JPH0653127U - Blow molding container - Google Patents

Abstract

(57) [Summary] [Objective] To provide a foldable blow-molded container having a standing property and a squeeze property. [Structure] A container having a single-layer or multi-layer structure obtained by blow molding a thermoplastic resin material, in which the horizontal cross-sectional shape of the body is elliptical or egg-shaped, and one of the maximum lengths at one end in the longitudinal direction is the maximum. A thick wall portion having a wall thickness (thickness a) and a thin wall portion having a minimum wall thickness (thickness b) provided at the other end, and one thick wall portion to the other thin wall portion along the periphery of the body portion. The thickness distribution of the uneven thickness structure in which the thickness continuously changes, the thickness ratio a / b is in the range of 1.3 to 5.0, the thickness of the body Is in the range of 100 to 1500 μm, and the bottom has a flat bottom.

Description

[Detailed description of the device]

[0001]

[Industrial applications]

 The present invention relates to a thin-film container manufactured by blow molding from a thermoplastic resin material, and more specifically, a collapsible blow molding having standing (self-supporting) and squeeze (crushing) properties. Regarding the container.

[0002]

[Prior art]

 Recently, foldable plastic containers have been receiving attention. By adding a folding function to the plastic container, it is possible to reduce the transport capacity when supplying the container, reduce the amount of waste by reducing the wall thickness, and reduce the cost.

Conventionally, blow molding containers (bottles) that are soft and have a squeeze property are widely used as containers for ketchup, mayonnaise, and the like. However, conventionally known squeeze bottles have a drawback that the standing property is insufficient even when the contents are completely filled, and the standing property is lost when the contents are reduced.

As a foldable container having a standing property, a standing pouch having a structure in which films are stuck together is also known, and is used, for example, as a container for refilling detergent and the like. However, the conventionally known standing pouches have problems that the process of injecting the content into the container is troublesome, that the standing property is insufficient, and that the contents easily overflow when refilling into another container. There is. Standing pouches with various openings have been put on the market in order to prevent the contents from overflowing when refilling, but the difficulty of handling has not been solved because the entire container is too flexible.

As a folding bottle, a blow molding bottle with a folding line has been proposed. Conventionally known foldable bottles have a flat bottom design or a thicker half meniscus at the bottom to provide standing, but their independence is still insufficient or a balance between standing and squeeze. Is not enough.

[0006]

[Problems to be solved by the device]

 An object of the present invention is to provide a foldable blow molded container having standing and squeezing properties. As a result of earnest research to overcome the above-mentioned problems of the prior art, the present inventor provided a special uneven thickness distribution in the body of a blow molding container made of a thermoplastic resin material. We found that a foldable blow-molded container with improved standing and good squeeze was obtained, and based on this finding, we completed the present invention.

[0007]

[Means for Solving the Problems]

 Thus, according to the present invention, there is provided a container having a single-layer or multi-layer structure obtained by blow molding a thermoplastic resin material, wherein (1) the horizontal cross-sectional shape of the body is oval or oval. A thick portion having the maximum thickness (thickness a) is provided at one end in the major axis direction, and a thin portion having the minimum thickness (thickness b) is provided at the other end, and one is provided along the periphery of the body portion. The thickness distribution has a non-uniform thickness structure in which the thickness continuously changes from the thick portion to the other thin portion, (2) The thickness ratio a / b is 1.3 to 5.0. (3) The thickness of the body is in the range of 100 to 1500 μm, and (4) the bottom is a flat bottom.

The blow-molded container of the present invention is formed of a thin film as a whole and has a special thickness distribution in the body part, so that it has both standing property and squeeze property and can be easily folded. it can. Hereinafter, the blow molding container of the present invention will be described with reference to the drawings.

FIG. 1 is a side view of one embodiment of the blow molding container of the present invention, FIG. 2 is a side view seen from the other side, and FIG. 3 is a bottom view. FIG. 4 is a schematic diagram for explaining the horizontal cross-sectional shape of the body of the blow molding container of the present invention.

