JPH0430098Y2 - - Google Patents

Description

[Detailed Description of the Invention] [Industrial Field of Application] The present invention relates to a composite sheet for forming a sleeve having a viewing window used for covering and protecting glass bottles and the like.

[Conventional technology]

BACKGROUND ART Conventionally, a sleeve made of a heat-shrinkable synthetic resin sheet is placed over the outer surface of a glass bottle and heated to shrink the sleeve and protect the glass bottle. In many of these cases, for example, non-foamed films are printed on the entire surface, and foamed sheets or coextruded sheets are not transparent, so they cannot be filled into bottles. It was very difficult to visually check the remaining amount of the contents (residual capacity) from the outside of the bottle.

In the case of non-foamed films, such problems can be easily solved by providing a non-printed transparent part in the longitudinal direction of the bottle, that is, in the direction perpendicular to the flow during film production. On the other hand, in the case of foamed sheets or coextruded sheets, the inside of the bottle can be visually inspected after shrinking by cutting out rectangles, circles, slits, etc. in the longitudinal direction of the bottle, that is, in the direction perpendicular to the flow direction during manufacturing of the sheet. It was thought that a "peephole" would be formed that would allow for observation.

[Problem that the invention attempts to solve]

However, in the case of foamed sheets or coextruded sheets, when a partially slit-shaped sleeve is placed over a bottle and heated, the shrinkage force generated in the flow direction of the sheet causes cracks to form at the cut-out portion. This caused the sleeve to tear or become twisted, resulting in a disadvantage that the appearance was significantly impaired. Therefore, we conducted extensive research to see if we could solve the problem of "peepholes", which were difficult to provide in single foam sheets or coextruded sheets, by taking advantage of the characteristics of both heat-shrinkable foam sheets and non-foamed films. result,
This is what led us to the present invention.

[Means for solving problems]

This device has a transparent part that is not intentionally printed on the printing surface, has a thickness of 20 to 40μ, has a heat shrinkage rate of 60 to 80% (140℃) in the flow direction, and a heat shrinkage rate of 10% in the direction perpendicular to the flow direction. ~30% (140℃) non-foamed polystyrene film and a foamed polystyrene sheet cut out in a shape that matches the transparent part of the non-foamed polystyrene film on the printing surface side, and a printing ink with adhesive properties (ability). (used for film printing) to ensure that the unprinted transparent part of the non-foamed polystyrene film matches the part cut out from the foamed polystyrene sheet, and also to ensure the flow between the non-foamed polystyrene film and the foamed polystyrene sheet. To provide a shrinkable composite sheet for forming a sleeve, which has a window through which the remaining capacity of the contents can be visually observed when the sheet is adhered in the same direction and is shrunk into a glass bottle.

The reason for limiting the thickness of the foamed polystyrene sheet to 0.2 to 0.4 mm is that if it is less than 0.2 mm, the shock absorption power is too small, and if it exceeds 0.4 mm, it will easily break due to deformation, and it will not bend when wrapped around a bottle. Because it will be easier for me to enter.

The thickness of non-expanded polystyrene film is 20~40μ
The reason for this is that if the thickness is less than 20μ, sufficient film strength cannot be obtained, and if it exceeds 40μ, no merit in terms of strength is observed.

In order for the sheet to shrink efficiently, both non-expanded polystyrene film and expanded polystyrene sheet must have a heat shrinkage rate of 60 to 80% in the machine direction (140℃).
It is necessary to have a contractility of . The heat shrinkage rates of both materials need to be approximately equal because the non-foamed polystyrene film, which has a transparent portion that is not intentionally printed, and the die-cut portion of the foamed polystyrene sheet are laminated so that they coincide.

The present invention will be explained below based on the drawings.

Fig. 1 is a perspective view showing the state of the shrinkable composite sheet for forming a sleeve having a viewing window according to the present invention after shrinking it into a bottle, and Fig. 2 shows the structure of the sheet at the die-cut portion in Fig. 1. FIG.

1 in Figure 2 is a non-expanded polystyrene film,
2 is a printed surface (part) with ink having adhesive properties, 3 is a foamed polystyrene sheet, and one side of the non-foamed polystyrene film 1 is coated with adhesive properties.
Printing 2 of product names, patterns, prices, bar codes, etc. is performed using ink having the following properties, but a transparent part 4 where no printing is intentionally applied is provided in a part corresponding to the vertical direction of the bottle.

The expanded polystyrene sheet 3 is die-cut in a shape that matches the unprinted transparent area intentionally provided on the non-expanded polystyrene film 1, and the transparent area 4 is aligned with the die-cut area. Moreover, the expanded polystyrene sheet 3 and the non-expanded polystyrene film 1 are adhesively laminated with the flow direction aligned using the printed surface (portion) 2 of ink having adhesive properties.

