JPH11348151A - Preparation of bag consisting of resin film - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a method for preparing a bag consisting of a resin film which can keep slip performance between bags each other and can eliminate possibility of breaking loose of a package and can improve printability effect. SOLUTION: A bag is prepd. by a method wherein to a transparent tube-like inflation film 11, its transparent part 12 is made to be left in a belt-like shape in the longer direction and coloring 13 is applied on other parts. Then, double- line heat seal parts 15 and 15 in the width direction crossing the longer direction are formed in the longer direction at a specified pitch on the inflation film 11. In addition, one side end edge of the inflation film 11 is opened by cutting in the longer direction (by a two points dashed line L1) and a space between double-line heat seal parts 15 and 15 is cut (is a two-dot chain line L2) in the width direction of the film 11.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method for producing a bag made of a resin film suitable for packing by packing, for example, fertilizer, curing soil, rice grains and the like.

[0002]

2. Description of the Related Art Conventional polyethylene bags for fertilizer, curing soil, and cereal packaging are called "double bags and semi-double bags", and are continuously printed by a gravure or flexo method using a tubular inflation film. A method has been used in which a heat seal portion serving as the bottom of the bag is formed in the width direction orthogonal to the longitudinal direction of the tube at the bag length (pitch) and cut. That is, as shown in FIG. 5, a polyethylene bag for packaging fertilizer, cured soil, or the like has a bag length (with respect to the inflation film 41 having the same folding diameter as the width of the polyethylene bag to be obtained first). A design 42 such as a character or a pattern having one pitch in the vertical direction) is printed. Next, the heat-seal portion 43 is formed by the heat-seal forming device at every pitch, and the lower side of the seal portion 43 is cut to cut the blown film 41 sequentially into a bag shape. A bag 44 made of a film is manufactured.

It is desirable that the bag 44 made of a resin film manufactured as described above has the following features. When the contents filled in the bag 44 are stored in a warehouse or sold at a store, the bag 4 containing the contents is required.
7 are stacked in several stages as shown in FIG. 7, in which case each bag 44 has a low slip property between the surfaces so that the load does not collapse. (E.g., the coefficient of static friction is 0.3 or more) (b) The display such as the product name, material, and precautions for use of the contents in the bag 44 must be clearly distinguishable.

[0004] The bag 44 is designed to enhance the display effect at the store. D The contents of the bag 44 can be easily confirmed by eyes.

[0005] In order to satisfy the above conditions (b) to (d), the bags 44 are provided with a white underprinting portion 41a on a transparent inflation film 41, and a part of the film 41 is left transparent so that the contents can be seen. The window 41b is formed. After that, desired characters and designs 42 are printed on the white underprinting section 41a. As a result, a bag 44 with a clearly identifiable display and a clear design can be manufactured.

[0006]

However, in the conventional manufacturing method, since the underprinting portion 41a uses a large amount of white ink, it causes a cost increase. Further, in order to satisfy the above-mentioned condition of the slip property, the inflation film 41 having a poor slip property (static friction coefficient: 0.35 to 0.45) is used as a material of the bag 44, but the white underprinting part 4 is used.
By performing the printing process 1a, the slip property of the blown film 41 is good (the coefficient of static friction is 0.15 to 0.15).
0.25), making it impossible to fulfill the original purpose.

There is also a method of printing the design 42 after the white underprinting section 41a, and further applying a coating layer for preventing slippage, but this increases the cost. Further, instead of printing the white underprint 41a,
There is also a method of using a white-colored blown film having poor slip properties from the beginning. However, in this case, although the change in the slip property of the blown film is reduced, since the entire surface is colored, there arises a problem that the contents, which is the above-mentioned requirement 2, cannot be confirmed.

