JPH09302109A - Thermally shrinkable tube for electric cell - Google Patents

Abstract

PROBLEM TO BE SOLVED: To obtain a thermally shrinkable tube for covering electric cell, excellent in opening property, lubricating property, shrink property and liquid leakage preventing property. SOLUTION: This thermally shrinkable tube comprises a block copolymer composition containing (a) 50-100 pts.wt. block copolymer having (60/40) to (90/10) polymerization ratio of a vinyl aromatic hydrocarbon to conjugated diene and having a block represented by the formula (S-B)n [S is a vinyl aromatic hydrocarbon polymer block; B is a random copolymer part composed of a vinyl aromatic hydrocarbon and a conjugated diene; (n)>=2], (b) 0-50 pts.wt. vinyl aromatic hydrocarbon-based polymer, (c) 0.01-50 pts.wt. inorganic filler based on 100 pts.wt. total amount of the components (a) and (b) and (d) 0.01-15 pts.wt. lubricant based on 100 pts.wt. total amount of the components (a) and (b). The tube has >=5% vertical shrinkage factor and >=40% lateral shrinkage factor in immersing in 85 deg.C hot water for 5sec.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention mainly relates to a battery coating (interior) tube having excellent openability, lubricity, shrinkability, and liquid leakage prevention, and a printed indication of quality, specifications, etc. For heat-shrinkable tubes for battery packaging for automobiles.

[0002]

2. Description of the Related Art A dry cell is manufactured by coating a unit cell with a heat-shrinkable tube and then mounting a metal can. This heat-shrinkable tube is formed into a film by a tubular method or the like, but it is in a state of being wound around a paper tube after being flattened by a nip roll or the like, and at the time of actually manufacturing a dry cell, at a very high speed, It goes through the steps of cutting, opening, insertion of unit cells, and heat shrinkage. Therefore, the heat-shrinkable tube is required to have good openability, smoothness, and high-speed shrinkability.

[0003]

Polyvinyl chloride has been mainly used as a tube for coating a dry battery until now, but development of an alternative product has been desired due to environmental problems in recent years. Further, JP-A-6-122808 discloses a random copolymer containing a block copolymer having a styrene-based hydrocarbon block and a conjugated diene-based hydrocarbon block and a styrene-based hydrocarbon and having a glass transition temperature of 40 to 90 ° C. Examples of the tube include a tube obtained by stretching a composition containing a copolymer as a main component. JP-A-6-349501 discloses a block copolymer composed of a styrene-based hydrocarbon and a conjugated diene-based hydrocarbon or a block copolymer thereof. A stretched tube of a mixture prepared by adding impact polystyrene to a mixed polymer prepared by blending a styrene-based polymer with the polymer is mentioned.
However, the lateral shrinkage ratio in the width direction becomes 4 only after soaking these tubes in hot water at 100 ° C for 30 seconds or 10 seconds.
Since it is 0% or more, it is said that the lateral shrinkage rate is 40% or more and the longitudinal direction shrinkage rate is 5% or more when immersed in hot water of 85 ° C., which is the current polyvinyl chloride heat-shrinkable tube, for 5 seconds. Since it is insufficient to be applied to a high-speed dry battery manufacturing apparatus that requires heat shrinkability, the appearance of an alternative heat shrinkable tube having performance closer to that of polyvinyl chloride has been desired.

[0004]

[Means for Solving the Problems] Under these circumstances,
The present inventors have found that by using a composition in which an inorganic filler and a lubricant are added to a vinyl aromatic hydrocarbon-conjugated diene copolymer having a specific structure or a copolymer composition containing the same, the open property can be improved. Further, they have found that it is possible to obtain a heat-shrinkable tube for coating a battery, which is excellent in lubricity, shrinkability, and prevention of liquid leakage, and have completed the present invention.

That is, the present invention provides the following (a), (b),
The present invention relates to a heat-shrinkable tube for a battery, which is composed of a block copolymer composition containing (c) and (d). (A) The weight ratio of vinyl aromatic hydrocarbon to conjugated diene is 6
0/40 to 90/10 and at least a general structural formula of-(SB) _n- (S is a vinyl aromatic hydrocarbon polymer block, B is a random aromatic vinyl hydrocarbon and a conjugated diene. Copolymerization part, n is an integer of 2 or more)
A block copolymer having a block represented by: 5
0-100 parts by weight. (B) Vinyl aromatic hydrocarbon polymer: 0 to 50 parts by weight. However, the total of (a) and (b) is 100 parts by weight. (C) Inorganic filler: 0.01 to 50 parts by weight based on 100 parts by weight of the total of (a) and (b). (D) Lubricant: 0.01 to 15 parts by weight based on 100 parts by weight of the total of (a) and (b).

