JP5133289B2 - Heat shrinkable film - Google Patents

Description

  The present invention relates to a heat shrinkable film.

Block copolymer made of vinyl aromatic hydrocarbon and conjugated diene, which has a relatively high vinyl aromatic hydrocarbon content, is injection-molded by taking advantage of its transparency and impact resistance. It is used for applications such as extrusion molding of sheets and films.
In particular, heat-shrinkable films using block copolymer resins composed of vinyl aromatic hydrocarbons and conjugated dienes are used for residual monomers such as vinyl chloride resins, plasticizer residues, and generation of hydrogen chloride during incineration. Since there is no problem, it is used for food packaging, cap seals, labels, etc.
Properties required for such a heat-shrinkable film include natural shrinkage, low-temperature shrinkage, transparency, mechanical strength, suitability for packaging machinery, etc. Various studies have been made to obtain this.

Patent Document 1 discloses a resin composition in which a specific partially hydrogenated block copolymer is added to a styrene resin and an olefin resin that are excellent in heat resistance and oil resistance and excellent in tensile elongation characteristics.
Patent Document 2 is excellent in solvent resistance, natural shrinkage, low temperature shrinkage, rigidity, etc., excellent in property balance such as blocking resistance, hot water fusion resistance, low temperature elongation and impact resistance, and is caused by gel. A hydrogenated copolymer having a specific structure for obtaining a heat-shrinkable film with little fish eye (FE) is disclosed.
In Patent Document 3, solvent resistance, natural shrinkage, low temperature shrinkage, rigidity, transparency, elongation, etc. suitable for a sheet film and a heat shrinkable film excellent in solvent resistance, rigidity, elongation and transparency are disclosed. Hydrogenated block copolymer having a specific storage elastic modulus (E ′) and loss elastic modulus (E ″), comprising a hydrogenated block copolymer having a specific structure and a polyolefin-based polymer excellent in physical property balance A composition is disclosed.
Patent Document 4 discloses a hydrogenated block copolymer having a specific structure excellent in a balance of physical properties suitable for a sheet and a heat-shrinkable film excellent in solvent resistance, rigidity, elongation and transparency, and a vinyl aromatic hydrocarbon heavy polymer. A composition with coalescence is disclosed.
In Patent Document 5, as a heat-shrinkable film excellent in high transparency and gloss, excellent low-temperature shrinkability and printability, a layer composed of an olefin resin and an adhesive resin is used as an intermediate layer, and a specific rubber-like elastic dispersion A laminate having a styrenic resin as a front surface layer and a back surface layer is disclosed.
Patent Document 6 describes a heat-shrinkable film having excellent printability and dimensional stability and having a specific gravity of less than 0.960, and a propylene-based resin and a petroleum-based resin between a front surface layer and a back surface layer made of a styrene resin. And a laminated body provided with an intermediate layer made of an adhesive resin.

JP 2001-240713 A JP 2006-117879 A JP 2007-39662 A International Publication No. 2006/109743 JP 2001-58377 A JP 2001-301102 A

  However, the heat-shrinkable film comprising a hydrogenated block copolymer comprising a vinyl aromatic hydrocarbon and a conjugated diene, or a composition containing them, disclosed in the above prior art, has a natural shrinkage and a low-temperature shrinkage. In addition, the balance of physical properties such as rigidity, especially the retention of low-temperature elongation after printing and the characteristics of low shrinkage stress are still not sufficient, and these documents do not suggest how to improve them. .

  Therefore, in the present invention, in view of the above-described problems of the prior art, it has excellent physical property balance such as natural shrinkage, low temperature shrinkage, and rigidity, and particularly retains low temperature elongation after printing and heat shrinkability that exhibits low shrinkage stress. Provide film.

As a result of intensive studies on the above problems, the present inventors have found that a block copolymer hydrogenated product (I) having a specific structure with a vinyl aromatic hydrocarbon content of 55 to 85% by mass and a vinyl aromatic carbonization. Heat shrinkage comprising a composition containing a block copolymer having a specific structure with a hydrogen content of more than 85% by mass and less than 95% by mass or a hydrogenated product (II) thereof and a predetermined olefinic resin (III) As a result, it was found that the film can achieve the above-mentioned purpose, and the present invention has been completed.
That is, the present invention is as follows.

[1]
Block copolymer hydrogenated product (I). 5 to 40 wt%,
Block copolymer (II) 39 to 90% by mass,
Olefin resin (III) 5 to 25 % by mass,
Comprising a composition containing
The block copolymer hydrogenated product (I) is a hydrogenated product of a block copolymer composed of a vinyl aromatic hydrocarbon and a conjugated diene, and the vinyl aromatic hydrocarbon content is 55 to 80 % by mass. The block ratio of the vinyl aromatic hydrocarbon polymer contained in the polymer hydrogenated product (I) is 50 to 95% by mass, and the total vinyl aromatic hydrocarbon in the block copolymer hydrogenated product (I) The number average molecular weight of the polymer block is from 50,000 to 60,000, and at least one peak temperature of the function tan δ of dynamic viscoelasticity measurement is present at −40 ° C. or lower, and the vinyl aromatic hydrocarbon and the conjugated diene The hydrogenation rate of the double bond of the conjugated diene unit in the block copolymer consisting of is 10% or more and less than 50%,
The block copolymer (II) is a block copolymer comprising a vinyl aromatic hydrocarbon and a conjugated diene, a vinyl aromatic hydrocarbon content of less than 95 wt% than 85 wt%, said block copolymer and vinyl aromatic hydrocarbon polymer block ratio of contained in the polymer (II) is a 20 to 95 wt%, the number of total vinyl aromatic hydrocarbon polymer block in the block copolymer (II) The average molecular weight is between 50,000 and 80,000, and there is at least one peak temperature of the function tan δ of the dynamic viscoelasticity measurement at 60 to 110 ° C. A heat-shrinkable film having a content of 0.5 to 10% by mass is provided.

[2] The vinyl aromatic hydrocarbon content in the block copolymer hydrogenated product (I) is 58 to 80% by mass, and the vinyl aromatic hydrocarbon contained in the block copolymer hydrogenated product (I). The block ratio of the polymer is 55 to 90% by mass, and the number average molecular weight of the all vinyl aromatic hydrocarbon polymer block in the block copolymer hydrogenated product (I) is from 50,000 to 50,000. A heat-shrinkable film according to the above [1] is provided.

[3] The block copolymer (II) has a vinyl aromatic hydrocarbon content of 87 to 93% by mass, and is a block of the vinyl aromatic hydrocarbon polymer contained in the block copolymer (II). The rate is 30 to 85% by mass, and the number average molecular weight of the all vinyl aromatic hydrocarbon polymer block in the block copolymer (II) is 50,000 to 60,000. The heat-shrinkable film according to the above [1] or [2], wherein at least one peak temperature of the function tan δ exists at 70 to 105 ° C.

[4] The heat-shrinkable film according to any one of [1] to [3], wherein the content of the hydrogenated conjugated diene unit in the composition is 0.8 to 9% by mass. provide.

[5] The heat-shrinkable film according to any one of [1] to [4], wherein the composition further contains the following polymer (IV).
Here, the polymer (IV) is at least one polymer selected from the group consisting of the following (i) to (iv).
(I): a block copolymer comprising a vinyl aromatic hydrocarbon and a conjugated diene different from the components (I) and (II) or a hydrogenated product thereof.
(Ii) A copolymer comprising a vinyl aromatic hydrocarbon and an aliphatic unsaturated carboxylic acid derivative.
(Iii) Vinyl aromatic hydrocarbon polymer.
(Iv) A rubber-modified styrenic polymer.

[6] The heat shrinkage according to [5], comprising a composition containing a total of 60 to 99.9% by mass of (I) to (III) and 0.1 to 40 % by mass of (IV). Provide a protective film.

[7] A lubricant containing at least one selected from the group consisting of fatty acid amides, paraffins, hydrocarbon resins, and fatty acids, with respect to a total of 100 parts by mass of (I), (II), and (III). The heat-shrinkable film according to any one of [1] to [4], further containing 0.01 to 5 parts by mass.

[8] A lubricant containing at least one selected from the group consisting of fatty acid amides, paraffins, hydrocarbon resins, and fatty acids, and a total of 100 masses of (I), (II), (III), and (IV). The heat-shrinkable film according to [5] or [6], which is contained in an amount of 0.01 to 5 parts by mass with respect to parts.

[9] At least one selected from the group consisting of benzophenone ultraviolet absorbers, benzotriazole ultraviolet absorbers, and hindered amine light stabilizers, a total of 100 masses of the components (I), (II) and (III). The heat-shrinkable film according to any one of [1] to [4] and [7], which is contained in an amount of 0.01 to 3 parts by mass with respect to parts.

[10] At least one selected from the group consisting of benzophenone-based UV absorbers, benzotriazole-based UV absorbers, and hindered amine light stabilizers is used as the component (I), (II), (III) and (IV The heat-shrinkable film according to any one of [5], [6], and [8], which is contained in an amount of 0.01 to 3 parts by mass with respect to 100 parts by mass in total.

[11] A multilayer film comprising the heat-shrinkable film according to any one of [1] to [10] is provided.

  According to the present invention, it is possible to obtain a heat-shrinkable film that is excellent in the balance of physical properties such as natural shrinkage, low-temperature shrinkage, and rigidity, and that is particularly excellent in maintaining low-temperature elongation and low shrinkage stress after printing.

  Hereinafter, although the form (henceforth this embodiment) for carrying out the present invention is explained, the present invention is not limited to the form shown below.

[Heat shrinkable film]
The heat-shrinkable film of this embodiment comprises a block copolymer hydrogenated product (I) 5 to 90% by mass, a block copolymer or hydrogenated product (II) 5 to 90% by mass, and an olefin resin (III). It consists of a composition containing 5-90 mass%.

(Block copolymer water additive (I): component (I))
The block copolymer hydrogenated product (I) is a hydrogenated product of a block copolymer comprising a vinyl aromatic hydrocarbon and a conjugated diene.
The vinyl aromatic hydrocarbon content is 55 to 85 mass%, preferably 58 to 80 mass%, more preferably 60 to 75 mass%. When the vinyl aromatic hydrocarbon content is in the range of 55 to 85% by mass, a heat-shrinkable film having an excellent balance between rigidity and elongation can be obtained.
The block ratio of the vinyl aromatic hydrocarbon polymer contained in the block copolymer hydrogenated product (I) is 50 to 95% by mass. Preferably it is 55-90 mass%, More preferably, it is 60-90 mass%. When the block ratio of the vinyl aromatic hydrocarbon polymer is in the range of 50 to 95% by mass, a heat-shrinkable film having a practically sufficient rigidity and excellent in maintaining low-temperature elongation after printing can be obtained.

The block ratio of the vinyl aromatic hydrocarbon polymer is determined by the weight of the random copolymer chain composed of the vinyl aromatic hydrocarbon and the conjugated diene in the block copolymer before hydrogenation of the component (I) and the vinyl aromatic. It can adjust with content (mass%) of hydrocarbon.
The block rate decreases as the amount of vinyl aromatic hydrocarbon in the random copolymer chain increases, and the block rate can increase as the amount decreases.
The block ratio of the vinyl aromatic hydrocarbon polymer is determined by a method in which the block copolymer before hydrogenation of the component (I) is oxidatively decomposed with tertiary butyl hydroperoxide using osmium tetroxide as a catalyst (oxidative decomposition method: I. M. KOLTHOFF, et al., J. Polym. Sci. 1, 429 (1946)).
Using the vinyl aromatic hydrocarbon polymer block component obtained by this method (however, the vinyl aromatic hydrocarbon polymer component having an average degree of polymerization of about 30 or less is excluded), it is obtained from the following formula.
Block ratio (mass%) = (weight of vinyl aromatic hydrocarbon polymer in block copolymer / weight of block polymer chain / total weight of vinyl aromatic hydrocarbon in block copolymer) × 100
In addition, by the above oxidative decomposition method, “the weight of the vinyl aromatic hydrocarbon polymer block polymer chain in the block copolymer” is determined, and “the total weight of the vinyl aromatic hydrocarbon in the block copolymer” is: It can be determined from the charge ratio at the time of polymerization or by analysis such as NMR.

The number average molecular weight of the all-vinyl aromatic hydrocarbon polymer block of the component (I) is from 50,000 to 60,000. Preferably it is 50,000 to 50,000, more preferably 7,000 to 45,000.
When the number average molecular weight of the total vinyl aromatic hydrocarbon polymer block is in the range of 50,000 to 60,000, the final heat shrinkable film has excellent low shrinkage stress and low temperature shrinkability. Become.
The number average molecular weight of the total vinyl aromatic hydrocarbon polymer block can be adjusted by the weight of the vinyl aromatic hydrocarbon polymer block or the molecular weight of the block copolymer.
By increasing the weight of the vinyl aromatic hydrocarbon polymer block or increasing the molecular weight of the block copolymer, the number average molecular weight of the total vinyl aromatic hydrocarbon polymer block becomes a high molecular weight.

