JP2000301632A - Tubular material and stretchable label - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a tubular material and a stretchable label which have sufficient center sealing strength due to adhesion by laser irradiation and can be manufactured with high production efficiency. SOLUTION: This tubular material is formed of a cylindrically formed film 3 by overlapping both end parts 3a, 3b of a synthetic resin film 3 and bonding the parts by laser irradiation. The film 3 has an intermediate layer 1 and a surface layer 2 laminated on both face sides of the intermediate layer 1, which is formed of a material with higher laser absorbing properties than the surface layer 2.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a tubular tube and a stretch label which are externally fitted to a container such as a beverage or a detergent, and more particularly to a tube and a stretch label having both ends adhered by a laser. About.

[0002]

2. Description of the Related Art Heretofore, as this kind of tube body, for example, a tube body in which both ends of a self-stretchable polyethylene film are bonded to each other with an adhesive such as a urethane adhesive is known.

[0003] The tube body is cut to a desired length,
It is used by forming it into a tubular stretch label or the like. And this stretch label is expanded by external force,
After being externally fitted to the container or the like, the outer diameter is reduced (substantially restored to the original shape) by removing external force, and the container is closely attached to the container or the like by the elastic contraction force (externally fitted).

However, the above-mentioned conventional tube body has
The adhesive strength between the films (hereinafter, referred to as "center seal strength") becomes unstable due to uneven application of the adhesive, so that the adhesive strength of the film is improved (the wettability of the adhesive is improved). It was necessary to perform a corona discharge treatment on the bonded portion. Further, in order to cure (cure) the adhesive, after bonding both ends of the film, the film is placed in an aging room kept at about 25 to 40 ° C. for a long time (about 24 to 48 hours). ) Had to stand still.

Therefore, not only does it take a long time to manufacture, but also the bonding condition of the tube body cannot be inspected immediately and the bonding defect cannot be found at an early stage. Therefore, the bonding defect is found after curing, and the production must be restarted from the beginning. Some things had to happen. Another problem is that it is necessary to secure a place for installing the aging room.

[0006] In order to solve such a problem, the present inventors have studied a method of securely bonding both ends of the film by laser irradiation in a short time.

[0007]

However, current films such as polyethylene films cannot efficiently absorb laser light and cannot obtain sufficient heat for bonding. The strength was insufficient, and it took a long time to bond the films (irradiation with laser), resulting in poor production efficiency.

The present invention has been made in view of the above problems, and an object of the present invention is to provide a tube body and a stretch label which have sufficient center seal strength by adhesion by laser irradiation and can be manufactured with high production efficiency. And

[0009]

In order to solve the above problems,
The tube according to the present invention is a synthetic resin film 3.
The film 3 is formed into a tubular shape by superposing the two end portions 3a and 3b of each other and bonding them by laser irradiation. In this case, the film 3 is composed of an intermediate layer 1 and both surfaces of the intermediate layer 1. And a surface layer 2 laminated on the side, wherein the intermediate layer 1 is formed of a material having a higher laser absorption than the surface layer 2.

In the tube having the above structure,
When the both ends 3a and 3b of the overlapping films are adhered to each other by laser irradiation, the intermediate layer 1 of the film is made of a material having a higher laser absorption than the surface layer 2, so that the same laser as the surface layer 2 is used. As compared with the case where a material having absorptivity is used for the intermediate layer 1, the film absorbs the laser more efficiently and obtains sufficient heat (fusion heat or softening heat) for bonding. In addition, since the heat generated in the intermediate layer 1 by the absorption of the laser is conducted to the surface layers 2 on both sides, the surface layers 2 on both sides obtain heat in a well-balanced manner.

When a carbon dioxide laser is used as the laser, the intermediate layer 1 is made of a polyethylene resin to which a carbon dioxide laser absorbent is added, and the film is made of a carbon dioxide laser. 10 to 6
Those that absorb 0% are preferred. If it is 10% or more, the film absorbs the laser more efficiently and obtains sufficient heat for bonding, so that a tube body having more excellent center seal strength and production efficiency can be obtained. Also, 60
% Or less, a tube body with little decrease in the strength of the film itself is obtained. That is, if the absorption rate is larger than 60%, depending on the intensity of the laser, the film may be heated more than necessary in a short time, and the film itself may be damaged, causing a decrease in strength. By doing so, such a situation can be prevented, and since the laser absorber is not added unnecessarily, a tube body in which the strength of the film itself is small and the decrease in transparency is also prevented is obtained.

