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US-12624177-B2 - Process for preparation of oxygen barrier film

US12624177B2US 12624177 B2US12624177 B2US 12624177B2US-12624177-B2

Abstract

The invention relates to a process for the preparation of an oxygen barrier film having an oxygen barrier layer and a treated substrate, comprising the steps of: a) subjecting a polyolefin substrate to a surface treatment to obtain the treated substrate wherein the surface under the parts of the curves corresponding to the C—O, C—N and C═O groups is at least 10% based on the total surface under the curve as obtained by X-ray photoelectron spectroscopy (XPS), b) applying an aqueous or hydroalcoholic coating composition comprising 0.1 to 25 wt % of polyvinyl alcohol, 0.1 to 30 wt % of a metal alkoxide and optional silicate minerals on the treated substrate obtained by step a) and c) drying the coating composition to obtain the oxygen barrier layer resulting in the oxygen barrier film, wherein the amount of the optional silicate minerals in the coating composition is less than 10 parts by weight per 100 parts by weight of the polyvinyl alcohol in the coating composition.

Inventors

  • Daniela Menozzi
  • Estelle Julie Mathilde Poulet
  • Maria Soliman
  • Enrico Dalcanale
  • Roberta PINALLI
  • Ilaria ALFIERI
  • Andrea LORENZI
  • Jerome Vachon

Assignees

  • SABIC GLOBAL TECHNOLOGIES B.V.

Dates

Publication Date
20260512
Application Date
20200416
Priority Date
20190429

Claims (19)

