JP2002203525A - Label for battery sheath - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a label for a battery sheath formed by a heat shrinkable film having a high shrinkage initiation temperature wherein a heat shrinkage rate at an equal temperature of heat shrinkage to a conventional one is retained. SOLUTION: In the label for the battery sheath, a printing layer and a thermosensitive adhesive layer are laminated on the heat shrinkable film, made of a polyester containing at least naphthalene dicarboxylic acid as a dicarboxylic acid component of monomer components, wherein one-directional elongation treatment has been made. At least alicyclic diol may be contained as a diol component of monomer components in the polyester of the heat shrinkable film. Cyclohexane dimethanol is contained in the alicyclic diols. The heat shrinkable film is the film wherein the elongation treatment is made three- to five-fold in one direction, and the heat shrinkage rate in such direction may be not less than 30% at 150 deg.C for ten seconds, but not more tan 0.5% at 90 deg.C or less for ten seconds.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a battery packaging label to be attached to a battery such as an alkaline dry battery as a packaging material.

[0002]

2. Description of the Related Art A metal jacket has been used as an exterior material of a dry battery. In recent years, a printing layer has been formed on one side of a heat-shrinkable film and an adhesive layer has been formed on the other side instead. Heat shrinkable adhesive labels are used.
Since this label is thinner than a conventional metal jacket, there is an advantage that the capacity of the battery can be increased. On the other hand, this label requires a release paper to protect the pressure-sensitive adhesive layer until it is mounted on the battery, and this release paper is expensive, and in addition to sticking the release paper to the pressure-sensitive adhesive layer. There is a drawback that work efficiency is poor because an operation and a peeling operation are required. Therefore, as a battery exterior material that does not require such release paper, a heat-shrinkable film is provided with a printing layer on one side and a heat-sensitive adhesive layer made of a heat-sensitive adhesive on the other side. Sexually sensitive labels have been proposed. In such a heat-shrinkable label for a battery exterior, a stretched crystalline polyester is generally used as a label base material. The polyester is widely used because it is a clean material which has excellent strength and rigidity and does not generate toxic gas during incineration.

However, the heat-sensitive adhesive has a low activity, and the heat-shrinkable film made of a conventionally used polyester has a shrinkage initiation temperature (shrinkage rate of the label substrate when heated for 10 seconds). (The lowest temperature exceeding 0.5%) is about 80 ° C., so that when the heat-sensitive adhesive is activated and the heat-sensitive label is attached to the battery, the heat-sensitive adhesive is activated at an excessively high temperature. When heated, the heat-shrinkable film of the label substrate shrinks, and when the label is wound around a dry battery, wrinkles and distortions occur in the label, which leads to a reduction in appearance, and at a low temperature. Activating the heat-sensitive adhesive causes a problem that sufficient adhesiveness cannot be obtained.

Japanese Patent Application Laid-Open No. 9-204908 describes a heat-shrinkable film made of polyethylene terephthalate for use in the exterior of a dry battery having a shrinkage start temperature of 90 ° C. However, although the temperature at which the heat-sensitive adhesive is activated can be increased by increasing the shrinkage initiation temperature, the film becomes brittle due to the thermal history and tends to tear in the longitudinal direction (stretching direction). Furthermore, in the heat-shrinkable film, the heat-shrinkage rate of the film at the same heat-shrinking temperature (about 120 to 160 ° C.) decreases as the shrinkage start temperature increases, so that the mountability to the battery decreases. I do.

[0005]

SUMMARY OF THE INVENTION Accordingly, an object of the present invention is to provide a battery package for a battery exterior formed of a heat-shrinkable film which can be heated and shrunk at the same temperature as the conventional one and has a high shrinkage initiation temperature. Provide labels. Another object of the present invention is to activate the heat-sensitive adhesive at a high temperature,
An object of the present invention is to provide a battery exterior label in which shrinkage of a heat-shrinkable film of a label substrate during activation is suppressed or prevented. Still another object of the present invention is to provide a battery exterior label formed of a heat-shrinkable film having improved brittleness and high tear strength in a stretching direction.

[0006]

Means for Solving the Problems The inventors of the present invention have conducted intensive studies to achieve the above-mentioned object. As a result, when a heat-shrinkable film made of a polyester composed of a specific monomer component is used, the conventional heat-shrinkable film is used. The present invention was found to have a high heat shrinkage while maintaining a high shrinkage initiation temperature.

That is, the present invention relates to a heat-shrinkable film made of a polyester containing at least naphthalenedicarboxylic acid as a dicarboxylic acid component of a monomer component, which is subjected to a unidirectional stretching treatment. The present invention provides a battery exterior label in which layers are laminated.

In the battery packaging label of the present invention, the polyester of the heat-shrinkable film preferably contains at least an alicyclic diol as a diol component of a monomer component. The alicyclic diol may be cyclohexanedimethanol.

