JPH10119118A - Containerlike double walled blow-molded article - Google Patents

Abstract

PROBLEM TO BE SOLVED: To exhibit excellent compression resistance and impact resistance by a constitution wherein approximately uniform thickness is provided on the outer peripheral side walls and a bottom and ridge parts thereof and as recessed parts or projected parts are formed on the outer peripheral side walls, it is extremely tough and no stress concn. occurs at a part when impact loading is applied by compression loading and falling down. SOLUTION: An opening part has a cylindrical container shape consisting of a polygonal, cylindrical, ellipsoidal and uncertain shapes and dimensional ratio of the depth of the outer peripheral side wall 11 to the square root of the area of the opening outer shape part is made 0.5 to 3. On the outer peripheral side walls 11 among peripheral side walls, deep recessed parts 10 being close to the inner peripheral side walls 15 or projected parts 10a projected outside are provided for hand hooking parts during delivering and the thickness of the outer peripheral side walls, a bottom sheet and ridge parts on these boundaries are prepd. by blow molding from a single parison with an approximately uniform thickness.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an integrated hollow molding having a deep-walled double-wall structure used for a cold storage container or a cold storage container such as an ice box or a ribbed container or a bathtub for a special industrial part. About goods.

[0002]

2. Description of the Related Art A conventional product having a double-walled structure is a method in which an inner wall and an outer wall are formed by injection molding and then joined by secondary processing such as ultrasonic bonding or heat fusion. -14152, and a double wall blow molding method based on a blow molding method described in JP-A-54-44983. These products are used for musical instrument cases and attache cases.

[0003]

However, although the product obtained by the former method is a hollow product with a deep double wall, the inner wall and the outer wall are individually formed and then joined by secondary processing. Therefore, there are problems of peeling of the joint surface and strength. Also, if a rib structure is to be attached to improve the strength and rigidity of the product, the mold becomes complicated and the moldability is inevitably deteriorated. Therefore, a range with a small molecular weight and good fluidity must be used. Therefore, on the contrary, physical properties such as impact strength and environmental stress crack resistance are reduced. On the other hand, when a single resin is used, the product obtained by the latter method tends to have a non-uniform thickness, and particularly the ridges and corners between the peripheral wall and the bottom of the outer wall become extremely thin, and the rigidity and I am worried about strength. For this reason, it is possible to cope by blending with a resin having good elongation, but it is still impossible to perform deep drawing, and the drawing depth by this method is such that when the opening is a square, the depth is one side of the opening. Currently, it is set to 0.5 or less, and products having a rib structure or the like cannot be extracted from a mold, and thus cannot be manufactured at all conventionally. Looking at the current situation as above,
As a result of diligent studies, the inventors of the present application have found a deep drawing product having a double structure with excellent impact strength and compressive strength, and have completed the present invention.

[0004]

In order to achieve the above object, the present invention provides a cylindrical container having an opening formed of a group of polygonal, cylindrical, elliptical, and irregular shapes. The ratio of the depth of the outer wall to the square root of the area is 0.5
And at least one of the outer peripheral side walls is provided with at least one deep concave portion or an outwardly protruding protruding portion approaching the inner peripheral side wall as a handle portion during transportation. The thickness of the peripheral side wall and the bottom plate and the thickness of the boundary ridge portion thereof are almost uniform and are formed by blow molding from a single parison. .

In order to achieve the above object, the container-shaped double-walled hollow blow-molded article is characterized in that:
In some cases, the thickness of the bottom plate and the boundary ridge portion thereof is thicker than the inner peripheral side wall. In this specification, the term “single parison” includes not only a homogeneous single-layer parison, but also heterogeneous inner and outer parisons of two or more layers, and a heterogeneous or different-color parison by half along an axial line. . The material to be used is not particularly limited as long as it can be blow-molded. For example, polyolefins such as polyethylene and polypropylene, EV
A, polyvinyl chloride, a copolymer of one of these with another resin, an engineering plastic, and the like. Further, the polygonal shape means a triangular or octagonal shape. The invention shown in claim 1 and the inventions of other claims which are configured as described above are used as an ice box, a container for keeping cool, a relatively large container, a container for loading heavy objects, and a bathtub. The concave portion or the portion protruding outward is used as a handle portion during transportation. The method according to claim 2 is used in particular for heavy loads.