  1. 1 . A process for the preparation of an oxygen barrier film having an oxygen barrier layer and a treated substrate, the process comprising the steps of: a) subjecting a polyolefin substrate to a surface treatment to obtain a treated substrate wherein the surface under the parts of the curves corresponding to the C—O, C—N and C═O groups is at least 10% based on the total surface under the curve as obtained by X-ray photoelectron spectroscopy (XPS), b) applying an aqueous or hydroalcoholic coating composition comprising 0.1 to 25 wt % of polyvinyl alcohol, 0.1 to 30 wt % of a metal alkoxide and optional silicate minerals on the treated substrate obtained by step a) and c) drying the coating composition to obtain the oxygen barrier layer resulting in the oxygen barrier film, wherein the amount of the optional silicate minerals in the coating composition is less than 10 parts by weight per 100 parts by weight of the polyvinyl alcohol in the coating composition, wherein step a) is a plasma treatment performed at a pressure of 30 to 500 Pa, in air, at a power output of 55 to 80 W for a period of 30 to 100 seconds, and wherein the polyolefin substrate is a polyethylene substrate and the oxygen barrier film has an oxygen transmission rate of at most 100 cc/(m 2 ·24h), at a relative humidity of 0% and a pressure of 1.013×10 5 Pa.
  2. 2 . The process according to claim 1 , wherein the surface under the parts of the curves corresponding to the C—O, C—N and C═O groups is at least 15% based on the total surface under the curve as obtained by X-ray photoelectron spectroscopy (XPS) of the treated surface obtained by step a).
  3. 3 . The process according to claim 1 , wherein the metal alkoxide is a compound of the formula MRn, in which M is a metal atom, n is the valency of M and the groups R taken n times each independently represent an alkyl or alkyloxy radical having from 1 to 4 carbon atoms, provided that at least two of the groups R are alkyloxy radicals.
  4. 4 . The process according to claim 3 , wherein M is silicon (Si), aluminium (Al), zirconium (Zr) or titanium (Ti).
  5. 5 . The process according to claim 3 , wherein the metal alkoxide is tetraethoxysilane (TEOS).
  6. 6 . The process according to claim 1 , wherein the polyolefin substrate has a thickness of 7 to 500 μm.
  7. 7 . The process according to claim 1 , wherein the oxygen barrier layer has a thickness of 0.2 to 10.0 μm.
  8. 8 . The oxygen barrier film obtained by the process according to claim 1 .
  9. 9 . An article comprising the oxygen barrier film according to claim 8 .
  10. 10 . The article according to claim 9 , wherein the article is a packaging of food or a pharmaceutical product.
  11. 11 . The process according to claim 1 , wherein the oxygen transmission rate of the oxygen barrier film is at most 250 cc/(m 2 ·24h), at a relative humidity of 0% and a pressure of 1.013×10 5 Pa, after being stretched for 20% in one direction at a speed of 10 mm/min at 150 to 170° C.
  12. 12 . The process according to claim 1 , wherein (the oxygen transmission rate of the oxygen barrier film measured at a relative humidity of 0% and a pressure of 1.013×10 5 Pa after being stretched for 20% in one direction at a speed of 10 mm/min at 150° C.)−(the oxygen transmission rate of the oxygen barrier film measured at a relative humidity of 0% and a pressure of 1.013×10 5 Pa) is at most 200 cc/(m 2 · 24h).
  13. 13 . The process according to claim 12 , wherein OTR2 is at most 250 cc/(m 2 ·24h).
  14. 14 . The process according to claim 1 , wherein the pressure at which step a) is performed is 50 to 500 Pa.
  15. 15 . The process according to claim 1 , wherein the oxygen transmission rate of the oxygen barrier film is at most 50 cc/(m 2 ·24h), at a relative humidity of 0% and a pressure of 1.013×10 5 Pa.
  16. 16 . The process according to claim 1 , wherein the oxygen transmission rate of the oxygen barrier film is at most 20 cc/(m 2 ·24h), at a relative humidity of 0% and a pressure of 1.013×10 5 Pa.
  17. 17 . A process for the preparation of an oxygen barrier film having an oxygen barrier layer and a treated substrate, the process comprising the steps of: a) subjecting a polyolefin substrate to a surface treatment to obtain a treated substrate wherein the surface under the parts of the curves corresponding to the C—O, C—N and C═O groups is at least 10% based on the total surface under the curve as obtained by X-ray photoelectron spectroscopy (XPS), b) applying an aqueous or hydroalcoholic coating composition comprising 0.1 to 25 wt % of polyvinyl alcohol, 0.1 to 30 wt % of a metal alkoxide and optional silicate minerals on the treated substrate obtained by step a) and c) drying the coating composition to obtain the oxygen barrier layer resulting in the oxygen barrier film, wherein the amount of the optional silicate minerals in the coating composition is less than 10 parts by weight per 100 parts by weight of the polyvinyl alcohol in the coating composition, wherein the polyolefin substrate is a polypropylene substrate and the oxygen barrier film has an oxygen transmission rate of at most 50 cc/(m 2 ·24h), at a relative humidity of 0% and a pressure of 1.013×10 5 Pa, or the polyolefin substrate is a polyethylene substrate and the oxygen barrier film has an oxygen transmission rate of at most 100 cc/(m 2 ·24h), at a relative humidity of 0% and a pressure of 1.013×10 5 Pa.
  18. 18 . The process according to claim 17 , wherein the polyolefin substrate is a polypropylene substrate and the oxygen transmission rate of the oxygen barrier film is at most 50 cc/(m 2 ·24h), at a relative humidity of 0% and a pressure of 1.013×10 5 Pa.
  19. 19 . The process according to claim 17 , wherein the polyolefin substrate is a polyethylene substrate and the oxygen transmission rate of the oxygen barrier film is at most 100-20 cc/(m 2 ·24h), at a relative humidity of 0% and a pressure of 1.013×10 5 Pa.

