NONWOVEN FABRIC BAG WITH HANDLES

A nonwoven fabric bag includes: a bag body; and a pair of handles. A fabric sheet is folded in two. A bottom of the bag is formed by a sheet portion including the fold line. Side edges of the opposing folded halves of the sheet are bonded together on right and left sides to form a bag. A sheet portion along a peripheral edge of an opening of the bag is folded inward and bonded to form a double-layer portion, thereby forming the bag body. Two strips are attached to the double-layer portion, thereby forming the pair of handles. The side edges are bonded by impulse heat sealing. The peripheral edge of the opening and a vicinity thereof, and a part connecting to the fold line are sewn. The double-layer portion is bonded by discontinuous ultrasonic sealing. Attachment portions between the double-layer portion and the handles are sewn.

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Description
DETAILED DESCRIPTION OF THE INVENTION

1. Technical Field

The present invention relates to nonwoven fabric bags with handles. More particularly, the present invention relates to nonwoven fabric bags with handles that can be manufactured with reduced labor and cost for manufacturing, and that are less likely to break even if a bulky or heavy item is placed therein.

2. Related Art

Conventionally, paper bags or cloth bags with handles are used to carry items. In particular, since women often carry small bags such as handbags, they often use paper bags or cloth bags with handles so they can carry items to a place they are going or items that they get while they are out.

The paper bags with handles are convenient for portable use because they are light and become thin when folded. However, since they are not strong and have a fixed shape, they are not suitable for carrying heavy or bulky items. On the other hand, the cloth bags with handles are strong, and their shape can change according to the shape of the item placed therein. Accordingly, the cloth bags with handles are suitable for carrying bulky or heavy items, but the bags themselves are heavy and are not foldable into a small size. The cloth bags with handles are therefore not convenient for portable use. Moreover, the cloth bags are more expensive than the paper bags, etc., which makes people less willing to buy the cloth bags just for temporary use.

Accordingly, in recent years, bags with handles have been desired which can be easily used for temporary use, which do not easily break, whose shape can be easily changed, and which are light and foldable into a compact shape for portable use.

On the other hand, nonwoven fabric shopping bags have been proposed as a substitute for shopping bags made of a polyolefin film, specifically so-called plastic bags that are used when checking out at a supermarket etc. (Patent Document 1). However, nonwoven fabric bags with handles have not been proposed which are satisfactory for use as a substitute for the paper bags or cloth bags with handles.

RELATED ART DOCUMENT Patent Document

  • [Patent Document 1] Japanese Patent Application Publication No. 2009-172283

DISCLOSURE OF THE INVENTION Problem to be Solved by the Invention

The shopping bag described in Patent Document 1 is manufactured by bonding polyolefin nonwoven fabric by heat sealing.

The shopping bag described in Patent Document 1 can be repeatedly used even if a large or heavy item is placed therein, is light and compact, and is easy to recycle. Accordingly, this shopping bag is very useful as compared to the conventional shopping bags made of a polyolefin film such as plastic bags.

However, nonwoven fabric bags with handles which are often carried when going out are expected to be used much more times than the above shopping bag, and therefore higher durability and strength are required for such nonwoven fabric bags.

Accordingly, a desired nonwoven fabric bag with handles may not be able to be manufactured by merely bonding nonwoven fabric by heat sealing as in the above shopping bag. The reason for this is as follows. Heat sealing bonding is to bond nonwoven fabric by melting and pressing it, so the bonded portion becomes thin and easily breaks. For example, when the bag is opened, the bag is subjected to a force that opens up the heat seal portion on the side surface of the bag. As a result, the bag with handles may rip like tearing from the opening of the bag. If a heavy item is placed in the bag, the handles may be delaminated from the bonded portion of the bag body, and the handles may come off from the bag body. If a heavy item is placed in the bag, the bottom portion formed by bonding the bottom of the bag by heat sealing or the side surface portions of the bag body which connect to the bottom of the bag are subjected to a load due to the weight applied to the bottom of the bag. Thus, the bag may tear from these portions.

One possible solution to the above problem is to bond the heat seal portion by sewing having higher strength than the heat sealing. However, since nonwoven fabric bags formed by sewing fabrics are manufactured by manually sewing nonwoven fabric sheets with a sewing machine etc., it requires labor and time to manufacture such nonwoven fabric bags, thereby increasing manufacturing cost. The sewn nonwoven fabric bags are therefore more expensive than the paper bags, which makes people less willing to buy the cloth bags just for temporary use.

