JPH0542118U - Flat bottle made of plastic with excellent squeeze properties - Google Patents

Abstract

(57) [Summary] [Purpose] To provide a flat bottle made of plastic having a bottomed, self-supporting bottle and having no squeeze property, which does not have an air bag after the contents are discharged. [Structure] The entire bottle is made of a low-rigidity resin, and only the front wall and / or the back wall is made by an in-mold label method using a resin having a higher rigidity than that, or
Alternatively, a large-area front wall and / or back wall is formed by an in-mold label method using high-density polyethylene, and side walls are formed of a low-rigidity resin such as low-density polyethylene. [Effect] With the above configuration, the table
Since the back surface has an appropriate rigidity and the side wall is configured to be easily deformed, the bottle as a whole is an excellent flat bottle made of squeeze while maintaining self-supporting property.

Description

[Detailed description of the device]

[0001]

[Industrial applications]

 The present invention relates to a plastic flat bottle having excellent squeeze property, and more specifically, a plastic flat bottle having a bottom with excellent squeeze property in which front and back surfaces and side surfaces are made of resins having different rigidity. Regarding

[0002]

[Prior Art]

 Bottomed bottles made of thermoplastic synthetic resin are widely used in various fields and are used as transparent, translucent or colored bottles depending on the type of contents to be stored. Since a bottomed bottle needs to have a self-supporting property when placed on the floor or the like, it is usually molded from a resin having high rigidity. Also, when molding a plastic hollow container, multiple synthetic resins are co-extruded to form a colored vertical pattern on a part of the container wall, and a partial pattern is formed on the wall surface of the container. It has been known for a long time as disclosed in Japanese Patent No. 3728084, and a state in which a colored resin is embedded in a sandwich shape by co-extrusion inside a transparent or translucent synthetic resin layer forming the wall surface of a plastic container. A container constituted by is also disclosed in Japanese Utility Model Publication No. 44-11114.

Even if these plastic containers are made by printing after molding to increase the added value of the container, in containers made of a polyolefin-based synthetic resin that has a poor affinity for printing ink, the annular slit of the molding die is used. By providing a technique for extruding colored resin, multiple resins can be extruded simultaneously, and molding and coloring can be achieved at the same time, resulting in a plastic container with an increased added value, providing a partially colored container. It is evaluated in terms of what it did.

[0004]

[Issues to be solved by the device]

 By the way, as mentioned above, plastic bottles usually have both the rigidity to restore the original shape and the flexibility to maintain self-supporting property even when they are deformed by applying external pressure. After discharging the object, the volume of the discharged content remains as a space in the container. However, depending on the type of contents to be filled in the plastic bottle, there are some such as miso and ketchup, which are easily oxidized and deteriorated by contact with air. It is not preferable that there is a space inside the bottle after partial discharge. Therefore, there is a need for a bottle with excellent squeeze properties that does not cause an air bag phenomenon after the contents are discharged.

Conventionally, in the tube container, it is found that so-called squeeze property is considered in which the restoring force after discharging such contents is suppressed. However, in a tube container, one end of plastic extruded in a tubular shape is heat-sealed, and the other end is joined by heat-sealing, and the size of the container is limited due to manufacturing cost or manufacturing restrictions. However, a large-capacity plastic container with excellent squeeze properties is not yet known.

[0006]

[The purpose of the device]

 Therefore, an object of the present invention is to provide a flat bottle having a good squeeze property even though it is a bottomed plastic bottle.

[0007]

[Means for Solving the Problems]

 The present invention has been proposed in order to achieve the above-mentioned object, and the front and back surfaces of the flat bottle, that is, the large-area walls are made of a material having relatively good shape retention, and the flat bottle has a side surface. In other words, the feature is that the small area wall is made of a highly flexible material. That is, according to the present invention, the entire bottle is a bottomed flat bottle made of a low-rigidity thermoplastic resin, and the large-area front wall and / or back wall of the bottle is made of a bottle-forming resin. Also provided is a plastic flat bottle having excellent squeeze characteristics, which is characterized by being formed by an in-mold label method using a highly rigid thermoplastic resin. Furthermore, according to the present invention, in a flat bottomed bottom obtained by co-extruding a plurality of synthetic resins, a large-area front surface wall and / or back surface wall is formed by a high-density polyethylene in-mold label method, A small-area side wall is composed of low-density polyethylene, ethylene-vinyl acetate copolymer, or linear ethylene-α-olefin copolymer (in this specification, it may be simply referred to as linear low-density polyethylene). The flat bottle made of plastic with excellent squeezing property is provided. That is, according to the present invention, the entire bottle is made of a resin having low rigidity, and only the front surface wall and / or the back wall having a large area is formed by the in-mold labeling method using a resin having higher rigidity than that, or The front surface wall and / or back surface wall of a large area and the side surface habit of a small area are composed of two types of resins with different rigidity, and the front surface wall and / or back surface wall of a large area are made rigid by the in-mold label method. Is added.