In the blow-molded container (1) of the present invention, as is apparent from these drawings, particularly FIGS. 3 and 4, the horizontal cross section of the container body has an elliptical or oval shape. The bottom (3) of the container is also oval or egg-shaped and flat (flat bottom). In the blow-molded container of this example, the bottom portion of the container has a projection portion (8) and a recessed portion (7) formed by pinch-off during blow molding, but these are merely design matters. For example, it does not matter if there is no recessed portion. The bottom of the container should be substantially flat and should have a structure that ensures standing. Further, in the blow-molded container of this embodiment, the spout (2) with a screw is formed, but instead of this, for example, the upper part of the container body is cut to form an opening, and the contents are After injection, the opening may be heat-sealed.

As shown in FIG. 4, the blow-molded container of the present invention has a body having an oval or oval horizontal cross-section, and has a maximum wall thickness (thickness a) at one end in the longitudinal direction (9). ), And a thin portion having the minimum thickness (thickness b) is provided at the other end. Then, along the periphery of the body portion, there is a wall thickness distribution with an uneven wall thickness structure in which the wall thickness continuously changes from one thick wall portion (A side) to the other thin wall portion (B side). ing.

The blow-molded container of the present invention not only has a flat bottom structure but also has a thick portion (A side), so that the standing property is improved. Further, the thick portion maintains the strength of the container and facilitates the shape recovery of the folded container. On the other hand, the thin portion (B side) ensures the squeeze property, and the body portion can be easily folded by crushing it in the minor axis direction of the elliptical or oval shape. Further, by squeezing the thin-walled side of the blow-molded container filled with the content part, the outflow of the contents can be facilitated. The bottom and shoulders can be folded to the side of the body after crushing the body.

The wall thickness of the body is in the range of 100 to 1500 μm. That is, it is necessary for the thin portion to have a thickness of at least 100 μm or more. If the thickness is too thin, it is difficult to maintain strength, and it is necessary to stably form an uneven thickness distribution structure by blow molding. Becomes difficult. The thick portion has a thickness of 1500 μm or less. If the thickness of the thick part is too large, the squeeze property will be impaired. The thickness of the body is preferably 150 to 1000 μm.

The ratio a / b between the maximum wall thickness (thickness a) and the minimum wall thickness (thickness b) is 1.3 to 5. It must be in the range of 0. If this wall thickness ratio is too small or, on the contrary, too large, the balance between the standing property and the squeeze property becomes poor, and blow molding becomes difficult. The wall thickness ratio a / b is preferably 1.5 to 3.0. The wall thickness ratio a / b is measured by dividing the body of the blow molding container into 17 equal parts in the horizontal direction at substantially equal intervals and measuring the maximum wall thickness on the A side and the minimum wall thickness on the B side of each horizontal section. However, it is the average wall thickness ratio obtained by calculating the value of each ratio and averaging those values. The maximum thickness (a) is usually 300 to 1500 μm, preferably 400 to 600 μm, and the minimum thickness (b) is usually 100 to 600 μm, preferably 150 to 400 μm. is there.

The blow molded container of the present invention can be formed by blow molding using a thermoplastic resin material. In blow molding, generally, a tubular parison is melt extruded between molds opened from an extruder, then the mold is closed and the lower part of the parison is pinched off and fused, and then inside the parison. Blows in by blowing air. After cooling, the mold is opened and the molded product is taken out.

Conventionally, in the case of producing a bottle by blow molding, in order to obtain a highly accurate molded product with less uneven thickness, the molten parison from the extruder is inserted into the barrel (bottom of the bottle) inside the split mold of the molding machine. It was extruded to the center of the part that forms the part). On the other hand, in order to create the blow-molded container of the present invention, a mold having an oval or oval cross section is used, and the molten parison from the extruder is used in the mold. Instead of pushing it to the center of the body, push it to an eccentric position.