[0008] In addition, in the conventional bag 44, when the contents are wrapped, a phenomenon that the bag 44 is rounded up at the center in a pillow shape as shown in FIG. 7 is observed. Thus, there is a problem that the frictional resistance to the above-mentioned collapse of the load becomes small. In addition, bag 4
4 has a problem that the space for stacking and storing bags is increased in the vertical direction, and the rounded raised bag 44 has a drawback that the display effect of the printed design 42 is reduced by half.

SUMMARY OF THE INVENTION It is an object of the present invention to provide a polyethylene bag with a high printing effect, which solves the above-mentioned problems of the prior art, maintains slip performance between the bags, does not cause collapse of the load, and has a high printing effect. It is in.

[0010]

In order to achieve the above object, according to the first aspect of the present invention, a translucent or transparent portion of a tube body made of a transparent or translucent resin film is placed in a longitudinal direction. A step of coloring the other part while leaving it in a strip shape, and a step of sequentially forming a predetermined width or a two-row heat sealing portion at a predetermined pitch in a width direction crossing the longitudinal direction of the tube main body, The method includes a step of opening one side edge of the tube main body in a longitudinal direction thereof, and a step of cutting a middle portion of the heat seal portion having the predetermined width or a space between two heat seal portions in a width direction of the tube main body.

[0011] According to the second aspect of the invention, in the first aspect, the tube main body is an inflation film.
According to the third aspect of the present invention, in the first or second aspect, the transparent or translucent portion is formed in a linear band shape.

According to the fourth aspect of the invention, the first to third aspects are provided.
In any one of the above, the colored portion of the tube has a step of printing a character or a pattern before the cutting step.

According to the fifth aspect of the present invention, the first to third aspects are provided.
In any one of the transparent or translucent strip,
The bag is formed near the lower edge or the upper edge.

[0014]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS One embodiment of the present invention will be described below with reference to FIGS. First, FIG.
As shown in (1), a tubular inflation film 11 having a folded diameter corresponding to the length of the bag is manufactured. The film 11 is formed by extruding a molten polyethylene into a tube by an inflation molding method.

In the manufacturing process of the above-mentioned blown film 11, the transparent portion 12 is used as the transparent portion 12 so that the area where the contents can be confirmed, that is, 10 to 20% of the film 11 on the side to be the surface of the bag, is used. A colored portion 13 such as bad white is formed at the same time. For example, in the case of a white colored portion 13, titanium fight is mixed as a pigment into molten polyethylene. The strip-shaped transparent portions 12 can be easily formed in the longitudinal direction of the inflation film 11, but it is difficult to form the transparent portions 12 in the width direction sequentially at a predetermined pitch in the longitudinal direction. This is not possible with molding methods.

The coefficient of static friction of the outer surface of the polyethylene forming the blown film 11 is 0.35 to 0.35.
It is set to 0.45 g. By forming the colored portion 13, the static friction coefficient of this portion is 0.30 to 0.3.
Although it changes with time to 40 g, the coefficient of static friction when white printing is performed after film formation as in the past, 0.15 to 0.1.
It can be kept larger than 25 g. The static friction coefficient is a coefficient representing a friction force when a stationary object starts to move.

In order to set the static friction coefficient of the surface of the film 11 to 0.35 to 0.45 g, a polyethylene resin grade to which a small amount of a slip material is added is used.
For example, calcium carbonate is used as an inorganic filler (compounding agent) in polyethylene, for example, 5 to 30% by weight in the film 11.
Added. It is not clear why the addition of calcium carbonate increases the coefficient of static friction, but it is thought to be based on the surface properties of the particles of calcium carbonate itself, the function of calcium carbonate to prevent the transfer of lubricant, and the hygroscopic properties of calcium carbonate. . When this calcium carbonate is added, the state where the coefficient of static friction is increased can be maintained even when printing the following characters and patterns.

As shown in FIG. 2, a pattern 14 such as a product name or a design is continuously printed on the blown film 11 by using the size corresponding to the width of the bag as a pitch by a gravure or flexo method on a colored portion.

