JPS6045154A - Polyester resin composite vessel and manufacture thereof - 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 polyester resin composite container, particularly a bottle, and more particularly to a container with improved gas barrier properties and light shielding properties. The invention also relates to a method of manufacturing such a container.

Containers made by molding saturated polyester resins such as polyethylene terephthalate (hereinafter referred to as IPETJ), especially bottles made by biaxial stretch blowing, have excellent toughness, transparency, surface gloss, moisture impermeability, and resistance. It has excellent chemical resistance and internal pressure resistance, and has characteristics that are generally advantageous for packaging containers. For this reason, it is used in a wide range of fields, including food, detergents, and cosmetics.

However, PE knife has insufficient barrier properties against gases such as oxygen and balate gas, depending on the application.

When used as containers for contents that are easily affected by oxygen, such as fruit juice, sake, wine, mayonnaise, ketchup, etc., the storage period is short and there are major practical limitations. The same applies to containers for carbonated drinks such as Yabir, and only large containers with a capacity of 12 or more are in practical use. Small-capacity containers are disadvantageous due to the relationship between surface area and volume, and cannot be used unless they are made extremely thick.

Measures to improve the gas barrier properties of PET containers include applying vinylidene chloride resin by coating, spraying or dipping, and applying synthetic resins such as ethylene-vinyl acetate copolymer and polyacryloyl di-1-lyl. Lamination is proposed.

One object of the present invention is to use PE with improved gas barrier properties.
The purpose of this product is to provide a T-container, especially a bottle, and its features include the use of aluminum foil, which has high barrier properties and light-shielding properties, and the fact that it is provided on the body of the container.

That is, the polyester resin composite container of the present invention, as shown in FIG. It is something.

The seal part 11 has a shape suitable for sealing M (not shown), and the form of the lid is an aluminum sheet crank cap, a screw cap, a rolled seal, or aluminum foil and synthetic resin. There are various types such as heat sealing of laminated materials.

The structure of the body part 13 is as shown in the enlarged cross-sectional view of the inside of the circle in FIG.
2. There is a barrier layer 2 consisting of aluminum foil 21 and an auxiliary layer 23 of paper or any synthetic resin.

The shape of the container may, of course, be arbitrarily selected from the cylindrical shape shown in the drawings, as well as a truncated conical shape, within the range that can be realized by biaxial stretch blow molding.

The barrier performance of the polyester resin composite container of the present invention is as follows:
It goes without saying that the greater the coverage of the outer surface area of the container by one layer of the barrier, the higher the coverage, but by increasing the thickness of the uncoated part,
By setting it to 111111 or more, the barrier performance of that part can be brought to a substantially satisfactory level, so it is usually sufficient to set the coverage to 50% or more.

Now, let us consider the case where a single PET container is made into a composite container according to the present invention, and the gas barrier properties are to be increased by a factor of .chi. (that is, the gas permeability is reduced to 1/.chi.).
If the gas permeation rate of a single container is υo CC/24 hours (1 atm, 23°C, RH 100%), then in order to achieve the gas permeation rate of a composite container υ' = υO/χ, the coverage ratio x should be
-(1-1/χ)X100 (%) J: Yes. In addition, the wall thickness of the single container is t at the body.
o, and tl at the shoulder and bottom, then in a composite container, the body wall thickness covered with one layer of barrier is t' o =to-0,3
If the excess PET resin is added to the uncoated shoulders and bottom to make it thicker, the thickness can be increased by (to-0,3)/(1-χ) on average. The resulting effect of improving the barrier properties can be seen as a reduction in the amount of gas permeation to υ″=υ○/χ×t1/(tl+(t o-0,3/(-1-χ)).

In this way, the PET composite container of the present invention can easily have a barrier performance 2 to 3 times that of a single container by providing a single barrier layer, and by thickening the non-coated portion, Furthermore, barrier performance can be improved.

By increasing the coverage rate, the PET resin in that area can be thinned and used to thicken the uncoated area, so even higher barrier performance can be achieved with the same resin-using device.

The use of aluminum foil improves its light-shielding properties, and since light actually only enters from the shoulders, deterioration of the contents due to the action of ultraviolet rays can be significantly suppressed.

Because the barrier layer does not cover the entire surface of the container, there is a boundary between coated and uncoated portions of the outer surface of the container. For both aesthetic and handling reasons, this boundary should preferably be level-free, and any level differences due to changes in wall thickness should be provided on the inner surface of the container. Such a container can be manufactured by the manufacturing method described below.

The design of the container of the present invention is enhanced by the auxiliary layer of the barrier layer described above. That is, when paper is used as the auxiliary layer, printing may be performed on its surface. When using a transparent synthetic resin film, a printing layer is provided between it and the aluminum foil.

Printing with an aluminum foil background produces a metallic design effect, increasing product value.

Another object of the present invention is to provide a method for manufacturing the above-mentioned polyester resin composite container with high productivity. In the manufacturing method of the present invention, as shown in FIG. 2, first, a cylindrical blank 3 with both ends open made of a laminated barrier material consisting of at least aluminum foil and hot melt adhesive is prepared and placed in a blow mold 4. . On the other hand, P
A bottomed cylindrical or conical parison 5 is formed by injection molding of ET resin, as shown in FIG.
Biaxial stretching blowing is performed within the blow mold 4 described above. The hot parison expands by blowing, presses the barrier material blank 3 against the inner surface of the mold 4, and joins and integrates it with the blank 3 to form the composite container 1. As shown in FIG. 4, when this is released from the mold 4, a product is obtained.

As described above, the material for the barrier layer is made by laminating paper or any synthetic resin film to aluminum foil by dry lamination, wet lamination, or extrusion coating using an adhesive, as desired.