[0006]

DESCRIPTION OF THE PREFERRED EMBODIMENTS Hereinafter, the present invention will be described in more detail by way of examples, but the present invention is not limited thereto. Embodiment 1 This embodiment is a representative embodiment of the first and second aspects of the present invention. 1, 2, and 3, using high-density polyethylene (trade name “Nipolon Hard 8300A” manufactured by Tosoh Corporation)
According to the manufacturing method described in JP-A-67130, a rectangular parallelepiped having an opening was integrally hollow-molded. The outline of the manufacturing method will be described below. First, a pair of male and female molds was used as a mold, and a male mold was used which was a double mold and whose protruding portion was able to come and go. On the other hand, the female mold is composed of a bottom mold and a divided mold divided for each side wall surface, and the bottom mold and the side divided molds are substantially parallel to the ridge at the positions of the ridges forming the respective boundaries. The one in which each split mold was opened outward by a pivot was used. Thus, in the manufacturing method, each split mold of the female mold is spread outward, while the protrusion of the male mold is retracted, and the male and female molds are separated from each other, A single parison is supplied between these male and female molds, and after closing the tip, the parison is inflated to an extent corresponding to the surface area required for the molded article, and then each split mold of the female mold is kept open. The male and female molds are approached to flatten the parison, and then, while adjusting the parison internal pressure, gradually raise the split molds of the female mold so that the parison also comes into contact with the inner surface of each split mold. Then, the entire parison is deformed so as to cover the male mold, and an extra parison between the divided molds is sandwiched between the divided molds, and cut off as necessary.

Next, the male and female molds are closed while further adjusting the inner pressure of the parison, and the excess parison is sandwiched between the male and female molds and is also cut off. Next, the protruding portion of the male mold is advanced to a predetermined position in the female mold, and finally the parison internal pressure is increased to expand the parison to a cavity shape formed by the inner surfaces of the male and female molds, and after cooling and solidification, the mold is removed. A molded product was obtained. However, a female mold that had been subjected to undercut processing for each of the divided molds was used. The size of the outer shape of the molded product is the length a =
180 mm, width b = 165 mm, height (depth) c = 13
0 mm, the size of the inner part of the opening is 140 mm in length,
The width was 147 mm and the height was 120 mm. Also, 114mm x 97mm x
The 35 mm (depth) undercut of the recess 10 and the protrusion 10a were applied as a handle for transportation. The area outside the opening of this molded product is A = a × b, and the depth is c.
Therefore, the aperture ratio R referred to in this specification is R = c / √A = 0.75 in the above-described example.

In addition, reference numeral 11 in the figure denotes an outer peripheral side wall, 1
2 is the outer bottom, 13 is the bottom ridgeline that bounds these, 14
Is a vertical ridgeline that forms a boundary between outer peripheral side walls, 15 is an inner peripheral side wall, 16 is an inner bottom, and 17 is an inner bottom ridgeline that forms a boundary with the inner peripheral side wall 15. A concave portion 10 is provided on the outer peripheral side wall 11 so as to approach, and the depth of the concave portion 10 is 5 mm from the outer surface. The moldability, thickness distribution, compressive strength, and low-temperature drop test of this one-piece hollow molded product were performed. The thickness distribution was measured with calipers at the locations shown in FIG. However, point e is the outer peripheral side wall 11
Point h is a part of a ridge line 14 between the inner bottom wall 16 and the inner bottom 16, and a point h is a part of a ridge line 14 between the inner bottom wall 16 and the inner bottom 16.
Points g and i are points 1 cm away from each ridge line. or,
The compressive strength was measured in accordance with JIS Z0212-87 "Compression test method for packaged cargo and containers", and the low-temperature drop test was performed by diagonally dropping 10 molded articles from a height of 2 m at -20 ° C. The number of breaks at that time was measured. Table 1 shows the results.

Example 2 A molding was performed in the same manner as in Example 1 except that the drawing ratio was changed to 1.2. The result is

[Table 1] Shown in

Example 3 An integrated hollow molded article was produced in the same manner as in Example 1 except that a rib structure in the depth direction was provided on the undercut portion. The result

The results are shown in Table 1. Comparative Example 1 Using high-density polyethylene (trade name “Nipolon Hard 8300A” manufactured by Tosoh Corporation),
No. 152 by the method described in JP-A-152 (described later).
An attempt was made to produce an integral hollow molded product having a square opening 5 with an integrated female mold, but a pinhole was formed at the ridge line toward the bottom surface of the inner wall, and molding was not possible. Comparative Example 2 A high-density polyethylene (manufactured by Tosoh Corporation, trade name “Nipolon Hard 8300A”) and polypropylene were used in a ratio of 1: 1.
Using the composition mixed in the above, an integrated hollow molded product having a drawing ratio of 0.5 was prepared according to Japanese Patent Publication No. 46-14152. The outline of the manufacturing method is that the male mold has a protruding part
The female mold is an integral part. First, a slightly flat parison is supplied between the male and female molds, and then the entire parison is clamped by the partial mold around the male mold and the female mold. The double-wall hollow blow-molded product was formed by adjusting the protrusion of the male mold so as to project to a predetermined position in the female mold. The result

