CA1218036A - Easy-to-open synthetic resin bag and apparatus for the manufacture thereof - Google Patents
Easy-to-open synthetic resin bag and apparatus for the manufacture thereofInfo
- Publication number
- CA1218036A CA1218036A CA000421922A CA421922A CA1218036A CA 1218036 A CA1218036 A CA 1218036A CA 000421922 A CA000421922 A CA 000421922A CA 421922 A CA421922 A CA 421922A CA 1218036 A CA1218036 A CA 1218036A
- Authority
- CA
- Canada
- Prior art keywords
- bag
- opening
- tear string
- notches
- string
- Prior art date
- Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
- Expired
Links
- 239000000057 synthetic resin Substances 0.000 title claims abstract description 24
- 229920003002 synthetic resin Polymers 0.000 title claims description 23
- 238000004519 manufacturing process Methods 0.000 title abstract description 10
- 229920005989 resin Polymers 0.000 claims abstract description 5
- 239000011347 resin Substances 0.000 claims abstract description 5
- 239000007767 bonding agent Substances 0.000 claims description 5
- 238000010030 laminating Methods 0.000 abstract description 5
- 230000000875 corresponding effect Effects 0.000 abstract 2
- 239000002985 plastic film Substances 0.000 description 8
- 229920006255 plastic film Polymers 0.000 description 8
- 230000002093 peripheral effect Effects 0.000 description 5
- 238000007789 sealing Methods 0.000 description 5
- 238000005520 cutting process Methods 0.000 description 4
- 238000000034 method Methods 0.000 description 3
- 239000000463 material Substances 0.000 description 2
- 229920000136 polysorbate Polymers 0.000 description 2
- 230000008569 process Effects 0.000 description 2
- 238000005452 bending Methods 0.000 description 1
- 230000000694 effects Effects 0.000 description 1
- 239000000835 fiber Substances 0.000 description 1
- 239000002184 metal Substances 0.000 description 1
- 238000012216 screening Methods 0.000 description 1
- 238000003466 welding Methods 0.000 description 1
Landscapes
- Bag Frames (AREA)
Abstract
Abstract of the Disclosure The invention rerates to an easy-to-open syn-thetic resin bag comprising: a bag body constituted by a laminated film formed by laminating several layers of snythetic resin film; a tear string bonded to part of an inner surface of the bag body corre-sponding to the opening thereof; and a tab formed at an end of the tear string; whereby pulling the tear string by the tab enables one side surface of the bag to be torn open, thereby allowing the bag to be opened. Also disclosed is a bag manufacturing apparatus capable of automatically bonding the tear string to the part of the inner surface of the bag body corresponding to the opening thereof when the bag body is being formed by employing the laminated film of the above kind.
Description
The present invention relates to an easy--to-open synthetic resin bag and apparatus for the manufacture thereof.
In a conven-tional bag having a bag body consti--tuted by placing two laminated films formed by laminating together several layers of synthetic resin film over each other and heat-sealing -the peripheral edges thereof, when part of the bag body is opened in order to remove -the con-tents, since the hag body is constitu-ted by laminated films, the bag body is difficul-t to tear and hence the opening pro-cess is difficult.
According to the present invention there is pro-vided an easy-to-open synthetic resin bag comprising: a) a bag body made of a pair of opposed walls, each wall formed from a plurality of layers of synthetic resin film, said walls being sealed together by hea-t around -the periphery thereof to form a seal.ed border region around an unbonded interior of the bag, b) a tear string heat-fused -to -the in-side surface of one of said walls through -the entire length thereof, said tear string having an outer surface thereof concentrically covered with a heat sealable resin, said tear string extending along a line corresponding to a transverse opening to be formed in said bag, said tear string having one end extending into said border region and fused in said bor-der region between said two walls~ c) a pair of straight notches symmetrically disposed at both sides of said -tear string, said notches having outer ends terminating at -the outer-most end of said bag body and inner ends thereof terminating in said border region at a location spaced out-wardly of -the unfused interior of said bag, d) an opening formed in said border region extending transverse to the length of said tear string and be-tween -the inside of said bag and the inner ends of said notches such that said tear string passes through -the width of said opening, said open-ing being adjacent to, but sl.igh-tly spaced from said inner - 1 - ~i~
.~ ;
1L~ 3~
ends of said notches, said opening defining a pulliny tab in said border eg:ion together with said notches, said open-~i~ ing having a length transverse ~to said tear string far ~`1 greater than the distance between inner end sof said notches, said opening having an inner convergent edge closest to the interior of said bag and disposed on said tear string, said s inner convergen-t edge makine an angle '~ of less -than 90 1 with said tear string measured from the opening edge toward ~ the interior of said body.