The wavelength of the carbon dioxide laser is about 10.6.
Since it is μm, the value of the absorptance (10 to 60%) of the carbon dioxide laser shown here is the value of the absorptivity of the infrared ray (wavelength 10.6 μm) measured by the infrared spectrophotometer.

Here, examples of the carbon dioxide laser absorber include fine particles of aluminosilicate, silica fine powder, kaolin diatomaceous earth, epoxy resin, polymethyl methacrylate, and the like. Above all, aluminosilicate is preferable. When aluminosilicate is used, the addition amount is 1 to 10% by weight, preferably 3 to 6% by weight based on the polyethylene resin, and a carbon dioxide laser is used for the entire film. Those absorbing 60% are preferred.

Aluminosilicate can be obtained from naturally occurring zeolites (zeolites), artificial zeolites and the like, and the aluminosilicate may be added by adding the zeolite as it is. In this case, the zeolite to be added preferably has a particle size of 0.5 to 6 μm. The zeolite having such a particle size absorbs the carbon dioxide laser more efficiently.

Examples of the polyethylene resin include low density polyethylene (LDPE), linear low density polyethylene (L-LDPE), metallocene polyethylene, ethylene vinyl acetate copolymer, ethylene acrylic acid copolymer, ethylene propylene. Examples thereof include copolymers and the like and mixtures thereof.

In the tube body of the present invention, claim 3
As described above, it is preferable that the surface layer 2 is free of a carbon dioxide laser absorber. By making the surface layer 2 without carbon dioxide laser added, it is possible to prevent the carbon dioxide laser absorbent particles from being exposed on the film surface, and to prevent the printability of the film from being deteriorated and the film from being easily cut. it can. Moreover, the intermediate layer 1 and the surface layer 2
The haze (cloudiness) of the film as a whole can be reduced as compared with a case where a carbon dioxide gas absorbent is uniformly added to the film, and a film having excellent transparency can be obtained.

Further, in order to solve the above-mentioned problem, the tube body according to the fourth aspect is characterized in that both ends 3a,
3b are overlapped and bonded by laser irradiation, so that the film is formed into a tubular body, and the film includes at least a polyethylene resin, and the polyethylene resin includes an aluminosilicate. Is added, so that the carbon dioxide gas laser absorptivity of the entire film is set to 10 to 60%.

In the tube having the above structure,
The aluminosilicate is added to the polyethylene resin, and the absorption rate of the carbon dioxide gas laser as the whole film is 10% or more, so that the film efficiently absorbs the laser and obtains sufficient heat for bonding. Become
By setting the content to 60% or less, the film is prevented from being heated more than necessary and damaged, and the strength of the film itself is hardly reduced. Therefore, a tube body having sufficient center seal strength and film strength and capable of being manufactured efficiently can be obtained.

In the stretch label according to the present invention, both ends 3a and 3b of a synthetic resin film 3 on which printing 4 has been performed are overlapped and adhered by irradiation with a carbon dioxide gas laser so that the film 3 is formed. In the stretch label formed in a tubular shape, the film 3
Is provided with an intermediate layer 1 made of a polyethylene resin to which aluminosilicate is added, and a surface layer 2 made of a polyethylene resin laminated on both sides of the intermediate layer 1 and having an absorptance of a carbon dioxide gas laser of 10 to 10. It is characterized in that the printing 4 is performed on one side, and the one side is inside, and is formed in a cylindrical shape.

