JP5172241B2 - Jacket film for heat-shrinkable battery and packaging battery - Google Patents

Description

The present invention has excellent heat resistance, alkali resistance, impact resistance, low / high temperature cycle resistance, and wear resistance, is easy to recycle, and has little shrinkage during storage. The present invention relates to a packaging film using the jacket film for heat treatment and the jacket film for heat shrinkable battery.

Since batteries such as primary batteries and secondary batteries are generally difficult to print directly on the negative electrode surface on the side of the main body, the purpose is to display product names, functions, etc., and to provide electrical insulation and protection. In other words, the battery body is covered with a jacket film in which letters, patterns, and the like are printed on a resin film.
Various performances are required for such a battery jacket film depending on the type of battery to be coated. In particular, since the secondary battery is used repeatedly about 300 to 500 times, the jacket film is required to have many strict quality performances. The contents of the required quality vary depending on the battery manufacturer, the type of secondary battery, etc., but generally the following performance is required.

First, secondary batteries can be heated to high temperatures depending on the conditions of use, or repeated high and low temperatures many times by charging and discharging. Therefore, it is required to have heat resistance, low heat resistance, and high temperature cycle characteristics so as not to cause changes such as misalignment, wrinkles, cracks, and coloring.
In addition, since the secondary battery is used over and over again, there is a risk that the electrolyte will slightly bleed out during use. It is necessary to have resistance to the electrolyte so that no dimensional change occurs.
In addition, in consideration of drop impacts due to repeated use, etc., impact resistance and wear resistance against rubbing operation when taking it in and out of the battery storage part and in and out of the battery charger are also required.

On the other hand, the battery jacket film is required to be easily recycled in addition to the above-described performance. In particular, since secondary batteries can be used repeatedly by charging, they are environmentally friendly. In addition, secondary batteries sold in recent years do not contain harmful substances such as cadmium, lead, and mercury. The demand is increasing day by day, and the demand for recycling of jacket films used for such secondary batteries is rapidly increasing.

In response to these requirements, conventionally, a battery jacket film obtained by printing on a heat-shrinkable film made of a polyvinyl chloride resin has been used. However, the polyvinyl chloride heat-shrinkable film has a problem in terms of environment because dioxins may be generated by combustion. In recent years, for example, a heat-shrinkable film made of a polyolefin-based resin as described in Patent Document 1 has been used as a battery jacket film from the flow of PVC. A heat-shrinkable film made of a polyolefin-based resin has resistance to an alkaline electrolyte and is excellent in impact resistance and low-temperature / high-temperature recyclability.

However, a heat-shrinkable film made of a polyolefin-based resin exhibits a slight shrinkage even under a normal temperature environment. The heat-shrinkable film is usually processed into a tube shape by performing a center seal, and then fitted into the battery tube and thermally shrunk to cover the battery, but a heat-shrinkable film made of polyolefin resin is used. In such a case, shrinkage may occur due to long-term storage or the like, and the battery may not be fitted into the original tube.
International Publication No. WO2005 / 110746

In view of the above situation, the present invention has excellent heat resistance, alkali resistance, impact resistance, low / high temperature cycle resistance, wear resistance, is easy to recycle, and shrinks during storage. An object of the present invention is to provide a jacket film for a heat-shrinkable battery and a packaging battery using the jacket film for a heat-shrinkable battery.

The present invention relates to a heat-shrinkable battery jacket film for coating a battery, and includes a surface layer (A) containing a polyester resin, an intermediate layer (B) containing a polystyrene resin, and a polyester resin. It is the jacket film for heat-shrinkable batteries which has the back surface layer (C) containing this order.
The present invention is described in detail below.

The jacket film for heat-shrinkable batteries of the present invention comprises a surface layer (A) containing a polyester resin, an intermediate layer (B) containing a polystyrene resin, and a back layer (C) containing a polyester resin. It has in this order. In this specification, the surface layer refers to a layer on the outer surface side when the heat-shrinkable battery jacket film is formed, and the back surface layer refers to the inner surface when the heat-shrinkable battery jacket film is formed. This is the side layer.

In the present invention, the surface layer (A) and the back surface layer (C) contain a polyester resin.
As said polyester-type resin, what is obtained by polycondensing dicarboxylic acid and diol is mentioned, for example.

The dicarboxylic acid is not particularly limited. For example, o-phthalic acid, terephthalic acid, isophthalic acid, succinic acid, adipic acid, sebacic acid, azelaic acid, octyl succinic acid, cyclohexanedicarboxylic acid, naphthalenedicarboxylic acid, fumaric acid, Examples include maleic acid, itaconic acid, decamethylene carboxylic acid, anhydrides and lower alkyl esters thereof. The diol is not particularly limited. For example, ethylene glycol, 1,3-propanediol, 1,4-butanediol, diethylene glycol, 1,5-pentanediol, 1,6-hexanediol, dipropylene glycol, triethylene Glycol, tetraethylene glycol, 1,2-propanediol, 1,3-butanediol, 2,3-butanediol, neopentyl glycol (2,2-dimethylpropane-1,3-diol), 1,2-hexane Aliphatic diols such as diol, 2,5-hexanediol, 2-methyl-2,4-pentanediol, 3-methyl-1,3-pentanediol, 2-ethyl-1,3-hexanediol; 2-bis (4-hydroxycyclohexyl) propane, 2,2-bis (4-hydroxy) B carboxymethyl cyclohexyl) alkylene oxide adducts of propane, 1,4-cyclohexane diol, alicyclic diols such as 1,4-cyclohexanedimethanol.

Among these polyester-based resins, those containing a component derived from terephthalic acid as the dicarboxylic acid component and a component derived from ethylene glycol and 1,4-cyclohexanedimethanol as the diol component are preferred. By using such a polyester resin, high low temperature resistance and heat resistance can be imparted to the battery jacket film. When it is desired to further improve the low temperature resistance and heat resistance, the content of the component derived from ethylene glycol is 60 to 80 mol%, and the content of the component derived from 1,4-cyclohexanedimethanol is 10 to 40 mol%. It is preferable to use what is. Such a polyester resin may further contain 0 to 20 mol% of a component derived from diethylene glycol.

As a polyester-type resin contained in the said surface layer (A) and back surface layer (C), the polyester-type resin which has the composition mentioned above may be used independently, and 2 or more types of polyester-type resins which have the composition mentioned above are used. You may use together. Moreover, although the said polyester-type resin is good also as a thing of a different composition by a surface layer (A) and a back surface layer (C), in order to suppress the trouble by the curl etc. of a film, it is preferable to set it as the same composition.

The intermediate layer (B) contains a polystyrene resin.
As the polystyrene resin, an aromatic vinyl hydrocarbon-conjugated diene copolymer, an aromatic vinyl hydrocarbon-aliphatic unsaturated carboxylic acid ester copolymer, or a mixed resin thereof is preferable.

Since the aromatic vinyl hydrocarbon-conjugated diene copolymer is excellent in low-temperature shrinkage, the resulting battery jacket film can be easily coated without generating wrinkles or the like when the battery is coated. .

