JPS6030273B2 - How to make paper bags - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a method for manufacturing a paper bag, in which a main body of the bag with a flap is formed by continuously forming a bag main body with a flap from two or more layers of long belt-shaped bag material with the innermost layer being a synthetic resin layer.

In general, multilayer paper bags are made by cutting perforations at predetermined positions in a multilayered long strip of bag material, forming the paper into a tube in the longitudinal direction, and then cutting the bag on both sides of the perforations. It was manufactured by supporting and tensioning the bag, then punching the perforations to cut it, continuously forming a single bag main body, and then pasting the bottom or the opening.

A paper bag with a flap is manufactured in substantially the same manner, but in this case, the perforations are step-shaped, and the perforations form a part that becomes a flap when unfolded. By the way, in recent years, many paper bags with two or more layers, the innermost layer of which is a synthetic resin layer, have been on the market because they have excellent features such as high strength and moisture and waterproof properties.

As described above, the method of forming the bag main body in such a multilayer paper bag, especially a multilayer paper bag with a flap, is to make perforations in a step-like manner at the time of unfolding before forming the tube.
One possible method is to cut the perforated portion by forcefully punching the tube after forming the tube. However, as mentioned above, when the innermost layer is a synthetic resin layer, even if it is a thick layer completely separated from the second layer paper bag, the second layer
In the above-mentioned general method of punching the paper layer and the synthetic resin layer of the paper layer and the outer layers at the perforation, it was not possible to cut each layer uniformly and flush at the perforation.

This is because perforations cannot be made on the inner and outer layers at the same time,
This may be due to misalignment of the perforations between the inner and outer layers, or a difference in the elongation rate between the paper layer and the synthetic resin layer, but in any case, with the conventional method, it is not possible to obtain a cut surface that is consistent in quality and at the base. There was a drawback that a bag with a flap could not be obtained.
In addition, for example, in the case of a two-layer bag in which the inner layer (la) is made of polyethylene film and the outer layer (lb) is made of kraft paper, it is not possible to make perforations with the polyethylene film alone because it stretches, so the polyethylene film and kraft paper are combined. Then, you will make perforations. For this reason, even if you want to make a flap using only kraft paper, the polyethylene film overlaps the flap part, and the opening (bottom) cannot be bonded using regular adhesive. It was not possible to manufacture anything that was This invention was made in order to eliminate the above-mentioned drawbacks, and it forms a main body of a bag with a flap, which has a uniform cut surface of uniform quality, and which allows the flap-corresponding parts of the inner and outer layers to be formed into any shape. The purpose of the present invention is to provide a method for manufacturing paper bags that can be manufactured using the following methods.

Embodiments of the present invention will be described below with reference to FIGS. 1 to 9. FIG. 1 is a partially cutaway perspective view of an example of a tube used in the method for manufacturing paper bags according to the present invention. As can be seen from this figure, the method for manufacturing paper bags according to the present invention is A long belt-shaped bag material with a synthetic resin layer la as the inner layer and two or more layers of paper scraps lb as the outer layer is formed into a tube shape in the longitudinal direction, and then cut as appropriate to form a continuous single tube. 1 is used. In this case, as shown in FIG. 1, the tube 1 has a portion 2a left as a flap 2 of a predetermined length 1 from the edge green on at least the outermost layer, here, on both sides of the paper layer lb, with a corresponding residual portion. A notch 3 is provided in each case to separate it from the portion 2b. In the case illustrated in FIG. 1, the notch 3 is provided so that its entire length is along the side edge of the tube 1, but it may be provided without having its entire length along the side edge of the tube 1 at all (see FIG. (see FIG. 6), and a part of its length may be provided along the lead on the tube 1 side (see FIG. 6).
Further, the cut 3 is usually provided when the bag material is expanded before the tube 1 is formed, and it is easier to do so, but it may be provided after the tube is formed into a tube. Next, the remaining portion 2b of the tube 1 is cut off all at once as shown in FIGS. 2a to 2c, for example.

Here, the black circles in FIG. 2 a to c are the adhesive (interlayer glue) that adheres the synthetic resin layer la and paper layer lb near the oribe of the tube 1, and the end portions of both layers la and lb are integrated. This is useful for cutting off the remaining portion 2b all at once. That is, the tube 1 provided with the cut 3 (see FIG. 2a) is first fed into the opening device, here the suction SU. Tube 1 sent to suction SU is
The part 2a to be left as the flap 2 and the remaining part 2b are sucked from opposite sides and the part 2a to be left as the flap 2.
Then, the remaining portion 2b is expanded (see FIG. 2b), and these portions 2a and 2b are sent to the cutter CU in a separated state. The cutter CU cuts off the remaining portion 2b from the tube 1 all at once from the end edge at a length 1' shorter than the predetermined length 1 as shown in FIG. 3 (see FIG. 2c); A bag main body 4 with a flap 2 as shown in FIG. 3 is formed. Thereafter, the bottom or top is pasted in a conventional manner to obtain a paper bag (see Figure 4). In the above-mentioned embodiment, the opening device for expanding the space between the portion 2a to be left as the flap 2 and the remaining portion 2b is replaced by the suction S.
Although the case where the configuration is made up of U has been described, the configuration is not limited to this only.

