JP2004244060A - Partially transparent blow-molded container and method for manufacturing the same - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a container with a transparent part on a specified position by blow molding. <P>SOLUTION: A plastic container with a specified transparency is provided by partially thinning down the specified position of the container. A parison is blown up by blow molding and a part of the parison is thinned down before the parison is solidified. <P>COPYRIGHT: (C)2004,JPO&NCIPI

Description

[0001]
TECHNICAL FIELD OF THE INVENTION
TECHNICAL FIELD The present invention relates to a plastic hollow molded body having a partially transparent portion, and more particularly to a plastic container for storing and supplying a liquid or a powder, for storing a liquid or a powder stored in the container. It can be used for containers that need to check the amount and residual amount. Specifically, it can be used for an oil tank used for OA equipment, a toner bottle, a liquid container used for industry, an oil tank used for an automobile, a reserve tank, and the like.
[0002]
[Prior art]
Conventionally, a hollow container manufactured by blow molding or the like is used to store and supply liquid or powder, and to make the container transparent for the purpose of detecting the amount of liquid or powder stored or remaining inside the container. To do so, a method of using a resin having high transparency (for example, polycarbonate / polyethylene terephthalate) or adding a clarifying agent to a translucent resin (for example, polypropylene / polyethylene) to impart transparency is employed. Was.
[0003]
When a transparent detecting portion is provided inside the hollow container, a transparent detecting portion formed separately is formed in the hollow container formed by blow molding, and the transparent detecting portion is thermally attached to the hollow container. For example, such a method is employed that the amount of liquid or powder stored in the opaque container can be detected.
[0004]
[Problems to be solved by the invention]
According to the above-described conventional method, containers having transparency necessary for detecting the amount of liquid or powder contained in the hollow container are made by various methods. When a hollow container is made using a resin, generally a highly transparent resin (for example, polycarbonate / polyethylene terephthalate) is not only expensive, but also difficult to blow-mold, is inferior in productivity, and the obtained product is expensive. It became something.
[0005]
The desired transparency can be obtained by using a crystalline translucent resin (for example, polypropylene or polyethylene) and making it extremely thin. However, in a method such as blow molding, only a desired position necessary for detecting the contents is obtained. It is difficult to reduce the thickness, and if the whole is reduced in thickness, the strength of the container is reduced. If the strength of the container is to be maintained, the thickness must be increased, resulting in a loss of transparency. Therefore, a method of adding a clarifying agent to the translucent resin to suppress crystallization of the crystalline resin and impart transparency is taken, but the clarifying agent to be added is expensive, and as a result, Cost increased.
[0006]
Furthermore, the method of retrofitting a transparent separate part to a hollow body container involves forming the transparent part in advance and then welding it to a blow-molded hollow body, which requires not only man-hours but also costs. There were drawbacks such as becoming high.
[0007]
An object of the present invention is to solve the above-mentioned conventional drawbacks and to form a portion having a desired transparency at a desired portion of a hollow body container formed by blow molding, so that the contents can be detected inexpensively and efficiently. An object of the present invention is to provide a hollow container having a structure.
[0008]
[Means for Solving the Problems]
In the present invention, when a hollow body is formed by blow molding, a movable thin mold portion provided in a blow mold is formed with a thin portion having transparency, and then the thinned transparent formation is performed. The part is moved to the desired part and position in the blow molding die forming the container by moving the split mold, and finally cooled and solidified, and the part is transparent and the contents can be detected. This is to obtain a blow molded hollow body having a structure.
[0009]
The formation of the hollow container having a thin transparent portion by the blow molding of the present invention is performed as follows.
[0010]
A movable mold part is provided in a part of the blow molding mold that is to be made thinner and transparent to form a hollow body container, and at the time of blow molding, the mold part to be made transparent is first formed into a container body. The parison (cylindrical molten resin) required for blow molding is then supplied and clamped, and the parison contained in the mold is pressurized with pressurized gas. Blow up. The blow-up parison first contacts the general container body forming part to form a part having a predetermined thickness, and then the parison further blown up by the split mold part located outside the container body part is thinned. Make the part that was done. After the parison has completely blown up, at the time of the resin in a semi-molten state before the parison is completely solidified, the split mold portion having the thinned resin portion is brought close to the mold surface of the container body forming portion. Or it is moved to the inner position, held at a predetermined position, and while holding the split mold at the predetermined position, the resin housed in the mold is cooled and solidified by blow molding to obtain a desired hollow body. Get the container.