Further, according to the present invention, when immersed in hot water at 85 ° C. for 5 seconds, the shrinkage is such that the longitudinal shrinkage in the length direction of the tube is 5% or more and the transverse shrinkage in the width direction is 40% or more. The present invention relates to a heat-shrinkable tube for a battery. Further, the present invention relates to the heat-shrinkable tube for a battery, wherein the cut surface of the tube has an adhesive strength of 40 g / cm or less and the inner surface of the tube has a static friction coefficient of 0.30 or less.

[0007]

DESCRIPTION OF THE PREFERRED EMBODIMENTS The present invention will be described below in detail.
The weight ratio of the vinyl aromatic hydrocarbon to the conjugated diene in the block copolymer composed of the vinyl aromatic hydrocarbon and the conjugated diene used in the present invention is 60/40 to 90/10, preferably 70/30 to 85. / 15. If the vinyl aromatic hydrocarbon and the conjugated diene are less than 60/40, the rigidity of the resin is lowered, and if it exceeds 90/10, the impact resistance is lowered and it cannot be put to practical use.

The block copolymer composed of a vinyl aromatic hydrocarbon and a conjugated diene used in the present invention has at least the general structural formula:-(SB) _n- (S is a vinyl aromatic hydrocarbon polymer block, B is a random copolymerization part consisting of vinyl aromatic hydrocarbon and conjugated diene, n is a block represented by 2 or more), and the vinyl aromatic hydrocarbon and conjugated diene are contained in the block. The vinyl aromatic hydrocarbon in the random copolymerization part may be evenly distributed or tapered. As the block copolymer, one having a general structure of-(S-B) _n- S (S, B and n are the same as those described above) is particularly preferable. In the present invention, this block copolymer may be used alone or in a mixture of two or more kinds. The block copolymer is at least-(SB) _n- (n≥2)
Without the structure represented by, the resulting tube cannot obtain good shrinkability, that is, sufficient shrinkage rate and shrinkage rate. Specifically, when immersed in hot water of 85 ° C for 5 seconds,
It is necessary to have a heat shrinkage ratio of 40% or more in the lateral direction and 5% or more in the longitudinal direction, and a block copolymer having a structure other than the above structure cannot sufficiently realize these physical properties.

The number average molecular weight of the block copolymer is not limited, but it is preferably 100,000 to 300,000.

The block ratio of vinyl aromatic hydrocarbon is not limited, but it is preferably 50 to 90% by weight.
The block ratio of the vinyl aromatic hydrocarbon is the block ratio (%) = (W / W ₀ ) × 100 (where W = the weight of the vinyl aromatic hydrocarbon block in the block copolymer, and W ₀ = the block copolymer). The total weight of vinyl aromatic hydrocarbons in the polymer is shown).
Here, the total weight of vinyl aromatic hydrocarbons in the block copolymer is the weight of all vinyl aromatic hydrocarbons subjected to the polymerization, and the weight of the vinyl aromatic hydrocarbon block is the ozone decomposition of the block copolymer. [Y. TANAKA, et.
al. , RUBBER CHEMISTRY AND
TECHNOLOGY, 58 , 16 (1985)] GPC of the obtained vinyl aromatic hydrocarbon polymer component
In the measurement (using an ultraviolet spectroscopic detector with the wavelength set to 254 nm as a detector), the molecular weight corresponding to each peak was determined from a calibration curve prepared using standard polystyrene and a styrene oligomer, and the number average molecular weight exceeded 3,000. It can be determined quantitatively from the peak area.

The vinyl aromatic hydrocarbon used in the present invention is styrene, o-methylstyrene, pt
There are ert-butyl styrene, α-methyl styrene, vinyl naphthalene, and the like, but styrene is particularly common.

As the conjugated diene used in the present invention, 1,3-butadiene, 2-methyl-1,3-butadiene (isoprene), 2,3-dimethyl-1,3-butadiene, 1,3-pentadiene, 1 , 3-hexadiene and the like, but particularly common examples include 1,3-butadiene and isoprene.