The present invention thus provides an easy-to-open synthetic resin bag comprising: a bag body cons-ti.-tuted by a laminated film formed by laminating synthetic resin films; a tear string bonded to part of the inner surface of the bag body corresponding to the opening thereof; and a tab formed over an end of the -tear string, whereby pulling the tear s-tring by -the -tab enables the side surface to which the tear string is bonded -to be easily and surely torn, thereby allowing the bag body -to be easily and speedily opened. The invention also provides -to a bag-manufacturing apparatus capable of continuously bonding the -tear string with tabs provided at the ends thereof -to the inner surfaces of the bag bodies in -the bag body manufac-turing process.
The present invention will be further illus-tra-ted by way of the accompanying drawings, in which:-,~ ., Figure l is a front elevation of an easy-to-open synthetic resin bag in accordance wi~h a preferred embodiment of the invention;
Figure 2 is a section -taken along the line I-I
of Fig. l;
Figure 3 is a section taken along the line II-II
of Fig. l;
Figure 4 illustrates a transverse groove foxmed in a tab part of the bag body of the easy~to-open synthetic resin bag of Fig. l;
Figures 5 through 9 illustrate other examples of the transverse groove shown in Fig. 4;
Figure lO is a perspective view of the easy-to-open synthetic resin bag of Fig. l in which the tear string thereof is being pulled;
Figure ll illustra-tes the tab;
Figure 12 is a perspective view of a bag body of an easy-to-open synthetic resin bag in accordance with another preferred embodiment of the invention;
Figure 13 is an enlarged section taken along the line III-III of Fig. 12;
Figure 14 illustrates another example of the tab;
Figure 15 illustrates an easy~to-open synthetic resin bag of the invention in which a layer of bonding agent is provided on the bag body;
Figure 16 illustrates the complete apparatus for manufacturing the easy-to-open synthetic resin bag of the invention;
Flgure 17 is a front elevation of a tear string-positioning member of the apparatus shown in Fig. 16;
Figure 18 is a section taken along the line TV-IV of Fig. 17;
Fiyure 19 is a section taken along the line V-V of Fig. 17; and Figure 20 is a plan view of the essential parts of the apparatus shown in Fig. 16.
As shown in Figs. l and 2, a synthetic resin bag body A is constituted by a laminated film formed by laminating together the required number of layers of synthetic resin film. A base film 1 comprising one or more layers has a heat-sealable plastic film l~ayer 2 laminated on the inner surface thereof. Two laminated films 3 each constituted by laminating together the base film l and the heat-sealable plastic film layer 2 are placed with the heat-sealable plastic film layers 2 facing each other, and the peripheral edges o the laminated films 3 are subjected to ultrasonic or heat sealing to constitute the bag body A. Reference numeral 4 denotes the heat-sealed edges.
A synthetic resin material having such proper-ties as moisture resistance, heat resistance and an ultraviolet-screening property is employed the base rilm 1. For the heat-sealable plastic film layer 2, it is possible to employ any material which enables the welding of the heat-sealable plastic film layers
In a conven-tional bag having a bag body consti--tuted by placing two laminated films formed by laminating together several layers of synthetic resin film over each other and heat-sealing -the peripheral edges thereof, when part of the bag body is opened in order to remove -the con-tents, since the hag body is constitu-ted by laminated films, the bag body is difficul-t to tear and hence the opening pro-cess is difficult.