Accordingly, nonwoven fabric bags are desired which can reduce labor and time required for manufacturing and thus can reduce cost as compared to nonwoven fabric bags finished entirely by sewing, which can carry bulkier or heavier items as compared to nonwoven fabric bags manufactured by heat sealing, and which are inexpensive and strong so that the bags can be easily used for temporary usage.

The present invention was developed in view of the above situations, and it is an object of the present invention to provide a nonwoven fabric bag with handles that reduces labor and time required for manufacturing to reduce manufacturing cost, and that has sufficient strength.

Means for Solving the Problem

The inventors studied hard to solve the above problem, and found that a nonwoven fabric bag having sufficient strength was obtained by merely bonding a nonwoven fabric sheet by using impulse heat sealing as heat sealing and combining the heat seal in part with ultrasonic sealing, and partially sewing and reinforcing a peripheral edge of an opening in a side edge and its vicinity and a portion connecting to a fold line of the nonwoven fabric sheet forming a bottom of the bag, and both edges in the longitudinal direction of the handles and attachment portions of the handles, and found that the bag is produced by merely partially sewing specific parts, and thus labor and time required for manufacturing can be reduced, and manufacturing cost can be reduced. The inventors thus completed the invention.

That is, the present invention relates to the following:

(1) A nonwoven fabric bag with handles, comprising: a bag body; and a pair of handles, wherein a nonwoven fabric sheet having a generally line-symmetrical shape is folded in two along a line of symmetry, a bottom of the bag is formed by a sheet portion including the fold line, side edges of the opposing folded halves of the nonwoven fabric sheet are bonded together on both right and left sides to form a bag, a sheet portion along a peripheral edge of an opening of the bag is folded inward and bonded to form a double-layer portion, thereby forming the bag body, and two strips, each sewn to have a double-layer structure, are attached to the double-layer portion, thereby forming the pair of handles, the side edges are bonded by impulse heat sealing, of the heat seal portion, the peripheral edge of the opening and a vicinity thereof, and a part connecting to the fold line are sewn, the double-layer portion is bonded by discontinuous ultrasonic sealing, and attachment portions between the double-layer portion and the handles are sewn.

(2) The nonwoven fabric bag with handles according to (1), wherein the bag body and the pair of handles are made of polypropylene nonwoven fabric, and a thread used in the parts sewn to have the double-layer structure and in the sewn parts is a polyester spun or polypropylene thread.

(3) The nonwoven fabric bag with handles according to (2), wherein the bonded portion by the impulse heat sealing is formed by sandwiching two polypropylene nonwoven fabric sheets, placed on top of each other, between a pair of cylindrical heaters from both sides in a vertical direction, and heating the polypropylene nonwoven fabric sheets, and in the heating process, a portion sandwiched by the pair of cylindrical heaters and thermally fused is pushed toward both right and left sides of the heaters so as to form a thick thermally welded portion.

(4) The nonwoven fabric bag with handles according to (1) to (3), wherein the bonded portion by the impulse heat sealing is formed by sandwiching two nonwoven fabric sheets, placed on top of each other, between a pair of cylindrical heaters having a diameter of 0.5 to 1.5 mm from both sides in a vertical direction, and heating the nonwoven fabric sheets.

(5) The nonwoven fabric bag with handles according to (4), wherein the heating by supplying power to the pair of cylindrical heaters is performed at an instantaneous current of 40 to 50 A and an instantaneous voltage of 180 to 260 V and for heating time of 3 to 5 seconds.

Effects of the Invention

The nonwoven fabric bag with handles according to the present invention is manufactured by merely bonding a nonwoven fabric sheet by using impulse heat sealing as heat sealing and combining the heat seal in part with ultrasonic sealing, and partially sewing specific parts. Thus, labor and time required for manufacturing can be reduced and manufacturing cost can be reduced, as compared to conventional sewn nonwoven fabric bags with handles.

Moreover, the nonwoven fabric bag with handles according to the present invention does not easily break because the parts that can easily break due to ripping, tearing, etc. by placing a bulky or heavy item in the bag, namely the peripheral edge of the opening and its vicinity in the side edge, the portion of the side edge connecting to the fold line of the nonwoven fabric sheet forming the bottom of the bag, and both edges extending in the longitudinal direction of the handles and the handle attachment portions, are sewn and reinforced.

Since the peripheral edge of the opening is bent inward, and is discontinuously bonded by ultrasonic sealing, the bag does not easily break even if an item is repeatedly placed into and taken out of the bag.

