Packaging bag and method for manufacturing same

A method for manufacturing a packaging bag, comprising the steps of:

• (a) continuously feeding a single strip of plastic film material for a main bag body in a longitudinal direction, said single strip having opposite half portions between which a longitudinal central line of said single strip exists;
• (b) continuously feeding a pair of strips of thin sheet material for a framework member to place said pair of strips for the framework member on a surface of said single strip for the main bag body in predetermined positions of the respective opposite half portions of the single strip;
• (c) bonding said pair of strips for the framework member to said single strip for the main bag body in respective opposite half portions thereof;
• (d) folding said single strip for the main bag body with said pair of strips for the framework member in two along said longitudinal central line of said single strip for the main bag body to bring one of said opposite half portions of said single strip for the main bag body close to another of said opposite half portions to prepare a folded composite strip so that said pair of strips for the framework member are placed in an inside of said folded composite strip;
• (e) thermally bonding said folded composite strip in a perpendicular direction to a longitudinal direction thereof by predetermined intervals to form heat-sealed portions;
• and
• (f) cutting each of said heat-sealed portions in two in said perpendicular direction to the longitudinal direction of said folded composite strip,
• thereby continuously manufacturing a plurality of packaging bags each of which comprises the main bag body and the framework member, which is foldable/unfoldable together with said main bag body, to enable said framework member and said main bag body to be shifted between a generally flat collapsed state and an expanded state.

A method for manufacturing a packaging bag, comprising the steps of:

• (a) continuously feeding a pair of strips of plastic film material for a main bag body in a longitudinal direction so as to be apart from each other;
• (b) continuously feeding a pair of strips of thin sheet material for a framework member to place said pair of strips for the framework member on respective inner surfaces of said pair of strips for the main bag body in predetermined positions thereof;
• (c) bonding said pair of strips for the framework member to said pair of strips for the main bag body, respectively;
• (d) bringing one of said pair of strips for the main bag body close to another of said pair of strips for the main bag body so as to cause said pair of strips for the framework member face each other, thus preparing a set of composite strips;
• (e) thermally bonding said set of composite strips in a perpendicular direction to a longitudinal direction thereof by predetermined intervals to form side heat-sealed portions;
• (f) thermally bonding said set of composite strips on one of longitudinal edges of said set of composite strips to form a bottom heat-sealed portion;
• and
• (g) cutting each of said side heat-sealed portions in two in said perpendicular direction to the longitudinal direction of said set of composite strips,
• thereby continuously manufacturing a plurality of packaging bags each of which comprises the main bag body and the framework member, which is foldable/unfoldable together with said main bag body, to enable said framework member and said main bag body to be shifted between a generally flat collapsed state and an expanded state.

A method for manufacturing a packaging bag, comprising the steps of:

• (a) preparing a single piece of plastic film material for a main bag body, said single piece having opposite half portions between which a central line of said single piece exists;
• (b) placing a pair of pieces of thin sheet material for a framework member on a surface of said single piece for the main bag body in predetermined positions of respective opposite half portions of the single piece;
• (c) bonding said pair of pieces for the framework member to said single piece for the main bag body in respective opposite half portions thereof;
• (d) folding said single piece for the main bag body with said pair of pieces for the framework member in two along said central line of said single piece for the main bag body to bring one of said opposite half portions of said single piece for the main bag body close to another of said opposite half portions to prepare a folded composite piece so that said pair of pieces for the framework member are placed in an inside of said folded composite piece;
• and
• (e) thermally bonding said folded composite piece on opposite sides thereof to form heat-sealed portions,
• thereby manufacturing the packaging bag, which comprises the main bag body and the framework member, which is foldable/unfoldable together with said main bag body, to enable said framework member and said main bag body to be shifted between a generally flat collapsed state and an expanded state.

A method for manufacturing a packaging bag, comprising the steps of:

• (a) placing a pair of pieces of plastic film material for a main bag body so as to be apart from each other;
• (b) placing a pair of pieces of thin sheet material for a framework member on respective inner surfaces of said pair of pieces for the main bag body in predetermined positions thereof;
• (c) bonding said pair of pieces for the framework member to said pair of pieces for the main bag body, respectively;
• (d) bringing one of said pair of pieces for the main bag body close to another of said pair of pieces for the main bag body so as to cause said pair of pieces for the framework face each other, thus preparing a set of composite pieces;
• and
• (e) thermally bonding said set of composite pieces at opposite side edges and a bottom edge thereof to form side heat-sealed portions and a bottom heat-sealed portion;
• thereby manufacturing the packaging bags, which comprises the main bag body and the framework member, which is foldable/unfoldable together with said main bag body, to enable said framework member and said main bag body to be shifted between a generally flat collapsed state and an expanded state.

A method for manufacturing a packaging bag, comprising the steps of:

• (a) placing a pair of pieces of plastic film material for a main bag body so as to be apart from each other;
• (b) placing a framework member, which is formed into a sleeve, on respective inner surfaces of said pair of pieces for the main bag body in predetermined positions thereof;
• (c) bonding said framework member to said pair of pieces for the main bag body, respectively;
• (d) bringing one of said pair of pieces for the main bag body close to another of said pair of pieces for the main bag body so as to receive said framework member between said pair of pieces for the main bag body, thus preparing a set of composite pieces;
• and
• (e) thermally bonding said set of composite pieces at opposite side edges and a bottom edge thereof to form side heat-sealed portions and a bottom heat-sealed portion;
• thereby manufacturing the packaging bags, which comprises the main bag body and the framework member, which is foldable/unfoldable together with said main bag body, to enable said framework member and said main bag body to be shifted between a generally flat collapsed state and an expanded state.