In the stretch label having the above structure, as described above, the film absorbs the laser efficiently by the aluminosilicate, and generates sufficient heat for bonding.
The surface layers 2 on both sides are obtained with good balance. Furthermore,
Since the carbon dioxide laser absorption of the film is 10 to 60%, the stretch label has sufficient center seal strength and film strength, and can be manufactured efficiently. Furthermore, since the surface layer 2 is made of a polyethylene resin to which no aluminosilicate is added or to which a smaller amount is added than that of the intermediate layer 1, the entire film is compared with the case where the aluminosilicate is uniformly added to the intermediate layer 1 and the surface layer 2. As a result, an increase in haze can be prevented, and a film having good transparency can be obtained. Therefore, by forming a cylindrical shape with one side on which the print 4 is applied inside, the print 4 is covered with the film.
Thus, the stretch label can be prevented from being damaged, and the print 4 can be recognized from the outside.

[0021]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS Hereinafter, embodiments of a tube (stretch label) of the present invention will be described with reference to the drawings.

As shown in FIG. 1, the tube body of the present embodiment has an intermediate layer 1 and a surface layer 2 having a thickness of 2 to 10 μm laminated on both sides of the intermediate layer 1. A polyethylene film 3 is formed in a cylindrical shape as shown in FIG. 2, and both overlapping end portions (including the vicinity of the edge) 3a and 3b are adhered to each other by irradiation with a carbon dioxide gas laser.

On one side of the film 3, except for a non-printed portion 4a at one end 3a, a printed 4
The surface layer 2 is exposed in the non-printed portion 4a.

On the other side of the film 3, the surface layer 2 is exposed without being subjected to the printing 4, so that the film 3 is positioned such that one side having the printing 4 is on the inside. When formed into a tubular shape and overlapped with the other end 3b such that one end 3a is on the outside, the portion of the end 3b that contacts the non-printed portion 4a is Be done.

The intermediate layer 1 is made of low-density polyethylene (melting point: 125 ° C.) to which zeolite (aluminosilicate content: about 100% by weight) is added in an amount of 3 to 6% by weight (based on the whole resin after addition). The surface layer 2 is made of a linear low-density polyethylene (melting point: 102 ° C.) to which no zeolite polymerized by using a metallocene catalyst is added (hereinafter, referred to as “metallocene polyethylene”). The melting point is obtained by measuring the peak temperature at the time of raising the temperature with a suggestive calorimeter (measured according to JIS K7122).

Further, by the addition of zeolite, the polyethylene constituting the intermediate layer 1 is made to be a material having a higher laser absorption than the polyethylene constituting the surface layer 2, and the carbon dioxide gas of the film 3 as a whole is The laser absorptivity is 10 to 60% (preferably 25 to 50%).
%).

As shown in FIG. 3, the film 3 having the above structure is formed in a tubular shape so that the print 4 is on the inside, and the end 3a having the non-printed portion 4a is on the outside, and The two end portions 3a and 3b are overlapped so that the two (non-printed portions 4a and 4b) are in contact with each other, and the surface layers 2 (non-printed portions 4a and 4b) are softened or melted by irradiation with a carbon dioxide gas laser. It is adhered and formed into a tube body.

Next, a description will be given of a method of manufacturing the tube body of the present embodiment having the above configuration. The film 3 formed on the tube body of the present embodiment guides the low-density polyethylene of the intermediate layer 1 and the metallocene-based polyethylene of the surface layer 2 in a molten state by separate extruders, and extrudes from one die. It is manufactured by a co-extrusion method of laminating. When the film 3 is formed by such a co-extrusion method, the layers are adhered to each other in a molten state, so that the characteristics of each layer are not lost.

The printing 4 is performed by a known method such as a gravure printing method.

Thereafter, as shown in FIG. 4, the long film 3 slit to a predetermined width is guided to the former 6, and
Feed out continuously. At this time, the film 3 is folded into a tubular shape by the former 6 and a bending jig (not shown) so that the print 4 is on the inside. Both ends 3a and 3b of the film 3 folded into a cylindrical shape are overlapped so that the end 3a is located outside at the upper center of the former 6, and the non-printed portions 4a and 4b (surface layers 2) are in contact with each other. Then, a laser beam is irradiated from above by the carbon dioxide laser irradiation device 7, and both ends 3a and 3b are sequentially bonded to form a tube.

The tube of the present embodiment can be manufactured as described above by the above configuration, and has the following advantages.