Moreover, the handles and the peripheral edge of the opening are not easily stretched because two nonwoven fabrics are placed on top of each other in the handles and the peripheral edge of the opening, which tend to be easily stretched by a force applied thereto.

Thus, the nonwoven fabric bag with handles according to the present invention can have large allowable capacity and load limit for items.

In the case where the nonwoven fabric bag with handles is manufactured by using only polypropylene nonwoven fabric and polypropylene thread as materials, the nonwoven fabric can be easily collected for recycling, whereby environmental protection and resource saving can be expected.

The nonwoven fabric bag with handles according to the present invention is light and can be folded into a compact shape, and can be easily unfolded to be used as a shopping bag. The nonwoven fabric bag with handles has high portability as well as paper bags.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is a perspective view of a nonwoven fabric bag with handles manufactured according to a first embodiment.

FIG. 2(a) is a front view of the nonwoven fabric bag with handles with a folded bottom manufactured according to the first embodiment, and FIG. 2(b) is an A-A′ sectional view of FIG. 2(a).

FIG. 3 is a perspective view of a nonwoven fabric bag with handles manufactured according to a second embodiment.

FIG. 4 is a perspective view of the nonwoven fabric bag with handles with folded sides manufactured according to the second embodiment.

FIG. 5 shows schematic diagrams illustrating one form of impulse heat sealing.

 MODES FOR CARRYING OUT THE INVENTION

The present invention will be described in more detail.

A nonwoven fabric bag with handles according to the present invention comprises: a bag body; and a pair of handles, wherein a nonwoven fabric sheet having a generally line-symmetrical shape is folded in two along a line of symmetry, a bottom of the bag is formed by a sheet portion including the fold line, side edges of the opposing folded halves of the nonwoven fabric sheet are bonded together on both right and left sides to form a bag, a sheet portion along a peripheral edge of an opening of the bag is folded inward and bonded to form a double-layer portion, thereby forming the bag body, and two strips, each sewn to have a double-layer structure, are attached to the double-layer portion, thereby forming the pair of handles.

The nonwoven fabric sheet that is used in the nonwoven fabric bag with handles according to the present invention may be any nonwoven fabric having high strength, high formability, and high bonding property (adhesion property) of heat sealing etc., and conventionally known nonwoven fabric can be used. For example, it is preferable, in terms of environmental protection and resource saving, to use a thread made of the same recyclable material as the nonwoven fabric sheet to sew a double-layer portion of a nonwoven fabric sheet or to sew a nonwoven fabric sheet, because used bags can be collected for recycling. For example, nonwoven fabric and thread may be made of polyolefin such as polyethylene or polypropylene, or polyester such as polyethylene terephthalate. Specifically, a polyester spun thread or a polypropylene thread may be used. It is particularly preferable to use polypropylene nonwoven fabric and a polypropylene thread.

The nonwoven fabric sheet used in the nonwoven fabric bag with handles of the present invention may be colorless, bleached, or colored by a common dyeing method such as beam dyeing, jet dyeing, jigger dyeing, and dipping dyeing, or may be a nonwoven fabric sheet having a logo or character printed thereon with ink. It is preferable in terms of environmental protection and resource saving to use a nonwoven fabric sheet having a logo or character printed thereon by using decolorable ink or using a method of forming an ink layer on the bag body surface with, e.g., a polymer region highly soluble in warm water interposed therebetween, because such a nonwoven fabric sheet can be easily recycled.

The nonwoven fabric sheet used in the nonwoven fabric bag with handles of the present invention may have any shape as long as the nonwoven fabric sheet can be folded in two, and as necessary, the bottom of the bag can be formed by a sheet portion including the fold line, and the side edges of the bag can be bonded together. For example, the nonwoven fabric sheet preferably has a bilaterally symmetrical shape such as a rectangle so that the side edges overlap each other when the nonwoven fabric sheet is folded in two. The nonwoven fabric sheet may not have a bilaterally symmetrical shape. In this case, the side edges of the bag may be formed by simultaneously bonding and fusion-cutting the overlapping portions of the sheet by impulse heat sealing.

A conventionally known method can be used to fold the nonwoven fabric sheet to form the bottom of the bag. Examples of such a method includes a method of valley-folding a sheet portion including the fold line inward, a method of folding the nonwoven fabric sheet after making a cut therein or after cutting off a part of the nonwoven fabric sheet.

In the nonwoven fabric bag with handles of the present invention, impulse heat sealing is used to bond the side edges, and ultrasonic sealing is used to bond the peripheral edge of the opening to form the double-layer structure.

