JPH02258543A - Synthetic resin vessel - Google Patents

Abstract

PURPOSE:To make excellent in transparency and gas barrier ability of a body as well as excellent in heat resistance of an opening end especially of a mouth and a threaded part, and further of an undrawn part of a bottom by a method wherein at least 90wt.% of heat resistant resin based on an entire vessel is distributed at the mouth while at least 50wt.% of the heat resistant resin in the mouth is concentrated between the opening end and the threaded part. CONSTITUTION:The mouth of this polyester resin vessel comprises polyethylene terephthalate resin and heat resistant resin wherein at least 90wt.% of the heat resistant resin based on an entire vessel is distributed at a mouth and at least 50wt.% of the heat resistant resin in the mouth is concentrated between an opening end and a threaded part. The mouth comprises 40 to 75wt.% of polyethylene terephthalate resin and 25 to 60wt.% of heat resistant resin. If the amount of the heat resistant resin at the mouth is less than 90wt.% of the heat resistant resin based on the entire vessel, transparency and gas barrier ability of a body deteriorate. If the distribution of the heat resistant resin being distributed between the opening end and the threaded part is less than 50wt.% among the heat resistant resin distributed on the mouth, cap sealing ability of the mouth deteriorates.

Description

DETAILED DESCRIPTION OF THE INVENTION (Industrial Field of Application) The present invention relates to containers made of synthetic resin, and particularly to containers made of polyester resin.

(Prior Art) Generally, containers manufactured using polyester resin are sensitive to heat and easily deform when filled with hot liquid. In particular, the unstretched mouth and bottom of the container are susceptible to heat, and if thermal deformation occurs at the mouth, problems such as liquid leakage will occur, and heat deformation will also occur in the unstretched bottom. This is not preferable because the self-sustaining stability of the container decreases and the value as a container is lost.

As a countermeasure against the above-mentioned thermal deformation, it is possible to manufacture containers using heat-resistant resin, but in this case, it is also necessary to consider the suitability for the contents to be filled, and furthermore, this type of resin is generally expensive. Therefore, the manufacturing cost becomes high,
Lacks versatility.

Therefore, a container and a method for manufacturing the same have been proposed, which have a multi-layered structure mainly composed of a relatively inexpensive synthetic resin and a heat-resistant resin. For example, a method for manufacturing the container is known, as disclosed in Japanese Patent Application Laid-open No. 6355.

In this manufacturing method, first, when an appropriate amount of the synthetic resin is injected into a mold cavity for molding a container preform, the injection is temporarily interrupted, and when the injection is interrupted, a heat-resistant resin is injected and passes through the synthetic resin. Then, the synthetic resin is injected again to form a preform with a multilayer laminate structure in which the outer surface layer and the inner surface layer of the mouth part are made of heat-resistant resin, and then this preform is blow-molded. The aim is to manufacture a container with heat resistance, especially at the mouth.

However, in the above manufacturing method, depending on conditions such as the timing of injecting the heat-resistant resin, when heat-resistant resin such as polyallyl resin is used, the heat-resistant resin is not always concentrated in the unstretched part at the mouth and bottom. However, a large amount of heat-resistant resin is distributed even in the body of the container.

The heat-resistant resin distributed in the body in this way has the problem of reducing the transparency and gas barrier properties of the body, so it is preferable to manufacture containers that require transparency and gas barrier properties by the above manufacturing method. do not have. Furthermore, in order to reliably distribute a predetermined amount of heat-resistant resin in the mouth portion, a relatively large amount of heat-resistant resin must be used, which has been an obstacle to reducing manufacturing costs. Furthermore, the heat-resistant resin distributed in the mouth and bottom is more distributed toward the body side, and is distributed in the open end of the mouth and the threaded part, which are most important for heat resistance, and in the unstretched part of the bottom. If the amount is too low, the heat resistance of that part decreases and thermal deformation is likely to occur, resulting in a problem that the sealing performance of the cap at the mouth and the self-sustaining stability of the container decrease.

(Problems to be Solved by the Invention) The present invention eliminates such disadvantages and has excellent transparency and gas barrier properties of the body, as well as the opening end and threaded portion of the mouth, and the unstretched portion of the bottom. The purpose is to provide a synthetic resin container with excellent heat resistance.

(Means for Solving the Problems) In order to achieve the above object, the present invention provides a polyester resin container comprising a mouth, a body, and a bottom, and the mouth has a threaded part and a support ring. The mouth is made of polyethylene terephthalate resin and a heat-resistant resin, and 90% by weight or more of the heat-resistant resin in the entire container is distributed in the mouth, and 50% by weight of the heat-resistant resin in the mouth. The above features are concentrated between the opening end and the threaded portion.