The aromatic vinyl hydrocarbon-conjugated diene copolymer is not particularly limited, and examples of the aromatic vinyl hydrocarbon include styrene, o-methylstyrene, p-methylstyrene, and the like, and 1,3 as conjugated dienes. -Butadiene, 2-methyl-1,3-butadiene, 2,3-dimethyl-1,3-butadiene, 1,3-pentadiene, 1,3-hexadiene and the like. These may be used alone or in combination of two or more. Of these, a styrene-butadiene copolymer (SBS resin) is preferable because it is particularly excellent in low-temperature shrinkage. In order to produce a film with less fisheye, a styrene-isoprene copolymer (SIS resin) using 2-methyl-1,3-butadiene (isoprene) as a conjugated diene, or a styrene-isoprene-butadiene is used. It is preferable to use a copolymer (SIBS) or the like.

When the SBS resin, SIS resin or SIBS resin is used as the aromatic vinyl hydrocarbon-conjugated diene copolymer, one kind of resin may be used alone, or a plurality of resins may be used in combination. . Moreover, when using in multiple, you may dry blend, and you may use the compound resin kneaded and pelletized using the extruder with a specific composition.

When the SBS resin, SIS resin, or SIBS resin is used alone or in combination, it is preferable that the composition has a styrene content of 65 to 90% by weight and a conjugated diene content of 10 to 35% by weight. By setting it as such a composition, it becomes especially excellent in low temperature shrinkage.
On the other hand, when the styrene content exceeds 90% by weight or the conjugated diene content is less than 10% by weight, it becomes easy to break when a tension is applied to the battery jacket film, and it is unexpected at the time of processing such as printing. May break. If the styrene content is less than 65% by weight or the conjugated diene content is more than 35% by weight, foreign matters such as gels are likely to occur during the molding process, and the waist of the battery jacket film will be weakened. Sexuality may worsen.

Since the aromatic vinyl hydrocarbon-aliphatic unsaturated carboxylic acid ester copolymer is excellent in dimensional stability, the obtained battery jacket film can be hardly contracted in a room temperature environment. .

The aromatic vinyl hydrocarbon-aliphatic unsaturated carboxylic acid ester copolymer is not particularly limited, and examples of the aromatic vinyl hydrocarbon include styrene, o-methylstyrene, p-methylstyrene, and the like. Examples of the unsaturated carboxylic acid ester include methyl acrylate, ethyl acrylate, propyl acrylate, butyl acrylate, methyl methacrylate, ethyl methacrylate, propyl methacrylate, and butyl methacrylate. These may be used alone or in combination of two or more.

When a styrene-butyl acrylate copolymer is used as the aromatic vinyl hydrocarbon-aliphatic unsaturated carboxylic acid ester copolymer, the styrene content is 60 to 90% by weight, and the butyl acrylate content is 10 to 40. It is preferable to use what is weight%. By using the aromatic vinyl hydrocarbon-aliphatic unsaturated carboxylic acid ester copolymer having such a composition, a battery jacket film having excellent low temperature resistance can be obtained.

When a mixed resin of an aromatic vinyl hydrocarbon-conjugated diene copolymer and an aromatic vinyl hydrocarbon-aliphatic unsaturated carboxylic acid ester copolymer is used as the intermediate layer (B), the fragrance in the mixed resin is used. The preferable lower limit of the amount of the group vinyl hydrocarbon-conjugated diene copolymer is 20% by weight, and the preferable upper limit is 100% by weight. If it is less than 20% by weight, the elongation at low temperature is low, and the heat shrinkable battery jacket film may be torn when the battery is accidentally dropped in a low temperature environment. A more preferred lower limit is 30% by weight.

The surface layer (A), the intermediate layer (B), and the back layer (C) have an antioxidant, a heat stabilizer, an antistatic agent, an antiblocking agent, a lubricant, and the like within a range not impairing the essence of the present invention. You may add well-known additives, such as a ultraviolet-ray inhibitor, a light stabilizer, a quencher, a nucleator, a flame retardant, a petroleum resin, and a low density polyethylene.

As a specific configuration of the heat shrinkable battery jacket film of the present invention, the surface layer (A), the intermediate layer (B), and the back surface layer (C) are as shown in (A) / (B) / (C). It is a laminated three-layer structure. Further, an adhesive layer (E) may be interposed between the surface layer (A) and the intermediate layer (B) and / or between the intermediate layer (B) and the back surface layer (C). As a specific configuration in such a case, for example, a four-layer structure of (A) / (E) / (B) / (C) or (A) / (B) / (E) / (C), (A) / (E) / (B) / (E) / (C) 5 layer structure is mentioned.

The adhesive resin contained in the adhesive layer (E) is not particularly limited as long as it is generally commercially available. More preferably, a styrene elastomer, a polyester elastomer, or a modified product thereof is used as the adhesive resin.

The styrenic elastomer includes those composed of polystyrene as a hard segment and polybutadiene, polyisoprene, a copolymer of polybutadiene and polyisoprene as a soft segment, and hydrogenated products thereof. The hydrogenated product may be one obtained by hydrogenating a part of polybutadiene or polyisoprene, or may be one obtained by hydrogenating all of them.

Examples of commercially available styrenic elastomers include “Tuftec”, “Tufprene” (all manufactured by Asahi Kasei Chemicals), “Clayton” (manufactured by Kraton Polymer Japan), “Dynalon” (manufactured by JSR), “Septon”. (Made by Kuraray Co., Ltd.).

Examples of the modified styrenic elastomer include those modified with a functional group such as a carboxylic acid group, an acid anhydride group, an amino group, an epoxy group, and a hydroxyl group.
The preferred lower limit of the content of functional groups such as carboxylic acid groups, acid anhydride groups, amino groups, epoxy groups and hydroxyl groups in the modified styrene elastomer is 0.05% by weight, and the preferred upper limit is 5.0% by weight. It is. If it is less than 0.05% by weight, the adhesion to the front surface layer and the back layer may be insufficient. If it exceeds 5.0% by weight, the resin is thermally deteriorated when the functional group is added. In addition, foreign substances such as gels are likely to be generated. A more preferred lower limit is 0.1% by weight, and a more preferred upper limit is 3.0% by weight.

The polyester elastomer is preferably a saturated polyester elastomer, and particularly preferably a saturated polyester elastomer containing a polyalkylene ether glycol segment. As the saturated polyester-based elastomer containing a polyalkylene ether glycol segment, for example, a block copolymer composed of an aromatic polyester as a hard segment and a polyalkylene ether glycol or an aliphatic polyester as a soft segment is preferable. Furthermore, a polyester polyether block copolymer having a polyalkylene ether glycol as a soft segment is more preferable.

The polyester polyether block copolymer includes (i) an aliphatic and / or alicyclic diol having 2 to 12 carbon atoms, and (ii) an aromatic dicarboxylic acid and / or an aliphatic dicarboxylic acid or an alkyl ester thereof. And (iii) polyalkylene ether glycol as a raw material, and those obtained by polycondensation of oligomers obtained by esterification reaction or transesterification reaction are preferred.

As said C2-C12 aliphatic and / or alicyclic diol, what is generally used as a raw material of a polyester, especially the raw material of a polyester-type elastomer can be used, for example. Specific examples include ethylene glycol, propylene glycol, trimethylene glycol, 1,4-butanediol, 1,4-cyclohexanediol, 1,4-cyclohexanedimethanol and the like. Among these, 1,4-butanediol or ethylene glycol is preferable, and 1,4-butanediol is particularly preferable. These diols may be used alone or in combination of two or more.