In the present invention, the heat-shrinkable film is a film which has been stretched 3 to 5 times in one direction, and has a heat shrinkage in this direction of 30% or more at 150 ° C. for 10 seconds.
In addition, it is preferably 0.5% or less under the condition of less than 90 ° C. for 10 seconds.

[0010]

Embodiments of the present invention will be described below with reference to the drawings. FIG. 1 is a schematic cross-sectional view showing an example of the battery exterior label of the present invention. The label 1 for battery exterior has a printing layer 6 and an overcoat layer 7 sequentially laminated on one side of a label substrate 2 via a primer coat layer 5, and a vapor deposition layer 3 on the other side of the label substrate 2. , The heat-sensitive adhesive layer 4 is laminated.

The label substrate 2 is made of a polyester containing at least naphthalenedicarboxylic acid as a dicarboxylic acid component of a monomer component, and is made of a heat-shrinkable film which has been subjected to a unidirectional stretching treatment. As described above, since the label substrate 2 is constituted by the heat-shrinkable film containing naphthalenedicarboxylic acid as at least a monomer component, the shrinkage start temperature of the label substrate 2 can be increased. It is important that the shrinkage initiation temperature is, for example, 90 ° C. or higher (for example, 90 to 100 ° C.), preferably about 90 to 95 ° C. That is, the heat shrinkage of the label substrate 2 under the condition of less than 90 ° C. for 10 seconds is 0.5% or less. When the temperature is 90 ° C. or higher, the heat shrinkage exceeds 0.5%. If the heat shrinkage at less than 90 ° C. exceeds 0.5%, the label base material 2 shrinks when the heat-sensitive adhesive of the heat-sensitive adhesive layer 4 is activated, and wrinkles and distortions are likely to occur.

In the present invention, the shrinkage starting temperature is 10
It means the temperature at which the label substrate shrinks by more than 0.5% when immersed in a glycerin bath for 2 seconds and heated. In other words, it means the lowest temperature at which the shrinkage of the label substrate exceeds 0.5% when heated by immersion in a glycerin bath for 10 seconds. Regarding the heat shrinkage and the shrinkage start temperature, the time for immersing in the glycerin bath and applying heat is 10 seconds unless otherwise specified.

Further, in the present invention, the label substrate 2 is bonded to the battery with a heat-sensitive adhesive and then heat-shrinks the heat-shrinkable film by applying heat. At the temperature at which the heat shrinkage occurs, a sufficient heat shrinkage is maintained, and a decrease in the heat shrinkage is suppressed or prevented.
That is, the heat shrinkage at the same heat shrinking temperature as in the conventional case is excellent as in the conventional case. The heat shrinkage is, for example, 20% or more, preferably 30% or more.

In the label substrate 2 or the battery exterior label 1, the same heat shrinking temperature as in the prior art is set as follows.
For example, 120 to 160 ° C., preferably 130 to 150
It is about ° C.

Specifically, in the present invention, the heat shrinkable label of the label substrate 2 has a heat shrinkage at 150 ° C. (for 10 seconds) of, for example, 30% or more, preferably 40% or more. is important. Thermal shrinkage at 150 ° C of 3
If it is less than 0%, when the label is wound around the battery so as to thermally shrink in the circumferential direction of the battery, it is difficult to make the upper and lower ends of the label adhere to the upper and lower surfaces of the dry battery by thermal shrinkage. Becomes

In the present invention, as described above, at least naphthalenedicarboxylic acid is used as the dicarboxylic acid component of the monomer component in the polyester of the heat-shrinkable film. In naphthalenedicarboxylic acid, the substitution position of the carboxyl group in the naphthalene ring is not particularly limited. Specifically, as naphthalenedicarboxylic acid, for example, 1,4-naphthalenedicarboxylic acid, 1,5
-Naphthalenedicarboxylic acid, 2,3-naphthalenedicarboxylic acid, 2,6-naphthalenedicarboxylic acid, 2,7-naphthalenedicarboxylic acid, and the like. As the naphthalenedicarboxylic acid, 1,4-naphthalenedicarboxylic acid and 2,6-naphthalenedicarboxylic acid are preferably used. The naphthalenedicarboxylic acids can be used alone or as a mixture of two or more.

The naphthalenedicarboxylic acid is preferably used in combination with one or more other dicarboxylic acids. Examples of dicarboxylic acids that can be used in combination with naphthalenedicarboxylic acid include, for example, terephthalic acid, isophthalic acid,
Aromatic dicarboxylic acids such as 4,4'-biphenyldicarboxylic acid, 3,3'-stilbendicarboxylic acid, 4,4'-stilbenedicarboxylic acid, 4,4'-dibenzyldicarboxylic acid; malonic acid, succinic acid, glutar Aliphatic dicarboxylic acids such as acid, adipic acid, pimelic acid, suberic acid, azelaic acid, sebacic acid and 1,12-dodecandioic acid; 1,4-decahydronaphthalenedicarboxylic acid;
1,5-decahydronaphthalenedicarboxylic acid, 2,6-
Alicyclic dicarboxylic acids such as decahydronaphthalenedicarboxylic acid, 1,4-cyclohexanedicarboxylic acid, and 1,3-cyclohexanedicarboxylic acid; Examples of the dicarboxylic acid preferably used in combination with naphthalenedicarboxylic acid include aromatic dicarboxylic acids such as terephthalic acid and isophthalic acid (particularly, terephthalic acid).