The number average molecular weight of the total vinyl aromatic hydrocarbon polymer block was determined by gel permeation chromatography using the same vinyl aromatic hydrocarbon polymer block components as those used for quantification of the block ratio obtained by the oxidative decomposition method described above ( GPC) to specify and calculate.
The molecular weight is obtained by using a monodisperse polystyrene for gel permeation chromatography (GPC) and preparing a calibration curve between the peak count number and the number average molecular weight of the monodisperse polystyrene by GPC. (For example, “Gel Chromatography <Basics>” published by Kodansha).

The component (I) has at least one peak temperature of the function tan δ of dynamic viscoelasticity measurement at −40 ° C. or lower, preferably −50 ° C. or lower, more preferably −60 ° C. or lower.
When the peak temperature of the function tan δ of dynamic viscoelasticity measurement is in the range of −40 ° C. or less, a heat-shrinkable film excellent in maintaining low temperature elongation after printing can be obtained.
The function tan δ of the dynamic viscoelasticity measurement can be measured by, for example, a viscoelasticity measurement / analysis apparatus DVE · V4 manufactured by Rheology Co., Ltd. Specifically, it is obtained by measuring using a test piece having a thickness of 0.5 to 2 mm under conditions of a vibration frequency of 35 Hz and a temperature rising rate of 3 ° C./min.
The temperature showing the peak means a temperature at which the first derivative of the amount of change with respect to the temperature of the value of tan δ becomes zero.
The peak temperature of tan δ is the weight ratio of vinyl aromatic hydrocarbon to conjugated diene, the molecular weight of the block copolymer hydrogenated product, and the content of the vinyl aromatic hydrocarbon polymer block in the block copolymer hydrogenated product. The content of the short-chain vinyl aromatic hydrocarbon polymer portion having a vinyl aromatic hydrocarbon unit number in the range of 1 to 3 in the hydrogenated block copolymer is adjusted depending on the microstructure of the conjugated diene.
Specifically, at least one of the copolymer parts composed of the vinyl aromatic hydrocarbon and the conjugated diene has a vinyl aromatic hydrocarbon content of 50% by mass or less, the vinyl aromatic hydrocarbon and the conjugated diene, It is necessary to adjust the addition amount of the polar solvent to an optimum amount in order to minimize the chain of conjugated diene in the copolymer part.

The hydrogenation rate of the double bond of the conjugated diene unit in the component (I) is 10% or more and less than 50%. Preferably it is 15-45%, More preferably, it is the range of 20-40%.
When the hydrogenation rate of the double bond of the conjugated diene unit is in the range of 10% or more and less than 50%, a heat shrinkable film excellent in maintaining low temperature elongation after printing can be obtained.

The component (I) can be obtained by hydrogenating the block copolymer before hydrogenation.
The hydrogenation catalyst is not particularly limited and is conventionally known (1) A supported heterogeneous hydrogenation in which a metal such as Ni, Pt, Pd, or Ru is supported on carbon, silica, alumina, diatomaceous earth, or the like. A catalyst, (2) a so-called Ziegler-type hydrogenation catalyst using an organic acid salt such as Ni, Co, Fe, Cr or a transition metal salt such as acetylacetone salt and a reducing agent such as organic aluminum, (3) Ti, Ru, Examples thereof include homogeneous hydrogenation catalysts such as so-called organometallic complexes such as organometallic compounds such as Rh and Zr.
Specific examples of the hydrogenation catalyst include Japanese Patent Publication No. 42-8704, Japanese Patent Publication No. 43-6636, Japanese Patent Publication No. 63-4841, Japanese Patent Publication No. 1-337970, Japanese Patent Publication No. 1-53851, The hydrogenation catalyst described in Japanese Patent Publication No. 2-9041 can be used.
Preferred hydrogenation catalysts include mixtures with titanocene compounds and / or reducing organometallic compounds.
As the titanocene compound, compounds described in JP-A-8-109219 can be used. Specific examples include at least one ligand having a (substituted) cyclopentadienyl skeleton, indenyl skeleton or fluorenyl skeleton such as biscyclopentadienyl titanium dichloride and monopentamethylcyclopentadienyl titanium trichloride. Compounds.
Examples of the reducing organometallic compound include organic alkali metal compounds such as organolithium, organomagnesium compounds, organoaluminum compounds, organoboron compounds, and organozinc compounds.

The hydrogenation reaction is usually performed in a temperature range of 0 to 200 ° C, preferably 30 to 150 ° C.
The pressure of hydrogen used for the hydrogenation reaction is preferably 0.1 to 15 MPa, more preferably 0.2 to 10 MPa, and still more preferably 0.3 to 7 MPa.
The hydrogenation reaction time is usually 3 minutes to 10 hours, preferably 10 minutes to 5 hours.
The hydrogenation reaction may be a batch process, a continuous process, or a combination thereof.

The hydrogenation rate of the aromatic double bond based on the vinyl aromatic hydrocarbon of the component (I) is not particularly limited, but is preferably 50% or less, more preferably 30% or less, More preferably, it is 20% or less.
The hydrogenation rate can be measured by a nuclear magnetic resonance apparatus (NMR).

In the present invention, the microstructure (cis, trans, vinyl ratio) of the conjugated diene portion of the hydrogenated block copolymer (block copolymer water additive: component (I)) is determined by the use of a predetermined polar compound. Generally, the vinyl bond amount (block copolymer water additive: vinyl bond amount of component (I)) is 5 to 90%, preferably 10 to 80%, more preferably 15 to 75%. Can be set by range.
Examples of the polar compound include ethers such as tetrahydrofuran, diethylene glycol dimethyl ether and diethylene glycol dibutyl ether, amines such as triethylamine and tetramethylethylenediamine, thioethers, phosphines, phosphoramides, alkylbenzene sulfonates, alkoxides of potassium and sodium, etc. Is mentioned.
The vinyl bond amount is the total amount of 1,2-vinyl bond and 3,4-vinyl bond (however, when 1,3-butadiene is used as the conjugated diene, 1,2-vinyl bond amount) It is. The amount of vinyl bonds can be grasped by a nuclear magnetic resonance apparatus (NMR).

(Block copolymer or hydrogenated product (II): component (II))
The block copolymer or hydrogenated product (II) thereof is a block copolymer composed of a vinyl aromatic hydrocarbon and a conjugated diene or a hydrogenated product thereof.
The vinyl aromatic hydrocarbon content is more than 85% by mass and less than 95% by mass, preferably 87 to 93% by mass, more preferably 89 to 92% by mass.
When the vinyl aromatic hydrocarbon content is in the range of more than 85% by mass and less than 95% by mass, a heat-shrinkable film having an excellent balance between rigidity and natural shrinkage can be obtained.

The vinyl aromatic hydrocarbon polymer contained in the component (II) has a block ratio of 20 to 95% by mass, preferably 30 to 85% by mass, more preferably 35 to 80% by mass. To do.
When the block ratio of the vinyl aromatic hydrocarbon polymer contained in the component (II) is in the range of 20 to 95% by mass, a heat-shrinkable film excellent in rigidity and retention of low-temperature elongation after printing can be obtained. . About the adjustment and measurement method of a block rate, it can carry out by the method similar to the case of the component (I) mentioned above.

The number average molecular weight of the all-vinyl aromatic hydrocarbon polymer block of the component (II) is from 50,000 to 80,000, preferably from 50,000 to 60,000, more preferably from 7,000 to 50,000.
When the number average molecular weight of the total vinyl aromatic hydrocarbon polymer block of the component (II) is in the range of 50,000 to 80,000, a heat shrinkable film excellent in low shrinkage stress and low temperature shrinkability can be obtained. . The method for adjusting and measuring the number average molecular weight of the all-vinyl aromatic hydrocarbon polymer block can be performed by the same method as in the case of the component (I) described above.

The component (II) has at least one peak temperature of the function tan δ of dynamic viscoelasticity measurement at 60 to 110 ° C., preferably 70 to 105 ° C., more preferably 75 to 100 ° C.
When at least one peak temperature of the function tan δ of dynamic viscoelasticity measurement is in the range of 60 to 110 ° C., a heat shrinkable film excellent in low shrinkage stress and low temperature shrinkability can be obtained. The adjustment and measurement method of the peak temperature of the function tan δ of dynamic viscoelasticity measurement can be performed by the same method as in the case of the component (I) described above.

There is no restriction | limiting in particular about the hydrogenation rate of the double bond of the conjugated diene unit in the said component (II), It is 0 to 100%, Preferably it is 0 to 95%, More preferably, it is the range of 0 to 90%.
When the hydrogenation rate of the double bond of the conjugated diene unit in the component (II) is in the range of 0 to 50%, a heat-shrinkable film excellent in low-temperature shrinkage can be obtained, exceeding 50% and not more than 100% When it is within the range, a heat-shrinkable film having characteristics excellent in maintaining low-temperature elongation after printing can be obtained.
The method for hydrogenating the double bond of the conjugated diene unit in the component (II) and the method for measuring the hydrogenation rate can be performed by the same method as in the case of the component (I).

The component (I) and the component (II) include at least one segment composed of a vinyl aromatic hydrocarbon homopolymer and / or a copolymer composed of a vinyl aromatic hydrocarbon and a conjugated diene. And / or a conjugated diene homopolymer and / or at least one segment composed of a copolymer of vinyl aromatic hydrocarbon and conjugated diene.
The polymer structure before hydrogenation of the component (I) and the component (II) (including the block copolymer of the component (II)) is not particularly limited, but for example, the following general formulas (1) to (3) ) Or a hydrogenated product thereof, a radial block copolymer or a hydrogenated product thereof, or any mixture of these polymer structures.
(AB) n, A- (BA) n, B- (AB) n + 1 (1)
[(AB) k] m + 1-X, [(AB) kA] m + 1-X (2)
[(BA) k] m + 1-X, [(BA) kB] m + 1-X (3)
In the above formulas (1) to (3), the segment A is a vinyl aromatic hydrocarbon homopolymer and / or a copolymer composed of a vinyl aromatic hydrocarbon and a conjugated diene, and a segment B is a conjugated diene homopolymer and And / or a copolymer comprising a vinyl aromatic hydrocarbon and a conjugated diene.
X is a residue of a coupling agent such as silicon tetrachloride, tin tetrachloride, 1,3 bis (N, N-glycidylaminomethyl) cyclohexane, epoxidized soybean oil, or an initiator such as a polyfunctional organolithium compound. Indicates residue.
n, k, and m represent an integer of 1 or more, and are generally integers of 1 to 5.
Moreover, the structure of the polymer chain bonded to X may be the same or different.
In the radial block copolymer represented by the general formulas (1) to (3) or a hydrogenated product thereof, at least one A and / or B may be bonded to X.

The vinyl aromatic hydrocarbon in the copolymer of the vinyl aromatic hydrocarbon and the conjugated diene in the segment A and the segment B may be uniformly distributed, or may be distributed in a tapered shape (gradual decrease), A plurality of portions where vinyl aromatic hydrocarbons are uniformly distributed and / or portions where tapes are distributed may coexist in the segment.
Vinyl aromatic hydrocarbon content in segment A ({vinyl aromatic hydrocarbon in segment A / (vinyl aromatic hydrocarbon in segment A + conjugated diene)} × 100) and vinyl aromatic in segment B The relationship between the hydrocarbon content ({vinyl aromatic hydrocarbon in segment B / (vinyl aromatic hydrocarbon in segment B + conjugated diene)} × 100) It is preferable that the content is larger than the vinyl aromatic hydrocarbon content in the segment B. The difference in vinyl aromatic hydrocarbon content between segment A and segment B is preferably 5% by mass or more.

  In the present embodiment, the block copolymer before hydrogenation (including any of the block copolymer hydrogenated product (I) before hydrogenation and block copolymer (II); the same shall apply hereinafter). Is obtained, for example, by polymerizing a vinyl aromatic hydrocarbon and a conjugated diene (for example, anion living polymerization) in a hydrocarbon solvent using an organic alkali metal compound (for example, an organic lithium compound) or the like as a polymerization initiator. .

  Examples of the vinyl aromatic hydrocarbon constituting the block copolymer before hydrogenation include styrene, o-methylstyrene, p-methylstyrene, p-tert-butylstyrene, 1,3-dimethylstyrene, and α-methyl. Examples include styrene, vinyl naphthalene, vinyl anthracene, 1,1-diphenylethylene, N, N-dimethyl-p-aminoethyl styrene, N, N-diethyl-p-aminoethyl styrene, and the like. In particular, styrene is a common one. These may be used alone or in combination of two or more.

  As the conjugated diene constituting the block copolymer before hydrogenation, a diolefin having a pair of conjugated double bonds, such as 1,3-butadiene, 2-methyl-1,3-butadiene (isoprene), 2, Examples include 3-dimethyl-1,3-butadiene, 1,3-pentadiene, and 1,3-hexadiene. In particular, 1,3-butadiene, isoprene and the like can be mentioned as general ones. These may be used alone or in combination of two or more.

