JPH0641305B2 - Stand type synthetic resin bag with bottom gusset - Google Patents

Description

The present invention relates to a stand-type synthetic resin bag body with a bottom gusset.

[Conventional technology]

As shown in FIG. 9, a conventional bag made of synthetic resin with a bottom gusset has two folded film bottom members 103 sandwiched between two films 101 and 102 which are bag members, and the two faces The left and right end portions of the films 101 and 102 and the left and right end portions of the sandwiched bottom member 103 are adhered to each other, and as shown in FIG. 9, the lower end edges of the bottom member 103 facing the lower end edges of the two surfaces of the film material are attached to each other. It was formed by individually adhering c.

As described above, in the conventional bottomed bag body, the main body member and the bottom member are manufactured separately, and the two are combined and bonded, so that the bottom surface is not peeled off due to various pressures. Has been done.

For example, when the conventional bag is filled with contents such as powder or liquid having high fluidity, the vibration of the pressure shock received by the contents due to heavy pressure or rocking during loading or transportation. Has the strongest effect on the bottom surface, so that inconveniences such as peeling of adhesion on the bottom surface occur.

Here, in order to prevent the peeling of the adhesive on the bottom surface as described above, the side adhesion of the bottom surface is made into a slope shape to increase the adhesive area. Has not yet been eliminated.

In addition to the current situation, recently, bagging by automatic filling machines has been increasing, so that further measures for strengthening adhesion are needed.

That is, when the contents are bag-filled by the automatic filling machine, compressed air is injected from the bag mouth to open the bag in order to smoothly fill the contents. However, since this injection pressure directly hits the bottom surface portion, if the adhesion was weak or there was uneven adhesion, the adhesion was easily peeled from the area and the bottom was missing. It should be noted that when the bag member is thick, incomplete adhesion is particularly likely to occur, so that the occurrence rate of the bottom missing is high.

However, despite the fact that the adhesion of the bottom surface has been strengthened as described above, the cause of the bottom omission has not been eliminated yet, the bag member and the bottom member are manufactured separately, and both are assembled. The point is that they must be bonded together. That is, the root cause of the peeling is that the above-mentioned two are bonded,
In order to eliminate this cause, it can be said that the development of a bag having a structural form that does not require adhesion on the bottom surface is a fundamental problem to be solved.

In addition to the above, there is a problem in workability in filling the bag with the contents.

That is, as a common feature of the bag with bottom gusset, the work of expanding the bottom part is always performed in either machine or manual work so that smooth filling can be performed before filling the contents, but for the following reasons. There was a difficulty in workability.

That is, generally speaking, a stand-type bag with a bottom gusset is made of a thick film that does not bend in order to maintain the three-dimensionality.

Therefore, in order to make the adhesion of the bottom member, which also serves as the stepladder and the bottom surface, uniform with the bag body, the same thick film as the bag body is used for the adhesion.

As described above, in the conventional bottomed bag, since the bottom member is formed in a thick shape, the bottom part is hard to fold and therefore does not spread smoothly. However, the expansion of the work had a significant decrease in work efficiency.

In addition to the above-mentioned known example, there is also a bag body in which the bottom portion of the film forming the bag body is folded and only the both side portions of the bag are bonded. However, in the case of the bag body, even if it is not necessary to adhere the bottom portion, when the article is stored, the bottom portion hangs down, so there is no stand property.

[Means for solving problems]

In order to solve the above problems, the present invention provides a bag having a synthetic resin bottom gusset portion and a step portion, which includes side wall portions 3 and 3, step portions 5 and 5, and a bottom portion 4. Rib-shaped ridges F, F are formed on both ends over the entire width of the bag, and the bottom surface portion projects into the side wall portions 3, 3, and further, with the rib-shaped ridges F, F of the bottom surface portion 4 as the starting points, The side wall portions 3 and 3 are formed on the upper side and the step portions 5 and 5 are formed on the lower side, and the side wall portions 3 and 3, the step portions 5 and 5, and the bottom surface portion 4 are integrally formed by extrusion.

Further, if necessary, as in the second invention, the bottom surface portion 4
Is thinner than the side wall parts 3 and 3 and the stepladder parts 5 and 5.

According to the present invention, since the bottom surface portion 4 is completely integrated with the side wall portions 3 and 3 and the stepladder portions 5 and 5 as described above, the bottom surface portion does not peel off during the bag packing operation, and the bottom strength is sufficient. At the same time, it has the advantage of being easy to fold.

[Explanation of Examples]

(Manufacturing Method of Bag) The bag of the present invention as shown in FIGS. 1 and 2 is manufactured as follows.

As shown in FIG. 1, the die 1 is provided with a large cylindrical slit 2a and a small cylindrical slit 2b in communication with each other.
The film discharged and formed from the large and small cylindrical slits 2a and 2b has a large cylindrical portion a, a small cylindrical portion b, and a bottom member c. Then, the bottom member c projects into the large cylindrical portion a by adjusting the internal pressure of the film cylindrical portion. (State of FIG. 2) At this time, rib-shaped ridges F, F are provided at both ends of the bottom member c on the small cylindrical portion b side.
Are formed over the entire length of the discharged film.