That is, in the present embodiment, the carbon dioxide laser absorptivity of the whole film is set to 10 to 60%, so that when the both ends 3a and 3b of the film 3 are overlapped, Even if the laser is irradiated from the end 3a), the end 3
In this case, it is possible to prevent a situation in which the laser beam is almost absorbed by a and the inner end portion 3b cannot obtain sufficient heat, and both end portions can be securely bonded. Moreover, the laser absorption rate is 25
In the range of ~ 50%, the laser can be efficiently absorbed, and the difference in the amount of laser absorption between the inner end 3a and the outer end 3b can be reduced. Since both the portions 3a and 3b are melted or softened in a well-balanced manner, a tube body having excellent center seal strength is obtained.

Also, in order to reliably melt or soften and obtain a sufficient center seal strength, even if a relatively strong laser is used, the absorption rate is 60% or less, so that melting or softening is easily controlled. Inadvertent cutting of the film 3 can be prevented, and a tube body can be obtained in which the center seal strength and the film strength can be stably obtained with high production efficiency.

Further, in the present embodiment, since the resin constituting the surface layer 2 has a lower melting point than that of the intermediate layer 1, the surface layer 2 can be melted and softened preferentially over the intermediate layer 1. In addition, the surface layers 2 can be welded to each other without damaging the intermediate layer 1, and a tube body with less decrease in film strength can be obtained.

The tube manufactured by the above-described method is then cut into predetermined dimensions as shown in FIG. 5, formed into a stretch label 8, expanded in diameter, externally fitted to a container 9, and self-shrinked. It is closely attached to the container 9 depending on the nature.

At this time, the stretch label 8 has a strong center seal strength because the surface layers 2 at both ends 3a and 3b of the film are securely bonded to each other, and therefore, there is no possibility that the bonded portion is peeled off.

It should be noted that the present invention is not limited to the configuration of the present embodiment, and the design can be changed as appropriate.

That is, the resin constituting the intermediate layer 1 and the surface layer 2 is not limited to the above-mentioned polyethylene resin, but may be another resin such as a polypropylene resin.

In this embodiment, the case where the tube body is formed by using the self-stretchable film 3 and the tube body is formed as the stretch label 8 has been described. However, the tube body is formed by using the heat-shrinkable film. Even when the tube body is used as a shrink label, it is within the range intended by the present invention.

Furthermore, known additives such as a stabilizer, an antioxidant, a lubricant and an antiblocking agent can be appropriately added to the resin forming the intermediate layer 1 and the surface layer 2.

The thickness of each layer (intermediate layer 1, surface layer 2) and print 4 is not particularly limited.

Further, in this embodiment, the film 3 having a three-layer structure of the intermediate layer 1 and the surface layers 2 on both sides of the intermediate layer 1 is formed by the co-extrusion method. The present invention is not limited to this, and a dry laminating method in which a single-layer film for each layer separately formed is bonded to each other, an extrusion laminating method in which the surface layer 2 is melt-extruded on both sides of the intermediate layer 1, and the like. It may be manufactured by a known technique. The configuration is not limited to three layers, but may be one layer, two layers, or four or more layers.

[0043]

Embodiments will be described below. Example 1 An 80 μm thick middle layer made of low density polyethylene to which 4% by weight of zeolite (aluminosilicate content: about 100% by weight) was added, and a 5 μm thick metallocene polyethylene to which no zeolite was added on both surfaces. The film on which the surface layer was laminated was used as a test piece of Example 1. Example 2 The thickness of the intermediate layer was 70 μm, and the thickness of the surface layer was 10 μm.
A film having the same configuration as that of Example 1 was used as a test piece of Example 2 except that the above-mentioned was used. Example 3 A 90-μm-thick single-layer film made of low-density polyethylene to which 4% by weight of zeolite was added was used as a specimen of Example 3. Comparative Example A single-layer film having a thickness of 90 μm and comprising a resin in which low-density polyethylene was blended at 98.5% by weight and ethylene-vinyl acetate copolymer at 1.5% by weight was used as a specimen of the comparative example.

Measurement of laser absorptance and haze The carbon dioxide laser absorptivity and haze were measured using each of the specimens of Examples 1 to 3 and Comparative Example. The absorption of the carbon dioxide laser was measured by using an infrared spectrophotometer and measuring the absorption of infrared light having a wavelength of 10.6 μm. Table 1 shows the measurement results.