The block copolymer of the present invention can be produced by polymerizing an organolithium compound in a hydrocarbon solvent as an initiator. As the organic solvent, butane, pentane, hexane, isopentane, heptane, octane, aliphatic hydrocarbons such as isooctane, cyclopentane, methylcyclopentane, cyclohexane, methylcyclohexane,
Alicyclic hydrocarbons such as ethylcyclohexane or aromatic hydrocarbons such as benzene, toluene, ethylbenzene and xylene can be used.

The organolithium compound is a compound having one or more lithium atoms bonded in the molecule, and is a monofunctional organolithium compound such as n-propyllithium, isopropyllithium, n-butyllithium or sec-butyllithium. , Polyfunctional organolithium compounds such as hexamethylenedilithium and isoprenyldilithium.

The vinyl aromatic hydrocarbon and the conjugated diene of the block copolymer include one type or two types of the above-mentioned monomers, respectively.
One or more species can be selected and used for polymerization.

In the present invention, the molecular weight of the block copolymer can be controlled by the amount of the initiator added to the total amount of the monomers added.

The block ratio of the block copolymer can be controlled by the addition amount of the randomizing agent when the vinyl aromatic hydrocarbon and the conjugated diene are copolymerized. As the randomizing agent, tetrahydrofuran (THF), ethers such as diethyl ether, tertiary amines such as triethylamine,
Triphenylphosphine, hexamethylphosphoramide, potassium alkylbenzene sulfonate, etc. are used. The addition amount is preferably 0.001 to 10 parts by weight with respect to 100 parts by weight of all charged monomers. The time of addition may be before the initiation of the polymerization reaction or before the polymerization of the random portion. Further, it may be added additionally if necessary.

In addition, the block ratio can be controlled by mechanically continuously feeding the vinyl aromatic hydrocarbon and the conjugated diene to the polymerization vessel or alternately adding the vinyl aromatic hydrocarbon and the conjugated diene to the polymerization vessel in small amounts. it can.

The vinyl aromatic hydrocarbon-based polymer used in the present invention includes (i) vinyl aromatic hydrocarbon polymer, (ii) vinyl aromatic hydrocarbon and (meth) acrylic acid copolymer. , (Iii) a copolymer of vinyl aromatic hydrocarbon and (meth) acrylic acid ester, (iv)
It is at least one polymer selected from rubber-modified styrene polymers.

The vinyl aromatic hydrocarbon polymer (i) is a homopolymer of the above-mentioned vinyl aromatic hydrocarbon or 2
One or more copolymers are used. Particularly common is polystyrene.

(Ii) vinyl aromatic hydrocarbon and (meth)
The copolymer with acrylic acid can be obtained by polymerizing the above vinyl aromatic hydrocarbon and (meth) acrylic acid, and each monomer may be used alone or in combination of two or more for the polymerization. . Examples of (meth) acrylic acid include acrylic acid and methacrylic acid.

The copolymer (iii) of a vinyl aromatic hydrocarbon and a (meth) acrylic acid ester can be obtained by polymerizing the above vinyl aromatic hydrocarbon and a (meth) acrylic acid ester. Each monomer can be used alone or in combination of two or more.

Examples of the (meth) acrylic acid ester include methyl acrylate, ethyl acrylate, n-butyl acrylate, isobutyl acrylate, hexyl acrylate, (2-ethyl) hexyl acrylate, methyl methacrylate, ethyl methacrylate. , Butyl methacrylate, (2-hydroxy) ethyl methacrylate and the like.

The rubber-modified styrenic polymer (iv) is obtained by polymerizing a mixture of vinyl aromatic hydrocarbon or a monomer copolymerizable therewith and various elastomers. The above-mentioned ones are used as the vinyl aromatic hydrocarbon, and as the monomer copolymerizable with this,
(Meth) acrylic acid, (meth) acrylic acid ester and the like are used. As the elastomer, butadiene rubber, styrene-butadiene rubber, styrene-butadiene block copolymer elastomer, chloroprene rubber,
Natural rubber or the like is used. A rubber-modified impact-resistant styrene resin (HIPS) is mentioned as a particularly preferable rubber-modified styrene polymer.