That is, the parison is on the parting line of the split mold and is in a direction (thick part: A side) opposite to the side (thin part: B side) that is thinned to give squeeze property. ), Shift the center position and extrude. By eccentricizing the extruding position of the molten parison, it is possible to form a body having a thickness distribution with a special uneven thickness structure. In other words, when air is blown into the parison for blow molding, the parison expands along the inner diameter of the body of the mold, but because the position of the parison is eccentric from the center, the parison of the obtained container is The film thickness is not uniform, and the wall thickness is larger in the portion closer to the parison lowering position (extrusion position), and conversely, in the portion farther to the parison lowering position, the wall thickness is unevenly formed.

In the embodiment shown in FIGS. 2 to 4, reference numeral (9) represents a parting line of the mold, which also corresponds to the elliptical or oval major axis of the horizontal cross-section of the body. Suru Reference numeral (6) in FIG. 1 indicates the lowered position of the molten parison. By adopting such a blow molding method, as shown in the horizontal cross-sectional shape in FIG. 4, a special uneven thickness distribution is formed in the wall thickness of the body (11).

The blow molded container of the present invention may be provided with reinforcing ribs if desired. The shape and the number of reinforcing ribs can be appropriately determined. 5 to 7 show one embodiment of a blow molding container having ribs (4 and 5) formed thereon. In this embodiment, the ribs are provided at both ends of the A side and the B side, but in particular, when a plurality of ribs are provided along the longitudinal direction of the body portion on the thin portion side (B side side), the reinforcing effect is obtained. Is remarkable.

The wall thickness distribution of the body of the blow-molded container of the present invention may be uniform in the vertical direction, but as shown in FIG. 8, the wall thickness may vary gently in the vertical direction. The blow-molded container of the present invention may be a single layer made of one kind of thermoplastic resin material, but a plurality of thermoplastic resin materials may be used for the purpose of imparting gas barrier property, coloring, and heat resistance. It may be a multi-layer structure using. To obtain a multi-layer structure, a multi-layer blow molding method may be adopted and a multi-layer parison may be molded.

Examples of the thermoplastic resin material constituting the blow molded container of the present invention include homopolymers and copolymers of polypropylene, low density polyethylene, medium density polyethylene, linear ethylene / α-olefin copolymers (LLDPE, VLDPE). , ULDPE, etc.), polyolefins made with metallocene (single-site / Kaminsky) catalysts, etc. Other ethylene resins and the like are not limited to the above resins as long as they do not impair the moldability and squeeze property. Further, it may be a blend of two or more kinds of the resins exemplified above.

When the blow-molded container of the present invention has a multi-layered structure, for example, low density polyethylene is used as the inner and outer layers, and a gas barrier ethylene / ethylene layer is used as a core layer with an adhesive layer between these resin layers. Examples thereof include those in which a vinyl alcohol copolymer (EVOH) is arranged. As the gas barrier resin, in addition to EVOH resin having an ethylene content of 20 to 50 mol%, known physical gas barrier materials such as MXD-6 nylon and nitrile resins such as Barex, oxygen absorbing polymers and other chemicals A suitable gas barrier material is appropriately used. A resin layer containing regrind may be provided.

In the case of a multi-layer structure, if sufficient adhesion cannot be obtained between the inner layer or outer layer and the middle layer such as the core layer or the regrind layer, an adhesive resin layer is provided between these layers. . The adhesive resin layer in this case is, for example, an acid-modified polyolefin resin, for example, polyethylene graft-modified with an ethylene-based unsaturated carboxylic acid such as maleic anhydride, acrylic acid, methacrylic acid, or itaconic anhydride, or an anhydride thereof. And polypropylene are preferably used.

The blow-molded container of the present invention can be folded, and the bulkiness of the three-dimensional container can be eliminated by flatly folding the empty container during transportation or after use. Further, since the blow-molded container of the present invention has a three-dimensional shape when filling the contents, the filling operation is easy. When the contents flow out, the shape is maintained by being strengthened by the thick-walled part, so it does not overflow, and the thin-walled part is squeezed to facilitate the outflow. be able to. In addition, the presence of the thick wall portion improves the standing property.

[0025]

【Example】

 Hereinafter, the present invention will be described with reference to examples.

