JP2000141469A - Tube object and its production - Google Patents

Abstract

PROBLEM TO BE SOLVED: To obtain stabilized center seal strength with good production efficiency while ensuring the film strength of a bonded part when both overlapped end parts of the film are mutually bonded by laser beam in a tube object and a tube object producing method. SOLUTION: In a tube object obtained by overlapping both end parts 3a, 3b of a film 3 made of a synthetic resin to which printing is applied to bond them by the irradiation with laser beam to form the film 3 into a cylindrical shape, the film 3 is equipped with a base material 1 and the surface layers 2 laminated to both surfaces of the base material 1 and the surface layers 2 comprise a material having a melting point lower than that of the base material 1 and the bonding surfaces of both end parts 3a, 3b are formed to unprinted parts 4a, 4b to which printing is not applied.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a tubular body formed on a tubular label which is fitted to a container such as a beverage or a detergent, and a method of manufacturing the same. And a method for manufacturing the same.

[0002]

2. Description of the Related Art Conventionally, as a tubular body formed on a tubular label which is externally fitted to a container such as a beverage or a detergent, for example, both ends of a self-stretchable polyethylene film are formed of a urethane adhesive. And the like are known.

[0003] The tube body is cut into a desired length to form a tubular label (stretch label). The tubular label expands its diameter by applying an external force, and is fitted to a container. The diameter is reduced (substantially restored to the original shape) by removing the external force, and it is used in close contact with a container or the like by the elastic contraction force.

However, in the above-mentioned conventional tube body, the adhesive strength at both ends (hereinafter referred to as "center seal strength") becomes unstable due to uneven application of the adhesive, and the adhesiveness of the adhesive of the polyethylene film is reduced. In order to improve the force (to improve the wettability of the adhesive), it is necessary to perform a corona discharge treatment on the bonding portion. Further, the polyethylene film is formed into a tubular shape, and both ends are bonded together. 25 to cure the agent
24 hours in an aging room maintained at around 40 ℃ to 40 ℃
The tube had to stand still for about 48 hours.

[0005] Therefore, not only does it take a long time to manufacture, but also it is not possible to immediately inspect the bonding condition of the tube body, so that a bonding defect cannot be found at an early stage.
After the manufacture of the tube body, an adhesive defect was found, and it had to be manufactured again from the beginning. 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 polyethylene-based film by irradiating a laser beam in a short time.

[0007]

However, when the both ends of the polyethylene film are bonded by laser light, if the laser light intensity and the irradiation time are used to ensure the adhesion, the entire portion irradiated with the laser light is heated. As a result, the film strength of the bonded portion of the tube body may be reduced.

Further, in order to obtain the optimum laser light intensity and irradiation time for obtaining a sufficient center seal strength without lowering the film strength of the bonded portion of the tube body, it is necessary to finely adjust the bonding conditions. And it was hard to control.

SUMMARY OF THE INVENTION The present invention has been made in view of the above-mentioned problems, and when the overlapping both ends of a film are bonded to each other by a laser beam, a stable center seal strength is ensured while securing the film strength of the bonded portion. It is an object to provide a tube body that can be obtained well and a method for manufacturing the same.

[0010]

SUMMARY OF THE INVENTION The present invention has been made to solve the above-mentioned problems, and the invention according to claim 1 is characterized in that both ends 3 of a printed synthetic resin film 3 are provided.
In a tubular body formed by superposing a and 3b on each other and bonding them by irradiating a laser beam, the film 3 includes a substrate 1 and a surface layer laminated on both sides of the substrate 1. 2, the surface layer 2 is made of a material having a lower melting point than the base material 1, and the both end portions 3a, 3
b, the non-printed portions 4a, 4
b.

According to the first aspect of the present invention, when both ends 3a and 3b which are formed in a cylindrical shape and overlap each other are adhered by laser light irradiation, the surface layers 2 of the both ends 3a and 3b are joined together. It is adhered by softening or melting.

In this case, since the surface layer 2 is made of a material having a lower melting point than that of the base material 1, when the film 3 is heated by irradiating a laser beam, the base material 1 does not reach the melting point. When the surface layer 2 is softened or melted,
They will be bonded together.

[0013] The method of manufacturing such a tube is described in claim 4.
In the method for manufacturing a tube body in which the both ends 3a and 3b of the printed synthetic resin film 3 are overlapped and adhered by irradiating a laser beam as described above, the both sides of the substrate 1 are formed. A surface layer 2 made of a material having a lower melting point than the substrate 1
And the bonding surfaces of the both end portions 3a and 3b are formed on the non-printed portions 4a and 4b on which no printing is performed.

