JPH0249981B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of Industrial Application] The present invention consists of a main body and a lid, and a compressed thin hinge that connects the main body and the lid together, and is made of a single plastic material. This invention relates to a plastic container manufactured by blow molding, which has a parting line formed by sandwiching a parison made of plasticized plastic material around the entire circumference of the container.

[Prior Art] Conventionally, a device has been constructed of a single plastic material, consisting of a main body and a lid, and a compressed thin hinge that integrally connects the main body and the lid. A plastic container manufactured by blow molding having a parting line formed by sandwiching a parison throughout the container is known as shown in Japanese Patent Publication No. 18748/1983.

[Problems to be Solved by the Invention] However, conventional blow-molded plastic containers have the following drawbacks. That is, as shown in FIG. 12, the hinge base 58 located at the parting line during blow molding is configured on the same line as the mating surface 56 of the container, so that excessive stress is not applied to the hinge 54 when the container is used. In addition, since the hinge width from the hinge base 58 on the main body 52 side to the hinge base 58' on the lid body 53 side is formed small, the hinge strength is poor, especially when the hinge is made of polyolefin plastic material such as polyethylene. This drawback is particularly noticeable in containers that have been used for a long time. Due to the above-mentioned factors, conventional containers have poor repeat bending characteristics of the hinge, and the life of the container itself has been shortened.

The applicant, as a means to solve the above deficiencies,
As shown in FIG. 13, the idea was to form the hinge 64 with a large width, but even if the hinge 64 is simply formed in this way, there will be a gap between the mating surfaces 66 of the container when the main body 62 and the lid 63 are closed. This resulted in a container with poor protection for stored items. Therefore, as shown in FIG. 14, the hinge bases 78, 78' located at the parting line during blow molding are formed at a position farther from the mating surface 76 of the container, and the width of the hinge 74 is increased. An attempt was made to resolve the above drawbacks.

However, the plastic container manufactured by blow molding as shown in Fig. 14 has the following (1), (2),
This would give rise to new problems such as (3).

(1) As shown in Fig. 15, as the mold consisting of one half mold 23 and the other half mold 24 is closed, the parison 21 inside the mold deforms along the mold cavity surface. I will do it. At that time, the compression part 26 for hinge molding of one half mold 23 of the cavity surface forming the vicinity of the hinge of the plastic container is
If the parison 21 is torn at the end 30 of A or the hinge side end 40 of the container mating surface molding part 27A of the other half mold 24, or the opposite end 3
0.40, there was a risk that the parison 21 would be torn due to shearing force, causing molding defects.

(2) Because the shear-compressed material is moved by the opposed ends 30 and 40 just before the mold closure is completed, the material is moved near the mating surfaces of the molded plastic container and around the hinge. This may cause appearance defects such as creases on the surface.

(3) When removing burrs formed on both ends of the hinge of a molded plastic container, if you move a blade such as a cutter along the parting line, the resistance between the burrs on the hinge ends and the burrs on the mating surface of the container will be extreme. As a result, the cutter could not be moved smoothly and there was a risk that cuts would occur, making it impossible to stably perform the burr removal work.

The present invention has excellent hinge characteristics and appearance characteristics, and also has excellent blow moldability, and burrs can be reliably removed.
The present invention provides a plastic container that is easy to use.

[Means for Solving the Problems] The present invention is made of a single plastic material, and includes a main body and a lid, and a compressed and thinned hinge that integrally connects the main body and the lid, and is made of a single plastic material. In a plastic container manufactured by blow molding that has a parting line 9 formed by sandwiching a plasticized parison around the entire circumference of the container, the parting line 9c formed on the hinge base is connected to the mating surface of the container. 2mm against
A parting line 9 formed in parallel and at a distance of 8 mm from the container and connecting the parting line 9a formed on the mating surface of the container with the parting line 9c formed on the hinge base.
Item b relates to a plastic container characterized in that it is expanded at an inclination angle α of 10 to 70 degrees with respect to the mating surfaces of the container.

[Function] In the present invention, in a blow-molded plastic container, the parting line 9c formed on the hinge base is set at 2 points with respect to the mating surface of the container.
Parting lines 9b are formed parallel to each other at a distance D of 8 mm from mm and connect the parting line 9a formed on the mating surface of the container and the parting line 9c formed on the hinge base. has a tapered beveled end of one mold half when closing the mold during blow molding by diffusing at an inclination angle α of 10 to 70 degrees with respect to the mating surface of the container. The protruding compression part and the recessed compression part of the other mold half, which has a tapered end that widens toward the end, evenly sandwich and compress the approximately middle part of the parison, so that the parison does not locally contact the inner surface of the mold. There is no risk of tearing due to contact, and by evenly pinching and compressing, the movement timing of the parison held between the inclined ends of the compression part and the movement timing of the parison held by the compression part other than the ends can be adjusted. are almost simultaneous, so the molded hinge,
Further, creases due to abnormal material movement of the parison do not occur near the container mating surfaces, and a plastic container with excellent moldability and excellent appearance characteristics can be obtained. Furthermore, when removing burrs from both ends of the hinge of a molded plastic container, the burrs are removed along the inclined parting line at the end of the hinge with the molded container closed. At this time, the distance between the parting line formed from the base end of the hinge on the container body side to the mating surface of the container and the parting line formed from the base end of the hinge on the lid side of the container to the mating surface of the container is Since there is no sudden change, the resistance applied to the cutter blade etc. during burr removal does not change drastically, allowing smooth burr removal work and leaving the hinge part beautiful.