Impulse heat sealing, hot air heat sealing, hot plate heat sealing, iron heat sealing, etc. are known as heat sealing methods, and impulse heat sealing is used in the present invention. The impulse heat sealing has a simple mechanism and can be easily controlled, and nonwoven fabrics can be bonded by merely heating for a short time only during processing in the impulse heat sealing. The impulse heat sealing is therefore preferable as it can be performed at low cost.

The impulse heat sealing is preferably performed by bonding two nonwoven fabrics by using a pair of cylindrical heaters, as shown in, e.g., FIG. 5.

That is, as shown in FIG. 5(a), two nonwoven fabrics 31 are placed on top of each other, and sandwiched in the vertical direction by a pair of cylindrical heaters 32 (FIG. 5(b)), and power is supplied to heat the heaters 32. Thus, a thermally welded portion 33 is formed. As the thermally welded portion 33 is sandwiched by the heaters 32, the portion sandwiched by the pair of cylindrical heaters and thermally fused is pushed toward both right and left sides of the two heaters 32.

Accordingly, the resultant thermally welded portion 33 is thick at the bonded portion of the two nonwoven fabrics 31 (FIG. 5(c)). This improves strength against breakage, and breakage is less likely to occur from the heat sealed portion. Heat seal is thus obtained which is much less likely to break than heat seal formed by, e.g., hot plate heat sealing.

For the impulse heat sealing, a preferable diameter of each cylinder of the pair of cylindrical heaters is 0.5 to 1.5 mm, a preferable instantaneous current is 40 to 50 A, a preferable voltage is 180 to 260 V, and preferable heating time is 3 to 5 seconds.

The side edges of the bag need to be bonded by impulse heat sealing continuously along the entire length. However, in ultrasonic sealing that is used to form the double-layer portion of the peripheral edge of the opening, at least two portions, namely the peripheral edge of the opening and the end of the nonwoven fabric folded inward, are bonded by discontinuous ultrasonic sealing in a knurling pattern etc. along the perimeter of the bag body. That is, the peripheral edge of the opening has bonded portions and non-bonded portions. Since the non-bonded portions can easily move, it is easy to open up the opening, and the shape of the bag can change according to the item that is placed therein. Accordingly, even a bulk item can be carried.

In the case where the peripheral edge of the opening is heat sealed continuously along the entire perimeter, the bag may tend to break when a heavy item is placed therein, because the thickness of the nonwoven fabric sheet is small in the heat seal portion. In the present invention, however, since the peripheral edge of the opening is discontinuously bonded by ultrasonic sealing, the peripheral edge of the opening has parts that have not been subjected to the ultrasonic sealing, namely parts having a thickness corresponding to the thickness of two nonwoven fabrics. Accordingly, the bag does not easily break even if a heavy item is placed therein. In such a double-layer portion of the peripheral edge of the opening, a reinforcing piece made of plastic, paper, cloth, or the like can be interposed between the nonwoven fabrics. In this case, using the reinforcing piece made of the same material as that of the nonwoven fabric and the string can eliminate the need to separate the reinforcing piece for recycling etc.

For the ultrasonic heat sealing, a preferable current is 0.8 to 1.5 A, a preferable voltage is 180 to 260 V, and a preferable processing rate is 3 to 5 m/minute.

The bag body of the nonwoven fabric bag with handles of the present invention is formed by sewing, in each of the side edges bonded by impulse heat sealing, the peripheral edge of the opening and its vicinity, and the part connecting to the fold line of the sheet portion.

Conventional sewn bag bodies have many sewn parts, and if any of those parts fails to be firmly sewn to their ends, the bag bodies break from such a part. Accordingly, the conventional bag bodies need to be manually sewn one by one with a sewing machine. On the other hand, according to the bag body of the present invention, the peripheral edge of the opening and the side edges of the bag, where there usually are many parts to be sewn, are bonded by impulse heat sealing, and only those four parts on the side edges of the bag which are described above need to be sewn. Thus, many bag bodies can be manufactured by a smaller number of people. This can reduce manufacturing cost per bag.

It is preferable in terms of strength and work efficiency that each part of the side edges which is to be sewn be a straight part with a length of about 1 to 2 cm. It is preferable to sew such a part by using a combination of straight stitch and zigzag stitch with a width of 1 to 2 mm with respect to the sewing direction.

It is preferable to use a polyester spun or polypropylene thread for sewing.

