Stock material or miscellaneous articles – Layer or component removable to expose adhesive
Reexamination Certificate
2003-03-13
2004-11-23
Ahmad, Nasser (Department: 1772)
Stock material or miscellaneous articles
Layer or component removable to expose adhesive
C206S204000, C206S484000, C252S188100, C252S188280, C428S040200, C428S041300, C428S041500, C428S042200, C428S042300, C428S068000, C428S072000, C428S076000, C428S188000, C428S192000, C428S194000, C428S323000, C428S913000
Reexamination Certificate
active
06821594
ABSTRACT:
FIELD OF THE INVENTION
The present invention relates to an adhesively fixing oxygen-absorbing label, comprising an oxygen-absorbing sheet made of a resin composition blended with an oxygen-absorbing composition, and more particularly, to an oxygen-absorbing label having a water-resistant air-permeable layer for improving its water resistance required when applied to the preservation of foods.
RELATED ARTS
Conventionally, so-called oxygen-absorbing packages using oxygen absorbents have been widely used in order to realize oxygen-free packaging of oxygen-susceptible products such as foods and drugs, thereby maintaining good qualities thereof by preventing the deterioration in quality due to oxidation and the putrefaction due to breeding of microorganisms. Oxygen-absorbing packages are ordinary used in the form of an air-permeable small bag filled with granular or powdery oxygen absorbents. There have been recently developed an oxygen-absorbing sheet having an excellent oxygen removing capability which comprises, as an oxygen absorber, an oxygen-absorbing resin sheet produced by molding a thermoplastic resin blended with powdery oxygen absorbents such as iron powder-based oxygen absorbents into a sheet shape (Japanese Patent Application Laid-Open No. 2-72851).
The oxygen-absorbing sheet may be made into a multi-layer structure by covering an oxygen-absorbing sheet containing oxygen absorbents fixed in a thermoplastic resin with a film or sheet. The oxygen-absorbing sheet is suitably applied to an automatic labeling machine as compared to the small bag oxygen absorbents because the oxygen-absorbing sheet is free from leakage of the powdery oxygen absorbents due to rupture of the bag and can be made into a thin flat sheet with a uniform thickness. In view of the configuration and multi-layer structure of the oxygen-absorbing sheet, there have been proposed adhesive oxygen absorbers having a release adhesive layer on one surface of the oxygen-absorbing sheet. For example, Japanese Patent Application Laid-Open Nos. 7-219430 and 10-290915 propose oxygen-absorbing labels of laminated structures successively comprising a release layer, a base layer having a release adhesive layer, an oxygen-absorbing layer and an air-permeable layer in which the air-permeable layer is directly bonded to the base layer at portions surrounding an outer periphery of the oxygen-absorbing layer so as not to expose the oxygen-absorbing layer outside.
However, the conventional oxygen-absorbing labels containing iron as a main oxygen absorbent are usually provided at its surface contacting with products to be preserved with an air-permeable layer made of a porous material subjected to pore-forming procedure such as needle-perforation and stretching in order to ensure good oxygen absorbability by enhancing the air permeability. Therefore, when the oxygen-absorbing labels are used in packages for foods containing a large amount of water, the water enters into the inside of the oxygen-absorbing sheet through pores of the air-permeable layer under certain conditions, thereby causing undesired dissolution of the oxygen-absorbing components and rusts. The dissolved oxygen-absorbing components and rusts may ooze to the outer surface of the oxygen-absorbing label, resulting in deteriorated appearance of the packages.
In order to solve these problems, it is known that a non-porous film is used as the air-permeable layer to allow oxygen to permeate from the end surface of the film into the oxygen absorber, thereby preventing the rusts from oozing to the surface. However, in a water-requiring oxygen-absorbing sheet containing iron as a main oxygen absorbent, water inevitable for promoting the oxygen removal, together with oxygen, should be allowed to penetrate from the end surface, resulting in low oxygen-absorbing rate.
SUMMARY OF THE INVENTION
An object of the present invention is to provide an oxygen-absorbing label that is free from oozing of oxygen-absorbing components and rusts to the outer surface of the oxygen-absorbing label even when applied to foods containing a large amount of water.
As the result of extensive studies in view of the above object, the inventors have found that the above object can be achieved by an oxygen-absorbing label having, as an air-permeable layer, a laminated film comprising a water-resistant moisture-permeable resin film having a water pressure resistance of 2,000 mmH
2
O or higher and a moisture permeability of 1,000 g/m
2
/24 h or higher and a microporous film, without causing a substantial decrease in oxygen-absorbing rate. The present invention has been accomplished on the basis of this finding.
Thus, the present invention provides an oxygen-absorbing label exhibiting an improved water resistance, which has a laminated structure successively comprising a base layer having a release adhesive layer on its surface, an oxygen-absorbing sheet made from a oxygen-absorbing resin comprising a thermoplastic resin and an oxygen absorbent blended therein, and an air-permeable layer, wherein the air-permeable layer is bonded to the base layer at a portion surrounding an outer periphery of the oxygen-absorbing sheet, and the air-permeable layer comprises (A) a water-resistant moisture-permeable resin film having a water pressure resistance of 2,000 mmH
2
O or higher and a moisture permeability of 1,000 g/M
2
/24 h or higher and (B) a microporous film.
REFERENCES:
patent: 6139935 (2000-10-01), Cullen et al.
patent: 0657 277 (1995-06-01), None
patent: 0695 626 a1 (1996-02-01), None
patent: 4-1515555 (1992-05-01), None
EPO Search Report, dated Dec. 22, 2003, for EP 03 00 5557.
Nagata Masaki
Seki Takahiro
Watanabe Yuichi
Ahmad Nasser
Mitsubishi Gas Chemical Company Inc.
LandOfFree
Oxygen-absorbing label does not yet have a rating. At this time, there are no reviews or comments for this patent.
If you have personal experience with Oxygen-absorbing label, we encourage you to share that experience with our LandOfFree.com community. Your opinion is very important and Oxygen-absorbing label will most certainly appreciate the feedback.
Profile ID: LFUS-PAI-O-3321061