According to the present invention there is pro-vided an easy-to-open synthetic resin bag comprising: a) a bag body made of a pair of opposed walls, each wall formed from a plurality of layers of synthetic resin film, said walls being sealed together by hea-t around -the periphery thereof to form a seal.ed border region around an unbonded interior of the bag, b) a tear string heat-fused -to -the in-side surface of one of said walls through -the entire length thereof, said tear string having an outer surface thereof concentrically covered with a heat sealable resin, said tear string extending along a line corresponding to a transverse opening to be formed in said bag, said tear string having one end extending into said border region and fused in said bor-der region between said two walls~ c) a pair of straight notches symmetrically disposed at both sides of said -tear string, said notches having outer ends terminating at -the outer-most end of said bag body and inner ends thereof terminating in said border region at a location spaced out-wardly of -the unfused interior of said bag, d) an opening formed in said border region extending transverse to the length of said tear string and be-tween -the inside of said bag and the inner ends of said notches such that said tear string passes through -the width of said opening, said open-ing being adjacent to, but sl.igh-tly spaced from said inner - 1 - ~i~
.~ ;
1L~ 3~
ends of said notches, said opening defining a pulliny tab in said border eg:ion together with said notches, said open-~i~ ing having a length transverse ~to said tear string far ~`1 greater than the distance between inner end sof said notches, said opening having an inner convergent edge closest to the interior of said bag and disposed on said tear string, said s inner convergen-t edge makine an angle '~ of less -than 90 1 with said tear string measured from the opening edge toward ~ the interior of said body.
The present invention thus provides an easy-to-open synthetic resin bag comprising: a bag body cons-ti.-tuted by a laminated film formed by laminating synthetic resin films; a tear string bonded to part of the inner surface of the bag body corresponding to the opening thereof; and a tab formed over an end of the -tear string, whereby pulling the tear s-tring by -the -tab enables the side surface to which the tear string is bonded -to be easily and surely torn, thereby allowing the bag body -to be easily and speedily opened. The invention also provides -to a bag-manufacturing apparatus capable of continuously bonding the -tear string with tabs provided at the ends thereof -to the inner surfaces of the bag bodies in -the bag body manufac-turing process.
The present invention will be further illus-tra-ted by way of the accompanying drawings, in which:-,~ ., Figure l is a front elevation of an easy-to-open synthetic resin bag in accordance wi~h a preferred embodiment of the invention;
Figure 2 is a section -taken along the line I-I
of Fig. l;
Figure 3 is a section taken along the line II-II
of Fig. l;
Figure 4 illustrates a transverse groove foxmed in a tab part of the bag body of the easy~to-open synthetic resin bag of Fig. l;
Figures 5 through 9 illustrate other examples of the transverse groove shown in Fig. 4;
Figure lO is a perspective view of the easy-to-open synthetic resin bag of Fig. l in which the tear string thereof is being pulled;
Figure ll illustra-tes the tab;
Figure 12 is a perspective view of a bag body of an easy-to-open synthetic resin bag in accordance with another preferred embodiment of the invention;
Figure 13 is an enlarged section taken along the line III-III of Fig. 12;
Figure 14 illustrates another example of the tab;
Figure 15 illustrates an easy~to-open synthetic resin bag of the invention in which a layer of bonding agent is provided on the bag body;
Figure 16 illustrates the complete apparatus for manufacturing the easy-to-open synthetic resin bag of the invention;
Flgure 17 is a front elevation of a tear string-positioning member of the apparatus shown in Fig. 16;
Figure 18 is a section taken along the line TV-IV of Fig. 17;
Fiyure 19 is a section taken along the line V-V of Fig. 17; and Figure 20 is a plan view of the essential parts of the apparatus shown in Fig. 16.
As shown in Figs. l and 2, a synthetic resin bag body A is constituted by a laminated film formed by laminating together the required number of layers of synthetic resin film. A base film 1 comprising one or more layers has a heat-sealable plastic film l~ayer 2 laminated on the inner surface thereof. Two laminated films 3 each constituted by laminating together the base film l and the heat-sealable plastic film layer 2 are placed with the heat-sealable plastic film layers 2 facing each other, and the peripheral edges o the laminated films 3 are subjected to ultrasonic or heat sealing to constitute the bag body A. Reference numeral 4 denotes the heat-sealed edges.