[0011]
The formation of the transparentized portion according to the present invention is a method utilizing thinning by blow molding, and a desired transparentizing required portion is formed by a movable split mold portion located at an outer position provided in a blow molding die. Then, by moving the split mold portion, a thin transparent portion is formed at a desired portion / position of the hollow container, so that a blow molded body having a desired transparency can be obtained only by a mechanism using a mold. Therefore, any resin can be used as long as transparency can be obtained by thinning, and not only can molding be performed by a general molding machine, but also a hollow body having a transparent portion can be easily obtained in one step. If necessary, there is an advantage that a transparent portion protruding inside the container can be formed, and a hollow container having a transparent portion can be provided inexpensively and efficiently.
[0012]
BEST MODE FOR CARRYING OUT THE INVENTION
Hereinafter, the present invention will be described in detail with reference to the drawings.
[0013]
1 (a) to 1 (c) are schematic sectional views of a first embodiment of the present invention, showing a means for forming a portion to be made transparent, showing the operation of a blow molding die.
[0014]
FIG. 1A is a schematic cross-sectional view showing a state in which a parison blow-up is performed by externally providing a thin-wall forming part split mold that is transparent from a mold wall surface forming a hollow molded body main body.
[0015]
FIG. 1B is a schematic cross-sectional view showing a state in which the split mold of the thin transparent portion formed in FIG. 1A is moving.
[0016]
FIG. 1C is a schematic cross-sectional view showing a state in which the split mold of the thin transparent portion formed in FIG. 1A is finally inserted into the hollow body from the adjacent wall.
[0017]
FIG. 1A is a schematic cross-sectional view showing a state in which a parison is blown up with a thin-wall forming part splitting mold that is to be transparent positioned outside a mold wall surface forming a hollow molded body main body. A mold 1 for forming a body is composed of a mold surface 1a for forming a wall surface of a general container main body and a mold splitting portion 1b for forming thin and transparent, and a movable thin-walled portion is formed on the mold splitting portion 1b. A top 2 is provided, and the top 2 has a structure that can be moved by a mold splitting portion 1 b by a slide mechanism 3 provided on the mold 1. The contact wall 1c between the top 2 and the mold splitting part 1b of the mold splitting part 1b in which the movable thin-walled forming piece 2 is housed has a parison (resin) blown by gas but blown up. It has a clearance that does not pass through and allows gas in the mold of the thin-wall forming section extruded by blow-up to escape during blow-up of the parison during blow-molding. When moving to the mold surface 1a side, it has a clearance through which the thin-walled resin in a semi-molten state can be extruded without leaving the mold splitting portion 1b.
[0018]
First, as shown in FIG. 1A, a mold 1 for forming a hollow body container is positioned at a position where a thin-walled section piece 2 is provided outside a container mold surface 1a adjacent to the thin-walled forming piece 2 in a mold splitting portion 1b. To keep. Next, the parison (cylindrical molten resin) supplied from the extrusion mechanism (not shown) of the blow molding machine is housed in the mold 1, and after clamping, the parison is compressed by the pressurized gas supplied from the inside of the parison. Blow up. The blown-up parison 5 forms a thick resin layer 5a on the wall surface 1a of the general container body in the mold, but the parison is formed on the wall surface 1a of the thin wall located outside the wall surface 1a of the general container. The thinner resin layer 5b is formed by stretching. The thickness of the thinned resin layer 5b can be controlled by changing the position of the thin-wall forming piece 2 in the mold 1 shown in FIG. 1 (a). It becomes thicker if the outer position is closer. Therefore, the position of the thin-walled top 2 is adjusted according to the type of resin to be molded and the thickness of the parison to be supplied.
[0019]
Immediately after the blow-up of the parison shown in FIG. 1A is completed and the resin layer 5b is formed on the thin-wall forming section piece 2, the resin layer 5 formed by the blow-up parison is not completely solidified and is not solidified. In the molten state, as shown in FIG. 1 (b), the thin-walled forming piece 2 provided on the split mold part 1b is gradually moved to the general container body wall surface 1a side, and the thin-walled piece shown in FIG. It moves to the forward end of the formation top 2.