The hot melt adhesive may be applied to the aluminum foil surface by melting or solvent coating.

The blank is formed by cutting or punching the required material and rolling it according to the shape of the barrel. Insert into the blow mold using an appropriate inserter.

Prior to biaxial stretch blow molding, the blow mold was
Adjusting the temperature to 0° C. and heating the blank is recommended to ensure hot melt bonding between the barrier layer and the PET resin.

The injection molded parison is made into a strong container by biaxial stretching blowing at a temperature suitable for stretching the PET resin, that is, 90 to 100°C.
′ At this time, the conventional method is to leave residual heat in the parison to adjust the temperature after injection molding of the bottomed parison, and then perform stretch blow molding, but after index molding, the bottomed parison is once cooled to near room temperature. Alternatively, the material may be heated after heating to give an appropriate temperature. However, in any case, it has been experienced that the shorter the time that the surface of the injection molded bottomed parison is exposed to air, the better the hot melt bonding with the barrier layer material. Therefore, it is preferable to cool the injection-molded bottomed parison to a temperature at which it can be released from the injection mold, then rapidly cool it to a temperature suitable for stretching, and then stretch-blow it.

Blow air preferably has a high pressure, but 10 to 25 KCI/c
m2 provides sufficient bondability and smoothness of the Wim/uncovered portion boundary. Other conditions may follow known techniques regarding biaxial stretch blow molding of PET resin.

By blowing the PE towards the barrier layer material blank.
When the T resin parison expands, as shown in Figure 5,
Since the blank 3 is bonded so as to be buried in the PET resin 12.14, there will be no step difference at the boundary between the covered part and the non-covered part. Advantage J: When attempting to sleep, the barrier layer blank is extended beyond the maximum diameter part of the body, and in the example shown, is also partially present at the shoulder 12 and the bottom 14. In this case, , blank (other edges need to be slightly deformed. Therefore, the aluminum foil should be of high purity, e.g. 99.3% or higher, soft material, preferably 99.8% or higher).
It is preferable to use an ultra-soft material with a content of 5% or more.

Example full filling Yong Kong 190CC1 filling capacity 1ΩOCC, diameter 53
A wide-mouth cylindrical container having the shape shown in FIG. 1 and having a maximum body diameter of 54 mm was manufactured.

The structure of the barrier layer is PET (25μ>/A×9μ).
/Hot melt adhesive (3μ), body diameter 53n+m
A cylindrical blank was prepared and placed in a blow mold heated to 80°C.

PET resin with IV111!0.72 was used as the material, and the date was set at 180. A bottle with a flat diameter wall thickness of 0.4 mm for the body, an average wall thickness of the shoulder and bottom parts of Q, 9 mm, and a barrier coverage of 74% was molded by biaxial stretching blowing, and heat treated in the mold. The strain was removed and the joint was made perfect before being taken out.

The amount of oxygen gas permeated was 0.38 CC/piece (24 hours, 1
(atmospheric pressure, 23° C., 100% RH), whereas the above composite container according to the invention had 0.15 CG/bottle.

When this container was filled with hot water at 73° C., the volume shrinkage was 1% or less, indicating that it had sufficient hot fill suitability.

[Brief explanation of the drawing]

FIG. 1 shows an example of the polyester resin composite container of the present invention, with the middle half being a side view and the middle half being a longitudinal sectional view. 2 to 4 are cross-sectional views illustrating the steps of the method for manufacturing a polyester resin composite container of the present invention. FIG. Figure 3 shows the stage in which biaxial stretch blow molding is being carried out, and Figure 4 shows the stage in which the composite container with a single barrier layer is taken out at the same time as biaxial stretch blow molding. are shown respectively. FIG. 5 is a partial cross-sectional view showing the bonding pattern between a barrier layer and a polyester resin layer in a composite container. 1...Composite container 13...Body part 2...
...One layer of barrier 3...Blank with one layer of barrier 4...Blow mold 5...Applicant for bottomed parison patent Dai Nippon Printing Co., Ltd. Agent Patent attorney Su Souo Ka

Claims (7)

[Claims] (1) A composite container made of polyester resin, which is a container manufactured by two-wheel stretch blow molding of polyester resin, and has a barrier layer containing aluminum foil on the body. (2) The coverage rate of one barrier layer is 50% of the outer surface area of the container.
% or more, and the uncoated portion has a wall thickness of 0.3 mm or more. (3) The container according to claim 1 or 2, in which there is no step on the outer surface of the container caused by providing a single barrier layer at the boundary between the coated portion and the uncoated portion. (4) Prepare a cylindrical blank with both ends open made of a laminated barrier material consisting of at least aluminum foil and Botmelt adhesive, place it in a blow mold, mold a bottomed parison by injection molding of polyester resin, and mold it into the mold described above. A method for manufacturing a polyester resin composite container, which comprises the steps of performing biaxial stretch blow molding in a mold, joining blanks of the barrier material described above at the same time as molding, and releasing the molded product. (5) In biaxial stretch blow molding of polyester resin, after molding a bottomed parison by injection molding, the mold is released from the injection mold once cooled to a temperature that can be released from the mold, and then the bottomed parison is rapidly heated to a temperature suitable for stretching. 5. The manufacturing method according to claim 4, which comprises cooling the material to a temperature of 100%, placing it in a blow mold, and performing biaxial stretching blowing. (6) The manufacturing method according to claim 4 or 5, wherein the humidity of the blow mold is adjusted prior to biaxial stretch blow molding of the polyester resin, and the barrier material blank placed inside the mold is heated. (7) The production according to any one of claims 4 to 6, in which soft aluminum foil with a purity of 99.3% or more, preferably ultra-soft aluminum foil with a purity of 99.85% or more is used as the aluminum foil. Method.