As said aromatic dicarboxylic acid, what is generally used as a raw material of polyester, especially a polyester-type elastomer can be used. Specific examples include terephthalic acid, isophthalic acid, phthalic acid, and 2,6-naphthalenedicarboxylic acid. Among these, terephthalic acid or 2,6-naphthalenedicarboxylic acid is preferable, and terephthalic acid is particularly preferable. These aromatic dicarboxylic acids may be used alone or in combination of two or more.

Examples of the alkyl ester of the aromatic dicarboxylic acid include the dimethyl ester and diethyl ester of the aromatic dicarboxylic acid. Of these, dimethyl terephthalate and 2,6-dimethyl naphthalene dicarboxylate are preferable.

The aliphatic dicarboxylic acid is preferably cyclohexane dicarboxylic acid, and the alkyl ester is preferably dimethyl ester or diethyl ester. In addition to the above components, a small amount of a trifunctional alcohol, tricarboxylic acid or ester thereof may be copolymerized, and an aliphatic dicarboxylic acid such as adipic acid or a dialkyl ester thereof may be used as a copolymerization component.

Examples of the polyalkylene ether glycol include polyethylene glycol, poly (1,2- and / or 1,3-propylene ether) glycol, poly (tetramethylene ether) glycol, poly (hexamethylene ether) glycol, and the like. .

The preferable lower limit of the number average molecular weight of the polyalkylene ether glycol is 400, and the preferable upper limit is 6000. By setting it to 400 or more, the block property of the copolymer becomes high, and by setting it to 6000 or less, phase separation in the system hardly occurs and polymer physical properties are easily developed. A more preferred lower limit is 500, a more preferred upper limit is 4000, a still more preferred lower limit is 600, and a still more preferred upper limit is 3000. In addition, in this specification, a number average molecular weight means what was measured by gel permeation chromatography (GPC). The GPC calibration can be performed, for example, by using a POLYTETRAHYDROFURAN calibration kit (manufactured by POLYMER LABORATORIES, UK).

The polyester elastomer may coexist with a rubber component such as natural rubber and synthetic rubber (for example, polyisoprene rubber) and a softening agent such as process oil. By making the softener coexist, the plasticization of the rubber component can be promoted and the fluidity of the resulting thermoplastic resin composition can be improved. The softening agent may be paraffinic, naphthenic, or aromatic. Moreover, in the range which does not impair the effect of this invention, you may add other components, such as resin other than the above, rubber | gum, a filler, an additive, to this resin component and rubber component.

Examples of the filler include calcium carbonate, talc, silica, kaolin, clay, diatomaceous earth, calcium silicate, mica, asbestos, alumina, barium sulfate, aluminum sulfate, calcium sulfate, magnesium carbonate, carbon fiber, glass fiber, and glass bulb. , Molybdenum sulfide, graphite, shirasu balloon and the like. Examples of the additive include a heat resistance stabilizer, a weather resistance stabilizer, a colorant, an antistatic agent, a flame retardant, a nucleating agent, a lubricant, a slip agent, and an antiblocking agent.

As said heat stabilizer, well-known things, such as a phenol type, a phosphorus type, and a sulfur type, can be used, for example. As the weather resistance stabilizer, known ones such as hindered amines and triazoles can be used. Examples of the colorant include carbon black, titanium white, zinc white, red pepper, azo compound, nitroso compound, and phthalocyanine compound. In addition, known antistatic agents, flame retardants, nucleating agents, lubricants, slip agents, antiblocking agents and the like can be used.

Examples of commercially available polyester elastomers include “Primalloy” (manufactured by Mitsubishi Chemical Corporation), “Perprene” (manufactured by Toyobo Co., Ltd.), “Hytrel” (manufactured by Toray DuPont) and the like.

When using a polyester polyether block copolymer composed of polyester and polyalkylene ether glycol as the polyester elastomer, the content of the polyalkylene ether glycol component is preferably 5% by weight, and preferably 90% by weight. is there. When it is 5% by weight or more, it is excellent in flexibility and impact resistance, and when it is 90% by weight or less, it is excellent in hardness and mechanical strength. A more preferred lower limit is 30% by weight, a more preferred upper limit is 80% by weight, and a still more preferred lower limit is 55% by weight. The content of the polyalkylene ether glycol component can be calculated based on the chemical shift of the hydrogen atom and its content using nuclear magnetic resonance spectroscopy (NMR).

The modified polyester elastomer (hereinafter also referred to as a modified polyester elastomer) is obtained by modifying the polyester elastomer using a modifier. The modification reaction for obtaining the modified polyester elastomer is performed, for example, by reacting the polyester elastomer with an α, β-ethylenically unsaturated carboxylic acid as a modifier. In the modification reaction, a radical generator is preferably used. In the modification reaction, a graft reaction in which an α, β-ethylenically unsaturated carboxylic acid or a derivative thereof is added to a polyester elastomer mainly occurs, but a decomposition reaction also occurs. As a result, the modified polyester elastomer has a lower molecular weight and a lower melt viscosity. Further, in the modification reaction, it is generally considered that a transesterification reaction or the like occurs as another reaction, and the obtained reaction product is generally a composition containing unreacted raw materials, etc. The preferable lower limit of the content of the modified polyester elastomer in the obtained reaction product is 10% by weight, the more preferable lower limit is 30% by weight, and the content of the modified polyester elastomer is more preferably 100% by weight.

Examples of the α, β-ethylenically unsaturated carboxylic acid include unsaturated carboxylic acids such as acrylic acid, maleic acid, fumaric acid, tetrahydrofumaric acid, itaconic acid, citraconic acid, crotonic acid, and isocrotonic acid; succinic acid 2 -Octen-1-yl anhydride, 2-dodecen-1-yl anhydride, succinic acid 2-octadecen-1-yl anhydride, maleic anhydride, 2,3-dimethylmaleic anhydride, bromomalein Acid anhydride, dichloromaleic acid anhydride, citraconic acid anhydride, itaconic acid anhydride, 1-butene-3,4-dicarboxylic acid anhydride, 1-cyclopentene-1,2-dicarboxylic acid anhydride, 1,2, 3,6-tetrahydrophthalic anhydride, 3,4,5,6-tetrahydrophthalic anhydride, exo-3,6-epoxy-1,2,3,6-tetra Hydrophthalic anhydride, 5-norbornene-2,3-dicarboxylic anhydride, methyl-5-norbornene-2,3-dicarboxylic anhydride, endo-bicyclo [2.2.2] oct-5-ene-2 , 3-dicarboxylic acid anhydride, and unsaturated carboxylic acid anhydrides such as bicyclo [2.2.2] oct-7-ene-2,3,5,6-tetracarboxylic acid anhydride. Of these, acid anhydrides are preferred because of their high reactivity. The α, β-ethylenically unsaturated carboxylic acid can be appropriately selected according to the copolymer containing the polyalkylene ether glycol segment to be modified and the modification conditions. Good. The α, β-ethylenically unsaturated carboxylic acid can be used by dissolving in an organic solvent or the like.