The adhesive ink referred to in the present invention is, for example,
Examples include printing inks containing at least 20% or more of the total solid content of a polymethacrylic acid ester binder.

The two-layer structure of a foamed polystyrene sheet and a non-foamed polystyrene film is because the foamed polystyrene sheet alone is made by cutting out a sleeve with slits in the longitudinal direction of the bottle, that is, in the direction perpendicular to the flow direction of the foamed polystyrene sheet. This is to prevent the die-cut slit from deforming due to the shrinkage force generated in the flow direction of the foamed polystyrene sheet when heating it, or to prevent the sleeve from tearing or twisting due to cracking from the die-cut part. This is to alleviate the concave feeling caused by punching out the polystyrene foam sheet, and to prevent dust from accumulating in the concave portions.

〔Example〕

Polystyrene resin Product name Dialex HH102 95 parts by weight (manufactured by Mitsubishi Monsanto) HI polystyrene resin Product name Tuffprene (manufactured by Asahi Kasei) 5 parts by weight Foaming agent n-pentane (manufactured by Gordo Solvent) 5 parts by weight were injected into a foaming extruder. The thickness is 0.3 mm, the expansion ratio is 7 times, and the shrinkage is 75% (140℃) in the flow direction coming out of the extruder, but only 15% (140℃) in the direction perpendicular to the flow. Do not create expanded polystyrene sheets. A slit mold was cut out in a direction perpendicular to the flow of the foamed polystyrene sheet, and a slit mold provided on the foamed polystyrene sheet was placed on the back side of a non-foamed polystyrene film having a thickness of 25μ and having the same heat shrinkability as the foamed polystyrene sheet. A transparent part that is not printed is provided in the direction perpendicular to the flow of the non-foamed polystyrene film so as to match the part cut out, and the remainder is filled with polymethyl methacrylate and polybutal methacrylate (1:1 mixture). A floral pattern is printed using gravure ink containing 60% solid content.
A shrinkable composite sheet for forming a sleeve having a viewing window was produced by thermocompression bonding to the expanded polystyrene sheet with the windows and flow direction aligned. Then, both ends of this shrinkable composite sheet for forming a sleeve having a viewing window are pasted together into a cylindrical shape corresponding to the diameter of the glass bottle.
A glass bottle that is wrapped around a glass bottle and then shrunk with hot air is more susceptible to deformation of the window and parts of the window after shrinking than a glass bottle that is made by cutting slits into a single-layer polystyrene foam sheet. There was no cracking or tearing of the sleeve, and a clean viewing window was formed.

[Effect of idea]

Since the shrinkable composite sheet for forming a sleeve with a viewing window according to the present invention having the above-mentioned structure has a two-layer structure of a non-expanded polystyrene film and an expanded polystyrene sheet, it can be cut into a single expanded polystyrene sheet. Compared to sheets with a viewing window, there is no possibility of deformation of the window after shrinkage, cracks from the window, and tearing of the sleeve. This makes it easy to install a viewing window for viewing the interior.

[Brief explanation of drawings]

Fig. 1 is a perspective view showing the state of the shrinkable composite sheet for forming a sleeve having a viewing window according to the present invention after shrinking it into a bottle, and Fig. 2 shows the structure of the sheet at the die-cut portion in Fig. 1. FIG. 1... Non-expanded polystyrene film, 2... Printed area with adhesive ink, 3... Expanded polystyrene sheet, 4... Transparent area that is not printed.

Claims (1)

[Claims for Utility Model Registration] 1. A printed surface of a heat-shrinkable non-foamed polystyrene film having a transparent portion without printing, and a heat-shrinkable foamed polystyrene sheet having a die-cut portion. A shrinkable composite material for forming a sleeve having a viewing window through which the contents of a glass bottle or the like can be viewed, characterized in that the transparent part and the die-cut part are aligned and bonded together using printing ink having adhesive properties. sheet. 2. A non-expanded polystyrene film with a thickness of 20 to 40μ, a heat shrinkage rate of 60 to 80% (140℃) in the direction of flow during production, and a heat shrinkage rate of 10 to 30% (140℃) in the direction perpendicular to the flow; A utility model consisting of an expanded polystyrene sheet with a thickness of 0.2 to 0.4 mm, a heat shrinkage rate of 60 to 80% (140℃) in the flow direction, and a heat shrinkage rate of 10 to 30% (140℃) in the direction perpendicular to the flow direction; A shrinkable composite sheet for forming a sleeve having a viewing window according to claim 1.