JPH03200534A - Polyester bottle - Google Patents

Abstract

PURPOSE:To prevent a transparent part from being folded by a method wherein a specific heat-shrinkable polyester film is formed into a tubular label, at least one side of either or both ends of the label is put into print, so that the transparent part is given a specific dimension axially, and the transparent part is coated with a transparent organic high-molecular resin. CONSTITUTION:A heat-shrinkable polyester film 1 has a carry-over heat shrinkage percentage of 57-63%, a shrinkage stress of 1.0-1.8kg/mm<2> and a heat shrinkage percentage of 15-33% at 65 deg.C. The label is formed into a tubular configuration and put into print 2, so that a transparent part formed at either or both ends of the label is given an axial width of at least 1.5mm, and a transparent coat layer 3 is formed on the transparent part. The resin intended for use in the coat layer, if capable of being coated on the film, is adequate for the purposes and, for example, nitrocellulose and polyamide resin may be used. In this manner the difference in shrinkage rate between the transparent part and the printing part is minimized, whereby the folding of the transparent part after the heat shrinkage can be prevented.

Description

DETAILED DESCRIPTION OF THE INVENTION [Industrial Field of Application] The present invention relates to a polyester bottle, and more particularly to a polyester bottle equipped with a heat-shrinkable polyester label.

[Conventional technology] Compared to conventional glass bottles, polyester bottles have
Because it has excellent mechanical strength and is lightweight, demand is increasing, mainly for relatively large-capacity soft drink bottles. A heat-shrinkable film is generally used as a label for the polyester bottle, and even when packaging an irregularly shaped bottle or the like, it is relatively easy to provide a beautiful packaging appearance. Materials for such heat-shrinkable films include polyester and polyvinyl chloride.

Examples include polystyrene, polypropylene, etc. In particular, polyester film has the same texture as the polyester bottle that is being packaged and has excellent mechanical strength, so it is one of the most suitable films for polyester bottle labels. Although it has been put into practical use, there is still room for improvement as described below.

First, to explain the label manufacturing process, 1) First, label printing is performed intermittently at regular intervals on one side of a sheet-shaped heat-shrinkable polyester film; 2) Next, the sheet-shaped heat-shrinkable polyester film is printed on Separate each unit label individually by cutting at the untreated transparent part, ■ Attach both sides of the bell to form a cylinder, and ■ Cover the polyester bottle at a predetermined position and heat shrink it to create a label. are being installed. However, at present, as shown in FIG. 2, the transparent portions left as non-printing portions at the upper and lower ends of the cylindrical label curl inward and bend, spoiling the appearance of the polyester bottle.

[Problems to be Solved by the Invention] The present invention has been made in view of the above circumstances, and provides a polyester material to which a heat-shrinkable polyester label is attached with a printed heat-shrinkable polyester label leaving a transparent portion at the edge. This is a polyester bottle with no bending in the transparent portion at the end of the heat-shrinkable polyester label.

[Means for Solving the Problems] The present invention that solves the above problems is a polyester bottle in which a cylindrical heat-shrinkable polyester film is wrapped around a polyester bottle, and the achieved heat shrinkage rate is 57 to 63.
%. Shrinkage stress is 1.5-1.7Kg/ml', 6 5
A cylindrical label made of a heat-shrinkable polyester film with a heat shrinkage rate of 15 to 33% at °C, so that the transparent part is 1.5 mm or less in the axial direction on at least one side of either or both of its ends. The gist is that the transparent part is coated with a transparent organic polymer resin and then attached to a polyester bottle by heat shrinking.

[Function] As a result of extensive research, the present inventors found that the curl that occurs during heat shrinkage is due to the difference in heat shrinkage speed between the transparent part and the printed part, and came up with the present invention. It became a thing.

Figure 3 is a schematic cross-sectional explanatory diagram showing the state when a heat-shrinkable polyester label is heat-shrinked and attached to a polyester bottle. When applied, the printed part 5 where the printing ink is laminated receives a reinforcing effect from the printing ink, and since the printing ink itself does not exhibit heat shrinkage, there is a difference in thermal behavior between the printed part 5 and the plain transparent part 4. occurs. That is, on the same label made from the above-mentioned heat-shrinkable polyester film, a part with a fast shrinkage speed (transparent part 4) and a part with a slow shrinkage speed (printed part 5) are formed, and when the shrinkage is finished, as shown in FIG. As shown in the figure, a C bend occurs.

Therefore, the inventors of the present invention conducted repeated studies to minimize the difference in shrinkage speed between the transparent part 4 and the printed part 5, and found that the axial dimension of the transparent part was set to 1.5 mm or less, and the transparent part was coated with resin. By forming a transparent coat layer,
This prevents folding after heat shrinkage.