A synthetic resin material having such proper-ties as moisture resistance, heat resistance and an ultraviolet-screening property is employed the base rilm 1. For the heat-sealable plastic film layer 2, it is possible to employ any material which enables the welding of the heat-sealable plastic film layers
2 to each other when the peripheral edges of the bag body A are subjected to ultrasonlc or heat sealing.
The position of the opening of synthetic resin bag body A constituted by the laminated film with the arrangement as described above has a tear string B bonded to one inner surface of the bag body A, i.e., one of the heat-sealable plastic film layers 2, as shown in Fig. 2.
It is possible to employ any kind of synthetic resin thread, natural thread ox metal wire thread for the tear string B, and it can be either a single thread or a twisted yarn.
In order to bond the tear string B of this kind to the inner surface of the heat-sealable plastic film layer 2, such methods as follows can be usedo V3~
the outer surface of the tear string B is formed of a heat-sealable resin, thereby enabling the heat-bonding thereof; the tear string B is formed of a twisted yarn consisting of heat-sealable fibers, thereby enabling the heat-bonding thereof; or the surface of the tear string B is coated with a heat-sealable resin b as shown in Fig. 2, thereby enabling the simple bonding of the string to the heat~sealable plastic film layer 2 on heatingO
It must be noted that besides the embodiment wherein the tear string B is bonded to one side wall of the bag body A, the tear string B can be bonded all around the side walls as shown in Figs. 12 and 13. The end C of the tear string B is clamped between the peripheral edges of the laminated films
The position of the opening of synthetic resin bag body A constituted by the laminated film with the arrangement as described above has a tear string B bonded to one inner surface of the bag body A, i.e., one of the heat-sealable plastic film layers 2, as shown in Fig. 2.
It is possible to employ any kind of synthetic resin thread, natural thread ox metal wire thread for the tear string B, and it can be either a single thread or a twisted yarn.
In order to bond the tear string B of this kind to the inner surface of the heat-sealable plastic film layer 2, such methods as follows can be usedo V3~
the outer surface of the tear string B is formed of a heat-sealable resin, thereby enabling the heat-bonding thereof; the tear string B is formed of a twisted yarn consisting of heat-sealable fibers, thereby enabling the heat-bonding thereof; or the surface of the tear string B is coated with a heat-sealable resin b as shown in Fig. 2, thereby enabling the simple bonding of the string to the heat~sealable plastic film layer 2 on heatingO
It must be noted that besides the embodiment wherein the tear string B is bonded to one side wall of the bag body A, the tear string B can be bonded all around the side walls as shown in Figs. 12 and 13. The end C of the tear string B is clamped between the peripheral edges of the laminated films
3 placed over each other. The end C of the tear string B is provided with a tab D, which has the following structure.
Side notches 5, 5' are formed on both sides of the end C in the pulling direction thereof. A transverse groove 6 is formed crossing the tear string B, with a certain space S provided between the transverse groove 6 and the ends of the notches 5, 5', so that the tab D is formed by the side notches 5, 5' and the transverse groove 6.
The space S provided between the ends of the notches 5,5' and the transverse groove 6 is to allow the tab D betweeil the si.de notches S,5' to be supported by -the heat-sealed edge 4 at the peri.pheral edge of the bag body, and the ends of the transverse groove 6 are positioned so as to be at least outside the ends of the corresponding side not-ches 5,5'. Thereby, if the tear lines deviate during in the process of tearing through the spaces S from the ends of -the side notches 5,5', the tear lines will inevitably reach the transverse groove 6.
A variety of shapes are available for the shape of the transverse groove 6 as shown in Fig.s 4 through 9.
It is desirable that. the angle ~ be-tween the transverse groove 6 and the tear string B toward the in-terior a of the bag body should be equal to less than 90.
If the angle is more than 90, the force applied when -tear-ing can be concentra-ted on the area n which is -the inter-section between the tear string B and the transverse groove 6, so that it becomes difficult for the tear string B to tear through the laminated film 3 smoothly.
