JPS6135056B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a container made of polyethylene terephthalate resin produced by biaxial stretch blow molding.
In particular, the main purpose is to obtain a container whose mouth part is not biaxially stretched but whose body part is biaxially stretched, and whose mouth part which is not biaxially stretched is stable both physically and rigidly. It is something to do.

Polyethylene terephthalate resin has excellent physical properties such as gas barrier properties and transparency, and is therefore attracting attention for its aesthetic advantages and is used as a material for containers such as bottles.

The polyethylene terephthalate resin container is usually formed by biaxially stretching and blowing a bottomed cylindrical piece that is a primary molded product, but the parts of the container of the present invention that are not biaxially stretched, such as the mouth, are made of resin. Its physical properties are unstable, and it is susceptible to the effects of heat, etc., making it easily deformed. However, containers such as bottles often require strict sealing depending on the contents, and in particular, the mouth part is sealed with the top surface of the mouth part, caulked with a crown, or sealed with a seal etc. It will be sealed in a cap. Therefore, if the mouth portion is deformed due to external factors such as heat, there is a risk that the sealing effect will be diminished.

The present invention has an unstretched opening and an unstretched annular supporting ridge at the lower end of the opening, and the opening is whitened and crystallized to provide excellent stability in terms of physical properties. Even if the contents are filled by hot filling, the mouth part will not shrink and deform, and the sealing performance with the cap that seals the mouth part can be maintained to prevent the contents from leaking from the mouth part. Because the annular support rim is whitened and crystallized, the annular support rim will remain intact even when the pressure when fitting the cap into the mouth and the heat of the contents act on the annular support rim. provides a polyethylene terephthalate resin container that does not deform at all.

The structure of the polyethylene terephthalate resin container of the present invention will be explained below based on the embodiment shown in the drawings.

As shown in FIGS. 1 and 2, in the main body 10 of the polyethylene terephthalate resin container, the body 12 is biaxially stretch blow-molded from an intermediate material that is a primary molded product (not shown), and the mouth 11 is a portion in which the mouth shape formed at the time of forming the intermediate material is maintained as it is, that is, the portion is not biaxially stretched.

An annular support ridge 13 is formed at the lower end of the mouth 11, and the container body 10 is biaxially stretched by holding the annular support ridge 13. This annular supporting flange 13 also serves as a supporting part for biaxial stretching as described above, but in the present invention, it serves as a part that fixes and supports the container when fitting the cap into the mouth after forming the container. It is. This annular supporting flange acts to directly receive the pressure required for fitting the cap. The mouth portion 11 including the annular support ridge portion 13 is whitened and crystallized by appropriate means, so that the mouth portion 11 and the annular support edge portion 13 that are not biaxially stretched are improved both physically and rigidly. Excellent stability can be obtained, and deformation due to heat or the like is unlikely to occur.

As mentioned above, by whitening and crystallizing the mouth part, even if the contents are heat-filled, it is possible to sterilize the inner surface of the container and the cap after the cap is fitted. Even if heat of the contents itself or heat of other heating means is applied, shrinkage and deformation due to the heat of the mouth part will not occur at all. As a result, the seal between the mouth and the cap is completely maintained, and there is no leakage of the contents from the mouth.

Furthermore, as mentioned above, by whitening and crystallizing the annular support rim that serves as a fixed support for the container body when the cap is fitted, stress deformation due to the pressure for cap fitting, that is, the upper part of the periphery of the annular support rim It is possible to prevent warpage and deformation of the cap, and also to prevent the distal end of the cap from coming into contact with the deformed portion, making it impossible to fully fit the cap. In other words, by whitening the annular support ridge, in the case of hot-filled contents, shrinkage deformation in the radial direction due to the heat temperature of the contents and stress deformation in the axial direction due to pressure due to cap fitting are suppressed. It can be prevented.

Further, since the mouth portion 11 and the annular support ridge portion 13 are not biaxially stretched as described above, they are easily subjected to whitening and crystallization, and a thick mouth portion is obtained, resulting in excellent strength.

As described above, by forming the annular support ridge 13 at the lower end of the opening 11, the biaxial stretching process of the intermediate material can be easily carried out, and the whitened part of the opening and the transparent part of the body can be clearly separated. This creates a striking contrast as if a separate object were attached to the top of the main body, and gives a sense of cleanliness and beauty with good contrast in the decorative aspect as well.

After molding, the body 12 of the container body 10 is heat-treated by so-called heat setting at a temperature exceeding the softening point of polyethylene terephthalate resin in order to improve its heat resistance. At this time, the container body 10 is appropriately supported by a mold or the like so that it does not lose its shape due to heat. During the heat treatment of the body, the dimensional accuracy of the mouth 11 may be lost due to the heat, so the mouth 11 is whitened and crystallized before the heat treatment.

The present invention has the above-mentioned structure and operation, and by whitening and crystallizing the mouth part that is not biaxially stretched, the mouth part can be made extremely strong against heat, etc., and can be prevented from deformation, and has physical properties. Due to its excellent rigidity and stability, even if the contents are filled with heat, heat can be applied to sterilize the inner surface of the container and the inner surface of the cap after the cap is fitted. There is no shrinkage or deformation due to heat at the mouth, and as a result, the seal between the mouth and the cap is completely maintained, and there is no leakage of contents from the mouth. .

In addition, the mouth part is not stretched, and the shape of the mouth part formed at the time of the intermediate material is maintained as it is, so there is no need to consider the degree of stretching at all. The ability of the spout to maintain precise dimensional accuracy makes it possible to obtain a spout that is extremely effective in sealing the contents.

In addition, an annular supporting protrusion is formed at the lower end of the mouth,
It can be used as a support part for biaxial stretching and cap fitting, and by whitening and crystallizing the annular supporting ridge, shrinkage deformation in the radial direction due to heat can be prevented, and cap fitting Stress deformation in the axial direction, that is, upward warping due to the pressure generated during this process can be prevented, and the distal end of the cap may come into contact with the warped portion, causing problems such as insufficient fitting. This can be prevented. Furthermore, by providing a whitened crystallized annular support ridge at the lower end of the mouth, the whitened part of the mouth and the transparent part of the body are clearly separated, making it appear as if separate objects were attached to the upper part of the body. It shows a striking contrast, and in terms of decoration, it gives a good sense of cleanliness and beauty to the contrast.

Furthermore, since the opening and the annular support ridge of the container of the present invention are not biaxially stretched, whitening and crystallization can be applied extremely easily, and a thick opening can be obtained and the container has excellent strength. Furthermore, since the body is heat treated after molding, it has a high degree of heat resistance, which is a significant advantage for this type of container.

[Brief explanation of the drawing]

FIG. 1 is an overall view of the container according to the present invention, and FIG. 2 is a sectional view of the mouth. 10: Container main body, 11: Mouth, 13: Annular support flange.

Claims (1)

[Claims] 1. A container made of polyethylene terephthalate resin produced by biaxial stretch blow molding, including: a biaxially stretched container body, an unstretched opening, and an unstretched container formed at the lower end of the opening. The unstretched mouth portion and the annular support ridge are whitened and crystallized, and the body below the annular support ridge is heated to improve heat resistance after molding. A polyethylene terephthalate resin container characterized by being processed.