In the dicarboxylic acid component, the proportion of naphthalenedicarboxylic acid is, for example, about 0.5 to 50 mol%, preferably 1 to 30 mol%, more preferably about 5 to 20 mol%, based on the total amount of the dicarboxylic acid component. You can choose from a range. If the proportion of naphthalenedicarboxylic acid is too small, the shrinkage starting temperature of the heat-shrinkable film does not become too high, heat shrinkage is likely to occur, and suppression or prevention of heat shrinkage at a temperature at which the adhesiveness of the heat-sensitive adhesive surely occurs. Is not enough. On the other hand, if the proportion of naphthalenedicarboxylic acid is too large, the film becomes brittle.

The polyester has a dicarboxylic acid component containing at least naphthalenedicarboxylic acid and a diol component as monomer components, and can be obtained by polycondensation of a dicarboxylic acid component and a diol component. The diol component can be used alone or in combination of two or more.

The diol component includes ethylene glycol, propylene glycol, 1,3-propanediol, 2,2-dimethyl-1,3-propanediol, 2-ethyl-2-butyl-1,3-propanediol. , 2-ethyl-2-isobutyl-1,3-propanediol, 1,3-butanediol, 1,4-butanediol, 1,5-pentanediol, 1,6-hexanediol, 2,2,4- Aliphatic diols such as trimethyl-1,6-hexanediol, 2-ethyl-2,4-dimethyl-1,3-hexanediol and 1,8-octanediol; thiodiethanol; polyalkylene glycols such as diethylene glycol; cyclohexanedi Methanols (1,2-cyclohexanedimethanol, 1,1
Alicyclic diols (diols having an alicyclic hydrocarbon ring) such as 3-cyclohexanedimethanol, 1,4-cyclohexanedimethanol, and 2,2,4,4-tetramethyl-1,3-cyclobutanediol And the like.

The diol component preferably contains at least an alicyclic diol. By using at least an alicyclic diol as the diol component of the monomer component, the brittleness of the battery packaging label can be improved, and the tear strength in the stretching direction (vertical direction) can be increased. The alicyclic diol may be one or two kinds.
It may be used in combination of more than one kind.

Among the alicyclic diols, cyclohexanedimethanol is preferred. In cyclohexanedimethanol, the substitution position of the hydroxyalkyl group in the cyclohexane ring is not particularly limited. Specifically, as cyclohexanedimethanol, for example,
Examples thereof include 1,2-cyclohexane dimethanol, 1,3-cyclohexane dimethanol, and 1,4-cyclohexane dimethanol. Preferred cyclohexane dimethanols include 1,4-cyclohexane dimethanol.

In the present invention, the alicyclic diol is preferably used in combination with an aliphatic diol. Aliphatic diols preferably used in combination with alicyclic diols include:
For example, aliphatic diols (particularly, ethylene glycol) such as ethylene glycol, 1,4-butanediol, and diethylene glycol can be used.

In the diol component, the ratio of the alicyclic diol (particularly, cyclohexanedimethanol) is, for example, 40 mol% or less (0 to 4%) based on the total amount of the diol component.
0 mol%), preferably about 30 mol% or less (0 to 30 mol%), more preferably about 25 mol% or less (0 to 25 mol%). If the proportion of the alicyclic diol is too small, the effect of improving the brittleness of the heat-shrinkable film decreases, and the tear strength in the stretching direction does not increase so much. On the other hand, if the proportion of the alicyclic diol is too large,
The friction of the film surface becomes large, the slip with the roll becomes worse in the manufacturing process, and the film cannot be wound well.

In the present invention, the polyester is preferably a polyethylene terephthalate resin containing naphthalenedicarboxylic acid and terephthalic acid as dicarboxylic acid components and cyclohexanedimethanol and ethylene glycol as diol components.

Various additives such as a lubricant, a filler, a heat stabilizer, an antioxidant, an ultraviolet absorber, an antistatic agent, a flame retardant, and a coloring agent are added to the label substrate 2 as necessary. May be.

The thickness of the label substrate 2 can be appropriately selected within a range that does not impair the mechanical strength, the handleability of the label, and the like.
Generally, about 20 to 100 μm, preferably 25 to 60 μm
It is about μm. Note that the label substrate 2 may be composed of a plurality of layers.