The bag body A shown in Fig. 12 is formed in such a way that the edges of a flat lam:inated film . fl~
~% IL~ 6 3 are first laid over each other, the doubled edge is subjected to heat sealing in order to form the laminated film 3 into a tubular sha~b, and then the upper and lower ends thereof are sealed to obtain a hermetically sealed bag. Side notches 5, 5' and a transverse groove 6 which are similar to those shown in the first embodiment are formed in the edge of the overlapped seal 7, and khe tab D is formed over the end C of the tear string B.
In such a folded bag, since the end C of the tear string B overlaps the other end C, one of the tear string ends C is cut at a place corresponding to the transverse groove 6 (i.e. at X). Therefore, pulling the tab D enables the pulling of only the tear string B on the other side to teax open the bag body.
The side notches 5, 5' and the transverse groove 6 are formed at both edges of the flat laminated film 3 before forming the overlapped seal 7, and the ends of the laminated film 3 are laid over each~other to from the overlapped seal 7. In this case, each of the side notches 5, r I and the transverse groove 6 is formed, not as a vertical notch-like groove along a line, but as a notch-like groove with a rather larger width, ~ _ thereby absorbing any slightly offset in the positions when the right and left edges are laid over each other, and thus allowing the notches in the right and left edges to align with each other.
It must be noted that when the width of the heat-sealed edge 4 is narrow, the Rart of the heat-sealed edge 4 around the transverse groove 6 is formed so have a wider width as shown in Fig. 14.
Fig. 15 shows a bonding agent 8 applied to the part of the bag body A above the opening thereof, with a peel-off strip 9 removably attached to the bonding agent 8, which are used for closing the opening by bending over the upper part of the bag body A after it has been opened by pulling the tear string B.
An apparatus for manufacturing the above easy-to-open synthetic resin bags shown in Fig. 1 will be described below.
This bag-manufacturing apparatus is const~ucted as shown in Figs. lh through 20. In other words, upper and lower~separating rollers 10, 11 are provided facing each other so as to separate vertically an upper continuous laminated film 3-1 which will be the upper surface of the bag body from a lower continuous laminated film 3-2 which will be the lower surface of 8~
the bag body. On the downstream side of the sepa-~ating rollers 10, 11 as viewed in the direction of flow of the films, rollers 12, 13 ar~e provided which again superimpose the upper and lower laminated films 3-1, 3-2 which were vertically separated from each other, and two pipes 14, 15 can be horizontally displaced in the space between the vertically separated laminated films 3-1, 3-2. Tear string-positioning members 16 are slidably attached to the pipes 14, 15. The tear string-positioning members 16 each have a hole 17 for receiving tear strings B-l pulled from the side. The tear strings B-l passing through the receivlng holes 17 are positioned by the lateral sliding of the tear string-positioning~members 16, thereby allowing tear strings B-l to be sandwiched between the upper and lower laminated films 3-1, 3-2.
The upper and lower laminated films 3-1, 3-2 are su-perimposed, sandwiching between them the tear strings B-l, by means of the rollers 12, 13, are separated vertically again, and then the tear strings B-l and the upper laminated film 3-1 are bonded together by means of a heat-bonding means 18.
On the downstream side of the heat-bonding means 18, a bag making means 19 and a cutting means 20 are provided for heat-sealing and cutting the bag edges, lqJ 3~
thereby manufacturing the bags.
The tear str.ing-positioning members 16 will be described below in greater detail. ~As shown in Figs.
17 through 19, the two pipes 14, 15 are arranged so as to be clamped bv a front plate 21 and a rear plate 22 and fastened by means of a fixing bolt 23. A bolt 24 with an axial hole 25 is screwed into the front plate 21 so as to pass between the pipes 14, 15.
A tear string B-l is i.nserted through the hole 25 of the bolt 24, passed between the pipes 14, 15 and led from a receiving hole 17 formed in the rear plate 22.
A puncher 26, which is provided on the down-stream side of the separating rollers 10, 11~. has the function of applying the transverse grooves 6 to the previously overlapped laminated films 3-1, 3-2 in order to form the tab D.
The side notches 5, 5' constituting the tab D
are formed by the cutting means 20 simultaneously with the cutting of the continuous bag body A.