Example 1 A blow molding container in which the horizontal cross section of the body as shown in FIG. 1 has an oval shape using a plurality of extruders and a mold in which the descending position of the parison is eccentric. It was created. The capacity of the container was 850 cc, and the basis weight was 36 g. The layer structure of the container is outer layer / adhesive layer / EVOH / adhesive layer / regrind layer / inner layer. Low density polyethylene (LDPE: F 114-1) manufactured by Sumitomo Chemical Co., Ltd. is used for the inner and outer layers, and EVOH resin (EP-F 101 AZ) manufactured by Kuraray Co., Ltd. is used for the core layer. The acid-modified PE (Admer) manufactured by Mitsui Petrochemical Co., Ltd. was used as the material. The result of the wall thickness measurement of the container of this example shows the wall thickness distribution as shown in FIG. 8, and the average wall thickness ratio (a / b) on both sides A and B of the parting line in the body Was about 2.0, and the average thickness difference between both sides was about 350 μm. The thick side (A side) contributes to the self-supporting property of the container, and the thin side (B side) contributes to the squeeze property. And the obtained container was foldable.

Example 2 In the same manner as in Example 1, a blow-molded container having a capacity of 850 cc and a basis weight of 20 g was prepared with the same laminated structure. The thickness of the body of the obtained blow-molded container is about 200 to about 300 μm on the thin side (B side) and about 380 to about 490 μm on the thick side (A side), and the thickness difference between both sides is , About 140 to about 250 μm (average about 170 μm). The thickness ratio on both sides was in the range of about 1.5 to about 2.1, and the average wall thickness ratio (a / b) was about 1.7. This blow-molded container had a good standing property, a squeeze property, and was foldable.

[0028]

[Effect of device]

 According to the present invention, it has become possible to impart squeezeability, as well as standing and foldability, to a squeeze blow molding container, which has been hitherto lacking in independence. Further, the blow-molded container of the present invention can also be a standing pouch with a cap having a spout formed by blow molding. The bulkiness of the conventional blow-molded container can be eliminated by folding it during transportation or after use.

[Brief description of drawings]

FIG. 1 is a side view of a blow molding container made according to an embodiment of the present invention.

FIG. 2 is a side view of a blow molding container made according to an embodiment of the present invention.

FIG. 3 is a bottom view of a blow molding container made according to an embodiment of the present invention.

FIG. 4 is a horizontal cross-sectional view of a body of a blow molding container made according to an embodiment of the present invention.

FIG. 5 is a side view of a blow-molded container with ribs made according to an embodiment of the present invention.

FIG. 6 is a side view of a blow molding container with ribs made according to an embodiment of the present invention.

FIG. 7 is a bottom view of a rib-molded blow-molded container made according to an embodiment of the present invention.

FIG. 8 is a longitudinal wall thickness distribution of a body of a blow-molded container manufactured according to an embodiment of the present invention.

[Explanation of symbols]

1: Blow-molded container body 2: Mouth part (pouring mouth with screw) 3: Bottom part 4: Rib 5: Rib 6: Parison descent position 7: Bottom recessed part 8: Pinch off part 9: Mold parting line (oval shape) Or the long axis of the egg shape) 11: wall thickness of the body a: maximum wall thickness b: minimum wall thickness A side: thick wall portion B side: thin wall portion

Claims (1)

[Scope of utility model registration request] 1. A container having a single-layer or multi-layer structure obtained by blow-molding a thermoplastic resin material, wherein (1) the body has a horizontal cross-sectional shape of an ellipse or an egg, and its longitudinal direction. A thick part having a maximum wall thickness (thickness a) at one end and a thin wall part having a minimum wall thickness (thickness b) at the other end, and one thick wall part along the periphery of the body part From one to the other thin portion, the thickness distribution has an uneven thickness structure in which the thickness continuously changes. (2) The thickness ratio a / b is in the range of 1.3 to 5.0. The blow-molded container is characterized in that (3) the thickness of the body is in the range of 100 to 1500 μm, and (4) the bottom is a flat bottom.