[Table 1] As is clear from Table 1, the carbon dioxide gas absorption rate of zeolite to which zeolite (aluminosilicate) was added (Examples 1 to 3) was significantly increased as compared with the case of not adding zeolite (aluminosilicate) (comparative example). It is understood that. Further, it is understood that those having a surface layer to which zeolite (aluminosilicate) is not added (Examples 1 and 2) have a small increase in haze relative to the rate of increase in carbon dioxide gas absorption.

[0045]

As described above, in the tube body according to the present invention, the film constituting the tube body efficiently absorbs the laser, and the surface layer obtains sufficient heat for adhesion in a well-balanced manner, so that the center layer has a sufficient center. It has the advantage that it has a sealing strength and can be manufactured with high production efficiency.

Further, in the stretch label according to the present invention, the film constituting the stretch label efficiently absorbs the laser, and the surface layer obtains sufficient heat for adhesion in a well-balanced manner, so that the center seal strength and the film have sufficient center seal strength. It is a stretch label that has strength and can be manufactured efficiently. Moreover, since the surface layer of the film is made of a polyethylene resin to which no aluminosilicate has been added or which has been added in a smaller amount than the intermediate layer, the film has good transparency, and is formed in a cylindrical shape with one side printed on the inside. By forming the stretch label, it is possible to prevent the print from being damaged, and to obtain a stretch label from which the print can be recognized from the outside.

[Brief description of the drawings]

FIG. 1 is a partially omitted sectional view showing first and second embodiments of the present invention.

FIG. 2 is a perspective view showing a use state of each embodiment.

FIG. 3 is a sectional view taken along line PP of FIG. 2;

FIG. 4 is a perspective view showing a manufacturing state of the first and second embodiments of the present invention.

FIG. 5 is a perspective view showing a use state of each embodiment.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 ... Middle layer 2 ... Surface layer 3 ... Film 3a, 3b ... Both ends 4 ... Printing

 ────────────────────────────────────────────────── ─── Continued on the front page F term (reference) 4F100 AC04B AK04A AK04B AK04C AK06 AR00A AR00B AR00C BA03 BA06 BA10A BA10C BA16 BA26 CA30B DA11 EJ52 GB90 HB31 JD14A JD14B JD14C JK06 JL02 JN01 YY00B

Claims (5)

[Claims] 1. A tube formed by laminating both ends (3a) and (3b) of a synthetic resin film (3) and bonding them by laser irradiation, whereby the film (3) is formed in a tubular shape. In the body, the film (3) includes an intermediate layer (1) and a surface layer (2) laminated on both sides of the intermediate layer (1), and the intermediate layer (1) A tube body formed of a material having a higher laser absorptivity than the surface layer (2). 2. The laser is a carbon dioxide laser,
The tube body according to claim 1, wherein the intermediate layer (1) is made of a polyethylene resin to which a carbon dioxide laser absorber is added, and the film absorbs 10 to 60% of the carbon dioxide laser. 3. The tube body according to claim 1, wherein the surface layer (2) is free of a carbon dioxide laser absorber. 4. A tube formed by laminating both ends (3a) and (3b) of a synthetic resin film (3) and bonding them by laser irradiation, whereby the film (3) is formed in a tubular shape. In the body, the film is
It comprises at least a polyethylene resin, and the aluminosilicate is added to the polyethylene resin,
The absorption rate of the carbon dioxide laser as the whole film is 10
A tube body characterized in that it is 〜60%. 5. Both ends (3a) and (3b) of a synthetic resin film (3) on which printing (4) has been performed are overlapped,
By bonding by carbon dioxide laser irradiation,
In the stretch label in which the film (3) is formed in a tubular shape, the film (3) includes an intermediate layer (1) made of a polyethylene-based resin to which aluminosilicate is added, and both surfaces of the intermediate layer (1). And a surface layer (2) made of a polyethylene resin to which no aluminosilicate is added or to which a smaller amount is added than the intermediate layer (1). The stretch label is characterized in that it is printed on one side and has a cylindrical shape with the one side inside.