JP3455395B2 - Tubular shrink label - Google Patents

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a cylindrical shrink label attached to a synthetic resin container such as polyethylene terephthalate (hereinafter referred to as PET) which is a beverage container for soft drinks, coffee beverages, etc., or a glass bottle, and particularly to a container. The present invention relates to a cylindrical shrink label that can be easily attached.

[0002]

2. Description of the Related Art PET bottles, glass bottles, etc. used as containers for soft drinks, coffee beverages, etc., have a cylindrical shrink printed on their inner surfaces to display their trade names, trademarks, ingredients, designs, etc. A label is generally attached.

As described above, this type of tubular shrink label is formed by forming a heat-shrinkable film having a product name or the like printed on its inner surface into a tubular shape slightly larger than the outer diameter of the container. 80-9 after fitting into the filled container
By spraying steam at about 0 ° C. to shrink the heat-shrinkable film, the heat-shrinkable film is held in close contact with the container surface.

[0004]

By the way, there are many cases where water drops adhere to the surface of a container such as a PET bottle into which the above-mentioned cylindrical shrink label is inserted, in the manufacturing process of beverage products. If you try to insert a tubular shrink label that is slightly larger than the outer diameter of the container into a container with water droplets attached, the presence of the water droplet causes the tubular shrink label to adhere to the container surface, resulting in a tubular shrink label. However, there is a problem in that it cannot be smoothly inserted into a predetermined position of a container such as a PET bottle.

Particularly in recent years, when the demand for beverage products filled in PET bottles and the like has increased, the mounting speed of labels on containers has become one of the factors that influence the productivity of beverage products. It is desired that the tubular shrink label can be fitted into a container such as a PET bottle as smoothly as possible.

On the other hand, the above-mentioned problems can be solved to some extent by increasing the thickness of the tubular shrink label itself to increase the rigidity of the label or by increasing the inner size of the tubular shrink label. However, if the thickness and the inner size are increased, there is a problem that the material cost of the label itself is increased and the product cost is increased.

Therefore, an object of the present invention is to provide a tubular shrink label which can be smoothly inserted into a container such as a bottle whose surface is wet with water, while suppressing the material cost.

[0008]

In order to solve the above-mentioned problems, the tubular shrink label of the present invention has improved water repellency of the inner surface by suppressing the wetting index of the inner surface to 34 or less. .

The term "wetting index" as used herein means a mixture of liquids which are determined to be wetted by applying a series of mixed liquids having different surface tensions to the inner surface of the shrink label. It is a numerical value of surface tension (dyn / cm), and is measured by the same method as the wetting test method for polyethylene and polypropylene films (JIS K 6768).

In order to solve the above problems, the tubular shrink label of the present invention suppresses the dynamic friction coefficient of the inner surface of the polyester surface in the water wet state to 0.6 or less with respect to the polyester surface in the water wet state . The slip property of the inner surface of the label with respect to the surface of the polyester which is wet with water is improved.

The term "coefficient of dynamic friction in water wet state " as used herein means a polyester whose coefficient of dynamic friction between the same materials is 0.45, which is measured by a friction coefficient test method for plastic films and sheets (JIS K 7125). Using the sheet as a mating material, with 0.1 ml of water droplets dropped on the surface of the polyester sheet, a test piece is superposed on the surface of the polyester sheet, the test speed is 500 mm / min, the friction distance is 150 mm,
It is a value measured by the method according to JIS K 7125 described above.

The inner surface of the tubular shrink label is usually
Since it is composed of the surface of the white printing layer that is gravure-printed with white ink, the wetting index of the surface of the white printing layer is 34 or less, or the coefficient of kinetic friction of the surface of the printing layer in the water wet state is 0.6 or less. It is desirable to set.

[0013]

BEST MODE FOR CARRYING OUT THE INVENTION Embodiments will be described below with reference to the drawings. This tubular shrink label is attached to a rectangular PET bottle after being formed into a tubular shape and then folded flat and then opened by folding it into a substantially rectangular tubular shape as shown in FIG. It is configured to be.

As shown in FIG. 2, this cylindrical shrink label 1 is formed of a polyester resin such as PET, a polystyrene resin such as polyvinyl chloride, a styrene-butadiene copolymer, or the like in the lateral direction (circumferential direction). ) A film base material 11 having a thickness of 20 to 80 μm that shrinks by 30%
And a display print layer 12 formed on the inner surface of the film substrate 11 for displaying a trade name, a trademark, a component, various designs, and the like, and a white print layer 13 formed on substantially the entire surface of the display print layer 12. The display printing layer 12 is composed of
The white print layer 13 is formed by gravure printing.

The white ink for forming the white printing layer 13 includes a solvent such as esters such as ethyl acetate, aromatic hydrocarbons, various alcohols and ketones, a binder such as an acrylic resin, and a surface. It contains a pigment such as titanium oxide which is hardly treated, and various additives, and has a wettability index of 34 or less on the printing surface and a dynamic friction coefficient of 0.6 or less in a water wet state. .

As the additive, silica fine powder is usually used in order to prevent blocking of the printing surface. The white ink used this time contains silica fine powder in order to suppress water absorption. Uses almost no liquid and uses liquid silicone.