[Example] Hereinafter, an example of the present invention will be described based on the drawings.

1 to 9 show a plastic container 1 manufactured by blow molding according to the invention, which plastic container 1 is made of a single plastic material, such as polyethylene, polypropylene, vinyl chloride, ethylene-acetic acid. It is made of a thermoplastic such as a vinyl copolymer or polyamide, and is composed of a main body 2, a lid 3, and a compressed thin hinge 4 that connects the main body 2 and the lid 3 together. The hinge 4 is compressed at a compression ratio of 2 to 40 times, preferably 5 to 30 times, and has a thickness of 0.2 to 1.0 mm.
It is preferably formed to have a wall thickness of 0.3 to 0.8 mm.
Note that the compression ratio is the ratio between the wall thickness of the parison before compression and the wall thickness after compression. The main body 2 and the lid 3 have inner walls 2A, 3A and outer walls 2B, 3B, respectively.
It has a double wall structure with 5, a storage section, 6 a mating surface of the container, and 7 a locking tool to which a separate item is attached.

Parting lines 9a, 9b, and 9c are formed by pressing plasticized parisons of plastic material, and are formed around the entire circumference of the container during blow molding. Further, these parting lines include a parting line 9a formed on the mating surface 6 of the container, a parting line 9c formed on the hinge base, and the above parting line 9.
It consists of a parting line 9b connecting a and 9c. Then, align the parting line 9c formed on the hinge base 2 with respect to the mating surface 6 of the container.
A parting line formed in parallel and apart from each other at an interval D of 8 mm from mm and connecting the parting line 9a formed on the mating surface 6 of the container and the parting line 9c formed on the hinge base. 9b is 10 degrees to 70 degrees with respect to the mating surface 6 of the container.
It is formed by diffusing at an inclination angle α of degrees. Note that parting lines 9a', 9b', and 9c' similar to the parting lines on the main body 2 side are also formed on the lid body 3 side.

10 and 11 show an apparatus for manufacturing a plastic container 1 manufactured by blow molding according to the present invention, where 10 is an extrusion head, and 11 is a cylindrical container made of plasticized thermoplastic such as polyethylene. Parison, 12 is half mold 13, half mold 14
It is a split type mold consisting of. One half mold 13
A convex cavity surface 15A forming the inner walls 2A and 3A of the main body 2 and the lid 3, and a compressed portion 16A forming the hinge 4 are formed in the main body 2 and the lid body 3, respectively. The other half mold 14 is formed with a concave cavity surface 15B forming the outer walls 2B and 3B of the main body 2 and the lid 3, and a compressed portion 16B forming the hinge 4. Note that 17 is a blowing nozzle. As shown in FIG. 11, the mating surface 6 of the container and the hinge 4 are formed on the parting lines 9a and 9c, which are the joining surfaces of the half molds 13 and 14, and the part connecting the hinge 4 and the mating surface 6 of the container is The parting line 9b is formed by widening at an inclination angle α of about 10 degrees to 70 degrees, and is formed by expanding the parting line 9b at the hinge 4 of the half mold 13.
The compressed part 16A forming the half mold 1 protrudes in a trapezoidal shape with a tapered inclined end.
The compressed portion 16B forming the hinge 4 of No. 4 is recessed so as to have an inclined end portion that widens toward the end.

Next, to explain the method for manufacturing the plastic container 1 according to the present invention, first, a thermoplastic plastic such as polyethylene is melt-kneaded in an extruder (not shown), and a plasticized cylindrical parison is produced from the extrusion head 10. Extruded as 11. parison 11
is placed between the opened mold 12, that is, the half molds 13 and 14, and then closes the set of molds 12 protruding into the convex cavity surface 15B of one half mold 13, and the parison 11 is sandwiched. . At this time, the parts connecting the blow molding 4 and the mating surface 6 of the container, that is, the parting lines 9b located at both ends of the compression parts 16A and 16B, are expanded at an inclination angle α, so that the mold 12 There is no fear that the parison 11 will be torn due to its closure.

