Fastener bag and fastener device

A fastener bag includes a packaging bag formed by heat-sealing side parts of a packaging sheet in a butt seam, and a fastening device attached to the inner surface of the packaging bag. The fastening device includes a male fastening member and a female fastening member. The male fastening member is disposed on one side of the heat-sealed butt seam of the packaging bag, and the female fastening member is disposed on the other side of the heat-sealed butt seam of the packaging bag so as to be engage with the male fastening member, and a tear-facilitating means is interposed between the male and the female fastening member. The fastener bag is capable of being opened and of being reclosed, and is suitable for use on an automatic filling and packaging machine.

This application is the national phase under 35 U.S.C. § 371 of PCT International Application No. PCT/JP00/06363 which has an International filing date of Sep. 18, 2000, which designated the United States of America.

TECHNICAL FIELD

The present invention relates to a fastener bag capable of being easily opened and reclosed, and of being applied to packaging an article therein by an automatic filling and packaging machine, and a fastening device.

BACKGROUND ART

Recently, most packaging bags are required to have both a capability to be easily opened and a capability to be reclosed. The field of automatic filling and packaging, in which operations for filling and packaging an article in a packaging bag are carried out simultaneously, requests a fastener bag having both a capability to be opened and a capability to be reclosed.

A known fastener bag having both a capability to be opened and a capability to be reclosed is made by superposing two packaging sheets, heat-sealing peripheral parts of the superposed packaging sheets, attaching the male fastening member of a fastening device to the inner surface of one of the packaging sheets, and attaching the female fastening member of the fastening device to the inner surface of the other packaging sheet. The male and the female fastening member are disengaged to open the fastener bag, and are reengaged to reclose the fastener bag.

A known easy-to-open fastener bag is formed from a packaging material having a property of facilitating opening the fastener bag, another packaging bag is provided with a notch, and a third known fastener bag is provided with a filament attached to its component sheet.

Although the foregoing fastener bag has both a capability to be opened easily and a capability to be reclosed, a bag making process of making the fastener bag, a filling and packaging process need complicated work because the fastener bag is made by superposing the two packaging sheets and heat-sealing the peripheral parts of the packaging sheets. Particularly, automatic filling and packaging needs a complicated apparatus, requires troublesome work, and have significant problems in practical work.

The present invention has been made in view of the foregoing problems and it is therefore an object of the present invention to provide a fastener bag having both a capability to be opened easily and a capability to be reclosed, and capable of being used for automatic filling on an automatic filling and packaging machine, and to provide a fastening device.

DISCLOSURE OF THE INVENTION

According to a first aspect of the present invention, a fastener bag includes a packaging bag formed by heat-sealing side parts of a packaging sheet in a butt seam; and a fastening device attached to the inner surface of the packaging bag; wherein the fastening device includes separate male and female fastening members, the male fastening member is disposed on one side of the heat-sealed butt seam of the packaging bag, the female fastening member is disposed on the other side of the heat-sealed butt seam of the packaging bag so as to be engage with the male fastening member, and a tear-facilitating means is extended between the male and the female fastening member.

According to a second aspect of the present invention, a fastener bag includes a packaging bag formed by heat-sealing side parts of a packaging sheet in a butt seam; and a fastening device attached to a part of the inner surface of the packaging bag on one side of the heat-sealed butt seam; wherein the fastening device includes separate male and female fastening members, the male and the female fastening member are disposed with a space therebetween so as to be engaged, and a tear-facilitating means is interposed between the male and the female fastening member.

According to a third aspect of the present invention, a fastener bag includes a packaging bag formed by heat-sealing side parts of a packaging sheet in a butt seam; and a fastening device attached to the inner surface of the packaging bag; wherein the fastening device is an integral molding including a male fastening member, a female fastening member and a connecting member, and a tear-facilitating means is combined with the connecting member.