  Examples of the hydrocarbon solvent used for producing the block copolymer before hydrogenation include aliphatic hydrocarbons such as n-butane, isobutane, n-pentane, n-hexane, n-heptane, and n-octane. And cycloaliphatic hydrocarbons such as cyclopentane, methylcyclopentane, cyclohexane, methylcyclohexane, cycloheptane, and methylcycloheptane, and aromatic hydrocarbons such as benzene, toluene, xylene, and ethylbenzene. These may be used alone or in combination of two or more.

The polymerization initiator is generally an aliphatic hydrocarbon alkali metal compound, aromatic hydrocarbon alkali metal compound, or organic compound known to have anionic polymerization activity with respect to a conjugated diene and a vinyl aromatic compound. Examples thereof include amino alkali metal compounds.
Examples of the alkali metal include lithium, sodium, potassium, and the like. Suitable organic alkali metal compounds are aliphatic and aromatic hydrocarbon lithium compounds having 1 to 20 carbon atoms, one per one molecule. And a lithium compound, a dilithium compound containing a plurality of lithium atoms in one molecule, a trilithium compound, and a tetralithium compound.
Specifically, n-propyl lithium, n-butyl lithium, sec-butyl lithium, tert-butyl lithium, hexamethylene dilithium, butadienyl dilithium, isoprenyl dilithium, diisopropenylbenzene and sec-butyl lithium In addition, a reaction product of divinylbenzene, sec-butyllithium and a small amount of 1,3-butadiene can be used.
Furthermore, organic alkali metal compounds disclosed in US Pat. No. 5,708,092, British Patent 2,241,239, US Pat. No. 5,527,753, etc. can also be used. . These may be used alone or in combination of two or more.

In this embodiment, the polymerization temperature at the time of producing the block copolymer before hydrogenation is generally -10 ° C to 150 ° C, preferably 40 ° C to 120 ° C.
The time required for the polymerization varies depending on conditions, but is usually within 10 hours, particularly preferably 0.5 to 5 hours.
Further, it is desirable to replace the polymerization atmosphere with an inert gas such as nitrogen gas.
The polymerization pressure is not particularly limited as long as it is carried out within a range of pressure sufficient to maintain the monomer and solvent in the liquid layer within the above polymerization temperature range.
Furthermore, care must be taken not to mix impurities that inactivate the catalyst and living polymer, such as water, oxygen, and carbon dioxide, into the polymerization system.

(Olefin resin (III): component (III))
The olefin resin of component (III) is at least one polymer selected from polypropylene resin, polyethylene polymer, etc., for example, polyethylene, ethylene copolymer (ethylene-vinyl acetate copolymer, ethylene- Ethyl acrylate copolymer, ethylene-acrylic acid copolymer, ethylene-methyl methacrylate copolymer, ethylene-methacrylic acid copolymer, etc. or other copolymer derivatives of ethylene and unsaturated fatty acids, such ethylene Based ionomer resins, ethylene-α olefin copolymers, etc.), modified polymers having a carboxylic acid group added thereto, polybutene-1 copolymers, and the like. .
Particularly preferably, polypropylene resins (including random copolymers and those saturated with alicyclic saturated hydrocarbon resins, petroleum resins, tempen resins, rosins), high density polyethylene, linear-low density polyethylene ( L. LDPE), ultra-low density polyethylene, ionomer resin (for example, ethylene), and the like.

In the composition to be a heat shrinkable film in this embodiment, the weight ratio of the component (I), the component (II), and the component (III) is 100% of the composition as a whole. ) / Component (III), 5 to 90/5 to 90/5 to 90, preferably 10 to 80/10 to 80/10 to 80, more preferably 15 to 70/15 to 70/15 to 70. Range.
Moreover, the content of the hydrogenated conjugated diene unit in the composition to be the heat shrinkable film in the present embodiment is 0.5 to 10% by mass, preferably 0.8 to 9% by mass, more preferably Is 1-7 mass%.
As described above, when the weight ratio of the component (I), the component (II), and the component (III) is 100, the range is from 5 to 90/5 to 90/5 to 90, When the content of the hydrogenated conjugated diene unit is in the range of 0.5 to 10% by mass, the low temperature elongation and the retention of the low temperature elongation after printing are excellent.

(Polymer (IV): Component (IV))
The composition used as the heat-shrinkable film of this embodiment may be a composition in which the following polymer (IV) is blended.
The polymer (IV) is at least one selected from the following (i) to (iv).
(I) A block copolymer comprising a vinyl aromatic hydrocarbon and a conjugated diene, which are different from the component (I) and the component (II).
(Ii) A copolymer comprising a vinyl aromatic hydrocarbon and an aliphatic unsaturated carboxylic acid derivative.
(Iii) Vinyl aromatic hydrocarbon polymer.
(Iv) A rubber-modified styrenic polymer.

(I): Polymer structure of a block copolymer (hereinafter sometimes referred to as component (i)) composed of a vinyl aromatic hydrocarbon and a conjugated diene different from those of component (I) and component (II). (For hydrogenated products, the polymer structure before hydrogenation) has the following general formula:
(Ab-Bb) n, Ab- (Bb-Ab) n, Bb- (Ab-Bb) n + 1
(In the above formula, n is an integer of 1 or more, generally 1 to 5),
Or the following general formula:
[(Ab-Bb) k] m + 2-X, [(Ab-Bb) k-Ab] m + 2-X,
[(Bb-Ab) k] m + 2-X, [(Bb-Ab) k-Bb] m + 2-X
(In the above formula, Ab is a polymer block mainly composed of vinyl aromatic hydrocarbon, and Bb is a polymer mainly composed of conjugated diene. The boundary between Ab block and Bb block is not always clearly distinguished. X is a residue of a coupling agent such as silicon tetrachloride, tin tetrachloride, 1,3 bis (N, N-glycidylaminomethyl) cyclohexane, epoxidized soybean oil, or a polyfunctional organolithium compound. (Wherein k and m are integers of 1 to 5), or a mixture of arbitrary polymer structures of these block copolymers can be used. .

(I): The preferred vinyl aromatic hydrocarbon content of the block copolymer (component (i)) comprising a vinyl aromatic hydrocarbon and a conjugated diene different from those of the component (I) and the component (II) is 10 It is less than -95 mass%, More preferably, it is 20-90 mass%.
Regarding the molecular weight of the component (i), the number average molecular weight (polystyrene equivalent molecular weight) measured by gel permeation chromatography (GPC) is preferably 30,000 to 500,000, more preferably 50,000 to 500,000. 10,000 to 300,000 are more preferable.
The component (i) may be a mixture of a plurality of block copolymers having different molecular weights.
The number average molecular weight can be arbitrarily adjusted depending on the amount of catalyst used in the polymerization.

(Ii): What is a vinyl aromatic hydrocarbon of a copolymer composed of a vinyl aromatic hydrocarbon and an aliphatic unsaturated carboxylic acid derivative (hereinafter sometimes referred to as component (ii))? The styrene monomer mentioned above.
Aliphatic unsaturated carboxylic acid derivatives are C 1 -C 13, preferably C 2, such as acrylic acid, methyl acrylate, ethyl acrylate, propyl acrylate, butyl acrylate, pentyl acrylate and hexyl acrylate. ~ C13 ester derivatives of alcohol and acrylic acid, methacrylic acid, C1 -C13 carbon atoms, preferably C2 -C13, more preferably ester derivatives of C3 -C13 alcohol and methacrylic acid, α, β unsaturated dicarboxylic acids The acid is at least one selected from the group consisting of fumaric acid, itaconic acid, maleic acid and the like, or mono- or diester derivatives of these dicarboxylic acids and C2 to C13 alcohols.
Among the aliphatic unsaturated carboxylic acid derivatives, those mainly composed of esters such as ethyl acrylate, propyl acrylate, butyl acrylate, hexyl acrylate and octyl acrylate are preferable.

  As a method for producing the component (ii), a known method for producing a styrene resin, for example, a bulk polymerization method, a solution polymerization method, a suspension polymerization method, an emulsion polymerization method or the like can be applied. Component (ii): A copolymer comprising a vinyl aromatic hydrocarbon and an aliphatic unsaturated carboxylic acid derivative is a polymer having a weight average molecular weight of generally 50,000 to 500,000.

The component (ii) is particularly preferably a copolymer mainly composed of styrene and n-butyl acrylate. When the total amount of the component (ii) is 100% by mass, the total amount of n-butyl acrylate and styrene. Is preferably 50% by mass or more, more preferably an aliphatic unsaturated carboxylic acid ester-styrene copolymer in which the total amount of n-butyl acrylate and styrene is 60% by mass or more.
A heat-shrinkable film using an aliphatic unsaturated carboxylic acid ester-styrene copolymer mainly composed of n-butyl acrylate and styrene has good low-temperature shrinkability.

The (iii): vinyl aromatic hydrocarbon polymer (hereinafter sometimes referred to as component (iii)) is obtained by polymerizing a vinyl aromatic hydrocarbon or a monomer copolymerizable therewith ( However, the component (ii) is excluded).
The vinyl aromatic hydrocarbon mainly refers to a styrene monomer. Specific examples include styrene and α-alkyl-substituted styrenes such as α-methylstyrenes, nuclear alkyl-substituted styrenes, and nuclear halogen-substituted styrenes.
Examples of the monomer copolymerizable with the vinyl aromatic hydrocarbon include acrylonitrile and maleic anhydride.
Examples of the vinyl aromatic hydrocarbon polymer include polystyrene, styrene-α-methylstyrene copolymer, acrylonitrile-styrene copolymer, and styrene-maleic anhydride copolymer. Particularly preferred vinyl aromatic hydrocarbon polymers include polystyrene. These vinyl aromatic hydrocarbon polymers generally have a weight average molecular weight of 50,000 to 500,000. These vinyl aromatic hydrocarbon polymers may be used alone or in combination of two or more, and can be used as a rigidity improving agent.

The above (iv): rubber-modified styrenic polymer (hereinafter sometimes referred to as component (iv)) is obtained by polymerizing a mixture of a monomer and an elastomer copolymerizable with a vinyl aromatic hydrocarbon. It is done.
As the polymerization method, suspension polymerization, emulsion polymerization, bulk polymerization, bulk-suspension polymerization and the like are generally performed.
Examples of the monomer copolymerizable with the vinyl aromatic hydrocarbon include α-methylstyrene, acrylonitrile, acrylic acid ester, methacrylic acid ester, maleic anhydride and the like.
Examples of copolymerizable elastomers include natural rubber, synthetic isoprene rubber, butadiene rubber, styrene-butadiene rubber, and high styrene rubber.
These elastomers are generally 3 to 50 parts by mass with respect to 100 parts by mass of a monomer copolymerizable with a vinyl aromatic hydrocarbon, dissolved in the monomer copolymerizable with the vinyl aromatic hydrocarbon, or in a latex form. As emulsion polymerization, bulk polymerization, bulk-suspension polymerization and the like.
As the rubber-modified styrene polymer, an impact-resistant rubber-modified styrene polymer (HIPS) is particularly preferable.
The rubber-modified styrenic polymer can be used as an agent for improving rigidity, impact resistance and slipperiness.
As these rubber-modified styrenic polymers, polymers having a weight average molecular weight of generally 50,000 to 500,000 can be used.
The addition amount of the rubber-modified styrenic polymer is preferably 0.1 to 10 parts by mass with respect to 100 parts by mass in total of the components (I) to (III) in consideration of maintaining transparency.

The melt flow rate (MFR (temperature 200 ° C., load 5 kg) under the G condition) of the components (i) to (iv) described above is preferably 0.1 to 100 g / 10 min from the viewpoint of molding. 5 to 50 g / 10 min is more preferable, and 1 to 30 g / 10 min is more preferable.
The weight ratio of the component (IV) to the total of the components (I) to (III) is 50 to 99.9% by mass of the components (I) to (III), and the component (IV) is 0. 0.1 to 50% by mass is preferable, the total of the components (I) to (III) is 55 to 99.5% by mass, and the component (IV) is more preferably 0.5 to 45% by mass, More preferably, the total of the components (I) to (III) is 60 to 99% by mass and the component (IV) is 1 to 40% by mass.
A heat-shrinkable film having an excellent balance between rigidity and elongation when the total amount of the components (I) to (III) is 50 to 99.9% by mass and the component (IV) is in the range of 0.1 to 50% by mass. Is obtained.

(Other ingredients: lubricant)
The composition that becomes the heat-shrinkable film of this embodiment may contain a predetermined lubricant.
As the lubricant, for example, at least one selected from fatty acid amide, paraffin, hydrocarbon-based resin and fatty acid is 0.01 to 5 parts by mass, preferably 0.05 to 4 parts by mass with respect to 100 parts by mass of the composition. Part, more preferably 0.1 to 3 parts by mass, the blocking resistance of the heat-shrinkable film becomes good.
Examples of fatty acid amides include stearoamide, oleyl amide, erucyl amide, behen amide, mono- or bisamide of higher fatty acids, ethylene bis stearoamide, stearyl oleylamide, N-stearyl erucamide, and the like. These may be used alone or in combination of two or more.
Examples of the paraffin and hydrocarbon resin include paraffin wax, microcrystalline wax, liquid paraffin, paraffin synthetic wax, polyethylene wax, composite wax, montan wax, hydrocarbon wax, silicone oil, and the like. These may be used alone or in combination of two or more.
Examples of fatty acids include saturated fatty acids and unsaturated fatty acids. Specific examples include saturated fatty acids such as lauric acid, palmitic acid, stearic acid, behenic acid, and hydroxystearic acid, and unsaturated fatty acids such as oleic acid, erucic acid, and ricinoleic acid. These may be used alone or in combination of two or more.