The label substrate 2 can be produced by a conventional method used for producing a laminated film, for example, a co-extrusion method. More specifically, for example, one or two
The resin composition can be obtained by melt-extruding at least one kind of resin composition using an extruder, cooling by a cooling roll, and then performing a stretching treatment. In the case where the label base material is formed of a plurality of layers, as a extruder, a confluent feed block two-type and three-layer type extruder equipped with a T die is used, or after forming each single-layer film, Is laminated by a known laminating method, whereby a label substrate formed of a plurality of layers can be produced.

The stretching treatment is carried out, for example, at a temperature of about 70 to 90 ° C. in one direction, preferably in the longitudinal direction (MD direction).
The stretching is performed by 5 times, preferably about 3.3 to 4.6 times. The stretching process may be performed in at least one direction, and may be performed in the other direction (lateral direction) by 1.01 to 1.01.
It may be stretched about 1.1 times. The label substrate 2 thus obtained has an orientation in the direction in which the stretching is performed, and shows a large heat shrinkage in the direction.

When the heat-sensitive adhesive layer 4 is made of a heat-sensitive adhesive, the temperature at which the label base material 2 starts to shrink is determined by the temperature at which the heat-sensitive adhesive layer 4 generates adhesiveness (activation temperature). It is preferable that the temperature is higher by 15 ° C. or more, especially by 20 ° C. or more. According to such a label, when the heat-sensitive adhesive is activated, the label base material 2 does not shrink even if the label base material 2 is attached to the battery after being sufficiently heated to surely exhibit the adhesiveness. The battery can be securely attached to the battery with a good appearance.

The vapor deposition layer 3 is a layer for giving a metallic luster. For example, a metal such as aluminum, nickel or tin is vapor-deposited on the surface of the label substrate 2 by a conventional method such as vacuum vapor deposition. Can be formed. The thickness of the vapor deposition layer 3 is, for example, about 100 to 1000 Å.

As the heat-sensitive adhesive constituting the heat-sensitive adhesive layer 4, a heat-sensitive adhesive commonly used in the field of labels can be used. As the heat-sensitive adhesive, any of a hot-melt heat-sensitive adhesive and a delayed tack-type heat-sensitive adhesive can be used. The heat-sensitive adhesives can be used alone or in combination of two or more.

The hot-melt type heat-sensitive adhesive is a heat-sensitive adhesive having heat melting property and tackiness, and usually comprises a base polymer, a tackifier, a wax and the like.
In the hot-melt type heat-sensitive adhesive, for example, the base polymer is ethylene-vinyl alcohol copolymer, ethylene-vinyl acetate copolymer, ethylene-acrylic acid copolymer, ethylene-methacrylic acid copolymer, ethylene- Olefin hot-melt type heat-sensitive adhesive which is an olefin resin such as methyl acrylate copolymer, ethylene-ethyl acrylate copolymer, ethylene-ethyl acrylate 2-ethylhexyl copolymer, ethylene-ethyl methacrylate; base The polymer is styrene-butadiene-styrene block copolymer (SBS), styrene-isoprene-styrene block copolymer (SIS), styrene-ethylene-butylene-styrene-block copolymer (SE)
BS), a rubber-based hot-melt type heat-sensitive adhesive which is a thermoplastic elastomer such as styrene-ethylene-propylene-styrene block copolymer (SEPS); a polyester-based hot-melt type heat-sensitive adhesive whose base polymer is polyester; A polyamide-based hot-melt type heat-sensitive adhesive whose base polymer is polyamide is included. The base polymer can be used alone or in combination of two or more.

Examples of the tackifier include rosin resins (rosin, polymerized rosin, hydrogenated rosin and derivatives thereof, resin acid dimer, etc.), terpene resins (terpene resin, aromatic modified terpene resin, hydrogenated resin) Examples include terpene resins, terpene-phenol resins, etc., petroleum resins (aliphatic, aromatic, alicyclic), cumarone-indene resins, styrene resins, phenol resins, and the like. The tackifiers can be used alone or in combination of two or more.

On the other hand, in the delayed tack type heat-sensitive adhesive, the surface of the heat-sensitive adhesive after application and drying does not show tackiness at room temperature, but the tackiness is developed by heating, and the tackiness is cooled. It is a heat-sensitive adhesive that lasts for a certain period of time (several minutes to several days) and is usually composed of a thermoplastic resin, a solid plasticizer (crystalline plasticizer), a tackifier, and the like.

Examples of the thermoplastic resin in the delayed tack-type heat-sensitive adhesive include polyacrylate, styrene-acrylate copolymer, styrene-butadiene copolymer, ethylene-vinyl acetate copolymer, and polyacetic acid. Vinyl, vinyl acetate-acrylate copolymer, ethylene-vinyl chloride copolymer, ethylene-
Acrylic ester copolymer, ethylene-acrylic acid copolymer, polybutadiene, polyurethane, styrene-isoprene block copolymer and the like can be mentioned. Among them, an acrylic polymer containing an acrylic acid ester as a monomer component, a vinyl acetate polymer containing vinyl acetate as a monomer component, a styrene polymer containing styrene as a monomer component, and the like are preferable. These thermoplastic resins may be used alone or in combination of two or more.