In the present invention, the weight ratio of (a) block copolymer of vinyl aromatic hydrocarbon and conjugated diene / (b) vinyl aromatic hydrocarbon polymer is 50/50 to 100 /.
It is preferably 0. When blending (b),
From the viewpoints of maintaining the tensile strength of the present tube and maintaining the strength of the resin at the time of stretching (in a heated state), that is, film forming property, it is desirable that the glass transition temperature of (b) exceeds 90 ° C.

In the present invention, it is essential to use the inorganic filler of (c) and the lubricant of (d) together with the block copolymer of (a) and the polymer of (b). Component (c)
Alternatively, in the tube containing only (d), the opening property is insufficient due to adhesion of the cut surface of the tube, and therefore the insertion of the unit cell is not always successful. However, by using the components (c) and (d) in combination, the synergistic effect greatly improves the opening property, and the cell can be inserted without any trouble.

As the inorganic filler (c) used in the present invention, silica is preferable, but titanium oxide, calcium carbonate, alumina, carbon black, aluminum silicate, aluminum hydroxide, talc, clay, dolomite. , Magnesium hydroxide, kaolin, glass beads and the like can also be used. These may be used alone or in combination of two or more. Further, these inorganic fillers are subjected to various surface treatments for the purpose of improving the bonding force at the interface with the block copolymer (a) or the vinyl aromatic hydrocarbon polymer (b), or improving the dispersibility. Heat treatment, surfactant treatment, silane coupling agent treatment, etc.) may be applied.

The amount of the inorganic filler compounded is 1 based on the sum of the block copolymer (a) and the vinyl aromatic hydrocarbon polymer (b).
The amount is preferably 0.01 to 50 parts by weight, more preferably 0.1 to 20 parts by weight, per 00 parts by weight.

The particle size of the inorganic filler to be used is not particularly limited, but the average particle size is preferably 0.01 to 100 μm, more preferably 0.5 to 50 μm, and the inorganic fillers having different particle sizes are preferable. It is also possible to use together. Specifically, if a filler of less than 5 μm and a filler of 5 μm or more are used together, the opening property will be further improved.

The lubricant used in the present invention includes hydrocarbon lubricants such as microcrystalline wax and polyethylene wax, fatty acid lubricants such as stearic acid, stearic acid amide, N, N'-ethylenebisstearic acid amide and stearic acid. Fatty acid amide lubricants such as monomethylolamide, N-stearyl stearic acid amide, N, N'-distearyl adipic acid amide, ester lubricants such as glycerin fatty acid ester, sorbitan fatty acid ester, montan wax, lead stearate, stearic acid Examples thereof include metal soap-based lubricants such as zinc, alcohol-based lubricants, high-molecular-weight lubricants (for example, Metablen L manufactured by Mitsubishi Rayon Co., Ltd.), and the melting point is preferably 70 ° C. or higher. Among these, one kind or two or more kinds can be selected and used.

The amount of the above-mentioned lubricant compounded is 10 based on the sum of the block copolymer (a) and the vinyl aromatic hydrocarbon polymer (b).
The amount is preferably 0.01 to 15 parts by weight, more preferably 0.1 to 10 parts by weight, based on 0 parts by weight. The static friction coefficient and the dynamic friction coefficient showing the slipperiness are the usual values (0.40 or less: Nikkan Kogyo Shimbun, Showa 45) for general plastic packaging films.
Published by Yoshisaku Takahashi Plastic film, published in 1979 by Shozo Yamaguchi Mechanical properties of plastics
However, the coefficient of static friction on the inner surface is 0.30.
The following is preferred.

If desired, various additives may be added to the block copolymer composition of the present invention. Examples of the additives include various stabilizers, antistatic agents, antiblocking agents, antifog agents, light resistance improving agents, softening agents, plasticizers, processing aids, pigments, dyes, flame retardants and the like.

<Production of Heat-Shrinkable Tube> The heat-shrinkable tube for battery of the present invention comprises a block copolymer (a), a vinyl aromatic hydrocarbon polymer (b) and an inorganic filler (c). It is obtained by extrusion-stretching the composition comprising the lubricant of (d). The method for producing the composition may be any known method. For example, it may be dry blended with a Henschel mixer, a ribbon blender, a super mixer, a V blender, or the like, and may be melted with an extruder and pelletized. Of these, melt mixing is preferable.