[0020]
This movement of the thin-walled forming top 2 gradually moves the top 2, and a thin-walled resin in a semi-molten state is formed on the contact wall surface 1 c between the top 2 and the die forming section 1 b of the die forming section 1 b. Move so as not to remain in the mold part 1b. The top 2 is moved by the slide mechanism 3 with a force higher than the pressing force applied inside the blow molding parison.
[0021]
FIG. 1C is a schematic cross-sectional view showing a state in which the thin-wall forming piece 2 has moved to the forward end. In this embodiment, the thin-wall forming piece 2 is located inside the general container body wall surface 1a. Through the steps shown in FIGS. 1A and 1B, while maintaining the state shown in FIG. 1C, molding, cooling, and solidification of the blow molding are performed, and finally, a molded product is taken out of the mold to obtain a desired product. A molded article having a transparent thin portion is obtained.
[0022]
2 (a) to 2 (d) are a schematic external view of a molded product obtained by the method of Example 1, a schematic partial cross-sectional view of the product, and a schematic cross-sectional view according to a conventional method.
[0023]
FIG. 2A is a schematic view of a partial appearance of a molded product obtained by the method of Example 1. The molded product 6 has a thin transparent portion 6b provided on a general main body 6a. The transparent thinned portion 6b is provided with a wall surface inside the general main body 6a, and a sensor (not shown) and the like are provided in a concave portion 6c formed by the general main body 6a and the transparent thinned portion 6b as necessary. It has a structure that can be installed.
[0024]
FIG. 2B is a partial cross-sectional view showing a cross section AA of the molded product 6 in FIG. The general main body 6a has a sufficient thickness to maintain the strength of the container, and the transparent thinned portion 6b has a sufficient transparency to detect the amount of liquid or powder stored and supplied in the container. Has the property. Further, a space in which a detection mechanism such as a sensor can be incorporated can be formed in the concave portion 6c formed by the transparent thinned portion 6b provided inside the container 6.
[0025]
FIG. 2C shows an example in which the thin transparent portion 6b 'formed by the method of the first embodiment is flush with the wall surface of the general main body 6a'. In the case of forming the shape of FIG. 2C, in the stage of FIG. 1C of the first embodiment, the thin-walled forming piece 2 is moved, and the thin transparent surface finally formed is the same as the general container wall surface 1a. It can be created by positioning it to be a plane.
[0026]
FIG. 2D is a cross-sectional example of the wall surface of the container in a case where the present embodiment is not used. Since a mechanism for reducing the thickness is not provided, the thin-walled transparent structure shown in FIGS. 2B and 2C of the present embodiment is used. The wall surface 6b "corresponding to the portions 6b, 6b 'becomes thicker than the general wall surface 6a", and transparency due to thinning cannot be obtained.
[0027]
In general, the blow molding does not provide sufficient transparency and the molding by the method of Example 1 shown in FIGS. 2 (b) and 2 (c) is a crystalline resin which requires an additive such as a clarifying agent. In the case of application using polypropylene, the general body portions 6a and 6a 'of the container need to have a thickness of 2 to 3 mm. In this case, the container body is translucent and turbid, and the inside of the container is like water. When it was filled with a colorless transparent liquid, it was difficult to visually confirm the filling of the liquid inside from the outside. However, the portion where the thin-walled portions 6b and 6b 'were formed to be about 0.5 mm was used. The colorless and transparent liquid filled inside was easily recognized visually. Since the wall 6b ″ shown in FIG. 2D to which the embodiment according to the present invention is not applied is thick, it is difficult to visually confirm the filling of the internal liquid from outside.
[0028]
FIGS. 3A and 3B are schematic views and cross-sectional views of another example showing an embodiment according to the present invention, in which the shape and position of a thinned transparent portion are different.
[0029]
FIG. 3A shows an example in which a thin transparent portion having a rectangular shape is provided. A transparent portion 8 is provided in the longitudinal direction of the side surface of the storage container 7 so that the residual level of the liquid or powder stored in the container is reduced. It has a structure that can be confirmed at any position.
[0030]
When the storage container 7 shown in FIG. 3A is blow-molded with a polypropylene resin, the general thick part is 2-3 mm, and the transparent part 8 is about 0.5 mm, the general part is opaque and filled inside. Although it was difficult to visually recognize the colorless and transparent liquid from the outside, the filling level of the colorless and transparent liquid filled in the transparent portion could be easily determined visually.
