JPS5974061A - Bottle and its manufacture - Google Patents

Abstract

(57) [Summary] This bulletin contains application data before electronic filing, so abstract data is not recorded.

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a polyethylene terephthalate bottle and a method for producing the same, and more particularly to a stretch-blow-molded polyethylene terephthalate bottle having a gas parrying coating formed at least on the inner surface and a method for producing the same.

A polyethylene terephthalate polymer formed by biaxial stretching and blow molding from a bottomed E-lison (herein, it includes an ethylene terephthalate copolymer containing ethylene terephthalate as a main component and a blend containing polyethylene terephthalate as a main component) (called polyethylene terephthalate) has gas barrier properties, transparency, i
It has excellent container properties such as il impact resistance, and has recently been put into practical use for storing various contents. However, when filling and sealing contents containing pressurized carbon dioxide gas, such as beer or carbonated drinks, over time some carbon dioxide gas is lost by permeating through the thin shoulders and body walls. On the other hand, a small amount of oxygen penetrates through the wall and tends to damage the flapper containing the contents.

As a countermeasure, a method has been proposed in which a coating film made of vinylidene chloride copolymer, for example, is formed on the inner and/or outer surface of the bottle to have excellent barrier properties against carbon dioxide gas and oxygen, but depending on the shape of the bottle, (For example, if embossments or beads are formed), uncoated areas or very thin areas of the coating may occur, resulting in insufficient peeling properties of the kittle as a whole, or unsatisfactory adhesion of the coating. However, the problem arises that the coating film tends to swell and crack over time after filling and sealing.

When forming the above coating film on i9 Rison, ・'1? ,I
This is presumably due to the fact that the shape of the mold is generally monotonous and the adhesion is improved by heating to, for example, close to 100° C. before stretching and blow molding, but the above problem is unlikely to occur.

As a method of forming a coating film on the inner surface of the bottomed Yarnun, hold the Nollison upside down so that the mouth is facing downward, and use Z9IJ.
After inserting the nozzle into the inside of the parinon and spraying the paint, leave it for a while to let the paint adhering to the inner surface flow down and drain it, then blow heated air into the inside of Parinon to dry the film of paint remaining on the inner surface. A method has been proposed. However, in this case, the paint that had flowed down from the woman remained in the vicinity of the mouth, especially on the edge of the mouth, in a wavy form, that is, in patches of thick and thin parts, and even after drying, the paint remained in the vicinity of the mouth, especially on the edge of the mouth. As a result, there arises a problem in that the sealing performance after the bottle formed from the eIJson is capped is likely to be impaired.

It is an object of the present invention to solve the problems of the prior art described above.

In order to achieve the above object, the present invention is characterized in that a guzzle coating film is formed on the inner surfaces of at least the shoulder, body and bottom parts, and the coating film is not formed on the end face of the mouth part. Stretch-blow molding yh? The present invention provides a polyethylene terephthalate bottle.

Furthermore, the present invention provides a method for filling a parison with a bottomed polyethylene terephthalate with its mouth facing upward, and (a) filling the parison with a water-based paint whose dried paint film has sparring properties at least up to the level of the support ring. After sucking up the filled paint, or (mouth) coating the inner surface of the parison at least up to the level of the support ring, and after coating, sucking up the paint accumulated inside the parison. After raising it, heated air is blown into the i9IJ son under the above conditions to dry the film of the paint remaining on the inner surface of the jar, and the bottomed fIJ son on which a coating film has been formed.
The present invention provides a method for producing polyethylene terephthalate (yl-'), which comprises heating the polyethylene terephthalate to a stretching temperature and then stretching and blow molding to form a polyethylene terephthalate (yl-').

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

In Figures 1, 2, 3, and 4, is the bottom of the J line higher than ethylene terephthalate? lison, typically formed by injection molding methods. 2 is the mouth, 3
4 is a threaded portion, and 4 is a support ring, which retains its original shape and thickness even after being formed into a bottom 15 (FIG. 6) by stretching and blow molding. The support ring 4 engages with a support (not shown) when capping the screw part 3, and the axial force due to capping is applied to the shoulders 15a and 15 of the bottle 15, which have relatively small strength. Body part 15b and bottom part 1
This is usually provided to prevent the effect on 5C.

a substantially hanging portion below the support ring 4 of the parison 1;
That is, the body 4 mainly becomes the relatively thin shoulder 15a and body 15b of the formed bottle 15. The bottom 6 of the parison 1 becomes primarily the bottom 15c of the bottle 15 formed.

Therefore, in order to improve the spalling properties of the formed & Bye.

Since the upper part of the support ring 4 remains thick (for example, about 1 to 4 inches thick) even after it is formed into a bottle, it does not necessarily need to be coated with a gas barrier coating. On the contrary, during this coating operation, the paint often adheres non-uniformly to the end surface 2a of the mouth portion 2, which tends to result in poor sealing as described above, so it is preferable not to cover the above-mentioned upper portion.

As shown in Fig. 1, the dry coating film 1 is exposed to gas (oxygen, nitrogen, carbon dioxide, etc.) barrier properties through the nozzle 7 with the mouth 2 facing upward and the nails erect. at least up to the level of the support ring 4. This type of paint includes a copolymer consisting of a vinylidene chloride monomer and an acrylic monomer or a methacrylic monomer, or a vinylidene chloride monomer,
Examples include aqueous latexes of copolymers made of acrylic or methacrylic monomers and ethylenically unsaturated monomers.