(Other components: UV absorber, light stabilizer)
You may make the composition used as the heat-shrinkable film of this embodiment contain an ultraviolet absorber and a light stabilizer.
As the UV absorber and light stabilizer, at least one UV absorber and light stabilizer selected from benzophenone UV absorbers, benzotriazole UV absorbers, and hindered amine light stabilizers can be applied. Addition of 0.05 to 3 parts by weight, preferably 0.05 to 2.5 parts by weight, and more preferably 0.1 to 2 parts by weight with respect to 100 parts by weight of the composition, thereby improving the light resistance of the heat-shrinkable film. The effect of improving the property is obtained.
Examples of the benzophenone ultraviolet absorber include 2,4-dihydroxy-benzophenone, 2-hydroxy-4-methoxy-benzophenone, 2,2′-dihydroxy-4-methoxy-benzophenone, 2,2′-dihydroxy-4, 4'-dimethoxy benzophenone, 2-hydroxy-4-n-octoxy benzophenone, 2,2 ', 4,4'-tetrahydroxy benzophenone, 4-dodecyloxy-2-hydroxy benzophenone, 3,5-di- t-butyl-4-hydroxybenzoyl acid, n-hexadecyl ester, bis (5-benzoyl-4-hydroxy-2-methoxyphenyl) methane, 1,4-bis (4-benzoyl-3-hydroxyphenoxy) butane, 1,6-bis (4-benzoyl-3-hydroxyphenoxy) hex Emissions, and the like.
Examples of the benzotriazole ultraviolet absorber include 2- (2′-hydroxy-5′-methyl-phenyl) benzotriazole and 2- (2′-hydroxy-3 ′, 5′-di-t-butyl-phenyl). ) Benzotriazole, 2- (2′-hydroxy-3′-t-butyl-5′-methyl-phenyl) -5-chlorobenzotriazole, 2- (2′-hydroxy-3 ′, 5′-di-) t-butyl-phenyl) -5-chloro-benzotriazole, 2- (2′-hydroxy-5′-t-octylphenyl) benzotriazole, 2- (2′-hydroxy-3 ′, 5′-di-t -Amylphenyl) benzotriazole, 2- [2'-hydroxy-3 '-(3', 4 ', 5', 6'-tetrahydrophthalimidomethyl) -5'-methylphenyl] benzotriazole, 2-2 ' -Michile Bis [4- (1,1,3,3-tetramethylbutyl) -6- (2H-benzotriazol-2-yl) phenol], 2- [2-hydroxy-3,5-bis (α, α- Dimethylbenzyl) phenyl] -2H-benzotriazole, 2- (2-hydroxy-4-octyloxyphenyl) -2H-benzotriazole, 2- (2H-benzotriazol-2-yl) -4-methyl-6- ( 3,4,5,6-tetrahydrophthalimidylmethyl) phenol and the like.

Examples of the hindered amine light stabilizer include bis (2,2,6,6-tetramethyl-4-piperidyl) separate and bis (1,2,6,6,6, -pentmethyl-4-piperidyl). Sepacate, 1- [2- {3- (3,5-di-tert-butyl-4-hydroxydiphenyl) propionyloxy} ethyl] -4- {3- (3,5-di-tert-butyl-4- Hydroxydiphenyl) propionyloxy} -2,2,6,6-tetramethylpiperidine, 8-acetyl-3-dodecyl-7,7,9,9-tetramethyl-1,3,8-triasaspiro [4,5] Decane-2,4-dione, 4-benzoyloxy-2,2,6,6-tetramethylpiperidine, dimethyl-1- (2-hydroxyethyl) succinate) -4-hydroxy-2,2,6, - tetramethylpiperidine polycondensate and the like.
Examples of the hindered amine light stabilizer include poly [[6- (1,1,3,3-tetramethylbutyl) imino-1,3,5-triazine-2,4-diyl] [( 2,2,6,6-tetramethyl-4-piperidyl) imino] hexamethylene [[2,2,6,6-tetramethyl-4-piperidyl] imino]], poly [6-morpholino-s-triazine- 2,4-diyl] [(2,2,6,6-tetramethyl-4-piperidyl) imino] -hexamethylene [(2,2,6,6-tetramethyl-4-biperidyl) imino]], 2 -(3,5-di-tert-butyl-4-hydroxydibenzyl) -2-n-butylmalonate bis (1,2,2,6,6-pentamethyl-4-piperidyl), tetraxy (2,2 , 6,6-Tetramethyl-4-piperidyl ) 1,2,3,4-butanetetracarboxylate, tetraxy (1,2,2,6,6, -pentamethyl-4-piperidyl) 1,2,3,4, -butanetetracarboxylate, 1,2 , 3,4-butanetetracarbic acid, 1,2,2,6,6-pentamethyl-4-piperidinol and a condensate of tridecyl alcohol.
Furthermore, a condensate of 1,2,3,4-butanetetracarboxylic acid, 2,2,6,6-tetramethyl-4-piperidinol and tridecyl alcohol, 1,2,3,4-butanetetracarboxylic Acid, 1,2,2,6,6-pentamethyl-4-piperidinol and β, β, β, β-tetramethyl-3,9- (2,4,8,10-tetraoxaspiro [5,5] Undecane) condensate with diethanol, 1,2,3,4-butanetetracarboxylic acid, 2,2,6,6-tetramethyl-4-piperidinol and β, β, β, β-tetramethyl-3,9 -Condensation with (2,4,8,10-tetraoxaspiro [5,5] undecane) diethanol, N, N'-bis (3-aminopropyl) ethylenediamine · 2,4-bis [N-butyl- N- (1,2,2,6,6-Pendame Ru-4-piperidyl) amino] -6-chloro-1,3,5-triazine condensate, dibutylamine, 1,3,5-triazine, N, N-bis (2,2,6,6-tetramethyl -4-piperyl-1,6-hexamethylenediamine / N-2,2,6,6-tetramethyl-4-piperidyl) butylamine polycondensate, 1,2,2,6,6-tetramethyl-4 -Piperidyl-methacrylate, 2,2,6,6-tetramethyl-4-pipericyl-methacrylate and the like.

(Other ingredients: Stabilizer)
In the composition to be the heat-shrinkable film of the present embodiment, a predetermined stabilizer is added in an amount of 0.05 to 3 parts by mass, preferably 0.1 to 2 parts by mass with respect to 100 parts by mass of the composition. Thus, a gel suppressing effect can be obtained.
When the addition amount of the stabilizer is less than 0.05 parts by mass, the gel suppression effect cannot be obtained, and when it exceeds 3 parts by mass, the amount does not contribute to the gel suppression effect.
Examples of the stabilizer include a phenol-based stabilizer. Specifically, n-octadecyl 3- (3,5-di-t-butyl-4-hydroxyphenyl) propionate, 2-t-butyl-6- (3-t-butyl-2-hydroxy-5-methyl Benzyl) -4-methylphenyl acrylate, 2,4-bis [(octylthio) methyl] -o-cresol, tetrakis [methylene-3- (3,5-di-t-butyl-4-hydroxyphenyl) propionate] methane 1,3,5-trimethyl-2,4,6-tris (3,5-di-tert-butyl-4-hydroxybenzyl) benzene, 2,4-bis- (n-octylthio) -6- (4 -Hydroxy-3,5-di-t-butylanilino) -1,3,5-triazine and the like.
These may be used alone or in combination of two or more. Among these stabilizers, 2- [1- (2-hydroxy-3,5-di-t-pentylphenyl) ethyl] -4,6-di-t-pentylphenyl acrylate is particularly preferable.

(Other ingredients: additives)
Various additives can be added to the composition to be the heat-shrinkable film of the present embodiment according to the purpose.
Suitable additives include, for example, coumarone-indene resins, terpene resins, softeners such as oil, and plasticizers.
Various stabilizers, pigments, antiblocking agents, antistatic agents and the like can also be added.
Examples of the antiblocking agent and antistatic agent include fatty acid amide, ethylene bis-stearamide, sorbitan monostearate, saturated fatty acid ester of fatty acid alcohol, pentaerythritol fatty acid ester, and the like.
These are generally used in the range of 0.01 to 5% by mass, preferably 0.05 to 3% by mass with respect to the total of 100% by mass of the components (I) to (III).

[Method for producing composition to be heat-shrinkable film]
The manufacturing method of the composition used as the heat-shrinkable film of this embodiment is not specifically limited, It can manufacture with all the conventionally well-known compounding methods.
For example, an open roll, an intensive mixer, an internal mixer, a kneader, a continuous kneader with a twin-screw rotor, a melt-kneading method using a general mixer such as an extruder, a solvent after each component is dissolved or dispersed and mixed For example, a method of removing heat by heating is used.

[Method for producing heat-shrinkable film]
The heat-shrinkable film of this embodiment is a heat-shrinkable uniaxial or biaxially stretched film.
The material is extruded from a normal T die or an annular die into a flat shape or a tube shape at 150 to 250 ° C., preferably 170 to 220 ° C., and the resulting unstretched product is substantially uniaxially stretched or 2 It can be produced by a method of axial stretching, a method of producing a raw sheet before stretching as a first inflation step, and a method of obtaining a heat-shrinkable film again by a inflation method in a fluid as a second inflation step.

In the case of uniaxial stretching, in the case of a film or sheet, it is stretched in the extrusion direction with a calender roll or the like or in the direction perpendicular to the extrusion direction with a tenter or the like. Stretch.
In the case of biaxial stretching, in the case of a film or sheet, the extruded film or sheet is stretched in the longitudinal direction with a metal roll or the like and then stretched in the transverse direction with a tenter or the like. The tubes are stretched simultaneously or separately in the circumferential direction of the tube, that is, in a direction perpendicular to the tube axis.

In the manufacturing process of the heat-shrinkable film of this embodiment, the stretching temperature is preferably 60 to 130 ° C, more preferably 70 to 120 ° C, and further preferably 80 to 110 ° C.
Moreover, 1.5-8 times is preferable and, as for the draw ratio of a vertical direction and / or a horizontal direction, 2-6 times are more preferable.
When the stretching temperature is less than 60 ° C., it becomes difficult to produce a desired heat-shrinkable film by breaking at the time of stretching, and when it exceeds 130 ° C., the shrink property is deteriorated.
The draw ratio is selected within the above range so as to correspond to the shrinkage required by the intended use of the heat-shrinkable film. When the draw ratio is less than 1.5 times, the heat shrinkage rate is small and is not preferable for heat shrink packaging. On the other hand, when the draw ratio exceeds 8 times, it is not preferable from the viewpoint of securing stable productivity in the drawing process.
In the case of biaxial stretching, the stretching ratios in the longitudinal direction and the transverse direction may be the same or different.

  The heat-shrinkable film subjected to uniaxial stretching or biaxial stretching is subjected to heat treatment at 60 to 160 ° C., preferably 80 to 155 ° C. for a short time, for example, 3 to 60 seconds, preferably 10 to 40 seconds as necessary. And you may give the process which prevents the natural contraction in room temperature.

In order to use the heat-shrinkable film obtained as described above as a heat-shrinkable packaging material or a heat-shrinkable label material, the heat shrinkage rate at 80 ° C. in the stretching direction is 5 to 80%. It is preferably 10 to 75%, more preferably 15 to 70%.
When the heat shrinkage rate is within the above range, a heat shrinkable film having an excellent balance between the heat shrinkage rate and the natural shrinkage rate can be obtained.

  In the heat-shrinkable film of this embodiment, the heat shrinkage rate at 80 ° C. can be said to be a measure of low-temperature shrinkage. 80 ° C. heat shrinkage refers to a molded product when a uniaxially stretched or biaxially stretched film is immersed for 10 seconds in a heat medium such as 80 ° C. hot water, silicone oil, or glycerin that does not impair the properties of the molded product. The thermal shrinkage rate in each stretching direction.

In the heat-shrinkable film of the present embodiment, the natural shrinkage rate of the heat-shrinkable film itself is preferably 2.5% or less, more preferably 2.0% or less, in the range of the heat shrinkage rate. More preferably, it is 1.5% or less.
Here, the natural shrinkage rate of the heat-shrinkable film itself is a value calculated by an equation described later after leaving a heat-shrinkable film in the range of the heat shrinkage rate at 35 ° C. for 5 days.
Natural shrinkage (%) = (L2−L3) / L2 × 100
(L2 indicates the length before being left, and L3 indicates the length after being left.)