Examples of the radical generator include t-butyl hydroperoxide, cumene hydroperoxide, 2,5-dimethylhexane-2,5-dihydroperoxide, 2,5-dimethyl-2,5-bis ( Tertiary butyloxy) hexane, 3,5,5-trimethylhexanoyl peroxide, t-butylperoxybenzoate, benzoyl peroxide, dicumyl peroxide, 1,3-bis (t-butylperoxyisopropyl) benzene Organic and inorganic peroxides such as dibutyl peroxide, methyl ethyl ketone peroxide, potassium peroxide, hydrogen peroxide, 2,2′-azobisisobutyronitrile, 2,2′-azobis (isobutylamide) dihalide, 2,2'-azobis [2-methyl-N- (2-hydrido Kishiechiru) propionamide], azo compounds such as azodi -t- butane, carbon radical generating agents such as dicumyl like. The radical generator can be appropriately selected according to the type of polyester elastomer used for the modification reaction, the type of α, β-ethylenically unsaturated carboxylic acid and the modification conditions, and two or more types can be used in combination. May be. Furthermore, the radical generator can be used by dissolving in an organic solvent or the like.

A preferable lower limit of the amount of the α, β-ethylenically unsaturated carboxylic acid is 0.01 parts by weight with respect to 100 parts by weight of the polyester elastomer, and a preferable upper limit is 30.0 parts by weight. When the amount is 0.01 parts by weight or more, the modification reaction can be sufficiently performed, and when the amount is 30.0 parts by weight or less, it is economically advantageous. A more preferred lower limit is 0.05 parts by weight, a more preferred upper limit is 5.0 parts by weight, a still more preferred lower limit is 0.10 parts by weight, and a still more preferred upper limit is 1.0 part by weight.

A preferable lower limit of the blending amount of the radical generator is 0.001 part by weight with respect to 100 parts by weight of the polyester elastomer, and a preferable upper limit is 3.00 part by weight. When the amount is 0.001 part by weight or more, the modification reaction is likely to occur, and when the amount is 3.00 part by weight or less, the material strength is less likely to decrease due to low molecular weight (decrease in viscosity) during modification. A more preferred lower limit is 0.005 parts by weight, a more preferred upper limit is 0.50 parts by weight, a still more preferred lower limit is 0.010 parts by weight, a still more preferred upper limit is 0.20 parts by weight, and a particularly preferred upper limit is 0.10 parts by weight. Part.

As the modification reaction for obtaining the modified polyester-based elastomer, known reaction methods such as a melt-kneading reaction method, a solution reaction method, a suspension-dispersion reaction can be used. Reaction methods are preferred.

In the method using the melt kneading reaction method, the above-described components are uniformly mixed at a predetermined blending ratio, and then melt kneaded. Henschel mixer, ribbon blender, V-type blender, etc. can be used for mixing each component, and Banbury mixer, kneader, roll, uniaxial or biaxial multi-screw kneading extruder etc. are used for melt-kneading. can do.

The preferable lower limit of the kneading temperature when the melt kneading is performed is 100 ° C., and the preferable upper limit is 300 ° C. By setting it within the above range, thermal deterioration of the resin can be prevented. A more preferred lower limit is 120 ° C., a more preferred upper limit is 280 ° C., a still more preferred lower limit is 150 ° C., and a still more preferred upper limit is 250 ° C.

The preferable lower limit of the modification rate (graft amount) of the modified polyester elastomer is 0.01% by weight, and the preferable upper limit is 10.0% by weight. When the content is 0.01% by weight or more, the affinity with the polyester is increased, and when the content is 10.0% by weight or less, a decrease in strength due to molecular deterioration during modification can be reduced. A more preferred lower limit is 0.03% by weight, a more preferred upper limit is 7.0% by weight, a still more preferred lower limit is 0.05% by weight, and a still more preferred upper limit is 5.0% by weight.

The modification rate (graft amount) of the modified polyester elastomer can be obtained from the spectrum obtained by H ¹ -NMR measurement according to the following formula (1). As the equipment used to the ^H 1 -NMR measurement, for example, it can be used to "GSX-400" (manufactured by Nippon Denshi) and the like.

Graft amount (% by weight) = 100 × [(C ÷ 3 × 98) / {(A × 148 ÷ 4) + (B × 72 ÷ 4) + (C ÷ 3 × 98)}] (1)
In the formula (1), A represents an integral value at 7.8 to 8.4 ppm, B represents an integral value at 1.2 to 2.2 ppm, and C represents an integral value at 2.4 to 2.9 ppm.

The preferable lower limit of the JIS-D hardness of the reaction product containing the modified polyester elastomer obtained by the modification reaction is 10, and the preferable upper limit is 80. By setting it to 10 or more, the mechanical strength is improved, and by setting it to 80 or less, flexibility and impact resistance are improved. A more preferred lower limit is 15, a more preferred upper limit is 70, a still more preferred lower limit is 20, and a still more preferred upper limit is 60. The JIS-D hardness can be measured by using a durometer type D by a method in accordance with JIS K 6253.

The minimum with preferable thickness of the jacket film for heat-shrinkable batteries of this invention is 20 micrometers, and a preferable upper limit is 100 micrometers. A more preferred lower limit is 25 μm, a more preferred upper limit is 90 μm, a still more preferred lower limit is 30 μm, and a still more preferred upper limit is 70 μm. Within the above range, excellent heat shrinkability, excellent printing properties such as printing and center seal, and excellent mounting property to the battery can be obtained.

Moreover, the preferable minimum of the thickness of an intermediate | middle layer is 5% of the thickness of the whole jacket film for heat-shrinkable batteries, and a preferable upper limit is 90%. Moreover, the preferable minimum of the thickness of a surface layer is 5% of the thickness of the whole jacket film for heat-shrinkable batteries, and a preferable upper limit is 90%. Moreover, the preferable minimum of the thickness of a back surface layer is 5% of the thickness of the whole jacket film for heat-shrinkable batteries, and a preferable upper limit is 25%. By making the thickness of each layer within the above range, it has heat resistance, alkali resistance, impact resistance, low / high temperature cycle resistance, wear resistance, easy recycling, and shrinkage during storage It can be set as the jacket film for heat-shrinkable batteries with little. Moreover, it is preferable that the thickness of an adhesive layer (E) is 0.5-3.0 micrometers. If the thickness is less than 0.5 μm, sufficient adhesion may not be obtained, and if it exceeds 3.0 μm, the heat shrinkage characteristics may be deteriorated. A more preferable lower limit is 0.7 μm, and a preferable upper limit is 2.0 μm. In the case of forming the adhesive layer (E), the thickness of the adhesive layer (E) is subtracted from the thickness of the intermediate layer (B) or the surface layer (C), whereby the jacket film for heat-shrinkable batteries. The overall thickness can be adjusted.

The thicknesses of the surface layer (A), the intermediate layer (B), the back layer (C) and the adhesive layer (E) are, for example, (A) / (B) / ( When the total thickness is 60 μm, the thickness of the intermediate layer (B) is preferably 3 to 54 μm, and more preferably 6 to 48 μm. Further, the thickness of the surface layer (A) is preferably 3 to 54 μm, and more preferably 6 to 48 μm. The thickness of the back layer (C) is preferably 3 to 15 μm, and more preferably 6 to 12 μm.