According to a fourth aspect of the present invention, a fastener bag includes a packaging bag formed by heat-sealing side parts of a packaging sheet in an envelope seam; and a fastening device attached to the inner surface of the packaging bag; wherein the fastening device is an integral molding including a male fastening member, a female fastening member and a connecting member, and a tear-facilitating means is combined with the connecting member.

According to a fifth aspect of the present invention, a fastener bag includes a packaging bag formed by heat-sealing side parts of a packaging sheet in a butt seam; and a fastening device attached to the inner surface of the packaging bag; wherein the fastening device includes separate male and female fastening members, the male fastening member is disposed on one side of the heat-sealed butt seam of the packaging bag, the female fastening member is disposed on the other side of the heat-sealed butt seam so as to engage with the male fastening member, and a cut tape is extended from one to the other end of the packaging bag on a part of the inner surface of the packaging bag between the male and the female fastening member, and is attached to the inner surface of the packaging bag.

According to a sixth aspect of the present invention, a fastener bag includes a packaging bag formed by heat-sealing side parts of a packaging sheet in a butt seam; and a fastening device attached to a part of the inner surface of the packaging bag on one side of the heat-sealed butt seam; wherein the fastening device includes separate male and female fastening members, the male and the female fastening member are disposed with a space therebetween so as to be engaged, and a cut tape is extended from one to the other end of the packaging bag on a part of the inner surface of the packaging bag between the male and the female fastening member, and is attached to the inner surface of the packaging bag.

According to a seventh aspect of the present invention, a fastener bag includes a packaging bag formed by heat-sealing side parts of a packaging sheet in an envelope seam; and a fastening device attached to the inner surface of the packaging bag; wherein the fastening device includes male and female fastening members, the male fastening member is disposed on one side of the heat-sealed envelope seam of the packaging bag, the female fastening member is disposed on the other side of the heat-sealed envelope seam of the packaging bag so as to be engaged with the male fastening member, and a cut tape is extended from one to the other end of the packaging bag on a part of the inner surface of the packaging bag between the male and the female fastening member, and is attached to the inner surface of the packaging bag.

According to an eighth aspect of the present invention, a fastening device includes separate male and female fastening members, wherein a linear member is combined with the male or the female fastening member.

BEST MODE FOR CARRYING OUT THE INVENTION

Referring toFIG. 1, a fastener bag1in a first embodiment according to the present invention includes a packaging bag2, and a fastening device3welded or bonded to the inner surface of the packaging bag2.

As shown inFIGS. 1 and 2, the packaging bag2is formed by folding side parts4aand4bof a rectangular packaging sheet, joining the folded side parts4aand4bsuch that the inner surfaces thereof are contiguous, heat-sealing the thus joined folded side parts4aand4bto form a tubular structure having a back sealed part5, and heat-sealing the upper and the lower end of the tubular structure to form an upper sealed part6and a lower sealed part7.

Although it is preferably that the packaging sheet is a laminated film, the packaging sheet may be a single film.

Laminated films suitable as the packaging sheet for forming a transparent packaging bag2are a laminated film formed by laminating a 20 to 50 μm thick biaxially oriented polypropylene film, and a 20 to 60 μm thick nonoriented polypropylene film by a laminating process using a 2 to 3 μm thick dry bonding layer, a laminated film formed by laminating a 9 to 25 μm thick polyester film, and a 25 to 120 μm thick straight-chain, low-density polyethylene film by a laminating process using a 2 to 3 μm thick dry bonding layer, and a laminated film formed by laminating a 9 to 20 μm thick biaxial oriented nylon film, and a 25 to 120 μm thick polyethylene film by a laminating process using a 2 to 3 μm thick dry bonding layer. An extruded 12 to 20 μm thick polyethylene layer may be used as a bonding layer instead of the dry bonding layer.

