JPS5841732B2 - Polyethylene terephthalate resin bottle - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a polyethylene terephthalate resin material, and more specifically, a polyethylene terephthalate resin material whose mechanical strength increases and transparency increases by biaxial stretching. The purpose is to obtain various advantages in terms of mechanical strength, appearance, and manufacturing by molding the mouth part, including the neck part, which is difficult to perform biaxial stretching molding, from other suitable materials.

Another purpose is to convey the material of the mouth member according to the purpose of use, thereby obtaining an increase in body size that is suitable for the purpose of use.

Furthermore, another object of the present invention is to provide a strong bonding force between the main body and the mouth member by appropriately setting the structure of the connecting piece integrally provided on the mouth member to achieve the connection between the mouth member and the main body. It is to gain weight.

Polyethylene terephthalate resin has extremely high transparency, a glossy surface, excellent gas buyer properties for oxygen and carbon dioxide gas, and does not contain additives such as plasticizers or stabilizers, so it is hygienic. There are no problems and it is highly safe.
It has many excellent properties such as excellent content resistance and aroma retention, no toxic gas is generated when burned, and low combustion heat, but on the other hand, it has extremely low viscosity in the molten state. The molding method is because it has properties such as becoming cloudy when slowly cooled around 140 (0), does not exhibit sufficient mechanical strength unless biaxially stretched, and deteriorates in transparency, and furthermore, turns white when exposed to alcohol, etc. was extremely limited.

The method for molding this polyethylene terephthalate resin is limited to the in-die ex-shop blow molding method, that is, a method in which a piece, which is a primary molded product, is molded by injection molding, and then this piece is blow molded.

By the way, biaxial stretching molding, which provides polyethylene terephthalate resin molded products with sufficient mechanical strength, high transparency, and stable physical properties, is performed during blow molding operations; When molding the body, the mouth of the augmented body, including the neck, will not be stretch-molded at all.

This is exactly the same even if the molding material of the extension to be blow molded is polyethylene terephthalate resin, and therefore, the extension made of polyethylene terephthalate resin that is finally biaxially stretched by blow molding is While the body has sufficient mechanical strength, high transparency, and chemically stable physical properties, the mouth, including the neck, which is not or hardly stretch-molded, has poor mechanical strength. This is not necessarily sufficient, and it has the serious drawback that it is inferior in transparency compared to the body, and furthermore, it cannot be said to have chemically stable physical properties.

The present invention has been devised to eliminate the drawbacks of the above-mentioned biaxially stretched polyethylene terephthalate resin, and to fully exhibit the various excellent properties of polyethylene terephthalate resin. The mouth part including the neck part of the body is molded from a suitable material other than polyethylene terephthalate resin, and the main body part, which undergoes sufficient biaxial stretching, is molded from polyethylene terephthalate resin.

Embodiments of the present invention will be described below with reference to the drawings.

The body 1 according to the present invention includes a main body 2 forming a body formed of polyethylene terephthalate resin and biaxially stretched, and a material other than polyethylene terephthalate resin that is tightly fixed to the opening edge of the main body 1. Mouth member 3 forming the mouth including the neck of the molded body extension 1
It is composed of.

The mouth member 3 has a configuration in which a connecting piece 3b is hung down from the lower end surface of a cylindrical base body 3a having a short cylindrical shape.The mouth member 3 is closely fixed to the main body 2. This is achieved by bringing the lower end surface into close contact with the opening edge surface of the main body 2 and by embedding the connecting piece 3b in the opening edge portion of the main body 2.

By the way, while the main body 2 is molded from polyethylene terephthalate resin, the mouth member 3 is molded from a suitable material other than polyethylene terephthalate resin. The adhesion between the mouth member 2 and the mouth member 3 may be poor.

Therefore, the close fixation between the main body 2 and the mouth member 3 is achieved mainly by embedding the coupling piece 3b integrally within the main body 2.

As is clear from this, in the enlargement 1 of the present invention, how to integrally fix the mouth member 3 to the main body 2 is extremely important.

A method of molding the extension 1 that achieves strong and reliable fixation of the mouth member 3 to the main body 2 will now be described.

(See Figures 2 to 4 below) When injection molding the piece 2' which is the primary molded product of the main body 2, the mold cavity 9 is formed by the injection mold 4 for molding the piece 2' and the core 6. The mouth member 3 is assembled to the injection mold 4 and the core 6 so that the lower end surface of the mouth member 3 forms a part of the mold surface of the piece 2' with the connecting piece 3b protruding therein.

The mouth member 3 is assembled into the mold cavity 9 so that it is positioned opposite to the eye end of the mold cavity 9, which has a substantially straight cylindrical shape with a bottom.

