Stock material or miscellaneous articles – Structurally defined web or sheet – Including components having same physical characteristic in...
Patent
1996-10-25
1998-06-23
Nakarani, D. S.
Stock material or miscellaneous articles
Structurally defined web or sheet
Including components having same physical characteristic in...
427387, 428215, 428216, 428447, 428448, 428451, B32B 2732, B32B 2734, B32B 2736
Patent
active
057703019
DESCRIPTION:
BRIEF SUMMARY
TECHNICAL FIELD
The present invention relates to a barrier composite film (gas barrier composite film) having improved gas barrier properties typically with respect to water vapor, oxygen gas and aroma or fragrance component and being, therefore, suitable for use as a film for preservation of a dried food, a film for the retort treatment or microwave heating of food or a packaging film for pharmaceutical products and precision electronic devices, films for production of a balloon or fly balloon, among other applications, and a method for producing the film.
BACKGROUND TECHNOLOGY
Coating of a base film with an extremely thin layer of an inorganic oxide insures remarkable improvement of barrier properties of the base film and hence provide a broader choice for the base film in relation with the heat resistance, mechanical characteristics or other properties. Further, it has been proposed formation of a synthetic resin layer on such inorganic oxide thin layer to impart heat-sealing properties to a barrier film or to protect an inorganic oxide thin layer.
By way of illustration, Japanese Patent Application Laid-open No. 27532/1985 (JP-A-60-27532) discloses a formation of a polymer layer on an inorganic oxide thin layer formed on a polyolefin film by dry-laminating or extrusion-laminating, and Japanese Patent Application Laid-open No. 237940/1988 (JP-A-63-237940) discloses a composite film comprising typically an indium oxide or tin oxide-sputtered film carrying a heat-sealing layer typically composed of an ethylene-propylene copolymer. Japanese Patent Application Laid-open No. 202435/1989 (JP-A-1-202435) and Japanese Patent Application Laid-open No. 202436/1989 (JP-A-1-202436) each discloses a packaging material for microwave cooker use or retort processing which comprises a base film supporting a vapor-deposited silicon oxide layer and either a heat-sealing layer or a protective layer, the heat-sealing layer comprising a heat-sealing resin film, typically a polypropylene film, as laminated, while the protective layer comprising a film as laminated or a thermosetting resin layer as coated. Japanese Patent Application Laid-open No. 297237/1989(JP-A-1-297237) discloses lamination of a film carrying an inorganic oxide thin layer with a biaxially oriented nylon film, and Japanese Patent Application Laid-open No. 86539/1992 (JP-A-3-86539) discloses laminating or coating of a film supporting an inorganic oxide thin layer with a vinylidene chloride-based resin, for example. Japanese Patent Application Laid-open No. 173137/1993 (JP-A-4-173137) proposes coating of a film supporting an inorganic oxide thin layer with a vinyl chloride-vinyl acetate copolymer, a polyamide, a polyester, an acrylic resin or others, or coating such film with a hot-melt coating composition.
However, when such polymer layer is formed on the barrier film by extrusion-lamination, a crack or defect is formed in the inorganic thin layer formed on the base film by heat and external mechanical forces due to lamination, so that barrier properties are extremely sacrificed. In the film as produced by dry-laminating a various film on the base film supporting the inorganic thin layer, the inorganic thin layer formed on the base film is apt to be destroyed on exposure to external mechanical forces in lamination of films or application of an adhesive agent. On the other hand, when a protective layer is coated on the inorganic thin layer on the base film by coating, barrier properties are not manifested by coating, and the inorganic thin layer is immediately fractured on exposure to external mechanical forces, so that barrier properties are remarkably deteriorated.
In these films including films as produced by laminating or coating the inorganic oxide thin layer supported on the base film with, for example, vinylidene chloride-based resin, the adhesive properties of the inorganic oxide thin layer with respect to the base film are low, and sufficiently high adhesive properties and excellent barrier properties can hardly be maintained or retained over a l
REFERENCES:
patent: 5100720 (1992-03-01), Sawada et al.
Miyake Ryuta
Murai Takaaki
Daicel Chemical Industries Ltd.
Nakarani D. S.
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