Next, as shown in Figure 2, keep the royal position as it is and suck it up.
is inserted into the OIJ container 1 up to the vicinity of the bottom 6, and the filled paint 8 is sucked up to remove most of the paint 8 from the OIJ container 1. Even after being sucked up once, the paint flows down the inner surface 5a of the body 5 and some paint accumulates near the bottom 6, so about 15 to 30 seconds have passed after the first suction. Then, almost all of the accumulated paint 8 is sucked up again by the suction pipe 10, as shown in FIG.

By doing so, NoJ? A paint film 8a having a relatively uniform thickness is formed along the inner surfaces of the body portion 5 and bottom portion 6 of the IJ unit 1.

Next, while in the same upright position, as shown in Figure 4, insert the air nozzle 11' into the parison 1 and blow heated air 12 at about 100°C into the parison 1 to form a paint film 8a. After drying, a yarn 1 with a dry coating film 13 formed on the inner surface is obtained. The thickness of the coating film 13 obtained in one operation is usually about 1
Since it is 0 to 20 ttrn, if a thicker coating film is to be obtained, the above operation may be repeated.

The wicked paint is recycled and reused for the next coat of OIJson.

FIG. 5 shows an example of a method in which instead of filling the paint 8, the paint is sprayed from a hole 14a provided at the tip of the paint nozzle 14 to coat the inner surface 5a of the body 5. .

The paint nozzle 14 rises to fill the hole 14. When a reaches approximately the level of support/g4, injection is stopped. The smear 8 attached to the inner surface 5 flows down and accumulates near the bottom 6, so it is sucked up and/or piped 9 and/or
It still sucks up by 10. The subsequent operations are similar to those for filling.

If necessary, a gas parrying coating may be formed on the outer surface of the coating by dipping, spraying, etc. before or after the inner surface coating.

As described above, the body part 5 and bottom part 6 of the parison 1 coated with the gas parison coating film 13 are uniformly heated to a stretching temperature (usually about 70 to 110 degrees Celsius, preferably about 80 to 100 degrees Celsius) by infrared rays or the like. 7Jla. After that, the bottle 15 is manufactured by biaxial stretching and blow molding using a conventional method.At this time, the coating film 13 becomes thinner in proportion to the increase in surface roughness. By making the coating film 13 appropriately thick, the bottle 15 has excellent force dispersion properties (the preferred thickness of the coating film 13 on the bottle is about 1 to 30 μm).
m) is obtained.

The RF toller of the present invention has the advantage of having excellent barrier properties against gases such as oxygen and carbon dioxide, since a gas barrier coating film is formed on the inner surfaces of at least the relatively thin shoulders, body, and bottom. have Furthermore, since the above coating film is not formed on the end surface of the mouth, the coating film of uneven thickness may cause ? 1. There is no risk of damaging the sealing properties of the container. have an effect.

Further, according to the method of the present invention, it is possible to freely determine the level at which the coating film is formed on the inner surface of the container, and therefore it is possible to easily manufacture a container in which the end surface of the mouth portion is not coated with a coating film. This effect is achieved. Further, the formed coating film has the advantage of being relatively uniform in thickness and having excellent adhesion.

[Brief explanation of the drawing]

Figure 1 is a vertical cross-sectional view showing the state in which the paint is filled in the parison, Figure 2 is a vertical cross-sectional view showing the state in which the filled paint is being sucked up, and Figure 3 is a vertical cross-sectional view showing the paint being sucked up into the parison. Figure 4 is a vertical cross-sectional view showing the state in which the paint that has accumulated is being sucked up.
'f'I) A longitudinal cross-sectional view showing a state in which a film of paint remaining on the inner surface of the non-contact material is dried; FIG. 6 is a partially cutaway front view of an it' which is an embodiment of the present invention. 1... Bottomed A-lison, 2a... Mouth end surface, 4...
Support ring, 6... Bottom, 8... Paint, 8a... Paint film, 12... Heated air, 13... Dry paint film, 1
5...yr}, 15a...shoulder, 15b...torso, 15C...bottom.

Claims (3)

[Claims] (1) Stretched and blow-molded polyethylene terephthalate, characterized in that a gas barrier coating film is formed on the inner surfaces of at least the shoulder, body and bottom parts, and the coating film is not formed on the end face of the mouth part. Bottle. (2) Bottomed eI made of polyethylene terephthalate
With the mouth of the J-non facing upward, fill the water-based paint with a dry film with gas parrying properties into the container up to at least the level of the support ring, and after sucking up the filled paint. , In the above state, the heated air is connected to the OIJ.
A bottomed parison with a paint film formed by blowing the paint into a cylinder and drying the paint film remaining on the inner surface of the parison is heated to a stretching temperature, and then stretched and blow-molded to form a bottle. A method for manufacturing a polyethylene terephthalate bottle, characterized by: (3) / With the mouth of a bottomed parison made of polyethylene terephthalate facing upward, coat the inner surface of the parison with a water-based paint whose dried film has gas barrier properties up to at least the level of the support ring; After coating) P
After sucking up the paint accumulated in the iPIJ son, heated air is blown into the iPIJ son under the above conditions to dry the film of the paint remaining on the inner surface of the iPIJ son, thereby forming a coating film. 1. A method for producing a polyethylene terephthalate bottle, which comprises heating the bottomed bottle to a stretching temperature and then stretching and blow-molding it into a bottle.