That is, as shown in FIG. 2, the opening member 3 is attached to the core 6 assembled to the block 8 via the core base 7.
By fitting and assembling the injection mold 4 into the core 6 until it abuts against the core base T, and forming the mold cavity 9 by assembling the injection mold 4 to the core 6 with the mouth member 3 being fitted and assembled to the base end of the core 6. The mouth member 3 has the connecting piece 3b protruding into the mold cavity 9, and its lower end surface is positioned as part of the mold surface.

From this state, molten polyethylene terephthalate resin is injected into the mold cavity 9 through the runner 5 formed in the injection mold 4 to injection mold the piece 2'.

That is, since the piece 2' is injection molded with the lower end surface of the mouth member 3 on which the connecting piece 3b is suspended as part of the mold surface, the opening upper edge of the piece 2' is formed on the lower end surface of the mouth member 3. At the same time, the connecting piece 3b is embedded in the opening edge of the piece 2'.

Once the piece 2' has been molded using the mouth member 3 as part of the mold, the piece 2' and the mouth member 3 are taken out of the injection mold apparatus, and the stretching pin 10 is inserted into the piece. The piece 2' and the mouth member 3 are assembled into one body with the mouth member 3 fitted into the pin base 11 with the piece 2' inserted into the pin base 11, and then the mouth member 3 is inserted into the blow mold. 12
Fix the mold by clamping it.

That is, of the piece 2' and the mouth member 3 that are integrated, the mouth member 3 is held immovably between the pin base 11 and the blow mold 12, and the piece 2' is formed by the blow mold 12. It will be located within the molding space.

From this state (see Fig. 4), the stretching pin 10 is operated to uniaxially stretch only the piece 2' portion, or the stretching pin 1
At the same time as the uniaxial stretching operation of 0, pressurized fluid is injected into the piece 2' through the passage formed in the stretching pin 10, and the piece 2 is
' is biaxially stretched blow molded.

At this time, the part fixed to the blow mold device is the mouth member 3.
Therefore, almost the entire piece 2' made of polyethylene terephthalate resin will be biaxially stretched.
The main body 2 formed by biaxial stretching has high mechanical strength, high transparency, and exhibits chemically stable physical properties.

In this way, the above-described method for molding the extension 1 uses the mouth member 3 as a part of the mold for the piece 2', which is the primary molded product of the main body 2, so that the main body 2 and the mouth member 3 are This means that the integral assembly of the pieces 2' can be achieved in a completely tight and strong manner when molding the piece 2'.

Also, during biaxial stretching molding of piece 2', toss 2'
Since the fixing of the piece 2' to the mold device can be carried out via the mouth member 3, the means of fixing the piece 2' to the mold device can be achieved easily and strongly.
Portions can be made extremely small.

By the way, since the mouth part member 3 is molded completely separately from the main body 2, the function as the mouth part of the extension part 1 can be performed using a synthetic resin material other than polyethylene terephthalate resin, which does not require biaxial stretching molding. It is molded from a synthetic resin material that has physical properties appropriate for the purpose, such as a material with excellent mechanical strength, a material with a beautiful appearance, and a material with desired physical properties such as a material with high compatibility with polyethylene terephthalate resin. It can also be molded from metal to obtain higher mechanical strength of the mouth and to improve its appearance.

That is, the molding material for the mouth member 3 is not limited at all, and the most suitable material may be selected depending on various conditions such as the usage environment of the filler 1, the type of contents, the sealing structure, and the manner of use. All you have to do is use them selectively.

In addition, since the mouth member 3 can be molded completely separately from the main body 2, polyethylene terephthalate, which can be opened and closed by a screw cap, is made by making the thread 3c moisture-resistant, which would cause various difficulties when molded into the main body 2. It is possible to easily obtain the resin-made extension 1.

Now, as described above, the close fixation of the main body 2 and the mouth member 3 is achieved by the close contact between the main body 2 and the mouth member 3 at their contact surfaces and by embedding the connecting piece 3b in the main body 2. However, if the mouth member 3 is molded from a synthetic resin material that is highly compatible with polyethylene terephthalate resin, there will be no particular problem in closely fixing the main body 2 and the mouth member 3. However, if the mouth member 3 is made of a material such as metal that is not compatible with polyethylene terephthalate resin, the joint piece 3b may be used to secure the body 2 and the mouth member 3 in close contact with each other. You will be the main player in achieving and maintaining your goals.

Therefore, in such a case, the structure of the connecting piece 3b needs to be not only embedded in the main body 2, but also firmly engaged with the main body 2 in a manner that cannot be displaced.