According to the fourth aspect of the present invention, when the both ends 3a and 3b of the film 3 are bonded by a laser beam,
The surface layers 2 at both ends 3a and 3b are bonded by softening or melting.

At this time, since the surface layer 2 is made of a material having a lower melting point than the base material 1, when the film 3 is heated by irradiating a laser beam, the base material 1 does not reach the melting point. Can be softened or melted to bond the surface layers 2 to each other.

Further, the invention according to claim 2 is formed in a cylindrical shape by overlapping both ends 3a and 3b of a printed synthetic resin film 3 and bonding them by irradiating a laser beam. In the tube body, the film 3 includes a substrate 1 and a surface layer 2 laminated on both sides of the substrate 1, and the surface layer 2 is more absorptive of laser light than the substrate 1. It is made of a good material, and the both ends 3a, 3
b, the non-printed portions 4a, 4
b.

According to the second aspect of the present invention, when both ends 3a and 3b which are formed in a cylindrical shape and overlap each other are adhered by irradiation of laser light, the surface layers 2 of the both ends 3a and 3b are joined together. It is adhered by softening or melting.

In this case, since the surface layer 2 is made of a material having better laser light absorption than the substrate 1,
The temperature at which the surface layer 2 is heated more efficiently than the substrate 1 by the irradiation of the laser beam, and the temperature rises faster, and the surface layer 2 is softened or melted to such an extent that the surface layer 2 can adhere to each other in a state where the substrate 1 does not melt. (Hereinafter referred to as “adhesion temperature”), and the surface layers 2 are adhered to each other.

In particular, as set forth in claim 3, the surface layer 2 comprises:
If the material is made of a material having a better laser light absorption property and a lower melting point than the base material 1, the surface layer 2 can more easily reach the bonding temperature.

The method for manufacturing such a tube is described in claim 5.
In the method for manufacturing a tube body in which the both ends 3a and 3b of the printed synthetic resin film 3 are overlapped and adhered by irradiating a laser beam as described above, the both sides of the substrate 1 are formed. A film 3 is formed by laminating a surface layer 2 made of a material having a higher absorptivity of laser light than that of the base material 1, and the adhesive surfaces of the both ends 3 a and 3 b are printed on a non-printed portion 4 a where no printing is performed. , 4b.

According to the fifth aspect of the present invention, when the both ends 3a and 3b of the film 3 are bonded by a laser beam,
The surface layers 2 at both ends 3a and 3b are bonded by softening or melting.

At this time, since the surface layer 2 is made of a material having better laser light absorption than the base material 1, the surface layer 2 is heated more efficiently than the base material 1 by irradiating the laser light, and the temperature rises quickly. Then, the surface layer 2 is allowed to reach the bonding temperature in a state where the base material 1 does not melt, and the surface layers 2 can be bonded to each other.

In particular, the two end portions 3a,
When the laser beam is irradiated from the outer surface of the end 3a, which is the outer side when the 3b is overlaid, and the two ends 3a, 3b are bonded to each other, the surfaces of the both ends 3a, 3b that face each other and come into contact with each other. Since the layer 2 can be efficiently heated to the bonding temperature, the end 3a of the film 3
Can be securely bonded while preventing damage to the surface.

[0024]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS Hereinafter, a first embodiment of a tube body of the present invention will be described with reference to the drawings.

As shown in FIGS. 1 and 2, the tube body of the first embodiment includes a base material 1 and a surface layer 2 having a thickness of 2 to 10 μm laminated on both sides of the base material 1. The self-stretching polyethylene film 3 is formed in a cylindrical shape, and the overlapping both ends 3a and 3b are adhered to each other by irradiation of a laser beam.

On one side of the film 3, a printed layer 4 such as a product name or an instruction is provided on one end 3a of the non-printed portion 4a.
a, and the non-printed portion 4a has the surface layer 2 exposed.

On the other side of the film 3, the surface layer 2 is exposed without printing, and the film 3 is formed into a cylindrical shape so that the print layer 4 is on the inner side. When formed and overlapped with the other end 3b such that the one end 3a is on the outside, the portion of the end 3b that contacts the non-printed portion 4a becomes the non-printed portion 4b. Have been.

The substrate 1 is made of low-density polyethylene having a melting point of 125 ° C.
It is composed of a linear low-density polyethylene (hereinafter, referred to as “metallocene-based polyethylene”) polymerized using a metallocene-based catalyst at ℃. The melting point is measured by a differential calorimeter, and is defined as a peak temperature at the time of temperature rise (measured according to JIS K7122).