Laminated films suitable as the packaging sheet for forming an opaque packaging bag2are a laminated film formed by laminating a 9 to 25 μm thick polyester film, a 6 to 30 μm thick aluminum foil, and a 20 to 120 μm thick straight-chain low-density polyethylene film by a laminating process using a 2 to 3 μm thick dry bonding layer, and a laminated film formed by laminating a 9 to 25 μm thick polyester film, a 12 μm thick aluminum-metallized polyester film, and a 20 to 60 μm thick nonoriented polypropylene film by a laminating process using a 2 to 3 μm thick dry bonding layer. A 12 to 20 μm thick extruded polyethylene layer may be used as a bonding layer instead of the dry bonding layer.

Referring toFIG. 2, the fastening device3includes a separate male fastening member8and a separate female fastening member9. The male fastening member8has a base part8aattached to a part of the inner surface of the packaging bag2on one side of the back sealed part5. The female fastening member9has a base part9aattached to a part of the inner surface of the packaging bag2on the other side of the back sealed part5.

The male fastening member8and the female fastening member9are formed by extruding an olefin resin, such as a polyethylene, a polypropylene or a copolymer of a polyethylene and a polypropylene by an extrusion molding machine. Although the male fastening member8and the female fastening member9shown inFIG. 2have each a single engaging part, the same may be provided with two or more engaging parts when necessary.

As shown inFIG. 2, the packaging bag2is provided with narrow roughened tear parts10in the outer surface of the laminated film forming the packaging bag2. The narrow roughened tear parts10are formed along the back sealed part5. The roughened tear parts10are those provided with scratches not penetrating the laminated film formed by pressing a sand paper against the laminated film. The roughened tear parts10are the tear-facilitating means of the packaging bag.

When opening the fastener bag1, one end of the back sealed part5is held between fingers, the back sealed part5is pulled away from the surface of the fastener bag1to tear the laminated film along bends in the back sealed part provided with the roughened tear parts10.

A method of manufacturing the fastener bag will be described.

A continuous laminated film is cut in a packaging sheet of a length equal to twice the sum of the width of the packaging bag2shown inFIG. 1and the length of the back sealed part5of the packaging bag2to form the packaging bag2that can be used on an automatic filling and packaging machine. When folding the packaging sheet to form the packaging bag2, at least one of the side parts4aand4bjoined by heat-sealing to form the back sealed part5is provided with the roughened tear part10. Preferably, both the side parts are provided with the roughened tear parts, respectively.

The side parts4aand4bare bent and are joined such that the inner surfaces thereof are contiguous to form a tubular structure. The roughened tear parts10formed in the packaging sheet extend along the bends of the side parts4aand4b.

Then, a continuous fastening device3with the male fastening member8and the female fastening member9engaged is inserted in the tubular structure such that the base part8aof the male fastening member8is disposed on a part of the inner surface of the tubular structure on one side of the joint of the side parts4aand4b, and the base part9aof the female fastening member9of the fastening device is disposed on a part of the inner surface of the tubular structure on the other side of the joint of the side parts4aand4b. Thus, the male fastening member8and the female fastening member9are disposed on the opposite sides of the joint of the side parts4aand4b, respectively.

Then, the joined side parts4aand4bof the tubular structure are bonded together by heat-sealing and, at the same time, the respective base parts8aand9aof the male fastening member8and the female fastening member9are welded or bonded to the inner surface of the tubular structure. Thus, the tubular structure having open opposite ends and provided with the fastening device3attached to its inner surface is formed.

Then, one end of the tubular structure fixedly provided with the fastening device3and having the opposite open ends is heat-sealed to form the lower heat-sealed part7. Thus, the packaging bag2having an open upper end is obtained. An article is filled through the open upper end in the packaging bag2, and then the upper end of the packaging bag2is heat-sealed to form the upper heat-sealed part6. The packaging bag2filled with the article is cut along the upper heat-sealed part6to separate the packaging bag2from the packaging sheet.

FIGS. 3 and 4show a fastener bag lain a second embodiment according to the present invention. The fastener bag1ashown inFIGS. 3 and 4differs from the fastener bag1shown inFIGS. 1 and 2in that the fastener bag1ais provided with a tear strip11as a tear-facilitating means combined with a fastening device3ainstead of the roughened tear parts10of the fastener bag1shown inFIGS. 1 and 2.