When the jacket film for heat-shrinkable battery of the present invention has a five-layer structure of (A) / (E) / (B) / (E) / (C) and the total thickness is 60 μm, the intermediate layer The thickness of (B) is preferably 3 to 53 μm, and more preferably 6 to 46.6 μm. Moreover, it is preferable that the thickness of a surface layer (A) is 3-53 micrometers, and it is more preferable that it is 6-46.6 micrometers. The thickness of the back layer (C) is preferably 3 to 15 μm, and more preferably 6 to 12 μm. The thickness of the adhesive layer (E) is preferably 0.5 to 3.0 μm, and more preferably 0.7 to 2.0 μm.

The heat-shrinkable battery jacket film of the present invention may have a symmetrical configuration in which the thicknesses of the front surface layer (A) and the back surface layer (C) are equal, or may have an asymmetric configuration. From the viewpoint of preventing this problem, a symmetric configuration is preferable. However, the surface layer (A) is required to have durability against scratches and the like as compared with the back surface layer (C). Therefore, when durability against scratches or the like is more required, the jacket film for heat-shrinkable battery of the present invention is further provided on the outer side of the surface layer (A) with a wear-resistant resin layer ( It is preferred to have D). The abrasion-resistant resin layer (D) can be obtained by coating an abrasion-resistant resin forming agent or laminating a film made of a highly transparent resin using a dry lamination method or the like.

The resin constituting the abrasion-resistant resin layer (D) formed by coating or the like has good adhesion to the resin constituting the surface layer (A) and can protect the surface layer (A). The resin is not particularly limited as long as it is a wearable resin, and examples thereof include acrylic resins, urethane resins, polyamide resins, vinyl resins, polyester resins, and silicone resins. Further, ultraviolet or electron beam curable varnish may be used. Among these, acrylic resins and urethane resins are preferable because the wear resistance can be easily controlled.

The thickness of the abrasion-resistant resin layer (D) formed by coating or the like is preferably 0.1 to 5 μm. More preferably, it is 0.3-2 micrometers. If it is less than 0.1 μm, the wear resistance may be insufficient, and if it exceeds 5 μm, the wear-resistant resin layer (D) may be cracked.

When laminating a film made of a highly transparent resin using a dry laminating method or the like, a film made of a polyester resin, a polyamide resin or a polyolefin resin is suitable as the film made of a highly transparent resin. . Furthermore, in order to coat the original tube of the battery beautifully, these films are preferably heat-shrinkable. By using such a film, a heat-shrinkable battery jacket film excellent in heat resistance, impact resistance, low / high-temperature cycle resistance, and wear resistance, and a packaging battery using the heat-shrinkable battery jacket film, can do.
When laminating a film made of a highly transparent resin using the dry laminating method or the like, the thickness of the film to be used is preferably 15 to 60 μm, more preferably 20 to 50 μm. If it is less than 15 μm, the abrasion resistance may be insufficient, and if it exceeds 60 μm, the shrinkage finish to the battery may be deteriorated.

The jacket film for heat-shrinkable batteries of the present invention is usually added to the surface layer (A), intermediate layer (B), back layer (C), abrasion-resistant resin layer (D), and adhesive layer (E). And having a printing layer.

The print layer is preferably formed using gravure ink containing a resin having excellent adhesion such as urethane resin and acrylic resin.
FIG. 1 is a plan view showing an example of the layout of a printed pattern formed on the printed layer of the jacket film for heat-shrinkable batteries of the present invention. As shown in FIG. 1, usually, a printed pattern is printed in a multi-sided manner with a certain gap vertically and horizontally, with a pattern (generally the entire battery side) required for one battery as one unit.
In FIG. 1, reference numeral 2 denotes one unit of printed picture, and a non-printing portion having a distance of D <b> 1 and D <b> 2 is provided in a certain vertical and horizontal gap of the printed picture 2. And it cuts in the vertical direction 3 and the horizontal direction 4 in a non-printing part, and it becomes a heat shrinkable battery jacket film for one battery.
In addition, it is preferable to provide the width of the non-printing portion with an effective width without cut loss. As for the effective width, the vertical width (D1) is determined by the width of the center seal margin, and the horizontal width (D2) is a portion of the cover (folded inward) on the top surface (positive electrode cap side) and bottom surface (negative electrode side) of the battery. ) Determined by width. The vertical width (D1) and horizontal width (D2) are preferably determined in consideration of the degree of thermal contraction when the battery is coated.

Although it does not specifically limit as a method to manufacture the jacket film for heat-shrinkable batteries of this invention, After manufacturing the base film which has a surface layer (A), an intermediate | middle layer (B), and a back surface layer (C) by extrusion molding etc. If necessary, it can be produced by performing processing necessary for battery packaging, such as a printing process, an abrasion-resistant resin layer forming process, and a center sealing process.

The base film is preferably formed by simultaneously forming each layer by a coextrusion method. For example, when the co-extrusion method using a T die is used, it is preferable to use a feed block method, a multi-manifold method, a method using a combination of these, or the like as a lamination method.
Specifically, for example, a polyester resin as a resin constituting the surface layer (A) and a back layer (C), a polystyrene resin as a resin constituting the intermediate layer (B), and an adhesive layer as necessary As the resin to be used, it is possible to use a method in which an adhesive resin is introduced into an extruder, extruded into a sheet shape with a multilayer die, cooled and solidified with a take-off roll, and then stretched uniaxially or biaxially. The stretching temperature needs to be changed according to the softening temperature of the resin constituting the film and the shrinkage characteristics required for the heat-shrinkable battery jacket film, but the preferred lower limit of the stretching temperature is 75 ° C., the preferred upper limit is 120 ° C., and more preferred. The lower limit is 80 ° C, and the more preferable upper limit is 115 ° C.

In addition, in the manufacturing process of the said base film, although wastes, such as an extending | stretching ear | edge, may generate | occur | produce in the process, this waste can also be grind | pulverized and reused. The reuse can be performed by mixing the generated waste with the polystyrene resin of the intermediate layer (B).

In the printing step, a printed image such as a battery pattern is printed on the base film. Although the specific method of printing is not particularly limited, for example, gravure printing using a gravure ink containing a resin having excellent adhesion such as urethane resin and acrylic resin can be used. The printing step may be performed on either the surface layer or the back layer side of the base film, but there is no stain or peeling of the printed image, and the glossiness of the surface layer can be maintained. Therefore, it is preferable to print on the back surface layer (the surface that becomes the inner surface when a tubular film is used).

In the case where the abrasion-resistant resin layer forming step is formed by coating or the like, it is preferably performed after the extrusion sheet forming step of the film forming step, after MD stretching, after TD stretching, or during the printing step.
The abrasion-resistant resin layer (D) formed by coating or the like is coated with a wear-resistant resin layer forming agent in which a resin such as acrylic resin or urethane resin is dissolved or dispersed in a solvent, printed, and then dried. Can be formed. When applying the above-mentioned wear-resistant resin layer forming agent, it is preferable not to selectively apply to the center seal portion described later in terms of facilitating the center seal.

Examples of the solvent used for the abrasion-resistant resin layer forming agent include ketone solvents such as methyl ethyl ketone and acetone, ester solvents such as ethyl acetate, aromatic hydrocarbon solvents such as toluene, and alkanes such as methyl cyclohexane. In addition to solvents, alcohol solvents such as 2-propanol, water, and mixtures thereof.