Examples of the solid plasticizer include phthalic esters such as diphenyl phthalate, dihexyl phthalate, dicyclohexyl phthalate and dihydroabiethyl phthalate; isophthalic esters such as dimethyl isophthalate; terephthalic esters Benzoates such as sucrose benzoate, ethylene glycol dibenzoate, trimethylolethane tribenzoate and pentaerythritol tetrabenzoate; acetates such as sucrose octaacetate; citrates such as tricyclohexyl citrate Sulfonamides such as N-cyclohexyl-p-toluenesulfonamide;
It is not limited to these. These solid plasticizers can be used alone or in combination of two or more. Also,
As the tackifier, the same as described above can be used.

The delayed tack-type heat-sensitive adhesive may contain known or commonly used additives such as a dispersant, an antifoaming agent and a thickener, if necessary.

In the present invention, the activation temperature of the heat-sensitive adhesive layer 4 is preferably 60 ° C. or more (for example, 60 to 100 ° C.).
Degree), more preferably 65 ° C. or higher (for example, 65 to 65 ° C.).
80 ° C.). In a label having a heat-sensitive adhesive layer activated at a temperature of less than 60 ° C., blocking tends to occur when the label is wound or stacked. In the case of a label having a heat-sensitive adhesive layer that requires an excessively high temperature for activation, the heat-shrinkable film serving as the label base material shrinks at the time of heat activation. Labels are likely to wrinkle and warp, and the printed layer is susceptible to damage.

The heat-sensitive adhesive layer 4 may contain various stabilizers, modifiers, and the like, if necessary, in addition to the heat-sensitive adhesive. The heat-sensitive adhesive layer 4 can be formed by a coating method, an extrusion lamination method, or the like, depending on the type of the heat-sensitive adhesive or the like.

Incidentally, an anchor coat layer may be provided between the vapor-deposited layer 3 and the heat-sensitive adhesive layer 4 between the two layers in order to improve the interlayer adhesion. Further, in order to enhance the adhesiveness to the battery, the surface of the heat-sensitive adhesive layer 4 may be subjected to a surface treatment such as a corona discharge treatment.

The primer coat layer 5 is a layer for increasing the adhesiveness of the printing layer 6 to the label substrate 2 and is a known primer, for example, a polyester-based primer, an isocyanate-based primer (such as a two-component primer).
Can be formed. The thickness of the primer coat layer 5 can be appropriately selected within a range that does not impair the transparency and the handleability of the label, and is, for example, about 0.3 to 1.5 μm. Note that the primer coat layer 5 is not necessarily provided.

The printing layer 6 is a layer on which a product name, illustration, handling precautions, etc. are printed and displayed by a known printing method such as letterpress printing, silk screen printing, gravure printing or the like. The printing ink used for forming the printing layer 6 is not particularly limited, and can be appropriately selected according to the printing method. However, the printing ink may be damaged by heat at the time of activating the heat-sensitive adhesive of the heat-sensitive adhesive layer 4. It is preferable to use an ultraviolet curable ink having excellent heat resistance so as not to be affected by heat.

As the UV-curable ink, a commonly used or known UV ink can be used. For example, oligomers such as epoxy acrylate, urethane acrylate and polyester acrylate, and colorants and dispersants such as UV polymerization initiators and pigments, Examples thereof include those blended with monomers such as polyesters containing additives and the like. Representative examples of UV-curable inks include “Best Cure” by Toka Dyeing Chemical Co., Ltd. and “UVAC” by Kuboi Ink Co., Ltd.
E "and" CP-UV "of Matsuikagaku Co., Ltd. and the like. When the printing layer 6 is formed of an ultraviolet curable ink, after printing the ink, the ink is cured by irradiating ultraviolet rays with an ultraviolet lamp.

The overcoat layer 7 is a layer for protecting the print layer 6 and giving it a gloss. The overcoat layer 7 is a transparent ultraviolet-curing varnish, a polyester resin, an acrylic resin, an epoxy resin and, if necessary, a lubricant. It can be formed by coating, printing or the like with a silicone resin or the like. The thickness of the overcoat layer 7 is, for example, about 0.5 to 2 μm. Also, as the ink or varnish, an electron beam-curable type can be used instead of the ultraviolet curable type.

According to the label for battery exterior of the present invention, since it is formed of a heat-shrinkable film which can be heated and shrunk at the same temperature as the conventional one and has a higher shrinkage initiation temperature than the conventional one, Even when the heat-sensitive adhesive is activated at a high temperature, the heat-shrinkable film can suppress or prevent the shrinkage of the heat-shrinkable film, and has good heat-shrinkability even at the same temperature as the conventional one. Therefore, despite the fact that the shrinkage start temperature is higher than before, the temperature at the time of heat shrinking the heat-shrinkable film may be about the same as that of the conventional heat-shrinkable film, or the heat-shrinkable film or the label is suppressed or prevented from deteriorating during heat shrinkage. be able to.