Referring toFIG. 4, the fastening device3aincludes a separate male fastening member8and a separate female fastening member9. The tear strip11is attached temporarily to the inner surface of the base part of the male fastening member8by welding or bonding. The tear strip11may be attached temporarily to the outer surface of the base part8aof the male fastening member8. When the tear strip11is attached to the outer surface of the base part8a, the respective positions of the male fastening member8and the female fastening member9on a packaging bag2are interchanged.

Although it is preferable that the tear strip11is made of a polymer different from that forming the packaging sheet and is, for example, a nylon monofilament or a metal wire, the tear strip11may be a cotton yarn or a silk yarn, provided that the tear strip11has a strength sufficient to tear both the base part8aof the male fastening member8and the packaging sheet.

The male fastening member8and the female fastening member9of the fastening device3aare formed by continuously extruding an olefin resin by an extrusion molding machine. The tear strip11can be combined with the male fastening member8or the female fastening member9by forming the tear strip11simultaneously with the male fastening member8or the female fastening member9by coextrusion.

As shown inFIG. 3, the fastening device3aand the tear strip11are extended continuously between the upper and the lower end of the fastener bag1a. A triangular pull tab13is formed by cutting lines12in a lower heat-sealed part7at a position corresponding to the tear strip11and an end of the tear strip11is connected to the pull tab13.

When opening the fastener bag1a, the lower heat-sealed part7is cut along the cutting lines12to separate the pull tab13from the lower heat-sealed part7, and then the pull tab13is held between fingers and is pulled away from the fastener bag1a. Consequently, the tear strip11connected to the pull tab13cuts both the base part8aof the male fastening member8and the packaging sheet to open the fastener bag1a.

Whereas the fastener bag1ashown inFIG. 4has the butt seam type packaging bag2a, a fastener bag1bshown inFIG. 5has an envelope seam type packaging bag2b.

The envelope seam type packaging bag2bhas an envelope seam5aformed by superposing and joining together side parts of a packaging sheet. Laminated films suitable as the packaging sheet for forming the packaging bag2bare a laminated film formed by laminating a 20 to 60 μm thick nonoriented polypropylene film, a 20 to 50 μm thick biaxially oriented polypropylene film, and a 20 to 60 μm thick nonoriented polypropylene film by a laminating process using a 2 to 3 μm thick dry bonding layer, a laminated film formed by laminating a 30 to 50 μm thick straight-chain low-density polyethylene film, a 9 to 25 μm thick polyester film, and a 25 to 120 μm thick straight-chain, low-density polyethylene film by a laminating process using a 2 to 3 μm thick dry bonding layer, and a laminated film formed by laminating a 25 to 60 μm thick polyethylene film, a 9 to 20 μm thick biaxial oriented nylon film, and a 25 to 120 μm thick polyethylene film by a laminating process using a 2 to 3 μm thick dry bonding layer. An extruded polyethylene layer may be used as a bonding layer instead of the dry bonding layer.

A fastening device3cincluded in a fastener bag1cshown inFIG. 6is different in construction from that included in the fastener bag1bshown inFIG. 5. The fastening device1cshown inFIG. 6is a molding integrally having a male fastening member8, a female fastening member9, and a connecting part14interconnecting the male fastening member8and the female fastening member9. A tear strip11, i.e., a tear-facilitating means, is attached to the inner surface of the connecting part14.

The fastening device3cand the tear strip11of the fastener bag1c, similarly to the fastening device3aand the tear strip11shown inFIG. 2, are extended between the upper and the lower end of a packaging bag2, a triangular pull tab is formed by cutting lines in a lower heat-sealed part and an end of the tear strip11is connected to the pull tab.