When a bulky or heavy item is placed in nonwoven fabric bags, the bag body is expanded and the nonwoven fabric bag is subjected to a force to open up the bonded portion. Accordingly, in the bag body bonded merely by heat sealing, each side edge of the bag is intensively subjected to a force in the peripheral edge of the opening and the vicinity thereof, and in the parts connecting to the fold line of the sheet portion forming the bottom of the bag, and the bag rips or tears from any of those parts. However, in the nonwoven fabric bag of the present invention, those parts which are intensively subjected to a force are not only bonded by impulse heat sealing but also sewn. This can prevent ripping or tearing of the bag even if a force is intensively applied to those parts. That is, the nonwoven fabric bag is durable and can be repeatedly used.

Moreover, since the peripheral edge of the opening is bonded discontinuously, the non-bonded parts are extended to reduce the force that is applied to the bonded parts of the peripheral edge of the opening in each side edge of the bag, even if a higher load is applied thereto. The nonwoven fabric bag is therefore less likely to break.

Such discontinuous bonding is implemented by, e.g., providing ultrasonic seal portions with a length of about 2 to 5 mm parallel to each other at regular intervals. It is preferable to provide about three to five ultrasonic seal portions per centimeter.

Since the peripheral edge of the opening is opened up when placing an item in or take it out of the bag, the fabric is stretched or rubbed. Accordingly, in the case of sewn nonwoven fabric bags, the sewn parts of the peripheral edge of the opening come apart, spoiling the appearance. However, the bag body of the present invention has resistance to tension and is less likely to be stretched, because the sheet is folded inward along the peripheral edge of the opening and bonded by ultrasonic sealing. Moreover, since the peripheral edge of the opening forms a fold line, the peripheral edge of the opening is less likely to fray or tear as compared to the case where the peripheral edge of the opening is a cut end face of nonwoven fabric.

The handles of the present invention are formed by folding two nonwoven fabric sheets each in two, sewing both longitudinal edges of the resultant two double-layer strips together, and sewing the two double-layer strips to the double-layer portion of the bag body.

The shape of the handles can be adjusted as appropriate according to the usage and size of the nonwoven fabric bag. The length of the handles may be adjusted so that the handle portions can be held with a hand or can be placed on an arm or shoulder, or the width of the handle portions can be adjusted so that it is easy to hold them.

When a heavy item is placed in nonwoven fabric bags with handles, the handles or the portions of the handles which are attached to the bag body are subjected to a large force, whereby the handles tend to be stretched or the attachment portions of the handles tend to rip or tear. However, the nonwoven fabric bag with handles of the present invention are less likely to be stretched because the handles are formed by folding a nonwoven fabric in two and sewing the resultant double-layer structure of the nonwoven fabric. Moreover, since the handles are also attached to the bag body by sewing, the nonwoven fabric bag with handles of the present invention has much higher strength and is less likely to break, as compared to bonding by heat sealing

Attachment of the handles only needs to be performed by firmly sewing the handles to the double-layer portion of the upper part of the bag body, and can be selected as appropriate according to the size or usage of the bag. For example, tensile strength in the lateral and vertical directions is increased by sewing the handles to the double-layer portion with a substantially square seam, and the strength is significantly increased by further sewing diagonal seams in the substantially square seam.

The handles may be attached to either the inside or outside of the opening. The bags having the handles attached to the inside of the opening can be more easily stored and shipped. Moreover, the handles can be folded and held in the bag when the bag is folded to carry, and therefore the handles are not obstructive.

EMBODIMENTS

The present invention will be described in more detail with reference to the accompanying drawings. FIGS. 1 and 2 are diagrams showing a nonwoven fabric bag with handles according to a first embodiment of the present invention, and FIGS. 3 and 4 are diagrams showing a nonwoven fabric bag with handles according to a second embodiment. However, the nonwoven fabric bag with handles according to the present invention is not limited to the following embodiments.

First Embodiment

A nonwoven fabric bag 1 with handles of the first embodiment includes a bag body 2 and handles 3 which are made of polypropylene nonwoven fabric and a polypropylene thread (see FIG. 1), and a bottom 4 of the bag is foldable (see FIG. 2).

A 76 cm by 112 cm rectangular nonwoven fabric sheet was folded in two so that the shorter sides of the folded halves faced each other, the sheet including a fold line 7 was valley-folded inward by 7.5 cm, and side edges 8 of the bag were bonded by impulse heat sealing (basic conditions: heaters (pair of cylindrical heaters, diameter of each cylinder: 0.9 mm), heating (sealing) time: 4 sec., voltage: 220 V, and instantaneous current: 45 A).