As shown in FIG. 3, the film 3 having the above structure is formed in a tubular shape so that the printing layer 4 is on the inner side, and the end 3a having the non-printed portion 4a is on the outer side. Both end portions 3a and 3b are overlapped so that the surface layers 2 (the non-printed portions 4a and 4b) are in contact with each other, and the surface layers 2 (the non-printed portions 4a and 4b) are softened or melted by irradiation with a carbon dioxide gas laser beam. Thus, they are bonded to each other to form a tube.

Next, a method of manufacturing the tube of the first embodiment having the above-described configuration will be described. The film 3 formed in the tube body of the first embodiment guides the low-density polyethylene of the base material 1 and the metallocene-based polyethylene of the surface layer 2 in a molten state by separate extruders and extrudes them 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 layer 4 is provided 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
The film 3 continuously fed is folded into a cylindrical shape by a former 6 and a bending jig (not shown) so that the print layer 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 the center of the former 6 and the non-printing portion 4 is formed.
a, 4b (surface layers 2) are in contact with each other, and a laser beam is radiated from the upper portion on the outer surface side of the overlapping portion by a carbon dioxide laser irradiating device 7, and both ends 3a, 3b are sequentially bonded to each other to form a tube body. Formed.

At this time, the film 3 formed on the tube body of the present embodiment is formed of a material having a lower melting point than the base material 1 because the surface layers 2 provided on both sides of the base material 1 are made of a material. When the laser beam is applied, the surface layer 2 reaches the melting point before the substrate 1. Therefore, both ends 3a, 3b are in a state where the base material 1 is hardly damaged by softening or melting.
The two are adhered to each other, so that the film strength of the adhered portion can be secured.

In particular, even when the film 3 is formed into a cylindrical shape and the both ends 3a and 3b are overlapped with each other and the laser beam is irradiated from the outer surface side of the outer end 3a, the surface layer having a low melting point is obtained. 2 is softened or melted before the substrate 1
Can be bonded in a state where they are not easily damaged by softening or melting, so that the end 3a can be securely bonded while preventing damage to the end 3a.

That is, since the film 3 is not cut even if the film 3 is bonded by a relatively strong laser beam in order to reliably melt the surface layer 2 and obtain a strong center sealing strength, the setting of the bonding processing conditions by the laser beam is performed. As a result of widening,
Easy to control and stable center seal strength can be obtained with good production efficiency.

The tube manufactured by the above method is then cut into appropriate dimensions to form a tubular label (stretch label) 8 as shown in FIG. It is fitted and closely attached to the container 9 by self-shrinkage.

At this time, the tubular label 8 formed from the tube of the present embodiment is attached to both ends 3a, 3b of the film.
Since the surface layers 2 are securely bonded to each other and have a strong center seal strength, there is no possibility that the bonded portions are peeled off.

The polyethylene resin forming the base material 1 and the surface layer 2 includes, in addition to the low-density polyethylene and the metallocene-based polyethylene, linear low-density polyethylene, ethylene-vinyl acetate copolymer, ethylene-ethyl Acrylate copolymers, ionomers and the like are exemplified.

The difference between the melting points of the substrate 1 and the surface layer 2 is preferably as large as possible.
The above effects can be obtained.

Next, a second embodiment of the present invention will be described. The drawings and reference numerals are common to the first embodiment.

As shown in FIG. 1, the film 3 formed on the tube body of the second embodiment includes a base material 1 made of a polyethylene resin and having self-stretching properties, and a surface layer 2.
The surface layer 2 is made of a resin that absorbs laser light energy more easily than the substrate 1, that is, generates heat efficiently by laser light irradiation.

The substrate 1 is made of a linear low-density polyethylene, and the surface layer 2 is made of an ethylene-vinyl acetate copolymer containing 3 to 10% of vinyl acetate. The ethylene-vinyl acetate copolymer of the surface layer 2 is a material having a higher carbon dioxide gas laser light absorption and a lower melting point than the linear low-density polyethylene of the base material 1.

The construction other than the materials of the substrate 1 and the surface layer 2 is the same as that of the first embodiment.

Next, a method of manufacturing the tube body of the second embodiment having the above-described configuration will be described. The film 3 formed on the tube body of the second embodiment is obtained by combining a linear low-density polyethylene constituting the base material 1 and an ethylene-vinyl acetate copolymer constituting the surface layer 2 by separate extruders. It is manufactured by a co-extrusion method in which it is guided in a molten state, extruded from one die and laminated. 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.

Thereafter, as shown in FIG. 4, the film 3 is formed into a tube by the same method as in the first embodiment.