Furthermore, the uniaxially stretched or biaxially stretched film that is the heat-shrinkable film of the present embodiment preferably has a tensile elastic modulus in the stretching direction of 700 to 3000 MPa, and more preferably 1000 to 2500 MPa. Thereby, the function required as a heat shrink packaging material can be exhibited.
When the tensile elastic modulus in the stretching direction is less than 700 MPa, it is not preferable because it causes settling in the shrink wrapping process and normal wrapping cannot be performed.
Exceeding 3000 MPa is not preferable because the elongation of the film decreases.

  When the uniaxially stretched film or the biaxially stretched film that is the heat-shrinkable film of this embodiment is used as a heat-shrinkable packaging material, in order to achieve the target heat-shrinkage rate, it is 130 to 300 ° C., preferably 150 to 250. It is preferable to heat shrink at a temperature of 0 ° C. for several seconds to several minutes, preferably for 1 to 60 seconds.

The heat-shrinkable film of this embodiment may be a multilayer laminate of 2 to 5 layers, or 6 or more layers as necessary.
Specific examples of the usage form as the multilayer laminate include those disclosed in Japanese Patent Publication No. 3-5306.

  Even when the heat-shrinkable film of the present invention has a multilayer structure as described above, the heat-shrinkage rate at 80 ° C. in the stretching direction is preferably 5 to 80%. When the heat shrinkage is within this range, a heat shrinkable film excellent in the balance between the heat shrinkage and the natural shrinkage can be obtained.

The heat-shrinkable film of this embodiment can also be used as a multilayer film laminated with a film made of a predetermined material. In this case, the heat-shrinkable film of this embodiment may be used for the intermediate layer or both outer layers.
As such a multilayer film, layers other than the film layer which is a heat-shrinkable film are not particularly limited, and may be the heat-shrinkable film of the present embodiment having different constituent components and compositions, A heat-shrinkable film made of other materials may be used.
In addition, in the outer layer film in the case where the heat-shrinkable film of this embodiment is used as an intermediate layer, the Vicat softening temperature is preferably 3 to 15 ° C., preferably 5 to 12 ° C. higher than that of the intermediate layer.
10-300 micrometers is preferable, as for the thickness of the heat-shrinkable film and heat-shrinkable multilayer film of this embodiment, 20-200 micrometers is more preferable, and 30-100 micrometers is further more preferable.
The ratio of the thicknesses of both surface layers and the inner layer of the multilayer film is preferably 5/95 to 45/55, more preferably 10/90 to 35/65.

[Use]
The heat-shrinkable film in the present embodiment can be used for various uses such as packaging of fresh foods, confectionery, clothing, stationery, etc. by making use of the characteristics.
As a particularly preferred application, after printing letters and designs on a uniaxially stretched film, it is used by being closely adhered to the surface of a packaged article such as a plastic molded product, metal product, glass container, porcelain, etc. It can be used as a label material.
In particular, the heat-shrinkable film of the present embodiment is excellent in retention of low-temperature elongation after printing and low shrinkage stress. A material whose thermal expansion coefficient and water absorption are very different from the block copolymer of the present invention, for example, polyolefin resin such as metal, porcelain, glass, paper, polyethylene, polypropylene, polybutene, polymethacrylate resin, polycarbonate It can be suitably used as a heat-shrinkable label material for containers using at least one selected from resin, polyester resins such as polyethylene terephthalate and polybutylene terephthalate, and polyamide resins as constituent materials.
In addition, as a material constituting the plastic container in which the heat-shrinkable film in the present embodiment can be used, polystyrene, rubber-modified impact-resistant polystyrene (HIPS), styrene-butyl acrylate copolymer, styrene- Acrylonitrile copolymer, styrene-maleic anhydride copolymer, acrylonitrile-butadiene-styrene copolymer (ABS), methacrylate-butadiene-styrene copolymer (MBS), polyvinyl chloride resin, polyvinyl chloride Examples thereof include resins, phenol resins, urea resins, melamine resins, epoxy resins, unsaturated polyester resins, and silicone resins. These plastic containers may be a mixture of two or more resins or a laminate.

  Examples of the present invention and comparative examples will be specifically described below.

<Example of production of hydrogenated block copolymer (I)>
Block copolymer hydrogenated products A-1 to A-13 used in Examples and Comparative Examples were prepared by the following method.
The block copolymer before hydrogenation is produced in a cyclohexane solvent using n-butyllithium as a catalyst and tetramethylethylenediamine as a randomizing agent. The structure shown in Table 1 below, styrene content (% by mass), block ratio Then, a block copolymer hydrogenated product having a block styrene number average molecular weight, a tan δ peak temperature, and a predetermined hydrogenation rate was produced.
The styrene content was adjusted by the addition amount of styrene and butadiene.
The block ratio was adjusted by the styrene content and the structure of the block copolymer.
The block styrene number average molecular weight was adjusted by the weight of the styrene block or the molecular weight of the block copolymer.
The tan δ peak temperature was adjusted by the structure of the block copolymer.
In preparing the block copolymer hydrogenated product, the monomer diluted with cyclohexane to a concentration of 20% by mass was used.
The hydrogenation catalyst was charged with 1 liter of dried and purified cyclohexane in a nitrogen-substituted reaction vessel, 100 mmol of bis (η5-cyclopentadienyl) titanium dichloride was added, and 200 mmol of trimethylaluminum was added while stirring sufficiently. The hydrogenation catalyst which added the n-hexane solution containing and made it react at room temperature for about 3 days was used.
In addition, in “Structure of hydrogenated block copolymer” in Table 1 below and “Structure of block copolymer” in Table 2, A is a polystyrene part, B is a random copolymer part of styrene and butadiene, C represents a polybutadiene part, but the numbers given to these are different (for example, A1 and A2), or the numbered and unmarked (for example, B1 and B) are different from each other. It is not limited to the same thing, It has shown that a weight and molecular weight may mutually differ. However, they may be the same.

[Block copolymer hydrogenated product A-1]
Using an autoclave equipped with a stirrer, in a nitrogen gas atmosphere, 0.121 parts by mass of n-butyllithium in a cyclohexane solution containing 26 parts by mass of styrene and 0.3 times mol of tetramethylethylenediamine with respect to n-butyllithium Polymerization was carried out by continuously feeding at 65 ° C. for 30 minutes.
Next, polymerization was performed by continuously supplying a cyclohexane solution containing 7 parts by mass of styrene and 42 parts by mass of 1,3-butadiene at 65 ° C. for 65 minutes.
Next, polymerization was performed by continuously supplying a cyclohexane solution containing 25 parts by mass of styrene at 65 ° C. for 30 minutes.
Thereafter, 100 ppm of titanium as a hydrogenation catalyst was added per 100 parts by mass of the block copolymer, and a hydrogenation reaction was performed at a hydrogen pressure of 0.7 MPa and a temperature of 65 ° C.
Thereafter, methanol was added at a 1.0-fold mol to n-butyllithium, and then 2- [1- (2-hydroxy-3,5-di-t-pentylphenyl) ethyl] -4, 0.6 part by mass of 6-di-t-pentylphenyl acrylate was added to 100 parts by mass of the copolymer.
Thereafter, the solvent was removed to obtain a block copolymer hydrogenated product A-1.
The hydrogenation rate was adjusted by the amount of hydrogen.

[Block copolymer hydrogenated product A-2]
Using an autoclave equipped with a stirrer, in a nitrogen gas atmosphere, in a cyclohexane solution containing 35 parts by mass of styrene, 0.100 parts by mass of n-butyllithium and 0.3 times that of tetramethylethylenediamine with respect to n-butyllithium Mole was added and polymerization was carried out by continuously feeding at 65 ° C. for 40 minutes.
Next, polymerization was performed by continuously supplying a cyclohexane solution containing 3 parts by mass of styrene and 10 parts by mass of 1,3-butadiene at 65 ° C. for 20 minutes.
Next, polymerization was performed by continuously supplying a cyclohexane solution containing 6 parts by mass of styrene and 11 parts by mass of 1,3-butadiene at 65 ° C. for 25 minutes.
Next, polymerization was carried out by continuously supplying a cyclohexane solution containing 29 parts by mass of styrene at 65 ° C. for 35 minutes.
Thereafter, 100 ppm of titanium as a hydrogenation catalyst was added per 100 parts by mass of the block copolymer, and a hydrogenation reaction was performed at a hydrogen pressure of 0.7 MPa and a temperature of 65 ° C.
Thereafter, methanol was added at a 1.0-fold mol to n-butyllithium, and then 2- [1- (2-hydroxy-3,5-di-t-pentylphenyl) ethyl] -4, After adding 0.6 parts by mass of 6-di-t-pentylphenyl acrylate to 100 parts by mass of the copolymer, the solvent was removed to obtain hydrogenated block copolymer A-2.
The hydrogenation rate was adjusted by the amount of hydrogen.

[Block copolymer hydrogenated product A-3]
Using an autoclave equipped with a stirrer, in a nitrogen gas atmosphere, in a cyclohexane solution containing 30 parts by mass of styrene, 0.110 parts by mass of n-butyllithium and 0.3 times that of tetramethylethylenediamine with respect to n-butyllithium Mole was added and polymerization was carried out by continuously feeding at 65 ° C. for 35 minutes.
Next, polymerization was performed by continuously supplying a cyclohexane solution containing 12 parts by mass of styrene and 30 parts by mass of 1,3-butadiene at 65 ° C. for 55 minutes.
Next, polymerization was carried out by continuously supplying a cyclohexane solution containing 28 parts by mass of styrene at 65 ° C. for 35 minutes.
Thereafter, 100 ppm of titanium as a hydrogenation catalyst was added per 100 parts by mass of the block copolymer, and a hydrogenation reaction was performed at a hydrogen pressure of 0.7 MPa and a temperature of 65 ° C.
Thereafter, methanol was added at a 1.0-fold mol to n-butyllithium, and then 2- [1- (2-hydroxy-3,5-di-t-pentylphenyl) ethyl] -4, After adding 0.6 parts by mass of 6-di-t-pentylphenyl acrylate to 100 parts by mass of the copolymer, the solvent was removed to obtain a block copolymer hydrogenated product A-3.
The hydrogenation rate was adjusted by the amount of hydrogen.

[Block copolymer hydrogenated product A-4]
Using an autoclave equipped with a stirrer, in a nitrogen gas atmosphere, in a cyclohexane solution containing 33 parts by mass of styrene, 0.097 parts by mass of n-butyllithium and 0.3 times that of tetramethylethylenediamine with respect to n-butyllithium Mole was added and polymerization was carried out by continuously feeding at 65 ° C. for 40 minutes.
Next, polymerization was performed by continuously supplying a cyclohexane solution containing 5 parts by mass of styrene and 37 parts by mass of 1,3-butadiene at 65 ° C. for 50 minutes.
Next, polymerization was performed by continuously supplying a cyclohexane solution containing 25 parts by mass of styrene at 65 ° C. for 30 minutes.
Thereafter, 100 ppm of hydrogenation catalyst was added as titanium per 100 parts by mass of the block copolymer, and a hydrogenation reaction was performed at a hydrogen pressure of 0.7 MPa and a temperature of 65 ° C.
Thereafter, methanol was added at a 1.0-fold mol to n-butyllithium, and then 2- [1- (2-hydroxy-3,5-di-t-pentylphenyl) ethyl] -4, After adding 0.6 parts by mass of 6-di-t-pentylphenyl acrylate to 100 parts by mass of the copolymer, the solvent was removed to obtain a block copolymer hydrogenated product A-4.
The hydrogenation rate was adjusted by the amount of hydrogen.

[Block copolymer hydrogenated product A-5]
Using an autoclave equipped with a stirrer, in a nitrogen gas atmosphere, in a cyclohexane solution containing 30 parts by mass of styrene, 0.351 parts by mass of n-butyllithium and 0.2 times that of tetramethylethylenediamine with respect to n-butyllithium Mole was added and polymerization was carried out by continuously feeding at 65 ° C. for 35 minutes.
Next, polymerization was carried out by continuously supplying a cyclohexane solution containing 14 parts by mass of styrene and 21 parts by mass of 1,3-butadiene at 65 ° C. for 45 minutes.
Next, polymerization was carried out by continuously supplying a cyclohexane solution containing 24 parts by mass of styrene at 65 ° C. for 30 minutes.
Thereafter, after maintaining for 10 minutes, 1,3-bis (N, N-glycidylaminomethyl) cyclohexane was added to the autoclave in a 0.3-fold molar ratio with respect to n-butyllithium, held for 5 minutes, and then hydrogenated. The catalyst was added at 100 ppm as titanium per 100 parts by mass of the block copolymer, and a hydrogenation reaction was performed at a hydrogen pressure of 0.7 MPa and a temperature of 65 ° C.
Thereafter, methanol was added at a 1.0-fold mol to n-butyllithium, and then 2- [1- (2-hydroxy-3,5-di-t-pentylphenyl) ethyl] -4, After adding 0.6 parts by mass of 6-di-t-pentylphenyl acrylate to 100 parts by mass of the copolymer, the solvent was removed to obtain a block copolymer hydrogenated product A-5.
The hydrogenation rate was adjusted by the amount of hydrogen.

