JP4051231B2 - Molding method for glass bottle-shaped small containers - Google Patents

Description

[0001]
BACKGROUND OF THE INVENTION
The present invention relates to a molding how the glass bottle shaped small containers by resin.
[0002]
[Problems to be solved by the invention]
The small containers targeted by the present invention are thick-walled bottles having a body diameter of 25 mm or less and a width of 25 mm or less and a small diameter, such as perfumes, pills and eye drops, most of which are made of glass. . Since glass has a mass, it is desired to reduce its weight even in a small container for portable use. Moreover, since the impact strength is weak, it is dropped and damaged during use, and the contents cannot be used, and are often wasted.
[0003]
For these reasons, small containers made of resin are required. In injection blow molding, which is used for molding bottles and containers, the inside of the mouth of the preform, which is the container mouth after molding, is injected. A preform formed around the outer side of the blow core is expanded by the pressure of the air blown from the front end of the injection blow core into a container such as a thin bottle.
[0004]
For this reason, since the injection blow core has both the core cooling water channel and the blow air circuit inside, there is a limit to the minimum outer diameter of the core, and the core cannot be designed to be smaller than that, and smaller than the minimum outer diameter. It is considered difficult to mold a small-sized container. In addition, the air blow from the injection blow core is in a state where the preform is being held in the core. Therefore, the thicker the wall thickness, the more difficult the uniform air blow and the uneven thickness are likely to occur. It has not yet been possible to mold a small container that exhibits a texture of a shape.
[0005]
The present invention has been conceived in order to solve the above-mentioned problems, and its purpose is to perform injection molding of a preform with a small-diameter injection core having only a core cooling water channel, and to form a small container by air blow, by separately performing the adoption is to provide a new molding how to make possible the shaping of small containers exhibiting glass bottle like texture in the side wall is thick.
[0006]
[Means for Solving the Problems]
In the molding method of the present invention according to the above object, the acrylic resin, polycarbonate resin, and polyester resin having gloss are injected and filled into the injection cavity around the injection core, the inner diameter of the mouth portion is small, and the height is substantially equal to the container height, A preform with a side wall thickness of 2 to 3 times the wall thickness of the container is molded, the preform is released and transferred to a cavity mold for container molding, and the bottom is compressed by inserting a fixed rod. Is fixed to the bottom of the cavity, the preform side wall is compressed and expanded to the cavity surface by air blow, and the side wall is transparently seen through light refraction and internal reflection, and combined with the surface reflection, the glass bottle-like texture It is formed into a small container exhibiting the following.
[0008]
DETAILED DESCRIPTION OF THE INVENTION
In the figure, 1 is a preform and 2 is a small container having a glass bottle-like texture formed by air blowing the preform.
[0009]
The preform 1 includes a block having a horizontally long quadrilateral shape in which a threaded mouth portion 11 serving as a mouth portion 21 of a small container 2 and four thick side walls 12 are integrally formed. A sprue 14 is formed to protrude. The side wall 12 of the preform 1 has a height of 20 mm, a thickness of 5.0 mm, a thickness of the bottom 13 of 2.0 mm, and an inner diameter of the mouth 11 of about 5.4 mm. Note that the sprue 14 is cut in some cases.
[0010]
The small container 2 is formed of a quadrilateral whose lateral section is a horizontally long quadrilateral with a mouth 21 having the same dimensions as the mouth 21 of the preform 1 and four side walls 22 and whose front is spread downward. The corner portion and the bottom corner portion are formed on the cut surface. The side wall 22 of the small container 2 has a height of 20 mm, a thickness of 2.5 mm, a thickness of the bottom 23 of 1.5 mm, and an inner diameter of the mouth 21 of about 5.4 mm.
[0011]
The preform 1 and the small container 2 can be formed by the steps shown in FIG. As the resin, an acrylic resin having a glassy texture, a polyester resin such as polyethylene terephthalate, and the like are preferable from the viewpoint of transparency, gloss and hardness, and an acrylic resin is particularly preferable.
[0012]
In the figure, 3 is an injection mold for the preform 1, 4 is a container mold, and 5 is an upper holding mold that also serves as a mold for the mouth portion 11, which is attached to the guide member 6 so as to be freely opened and closed, and is attached to the lower surface of the transfer member 7. It consists of a pair of split molds provided. 8 is an injection nozzle.
[0013]