The film 3 formed on the tube body of the second embodiment has a surface layer 2 provided on both sides of the substrate 1.
Since it is made of a material having better laser light absorption than the base material 1, the surface layers 2 (the non-printed portions 4 a, 4
b) When the two are adhered to each other by irradiation of a carbon dioxide gas laser, the surface layer 2 is more efficiently heated than the substrate 1,
As a result, the surface layer 2 reaches the bonding temperature and is bonded with little damage due to softening or melting, so that the film strength of the bonded portion can be secured.

In addition, since the surface layer 2 is made of a material having a lower melting point than the base material 1, the surface layer 2 can easily reach the bonding temperature, and the film strength of the bonding portion can be secured, and the bonding can be performed more efficiently. it can.

In particular, even when the film 3 is formed into a cylindrical shape and the laser light is irradiated from the outer surface of the end 3a, which is the outer side when the both ends 3a and 3b are overlapped, the surface layer 2
Can be heated and softened or melted faster than the base material 1, so that the end portion 3 a can be securely bonded while preventing damage to the end portion 3 a.

That is, since the surface layer 2 has good absorption of laser light, it can be heated even with relatively weak laser light.
In addition, since the substrate 1 is less likely to absorb laser light (less damage) than the surface layer 2, it does not melt or cut even when irradiated with relatively strong laser light. Wider, easier to control,
A stable center seal strength can be obtained with good production efficiency.

The base material 1 may be made of low-density polyethylene, and the surface layer 2 may be made of an ionomer having better laser light absorption than the low-density polyethylene.
The point is that the surface layer 2 may be made of a material that absorbs laser light better than the substrate 1. However, as in the second embodiment, if the surface layer 2 is made of a material having a better laser light absorption and a lower melting point than the substrate 1, the surface layer 2 can be further improved.
Can be efficiently raised to the bonding temperature,
preferable.

In the second embodiment, the surface layer 2 is made of a material that absorbs laser light energy more easily than the base material 1. However, a material that absorbs laser light energy is added to the surface layer 2. It may be. For example, 0.1 to 2% by weight of silica fine powder having a particle size of 0.1 to 5 μm, and 0.1 to 2% by weight of fine particles such as kaolin, diatomaceous earth, epoxy resin and polymethyl methacrylate are added. Is also good. In short, it is only necessary that the surface layer 2 be configured to absorb the energy of the laser light more easily than the base material 1.
For example, the base material 1 may be made of low-density polyethylene, and the surface layer 2 may be a material obtained by adding a laser light absorber to low-density polyethylene polymerized using a metallocene catalyst.

It should be noted that the present invention is not limited to the configuration of each of the above embodiments, and the design can be changed as appropriate within the scope intended by the present invention.

That is, the resin constituting the base material 1 and the surface layer 2 is not limited to the above-mentioned polyethylene-based resin, but a polypropylene-based resin can also be employed.

In the first and second embodiments, a case has been described in which a tubular label (stretch label) 8 using a stretch film (self-stretchable film) 3 as the film 3 forming the tube body. The present invention is also applicable to a case where a heat-shrinkable film is used as the film to form a cylindrical shrink label.

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

The thickness of each of the above-mentioned layers (base material 1, surface layer 2, and printing layer 4) is not particularly limited.

Further, in the first and second embodiments, a film 3 having a three-layer structure of a substrate 1 and surface layers 2 on both sides of the substrate 1 is formed by a co-extrusion method. However, the manufacturing method of the film 3 is not limited to this, and a dry laminating method of laminating a single-layer film of each layer separately formed, or a method of melting the surface layer 2 on both sides of the base material 1 is used. It can be manufactured by a known technique such as an extrusion lamination method of extruding.

In the first and second embodiments, the print layer 4 is provided only on one side of the film 3, but the print layer 4 may be provided on the other side. .
In the case of the present embodiment, the printing layer 4 provided on the other surface side
Is provided except for the non-printing portion 4b at the end 3b.
In short, when the film 3 is formed in a tubular shape, the non-printed portion 4
What is necessary is just to be comprised so that a and 4b may contact and the surface layers 2 may adhere.

Further, the kind of the laser beam is preferably a carbon dioxide gas laser beam which can easily obtain a large capacity, but is not necessarily limited.

[0060]

As described above, in the tube body according to the first aspect, since the surface layer of the film is made of a material having a lower melting point than the base material, both ends which are formed in a cylindrical shape and overlap each other are adhered by laser light. In the case where the surface layer is softened or melted and adhered with little damage due to softening or melting of the base material, the film strength is secured, and laser light for obtaining sufficient center seal strength is obtained. Since the range of conditions such as strength and irradiation time is wide, it is easy to control, and as a result, stable center seal strength can be obtained with good production efficiency.