It is considered that the cause of the rib-shaped ridges F, F is that the surplus amount of the resin swells after being discharged from the die 1 in the resin merging portions of the large and small cylindrical portions a, b.

However, when the small cylindrical slit 2b is projected to the large cylindrical slit 2a as shown in FIG. 2, rib-shaped ridges F, F are generated at both ends of the bottom member c on the large cylindrical portion a side.

In the formation of the large and small cylindrical film, the film portion between the rib-shaped ridges F, F of the bottom member c projects into the large cylindrical portion a, and does not come into contact with the outside air. In addition, since direct cooling cannot be performed, cooling is slower than other portions, and therefore is in a soft state. Therefore, only this portion is affected by the internal pressure, that is, other portion, that is, the large cylindrical portion a,
The film is thinner than the film of the small cylindrical portion b.
That is, the outer film portion is cooled and hardened, but only the bottom member c is delayed in hardening. Therefore, if the internal pressure of the small cylindrical portion b is made slightly higher than that of the large cylindrical portion a, the bottom member c
The others are thinner than the other parts.

As described above, this deformed tubular film material has a large cylindrical portion a,
The small cylindrical portion b and the bottom member c are rib-shaped ridges F, F of the bottom member c.
Is formed as an integral extruded product.

Next, the film material is taken up by a winding frame to carry out bag making, and is transferred to a bag making process.

In winding the tubular film material, the bottom member c starting from the rib-shaped projections F and F is folded into the circumference of the large cylindrical portion a starting from the same rib-shaped projections F and F. On the other hand, on the other hand, the small cylindrical portion b is wound up on the winding frame in such a manner that the rib-shaped ridges F, F are projected to the outside of the circumference. That is, from the state of FIG. 1, as shown in FIG. 1, the large and small cylindrical portions a and b have a flat shape in which the bottom member c projects into the large cylindrical portion a as a rib-shaped ridge. This state is enlarged and shown in FIG.

Finally, both outer ends of the large and small cylindrical portions a and b are cut, and the side wall portions 3 and 3 and the step portion 5 are cut as shown in FIG.
5, the bottom portion 4 is formed, and as shown in FIG.
Both ends of the bag are cut according to the size of the bag to form the welded portions 7 on both sides, and the product d is obtained.

Instead of the manufacturing method shown in FIG. 1, the slit of the die 1 may be formed into a shape in which the small cylindrical slit 2b projects from the corresponding portion into the large cylindrical slit 2a as shown in FIG.

By doing so, the work of projecting the film portion between the rib-shaped ridges F, F into the large cylindrical portion a by adjusting the internal pressure as in the embodiment of FIG. 1 is reduced. However, in the case of forming the slit type shown in FIG. 2, it is difficult to increase the cost.

As described above, in any of the embodiments with the die slits shown in FIGS. 1 and 2, the bottom member c still projects into the large cylindrical portion a, and the projecting shape is almost the same. In manufacturing the material for the bag body, it does not matter which slit type shown in FIGS. 1 and 2 is selected and formed.

When any of the die slits shown in FIGS. 1 and 2 is used, rib-shaped ridges are formed at both ends of the bottom member c. Then, with the rib-shaped ridges F, F as the starting points, as described above, the film portions which become the side wall portions 3, 3, the bottom surface portion 4, and the step portions 5, 5 are formed separately. However, as described above, the positions where the rib-shaped ridges F, F are generated differ in the case of FIGS.

As described above, the rib-shaped ridge has the bottom member c, the large and small cylindrical portions a,
It occurs in the part where b is connected, and bottom member c
A frame-shaped ridge is formed over the entire width of the bag along both ends of.

(Structure of the bag body) The synthetic resin bag body d formed from the above-mentioned deformed tubular film material is provided with rib-shaped ridges over the entire length of the boundary between the bottom surface portion 4, the side wall portion 3 and the stepladder portion 5. An annular projection is formed over the entire width inside the bag.

The rib-shaped convex portions F, F are used as the starting points to form the bag side wall portions 3 and 3, the bottom portion 4 and the step portions 5 and 5 as an integral extruded product, each of which is a bottom portion 4.
The rib-shaped ridges F and F are used for the division.

The bottom surface portion 4 is formed as a film thinner than the film forming the side wall portions 3 and 3 and the step portions 5 and 5.

FIG. 5 shows a state in which the filling object 6 is filled. At this time, the rib-shaped ridges F at both ends of the bottom surface portion 4 are formed in a frame shape over the entire width of the bag.

Therefore, as shown in FIG. 7 and FIG.
The bottom portion 4 is less likely to be expanded when filled with, and as a result, the degree to which the bottom portion 4 hangs is reduced.