The injection mold 1 includes an injection cavity mold 31, an injection core 33 (base outer diameter 5.4 mm) that is inserted into the injection cavity mold 31 through the upper holding mold 5, and an injection core thereof The injection cavity 8 is formed around the injection cavity 32, and the injection nozzle 8 touches the bottom surface of the injection cavity 32 through the pedestal 34. The preform 1 is formed by injecting and filling molten resin (for example, acrylic resin) into the injection cavity 32 from the injection nozzle 8.
[0014]
As shown in FIG. 4, the container molding die 4 has a cavity 42 that forms a container over the mold closed surfaces of a pair of split molds 41. The upper portion of the cavity 42 is formed by the lower surface of the holding die 5, and the blow core 44 is accommodated in the holding die 5 from above and is smaller in diameter than the preform inner diameter inserted into the central portion of the blow core 44 so as to be movable forward and backward. A fixed rod 43 having a blow passage 45 in the part is inserted from the mouth part 11 to the bottom part 13 of the preform 1. A bottom mold 46 is provided at the bottom of the cavity 42 so as to penetrate the machine base 9 and move up and down.
[0015]
In such a container molding die 4, in order to mold the preform 1 into a glass bottle-shaped small container 2, as shown in FIG. Also, a small-diameter fixed rod 43 is inserted. At the same time or thereafter, the bottom mold 46 is raised to compress the bottom 13 together with the sprue 14, and the bottom 13 is formed into the thin bottom 23 of the small container 2. Then, the preform 1 is fixed to the bottom of the cavity while keeping both in that position.
[0016]
After the preform 1 is fixed, compressed air of about 30 kgf is blown from the upper blow core 44 into the gap around the fixed rod 43. As a result, the wall portion 12 of the preform 1 is compressed and expanded to the cavity surface, and the small container 2 is formed. Further, the preform 1 is fixed at the top and bottom of the cavity by the mouth portion 11 and the bottom portion 13, and the air expands in the gap around the fixed rod and compresses and expands the side wall 12. Is applied evenly to the entire side wall, and uneven thickness which tends to occur on the thick side wall 12 is prevented.
[0017]
Further, air blow is performed to adjust the inner wall surface and the wall thickness distribution to ensure the internal capacity. As shown in FIG. 6, the preform 1 becomes a small-sized container 2 having a thick wall through which the side wall 22 is seen through by light refraction and internal reflection, as shown in FIG. 6. In this case, if there is a vertical difference in the gap between the preform 1 and the cavity surface due to the inclination of the cavity surface, the wall thickness of the lower side wall having a large gap tends to be formed thinner than the upper side wall. Since the side wall is seen through by refraction and internal reflection, the glass bottle-like impression is not lost.
[0018]
In the illustrated example, the bottom 13 is compressed and fixed by the fixed rod 43 and the bottom mold 46. However, depending on the cavity structure, the fixed portion 43 alone can be compressed and fixed.
[Brief description of the drawings]
1 is a diagram showing a half portion longitudinal front of the preform in the molding process of glass bottles shaped small type container according to the present invention (A) and the halves transverse plane (B).
2 is a diagram illustrating a semi-vertical sectional front glass bottle shaped small type container produced by the molding method according to the present invention (A) and the halves transverse plane (B).
FIG. 3 is a longitudinal sectional front view of an injection mold showing a preform molding state.
FIG. 4 is a longitudinal front view of a cavity mold for container molding showing a state where a blow core mold is inserted into a preform.
FIG. 5 is a longitudinal sectional front view of a cavity mold for container molding showing a state where a preform bottom is compressed and fixed.
FIG. 6 is a longitudinal front view of a cavity mold for forming a container, showing a molded state of a glass bottle-shaped small container.
[Explanation of symbols]
DESCRIPTION OF SYMBOLS 1 Preform 11 Mouth part 12 Side wall 13 Bottom part 14 Spru 2 Glass bottle-shaped small container 21 Mouth part 22 Side wall 23 Bottom part 3 Injection mold 31 Injection cavity mold 32 Injection cavity 33 Injection core 4 Container molding die 41 Cavity mold 42 Cavity 43 Fixation Rod 44 Blow core 46 Bottom type

Claims (1)

Glossy acrylic resin, polycarbonate resin, and polyester resin are injected and filled into the injection cavity around the injection core, the inside diameter of the mouth is small, the height is approximately equal to the container height, and the side wall thickness is the thickness of the container side wall. Form a 2 to 3 times preform,
After releasing the preform and transferring it to a cavity mold for container molding, after compressing the bottom by inserting a fixing rod and fixing the preform to the bottom of the cavity,
The preform side wall is compressed and expanded to the cavity surface by air blow, and the side wall is formed into a small container that is transparently seen through light refraction and internal reflection, and has a glass bottle-like texture combined with surface reflection. A method for forming a glass bottle-shaped small container.

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