Description

CROSS REFERENCE TO RELATED APPLICATIONS This application is a National Stage application of PCT/EP2020/060655, filed Apr. 16, 2020, which claims the benefit of European Application No. 19171617.4, filed Apr. 29, 2019, both of which are incorporated by reference in their entirety herein. FIELD OF THE INVENTION The invention relates to a process for the preparation of an oxygen barrier film. The invention further relates to an oxygen barrier film obtained or obtainable by the process and its applications such as in the packaging sector, for instance for the packaging of food or pharmaceutical products. BACKGROUND Materials suitable for use as a packaging should possess gas-barrier properties, in particular against oxygen, water vapour, carbon dioxide and other gases which could cause the content of the packaging to deteriorate. Commercially available package for potato chips typically uses aluminum oxide (AlOx) coated PET film. Integrity of packages can be lost during the storage and distribution due to the presence of defects in the seal area or package body as a result of abusive handling. In particular, abusive handling typically during shipments results in stretching of the film, which causes the deterioration of oxygen barrier property. EP1936004 discloses a method for producing a transparent barrier film for the purposes of packaging foodstuffs by a multistage vacuum plasma coating. The method comprises pretreating the substrate film by means of a plasma pretreatment; applying a thin incompletely closed first layer of aluminum oxide (AlOx) on the substrate film by magnetron sputtering, applying a closed second layer based on aluminum oxide (AlOx*) to the first layer by plasma-activated vapor deposition in vacuo. EP1936004 does not mention the deterioration of oxygen barrier property after stretching. WO2007/042993 discloses a laminated material comprising a substrate of a plastic material and at least one hybrid organic-inorganic layer having gas-barrier properties. The hybrid organic-inorganic layer is formed on the surface of the substrate by deposition of an aqueous or hydroalcoholic coating composition comprising polyvinyl alcohol and a metal alkoxide. WO2007/042993 does not mention the deterioration of oxygen barrier property after stretching. It is an objective of the invention to provide an oxygen barrier film which retains its oxygen barrier property even after stretching. SUMMARY OF THE INVENTION The present invention provides a process for the preparation of an oxygen barrier film having an oxygen barrier layer and a treated substrate, comprising the steps of: a) subjecting a polyolefin substrate to a surface treatment to obtain the treated substrate wherein the surface under the parts of the curves corresponding to the C—O, C—N and C═O groups is at least 10% based on the total surface under the curve as obtained by X-ray photoelectron spectroscopy (XPS),b) applying an aqueous or hydroalcoholic coating composition comprising 0.1 to 25 wt % of polyvinyl alcohol and 0.1 to 30 wt % of a metal alkoxide on the treated substrate obtained by step a) andc) drying the coating composition to obtain the oxygen barrier layer resulting in the oxygen barrier film. The present invention provides a process for the preparation of an oxygen barrier film having an oxygen barrier layer and a treated substrate, comprising the steps of: a) subjecting a polyolefin substrate to a surface treatment to obtain the treated substrate wherein the surface under the parts of the curves corresponding to the C—O, C—N and C═O groups is at least 10% based on the total surface under the curve as obtained by X-ray photoelectron spectroscopy (XPS),b) applying an aqueous or hydroalcoholic coating composition comprising 0.1 to 25 wt % of polyvinyl alcohol, 0.1 to 30 wt % of a metal alkoxide and optional silicate minerals on the treated substrate obtained by step a) andc) drying the coating composition to obtain the oxygen barrier layer resulting in the oxygen barrier film,wherein the amount of the optional silicate minerals in the coating composition is less than 10 parts by weight per 100 parts by weight of the polyvinyl alcohol in the coating composition. According to the invention, an oxygen barrier film is prepared from a polyolefin substrate by a surface treatment followed by the application and drying of a coating composition. It was surprisingly found that the oxygen barrier film obtained has a good oxygen barrier property even after stretching. This allows the oxygen barrier film to maintain its oxygen barrier property after abusive handling such as during transportation. The present invention further provides a surface treatment process comprising the step of: a) subjecting a polyolefin substrate to a surface treatment to obtain the treated substrate wherein the surface under the parts of the curves corresponding to the C—O, C—N and C═O groups is at least 10% based on the total surface under the curve as obtained by X-ray ph