The flat bottle of the present invention has a self-supporting property because a label made of a relatively rigid film is inserted on the inner surface of the front surface wall and / or the rear surface wall by the in-mold label method. It forms a wall surface, and its side surface is composed only of low-rigidity resin such as low-density polyethylene that is highly flexible and does not have self-supporting properties. Even if the contents are discharged, that part will not be deformed, but the side wall will be deformed by it, and the shape will be maintained even after the contents are discharged. In other words, the flat bottle of the present invention has an excellent squeeze property and does not cause an air bag phenomenon after the contents are discharged. Therefore, it is possible to prevent the remaining contents from contacting air and oxidizing. You can

Further, according to the present invention, since the front surface wall and / or the rear surface wall is formed by the in-mold label method as described above, the inserted label or blank is not included in the front surface wall and / or the back wall. Alternatively, the rigidity of the back wall can be increased to form a self-supporting wall surface with a small amount of resin, and at the same time as the molding, a printing indication by an in-mold label or a decorative pattern, etc. is formed on the inner surface on the front side and / or the back side of the bottle. It can be applied and the printed markings or decorative patterns can be seen through the surface of the bottle.

The in-mold label method is a method in which a label or a blank is inserted into a mold in advance and is bonded at the same time as molding. In the present invention, the maximum purpose of inserting the label or blank on the front surface wall and / or the rear surface wall by the in-mold labeling method is, as described above, that the front surface wall and / or the rear surface wall is self-supporting. In order to achieve this purpose, the label or blank does not necessarily have to be printed, and in this case, the bottle can be formed as an opaque one. However, the surface of the bottle is usually printed or patterned to enhance the commercial value, and the flat bottle of the present invention is no exception.

The features of the in-mold label method are that, in addition to imparting rigidity to the bottle described above and reducing the amount of molding resin, the label can be adhered over the entire surface, and there is no protrusion at the end of the label, and there is no catching. It doesn't peel off because it doesn't exist.・ Because gravure is printed on the label or blank in advance, it is possible to express multicolored colorful prints and delicate lines. (Printing on the surface of a molded product has its own limitations due to printing technology. It is difficult to print delicate lines and small characters). -In particular, in the case of a bottle for the purpose of squeezing as in the present invention, it is difficult to cause wrinkles on the label.

In the flat bottle of the present invention, the front wall and / or back wall of the large area is formed by the in-mold labeling method of high density polyethylene, and the side wall of the small area is low density polyethylene, ethylene-vinyl acetate. An example constituted by a copolymer or a linear low density polyethylene will be described. In FIG. 1, which is a side sectional view of a flat bottle of the present invention (generally indicated by A), an in-mold label 2 is formed so as to be inserted into a front surface wall 1 and / or a rear surface wall 1 '. In Fig. 2 for explaining the procedure for molding a flat bottle by the in-mold label method, and Fig. 3 showing the cross-section of the label structure, the plastic constituting the label base layer 7 is a high-density container constituting the main body. The same resin as polyethylene is preferably used, but other than that, for example, crystalline polypropylene, crystalline propylene-ethylene copolymer, crystalline polybutene-1, crystalline poly-4-methylpentene-1, low -Or, polyolefins such as medium density polyethylene are used.

Taking the case of printing on a label as an example, the plastic constituting the label base layer 7 is usually a uniaxially or biaxially stretched transparent material, and the transparent film is passed through the transparent film to be printed on the back surface thereof. You will see the printed layer 8 formed. The thickness of the stretched film is preferably 20 to 300 μm, particularly 60 to 100 μm. If not printed on the label, both the label and the bottle may be made of opaque material. Further, as the label base layer, one obtained by subjecting the above plastic base layer to aluminum vapor deposition or one laminated with an aluminum foil may be used.

The printing layer 8 is a so-called back surface printed with printing ink, and may be a multiple printing layer like the image part and the background, or the background layer may be a metal vapor deposition layer. The printing layer 8 can be formed by a method known per se, for example, letterpress printing, intaglio printing, gravure printing, planographic or offset printing, silk screen printing, thermal transfer printing, electrophotographic printing, and the like, and the overcoat layer. Can be formed using a solution of a resin having excellent transparency such as an acrylic resin, a vinyl chloride resin, or a cellulose derivative. The label to be inserted into the flat bottle of the present invention may have a layer of hot melt adhesive on the printing ink layer or a label base layer as needed in order to favorably form an in-mold label. An overcoat layer made of a releasing material can be formed on the upper surface of the.