Next, the inflation film 11
On the other hand, two heat seal portions 15, 15 are formed in the width direction at a predetermined pitch in the longitudinal direction. Further, one side edge of the blown film 11 is indicated by a two-dot chain line
The opening 16 is formed as shown in FIG.

The bag shown in FIG. 3 can be manufactured by cutting the space between the two heat seal portions 15 and 15 in the width direction of the film 11 as shown by a two-dot chain line L2 in FIG. The bag manufactured by this method has the following features.

(1) Since two white underprinting plates as in the prior art are not required, the printing cost can be reduced. (2) Since there is no white underprint, there is no change in the slip property of the film due to ink, and low slip properties can be maintained.

(3) Since the bag is intercepted with respect to the film flow, the pitch is shortened and the printing cost is reduced. (4) As shown in FIG. 3, the shape of the bag is such that the sealing portion is on both sides, so that the stitches (knobs) are attached, and when the contents are packed, the bag is stable as shown in FIG. It is difficult to form a pillow like a conventional bag. Therefore, when a plurality of bags are filled with the contents and stacked, the collapse of the load can be prevented. In addition, since the contact area increases, the laminated state can be stably maintained.

The above embodiment can be modified as follows. -Instead of the two heat seal portions 15, 15, a single heat seal portion 15 may be formed to have a predetermined width, and a central portion of the heat seal portion 15 may be cut.

FIG. 2 shows a process of forming the opening 16;
Although the film 11 is cut as shown by the two-dot chain line L1, this step may be performed after the step of cutting the heat seal portions 15, 15.

[0025]

Since the present invention is configured as described above, it has the following effects. According to the first aspect of the present invention, it is possible to maintain the slip performance between the bags, eliminate the risk of collapse of the load, and improve the printing effect.

According to the second aspect of the present invention, since the tube main body is formed of an inflation film, it is possible to simultaneously form a film having a transparent or translucent portion and a colored portion, thereby reducing costs. be able to.

According to the third aspect of the present invention, since the transparent or translucent portion is formed in a linear band shape, the contents can be easily checked over the entire width of the bag.

[Brief description of the drawings]

FIG. 1 is a perspective view of an inflation film showing an embodiment embodying a bag manufacturing method of the present invention.

FIG. 2 is a perspective view in which a pattern and a heat seal portion are applied to an inflation film.

FIG. 3 is a perspective view showing one bag.

FIG. 4 is a sectional view showing a state in which contents are filled in a bag and stacked.

FIG. 5 is a perspective view showing a conventional bag manufacturing method.

FIG. 6 is a perspective view showing one conventional bag.

FIG. 7 is a cross-sectional view showing a state where a conventional bag is filled with contents and laminated.

[Explanation of symbols]

11: blown film, 12: transparent part, 13
... Colored part, 15 ... Heat seal part.

Claims (5)

[Claims] 1. A step of coloring a tube main body made of a transparent or translucent resin film in another portion while leaving a translucent or transparent portion in a strip shape in a longitudinal direction; A step of sequentially forming a predetermined width or two heat-sealed portions at a predetermined pitch in a width direction intersecting the longitudinal direction; a step of opening one side edge of the tube body in the longitudinal direction; Cutting the intermediate portion of the heat seal portion or the space between the two heat seal portions in the width direction of the tube main body. 2. The method according to claim 1, wherein the tube body is made of a resin film which is an inflation film. 3. The method for manufacturing a bag according to claim 1, wherein the transparent or translucent portion is formed of a resin film formed in a linear band shape. 4. The method according to claim 1, wherein
A method for manufacturing a bag made of a resin film, comprising a step of printing characters or patterns on the colored portion of the tube before the cutting step. 5. The method according to claim 1, wherein
A method for manufacturing a bag, wherein the transparent or translucent belt portion is formed of a resin film formed near a lower edge or an upper edge of the bag.