[0031]
FIGS. 3B and 3C show an example in which a cylindrical transparent portion 10 protruding inside the container 9 is provided, and the remaining amount of the liquid or powder stored in the container reaches the bottom of the container. It has a structure that sometimes detects the presence or absence of contents. In the case of this structure, a detection mechanism such as a sensor can be attached to the cylindrical transparent portion to send a remaining amount warning signal.
[0032]
FIGS. 4A and 4B are schematic diagrams of a conventional configuration example corresponding to FIGS. 3B and 3C. This is an example in which a transparent detection portion 12 formed separately is attached to a container body 11 by heat welding.
[0033]
In the above examples according to the present invention, the thickness of the thin and transparent portion of the container capable of recognizing the colorless and transparent liquid filled in the container using the photoelectric sensor was different depending on the resin such as polypropylene or polyethylene. In general, it may be 1 mm or less, preferably 0.8 mm or less, and 0.5 mm has shown a good result for recognizing the filled liquid very easily. In this example, the effect was confirmed based on a colorless transparent liquid.However, if the liquid or the like to be filled therein is colored, it can be more easily recognized. Needless to say, a thick wall may be set.
[0034]
The present invention, as shown in the above embodiment, when forming a hollow body by blow molding, to form a transparent thin portion in the movable split mold portion provided in the blow molding die, Then, the thinned transparent forming part is moved to a desired part and position in the blow molding die forming the container by moving the split mold, and finally cooled and solidified, and partially cooled. It is intended to obtain a blow-molded hollow body having a transparent structure capable of detecting contents, and containers having transparent portions in various modes can be easily and inexpensively manufactured.
[0035]
Any resin can be used as long as it can be blow-molded and exhibits transparency when it is made thinner. For example, so-called general-purpose plastics such as polyethylene and polypropylene can be used. In addition, it is of course possible to use a resin which had to use a clarifying agent in the past.
[0036]
INDUSTRIAL APPLICABILITY The present invention makes it possible to make only necessary portions transparent while maintaining the strength of the entire container, and it is needless to say that the present invention can be used for various containers that need to detect the filling amount of the container contents.
[0037]
Further, the above-described embodiment is an example of an embodiment of the present invention, and it goes without saying that blow-molded articles having various aspects of the transparent portion in addition to the above-described embodiment are possible.
[0038]
【The invention's effect】
The effects provided by the present invention are as follows.
[0039]
In a hollow molded container that can be stored and supplied,
(1) A transparent portion capable of detecting the contents is easily provided at an arbitrary position of the container, and the container can be efficiently manufactured.
[0040]
(2) A container having a transparent portion where the contents can be detected is obtained in one step.
[0041]
(3) A container having a transparent functional portion can be provided without using an expensive transparent resin.
[Brief description of the drawings]
FIGS. 1A, 1B, and 1C are schematic partial cross-sectional views showing a procedure for forming a transparent portion according to a first embodiment.
2 (a) is a schematic diagram of a partial appearance of a molded article obtained by the procedure of the first embodiment, (b) and (c) are schematic diagrams of a partial cross section of the embodiment, and (d) is a schematic diagram of a partial cross section of a conventional method. .
FIGS. 3A, 3B, and 3C are a perspective view, a partial cross-sectional view, and a partial side view of another embodiment of the present invention.
FIG. 4 is a partial cross-sectional view and a partial side view showing a conventional configuration corresponding to (b) and (c) of the third embodiment.
[Explanation of symbols]
1 Mold 2 Top 3 Slide mechanism 5 Parison 6 Molded product

Claims (4)

A partially transparent blow molded container characterized in that a predetermined portion of a hollow body is thinned to have a predetermined transparency. 2. The blow-molded container according to claim 1, wherein the predetermined portion has transparency so that the presence or absence of the filling when the liquid or the powder is filled can be identified. 2. A blow-molded container according to claim 1, wherein said predetermined portion is on the same plane as an adjacent container portion or is provided inside the adjacent portion. In a method of manufacturing a blow molded container in which a predetermined portion of a blow molded container is thinned to have a predetermined transparency, a mold splitting mold portion of a thin and transparent portion is partially located outside other mold wall surfaces. The parison is blown in the state, and then the thin blow-molded wall is positioned closer to or inside the other mold wall by moving the mold split mold section before the parison is completely solidified. A method for producing a blow-molded container, comprising: holding the molding die portion at that position until the parison solidifies.

Images