In FIG. 2, a label 2 made of a plastic film having a printed layer formed on the inner surface side thereof is provided on at least one cavity surface 3 of the blow split molds 6a, 6b prior to molding the plastic parison blow. Apply (step A). FIG. 2 shows an example of forming an in-mold label on only one side of the bottle. If this is to be formed on both sides, a similar in-mold label forming part can be formed on the blow split mold 6b side. Good. That is, there is a portion for supporting the label 2 on the cavity surface 3, and the depressurization suction mechanism 4 is provided in this portion, and the label 2 is adsorbed by a label insertion device (not shown) called an inserter. While being supplied and held on the cavity surface 3. In this case, the label 2 has a positional relationship in which the plastic film base layer 7 is on the outside and the printing layer 8 is on the inside. The application and fixing of the label 2 to the cavity surface 4 can be performed not only by the suction method but also by static electricity, for example. On the upper part of the blow split mold, a coextrusion device 9 having two dies is arranged.

Next, in step B, high-density polyethylene forming the front and back walls and low-density polyethylene, ethylene-vinyl acetate copolymer or linear low-density polyethylene forming the side walls are coextruded from the two dies. Then, one parison is formed from two kinds of resins, and the parison is supplied so that the label is formed on the high-density polyethylene side. Then, the blow split molds 6a and 6b are closed, and pressurized gas is blown into the closed parison 5. In step C, the expanding parison in the mold is retained on the mold surface and the label 2 is combined with the high density polyethylene part of the expanded parison, cooled in contact with the mold surface and the printed label is displayed. It becomes a flat bottle.

The size of the label used for in-molding may be such that the front surface and / or the back surface of the bottle can be rigid enough to have a shape-retaining property (self-supporting property). It may be formed in the vicinity of the bottom of the bottle surface by about 30 to 80%. The high-density polyethylene that constitutes the front and back walls of the bottle is not particularly limited, but is a homopolymer of ethylene having a density of 0.940 to 0.965 g / cm ³ , and a small amount of ethylene and a small amount of ethylene. A copolymer with an α-olefin is used, and particularly, high density polyethylene having a density of 0.945 to 0.960 g / cm ³ is preferably used. The resin forming the side wall of the bottle has a relatively low rigidity such as low density polyethylene having a density of 0.915 to 0.930 g / cm ³ , ethylene-vinyl acetate copolymer or linear low density polyethylene. Among these, low density polyethylene having a density of 0.918 to 0.925 g / cm ³ and ethylene-vinyl acetate copolymer having a vinyl acetate content of 3 to 10% by weight are preferably used. . It should be noted that when the entire bottle is made of a resin having low rigidity, the resin forming the side wall is used, and the wall configuration by the in-mold label method is the same as that described above. There is no end.

[0018]

[Effect of the device]

 According to the present invention, there is provided a bottomed flat bottle in which the front surface wall and / or the rear surface wall is configured as a self-supporting wall surface having relatively rigidity, and the side wall is configured as a soft and non-restoring wall surface. Although this bottle is self-supporting as a whole, it has no squeeze property because it does not have an air bag property after discharging the contents, and it is crushed at the time of disposal after use. Therefore, the volume can be made significantly smaller than that of the conventional plastic bottle, and the space-saving flat bottle can be easily disposed.

[Brief description of drawings]

FIG. 1 is a side sectional view of a flat bottle of the present invention.

FIG. 2 is a view for explaining an in-mold label method used to mold the flat bottle of the present invention.

FIG. 3 is a cross-sectional view showing an example of a layer structure of a label inserted in the surface wall of the flat bottle of the present invention.

[Explanation of symbols]

 1 Flat Bottle Front Wall 1'Flat Bottle Rear Wall 2 Label 3 Cavity Surface 4 Decompression Intake Mechanism 5 Parison 6a Blow Split Mold 6b Blow Split Mold 7 Label Base Layer 8 Printing Layer 9 Coextrusion Device

Claims (4)

[Scope of utility model registration request] 1. A flat bottomed bottle, wherein the entire bottle is formed of a thermoplastic resin having a low rigidity, and a large-area surface wall and / or back surface wall of the bottle has a rigidity higher than that of the bottle-forming resin. A flat bottle made of plastic with excellent squeeze characteristics, which is characterized by being formed by an in-mold label method using a thermoplastic resin. 2. The flat bottle according to claim 1, wherein the low-rigidity thermoplastic resin is selected from the group consisting of low-density polyethylene, ethylene-vinyl acetate copolymer, and linear low-density polyethylene. . 3. The flat bottle according to claim 1, wherein the high-rigidity thermoplastic resin is high-density polyethylene. 4. A bottomed flat bottle obtained by co-extruding a plurality of synthetic resins, wherein a large-area front surface wall and / or back surface wall is formed by a high-density polyethylene in-mold label method, and a small-area side surface. A flat bottle made of plastic having excellent squeeze properties, characterized in that the wall is made of low-density polyethylene, ethylene-vinyl acetate copolymer or linear low-density polyethylene.