The heat-shrinkable tube made from the above block copolymer composition is produced by simultaneously or separately drawing a tube by a known tubular method in the length direction and the circumferential direction. Alternatively, a biaxially stretched film obtained by stretching a wide film or a flat film from a T-die in a direction perpendicular to the length direction may be processed into a tube shape by a known method to be manufactured.

In the present invention, the stretching temperature is 60 to 120.
C is preferred. The stretching ratio is not particularly limited, but is 1.1
-8 times is preferable. However, when the film is slightly stretched in one direction in order to improve the finish after contraction, the stretching ratio may be smaller than this range. The heat shrinkage required for this tube is 40% or more in the lateral direction and 5% or more in the longitudinal direction when immersed in hot water at 85 ° C. for 5 seconds. A tube having no further heat-shrinkability cannot be used in the high-speed dry battery manufacturing apparatus currently used for a polyvinyl chloride heat-shrink tube. The thickness of the tube is preferably 10 μm to 300 μm.

[0036]

EXAMPLES The present invention will be described in detail below with reference to examples. However, the present invention is not limited to the following examples.

<Production of Block Copolymer> In a cyclohexane solvent, n-butyllithium was used as an initiator, THF was used as a randomizing agent, and styrene and butadiene were used as monomers to produce block copolymers A to J in Table 1. . The molecular weight of the block copolymer was adjusted by the addition amount of the initiator, and the block ratio was adjusted by the addition amount of the randomizing agent.

[0038]

[Table 1]

<Vinyl Aromatic Hydrocarbon-Based Polymer> The following vinyl aromatic hydrocarbon-based polymers were used in the present invention. i. Polystyrene (a) [Denka Styrol HRM-5 manufactured by Denki Kagaku Kogyo KK]. ii. Experimental Example 1 Methyl methacrylate-styrene copolymer (II). Pure water 70.
After adding 4 kg and 300 g of tricalcium phosphate and stirring, styrene 64.8 kg and methyl methacrylate 1
5.2 Kg and 267.2 g of benzoyl peroxide were added, sealed, and reacted at 100 ° C. for 6 hours. After cooling this, it was neutralized, dehydrated and dried to obtain a polymer b. The number average molecular weight was 80,000. iii. Experimental example 2. N-Butyl acrylate-styrene copolymer (c). In Experimental Example 1, styrene was added at 76.8k
g, and n-butyl acrylate were charged in the same manner as in Experimental Example 1 except that 3.2 kg was charged to obtain a polymer (c). The number average molecular weight was 142,000. iv. Rubber modified impact resistant styrene resin (d) (HIPS)
[HI-S2 manufactured by Denki Kagaku Kogyo KK]. Table 2 shows a list of the above vinyl aromatic hydrocarbon polymers a to d.

[0040]

[Table 2]

Examples 1 to 10 The polymers shown in Table 2 were used as the vinyl aromatic hydrocarbon polymer, and after mixing with a Henschel mixer according to the formulations shown in Tables 3 and 4, the composition was obtained by melting and pelletizing with an extruder. Was manufactured. The silica used had a particle size of 6 μm, and the microcrystalline wax used had a melting point of 90 ° C. afterwards,
These compositions were extruded and stretched by the tubular method (setting conditions length: 1.2 times, width: 2.2 times, stretching temperature: 90 times).
C.) to obtain a heat-shrinkable tube. The physical properties of the tube are also shown in Tables 3 and 4. From these tables, it can be seen that the heat-shrinkable tube of the present invention has good openability, lubricity, shrinkability (shrinkage rate, shrinkage rate), and finishability. or,
Dry batteries using the tubes of Examples 1 to 10 at 45 ° C.
The battery was stored for 3 months, but no abnormalities occurred in the dry cell.

[0042]

[Table 3]

[0043]

[Table 4]

Comparative Examples 1 to 12 Block copolymer compositions and tubes were prepared in the same manner as in Examples 1 to 10, and their physical properties are shown in Tables 5 and 6. Although all of Comparative Examples 1 to 5 had good shrinkability, Comparative Example 1 did not contain an inorganic filler and a lubricant, Comparative Examples 2 to 4 did not contain a lubricant, and Comparative Example 5 did not contain an inorganic filler. Therefore, the openability and the slipperiness were very poor. The tube properties of Comparative Examples 6, 7 and 11 were inferior. Comparative Examples 8 to 10 and 12 had good openability and lubricity, but the structure of the block copolymer was other than that of the present invention, or the vinyl aromatic hydrocarbon had a high block ratio, so that the shrinkability and the finish were good. The sex was inferior.