The bag body 2 has a perimeter of 76 cm and a height of 45 cm, and the bottom 4 of the bag has a substantially elliptical shape with a shorter diameter of 15 cm and a longer diameter of 30 cm. The sheet of the peripheral edge of the opening was folded inward by 3.5 cm, and the folded portion was sealed at two positions, namely 0.5 cm and 3.0 cm from the peripheral edge of the opening, by ultrasound sealing 5 (basic conditions: voltage: 220 V, current: 1 A, and speed: 4 m/min.) in a knurling pattern having a width of 3 mm and an interval of 2 mm, thereby forming a double-layer portion 6.

In each side edge 8 of the bag, the peripheral edge of the opening and its vicinity 8a, and a part 8b connecting to the fold line 7 included in the sheet forming the bottom 4 of the bag were sewn along the length of 1.5 cm.

The handles 3 were produced as follows. A nonwoven fabric sheet having a width of 5 cm and a length of 45 cm was folded in two so that the longer sides faced each other, and both edges 9 extending in the longitudinal direction were sewn to form strips having a width of 2.5 cm and a length of 45 cm. These strips were sewn to the double-layer portion 6 of the bag body 2 in a substantially square seam 10 of 2 cm by 2 cm.

Second Embodiment

A nonwoven fabric bag 21 with handles according to a second embodiment includes a bag body 22 and handles 23 which are made of polypropylene nonwoven fabric and a polypropylene thread (see FIG. 3), and the sides of the bag are foldable (see FIG. 4).

A 76 cm by 112 cm rectangular nonwoven fabric sheet was folded in two so that the shorter sides of the folded halves faced each other, and the sheet including a fold line 27 was valley-folded inward by 7 cm. After the sheet was cut, and side edges 28 of the bag were bonded by impulse heat sealing (basic conditions: heaters (pair of cylindrical heaters, diameter of each cylinder: 0.9 mm), heating (sealing) time: 4 sec., voltage: 220 V, and instantaneous current: 45 A).

The bag body 22 has a width of 22 cm on its front and rear surfaces, a width of 14 cm on its right and left side surfaces, a height of 45 cm, and the bottom 24 of the bag has a substantially rectangular shape. The sheet of the peripheral edge of the opening was folded inward by 3.5 cm, and the folded portion was sealed at two positions, namely 0.5 cm and 3.0 cm from the peripheral edge of the opening, by ultrasound sealing 25 (basic conditions: voltage: 220 V, current: 1 A, and speed: 4 m/min.) in a knurling pattern having a width of 3 mm and an interval of 2 mm, thereby forming a double-layer portion 26.

In each side edge 28 of the bag, the peripheral edge of the opening and its vicinity 28a, and a part 28b connecting to the fold line 27 included in the sheet forming the bottom 26 of the bag were sewn along the length of 1.5 cm.

The handles 23 were produced as follows. A nonwoven fabric sheet having a width of 5 cm and a length of 45 cm was folded in two so that the longer sides face each other, and both edges 29 extending in the longitudinal direction were sewn to form strips having a width of 2.5 cm and a length of 45 cm. These strips were sewn to the double-layer portion 26 of the bag body 22 in a substantially square seam 30 of 2 cm by 2 cm, having diagonal seams.

The side edges 8, 28 of the nonwoven fabric bags 1, 21 with handles were pulled by a force P1 as shown by arrows in FIGS. 1 and 3. As a result, the nonwoven fabric bags 1, 21 with handles didn't rip.

The handles of the nonwoven fabric bags 1, 21 with handles were held by a hand and the bottoms 4, 24 were pressed from inside of the bag body. As a result, the handles of the nonwoven fabric bags 1, 21 with handles were firmly held on the bag bodies.

Then, the center of the peripheral edge of the opening of the bag body and the corners of the bottom closer to the side edges of the nonwoven fabric bags 1, 21 with handles (joint portions with the fold line) were held and pulled. As a result, the nonwoven fabric bags 1, 21 with handles didn't rip.

From the above results, since the regions that tend to rip, come off, etc. are reinforced by sewing, the nonwoven fabric bag with handles according to the present invention does not rip or come off even if a bulky or heavy item is placed in the bag.

In the nonwoven fabric bags 1, 21 with handles having the above configuration, the amount of sewing is smaller, the side edges whose processing normally requires a lot of time and labor can be bonded in a simple manner by impulse heat sealing in a short time, and the peripheral edge of the opening is bonded in a simple manner by discontinuous ultrasonic sealing in a short time, as compared to the conventional sewn nonwoven fabric bags. This can reduce labor and manufacturing time required for mass production of the bags, and can reduce manufacturing cost. Moreover, in the nonwoven fabric bags 1, 21 with handles of the present invention, the bonded portions of the side edges of the bag and the attachment portions of the handles do not rip or tear even if a bulky or heavy item is placed in the bag.