Since the invention is arranged as described above, in order to remove the contents of the bag body A, pulling the tab D formed in the heat sealed edge 4 around the peripheral edge of the bag body A causes the tear string B to tear through the ~Z~ 3~i laminated film 3 forming the upper surface of the bag body A to open the bag. Accordingly, it is possible to obtain the effect that the bag body A
can be easily and surely opened along the tear string B.
Moreover, when manufacturing continuously bag bodies A of the above type, the continuous laminated films 3-1, 3-2 are vertically separated by means of the separating rollers 10, 11, respectively, and the tear string B is led into the space therebetween from the tear string-positioning member 16 and is sandwiched between the upper and lower laminated films 3-1, 3-2 and then bonded to the upper laminated film 3-1 by means of the heat-bonding means 18, thereby allowing the bag bodies A to be manufactured continuously.
Side notches 5, 5' are formed on both sides of the end C in the pulling direction thereof. A transverse groove 6 is formed crossing the tear string B, with a certain space S provided between the transverse groove 6 and the ends of the notches 5, 5', so that the tab D is formed by the side notches 5, 5' and the transverse groove 6.
The space S provided between the ends of the notches 5,5' and the transverse groove 6 is to allow the tab D betweeil the si.de notches S,5' to be supported by -the heat-sealed edge 4 at the peri.pheral edge of the bag body, and the ends of the transverse groove 6 are positioned so as to be at least outside the ends of the corresponding side not-ches 5,5'. Thereby, if the tear lines deviate during in the process of tearing through the spaces S from the ends of -the side notches 5,5', the tear lines will inevitably reach the transverse groove 6.
A variety of shapes are available for the shape of the transverse groove 6 as shown in Fig.s 4 through 9.
It is desirable that. the angle ~ be-tween the transverse groove 6 and the tear string B toward the in-terior a of the bag body should be equal to less than 90.
If the angle is more than 90, the force applied when -tear-ing can be concentra-ted on the area n which is -the inter-section between the tear string B and the transverse groove 6, so that it becomes difficult for the tear string B to tear through the laminated film 3 smoothly.
The bag body A shown in Fig. 12 is formed in such a way that the edges of a flat lam:inated film . fl~
~% IL~ 6 3 are first laid over each other, the doubled edge is subjected to heat sealing in order to form the laminated film 3 into a tubular sha~b, and then the upper and lower ends thereof are sealed to obtain a hermetically sealed bag. Side notches 5, 5' and a transverse groove 6 which are similar to those shown in the first embodiment are formed in the edge of the overlapped seal 7, and khe tab D is formed over the end C of the tear string B.
In such a folded bag, since the end C of the tear string B overlaps the other end C, one of the tear string ends C is cut at a place corresponding to the transverse groove 6 (i.e. at X). Therefore, pulling the tab D enables the pulling of only the tear string B on the other side to teax open the bag body.
The side notches 5, 5' and the transverse groove 6 are formed at both edges of the flat laminated film 3 before forming the overlapped seal 7, and the ends of the laminated film 3 are laid over each~other to from the overlapped seal 7. In this case, each of the side notches 5, r I and the transverse groove 6 is formed, not as a vertical notch-like groove along a line, but as a notch-like groove with a rather larger width, ~ _ thereby absorbing any slightly offset in the positions when the right and left edges are laid over each other, and thus allowing the notches in the right and left edges to align with each other.
It must be noted that when the width of the heat-sealed edge 4 is narrow, the Rart of the heat-sealed edge 4 around the transverse groove 6 is formed so have a wider width as shown in Fig. 14.
Fig. 15 shows a bonding agent 8 applied to the part of the bag body A above the opening thereof, with a peel-off strip 9 removably attached to the bonding agent 8, which are used for closing the opening by bending over the upper part of the bag body A after it has been opened by pulling the tear string B.
An apparatus for manufacturing the above easy-to-open synthetic resin bags shown in Fig. 1 will be described below.