[Block copolymer hydrogenated product A-6]
Using an autoclave equipped with a stirrer, in a nitrogen gas atmosphere, in a cyclohexane solution containing 14 parts by mass of styrene, 0.116 parts by mass of n-butyllithium and 0.3 times that of tetramethylethylenediamine with respect to n-butyllithium Mole was added and polymerization was carried out by continuously feeding at 65 ° C. for 20 minutes.
Next, polymerization was performed by continuously supplying a cyclohexane solution containing 25 parts by mass of styrene and 47 parts by mass of 1,3-butadiene at 65 ° C. for 85 minutes.
Next, a cyclohexane solution containing 14 parts by mass of styrene was continuously supplied at 65 ° C. for 20 minutes for polymerization.
Thereafter, 100 ppm of hydrogenation catalyst was added as titanium per 100 parts by mass of the block copolymer, and a hydrogenation reaction was performed at a hydrogen pressure of 0.7 MPa and a temperature of 65 ° C.
Thereafter, methanol was added at a 1.0-fold mol to n-butyllithium, and then 2- [1- (2-hydroxy-3,5-di-t-pentylphenyl) ethyl] -4, After adding 0.6 parts by mass of 6-di-t-pentylphenyl acrylate to 100 parts by mass of the copolymer, the solvent was removed to obtain a block copolymer hydrogenated product A-6.
The hydrogenation rate was adjusted by the amount of hydrogen.

[Block copolymer hydrogenated product A-7]
Using an autoclave equipped with a stirrer, in a nitrogen gas atmosphere, 0.089 parts by mass of n-butyllithium in a cyclohexane solution containing 38 parts by mass of styrene and 0.3 times mol of tetramethylethylenediamine with respect to n-butyllithium Polymerization was carried out by continuously feeding at 65 ° C. for 40 minutes.
Next, polymerization was performed by continuously supplying a cyclohexane solution containing 9 parts by mass of styrene and 18 parts by mass of 1,3-butadiene at 65 ° C. for 40 minutes.
Next, polymerization was carried out by continuously supplying a cyclohexane solution containing 35 parts by mass of styrene at 65 ° C. for 40 minutes.
Thereafter, 100 ppm of hydrogenation catalyst was added as titanium per 100 parts by mass of the block copolymer, and a hydrogenation reaction was performed at a hydrogen pressure of 0.7 MPa and a temperature of 65 ° C.
Thereafter, methanol was added at a 1.0-fold mol to n-butyllithium, and then 2- [1- (2-hydroxy-3,5-di-t-pentylphenyl) ethyl] -4, After adding 0.6 parts by mass of 6-di-t-pentylphenyl acrylate to 100 parts by mass of the copolymer, the solvent was removed to obtain a block copolymer hydrogenated product A-7.
The hydrogenation rate was adjusted by the amount of hydrogen.

[Block copolymer hydrogenated product A-8]
Using an autoclave equipped with a stirrer, in a nitrogen gas atmosphere, 0.094 parts by mass of n-butyllithium and 0.3 times of tetramethylethylenediamine with respect to n-butyllithium were added to a cyclohexane solution containing 37 parts by mass of styrene. Mole was added and polymerization was carried out by continuously feeding at 65 ° C. for 40 minutes.
Next, polymerization was performed by continuously supplying a cyclohexane solution containing 1 part by mass of styrene and 27 parts by mass of 1,3-butadiene at 65 ° C. for 35 minutes.
Next, polymerization was carried out by continuously supplying a cyclohexane solution containing 35 parts by mass of styrene at 65 ° C. for 40 minutes.
Thereafter, 100 ppm of hydrogenation catalyst was added as titanium per 100 parts by mass of the block copolymer, and a hydrogenation reaction was performed at a hydrogen pressure of 0.7 MPa and a temperature of 65 ° C.
Thereafter, methanol was added at a 1.0-fold mol to n-butyllithium, and then 2- [1- (2-hydroxy-3,5-di-t-pentylphenyl) ethyl] -4, After adding 0.6 parts by mass of 6-di-t-pentylphenyl acrylate to 100 parts by mass of the copolymer, the solvent was removed to obtain hydrogenated block copolymer A-8.
The hydrogenation rate was adjusted by the amount of hydrogen.

[Block copolymer hydrogenated product A-9]
Using an autoclave equipped with a stirrer, in a nitrogen gas atmosphere, 0.090 parts by mass of n-butyllithium and 0.3 times of tetramethylethylenediamine with respect to n-butyllithium in a cyclohexane solution containing 15 parts by mass of styrene Mole was added and polymerization was carried out by continuously feeding at 65 ° C. for 20 minutes.
Next, polymerization was performed by continuously supplying a cyclohexane solution containing 34 parts by mass of styrene and 37 parts by mass of 1,3-butadiene at 65 ° C. for 85 minutes.
Next, a cyclohexane solution containing 14 parts by mass of styrene was continuously supplied at 65 ° C. for 20 minutes for polymerization.
Thereafter, 100 ppm of hydrogenation catalyst was added as titanium per 100 parts by mass of the block copolymer, and a hydrogenation reaction was performed at a hydrogen pressure of 0.7 MPa and a temperature of 65 ° C.
Thereafter, methanol was added at a 1.0-fold mol to n-butyllithium, and then 2- [1- (2-hydroxy-3,5-di-t-pentylphenyl) ethyl] -4, After adding 0.6 parts by mass of 6-di-t-pentylphenyl acrylate to 100 parts by mass of the copolymer, the solvent was removed to obtain a block copolymer hydrogenated product A-9.
The hydrogenation rate was adjusted by the amount of hydrogen.

[Block copolymer hydrogenated product A-10]
Using an autoclave equipped with a stirrer, in a nitrogen gas atmosphere, in a cyclohexane solution containing 5 parts by mass of styrene, 0.114 parts by mass of n-butyllithium and 0.3 times that of tetramethylethylenediamine with respect to n-butyllithium Mole was added and polymerization was carried out by continuously supplying at 65 ° C. for 10 minutes.
Next, polymerization was performed by continuously supplying a cyclohexane solution containing 20 parts by mass of styrene and 25 parts by mass of 1,3-butadiene at 65 ° C. for 55 minutes.
Next, polymerization was carried out by continuously supplying a cyclohexane solution containing 5 parts by mass of styrene at 65 ° C. for 10 minutes.
Next, polymerization was performed by continuously supplying a cyclohexane solution containing 20 parts by mass of styrene and 25 parts by mass of 1,3-butadiene at 65 ° C. for 55 minutes.
Next, polymerization was carried out by continuously supplying a cyclohexane solution containing 5 parts by mass of styrene at 65 ° C. for 10 minutes.
Thereafter, 100 ppm of hydrogenation catalyst was added as titanium per 100 parts by mass of the block copolymer, and a hydrogenation reaction was performed at a hydrogen pressure of 0.7 MPa and a temperature of 65 ° C.
Thereafter, methanol was added at a 1.0-fold mol to n-butyllithium, and then 2- [1- (2-hydroxy-3,5-di-t-pentylphenyl) ethyl] -4, After adding 0.6 parts by mass of 6-di-t-pentylphenyl acrylate to 100 parts by mass of the copolymer, the solvent was removed to obtain a block copolymer hydrogenated product A-10.
The hydrogenation rate was adjusted by the amount of hydrogen.

[Block copolymer hydrogenated product A-11]
Using an autoclave equipped with a stirrer, in a nitrogen gas atmosphere, in a cyclohexane solution containing 75 parts by mass of styrene, 0.077 parts by mass of n-butyllithium and 0.3 times that of tetramethylethylenediamine with respect to n-butyllithium Mole was added and polymerization was carried out by continuously supplying at 65 ° C. for 85 minutes.
Next, polymerization was performed by continuously supplying a cyclohexane solution containing 5 parts by mass of styrene and 8 parts by mass of 1,3-butadiene at 65 ° C. for 20 minutes.
Next, polymerization was performed by continuously supplying a cyclohexane solution containing 5 parts by mass of styrene and 7 parts by mass of 1,3-butadiene at 65 ° C. for 20 minutes.
Thereafter, 100 ppm of hydrogenation catalyst was added as titanium per 100 parts by mass of the block copolymer, and a hydrogenation reaction was performed at a hydrogen pressure of 0.7 MPa and a temperature of 65 ° C.
Thereafter, methanol was added at a 1.0-fold mol to n-butyllithium, and then 2- [1- (2-hydroxy-3,5-di-t-pentylphenyl) ethyl] -4, After adding 0.6 parts by mass of 6-di-t-pentylphenyl acrylate to 100 parts by mass of the copolymer, the solvent was removed to obtain a block copolymer hydrogenated product A-11.
The hydrogenation rate was adjusted by the amount of hydrogen.

[Block copolymer hydrogenated product A-12]
Using an autoclave equipped with a stirrer, in a nitrogen gas atmosphere, in a cyclohexane solution containing 30 parts by mass of styrene, 0.110 parts by mass of n-butyllithium and 0.3 times that of tetramethylethylenediamine with respect to n-butyllithium Mole was added and polymerization was carried out by continuously feeding at 65 ° C. for 40 minutes.
Next, polymerization was performed by continuously supplying a cyclohexane solution containing 12 parts by mass of styrene and 30 parts by mass of 1,3-butadiene at 65 ° C. for 50 minutes.
Next, polymerization was carried out by continuously supplying a cyclohexane solution containing 28 parts by mass of styrene at 65 ° C. for 40 minutes.
Thereafter, 100 ppm of hydrogenation catalyst was added as titanium per 100 parts by mass of the block copolymer, and a hydrogenation reaction was performed at a hydrogen pressure of 0.7 MPa and a temperature of 65 ° C.
Thereafter, methanol was added at a 1.0-fold mol to n-butyllithium, and then 2- [1- (2-hydroxy-3,5-di-t-pentylphenyl) ethyl] -4, After adding 0.6 parts by mass of 6-di-t-pentylphenyl acrylate to 100 parts by mass of the copolymer, the solvent was removed to obtain a block copolymer hydrogenated product A-12.
The hydrogenation rate was adjusted by the amount of hydrogen.

[Block copolymer A-13 (hydrogenation rate: 0%)]
Using an autoclave equipped with a stirrer, in a nitrogen gas atmosphere, 0.110 parts by mass of n-butyllithium and 0.3 times mol of tetramethylethylenediamine with respect to n-butyllithium in a cyclohexane solution containing 30 parts by mass of styrene Polymerization was carried out by continuously feeding at 65 ° C. for 40 minutes.
Next, polymerization was performed by continuously supplying a cyclohexane solution containing 12 parts by mass of styrene and 30 parts by mass of 1,3-butadiene at 65 ° C. for 50 minutes.
Next, polymerization was carried out by continuously supplying a cyclohexane solution containing 28 parts by mass of styrene at 65 ° C. for 40 minutes.
Thereafter, after holding for 10 minutes, methanol was added to the autoclave at a 1.0-fold molar ratio with respect to n-butyllithium to terminate the polymerization, and 2- [1- (2-hydroxy-3,5-di-oxide as a stabilizer. -T-pentylphenyl) ethyl] -4,6-di-t-pentylphenyl acrylate was added in an amount of 0.6 parts by mass based on 100 parts by mass of the copolymer.
Thereafter, the solvent was removed to obtain a block copolymer A-13.

<Example of production of block copolymer or hydrogenated product (II) thereof>
Block copolymers or hydrogenated products B-1 to B-11 used in Examples and Comparative Examples described later were prepared by the following method.
A block copolymer having the structure, styrene content (% by mass), block ratio, block styrene number average molecular weight, and tan δ peak temperature shown in Table 2 below was produced.
The styrene content was adjusted by adding styrene and butadiene.
The block ratio was adjusted by the styrene content and the structure of the block copolymer.
The block styrene number average molecular weight was adjusted by the weight of the styrene block or the molecular weight of the block copolymer.
The tan δ peak temperature was adjusted by the structure of the block copolymer.
In the preparation of the block copolymer, the monomer diluted with cyclohexane to a concentration of 20% by mass was used.

[Block copolymer B-1]
Using an autoclave equipped with a stirrer, in a nitrogen gas atmosphere, in a cyclohexane solution containing 3 parts by mass of 1,3-butadiene, 0.036 parts by mass of n-butyllithium and tetramethylethylenediamine with respect to n-butyllithium Polymerization was carried out by adding 0.3 mol and continuously feeding at 65 ° C. for 10 minutes.
Next, a cyclohexane solution containing 14 parts by mass of styrene was continuously supplied at 65 ° C. for 20 minutes for polymerization.
Next, polymerization was performed by continuously supplying a cyclohexane solution containing 59 parts by mass of styrene and 10 parts by mass of 1,3-butadiene at 65 ° C. for 80 minutes.
Next, a cyclohexane solution containing 14 parts by mass of styrene was continuously supplied at 65 ° C. for 20 minutes for polymerization.
Thereafter, after holding for 10 minutes, methanol was added to the autoclave at a 1.0-fold molar ratio with respect to n-butyllithium to terminate the polymerization, and 2- [1- (2-hydroxy-3,5-di-oxide as a stabilizer. -T-pentylphenyl) ethyl] -4,6-di-t-pentylphenyl acrylate was added in an amount of 0.6 parts by mass based on 100 parts by mass of the copolymer.
Thereafter, the solvent was removed to obtain a block copolymer B-1.