A lubricant may be added to the wear-resistant resin layer forming agent in order to improve wear resistance. The lubricant is not particularly limited. For example, silicon oil; hydrocarbon wax such as polyethylene wax, polypropylene wax and paraffin wax; fatty acid wax such as stearic acid; higher alcohol wax such as stearyl alcohol; stearamide; Examples include amide waxes such as erucic acid amide and ethylene bis stearic acid amide; ester waxes such as butyl stearate; metal soaps such as calcium stearate; and fluorine waxes.

In order to give a matte texture, inorganic fine particles such as silicon dioxide may be added to the wear-resistant resin layer forming agent.
The preferable lower limit of the average particle diameter of the inorganic fine particles is 0.5 μm, and the preferable upper limit is 10 μm. When the thickness exceeds 10 μm, when printing is performed by the gravure coating method, it is difficult to transfer from the gravure plate to the film substrate, and the abrasion-resistant resin layer may be easily detached due to friction. A more preferred upper limit is 5 μm.
Moreover, the upper limit with preferable content of the said inorganic fine particle is 35 weight%.
Furthermore, you may add various pigments, dyes, etc. to the said abrasion-resistant resin layer forming agent as needed.

The method for applying and printing the abrasion-resistant resin layer forming agent is not particularly limited. For example, methods such as gravure coating, silk screen, and flexo can be used, and gravure coating is preferable.

When laminating a film made of a highly transparent resin using a dry laminating method, etc., after applying an adhesive to one film, the other film is pasted together and dried to provide a wear-resistant resin layer. A jacket film for a heat-shrinkable battery in which (D) is laminated on the surface layer (A) can be obtained.

The battery jacket film of the present invention is usually subjected to the above-described printing process on the base film, cut in the vertical direction, then center-sealed in the center seal process, and cut in the horizontal direction to provide one battery. Is used as a cylindrical film of a size that can be coated (a size that does not cover a part of the positive electrode cap and the negative electrode).

FIG. 2 is a schematic diagram illustrating an example of performing a center sealing process using a center sealing machine. First, after performing the printing process, the long film cut in the vertical direction is folded so that both ends (corresponding to seal margins) of the film overlap each other. Next, an organic solvent is applied to the inner portion of the seal allowance 5 a using the organic solvent discharge nozzle 6. The applied organic solvent 5b comes into a dissolved or swollen state by being in contact with the film. By being fed into the nip roll 7 in this state, it is crimped and wound on the roll 9 in a state where the seal portion 5c is formed.

The center sealing step is preferably performed continuously while traveling in the direction of the arrow in FIG. The preferable lower limit of the center seal speed in the center sealing step is 50 m / min, and the preferable upper limit is 300 m / min. A more preferable lower limit is 130 m / min, and a more preferable upper limit is 200 m / min.

The organic solvent used in the center sealing step is one that dissolves or swells the resin contained in the surface layer (A) and the back surface layer (C) of the base film or the abrasion-resistant resin layer (D). For example, ethyl acetate, tetrahydrofuran, 1,3-dioxolane or ethyl methyl ketone as a main component, and as a diluent solvent, for example, methanol, ethanol, 2-propanol, isopropanol, hexane, cyclohexane, etc. The mixed solvent which mixed is mentioned. When the organic solvent is used, the center sealing step can be performed quickly and stably. Moreover, by using a mixed solvent, the speed of dissolution or swelling can be controlled to an appropriate speed. Further, when such an organic solvent is used, the seal strength at the center seal portion is increased, and peeling does not occur even when exposed to a high temperature atmosphere such as 100 ° C., for example.
In addition to the method of using the organic solvent, the center sealing process can be performed by using other methods such as an adhesive, heat fusion, and high frequency. Since the center seal processing can be performed with the speed, it is preferable to use the method using the organic solvent.

As described above, after the battery jacket film of the present invention formed into a cylindrical film is fitted on a battery such as a primary battery or a secondary battery, the battery jacket film of the present invention is heated at a predetermined temperature. By shrinking, a packaging battery comprising the battery jacket film of the present invention and the battery is obtained. Such a package battery is also one aspect of the present invention.
It does not specifically limit as a battery used for the packaging battery of this invention, Various batteries, such as a primary battery and a secondary battery, can be used.

FIG. 3 is a perspective view showing a state in which the battery jacket film of the present invention as a tubular film is fitted to the battery, and FIG. 4 is a packaged battery in which the battery is covered with the battery jacket film of the present invention. It is the perspective view and bottom view which show an example.
When the battery jacket film of the present invention is used to coat the battery, first, as shown in FIG. 3, the battery jacket film 21 is placed so that the printed pattern 2 of the battery jacket film 21 is positioned on the side surface of the battery 11. Fits on the battery 11. Next, the battery 11 fitted with the battery jacket film 21 is moved over, for example, about 5 to 10 seconds in a hot air tunnel heated to 150 to 220 ° C. As a result, as shown in FIG. 4, a packaged battery in which the surface of the battery 11 excluding the positive electrode portion 11 a, a part of the upper surface and a part of the bottom surface (negative electrode) is coated with the battery jacket film 21 is obtained.
3 and 4 show the case where the shape of the battery is a cylindrical shape, but even when the shape of the battery is other than a cylindrical shape such as a prismatic shape, the battery can be suitably coated similarly.

According to the present invention, heat shrinkage has excellent heat resistance, alkali resistance, impact resistance, low / high temperature cycle resistance, wear resistance, easy recycling, and low shrinkage during storage. A jacket film for a conductive battery and a packaging battery using the jacket film for a heat-shrinkable battery can be provided.

Hereinafter, the present invention will be described in more detail with reference to examples. However, the present invention is not limited to these examples.
Example 1
As the resin constituting the surface layer and the back layer, terephthalic acid is used as the dicarboxylic acid component, 67 mol% of the component derived from ethylene glycol as the diol component, and 33 mol% of the component derived from 1,4-cyclohexanedimethanol A polyester resin was used.
A styrene-butadiene copolymer (styrene 78 wt%, butadiene 22 wt%: Vicat softening point 72 ° C., MFR 5.6 g / 10 min) was used as a resin constituting the intermediate layer.
These resins were put into an extruder having a barrel temperature of 160 to 250 ° C., extruded from a multilayer die at 250 ° C. into a sheet having a three-layer structure, and cooled and solidified by a take-up roll at 30 ° C. Next, roll stretching in the MD direction at a stretching ratio of 1.1 times followed by stretching in the TD direction at a stretching ratio of 6 in a tenter stretching machine in a preheating zone 110 ° C., a stretching zone 90 ° C., and a heat setting zone 80 ° C. By winding with a take-up machine, a base film of a heat-shrinkable multilayer film having a total thickness of 60 μm and a three-layer structure of a surface layer (9 μm) / intermediate layer (42 μm) / back surface layer (9 μm) was obtained.
The surface layer of the obtained base film was coated with a transparent ink containing acrylic resin (Osaka Printing Ink Manufacturing Co., Ltd., overcoat medium EXP-16609) by a gravure coating method, and dried to give a thickness of 1 μm. After forming the wear resin layer, a center seal process was performed to obtain a heat-shrinkable battery jacket film.