FIGS. 5 and 6 show examples of the structure of the coupling piece 3b suitable for maintaining the mouth member 3 tightly fixed to the main body 2 by the coupling piece 3b.

The structural example of the connecting piece 3b shown in FIG.
This is an example in which the lower end of the connecting piece 3b is enlarged in the vertical direction toward the outside of the plate than the middle part (center part).With this configuration, the connecting piece 3b cannot be removed from the inside of the main body 2.

Note that the huge portion at the lower end of this joint piece 3b is
As shown in the figure, by raising the outer portion of the upper surface to form a key shape, it is possible to more completely prevent the piece 2' and the mouth member 3 from coming off during the stretching operation of the piece 2'.

The structural example of the connecting piece 3b shown in FIG.
A through hole is formed in a part of the piece 2', and this example is effective when the wall thickness of the piece 2' is not sufficient.

Of course, the structure of the connecting piece 3b is not limited to the above two examples, and may be a combination of the above two examples or another structure.

In short, it is sufficient that the mouth member 3 is strongly assembled and held on the main body 2 by the connecting piece 3b.

Also, the connecting piece 3b? Although it is obvious in view of the required operational action, the positional relationship of the two connecting pieces 3b with respect to the main body 2 is not necessarily limited to one in which the entire connecting piece 3b is completely buried within the main body 2. Rather, even if a part of the connecting piece 3b is exposed outside the main body 2, the part of the connecting piece 3b located inside the main body 2 ensures a strong assembly between the main body 2 and the mouth member 3. may be something that can be maintained.

As is clear from the above description, the present invention eliminates all the disadvantages in the mouth area including the neck area that cause various inconveniences in terms of structure, appearance, and physical properties in biaxially stretched polyethylene terephthalate resin extensions. In addition, there is no need for a holding mechanism to fix the piece 2' to the blow mold device, simplifying the structure of the mold. The required mouth part can be molded with a material that is compatible with the required operation mode, and the threaded part of the mouth part, which is extremely difficult to mold with biaxial stretching, can be formed independently of biaxial stretching. It has many beneficial effects as a polyethylene terephthalate resin extension having excellent properties such as easy molding.

[Brief explanation of the drawing]

FIG. 1 is a longitudinal cross-sectional view showing the structure of a bulking device according to the present invention. Figures 2 to 4 are longitudinal sectional views showing the order of molding the addition shown in Figure 1, and Figure 2 shows the state in which the mouth member is assembled into the injection molding machine for the piece, which is the primary molded product. , Figure 3 shows the injection molding of the piece, and Figure 4 shows the injection molding of the piece into the main body.
Each figure shows the axial stretch blow molding operation. Figures 5 and 6 show examples of the structure of the connecting pieces,
FIG. 5 is a longitudinal sectional view of the connecting piece with its lower end enlarged, FIG. 6a is a front view of the connecting piece provided with a through hole, and FIG. 6 is a longitudinal sectional view thereof. Explanation of symbols, 1; Increase, 2: Main body, 2'; Piece, 3;
Mouth member, 3a; cylindrical base, 3b; connecting piece, 3c; screw, 4; injection mold, 5; runner, 6; core, 7; core base, 8: mounting block, 9; mold cavity; 10: Stretch pin, 11: Pin base, 12: Blow mold.

Claims (1)

[Scope of Claims] 1. A cylindrical base body 3a having a cylindrical shape is attached to an open end edge of a main body 2 which is molded mainly from polyethylene terephthalate resin, and which is biaxially stretch-produced from polyethylene terephthalate resin. A mouth member 3 made of an appropriate material has a connecting piece 3b of a desired shape hanging down from the lower end surface of the mouth member 3,
By injection molding the bottomed cylindrical primary molded product of the main body 2 with the lower end surface of the mouth member 3 and the coupling member 3b as part of the mold surface, the lower end surface of the mouth member 3 is An extension made of polyethylene terephthalate resin that is closely attached to the opening edge of the main body 2 and is integrally assembled with the coupling member 3b embedded within the opening edge of the main body 2. 2. The extension as set forth in claim 1, in which a thread 3c is formed on the outer peripheral surface of the cylindrical base body 3a of the mouth member 3. 3. The enlargement according to claim 1, in which the mouth member 3 is molded from a synthetic resin material other than polyethylene terephthalate resin. 4. The enlargement according to claim 1, in which the mouth member 3 is molded from metal. 5. The extension as set forth in claim 1, in which the connecting piece 3b of the mouth member 3 has a structure in which the lower end is enlarged. 6. The extension according to claim 1, wherein the connecting piece 3b of the mouth member 3 has a structure having a through hole of a desired diameter.