That is, when the mold 12 is closed, a protruding compressed part 16A having a tapered end of one half mold 13 and a concave compressed part 16A having a tapered end of the other half mold 14 are formed. Since the compression section 16B evenly pinches and compresses the approximately middle portion of the parison 11,
There is no risk that the parison 11 will locally come into contact with the inner surface of the mold 12 and break. In addition, by evenly holding and compressing, the movement timing of the parison 11 (at the parting line 9b) held between the inclined ends of the compressed parts 16A and 16B and the compressed parts 16A and 16B other than the end parts can be adjusted. Since the timing of movement to the parison 11 (at the parting line 9c) held between the two is almost the same, the molded hinge 4 and the vicinity of the mating surface 6 of the container are bent due to abnormal material movement of the parison. Excellent moldability with no formation of meat.

Next, pressurized fluid such as compressed air is blown into the parting line 11 by the blowing nozzle 17, and the main body 2 and the lid 3 are formed by the convex cavity 15A and the concave cavity 15B.
By compressing approximately the middle of the parison 11 at 6A and 16B, a compressed thin hinge 4 is formed.
Next, after cooling the molded product formed from the parison 11, the mold 12 is opened to take out the molded product, and excess burrs are removed, thereby producing a plastic container 1 as shown in FIGS. 1 to 9. Ru. In addition, when removing the burrs formed on both ends of the hinge 4 of the molded plastic container 1, remove the burrs at the ends of the hinge 4 with the molded plastic container 1 open as shown in FIG. The burrs F are removed along the cutting lines 9c, 9c', 9b, 9b', 9a, and 9a'. At this time, the hinge base 8,
Since the distance between parting lines 9b and 9b' formed from parting line 8' to mating surface 6 of the container does not change suddenly, the resistance applied to the cutter blade etc. during burr removal does not change drastically and the process is smooth. burr removal work can be performed.

Note that in order to curve both ends 4' of the hinge 4 inward, a blade such as a cutter is cut along the parting lines 9b, 9b' formed at an angle with the container open. move diagonally to
It can be easily formed by removing burrs, and since the hinge base 8 is formed longer than the center, the bending strength of the hinge 4 can be significantly increased.

Since the present invention is constructed as described above, it is possible to obtain a container which has excellent hinge strength and has no gap between the mating surfaces of the container, and which has excellent protection properties for stored components. In addition, since the parting line connecting the hinge base and the mating surface is formed at an angle, the blow moldability is excellent and burrs can be removed reliably and easily, so that a container with excellent appearance characteristics can be obtained. Can be done.

Furthermore, since the hinge of the container is formed at the compressed part where the parting lines at both ends are inclined, when removing burrs with the container closed after molding, it is extremely easy to remove burrs along the inclined parting lines. can do.

The plastic container of the present invention may have a double-walled structure in which the outer, inner, and outer walls are joined to each other while the lid has a hollow double-walled structure. Furthermore, the plastic container of the present invention can be used for calculators, typewriters, measuring instruments, cameras, radios, binoculars, tanks, etc.
It can be used as a container for storing bolts, tools, etc., or as various housing members, and its uses are not limited in any way.

[Effects of the Invention] According to the present invention, it is possible to obtain a plastic container that has a beautiful hinge portion, has no creases, pockets of flesh, or cuts caused by removing burrs, and has excellent appearance characteristics.

[Brief explanation of the drawing]

1 to 9 show an embodiment of the plastic container according to the present invention. FIG. 1 is a partially cutaway side view of the plastic container, FIG. 2 is a rear view of the same, and FIG. 3 is a lid opened. Fig. 4 is a perspective view of the main part explaining the burr removal process with the lid closed, and Fig. 5 is a rear view of the main part showing an enlarged view of the vicinity of the hinge shown in Fig. 2. Figure 6 is B- of Figure 5.
B' sectional view, Figure 7 is a C-C' end view of Figure 5,
The figure shows an end view taken along the line D-D' of FIG. 5, FIG. 9 shows an end view taken along the line E-E' of FIG. 5, and FIGS. 10 and 11 show the manufacturing process of the plastic container according to the present invention.
Fig. 10 is a vertical cross-sectional view of the mold approximately at the center, Fig. 11 is a cross-sectional view taken along line A-A' in Fig. 10, and Figs. 12 to 14 are side views of the hinge portion for explaining the problems of the present invention. FIG. 15 is a cross-sectional view of a mold near the compression section immediately before the mold is closed, illustrating a conventional manufacturing method for manufacturing a container as shown in FIG. 14. 1...Plastic container, 2...Main body, 3...
Lid body, 4... Hinge, 6... Container mating surface, 9
a, 9b, 9c...Parting line.

Claims (1)

[Claims] 1 Constructed from a single plastic material, consisting of a main body, a lid, and a compressed thin hinge that integrally connects the main body and lid, and formed by sandwiching a plasticized parison of the plastic material. In a plastic container manufactured by blow molding that has a parting line 9 around the entire circumference of the container, the parting line 9c formed on the hinge base is 2 mm to 8 mm from the mating surface of the container.
Parting lines 9b are formed parallel to each other at distances D from each other and connect parting lines 9a formed on the mating surfaces of the containers and parting lines 9c formed on the hinge base. An angle of inclination α of 10 degrees to 70 degrees with respect to the mating surface of
A plastic container characterized by being formed by expanding.