As for the resin used for the transparent coating layer, any resin that can be coated on a heat-shrinkable polyester film can be used, such as nitrocellulose, boria resin, etc. Polyester resin. Polyurethane resin. Vinyl chloride resin, rubber resin. An appropriate selection may be made from organic polymer resins such as acrylic resins depending on conditions such as the type and thickness of the printing ink.

FIG. 1 is a schematic cross-sectional view of a heat-shrinkable polyester label attached to a polyester bottle according to the present invention, and a transparent coat layer 3 is formed on the transparent portion. However, the present invention is not limited to the example shown in FIG. 1, and the transparent coat layer 3 may be formed on at least a part of the transparent part, so it may be formed on a part or all of the printed part and the transparent part. Various embodiments are possible by combining the above.

The heat-shrinkable polyester film applied to the present invention has an ultimate heat shrinkage rate of 57 to 63% and a shrinkage stress of 1.0 to 1.
．． 8 Kg/+*m", the heat shrinkage rate at 65°C is required to be 15 to 33%, and in the case of a label in which the above-mentioned heat-shrinkable polyester film is formed into a cylindrical shape, the heat shrinkage rate at both ends of the label It is necessary that the width dimension of the transparent portion formed on one or both of them is 1.5 mm or less.

[Example] The achieved thermal shrinkage rate is 60% and the shrinkage stress is 1.3 g/am2
One side of a 45 μm polyester film with a heat shrinkage rate of 20% at 65°C is printed with a thickness of 2.5 μm, and both the top and bottom edges are printed! , a label with a transparent part of 5 mm width was produced. On the transparent part of the printed side of the above label, 1.
A test piece of the present invention was obtained by coating a polyamide transparent resin with a thickness of 5 μm to form a cylindrical shape.

Next, a label with a transparent portion having a width of 3 mm was prepared and used as a comparative test piece. The above test piece was heated at 140° C. for 6 seconds to undergo heat shrinkage, and then the transparent portion was checked for curl. Curl in the transparent portion was evaluated by visual inspection, and if even one bend was observed at the tip in the circumferential direction, it was determined that curl had occurred. The results are shown in Table 1.

- The above label before being formed into a cylinder shape was heated at 140°C, and the heat shrinkage rates of the transparent part and the printed part were measured by the following method 1 second, 3 seconds, and 6 seconds after the start of heat shrinkage. The difference in thermal shrinkage rate was determined. The results are shown in Table 2.

[Heat shrinkage rate] When the label is formed into a cylindrical shape, measure the length in the circumferential direction, and calculate the length before heating. When the length after heat shrinkage is A, il −j2°×100 l is the heat shrinkage rate (%).

Table 1 Table 2 In the example, the axial dimension of the transparent part is formed to be 1.5 cm or less, and the heat shrinkage rates of the printed part and the transparent part are almost equal, so the heat shrinkage at 1 second and 3 seconds after the start of heat shrinkage is The difference in shrinkage rate is small, and no curls are seen in the transparent part. On the other hand, in the comparative example, which is a conventional heat-shrinkable label, complete bending occurred because the difference in heat-shrinkage rate was particularly large one second after the start of heat-shrinkage.

[Effects of the Invention] Since the present invention is configured as described above, it is possible to prevent the transparent part from folding inward, which occurs when labeling polyester bottles, thereby improving the aesthetic appearance of the product. We were able to increase the value.

[Brief explanation of drawings]

Figure 1 is a reference sectional view showing a typical example of a heat-shrinkable polyester label attached to a polyester bottle of the present invention, Figure 2
The figure is a reference external view showing the curled state when labeling a polyester bottle with heat-shrinkable polyester film.
FIG. 3 is a state explanatory reference diagram showing changes over time of a heat-shrinkable polyester label. 1... Heat shrinkable film 2... Printing ink 3.
...Transparent coat layer 4...Transparent part 5...Printed part

Claims (1)

[Claims] In a polyester bottle formed by wrapping a cylindrical heat-shrinkable polyester film around a polyester bottle, the achieved heat shrinkage rate is 57 to 63% and the shrinkage stress is 1.0 to 1.8.
kg/mm^2, heat shrinkage rate at 65℃ is 15-33
A cylindrical label made of a heat-shrinkable polyester film of 10% is printed on at least one side of either or both of its ends so that the transparent part is 1.5 mm or less in the axial direction, and the transparent part is A polyester bottle characterized by being heat-shrinkable and attached to a polyester bottle coated with an organic polymer resin.