[Block copolymer B-2]
Using an autoclave equipped with a stirrer, in a nitrogen gas atmosphere, 0.033 parts by mass of n-butyllithium in a cyclohexane solution containing 25 parts by mass of styrene and 0.3 times mol of tetramethylethylenediamine with respect to n-butyllithium Polymerization was carried out by continuously feeding at 65 ° C. for 30 minutes.
Next, polymerization was performed by continuously supplying a cyclohexane solution containing 44 parts by mass of styrene and 7 parts by mass of 1,3-butadiene at 65 ° C. for 60 minutes.
Next, polymerization was carried out by continuously supplying a cyclohexane solution containing 24 parts by mass of styrene at 65 ° C. for 30 minutes.
Thereafter, after holding for 10 minutes, methanol was added to the autoclave at a 1.0-fold molar ratio with respect to n-butyllithium to terminate the polymerization, and 2- [1- (2-hydroxy-3,5-di-oxide as a stabilizer. -T-pentylphenyl) ethyl] -4,6-di-t-pentylphenyl acrylate was added in an amount of 0.6 parts by mass based on 100 parts by mass of the copolymer.
Thereafter, the solvent was removed to obtain a block copolymer B-2.

[Block copolymer B-3]
Using an autoclave equipped with a stirrer, in a nitrogen gas atmosphere, 0.035 parts by mass of n-butyllithium and 0.3 times mol of tetramethylethylenediamine with respect to n-butyllithium in a cyclohexane solution containing 16 parts by mass of styrene Polymerization was carried out by continuously feeding at 65 ° C. for 20 minutes.
Next, polymerization was carried out by continuously supplying a cyclohexane solution containing 20 parts by mass of styrene and 6 parts by mass of 1,3-butadiene at 65 ° C. for 35 minutes.
Next, polymerization was performed by continuously supplying a cyclohexane solution containing 36 parts by mass of styrene and 6 parts by mass of 1,3-butadiene at 65 ° C. for 50 minutes.
Next, polymerization was performed by continuously supplying a cyclohexane solution containing 16 parts by mass of styrene at 65 ° C. for 20 minutes.
Thereafter, after holding for 10 minutes, methanol was added to the autoclave at a 1.0-fold molar ratio with respect to n-butyllithium to terminate the polymerization, and 2- [1- (2-hydroxy-3,5-di-oxide as a stabilizer. -T-pentylphenyl) ethyl] -4,6-di-t-pentylphenyl acrylate was added in an amount of 0.6 parts by mass based on 100 parts by mass of the copolymer.
Thereafter, the solvent was removed to obtain a block copolymer B-3.

[Block copolymer B-4]
Using an autoclave equipped with a stirrer, in a nitrogen gas atmosphere, 0.113 parts by mass of n-butyllithium in a cyclohexane solution containing 20 parts by mass of styrene and 0.3 times mol of tetramethylethylenediamine with respect to n-butyllithium Polymerization was carried out by continuously feeding at 65 ° C. for 25 minutes.
Next, polymerization was performed by continuously supplying a cyclohexane solution containing 52 parts by mass of styrene and 10 parts by mass of 1,3-butadiene at 65 ° C. for 70 minutes.
Next, polymerization was performed by continuously supplying a cyclohexane solution containing 18 parts by mass of styrene at 65 ° C. for 25 minutes.
Thereafter, after holding for 10 minutes, 1,3-bis (N, N-glycidylaminomethyl) cyclohexane was added to the autoclave in a 0.3-fold molar ratio with respect to n-butyllithium, and then to n-butyllithium. Methanol was added at a 1.0-fold molar ratio, and 2- [1- (2-hydroxy-3,5-di-t-pentylphenyl) ethyl] -4,6-di-t-pentylphenyl acrylate was used as a stabilizer. 0.6 mass part was added with respect to 100 mass parts of polymers.
Thereafter, the solvent was removed to obtain a block copolymer B-4.

[Block copolymer B-5]
Using an autoclave equipped with a stirrer, in a nitrogen gas atmosphere, in a cyclohexane solution containing 12 parts by mass of styrene, 0.034 parts by mass of n-butyllithium and tetramethylethylenediamine were 0.2 times that of n-butyllithium. Mole was added and polymerization was carried out by continuously feeding at 65 ° C. for 20 minutes.
Next, polymerization was performed by continuously supplying a cyclohexane solution containing 59 parts by mass of styrene and 18 parts by mass of 1,3-butadiene at 65 ° C. for 85 minutes.
Next, a cyclohexane solution containing 11 parts by mass of styrene was continuously supplied at 65 ° C. for 15 minutes for polymerization.
Thereafter, after holding for 10 minutes, methanol was added to the autoclave at a 1.0-fold molar ratio with respect to n-butyllithium to terminate the polymerization, and 2- [1- (2-hydroxy-3,5-di-oxide as a stabilizer. -T-pentylphenyl) ethyl] -4,6-di-t-pentylphenyl acrylate was added in an amount of 0.6 parts by mass based on 100 parts by mass of the copolymer.
Thereafter, the solvent was removed to obtain a block copolymer B-5.

[Block copolymer B-6]
Using an autoclave equipped with a stirrer, in a nitrogen gas atmosphere, 0.033 parts by mass of n-butyllithium in a cyclohexane solution containing 36 parts by mass of styrene and 0.3 times mol of tetramethylethylenediamine with respect to n-butyllithium Polymerization was carried out by continuously feeding at 65 ° C. for 45 minutes.
Next, polymerization was performed by continuously supplying a cyclohexane solution containing 25 parts by mass of styrene and 3 parts by mass of 1,3-butadiene at 65 ° C. for 40 minutes.
Next, polymerization was carried out by continuously supplying a cyclohexane solution containing 36 parts by mass of styrene at 65 ° C. for 45 minutes.
Thereafter, after holding for 10 minutes, methanol was added to the autoclave at a 1.0-fold molar ratio with respect to n-butyllithium to terminate the polymerization, and 2- [1- (2-hydroxy-3,5-di-oxide as a stabilizer. -T-pentylphenyl) ethyl] -4,6-di-t-pentylphenyl acrylate was added in an amount of 0.6 parts by mass based on 100 parts by mass of the copolymer.
Thereafter, the solvent was removed to obtain a block copolymer B-6.

[Block copolymer B-7]
Using an autoclave equipped with a stirrer, in a nitrogen gas atmosphere, in a cyclohexane solution containing 4 parts by mass of styrene, 0.038 parts by mass of n-butyllithium and 0.3 times that of tetramethylethylenediamine with respect to n-butyllithium Mole was added and polymerization was carried out by continuously supplying at 65 ° C. for 10 minutes.
Next, polymerization was carried out by continuously supplying a cyclohexane solution containing 76 parts by mass of styrene and 15 parts by mass of 1,3-butadiene at 65 ° C. for 100 minutes.
Next, polymerization was carried out by continuously supplying a cyclohexane solution containing 5 parts by mass of styrene at 65 ° C. for 10 minutes.
Thereafter, after holding for 10 minutes, methanol was added to the autoclave at a 1.0-fold molar ratio with respect to n-butyllithium to terminate the polymerization, and 2- [1- (2-hydroxy-3,5-di-oxide as a stabilizer. -T-pentylphenyl) ethyl] -4,6-di-t-pentylphenyl acrylate was added in an amount of 0.6 parts by mass based on 100 parts by mass of the copolymer.
Thereafter, the solvent was removed to obtain a block copolymer B-7.

[Block copolymer B-8]
Using an autoclave equipped with a stirrer, in a nitrogen gas atmosphere, in a cyclohexane solution containing 46 parts by mass of styrene, 0.034 parts by mass of n-butyllithium and 0.3 times that of tetramethylethylenediamine with respect to n-butyllithium Mole was added and polymerization was carried out by continuously feeding at 65 ° C. for 55 minutes.
Next, polymerization was performed by continuously supplying a cyclohexane solution containing 3 parts by mass of styrene and 5 parts by mass of 1,3-butadiene at 65 ° C. for 15 minutes.
Next, polymerization was carried out by continuously supplying a cyclohexane solution containing 46 parts by mass of styrene at 65 ° C. for 55 minutes.
Thereafter, after holding for 10 minutes, methanol was added to the autoclave at a 1.0-fold molar ratio with respect to n-butyllithium to terminate the polymerization, and 2- [1- (2-hydroxy-3,5-di-oxide as a stabilizer. -T-pentylphenyl) ethyl] -4,6-di-t-pentylphenyl acrylate was added in an amount of 0.6 parts by mass based on 100 parts by mass of the copolymer.
Thereafter, the solvent was removed to obtain a block copolymer B-8.

[Block copolymer B-9]
Using an autoclave equipped with a stirrer, in a nitrogen gas atmosphere, in a cyclohexane solution containing 2 parts by mass of styrene, 0.038 parts by mass of n-butyllithium and 0.3 times that of tetramethylethylenediamine with respect to n-butyllithium Mole was added and polymerization was carried out by continuously supplying at 65 ° C. for 8 minutes.
Next, polymerization was performed by continuously supplying a cyclohexane solution containing 41 parts by mass of styrene and 6 parts by mass of 1,3-butadiene at 65 ° C. for 55 minutes.
Next, polymerization was carried out by continuously supplying a cyclohexane solution containing 2 parts by mass of styrene at 65 ° C. for 8 minutes.
Next, polymerization was performed by continuously supplying a cyclohexane solution containing 42 parts by mass of styrene and 5 parts by mass of 1,3-butadiene at 65 ° C. for 55 minutes.
Next, polymerization was carried out by continuously supplying a cyclohexane solution containing 2 parts by mass of styrene at 65 ° C. for 8 minutes. Thereafter, after holding for 10 minutes, methanol was added to the autoclave at a 1.0-fold molar ratio with respect to n-butyllithium to terminate the polymerization, and 2- [1- (2-hydroxy-3,5-di-oxide as a stabilizer. -T-pentylphenyl) ethyl] -4,6-di-t-pentylphenyl acrylate was added in an amount of 0.6 parts by mass based on 100 parts by mass of the copolymer.
Thereafter, the solvent was removed to obtain a block copolymer B-9.

[Block copolymer B-10]
Using an autoclave equipped with a stirrer, in a nitrogen gas atmosphere, in a cyclohexane solution containing 43 parts by mass of styrene, 0.033 parts by mass of n-butyllithium and 0.3 times that of tetramethylethylenediamine with respect to n-butyllithium Mole was added and polymerization was carried out by continuously feeding at 65 ° C. for 50 minutes.
Next, polymerization was performed by continuously supplying a cyclohexane solution containing 24 parts by mass of styrene and 6 parts by mass of 1,3-butadiene at 65 ° C. for 35 minutes.
Next, polymerization was performed by continuously supplying a cyclohexane solution containing 23 parts by mass of styrene and 6 parts by mass of 1,3-butadiene at 65 ° C. for 35 minutes.
Thereafter, after holding for 10 minutes, methanol was added to the autoclave at a 1.0-fold molar ratio with respect to n-butyllithium to terminate the polymerization, and 2- [1- (2-hydroxy-3,5-di-oxide as a stabilizer. -T-pentylphenyl) ethyl] -4,6-di-t-pentylphenyl acrylate was added in an amount of 0.6 parts by mass based on 100 parts by mass of the copolymer.
Thereafter, the solvent was removed to obtain a block copolymer B-10.

[Block Copolymer B-11]
Using an autoclave equipped with a stirrer, in a nitrogen gas atmosphere, in a cyclohexane solution containing 25 parts by mass of styrene, 0.035 parts by mass of n-butyllithium and 0.3% of tetramethylethylenediamine with respect to n-butyllithium were added. Double moles were added and polymerization was carried out by continuously feeding at 65 ° C. for 30 minutes.
Next, polymerization was performed by continuously supplying a cyclohexane solution containing 3 parts by mass of 1,3-butadiene at 65 ° C. for 7 minutes.
Next, polymerization was performed by continuously supplying a cyclohexane solution containing 32 parts by mass of styrene and 4 parts by mass of 1,3-butadiene at 65 ° C. for 45 minutes.
Next, polymerization was carried out by continuously supplying a cyclohexane solution containing 36 parts by mass of styrene at 65 ° C. for 45 minutes.
Thereafter, after holding for 10 minutes, methanol was added to the autoclave at a 1.0-fold molar ratio with respect to n-butyllithium to terminate the polymerization, and 2- [1- (2-hydroxy-3,5-di-oxide as a stabilizer. -T-pentylphenyl) ethyl] -4,6-di-t-pentylphenyl acrylate was added in an amount of 0.6 parts by mass based on 100 parts by mass of the copolymer.
Thereafter, the solvent was removed to obtain a block copolymer B-11.