[Effects of First Invention] The effects of the first invention are as follows.

The bottom surface portion of the bag body according to the present invention does not have a structure in which the bag body member and the folded bottom member are adhered to each other unlike the conventional product, but the side wall portions 3, 3, the stepladder portions 5, 5, and the bottom portion 4 are integrated. Since it is an extruded product, the bottom part has no adhesive part.

Therefore, even if various pressures during the bag packing operation or injection pressure by compressed air are applied to the bottom surface portion, the bottom surface portion does not come off.

Since the bag body of the present invention does not have a structure in which the bag member and the bottom member are bonded to each other as in the conventional case, in order to strengthen the bonding between them,
There is no need to purchase a means for expanding the adhesion area by making the adhesion of the bottom end portion into a sloped adhesion, or to use a means for strengthening the adhesion, which is costly by making a hole in the bottom surface member.

Since rib-shaped ridges F, F are formed over the entire width of the bag at the boundary between the bottom surface portion 4 and the step portion 5, or the side wall portion 3, the bottom surface portion 4 is so-called frame-tightened, so that the packaged object 6 Even if it receives a pushing force to spread, the bottom surface portion 4 does not droop too much and does not deform.

Further, when the bottom surface portion 4 hangs, the amount of sagging decreases, and the uprightness of the bag is not unstable.

(Effect of Second Invention) The second invention, that is, the effect of thinning the bottom surface portion 4 will be described below.

Since the bottom surface portion 4 is thin, it has a small elastic force and tends to be flat when folded. Therefore, a large number of sheets can be packed in a cardboard box or the like, so that the transportation cost can be reduced.

Since the bottom portion 4 is thin and flexible, it is not necessary to force the boxing work to perform the packing work, and the work efficiency is high.

On the other hand, at the user stage, when filling the contents, it is necessary to expand the flat bottom surface, which is the opposite of the above. In this case, the thinner the bottom portion is, the softer it is, so that the bottom portion can be easily widened.

[Brief description of drawings]

FIG. 1 shows a method for producing the material of the present invention. FIG. 2: Another embodiment of the die is shown. FIG. 3: Broken-out cross-sectional view of the material of the present invention FIG. 4: Broken-out cross-sectional view of product d using the material of the present invention FIG. 5: Broken-out cross-sectional view of the same when the object to be packed 6 is filled FIG. 6 : Cross-sectional view of the material of the present invention Fig. 7: Front view of the product d when the object to be packaged 6 is not filled Fig. 8: Front sectional view of the product d when the object to be packaged 6 is also filled Fig. 9: Conventional bottom gazette Fig. 9: Perspective view before the bottom gusset is adhered in the method for manufacturing the bag, Fig. 9: Sectional view after the bottom gusset is also adhered 1: Die 2a: Large cylindrical slit 2b: Small cylindrical slit 3: Side wall part 4: Bottom part 5 : stepladder portion 6: the packaged articles 7: both side welded portion a: the large cylindrical portion b: small cylindrical portion c: the bottom member x-x: center line O _a: center O _b of the large cylindrical portion a: the small cylinder portion b Center d: Product F, F: Connection part between large and small cylindrical parts a and b 101, 102: Plastic film 103: Bottom Wood

Claims (2)

[Claims] 1. A bag body having a synthetic resin bottom gusset portion and a step portion, the bag body including side wall portions 3 and 3, step portions 5 and 5 and a bottom portion 4 below the side wall portions, and a bottom portion 4. Rib-shaped ridges F, F are formed on both ends of the bag over the entire width of the bag, and the bottom surface portion projects from the rib-shaped ridges into the side wall portions 3, 3, and further, the ribs of the bottom surface portion 4 are formed. Starting from the convex ridges F, F, the side wall portions 3 and 3 are located above and the step portions 5 and 5 are located below.
And the side wall portions 3, 3, the step portions 5, 5, and the bottom portion 4 are integrally formed by extrusion, and are made of a synthetic resin of a stand type with a bottom gusset. Bag. 2. A bag body having a synthetic resin bottom gusset portion and a step portion. The bag body is composed of side wall portions 3, 3, lower step portions 5, 5 and a bottom portion 4, and a bottom portion 4. Rib-shaped ridges F, F are formed on both ends of the bag over the entire width of the bag, and the bottom surface portion projects from the rib-shaped ridges into the side wall portions 3 and 3, and the rib shape of the bottom surface portion 4 is formed. Starting from the ridges F, F, the side wall portions 3, 3 are located above the ridges F, and the step portions 5, 5 are located below.
And the side wall portions 3, 3, the step portions 5, 5, and the bottom surface portion 4 are integrally formed by extrusion, and the film thickness of the bottom surface portion 4 is the side wall portions 3, 3. 3. A stand-type synthetic resin bag body with a bottom gusset, characterized in that it is formed thinner than the film thickness of the stepladder parts 5, 5.