In the case where the nonwoven fabric bag with handles of the present invention is made only of recyclable polyolefin nonwoven fabric and polyolefin thread, the nonwoven fabric bag with handles can be collected to reproduce polyolefin nonwoven fabric or polyolefin thread, whereby, e.g., the nonwoven fabric bag with handles of the present invention can be reproduced. This can reduce generation of carbon dioxide by incineration of the discarded nonwoven fabric bag with handles, and waste of resources, which is extremely preferable in terms of environmental protection and resource saving.

The nonwoven fabric bags 1, 21 with handles of the present invention are made of light polypropylene nonwoven fabric, and the portion other than the handles and the peripheral edge of the opening is made of a single sheet of light fabric. Thus, the nonwoven fabric bags 1, 21 with handles of the present invention can be folded into a compact shape and can be easily carried, and can be unfolded to use as a nonwoven fabric bag with handles. The nonwoven fabric bags 1, 21 with handles of the present invention are highly suitable for portable use.

FIRST TEST EXAMPLE

As described above, in the first and second embodiments, impulse heat sealing and ultrasonic sealing using specific conditions were used to bond polypropylene nonwoven fabric. Testing was conducted to examine the level of seal strength (tensile strength) that can be achieved by these sealing methods as compared to polypropylene nonwoven fabrics bonded by commonly used heat sealing conditions (hot plate heat sealing, basic conditions: temperature setting: 200° C., time: 1 sec.)

Test Method:

Two polypropylene nonwoven fabrics having a length of 100 mm and a width of 25 mm were prepared, and these nonwoven fabrics were placed on top of each other. One 25 mm side was bonded by hot plate heat sealing, ultrasonic heat sealing (the same conditions as in the first and second embodiments), and impulse heat sealing (the same conditions as in the first and second embodiments), and the seal strength (tensile strength) (N/15 mm) of each sample was measured.

The above operation was repeated twenty times and an average value was calculated.

The result is shown in Table 1.

TABLE 1 Seal Strength of Each Seal (N/15 mm) Type of Sealing Hot Plate Heat Sealing Ultrasonic Sealing Impulse Heat Sealing Basic Measured Basic Measured Basic Measured Conditions No. Value Conditions No. Value Conditions No. Value Temperature 1 1.1 Voltage: 1 30.3 Heater 1 71.3 Setting: 2 0.4 220 V 2 36.1 Diameter: 2 53.4 200° C. 3 2.2 Current: 3 37.2 0.9 mm 3 55.6 Time: 1 sec. 4 1.2 1 A 4 22.6 Time: 4 sec. 4 54.8 5 1.3 Speed: 5 26 Voltage: 5 63.2 6 1.1 4 m/min. 6 33.6 220 V 6 59.2 7 1 7 27.9 Instantaneous 7 49.8 8 0.9 8 29.4 Current: 45 A 8 59.4 9 2 9 34.7 9 50.1 10 1 10 38 10 49.8 11 1.7 11 20.9 11 49.6 12 0.8 12 35.2 12 55.4 13 1.2 13 24.2 13 66.4 14 1.2 14 33.8 14 48.9 15 1 15 34.1 15 63.8 16 1.1 16 31.8 16 72.3 17 2.1 17 23.3 17 52 18 1.4 18 35.2 18 59.5 19 1.2 19 27.4 19 60.9 20 1.1 20 37.3 20 45.5 Average 1.25 Average 30.95 Average 57.04

As can be seen from Table 1, the polypropylene nonwoven fabrics bonded by impulse heat sealing exhibited much higher seal strengths (tensile strengths) (N/15 mm) as compared to the polypropylene nonwoven fabrics bonded by ultrasonic sealing or hot plate sealing. This result shows that the impulse heat sealing can be preferably used as bonding means in the bonding portion of the bag body which is subjected to a stress by the load of the item contained in the bag, and particularly in the side edges of the bag which are subjected to a stress that opens up the bonded portion when a bulky or heavy item is placed in the bag body and the bag body is stretched and expanded.