This bag-manufacturing apparatus is const~ucted as shown in Figs. lh through 20. In other words, upper and lower~separating rollers 10, 11 are provided facing each other so as to separate vertically an upper continuous laminated film 3-1 which will be the upper surface of the bag body from a lower continuous laminated film 3-2 which will be the lower surface of 8~
the bag body. On the downstream side of the sepa-~ating rollers 10, 11 as viewed in the direction of flow of the films, rollers 12, 13 ar~e provided which again superimpose the upper and lower laminated films 3-1, 3-2 which were vertically separated from each other, and two pipes 14, 15 can be horizontally displaced in the space between the vertically separated laminated films 3-1, 3-2. Tear string-positioning members 16 are slidably attached to the pipes 14, 15. The tear string-positioning members 16 each have a hole 17 for receiving tear strings B-l pulled from the side. The tear strings B-l passing through the receivlng holes 17 are positioned by the lateral sliding of the tear string-positioning~members 16, thereby allowing tear strings B-l to be sandwiched between the upper and lower laminated films 3-1, 3-2.
The upper and lower laminated films 3-1, 3-2 are su-perimposed, sandwiching between them the tear strings B-l, by means of the rollers 12, 13, are separated vertically again, and then the tear strings B-l and the upper laminated film 3-1 are bonded together by means of a heat-bonding means 18.
On the downstream side of the heat-bonding means 18, a bag making means 19 and a cutting means 20 are provided for heat-sealing and cutting the bag edges, lqJ 3~
thereby manufacturing the bags.
The tear str.ing-positioning members 16 will be described below in greater detail. ~As shown in Figs.
17 through 19, the two pipes 14, 15 are arranged so as to be clamped bv a front plate 21 and a rear plate 22 and fastened by means of a fixing bolt 23. A bolt 24 with an axial hole 25 is screwed into the front plate 21 so as to pass between the pipes 14, 15.
A tear string B-l is i.nserted through the hole 25 of the bolt 24, passed between the pipes 14, 15 and led from a receiving hole 17 formed in the rear plate 22.
A puncher 26, which is provided on the down-stream side of the separating rollers 10, 11~. has the function of applying the transverse grooves 6 to the previously overlapped laminated films 3-1, 3-2 in order to form the tab D.
The side notches 5, 5' constituting the tab D
are formed by the cutting means 20 simultaneously with the cutting of the continuous bag body A.
Since the invention is arranged as described above, in order to remove the contents of the bag body A, pulling the tab D formed in the heat sealed edge 4 around the peripheral edge of the bag body A causes the tear string B to tear through the ~Z~ 3~i laminated film 3 forming the upper surface of the bag body A to open the bag. Accordingly, it is possible to obtain the effect that the bag body A
can be easily and surely opened along the tear string B.
Moreover, when manufacturing continuously bag bodies A of the above type, the continuous laminated films 3-1, 3-2 are vertically separated by means of the separating rollers 10, 11, respectively, and the tear string B is led into the space therebetween from the tear string-positioning member 16 and is sandwiched between the upper and lower laminated films 3-1, 3-2 and then bonded to the upper laminated film 3-1 by means of the heat-bonding means 18, thereby allowing the bag bodies A to be manufactured continuously.
Claims (3)
PROPERTY OR PRIVILEGE IS CLAIMED ARE DEFINED AS FOLLOWS:
1. An easy-to-open synthetic resin bag comprising:
a) a bag body made of a pair of opposed walls, each wall formed from a plurality of layers of synthetic resin film, said walls being sealed together by heat around the periphery thereof to form a sealed border region around an unbonded interior of the bag, b) a tear string heat-fused to the inside surface of one of said walls through the entire length thereof, said tear string having an outer surface thereof concentrically covered with a heat sealable resin, said tear string extending along a line corresponding to a trans-verse opening to be formed in said bag, said tear string having one end extending into said border region and fused in said border region between said two walls, c) a pair of straight notches symmetrically disposed at both sides of said tear string, said notches having outer ends terminating at the outer-most end of said bay body and inner ends thereof terminating in said border region at a location spaced out-wardly of the unfused interior of said bag, d) an opening formed in said border region extending transverse to the length of said tear string and between the inside of said bag and the inner ends of said notches such that said tear string passes through the width of said opening, said open-ing being adjacent to, but slightly spaced from said inner ends of said notches, said opening defining a pulling tab in said border region together with said notches, said open-ing having a length transverse to said tear string far greater than the distance between inner ends of said notches, said opening having an inner convergent edge closest to the interior of said bag and disposed on said tear string, said inner convergent edge making an angle ? of less that 90°
with said tear string measured from the opening edge toward the interior of said body.
