Easily unsealable packaging body and method of manufacturing the same
An easy-open packaging body 1 includes: a container body 10 with a flange 14 formed on a circumference of an opening 13 , and a cover 20 heat-sealed to the flange 14 to close the opening 13 . Inner and outer notches 15 A and 15 B enclosing the opening 13 are formed respectively on inner and outer circumferential sides on the flange 14 . The flange 14 and the cover 20 are heat-sealed by a first seal part 16 A having a predetermined width and formed between the inner and outer notches 15 A and 15 B to enclose the opening 13 and a second seal part 16 B having a width narrower than that of the first seal part 16 A and formed within an area of the first seal part 16 A to enclose the opening 13 along the first seal part 16 A, the second seal part 16 B having a projected seal part 17 projected outward relative to the other part on a position corresponding to a tab 21.
1. A sealed container, comprising:
a container body molded from a multilayer sheet; and
a cover heat sealed to the container body;
wherein:
the container body comprises a receptacle for holding contents having an opening, and a flange provided at a circumference of the opening and extending radially outward from the opening;
the cover comprises a tab extending radially outward from a remainder of the cover;
an innermost layer of the multilayer sheet forming the container body forms an interior surface of the receptacle and an upper surface of the flange;
the flange comprises an inner notch and an outer notch;
the inner notch extends around the circumference of the opening and protrudes at least partially through the innermost layer of the container body;
the outer notch extends around the circumference of the opening and protrudes at least partially through the innermost layer of the container body;
the inner notch is closer to the opening of the container body than the outer notch;
a section of the innermost layer of the container body provided on the flange between the inner notch and the outer notch is adhered to the cover;
the section of the innermost layer is adhered to the cover by:
placing the cover in contact with the upper surface of the flange;
pressing a first heat seal ring onto the flange via the cover in the section between the inner notch and the outer notch and removing the first heat seal ring; and
pressing a second heat seal ring onto the flange via the cover in the section between the inner notch and the outer notch and removing the second heat seal ring;
wherein:
the second heat seal ring has a narrower profile than the first heat seal ring;
the second heat seal ring comprises a projected part extending radially outwardly from a remainder of the second heat seal ring;
the second heat seal ring is pressed onto a portion of the flange wholly within a portion of the flange onto which the first heat seal ring was previously pressed; and
the projected part of the second heat seal is located in a vicinity of the tab of the cover when the second heat seal ring is pressed onto the flange; and
when the cover is removed from the container body by pulling the tab, at least a portion of the section of the innermost layer of the container body provided on the flange between the inner notch and the outer notch is removed from the container body with the cover.
2. The sealed container of claim 1 , wherein the innermost layer of the multilayer sheet comprises polypropylene.
3. The sealed container of claim 1 , wherein the flange comprises a bent part formed by bending an outer circumferential end of the flange.
4. The sealed container of claim 1 , wherein the second heat seal ring is pressed onto the flange at a temperature and a pressure that exceed a temperature and a pressure at which the first heat seal ring is pressed onto the flange.
5. The sealed container of claim 1 , wherein the second heat seal ring is pressed onto the flange at a temperature that exceeds a temperature at which the first heat seal ring is pressed onto the flange by 5° C. or more.
6. A method for preparing a sealed container, comprising:
filling a container body molded from a multilayer sheet with contents;
placing a cover on the container body;
performing a first heat sealing step to adhere the cover to the container body; and
performing a second heat sealing step to adhere the cover to the container body after the first heat sealing step is complete;
wherein:
the container body comprises a receptacle for holding the contents having an opening, and a flange provided at a circumference of the opening and extending radially outward from the opening;
the cover comprises a tab extending radially outward from a remainder of the cover;
an innermost layer of the multilayer sheet forming the container body forms an interior surface of the receptacle and an upper surface of the flange;
the flange comprises an inner notch and an outer notch;
the inner notch extends around the circumference of the opening and protrudes at least partially through the innermost layer of the container body;
the outer notch extends around the circumference of the opening and protrudes at least partially through the innermost layer of the container body;
the inner notch is closer to the opening of the container body than the outer notch;
performing the first heat sealing step comprises pressing a first heat seal ring onto the flange via the cover in a section of the innermost layer of the container body provided on the flange between the inner notch and the outer notch and removing the first heat seal ring;
performing the second heat sealing step comprises pressing a second heat seal ring onto the flange via the cover in the area between the inner notch and the outer notch and removing the second heat seal ring;
the second heat seal ring has a narrower profile than the first heat seal ring;
the second heat seal ring comprises a projected part extending radially outwardly from a remainder of the second heat seal ring;
the second heat seal ring is pressed onto a portion of the flange wholly within a portion of the flange onto which the first heat seal ring was previously pressed; and
the projected part of the second heat seal is located in a vicinity of the tab of the cover when the second heat seal ring is pressed onto the flange.
7. The method of claim 6 , wherein the innermost layer of the multilayer sheet comprises polypropylene.
8. The method of claim 6 , wherein the flange comprises a bent part formed by bending an outer circumferential end of the flange.
9. The method of claim 6 , wherein the second heat seal ring is pressed onto the flange at a temperature and a pressure that exceed a temperature and a pressure at which the first heat seal ring is pressed onto the flange.
10. The method of claim 6 , wherein the second heat seal ring is pressed onto the flange at a temperature that exceeds a temperature at which the first heat seal ring is pressed onto the flange by 5° C. or more.
11. A sealed container, comprising:
a container body molded from a multilayer sheet; and
a cover heat sealed to the container body;
wherein:
the container body comprises a receptacle for holding contents having an opening, and a flange provided at a circumference of the opening and extending radially outward from the opening;
the cover comprises a tab extending radially outward from a remainder of the cover;
an innermost layer of the multilayer sheet forming the container body forms an interior surface of the receptacle and an upper surface of the flange;
the flange comprises an inner notch and an outer notch;
the inner notch extends around the circumference of the opening and protrudes at least partially through the innermost layer of the container body;
the outer notch extends around the circumference of the opening and protrudes at least partially through the innermost layer of the container body;
the inner notch is closer to the opening of the container body than the outer notch;
a section of the innermost layer of the container body provided on the flange between the inner notch and the outer notch is adhered to the cover;
the section of the innermost layer includes a first portion having a first thickness and an a second portion having a second thickness;
the second thickness is smaller than the first thickness;
the second portion has a narrower profile than the first portion;
the second portion includes a projected part extending radially outwardly from a remainder of the second portion;
the second portion is wholly within the first portion;
the projected part of the second portion is located in a vicinity of the tab of the cover; and
when the cover is removed from the container body by pulling the tab, at least a portion of the section of the innermost layer of the container body provided on the flange between the inner notch and the outer notch is removed from the container body with the cover.
12. The sealed container of claim 11 , wherein the innermost layer of the multilayer sheet comprises polypropylene.
13. The sealed container of claim 11 , wherein the flange comprises a bent part formed by bending an outer circumferential end of the flange.