Further, the mouth portion is made of 40-75% by weight of polyethylene terephthalate resin and 25-60% by weight of heat-resistant resin.

The mouth portion is formed from a heat-resistant resin and a polyethylene terephthalate resin having excellent gas barrier properties. When the amount of heat-resistant resin in the mouth becomes less than 90% of the total heat-resistant resin in the entire container, the heat-resistant resin in the body increases, which reduces the transparency and gas barrier properties of the core body. decreases. Of the heat-resistant resin distributed in the mouth, the amount distributed between the opening end of the mouth and the threaded portion is 50% by weight.
When the amount decreases, the heat resistance of the opening end and the threaded portion decreases, making the mouth portion more likely to be thermally deformed, and the sealing performance of the cap at the mouth portion decreases. Furthermore, if the amount of heat-resistant resin distributed in the mouth is less than 25% by weight of the total weight of the mouth, the heat resistance of the mouth may decrease; (
In this case, the amount of polyethylene terephthalate resin may decrease, resulting in a decrease in the gas barrier properties of the opening, and the manufacturing cost will also increase.

The present invention also provides a polyester resin container comprising a mouth, a body, and a bottom, and having an inwardly bowl-shaped unstretched part in the bottom, at least the open end of the unstretched part of the mouth. A heat-resistant resin is distributed in at least an unstretched part of the mouth part and the bottom part.The unstretched part of the mouth part and the bottom part is particularly vulnerable to heat, so if the heat-resistant resin is not distributed therein. , its heat resistance decreases and thermal deformation occurs, and if this occurs at the mouth, the cap sealing performance decreases, and if it occurs at the bottom, the self-sustaining stability of the container is impaired.

Furthermore, the heat-resistant resin is polyallyl resin, polyethylene 2.6 naphthalate, or polyethylene 1.5 naphthalate.

Among heat-resistant resins, these resins are particularly suitable for polyethylene terephthalate resin.

(Function) According to the present invention, according to the above means, 90% or more of the heat-resistant resin in the entire container is distributed in the mouth, and therefore the amount of heat-resistant resin distributed in the body is less than 10%. Since the amount is sufficiently small, the transparency and gas barrier properties of the body are ensured. In addition, more than 50% of the heat-resistant resin in the mouth is concentrated and distributed in the opening end and threaded part, so the opening end and threaded part are heat resistant, preventing thermal deformation and capping the opening. Sealing performance is ensured.

In addition, the mouth part is made of a structure made of heat-resistant resin and polyethylene terephthalate resin, and the amount of heat-resistant resin distributed in the mouth part is 25% or more of the total weight of the mouth part, so this improves the heat resistance of the mouth part. On the other hand, by setting it to 60% or less, gas barrier properties at the mouth are ensured.

Furthermore, in the present invention, by distributing the heat-resistant resin to the open end of the mouth and the unstretched part of the bottom, the heat resistance of the mouth and the unstretched part of the bottom is ensured, and the cap sealability of the mouth is improved. At the same time, the self-sustaining stability of the container is ensured by preventing thermal deformation of the bottom.

(Example) As a first example of the present invention, a container made of polyester resin in which heat-resistant resin is concentrated between the opening end of the container mouth and the screw part is shown in FIGS. 1 to 4. explain.

The polyester resin container of the first embodiment is made of polyethylene terephthalate resin 1 (hereinafter referred to as PE), as shown in FIG.
It is made by biaxial stretch blow molding using T resin 1) and a heat-resistant resin 2 made of colored polyallyl resin, and includes a body 3 formed in a substantially cylindrical shape and a body 3 extending upward from the body 3. It is formed from a mouth portion 4 whose diameter decreases toward the end, and a bottom portion 5 at the bottom of the body portion 3. Further, during biaxial stretch blow molding, only the mouth part 4 is molded without being stretched, and the mouth part 4 is formed to be thicker than the other parts of the container.

A threaded part 7 is formed in the mouth part 4 all around the circumferential direction from the open end 6 to the lower outer side thereof, and a support ring 8 is provided at the lower part of the threaded part 7.

In FIG. 1, the distribution state of the heat-resistant resin 2 is such that more than 90% of the heat-resistant resin 2 in the entire container is concentrated in the mouth 4, and the heat-resistant resin 2 is colored polyallyl resin. It was confirmed that only the mouth part 4 was colored, and the body part 3 was hardly colored.

Moreover, the distribution state of the heat-resistant resin 2 in the mouth part 4 is distributed on the outer circumferential surface from the opening end 6 to the upper part of the support ring 8 via the threaded part 7, and on the inner surface of the mouth part 4. 4 has a three-layer structure in which the intermediate layer is made of PET resin 1.