For example, the portion 2a to be left as the flap 2 is not made into a rectangle as in the above-mentioned embodiment (see FIG. 1), but is cut into a trapezoid or hexagon as shown in FIG. 5 or 6. The flap 2 may be configured with a pressing device that presses the corner portion of the remaining portion 2b corresponding to the portion left as the flap 2 (the portion shown in a checkered pattern in FIGS. 5 and 6) from the side of the portion 2a. FIGS. 7a to 7c are diagrams for explaining the formation of the main body of the bag with a flap when the opening device is constituted by a pressing device in this way.

That is, here, first, the tube 1 in which the notch 3 is provided and the portion 2a to be left as the flap 2 is rounded is fed into the pressing device PU which is the opening device (
(See Figure 7a). Next, the tube 1 fed into the pressing device PU is pressed from the side of the portion 2a where the corner portion of the remaining portion 2b is left as a flap 2, so as to bridge between the portion 2a and the remaining portion 2b, which are left as a flap 2. Figure 7b
), and thereafter the cutter CU' is used in almost the same way as in the above embodiment
Therefore, the remaining portion 2b is cut off from the tube 1 (see FIG. 7c) to form the main body of the bag with a flap. Further, in the above embodiment, the inner layer is a synthetic resin layer l.
a. A two-layer paper bag whose outer layer is a paper layer lb, and also has a “machi”
Although the explanation has been given using a paper bag without a gusset as an example, it goes without saying that the present invention can also be applied to a paper bag with three or more layers or a paper bag with a gusset.

The paper bags produced by the method of this invention are particularly useful for packaging frozen products formed into block shapes, packaging for medicines, and other chemical products because of their strength, especially their resistance to tearing when dropped, and their moisture-proof or waterproof properties. suitable for

FIGS. 8a and 8b are a plan view and a sectional view showing an example of a paper bag for packaging block-shaped frozen products to which the method of the present invention is applied.

Here, the outer layer lb is made of 150 to 200 yen kraft paper, and the inner layer la is a polyethylene film.The polyethylene film is folded at the overlapped part of the inner layer la and the outer layer lb, and the contents are sealed as a seal. It is designed to prevent leakage, and the opening can be easily attached using one-touch glue 5. FIG. 9 is a cross-sectional view showing the essential parts of an example of a paper bag for packaging chemical products to which the method of the present invention is applied. , which shows an example of adopting the so-called W pinch back, and this kind of bottom sticking (mouth sticking) is particularly effective for reliably sealing toxic chemicals.

As explained above, according to the present invention, a paper bag made of two or more stacked layers with the innermost layer as the synthetic resin layer la can be cut mainly to form the flap 2 by punching the perforation part after making the conventional perforations. Instead of searching for a method of cutting, we decided to cut straight lines using a cutter CU, etc., making it possible to cut the inner and outer layers, including the synthetic resin layer la, evenly, resulting in beautiful striped cuts of uniform quality. It is possible to form a bag main body 4 with a flap having a surface, and the inner and outer layers la, l
This has the advantage that the portion b corresponding to the flap 2 can be formed into an arbitrary shape.

[Brief explanation of the drawing]

FIG. 1 is a partially cutaway perspective view showing a main part of an example of a tube used in the paper bag manufacturing method according to the present invention, and FIG.
Figures a to c are diagrams for explaining an example of forming a main body of a bag with a flap when the opening device used in the method of this invention is configured with a suction, and Figure 3 is a diagram formed according to Figures 2 a to c. FIG. 4 is a perspective view showing a main part of an example of a main body of a bag with a flap, and FIG. , FIG. 5 and FIG. 6 are respectively plan views showing the main parts of other examples of the tube used in the method of the present invention, and FIG. 7a.
Figures 8a to 8c are diagrams for explaining an example of forming a main body of a bag with a flap when the opening device used in the method of the present invention is configured with a pressing device, and Figures 8a and 8b are diagrams showing a block-shaped bag to which the method is applied. FIG. 9 is a plan view and a sectional view showing an example of a paper bag for packaging frozen products, and FIG. 9 is a sectional view showing a main part of an example of a paper bag for packaging chemical products. 1...tube, la...synthetic resin layer (innermost layer), lb...paper layer (outer layer), 2...
・Flap, 2a...Part to be left as flap, 2b...Remaining part, 3...Notch, 4
... Mainly bags with flaps, SU...,. ．． suction,
C.U.・・・． ...Cutter, PU...Press device. Figure 1 Figure N Boat diagram Figure 3 Figure 4 Figure 5 Figure 6 Figure 8 Figure 9

Claims (1)

[Claims] 1 A long belt-shaped bag material made of two or more stacked layers, with the innermost layer being a synthetic resin layer and the outer layer being a paper layer, is formed into a tube shape in the longitudinal direction, and then cut as appropriate to continuously form a single bag main body. However, in this method of manufacturing a paper bag in which the main body of the bag is pasted on the bottom or the top, there is a step, at least on both sides of the outermost layer, for separating the portion that is left as a paper flap of a predetermined length from the edge from the corresponding remaining portion. After forming a tube with each cut, the portion to be left as the flap and the remaining portion are widened using an opening device, and the remaining portion is cut from the edge to a length shorter than the predetermined length from the tube by straight cutting. A method for producing a paper bag, which comprises cutting off all at once to form a main body of the bag with a flap.