Further, when cyclohexane dimethanol is used as the diol component of the monomer component, the label for battery packaging of the present invention can improve brittleness and can improve mechanical strength (particularly, tear strength in the stretching direction). Is better.

Accordingly, the battery packaging label of the present invention can be used for packaging various batteries such as primary batteries such as lithium batteries and manganese batteries, secondary batteries such as nickel hydride batteries and lithium ion batteries, in addition to alkaline dry batteries. In particular, it is useful as an external label for a cylindrical battery.

Next, a method for attaching the battery exterior label of the present invention to a battery will be described. For example, when attaching the label 1 having the heat-sensitive adhesive layer 4 made of the heat-sensitive adhesive to the battery 8, first, a long film having the same layer structure as the label 1 is cut by a cutter blade or the like. To form a battery exterior label 1 having a desired size, and then heating the label 1 to activate the heat-sensitive adhesive layer 4, which is wound around the peripheral surface of the battery 8 as shown in FIGS. 2 and 3. . At this time, the label 1 is wound so that the direction X (for example, the vertical direction) of the label base material 2 constituting the label 1 in which the stretching process is performed is the circumferential direction of the battery 8. At this time, since the activated heat-sensitive adhesive layer 4 of the label 1 is in contact with the surface of the battery 8, the label 1 is adhered to the peripheral surface of the battery 8 by the heat-sensitive adhesive of the heat-sensitive adhesive layer 4. In addition, at the winding end portion of the label 1, the label 1 itself overlaps and adheres. In addition, it is preferable that the surface of the label 1 be in a state where the primer layer 5 or the printing layer 6 is exposed in order to ensure the adhesiveness of the overlapped portion at this terminal portion.

After that, the battery 8 around which the label 1 is wound is
The label 1 is thermally contracted by supplying it to a heating device heated by hot air or an infrared heater to a temperature at which the label substrate 2 thermally contracts. Thereby, as shown in FIG. 4, the upper and lower ends of the label 1 protruding from both ends of the battery are in close contact with the upper and lower end surfaces 8 a and 8 b of the battery, and the entire label 1 is in close contact with the battery 8. At this time, if the battery is rolled while heating and pressing the outer peripheral surface of the battery 8 with a heating belt or the like, the heat-sensitive adhesive layer 4
Is reactivated, the label 1 is firmly adhered to the outer peripheral surface of the battery 8, and the overlapping portion of the winding end portion of the label 1 is also firmly adhered, so that a battery with the label 1 securely attached is obtained.

These series of steps can be performed using a known label mounting apparatus, for example, an apparatus described in JP-A-9-39929 and JP-A-10-254364.

EXAMPLES The present invention will be described in more detail with reference to the following Examples, which should not be construed as limiting the present invention.

Preparation Example 1 Terephthalic acid: 90 mol% and naphthalene-1,4-dicarboxylic acid: 10 mol% as dicarboxylic acid components, ethylene glycol: 80 mol%, cyclohexane-1,4-dicarboxylic acid
Dimethanol: A copolyester containing 20 mol% as a diol component was heated at a temperature of 26 mm from a T-die using an extruder.
Co-extrusion at 0 ° C, then longitudinal direction at 82 ° C (MD direction)
And heat-set at 110 ° C. to obtain a label substrate having a thickness of 50 μm. When the heat shrinkage in the longitudinal direction (MD direction) of this label substrate was examined at each temperature, the results as shown in Table 1 were obtained. Thus, 90
At 10 ° C. for less than 0.5;
A heat-shrinkable film having a heat-shrinkage ratio of 30% or more at 50 ° C. for 10 seconds was obtained.

[0053]

[Table 1]