<Olefin resin (III)>
Olefin resin C-1: Suntec-HD J240 (manufactured by Asahi Kasei Chemicals Corporation)
Olefin resin C-2: Suntec-LD M1820 (manufactured by Asahi Kasei Chemicals Corporation)
Olefin resin C-3: Sun Allomer PF621S (manufactured by Sun Allomer Co., Ltd.)

<Copolymer (IV)>
[Copolymer D-1]
PSJ polystyrene 475D (manufactured by PS Japan Co., Ltd.)
[Copolymer D-2]
PSJ polystyrene 685 (manufactured by PS Japan Ltd.)
[Copolymer D-3]
Tufprene 126 (Nippon Elastomer Co., Ltd., styrene content 40% by mass)
[Copolymer D-4]
D-4, which is an n-butyl acrylate-styrene copolymer, was added to a 10 L autoclave with a stirrer in a ratio of 15 parts by mass of styrene and 85 parts by mass of n-butyl acrylate, and simultaneously 0.3 kg of ethylbenzene. In order to adjust the molecular weight, a predetermined amount of 1,1 bis (t-butylperoxy) cyclohexane was charged, polymerized at 110 to 150 ° C. for 2 to 10 hours, and then unreacted styrene and n-butyl acrylate with a vent extruder. Ethylbenzene was recovered and produced.
The number average molecular weight of the copolymer D-4 was 216000.

Next, a method for measuring characteristics and an evaluation method applied in Examples and Comparative Examples will be described.
[(1) Block rate]
It can be measured by a method of oxidative decomposition with tertiary butyl hydroperoxide using osmium tetroxide as a catalyst (method described in IM KOLTHOFF, et al., J. Polym. Sci. 1, 429 (1946)). Was obtained from the following formula using the vinyl aromatic hydrocarbon polymer block component (excluding the vinyl aromatic hydrocarbon polymer component having an average degree of polymerization of about 30 or less).
In addition, by the above oxidative decomposition method, “the weight of the vinyl aromatic hydrocarbon polymer block polymer chain in the block copolymer” is determined, and “the total weight of the vinyl aromatic hydrocarbon in the block copolymer” is: It can be determined from the charge ratio at the time of polymerization or by analysis such as NMR.
Block ratio (mass%) = (weight of vinyl aromatic hydrocarbon polymer block polymer chain in block copolymer / total weight of vinyl aromatic hydrocarbon in block copolymer) × 100]

[(2) Dynamic viscoelasticity (tan δ peak temperature)]
Using a test piece having a thickness of about 1 mm obtained by compression-molding the pellets with a heating press, the temperature − The range of 100 ° C. to 150 ° C. was measured, and the peak temperature of tan δ was determined.

[(3) Number average molecular weight]
Using a GPC device (HLC8220GPC; manufactured by Tosoh Corporation), tetrahydrofuran was used as a solvent, and measurement was performed at a column temperature of 40 ° C.
The number average molecular weight was determined from a calibration curve prepared using a commercially available standard polystyrene having a known weight average molecular weight and number average molecular weight.
The block styrene number average molecular weight was measured using the vinyl aromatic hydrocarbon polymer block component obtained in (1) as a sample.

[(4) Tensile modulus (standard stiffness)]
As a test piece, what was cut out from the stretched film into a strip shape having a width of 10 mm in the MD and TD directions and a gap between the marked lines of 100 mm was used.
The measurement temperature was 23 ° C., the tensile rate was 10 mm / min, and the tensile modulus was obtained by a conventional method.
In addition, the average value of MD and TD direction was made into the value of the tensile elasticity modulus.

[(5) Shrinkage stress]
As a test piece, what was cut out into a strip shape from the stretched film to a length of 10 mm in the MD and TD directions and a measurement length of 60 mm was used.
One end of the test piece was fixed, a load detector was attached to the other end, immersed in an 80 ° C. hot water bath, and the load change for 30 seconds was measured.
Among these, the maximum heat shrinkage stress was calculated according to the following equation when the maximum load was f [dyne].
Here, d [μm] is the initial thickness of the test piece, and the maximum shrinkage stress is the maximum value among the heat shrinkage stresses measured in each direction in the film plane.
Thermal contraction stress (Pa) = 10 ³ × f / d
A smaller value is preferable for the shrinkage stress.

[(6) -5 ° C elongation]
As a test piece, what was cut out into a strip shape from the stretched film to a length of 15 mm in the MD direction and 40 mm between the marked lines was used.
The measurement temperature was −5 ° C. and the tensile speed was 100 mm / min.
Further, after 2 days from printing, the −5 ° C. elongation was measured in the same manner, and the retention (%) in comparison with the measured value immediately after film formation was calculated.
As for −5 ° C. elongation, a larger value is preferred, and a higher retention is preferred.

[(7) 80 ° C. shrinkage]
The stretched film (TD direction) was immersed in warm water at 80 ° C. for 10 seconds, and calculated according to the following formula.
80 ° C. thermal shrinkage (%) = (L−L1) / L × 100
Here, L indicates the length before contraction, and L1 indicates the length after contraction.
In general, it is preferable that the 80 ° C. shrinkage rate is large (shrinks well).

[(8) Natural shrinkage rate]
The stretched film (TD direction) was left at 35 ° C. for 5 days, and calculated according to the following formula.
Natural shrinkage (%) = (L2−L3) / L2 × 100
Here, L2 indicates the length before being left, and L3 indicates the length after being left.
The smaller the natural shrinkage rate, the better the natural shrinkage.

[Examples 1-9], [Comparative Examples 1-18]
Tables 4 to 6 below show blending formulations of the heat-shrinkable films of Examples 1 to 9 and Comparative Examples 1 to 18.
According to this compounding prescription, it was molded into a sheet having a thickness of 0.25 mm at 200 ° C. using a 40 mm extruder. Thereafter, the stretching temperature was set to 85 ° C., and a tenter was used to uniaxially stretch the stretching ratio along the horizontal axis to 5 times to obtain a heat-shrinkable film having a thickness of about 50 μm.
The film performance of this heat-shrinkable film is shown in Tables 4 to 6 below.

The heat-shrinkable films of Examples 1 to 9 have a natural shrinkage of 2.7% or less, an 80 ° C. shrinkage representing low-temperature shrinkage of 36% or more, and a tensile elastic modulus representing rigidity of 1340 MPa. It has a practically sufficient balance of physical properties, the −5 ° C. elongation is 200% or more immediately after film formation, the −5 ° C. elongation retention after 2 days of printing is 80% or more, and the shrinkage stress is It was 3.3 Mpa or less, and the retention rate of low-temperature elongation was high, the natural shrinkage rate was low, and the low shrinkage stress was also excellent.
In Comparative Examples 1 to 8, since the blending amount of the component (I) is out of the present invention, the natural shrinkage (good value is 2.7% or less), 80 ° C. shrinkage (good value is 36% or more) ), Tensile elastic modulus (good value is 1340 MPa or more), elongation at −5 ° C. (good value is 200% or more), retention rate of −5 ° C. elongation after 2 days after printing (good value is 80% or more) ) And any of the shrinkage stress (good value is 3.3 MPa or less), practically sufficient evaluation could not be obtained.
Since Comparative Examples 9 to 11 are not included in the composition of the present invention, Comparative Examples 9 and 11 cannot be stretched. In Comparative Example 10, a sufficient evaluation was not practically obtained at −5 ° C. .
In Comparative Examples 12 to 18, since the type of the block copolymer (II) is out of the present invention,
A practically sufficient evaluation could not be obtained in either the tensile modulus or the retention rate of −5 ° C. elongation.

  The heat-shrinkable film comprising the block copolymer hydrogenated composition of the present invention is excellent in the balance of physical properties such as natural shrinkage, low-temperature shrinkage and rigidity, and in particular, maintains low-temperature elongation and low shrinkage stress after film printing. Since it is excellent, it has industrial applicability as a material for thinned heat-shrinkable film materials, such as beverage container packaging, cap seals, and various labels.

Claims (11)

Block copolymer hydrogenated product (I). 5 to 40 wt%,
Block copolymer (II) 39 to 90% by mass,
Olefin resin (III) 5 to 25 % by mass,
Comprising a composition containing
The block copolymer hydrogenated product (I) is a hydrogenated product of a block copolymer composed of a vinyl aromatic hydrocarbon and a conjugated diene, and the vinyl aromatic hydrocarbon content is 55 to 80 % by mass. The block ratio of the vinyl aromatic hydrocarbon polymer contained in the polymer hydrogenated product (I) is 50 to 95% by mass, and the total vinyl aromatic hydrocarbon in the block copolymer hydrogenated product (I) The number average molecular weight of the polymer block is from 50,000 to 60,000, and at least one peak temperature of the function tan δ of dynamic viscoelasticity measurement is present at −40 ° C. or lower, and the vinyl aromatic hydrocarbon and the conjugated diene The hydrogenation rate of the double bond of the conjugated diene unit in the block copolymer consisting of is 10% or more and less than 50%,
The block copolymer (II) is a block copolymer comprising a vinyl aromatic hydrocarbon and a conjugated diene, a vinyl aromatic hydrocarbon content of less than 95 wt% than 85 wt%, said block copolymer and vinyl aromatic hydrocarbon polymer block ratio of contained in the polymer (II) is a 20 to 95 wt%, the number of total vinyl aromatic hydrocarbon polymer block in the block copolymer (II) The average molecular weight is 50,000 to 80,000, and at least one peak temperature of the function tan δ of dynamic viscoelasticity measurement is present at 60 to 110 ° C .;
The heat-shrinkable film in which the content of hydrogenated conjugated diene units in the composition is 0.5 to 10% by mass. The content of vinyl aromatic hydrocarbon in the block copolymer hydrogenated product (I) is 58 to 8.
0% by mass,
The block ratio of the vinyl aromatic hydrocarbon polymer contained in the block copolymer hydrogenated product (I) is 55 to 90% by mass,
The heat-shrinkable film according to claim 1, wherein the number average molecular weight of the all-vinyl aromatic hydrocarbon polymer block in the block copolymer hydrogenated product (I) is from 50,000 to 50,000. The block copolymer (II) has a vinyl aromatic hydrocarbon content of 87 to 93% by mass,
The block ratio of the vinyl aromatic hydrocarbon polymer contained in the block copolymer (II) is 30 to 85% by mass,
The number average molecular weight of the all-vinyl aromatic hydrocarbon polymer block in the block copolymer (II) is from 50,000 to 60,000, and the peak temperature of the dynamic viscoelasticity measurement function tan δ is from 70 to 105 ° C. The heat-shrinkable film according to claim 1 or 2, wherein at least one is present. The heat-shrinkable film according to any one of claims 1 to 3, wherein a content of the hydrogenated conjugated diene unit in the composition is 0.8 to 9% by mass. The heat shrink film according to any one of claims 1 to 4, wherein the composition further contains the following polymer (IV).
Here, the polymer (IV) is at least one polymer selected from the group consisting of the following (i) to (iv).
(I): a block copolymer comprising a vinyl aromatic hydrocarbon and a conjugated diene different from the components (I) and (II) or a hydrogenated product thereof.
(Ii) A copolymer comprising a vinyl aromatic hydrocarbon and an aliphatic unsaturated carboxylic acid derivative.
(Iii) Vinyl aromatic hydrocarbon polymer.
(Iv) A rubber-modified styrenic polymer. The heat-shrinkable film according to claim 5, comprising a composition containing a total of 60 to 99.9% by mass of (I) to (III) and 0.1 to 40 % by mass of (IV). A lubricant containing at least one selected from the group consisting of fatty acid amides, paraffins, hydrocarbon resins, and fatty acids,
The heat-shrinkable film according to any one of claims 1 to 4, further comprising 0.01 to 5 parts by mass with respect to a total of 100 parts by mass of (I), (II) and (III). A lubricant containing at least one selected from the group consisting of fatty acid amides, paraffins, hydrocarbon resins, and fatty acids,
0.0% of the total of 100 parts by mass of (I), (II), (III) and (IV).
The heat-shrinkable film according to claim 5 or 6, which contains 1 to 5 parts by mass. At least one selected from the group consisting of benzophenone-based UV absorbers, benzotriazole-based UV absorbers, hindered amine light stabilizers,
The heat-shrinkable film according to any one of claims 1 to 4 and 7, which is contained in an amount of 0.01 to 3 parts by mass with respect to a total of 100 parts by mass of the components (I), (II) and (III). At least one selected from the group consisting of benzophenone-based UV absorbers, benzotriazole-based UV absorbers, hindered amine light stabilizers,
0 parts per 100 parts by mass in total of the components (I), (II), (III) and (IV)
. The heat-shrinkable film according to any one of claims 5, 6, and 8, containing from 01 to 3 parts by mass.   A multilayer film comprising the heat-shrinkable film according to any one of claims 1 to 10.