected from the group consisting of: nylon 6, nylon 7, nylon 8, nylon 9, nylon 10, nylon 2, nylon 11, nylon 12, nylon 66, nylon 69, nylon 610, nylon 611, nylon 612, nylon 6/12, nylon 6/69, nylon 66/610, nylon 6/66, nylon 66/6, nylon 12T, nylon 6T, and combinations thereof.
4. The method of claim 2 , wherein the elastomeric copolyamide is selected from the group consisting of: copolymers of a polyamide and a polyetheramine, copolymers of nylon 12 and a polyetheramine, and copolymers of nylon 69 and a polyetheramine.
5. The method of claim 1 , wherein the EVOH of the second and fourth layers comprises an ethylene content of between about 28 mol % and about 48 mol %.
6. The method of claim 1 , wherein at least one of the layers of the first and second region in direct contact with the second or fourth layer comprises a polymeric adhesive selected from the group consisting of anhydride grafted ethylene/1-butene copolymer, anhydride grafted ethylene/1-hexene copolymer, polypropylene, propylene ethylene copolymer, ethylene vinyl acetate copolymer, ethylene methyl acrylate copolymer, and anhydride grafted ethylene/1-octene copolymer.
7. The method of claim 1 , wherein at least one layer of the first or second region comprises a polymer selected from the group consisting of: ethylene alpha olefin copolymer, high density polyethylene, polypropylene, polypropylene ethylene copolymer, and cyclo-olefin copolymer.
8. The method of claim 1 , wherein the oxygen sensitive product is a medical product.