(Example 2)
As the resin constituting the surface layer and the back layer, terephthalic acid is used as the dicarboxylic acid component, 67 mol% of the component derived from ethylene glycol as the diol component, and 33 mol% of the component derived from 1,4-cyclohexanedimethanol A polyester resin was used.
A styrene-butadiene copolymer (styrene 78 wt%, butadiene 22 wt%: Vicat softening point 72 ° C., MFR 5.6 g / 10 min) was used as a resin constituting the intermediate layer.
As a resin constituting the adhesive layer, a polyester-based elastomer (manufactured by Mitsubishi Chemical Corporation, Primalloy A1600N, melting point 160 ° C., MFR 5.0 g / 10 min) was used.
By using these resins in the same manner as in Example 1, the thickness was 60 μm, and the surface layer (9 μm) / adhesive layer (1 μm) / intermediate layer (40 μm) / adhesive layer (1 μm) / back surface layer (9 μm) The base film of a heat-shrinkable multilayer film having a five-layer structure was obtained.
The surface layer of the obtained base film was coated with a transparent ink containing acrylic resin (Osaka Printing Ink Manufacturing Co., Ltd., overcoat medium EXP-14008) by a gravure coating method, and dried to give a resistance of 1 μm in thickness. After forming the wear resin layer, a center seal process was performed to obtain a heat-shrinkable battery jacket film.

(Example 3)
As the resin constituting the surface layer and the back layer, terephthalic acid is used as the dicarboxylic acid component, 67 mol% of the component derived from ethylene glycol as the diol component, and 33 mol% of the component derived from 1,4-cyclohexanedimethanol A polyester resin was used.
As a resin constituting the intermediate layer, 100 parts by weight of a styrene-butadiene copolymer (78% by weight of styrene, 22% by weight of butadiene: 72 ° C. Vicat softening point, 5.6 g / 10 min MFR) was used.
As resin constituting the adhesive layer, maleic anhydride-modified styrene-ethylene / butylene-styrene block copolymer (styrene content 30% by weight, maleic anhydride addition amount 0.5% by weight, MFR 4.0 g / 10 min) is used. It was.
By using these resins in the same manner as in Example 1, the thickness was 60 μm, and the surface layer (9 μm) / adhesive layer (1 μm) / intermediate layer (40 μm) / adhesive layer (1 μm) / back surface layer (9 μm) ), A heat-shrinkable multilayer film having a five-layer structure was obtained, and then center seal processing was performed to obtain a heat-shrinkable battery jacket film.

Example 4
Polyester resin containing terephthalic acid as the dicarboxylic acid component, 70 mol% of the component derived from ethylene glycol as the diol component, and 30 mol% of the component derived from neopentylglycol as the resin constituting the surface layer and the back surface layer Was used.
As the intermediate layer, 50 parts by weight of a styrene-butyl acrylate copolymer (82% by weight of styrene, 18% by weight of butyl acrylate: Vicat softening point 62 ° C., MFR 5.5 g / 10 minutes), styrene-butadiene copolymer A mixed resin with 50 parts by weight of a polymer (77% by weight of styrene, 23% by weight of butadiene: 82 ° C. Vicat softening point, 6.0 g / 10 min MFR) was used.
As resin constituting the adhesive layer, maleic anhydride-modified styrene-ethylene / butylene-styrene block copolymer (styrene content 30% by weight, maleic anhydride addition amount 0.5% by weight, MFR 4.0 g / 10 min) is used. It was.
By using these resins in the same manner as in Example 1, the thickness was 60 μm, and the surface layer (9 μm) / adhesive layer (1 μm) / intermediate layer (40 μm) / adhesive layer (1 μm) / back surface layer (9 μm) ), A heat-shrinkable multilayer film having a five-layer structure was obtained, and then center seal processing was performed to obtain a heat-shrinkable battery jacket film.

(Example 5)
As the resin constituting the surface layer and the back layer, terephthalic acid is used as the dicarboxylic acid component, the component derived from ethylene glycol as the diol component is 70 mol%, the component derived from diethylene glycol is 10 mol%, 1,4-cyclohexanedi A polyester resin containing 20 mol% of a component derived from methanol was used.
As an intermediate layer, a compound resin A (84.5% by weight of styrene, 1.5% by weight of isoprene, 14% by weight of butadiene: 70% Vicat softening point) compounded with a styrene-isoprene-butadiene copolymer and a styrene-butadiene copolymer. ° C, MFR 9.0 g / 10 min).
As a resin constituting the adhesive layer, a polyester-based elastomer (manufactured by Mitsubishi Chemical Corporation, Primalloy A1600N, melting point 160 ° C., MFR 5.0 g / 10 min) was used.
By using these resins in the same manner as in Example 1, the thickness was 60 μm, and the surface layer (7 μm) / adhesive layer (1 μm) / intermediate layer (44 μm) / adhesive layer (1 μm) / back surface layer (7 μm) ), A heat-shrinkable multilayer film having a five-layer structure was obtained, and then center seal processing was performed to obtain a heat-shrinkable battery jacket film.

(Example 6)
As the resin constituting the surface layer and the back layer, terephthalic acid is used as the dicarboxylic acid component, 67 mol% of the component derived from ethylene glycol as the diol component, and 33 mol% of the component derived from 1,4-cyclohexanedimethanol A polyester resin was used.
A styrene-butadiene copolymer (styrene 78 wt%, butadiene 22 wt%: Vicat softening point 72 ° C., MFR 5.6 g / 10 min) was used as a resin constituting the intermediate layer.
As the resin constituting the adhesive layer, a modified polyester elastomer (Mitsubishi Chemical Corporation, Primalloy AP IF203, melting point 180 ° C., MFR 30.0 g / 10 min) was used.
These resins were put into an extruder having a barrel temperature of 160 to 250 ° C., extruded from a multilayer die at 250 ° C. into a sheet having a three-layer structure, and cooled and solidified by a take-up roll at 30 ° C. Next, after stretching at a stretching ratio of 6 in a tenter stretching machine having a preheating zone of 110 ° C., a stretching zone of 90 ° C., and a heat setting zone of 80 ° C., the total thickness is 60 μm by winding with a winder. By forming a heat-shrinkable multilayer film comprising 5 layers of (32 μm) / adhesive layer (1 μm) / intermediate layer (18 μm) / adhesive layer (1 μm) / back surface layer (8 μm), and then performing center seal processing, A jacket film for a heat-shrinkable battery was obtained.

(Example 7)
As the resin constituting the surface layer and the back layer, terephthalic acid is used as the dicarboxylic acid component, 67 mol% of the component derived from ethylene glycol as the diol component, and 33 mol% of the component derived from 1,4-cyclohexanedimethanol A polyester resin was used.
A styrene-butadiene copolymer (styrene 78 wt%, butadiene 22 wt%: Vicat softening point 72 ° C., MFR 5.6 g / 10 min) was used as a resin constituting the intermediate layer.
As a resin constituting the adhesive layer, a polyester-based elastomer (manufactured by Mitsubishi Chemical Corporation, Primalloy A1600N, melting point 160 ° C., MFR 5.0 g / 10 min) was used.
These resins were put into an extruder having a barrel temperature of 160 to 250 ° C., extruded from a multilayer die at 250 ° C. into a sheet having a five-layer structure, and cooled and solidified by a take-up roll at 30 ° C. Next, after stretching at a stretching ratio of 6 in a tenter stretching machine having a preheating zone of 110 ° C., a stretching zone of 90 ° C., and a heat setting zone of 80 ° C., the total thickness is 30 μm by winding with a winder A base film of a heat-shrinkable multilayer film having a five-layer constitution of (4 μm) / adhesive layer (1 μm) / intermediate layer (20 μm) / adhesive layer (1 μm) / back surface layer (4 μm) was obtained.
Adhesive (Dainippon Ink Chemical Co., Ltd., LX-401A), curing agent (Dainippon Ink Chemical Co., Ltd., manufactured by Gunze Co., Ltd., Fancy Wrap TAS, thickness 30 μm) SP-60), an adhesive composition containing ethyl acetate in a ratio of 1: 1: 3 was applied, and then bonded to the surface layer of the obtained base film, and 2.5 m × 3 zones (60 ° C.-70 The wear-resistant resin layer was formed by dry lamination to obtain a heat-shrinkable battery jacket film.