Examples of the present invention will be described below, but the present invention is not limited to these examples.

(Examples 1 to 3 and Comparative Examples 1 to 4) A display printing layer was formed on the inner surface of a heat-shrinkable film made of PET, and white was formed on the entire surface of the display printing layer with a white ink. The film thickness of the label base material on which the print layer was formed, the wetting index of the surface of the white print layer, and the coefficient of dynamic friction in the water wet state were adjusted to the values shown in Table 1, respectively. The values of the wettability index and the coefficient of kinetic friction in a water wet state are contained in the white ink to be used, the kind of liquid silicone used as a pigment or an additive such as titanium oxide which is hardly surface-treated, and It was adjusted by changing the content.

Then, using each label substrate,
Square PET bottle with a capacity of 900 ml (outer circumference: 255
mm) to form a square tube-shaped shrink label (inner peripheral size: 264 mm), and fold it flat to raise it into a square tube, and set the mounting speed to 150 BPM (number of mounted bottles / minute) and 220 BPM. The mounting workability when mounted on the square PET bottle was evaluated (see Table 1).

[0020]

[Table 1]

As can be seen from Table 1, the film thickness is 4
Regarding Example 4 in which the printing surface has a wetting index of 5 μm and the white printing layer is 34, the wetting index of the white printing layer is 34 or less, although the mounting workability is slightly lowered when the mounting speed is 220 BPM. In Examples 1 to 4 in which the dynamic friction coefficient in the water-wetted state was adjusted to 0.6 or less, generally good mounting workability was obtained at both the mounting speeds of 220 BPM and 150 BPM.

On the other hand, in Comparative Examples 1 to 3 in which the wetting index of the printing surface of the white printing layer was adjusted to 36 or more and the dynamic friction coefficient in the water wet state was adjusted to 0.71 or more, the mounting speed was 150 B.
It can be seen that when PM is used, good mounting workability is generally obtained, but when the mounting speed is increased to 220 BPM, mounting workability is generally deteriorated. Comparative Example 1 is a conventionally used tubular shrink label.

As described above, if the wetting index of the inner surface of the tubular shrink label is set to 34 or less and the dynamic friction coefficient in the water wet state is set to 0.6 or less, the mounting speed to the bottle can be increased to about 220 BPM. Also, good mounting workability can be obtained, and the film thickness can be reduced to about 45 μm.

Therefore, in order to improve the mounting efficiency of the label, it is not necessary to increase the inner peripheral dimension of the shrink label with respect to the outer peripheral dimension of the container such as a bottle, and the material cost of the label itself is lower than the conventional one. It is possible to improve productivity of beverage products and the like while suppressing.

Incidentally, in the above-mentioned embodiment, the rectangular PE
Although the shrink label to be attached to the T bottle by opening it in a substantially rectangular tube shape from the folded state has been described, the same effect can be obtained with a cylindrical shrink label attached to a round or polygonal polyester bottle or the like. Needless to say, it can be obtained. Further, the same effect can be obtained in a water-wetting container such as a plastic container other than polyester or a glass bottle.

Further, in the above-described embodiment, the wetting index of the surface of the white printing layer 13 which is the inner surface is 34 or less, and
Although the dynamic friction coefficient in the water-wetted state is set to 0.6 or less, the inner surface does not necessarily have to be the white printed layer, and either the wetting index or the dynamic friction coefficient in the water-wet state is within the above range. I hope However, since a white printing layer is generally provided on the innermost surface of this type of shrink label, the wetting index of this white printing layer or the coefficient of kinetic friction in a water wet state is set within the above range. It is preferable to set.

Further, the display printing layer 12 and the white printing layer 13 are preferably formed by gravure printing in consideration of printability on a film substrate, but other coating methods such as flexographic printing are used. You can also

[0028]

As described above, in the tubular shrink label of the present invention, the wetting index of the inner surface is suppressed to 34 or less to enhance the water repellency of the inner surface or to the polyester surface which is wet with water. The thickness of the label itself is reduced by adopting a structure that improves the slipperiness of the inner surface of the label with respect to the polyester surface in the water wet state by suppressing the dynamic friction coefficient of the water surface in the water wet state to 0.6 or less. It can be smoothly inserted into a container with water droplets without increasing the inner size.

As a result, it is possible to improve the productivity while suppressing the product cost of beverage products and the like.

[Brief description of drawings]

FIG. 1 is a perspective view showing an embodiment according to the present invention.

FIG. 2 is a sectional view of the same.

[Explanation of symbols] 1 Cylindrical shrink label 11 Film substrate 12 Display printing layer 13 White printing layer

─────────────────────────────────────────────────── ─── Continuation of the front page (58) Fields surveyed (Int.Cl. ⁷ , DB name) G09F 3/04 B32B 7/02 106

Claims (3)

(57) [Claims] 1. A tubular shrink label having a wetting index of 34 or less on the inner surface. 2. A tubular shrink label having a coefficient of kinetic friction of the inner surface of the polyester surface which is wet with water in a water wet state of 0.6 or less. 3. The cylindrical shrink label according to claim 1, wherein the inner surface is formed of a white printed layer obtained by gravure printing white ink.