Example 1 The composition shown in Table 2, that is, terephthalic acid: 95 mol% and naphthalene-1,4-dicarboxylic acid: 5 mol% as a dicarboxylic acid component, ethylene glycol: 80 mol% and cyclohexane-1 , 4-dimethanol: A polyester containing 20 mol% of a diol component was melt-extruded from a T-die at a temperature of 260 ° C. using an extruder.
By stretching 4 times in the machine direction (MD direction) at 2 ° C,
A label substrate having a thickness of 50 μm was obtained. As shown in Table 3, the heat shrinkage in the longitudinal direction (MD direction) of this label base material was 0.4% at 90 ° C. for 10 seconds, and was 150%.
It was 40.5% under the conditions of 10 ° C. and 10 seconds. Aluminum is vacuum-deposited on one surface of the label base material to a thickness of about 500 angstroms to form a vapor-deposited layer, and on this vapor-deposited layer, an anchor coat agent is applied. , A hot-melt resin mainly composed of an ethylene-vinyl acetate copolymer is melt-extruded and coated to a thickness of 20
μm heat-sensitive adhesive layer (activation temperature of heat-sensitive adhesive layer:
75 ° C.). Next, on the other surface of the label substrate, a primer layer made of a polyester resin (having a thickness of 0.
7 μm) by a coating method, and then printing various display designs with an ultraviolet curable ink using a letterpress rotary printing machine to form a print layer (2.5 μm in thickness), and further form an ultraviolet curable type A transparent varnish made of a resin was applied to form an overcoat layer (thickness: 1 μm). The obtained long film was cut at a predetermined position to obtain a battery exterior label having a desired size. In addition, the printing layer was formed so that the longitudinal direction (MD direction) of the long film was a circumferential direction when the label was attached to the battery. In addition, in order to improve the adhesiveness of the overlapped portion at the end of the label when the label is wound around the battery, about 1 /
Two widths were made to expose the primer coat layer, and the remaining inner half width was made to expose the printed layer. The label obtained in this way, by a known label mounting machine,
By activating the heat-sensitive adhesive layer at 85 ° C., which is about 5 ° C. higher than the conventional temperature, and further thermally shrinking the label base material or the battery exterior label at 130 ° C., which is the same as the conventional temperature. When the battery was continuously mounted on the dry battery, as shown in Table 3, a packaged dry battery having good adhesion to the battery and good appearance with almost no wrinkles or distortion was obtained. The tear strength is 480.
(KJ / m ² ). The tear strength was measured using a Charby impact tester in accordance with JIS K-7111.

Example 2 The composition shown in Table 2, that is, terephthalic acid: 90 mol% and naphthalene-1,4-dicarboxylic acid: 10 mol%
Is a dicarboxylic acid component, melt-extruded a polyester having a diol component of ethylene glycol: 80 mol% and cyclohexane-1,4-dimethanol: 20 mol% from a T-die at a temperature of 260 ° C. using an extruder, Subsequently, it was stretched 4 times in the machine direction (MD direction) at 82 ° C. to obtain a label substrate having a thickness of 50 μm. As shown in Table 3, the heat shrinkage in the longitudinal direction (MD direction) of this label substrate was 0.3% at 90 ° C. for 10 seconds.
It was 40.1% under the conditions of 50 ° C. and 10 seconds. Except for using this label base material, a battery exterior label was prepared in the same manner as in Example 1, wound around a battery, and heat shrunk. As a result, as shown in Table 3, the adhesiveness to the battery was good. Thus, a packaged dry battery having a good appearance without any wrinkles or distortion was obtained. The tear strength is 320
(KJ / m ² ).

Example 3 The composition shown in Table 2, that is, terephthalic acid: 80 mol% and naphthalene-1,4-dicarboxylic acid: 20 mol%
Is a dicarboxylic acid component, melt-extruded a polyester having a diol component of ethylene glycol: 80 mol% and cyclohexane-1,4-dimethanol: 20 mol% from a T-die at a temperature of 260 ° C. using an extruder, Subsequently, it was stretched 4 times in the machine direction (MD direction) at 82 ° C. to obtain a label substrate having a thickness of 50 μm. As shown in Table 3, the heat shrinkage in the longitudinal direction (MD direction) of this label substrate is 0.1% or less (0.
1>) (because of the measurement limit), and 30.5% under the conditions of 150 ° C. and 10 seconds. Except for using this label base material, a battery exterior label was prepared in the same manner as in Example 1, wound around a battery, and heat shrunk. As a result, as shown in Table 3, the adhesiveness to the battery was good. Thus, a packaged dry battery having a good appearance without any wrinkles or distortion was obtained. Further, the tear strength was 250 (KJ / m ² ).

Example 4 The composition shown in Table 2, that is, terephthalic acid: 90 mol% and naphthalene-1,4-dicarboxylic acid: 10 mol%
Is a dicarboxylic acid component, and ethylene glycol: 100
A polyester having mol% as a diol component is melt-extruded from a T-die at a temperature of 260 ° C. using an extruder, and then stretched four times in a machine direction (MD direction) at 82 ° C. to obtain a label base having a thickness of 50 μm. Wood was obtained. As shown in Table 3, the heat shrinkage of the label substrate in the machine direction (MD direction) was 0.5% at 90 ° C. for 10 seconds.
It was 36.2% under the conditions of 50 ° C. and 10 seconds. Except for using this label base material, a battery exterior label was prepared in the same manner as in Example 1, wound around a battery, and heat shrunk. As a result, as shown in Table 3, the adhesiveness to the battery was good. Thus, a packaged dry battery having a good appearance without any wrinkles or distortion was obtained. The tear strength is 210
(KJ / m ² ).