a) a bag body made of a pair of opposed walls, each wall formed from a plurality of layers of synthetic resin film, said walls being sealed together by heat around the periphery thereof to form a sealed border region around an unbonded interior of the bag, b) a tear string heat-fused to the inside surface of one of said walls through the entire length thereof, said tear string having an outer surface thereof concentrically covered with a heat sealable resin, said tear string extending along a line corresponding to a trans-verse opening to be formed in said bag, said tear string having one end extending into said border region and fused in said border region between said two walls, c) a pair of straight notches symmetrically disposed at both sides of said tear string, said notches having outer ends terminating at the outer-most end of said bay body and inner ends thereof terminating in said border region at a location spaced out-wardly of the unfused interior of said bag, d) an opening formed in said border region extending transverse to the length of said tear string and between the inside of said bag and the inner ends of said notches such that said tear string passes through the width of said opening, said open-ing being adjacent to, but slightly spaced from said inner ends of said notches, said opening defining a pulling tab in said border region together with said notches, said open-ing having a length transverse to said tear string far greater than the distance between inner ends of said notches, said opening having an inner convergent edge closest to the interior of said bag and disposed on said tear string, said inner convergent edge making an angle ? of less that 90°
with said tear string measured from the opening edge toward the interior of said body.
2. An easy-to-open synthetic resin bag compri-sed of opposed walls, each of which is formed from several laminated layers of synthetic resin film, said walls being bonded together around the periphery thereof to form a sealed border region around the periphery of an unbonded interior of the bag, a tear string within the unbonded interior of the bag and heat bonded to an inside surface of only one wall while having both ends thereof heatbonded within said sealed border region, said tear string extending along a line corresponding to an opening to be formed in the bag, one end of said tear string extending into said border region and being bonded in said border region between said opposed walls, notches formed in said border region at opposite sides of the end of said tear string, said notches having outer ends extending to an outer edge of the border region and inner ends terminating in the border region at a location spaced outwardly of the unbonded interior of the bag, said bag body having an opening in the bonded border region of the walls which is transverse to the length of the string and between the interior of the bag and the inner ends of said notches, said opening being adjacent to but spaced from the inner ends of said notches, and said string extending between said notches and across said opening, said notches and opening defining a tab with a tear away portion between said inner ends of the notches and said opening in said bonded border region, said opening having a length in a direction transverse to the length of the string at least as great as the distance between the inner ends of the notches, said opening having an inner edge closest to the unbonded interior of the bag which makes an angle ? of equal to less than 90° degrees with the string as measured from the open-ing edge toward the interior of the body, so that the tab tears into the opening and the string is directed by the opening to tear along said one wall of the bag when said tab is grasped and pulled.
3. An easy-to-open bag according to claim 2, further comprising, a bonding agent above said tear string of the bag with a peel-off strip attached to the bonding agent, to enable closing the opening formed by the tear string, by removing the peel-off strip and folding the upper part of the bag over the tear string opening.
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CA000421922A CA1218036A (en) | 1983-02-18 | 1983-02-18 | Easy-to-open synthetic resin bag and apparatus for the manufacture thereof |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CA000421922A CA1218036A (en) | 1983-02-18 | 1983-02-18 | Easy-to-open synthetic resin bag and apparatus for the manufacture thereof |
Publications (1)
| Publication Number | Publication Date |
|---|---|
| CA1218036A true CA1218036A (en) | 1987-02-17 |
Family
ID=4124592
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| CA000421922A Expired CA1218036A (en) | 1983-02-18 | 1983-02-18 | Easy-to-open synthetic resin bag and apparatus for the manufacture thereof |
Country Status (1)
| Country | Link |
|---|---|
| CA (1) | CA1218036A (en) |
-
1983
- 1983-02-18 CA CA000421922A patent/CA1218036A/en not_active Expired
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| Date | Code | Title | Description |
|---|---|---|---|
| MKEX | Expiry |