Further, in the tube body according to the second aspect, since the surface layer of the film is made of a material having a higher absorptivity of laser light than the base material, both ends formed in a cylindrical shape and overlapped by the laser light In the case where the surface layer reaches the bonding temperature with little damage due to softening or melting of the base material when the substrate is bonded, the film strength is secured, and a laser for obtaining sufficient center seal strength is obtained. Since the range of conditions such as light intensity and irradiation time is wide, stable center seal strength can be obtained with high production efficiency.

In particular, if the surface layer is made of a material having a better laser light absorbing property and a lower melting point than the base material, the surface layer can be more quickly brought to the bonding temperature by the irradiation of the laser light. Therefore, more stable center seal strength can be obtained with high production efficiency.

According to the method of manufacturing a tube body of the present invention, when bonding both ends of the film by laser light, the surface layer is softened or melted with little damage due to softening or melting of the base material. As a result, it is possible to efficiently manufacture a tube having a stable center seal strength while securing the film strength of the bonded portion.

Further, according to the method for manufacturing a tube body according to the fifth aspect, when bonding both ends of the film by laser light, the surface layer is heated more efficiently than the base material to soften the base material. Since bonding can be performed in a state where damage due to melting is small, a tube body having a stable center seal strength can be efficiently manufactured while securing the film strength of the bonded portion.

In particular, even when the laser light is irradiated from the outer surface of the outer end when the both ends are overlapped with each other, the substrates are bonded to each other with little damage to the base material. Since the surface layer can be quickly heated to the bonding temperature, it is possible to securely bond while preventing damage to the film.

[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 ... Base material 2 ... Surface layer 3 ... Film 3a, 3b ... Both ends 4a, 4b ... Non-printing part

Continued on front page F-term (reference) 4F100 AK06B AK63A AK63C BA04 BA07 BA10A BA10D BA26 DA02 DB02 EC03 EH20 EJ52 GB17 HB31D JA04A JA04C JD14A JK16 JL12 4F209 AA07 AA08 AA10 AC03 AF10 AG03 AG08 AK03 A03 NG03 A08 AG03 AG08 AK03 TA01 TC08 TD11 TN27

Claims (6)

[Claims] 1. A tubular body formed by superposing two ends (3a) and (3b) of a printed synthetic resin film (3) and bonding them by laser light irradiation. In the above, the film (3)
It comprises a substrate (1) and a surface layer (2) laminated on both sides of the substrate (1), wherein the surface layer (2) is provided on the substrate (1).
Made of a material having a lower melting point than the above-mentioned two ends (3a),
The tube body characterized in that the adhesive surface of (3b) is formed on the non-printed portions (4a) and (4b) where printing is not performed. 2. A tubular body formed by laminating both ends (3a) and (3b) of a printed synthetic resin film (3) and bonding them by laser light irradiation. In the above, the film (3)
It comprises a substrate (1) and a surface layer (2) laminated on both sides of the substrate (1), wherein the surface layer (2) is provided on the substrate (1).
The material is made of a material having a better laser light absorption property, and the bonding surfaces of the both end portions (3a) and (3b) are formed on the non-printed portions (4a) and (4b) where no printing is performed. A tube body characterized by the above. 3. The tube body according to claim 2, wherein the surface layer (2) is made of a material having a lower melting point than the base material (1). 4. A method for producing a tube body by forming a tube by laminating both ends (3a) and (3b) of a printed synthetic resin film (3) and bonding them by laser light irradiation. , A film (3) is formed by laminating a surface layer (2) made of a material having a lower melting point than that of the base material (1) on both sides of the base material (1). A method for manufacturing a tube body, wherein the adhesive surface of (3b) is formed on non-printed portions (4a) and (4b) where printing is not performed. 5. A method of manufacturing a tube body by forming a tube by laminating both ends (3a) and (3b) of a synthetic resin film (3) having been printed thereon and bonding them by laser light irradiation. , A film (3) is formed by laminating a surface layer (2) made of a material having better laser light absorption than the substrate (1) on both sides of the substrate (1). The non-printed portions (4a) and (4b) where no printing is performed are applied to the adhesive surfaces of (3a) and (3b).
A method for producing a tube body, wherein the method comprises: 6. The method for manufacturing a tube body according to claim 4, wherein a laser beam is irradiated from an outer surface side of an end portion (3a) which is an outer side when said both end portions (3a) and (3b) are overlapped. .