Comparative Example 1 A polyester containing 85 mol% of terephthalic acid and 15 mol% of isophthalic acid as dicarboxylic acid components and 100 mol% of ethylene glycol was melt-extruded from a T-die at a temperature of 260 ° C. using an extruder. Then, it is stretched 4 times in the machine direction (MD direction) at 82 ° C. to give a thickness of 50 μm.
Was obtained. As shown in Table 3, the heat shrinkage in the longitudinal direction (MD direction) of this label substrate was 90%.
It was 1.8% under the conditions of 10 ° C. and 10 seconds, and 46.8% under the conditions of 150 ° C. and 10 seconds. A battery exterior label was prepared in the same manner as in Example 1 except that this label base material was used, and the label was wound around a battery and heat-shrinked. As a result, as shown in Table 3, the heat-sensitive adhesive layer was activated. The label base material or the label for battery exterior shrinks during the formation and adhesion, and the label is wrinkled or distorted. The tear strength is 30.
0 (KJ / m ² ).

Comparative Example 2 99 mol% of terephthalic acid and 1 mol% of isophthalic acid were used as dicarboxylic acid components, and 100 mol% of ethylene glycol was used.
Was extruded from a T-die using an extruder at a temperature of 260 ° C., and then longitudinally (M) at 82 ° C.
By stretching 4 times in the direction D), a label substrate having a thickness of 50 μm was obtained. Vertical direction (MD direction) of this label substrate
As shown in Table 3, the heat shrinkage of
It was 0.5% under the condition of 0 second and 20.0% under the condition of 150 ° C. and 10 seconds. A battery exterior label was prepared in the same manner as in Example 1 except that this label base material was used. The label was wound around a battery and heat-shrinked. As a result, as shown in Table 3, the adhesiveness to the battery was good. However, the shrinkage upon heat shrinkage was low, and the adhesion to the dry battery was low. Also,
The tear strength was 200 (KJ / m ² ).

[0060]

[Table 2]

[0061]

[Table 3]

From Table 3, it can be seen that the label for battery exterior made of the label base material according to the example has a high shrinkage initiation temperature, and the label base material undergoes heat shrinkage even when the heat-sensitive adhesive is activated at a high temperature. Not or rarely. Therefore, even if the battery is firmly adhered to the battery, the appearance of the battery does not cause wrinkles or distortion at all.

Further, the heat-shrinkage rate at the same temperature as that of the conventional battery exterior label made of the label base material according to the example is the same as the conventional one, and the heat shrinkage of the label base material is the same as the conventional one. Can be done at temperature.

In particular, the battery packaging label obtained by using cyclohexanedimethanol as the diol component has high tear strength and improved brittleness. That is,
Good tearability in the vertical direction.

[0065]

The label for battery exterior of the present invention uses a label base made of polyester containing a specific monomer component, so that the conventional heat shrinkage at the temperature for heat shrinkage is maintained, and It has a high shrinkage initiation temperature, and even if the heat-sensitive adhesive is activated at a high temperature, the shrinkage of the heat-shrinkable film of the label substrate during the activation is suppressed or prevented. Therefore, the heat-sensitive adhesive can be activated at a higher temperature than in the past, and the label can be securely and firmly adhered to the battery. Further, the tear strength in the longitudinal direction can be increased, and the brittleness can be improved.

[Brief description of the drawings]

FIG. 1 is a schematic sectional view showing an example of a battery exterior label of the present invention.

FIG. 2 is a partial cross-sectional view showing a state where the battery exterior label of the present invention is wound around a battery.

FIG. 3 is a partial sectional view taken along line III-III of FIG. 2;

FIG. 4 is a partial cross-sectional view showing a state in which the battery exterior label of the present invention is attached to a battery.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Battery exterior label 2 Heat-shrinkable film (label base material) 3 Deposition layer 4 Heat-sensitive adhesive layer 5 Primer coat layer 6 Printing layer 7 Overcoat layer 8 Battery

Continued on the front page (51) Int.Cl. ⁷ Identification symbol FI Theme coat II (reference) B29L 7:00 B29L 7:00

Claims (6)

[Claims] 1. A printing layer and a heat-sensitive adhesive layer are laminated on a heat-shrinkable film made of a polyester containing at least naphthalenedicarboxylic acid as a dicarboxylic acid component of a monomer component and subjected to a unidirectional stretching treatment. Battery exterior label. 2. The battery packaging label according to claim 1, wherein the polyester of the heat-shrinkable film contains at least an alicyclic diol as a diol component of a monomer component. 3. The battery packaging label according to claim 2, wherein the alicyclic diol is cyclohexanedimethanol. 4. The ratio of naphthalenedicarboxylic acid is 0.1 to the total amount of dicarboxylic acid component as a monomer component.
The battery exterior label according to claim 1, wherein the content is 5 to 50 mol%. 5. The battery packaging label according to claim 2, wherein the proportion of the alicyclic diol is 40 mol% or less based on the total amount of the diol component as the monomer component. 6. The heat-shrinkable film is a film that has been stretched 3 to 5 times in one direction, and has a heat shrinkage of 15
30% or more at 0 ° C for 10 seconds and 90 ° C
The battery exterior label according to any one of claims 1 to 5, wherein the content is 0.5% or less under a condition of less than 10 seconds.