JP2615303B2 - Heat shrinkable 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 label which is wound around the entire periphery of a container.

[0002]

2. Description of the Related Art Conventionally, a polyvinyl chloride resin or a polystyrene resin is mainly used for a heat-shrinkable plastic film or sheet used as a one-way container, particularly a label wound around a glass bottle. However, harmful gases generated during incineration of polyvinyl chloride resins are problematic. Further, a foamed sheet or a non-foamed film processed from a polystyrene-based resin has low impact resistance, and is restricted in a range of use. Further, the film or sheet made of each material has problems such as dimensional change and whitening of the label at a temperature exceeding 90 ° C., and its use is limited. On the other hand, labels made of polypropylene resin have also been developed, but although the heat resistance is superior to the above-mentioned resins,
There is also a problem that the heat shrinkage is weak, the production speed is low, and the washing water or the filled liquid is not adhered to the glass bottle and enters between the container and the label. Further, it is difficult to attach a label made of a polypropylene resin with a solvent, and it is not suitable for a labeler of a system in which the end faces of the label are overlapped and wound around with a solvent.

[0003]

DISCLOSURE OF THE INVENTION The present invention has been made to solve the above-mentioned problems, and an object of the present invention is to have heat resistance enough to withstand retort aptitude and impact resistance. It is an object of the present invention to provide a label which is excellent in heat shrinkability and excellent in heat shrinkability, and can be wound not only by heat sealing but also by overlapping the end faces of the label with a solvent.

[0004]

Means for Solving the Problems Under the aforementioned circumstances, the present inventors have conducted intensive studies on a label wound around a crowsbin and found that a label obtained by laminating a polyester film on both sides of a polyolefin film is effective. ,
The present invention has been completed. That is, the above object of the present invention is achieved by using a polyolefin-based film and a polyester film having a specific heat shrinkage.

Hereinafter, the present invention will be described in detail. The polyolefin film referred to in the present invention is polyethylene, polypropylene, ethylene-vinyl acetate resin, ethylene-
It is a resin selected from resins such as propylene copolymer resin, preferably a resin mainly composed of polypropylene, and the thickness of the film used is 0.01 to 0.30 mm.
Is preferred. Further, the film may be a foamed film or a non-foamed film, but is preferably a foamed film having a thickness of 0.05 to 0.3 mm. When the thickness is less than 0.01 mm, the impact resistance is insufficient, and the loss is large even in the printing process. Conversely, if it exceeds 0.30 mm, the polyester film is laminated and rolled up into a roll, and while being cured, the film is curled, resulting in a large loss in the step of winding around the container. In addition, efficiency during heat treatment such as retort sterilization is reduced, and slip on a line is deteriorated, which is practically undesirable. Further, the density of the foamed polyolefin film is preferably 0.1 to 0.8 g / cm ² .

Further, this film has a heat shrinkage in one direction at 150 ° C. of not less than 20%, preferably 30%.
Der least% is, the thermal shrinkage in this direction 90 ° direction 5
Ru less than% der. Further, it is preferable that the difference from the heat shrinkage in one direction of the polyester film is within 40% in the same laminating direction. If the heat shrinkage in one direction at 150 ° C. is less than 20%, the shrinkable label is restricted or the label winding speed is reduced. The film is preferably subjected to corona treatment on both front and back surfaces.

The polyester film referred to in the present invention is:
It consists of a glycol-modified polyester copolymer.
The glycol-modified polyester copolymer is preferably soluble in an organic solvent such as tetrahydrofuran or methylene chloride. The thickness is 0.005
It is 0.05 mm. If the thickness is less than 0.005mm,
Wrinkles and the like occur in the printing or laminating process, resulting in a large loss or insufficient sealing strength when a solvent or heat sealing is performed. Conversely, if the thickness exceeds 0.05 mm, the laminate will be rolled and then curled while being rolled and cured, resulting in a loss when the label is wound around a container.

Further, shrinkage at 0.99 ° C. of the polyester film, it is in large contraction in the same direction as that of the polyolefin film 20% or more, preferably Ri der 30% or more, in the direction of 90 ° direction Heat shrinkage
There Ru less than 5% der. If the heat shrinkage in one direction is less than 20%, there is a restriction as a shrinkable label and the winding speed of the label decreases. This film is preferably subjected to a corona treatment on the laminated surface. Printing is performed on the boundary surface between the polyolefin-based film and the polyester film, and printing may be performed on the polyolefin-based film or on the polyester film. Preferably, it is a polyolefin-based film.

The adhesive applied to the interface between the polyolefin-based film and the polyester film is preferably a polyurethane-based adhesive. The polyurethane adhesive is 1
An adhesive obtained by reacting a normal polyisocyanate having two or more isocyanate groups per molecule with a polyether or polyester having hydroxyl groups at both ends, for example, Adcode AD (trade name, manufactured by Toyo Morton Co., Ltd.), Olester NP trademark -1100 / NL-2488 (manufactured by Mitsui Toatsu Chemicals, Inc.). To apply the polyurethane adhesive to the interface between the polyolefin film and the polyester film, a normal dry lamination apparatus can be used, and even if the polyester film is laminated on both sides of the polyolefin film at one time, There is no problem even if they are laminated one by one. The curing of the adhesive is preferably performed at a temperature of 50 ° C. or less for a few days. The amount of the polyurethane adhesive applied is 0.5 to 5 g /
A range of m ² is preferred. The laminated film of the wide polyolefin-based film and the polyester film printed in this manner is cut into a desired width for one row and then wound up. The printing film continuously repeated in one line is cut at a predetermined position on each of the machines to be wound around the label container to form a label, and at the same time, the leading end of the label is tightly wound on the container without slipping. On the other hand, a solvent is applied to the rear end portion of the label, and this portion is overlapped with the front end portion of the label and wound around the body of the container. If necessary, heat is applied to the label and the label is brought into close contact with the glass bottle.