[0045]

[Table 5]

[0046]

[Table 6]

The physical properties were measured by the following methods. However, the openness was determined by the adhesive strength method of the cut surface. (1) Glass transition temperature: Vibron DDV-II manufactured by Toyo Baldwin Co., Ltd. was used and measured at a vibration frequency of 11 Hz, which was taken as the peak temperature of the main dispersion of loss elastic modulus. (2) Adhesive strength: A tube (for example, a diameter of 25 mm) formed by a tubular method is folded with a nip roll and then cut into a length of 50 mm. Next, the cut-out tube is cut off from the folds of both ears by 5 mm. Furthermore, open the tube gently with one end in the width direction stuck (it is stuck due to the adhesive on the cut surface), pull both ends at 16 cm / min, and the maximum per cm when the tube separates The value is measured as the adhesive strength. As a result, when the adhesive strength was 40 g / cm or less, preferably 30 g / cm or less, the openability in the battery manufacturing apparatus was good, but when it exceeded 40 g / cm, the openability was not good.

(3) Coefficient of static friction: At room temperature, a 10 cm × 6.4 cm film was placed on a thread of a friction measuring machine (AN type) manufactured by Toyo Seiki Seisakusho Co., Ltd., and 28 c was placed on an inclined plate.
After setting m × 10 cm film, friction angle X
(°) is measured, and the value of tanX is set as the static friction coefficient,
Those of 0.35 or less were accepted. (4) Heat shrinkage rate: The tube was immersed in hot water at 85 ° C. for 5 seconds and calculated by the following formula.

[0049]

[Equation 1] L ₁ : Length before shrinking L ₂ : Length after shrinking (5) Finishing property: Folding diameter 41 mm, cut length 57 m
After the m-tube was coated on the C-cell, heat-shrinking at 85 ° C. was evaluated. A: Good B: Edges do not stick to each other and stand a little or the coating position shifts a little C: The phenomenon of B is severe

[0050]

The heat-shrinkable tube for a dry battery of the present invention is
It has excellent openability, lubricity, shrinkage, and liquid leakage prevention properties, so it can be used in extremely high-speed dry cell manufacturing equipment, and batteries covered with this tube have good finish and liquid leakage prevention. is there.

Continuation of front page (51) Int.Cl. ⁶ Identification number Office reference number FI Technical display location C08L 25/02 LEF C08L 25/02 LEF 53/02 LLV 53/02 LLV LLW LLW LLY LLY 91/06 LSJ 91 / 06 LSJ H01M 2/02 H01M 2/02 C // B29K 25:00 96:04 B29L 23:00 (72) Inventor Yasuo Yamagishi 660 Shiniemachi, Sakai City, Osaka Prefecture Sakai Chemical Industry Co., Ltd.

Claims (3)

[Claims] 1. A heat-shrinkable tube for a battery, comprising a block copolymer composition containing the following (a), (b), (c) and (d). (A) The weight ratio of vinyl aromatic hydrocarbon to conjugated diene is 6
0/40 to 90/10 and at least a general structural formula of-(SB) _n- (S is a vinyl aromatic hydrocarbon polymer block, B is a random aromatic vinyl hydrocarbon and a conjugated diene. Copolymerization part, n is an integer of 2 or more)
A block copolymer having a block represented by: 5
0-100 parts by weight. (B) Vinyl aromatic hydrocarbon polymer: 0 to 50 parts by weight. However, the total of (a) and (b) is 100 parts by weight. (C) Inorganic filler: 0.01 to 50 parts by weight based on 100 parts by weight of the total of (a) and (b). (D) Lubricant: 0.01 to 15 parts by weight based on 100 parts by weight of the total of (a) and (b). 2. When immersed in hot water at 85 ° C. for 5 seconds,
The heat-shrinkable tube for a battery according to claim 1, wherein the shrinkage rate is a longitudinal shrinkage rate of 5% or more in the length direction of the tube, and a lateral shrinkage rate of 40% or more in the width direction. 3. The adhesive strength of the cut surface of the tube is 40 g / c.
The heat-shrinkable tube for a battery according to claim 2, wherein the coefficient of static friction on the inner surface of the tube is 0.30 or less.