A fastener bag1dshown inFIG. 7differs from the fastener bag1shown inFIG. 2in that a fastening device3is extended on the inner surface of a packaging bag2along a butt seam5on one side of the butt seam5, a ridge12extending along the fastening device3is formed in a part of the packaging bag2between a base part8aof a mal fastening member8, and a base part9aof a female fastening member9, and roughened tear parts10a, i.e., tear-facilitating means, are formed at the root of the ridge12.

A fastener bag1eshown inFIG. 8is not provided with any part corresponding to the ridge12of the packaging bag2of the fastener bag1dshown inFIG. 7, and is provided with a fastening device3ainstead of the fastening device3. In the fastener bag1eshown inFIG. 8, a part of the packaging bag2between a base part8aof a male fastening member8, and a base part9aof a female fastening member9is cut with a tear strip11. Although the fastener bag1eshown inFIG. 8employs the tear strip11as a cutting means for cutting the packaging bag2, the tear strip11may be omitted, and a tape may be welded or bonded to a part of the inner surface of the packaging bag2between the base part8aof the male fastening member, and the base part9aof the female fastening member9or a narrow roughened tear part may be formed near the respective base parts8aand9aof the male fastening member8and the female fastening member9, and a cut tape or the narrow roughened tear part may be torn to open the packaging bag2.

The cut tape is formed from, for example, a laminated film formed by sandwiching a 12 μm thick polyester film between 30 μm thick polyethylene films. The cut tape is formed in a width slightly smaller than the distance between the respective base parts8aand9aof the male fastening member8and the female fastening member9so that the cut tape is guided by the base part8aof the male fastening member8or the base part9aof the female fastening member9when cutting the packaging bag2with the cut tape.

Whereas the fastener bag1eshown inFIG. 8has the butt seam type packaging bag2, a fastener bag if shown inFIG. 9has an envelope seam type packaging bag2b.

A fastener bag1gshown inFIG. 10is provided with a cut tape100as a tear-facilitating means instead of the roughened tear part10of the fastener bag1shown in FIG.2.

The cut tape100of the fastener bag1gis attached to a part of the inner surface of a packaging bag2bbetween a base part8aof a male fastening member8and a back sealed part5formed in the packaging bag2g. The cut tape100serves as a tear-facilitating means for opening the packaging bag2g. Two longitudinal cutting lines may be formed in the cut tape100, and a part between the two cutting lines of the cut tape may be used as a tear-facilitating means.

The cut tape100has a width in the range of 3 to 15 mm. The cut tape100is extended continuously between an upper heat-sealed part6and a lower heat-sealed part7of the packaging bag1gon a part of the packaging bag2gbetween the male fastening member8and the female fastening member9. A triangular pull tab is formed in at least either the upper heat-sealed part6or the lower heat-sealed part7by cutting lines. The cutting line separates a part of the heat-sealed part to form the pull tab integrally with the cut tape100at one end of the cut tape100.

As shown inFIG. 11, the cut tape100is a three-layer structure consisting of a straight-chain low-density polyethylene layer101, a polyester layer102, and an easy-to-peel layer103. The easy-to-peel layer103is formed of a chlorinated polyethylene or an EVA, or is a hot-melt layer. The easy-to-peel layer103has a peeling strength on the order of 200 g/cm.

A packaging sheet forming the packaging bag2ghas a breaking strength higher than the peeling strength of the easy-to-peel layer103of the cut tape100.

The cut tape10may be a four-layer structure consisting of a low-density polyethylene layer, a polyester layer, a low-density polyethylene layer and an easy-to-peel layer, a four-layer structure consisting of a straight-chain low-density polyethylene layer, a polyester layer, a straight-chain low-density polyethylene layer and an easy-to-peel layer, a four-layer structure consisting of a very-low-density polyethylene layer, a polyester layer, a very-low-density polyethylene layer and an easy-to-peel layer or a four-layer structure consisting of a cast polypropylene layer, a polyester layer, a cast polypropylene layer and an easy-to-peel layer.

A method of manufacturing the fastener bag1gwill be described.