[0010]

Next, the present invention will be described with reference to typical examples. Example 1 [Polyolefin-based film] A polypropylene and low-density polyethylene were used as main raw materials, and azodicarboxylic amide was used as a foaming agent. The thickness is 0.12 mm and the density is 0.
The shrinkage at 150 ° C. at 6 g / cm ³ is ³ in the machine direction (MD).
5% foamed polyolefin film at 2% perpendicular (TD). This film was subjected to corona treatment on both sides and printed on one side. [Polyester film] A polyester film synthesized from terephthalic acid and a diol. The modified polyester containing cyclohexyldimethanol in the diol was used as a raw material, and after extruding the film with an extruder, the film was stretched in the machine direction (MD) with a roll stretching machine. A film with a thickness of 0.03m
m, a film whose shrinkage at 150 ° C. is 50% in MD and 5% in TD.

The above-mentioned polyolefin-based film and polyester film were bonded with a two-pack type polyurethane-based adhesive (Ad Code; manufactured by Toyo Morton) to obtain a three-layer laminated film. The heat shrinkage of this film was (immersed in an oil bath at 150 ° C. for 3 minutes) and the MD was 45
% And TD were 4%. This laminated film has a width of 100
After slitting into a ring shape of mm, it was cut into a length of 220 mm to obtain a label. The label was wound along a glass bottle having a body portion of 67 mmφ and a shoulder portion of 40 mmφ, and the joined portion was adhered with tetrahydrofuran (THF) to form a cylindrical body.
(Sleeve moldability) Thereafter, the label was heated together with the glass bottle to make it adhere to the bottle. The label did not delaminate even when heated, and had a beautiful appearance after shrinkage (shrink performance). These coated glass bottles were left in hot water at 120 ° C. for 30 minutes, but the appearance was almost the same as before the treatment (retort resistance).

Comparative Examples 1-2 The shrinkage ratios of the polyester films were measured using MD32
%, TD 14%; MD 15%, TD 4%, except that the same laminated label was produced as in Example 1, and the sleeve moldability and shrink performance were examined. Comparative Examples 3 and 4 Shrinkage MD18% of foamed polyolefin film, TD
A label was prepared and evaluated in the same manner as in Example 1 except that the MD was 4%; the MD was 32%, and the TD was 15%. The results are shown in Table 1.

Example 2 A polyolefin film was a non-foamed film having a thickness of 0.03 mm and a heat shrinkage of 150% at 25 ° C. and a MD of 25%.
Except for 3%, a laminated label was prepared and evaluated in the same manner as in Example 1. A product with an excellent appearance and a refreshing feeling was obtained.

Comparative Example 5 Polyester film thickness and shrinkage were 0.004 m
A label was prepared and evaluated in the same manner as in Example 1 except that m, MD 58% and TD 2%. Although sealed with a solvent, about half of the glass bottles discharged from the labeler peeled off the sealed part.

Comparative Example 6 A polystyrene film having a thickness of 0.05 mm was used instead of the polyolefin film, and the shrinkage was MD 78% and TD 0%.
A label was prepared and evaluated in the same manner except that the polyolefin-based film was used. Although the sleeve moldability and shrink performance were good, the label was deformed and peeled off when the retort test was performed.

[0016]

[Table 1]

[0017]

According to the heat-shrinkable label of the present invention, when the sleeve-shaped composite film is heated and shrunk, there is no wrinkle due to shrinkage, and a composite film suitable for a pre-label which does not loosen after shrinkage. can get. With this composite film, even in a high-temperature heat treatment step such as retort sterilization, the printing ink does not directly rub against each other, and the problems of ink dropout and ink transfer are eliminated. In addition, not only a heat seal type machine but also a solvent seal type machine can be wound around a glass and a bottle, and the range of choice of a label machine has been widened. When a foamed film is used as the polyolefin film, not only are the sealing conditions wide and stable when forming the sleeve, but the rigidity is improved due to the thickness of the foamed polyolefin film, and the loss due to bending when the sleeve is mounted on the container. Has an effect on production, such as a decrease in

Continuation of the front page (51) Int.Cl. ⁶ Identification number Agency reference number FI Technical indication location C09J 7/02 JJA C09J 7/02 JJA // B29K 105: 02 B29L 22:00

Claims (1)

(57) [Claims] 1. A label wrapped around the entire outer periphery of a container, having a thickness of 0.01 to 0.30 mm and a shrinkable property.
At a temperature of 150 ° C, the height is 20% or more in the circumferential direction of the container.
Less than 5% of the polyolefin-based film in both directions ,
The thickness is 0.005-0.05mm and the shrinkage performance is 150
At a temperature of ℃, 20% or more in the circumferential direction of the container, 5% in the height direction
A heat-shrinkable label comprising a laminate of a glycol-modified polyester film soluble in less than an organic solvent and a printed surface at the boundary surface.