The distribution ratio of the heat-resistant resin 2 and the PET resin 1 at the mouth part 4 is such that the polyallyl resin as the heat-resistant resin 2 is 40%
PET resin 1 was 60% by weight. Furthermore, 50% or more of the heat-resistant resin 2 in the entire mouth portion 4 is distributed between the opening end 6 and the threaded portion 7, which particularly requires heat resistance.

Next, FIGS. 2 to 4 show a two-wheeled stretch-blow molded container having the same shape as the first embodiment. Another example in which the distribution state is different will be shown.

In any of the cases shown in FIGS. 2 to 4, the heat-resistant resin 2 is distributed in the portion from the opening end 6 to the support ring 8 and in the intermediate layer of the mouth portion 4. The remaining heat-resistant resin 2 is distributed on the inner surface of the mouth part 4 in the cases of FIGS. 2 and 3, and is distributed from the threaded part 7 in the cases of FIGS. 3 and 4. It is distributed even to the upper surface of the lower support ring 8 and provides the support ring 8 with heat resistance.

Moreover, the distribution ratio of the heat-resistant resin 2 and the PET resin 1 at the mouth part 4 was such that the heat-resistant resin 2 was in the range of 25 to 60% by weight in each case. Furthermore, in any case, more than 50% of the heat-resistant resin 2 occupying the mouth portion 4 extends from the opening end 6 to the threaded portion 7.
It was distributed between.

In addition, as in the case of the first embodiment, in all of FIGS. 2 to 4, more than 90% by weight of the heat-resistant resin 2 in the entire container was concentrated in the mouth portion 4.

Next, a method for manufacturing the polyester resin container of the first embodiment described above will be explained based on FIGS. 5 to 8. In the figure, 9 is a preform mold, 10 is a cavity, 11 is a main screw injection machine that injects the melt of PET resin 1 from the cavity gate 12 into the cavity 10, and 13 is the melt of heat-resistant resin 2 made of polyallylic resin. This is a sub-screw injection machine that injects into the cavity 10 from the cavity gate 12.

First, as shown in FIG. 5, the PET resin 1 is injected into the cavity 10 by the main screw injection machine 11. This is continuously injected by the stroke of the cylinder 14. In this PET resin injection process, after the start of injection, when the stroke advances and reaches a predetermined distance, the sub-screw injection machine 13 injects the heat-resistant resin 2 with the stroke of the cylinder 15, as shown in FIG. eject. During and after the injection of the heat-resistant resin 2, the PET resin 1 continues to be injected, and as shown in FIG.
It passes through the resin 1. Then, as shown in FIG. 8, the heat-resistant resin 2 reaches the tip of the cavity 10, the injection of the PET resin 1 is completed, and the preform 16 of the polyester resin container is molded.

Thereafter, this preform 16 is subjected to two-wheel stretch blow molding, as shown in FIG. 1, to obtain a polyester resin container.

As described above, in the first embodiment, since the mouth part 4 is made of 25 to 60% by weight of the heat-resistant resin 2 and 40 to 75% by weight of the PET resin 1, the heat resistance and gas barrier properties of the mouth part 4 are improved. In addition, since most of the body 3 is made of PET resin 1 with excellent transparency and the heat-resistant resin 2 is hardly distributed, the body 3 has excellent gas barrier properties as well as transparency. There is. Furthermore, since 50% or more of the heat-resistant resin 2 distributed in the mouth 4 is distributed to the opening end 6 and the threaded part 7, which particularly require heat resistance, the cap sealing performance of the mouth 4 is excellent. There is.

Next, a second embodiment will be explained according to FIG. Second
The polyester resin container of the example has a heat-resistant resin distributed in the mouth and the unstretched bottom part of the container, and as in the first example, PET resin 1 and colored polyallyl are used. The body part 39, the mouth part 4. It consists of a bottom part 5.

Further, in biaxial stretch blow molding, the center portion of the bottom portion 5 and the mouth portion 4 are formed unstretched and are formed thicker than the other portions of the container.

As shown in FIG. 9, the distribution of the heat-resistant resin 2 is concentrated in the unstretched mouth portion 4 and the unstretched portion 17 formed inwardly in a bowl shape at the center of the bottom portion 5. has been done. In the mouth part 4, as in the first embodiment, an open end 6 and a threaded part 7, which particularly require heat resistance for cap sealing performance, are provided.
The PET resin 1 is distributed in large numbers, forming a multilayer structure in which the intermediate layer is made of PET resin 1. Further, regarding the bottom portion 5, the heat-resistant resin 2 is distributed on the outer surface and the inner surface of the unstretched portion 17 in the center thereof, and the intermediate layer thereof is formed into a multilayer structure consisting of the PET resin 1.