A continuous laminated film is cut in a packaging sheet of a length equal to twice the sum of the width of the packaging bag2gshown inFIG. 10and the length of the back sealed part5of the packaging bag2gto form the packaging bag2gthat can be used on an automatic filling and packaging machine.

Side parts4aand4bare bent and are joined such that the inner surfaces thereof are contiguous to form a tubular structure. Then, a continuous fastening device3with the male fastening member8and the female fastening member9engaged and the cut tape100are inserted in the tubular structure.

The male fastening member8and the female fastening member9are disposed on the opposite sides, respectively, of the joint of the side parts4aand4b. The cut tape100is extended continuously between the upper and the lower end of the tubular structure on a part between the base part8aof the male fastening member8and the base part9aof the female fastening member9of the tubular structure.

Then, the joined side parts4aand4bof the tubular structure are bonded together by heat-sealing to form the back sealed part5and, at the same time, the respective base parts8aand9aof the male fastening member8and the female fastening member9are welded or bonded to the inner surface of the tubular structure. Thus, the tubular structure having open opposite ends and provided with the fastening device3and the cut tape100attached to its inner surface is formed. The easy-to-peel layer103of the cut tape100is bonded to the base part9aof the female fastening member9.

Then, one end of the tubular structure fixedly provided with the fastening device3and the cut tape100, and having the opposite open ends is heat-sealed to form a lower heat-sealed part7. Thus, the packaging bag2ghaving an open upper end is obtained. An article is filled through the open upper end in the packaging bag2g, and then the upper end of the packaging bag2gis heat-sealed to form the upper heat-sealed part6. The packaging bag2gfilled with the article is cut along the upper heat-sealed part6to separate the packaging bag2gfrom the packaging sheet.

When opening the fastener bag1gto take out the contents, the upper heat-sealed part6or the lower heat-sealed part7is cut along the cutting lines to form a tab separated from the heat-sealed part.

Then, the tab is held between fingers and is pulled away from the surface of the fastener bag1gto cut a part of the packaging bag2gbetween the respective base parts8aand9aof the male fastening member8and the female fastening member9with the cut tape100. Consequently, the fastener bag1gis opened and the contents can be taken out of the fastener bag1gthrough an opening formed by cutting the packaging bag2gwith the cutting tape100.

The remnant contents remaining in the fastener bag1gafter taking out some of the contents can be sealed in the fastener bag1gby engaging the male fastening member8and the female fastening member9.

A fastener bag1hin a preferred embodiment of the present invention shown inFIG. 12has a packaging bag2hidentical with the packaging bag2gof the fastener bag1gshown inFIG. 10. The fastener bag1hdiffers in the position of its fastening device3afrom the fastener bag1gshown inFIG. 10.

In the fastener bag1h, both the male fastening member8and the female fastening member9of the fastening device3aare disposed on the inner surface of the packaging bag2gshown inFIG. 10on one side of the back sealed part5.

A part of the fastener bag1hapart from the back sealed part5is cut to open the fastener bag1h.

A jip bag1jin a preferred embodiment according to the present invention shown inFIG. 13is identical in the position of its fastening device3with the fastener bag1gshown inFIG. 10. Where as the packaging bag2gof the fastener bag1gis of a butt seam type, the packaging bag2jof the fastener bag1jis of an envelope seam type.

INDUSTRIAL APPLICABILITY

The fastener bag according to the present invention has the packaging bag formed by processing a single packaging sheet, the fastening device is disposed on one of the walls of the packaging bag, and the tear-facilitating means is placed on the inner surface of the packaging bag or the fastening device. Thus, the fastener bag can be opened and reclosed and can be used on an ordinary automatic filling and packaging machine without requiring any special devices.

The fastener bag according to the present invention has the packaging bag formed by processing a single packaging sheet, the fastening device is disposed on one of the walls of the packaging bag, and the cut tape is attached to the inner surface of the packaging bag. Thus, the fastener bag can be opened and reclosed and can be used on an ordinary automatic filling and packaging machine without requiring any special devices.