The results are shown in Table 1. It is not limited to what is shown in each embodiment,
Other shapes such as deep-drawn containers such as polygonal cylinders, cylinders, and elliptical cylinders, and irregular shapes such as flat gourds and rice balls may be used, and the purpose of use is limited to containers, bathtubs, and heat-insulated containers. Alternatively, other industrial tanks or automobile parts may be used.

[0011]

[Table 1]

[0012]

According to the first aspect of the present invention, the apparatus is constructed and operates as described above.
In the described invention, in particular, the outer peripheral side wall and the bottom, as well as these ridges, have a substantially uniform wall thickness, and the outer peripheral side wall is formed with the concave portion or the protruding portion. So it ’s extremely durable,

As shown in Table 1, even under a compressive load and an impact load caused by a drop, stress is not partially concentrated, and exhibits excellent compression resistance and impact resistance. It can withstand heavy objects and bathtubs. In addition, since it has an unprecedented deep drawing shape, it is possible to store a tall packaged object. In the case where a lateral recess or projection is formed in the peripheral side wall, particularly in the middle portion thereof, it serves as a handle for transportation and facilitates transportation in the case of a large container. According to the second aspect, in addition to the above effects, the outer peripheral side wall and the bottom are formed thicker than the inner peripheral side wall.
Because it is strong against impact, the inner peripheral side wall is thin, so it is more easily elastically deformed than the outer peripheral side wall and the bottom, and it exhibits a buffer effect in combination with the intermediate air layer, and the load by the packaged object is received as a tensile load There is no buckling problem.

When the aperture ratio R is not more than 0.5, the thickness distribution is somewhat irregular, or even if there is no undercut, there is little effect in practical use, and the aperture ratio R is 3 or more. This means that the split mold for manufacturing may be too elongated, and the thickness of the inner peripheral side wall of the molded product may be too thin, which is not practical. Examples 1 to 3
As shown in the column of low temperature drop in the table, there was no breakage at all, and there was a marked difference in the effect from that of 8 out of 10 breakage as shown in the comparative example. . When the parison is formed from a material having a foamed layer in a layer other than the outermost layer, the heat insulation and cushioning effects are further enhanced. Alternatively, a target substance such as foamed polyurethane can be filled between the double walls of the molded article to further enhance its performance.

[Brief description of the drawings]

FIG. 1 is an overall perspective view.

FIG. 2 is a partially longitudinal side view of Example 1.

FIG. 3 is a cross-sectional plan view of a ridge line portion.

[Explanation of symbols]

 REFERENCE SIGNS LIST 10 concave portion 10 a projecting portion 11 outer peripheral side wall 12 outer bottom 13 bottom ridgeline portion 14 vertical ridgeline portion 15 inner peripheral side wall 16 inner bottom

──────────────────────────────────────────────────の Continued on the front page (51) Int.Cl. ⁶ Identification code FI B65D 1/02 B65D 1/02 C 81/38 81/38 E F25D 3/02 F25D 3/02 // F25D 3/14 F25D 3 / 14 B29L 22:00 24:00 (72) Inventor Shoro Sawayama Yokkaichi City, Mie Prefecture, also known as 6-8-20

Claims (2)

[Claims] An opening has a cylindrical container shape composed of a group of polygonal, cylindrical, elliptical, and irregular shapes, and a dimensional ratio of a depth of an outer wall to a square root of an area of the outer shape of the opening. 0.5 to 3, and at least one of the outer peripheral side walls of the outer peripheral side walls is provided with a deep recessed portion or an outwardly protruding protruding portion approaching the inner peripheral side wall as a handle portion during transportation. A container-shaped double-walled hollow blow-molded article characterized in that the outer peripheral side wall, the bottom plate and the boundary ridge portion thereof are blow-molded from a single parison having a substantially uniform thickness. 2. The container-shaped secondary battery according to claim 1, wherein the outer peripheral side wall, the bottom plate, and the boundary ridge portion thereof have a greater thickness than the inner peripheral side wall. Heavy wall hollow blow molded product.