(Comparative Example 1)
For the surface layer, the intermediate layer, and the back layer, a polystyrene resin composed of a styrene-butadiene copolymer (78% by weight of styrene, 22% by weight of butadiene: Vicat softening point 72 ° C., MFR 5.6 g / 10 min) is used. After forming a heat-shrinkable multilayer film having a thickness of 60 μm in the same manner as in Example 1, a center-seal process was performed to obtain a heat-shrinkable battery jacket film.

(Comparative Example 2)
For the surface layer, intermediate layer and back layer, terephthalic acid is used as the dicarboxylic acid component, 67 mol% of the component derived from ethylene glycol as the diol component, and 33 mol% of the component derived from 1,4-cyclohexanedimethanol A heat-shrinkable battery jacket film was obtained by performing center seal processing after forming a heat-shrinkable multilayer film of 60 μm using the polyester-based resin contained in the same manner as in Example 1.

(Evaluation)
The following evaluation was performed about the jacket film for heat-shrinkable batteries obtained in Examples and Comparative Examples.
(1) Alkali resistance The obtained heat-shrinkable battery jacket film was immersed in a 30% by weight aqueous KOH solution at room temperature for 24 hours, washed with water and dried. Thereafter, the presence or absence of defects of wrinkles, cracks, tears, loosening of the coating film, peeling of the seal part and blocking was visually observed.
When there was no abnormality mentioned above, it was marked as ◯, and when there was any one, it was marked as x.

(2) Heat resistance The obtained heat-shrinkable battery jacket film is fitted on a secondary battery and moved in a hot-air tunnel heated to 400 ° C. over 2 seconds, whereby a heat-shrinkable battery jacket film is obtained. A secondary battery packaged individually was obtained.
The secondary batteries individually mounted with the obtained tube film were stacked in 10 rows and 2 layers, and this was air-heated at 100 ° C. for 24 hours. When the two-stage upper battery was lifted, the film was visually confirmed and visually observed for wrinkles, cracks, tears, loose coating film, peeling of the seal part, and blocking abnormalities.
When there was no abnormality mentioned above, it was marked as ◯, and when there was any one, it was marked as x.

(3) Impact resistance The secondary battery individually packaged with the jacket film for heat-shrinkable battery obtained in “(2) Heat resistance” was left at room temperature and −20 ° C. for 24 hours. Next, each of the batteries was inclined at 30 degrees so that the negative electrode surface of the battery was downward, and dropped vertically from the 1 m position onto the concrete, and then visually observed for cracks penetrating the film.
When there was no crack, it was marked as ◯, and when there was a crack, it was marked as x.

(4) Low / High Temperature Cycle Resistance The secondary battery individually packaged with the heat-shrinkable battery jacket film obtained in “(2) Heat resistance” was first allowed to stand at −20 ° C. for 1 hour. Subsequently, after heating up to 80 degreeC over 1 hour, it was left to stand at 80 degreeC for 1 hour. After heating at 80 ° C. for 1 hour, it was cooled to the first −20 ° C. over 1 hour. This temperature change of -20 to 80 ° C is regarded as one cycle, and 100 cycles are repeated. Visual observation is made for defects such as wrinkling, cracking, tearing, loosening of the coating film, peeling of the seal part, and blocking, and secondarily. It was also observed visually whether the coating film on the upper and lower surface portions of the battery due to shrinkage was not moved. When there was no abnormality mentioned above, it was marked as ◯, and when there was any one, it was marked as x.

(5) Wear resistance Using the secondary battery individually packaged with the jacket film for heat-shrinkable battery obtained in “(2) Heat resistance”, the battery can be attached to and detached from the charger 500 times. The film was repeatedly observed, and the film was visually observed for scratches and tears.
When there was no scratch or tear, it was marked as ◯, and when there was a scratch or tear, it was marked as x.

(6) Shrinkage at storage The obtained heat shrinkable battery jacket film was cut into MD100 mm × TD100 mm and stored for 7 days in an atmosphere of 40 ° C., and the length L of one side of TD after storage was measured. Then, according to the following formula (2), the shrinkage during storage was compared by obtaining the shrinkage ratio of TD.
In the case where the shrinkage rate was less than 1.5%, it was marked as ◯, and in the case where it was 1.5% or more, it was marked as x.
Shrinkage rate (%) = {(100−L) / 100} × 100 (2)

According to the present invention, it has excellent heat resistance, alkali resistance, impact resistance, low / high temperature cycle resistance, and abrasion resistance, is easy to recycle, and has little shrinkage during storage. A packaging film using the jacket film and the battery jacket film can be provided.

It is a top view which shows an example of the layout of a printing pattern. It is the schematic which shows an example in the case of performing a center sealing process using a center sealing machine. It is a perspective view which shows the state which fitted the battery jacket film of this invention to the battery. It is the perspective view and bottom view which show an example of the packaging battery which coat | covered the battery using the jacket film for batteries of this invention.

Explanation of symbols

2 Print pattern 5a Seal 5b Organic solvent 5c Seal part 6 Organic solvent discharge nozzle 7 Nip roll 9 Roll 11 Battery 21 Battery jacket film 1 / 2d Non-printing part (upper bottom part, lower bottom part)

Claims (6)

A heat-shrinkable battery jacket film for coating a battery,
Surface layer containing a polyester resin (A), the intermediate layer containing a polystyrene-based resin (B), and, possess backside layer containing a polyester resin (C) in this order,
Outside, jacket film further heat shrinkable battery, characterized by chromatic wear resin layer made of acrylic resin or urethane resin (D) of the surface layer (A). The heat-shrinkable battery jacket film according to claim 1, wherein the wear-resistant resin layer (D) has a thickness of 0.1 to 5 μm. The polystyrene resin is an aromatic vinyl hydrocarbon-conjugated diene copolymer, an aromatic vinyl hydrocarbon-aliphatic unsaturated carboxylic acid ester copolymer, or a mixed resin thereof. Or the jacket film for heat-shrinkable batteries of 2. The adhesive layer (E) is provided between the surface layer (A) and the intermediate layer (B) and / or between the intermediate layer (B) and the back surface layer (C). The jacket film for heat-shrinkable batteries according to 2 or 3. The heat-shrinkable battery jacket film according to claim 4, wherein the adhesive layer (E) contains a styrene-based elastomer, a polyester-based elastomer, or a modified product thereof. A package battery comprising the jacket film for heat-shrinkable battery according to claim 1, and a battery.

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