It was also confirmed that the heat-resistant resin 2 was hardly distributed in the body 3 of the container, and that the mouth 4 and bottom 5 were colored with the colored heat-resistant resin 2.

In addition, as for the method of manufacturing the polyester resin container of the second embodiment, as shown in FIG. The PET resin 1 is then injected by the main screw injection machine 11 after 0.001 to 1.0 seconds. The following steps are carried out in the same manner as in FIGS. 5 to 8 of the first embodiment, and when the stroke of the cylinder 14 reaches a predetermined distance in the injection process of the PET resin l, the secondary screw injection machine is again used. 13, the heat-resistant resin 7 is injected, and the PET resin 1 is injected during and after the injection of the heat-resistant resin 2, and the heat-resistant resin 2 passes through the PET resin 1 and reaches the tip inside the cavity 10. .

After the injection of the PET resin 1 is completed, as shown in No. 11, the heat-resistant resin 2 is finally injected into the bottom of the cavity 10 to form a preform 16, which is biaxially stretched and blow-molded. The body 3 is heat-treated by heat setting to impart heat resistance, and a polyester resin container is molded.

As described above, in the case of a container having an unstretched part 17 in the bottom part 5, the second embodiment provides heat resistance to the open end 6 of the mouth part 4 and the unstretched part 17 of the bottom part 5, which particularly require heat resistance. By intensively distributing the thermoplastic resin 2 and imparting heat resistance,
The cap sealing performance of the mouth portion 4 and the self-supporting stability of the container can be improved at the same time, and since the body portion 3 is mostly made of PET resin 1, it has excellent transparency and gas barrier properties.

(Effects of the Invention) As is clear from the above description, in the present invention, more than 90% of the heat-resistant resin in the entire container is concentrated in the mouth, and most of the body is made of polyethylene terephthalate resin. The body has excellent transparency and gas barrier properties, and more than 50% of the heat-resistant resin distributed in the mouth is concentrated in the opening end and threaded part, which particularly require heat resistance, so the cap seal for the mouth is excellent. This has the effect of providing a synthetic resin container with excellent properties.

In addition, since the mouth part of the present invention is made of a heat-resistant resin of 25% by weight or more and a polyethylene terephthalate resin of 40% by weight or more, the mouth part is made of synthetic resin that can simultaneously ensure heat resistance and gas barrier properties. It has the effect of providing a container.

Furthermore, in the case of a container having an unstretched part at the bottom, the present invention can improve the heat resistance of each by distributing a heat-resistant resin in the open end of the mouth and the unstretched part at the bottom. The present invention has the effect of providing a synthetic resin container which has excellent cap sealability at the mouth, little thermal deformation at the bottom, and excellent self-sustaining stability.

[Brief explanation of drawings]

1 to 8 show the first embodiment, and FIG. 9 and the first embodiment show the first embodiment.
FIG. 1 shows a second embodiment. FIG. 1 is a sectional view showing an example of a synthetic resin container according to the first embodiment, and FIGS. 2 to 4 are sectional views of the opening of a synthetic resin container showing other embodiments of the first embodiment. FIGS. 5 to 8 are explanatory diagrams illustrating the method of manufacturing the synthetic resin container of the first embodiment. FIG. 9 is a sectional view showing an example of a synthetic resin container of the second embodiment, and FIGS. 10 and 11 are explanatory diagrams illustrating the manufacturing method of the second embodiment. 1... Polyethylene terephthalate resin 2... Heat resistant resin 3... Body part 4... Mouth part 5... Bottom part 6... Open end 7... Threaded part 8... Support ring 17 ...Unstretched part FIG, 1 ゝ---~5

Claims (1)

[Claims] 1. A polyester resin container comprising a mouth, a body, and a bottom, the mouth having a threaded part and a support ring, wherein the mouth is made of polyethylene terephthalate resin and heat-resistant resin. 90% or more of the heat-resistant resin in the entire container is distributed in the mouth, and 50% or more of the heat-resistant resin in the mouth is concentrated between the opening end and the threaded part. A polyester resin container characterized by: 2. The polyester resin container according to claim 1, wherein the mouth portion is made of 40 to 75% by weight of polyethylene terephthalate resin and 25 to 60% by weight of heat-resistant resin. 3. A polyester resin container consisting of a mouth, a body, and a bottom, and having an inwardly bowl-shaped unstretched part in the bottom, at least the open end of the unstretched part of the mouth and at least the bottom. A polyester resin container characterized in that a heat-resistant resin is distributed in an unstretched part. 4. The polyester resin container according to claim 1 or 3, wherein the heat-resistant resin is polyallyl resin, polyethylene 2,6 naphthalate, or polyethylene 1,5 naphthalate.