DESCRIPTION OF THE REFERENCE NUMERALS

  • 1, 21 Nonwoven Fabric Bag
  • 2, 22 Bag Body
  • 3, 23 Handle
  • 4, 24 Bottom
  • 5, 25 Discontinuous Bonding by Ultrasonic Sealing
  • 6, 26 Double-Layer Portion
  • 7, 27 Fold Line Included in Nonwoven Fabric Sheet Forming Bottom
  • 8, 28 Side Edge (Bonded Portion by Impulse Heat Sealing)
  • 8a, 28a Peripheral Edge of Opening of Side Edge and Its Vicinity (Sewn Part)
  • 8b, 28b Portion of Side Edge Connecting to Fold Line (Sewn Part)
  • 9, 29 Both Edges Extending in Longitudinal Direction of Handles (Sewn Part)
  • 10, 30 Handle Attachment Portion (Sewn Part)
  • 31 Nonwoven Fabric
  • 32 Heater (Cylindrical)
  • 33 Thermally Welded Portion

Claims

1. A nonwoven fabric bag with handles, comprising:

a bag body; and
a pair of handles, wherein
a nonwoven fabric sheet having a generally line-symmetrical shape is folded in two along a line of symmetry,
a bottom of the bag is formed by a sheet portion including the fold line,
side edges of the opposing folded halves of the nonwoven fabric sheet are bonded together on both right and left sides to form a bag,
a sheet portion along a peripheral edge of an opening of the bag is folded inward and bonded to form a double-layer portion, thereby forming the bag body, and
two strips, each sewn to have a double-layer structure, are attached to the double-layer portion, thereby forming the pair of handles,
the side edges are bonded by impulse heat sealing,
of the heat seal portion, the peripheral edge of the opening and a vicinity thereof, and a part connecting to the fold line are sewn,
the double-layer portion is bonded by discontinuous ultrasonic sealing, and
attachment portions between the double-layer portion and the handles are sewn.

2. The nonwoven fabric bag with handles according to claim 1, wherein

the bag body and the pair of handles are made of polypropylene nonwoven fabric, and a thread used in the parts sewn to have the double-layer structure and in the sewn parts is a polyester spun or polypropylene thread.

3. The nonwoven fabric bag with handles according to claim 2, wherein

the bonded portion by the impulse heat sealing is formed by sandwiching two polypropylene nonwoven fabric sheets, placed on top of each other, between a pair of cylindrical heaters from both sides in a vertical direction, and heating the polypropylene nonwoven fabric sheets, and in the heating process, a portion sandwiched by the pair of cylindrical heaters and thermally fused is pushed toward both right and left sides of the heaters so as to form a thick thermally welded portion.

4. The nonwoven fabric bag with handles according to claim 1, wherein

the bonded portion by the impulse heat sealing is formed by sandwiching two nonwoven fabric sheets, placed on top of each other, between a pair of cylindrical heaters having a diameter of 0.5 to 1.5 mm from both sides in a vertical direction, and heating the nonwoven fabric sheets.

5. The nonwoven fabric bag with handles according to claim 4, wherein

the heating by supplying power to the pair of cylindrical heaters is performed at an instantaneous current of 40 to 50 A and an instantaneous voltage of 180 to 260 V, and for heating time of 3 to 5 seconds.

6. The nonwoven fabric bag with handles according to claim 2, wherein

the bonded portion by the impulse heat sealing is formed by sandwiching two nonwoven fabric sheets, placed on top of each other, between a pair of cylindrical heaters having a diameter of 0.5 to 1.5 mm from both sides in a vertical direction, and heating the nonwoven fabric sheets.

7. The nonwoven fabric bag with handles according to claim 3, wherein

the bonded portion by the impulse heat sealing is formed by sandwiching two nonwoven fabric sheets, placed on top of each other, between a pair of cylindrical heaters having a diameter of 0.5 to 1.5 mm from both sides in a vertical direction, and heating the nonwoven fabric sheets.

8. The nonwoven fabric bag with handles according to claim 6, wherein the heating by supplying power to the pair of cylindrical heaters is performed at an instantaneous current of 40 to 50 A and an instantaneous voltage of 180 to 260 V, and for heating time of 3 to 5 seconds.

9. The nonwoven fabric bag with handles according to claim 7, wherein the heating by supplying power to the pair of cylindrical heaters is performed at an instantaneous current of 40 to 50 A and an instantaneous voltage of 180 to 260 V, and for heating time of 3 to 5 seconds.

Patent History
Publication number: 20140023296
Type: Application
Filed: Jul 17, 2013
Publication Date: Jan 23, 2014
Inventor: Fukuichi MIWA (Tokyo)
Application Number: 13/944,310
Classifications
Current U.S. Class: Additional Layer Of Material At Element Attachment Location (383/20)
International Classification: B65D 33/06 (20060101);