JP2010234547A - Heat-shrinkable multilayer film - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a heat-shrinkable multilayer film excellent in the balance of physical properties such as naturale shrinkability, low-temperature shrinkability, and rigidity, and especially excellent in holding of low-temperature elongation after printing, low shrinking stress, and printability. <P>SOLUTION: A heat-shrinkable film of a multilayer structure is provided, wherein an intermediate layer is formed from a specific hydrogenated block copolymer composition consisting of a hydrogenated block copolymer (I), a block copolymer or its hydrogenated object (II), and an olefin resin (III), and a surface layer is formed of a block copolymer, or a mixed polymer containing the block copolymer and styrene polymer. <P>COPYRIGHT: (C)2011,JPO&INPIT

Description

  The present invention relates to a multilayer 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 widely used for food packaging, cap seals, labels, and the like.
The properties of such heat-shrinkable films are required to be excellent in natural shrinkage, low-temperature shrinkage, transparency, mechanical strength, suitability for packaging machinery, etc. Various studies have been made to obtain a good balance of physical properties.

Patent Document 1 discloses a composition in which a specific partially hydrogenated block copolymer is added to a styrene resin and an olefin resin.
Patent Document 2 discloses a hydrogenated copolymer having a specific structure and a heat-shrinkable film using the same.
Patent Document 3 discloses a block copolymer water having a specific storage elastic modulus (E ′) and loss elastic modulus (E ″), which includes a hydrogenated block copolymer having a specific structure and a polyolefin polymer. An additive composition is disclosed.
Patent Document 4 discloses a composition of a hydrogenated block copolymer having a specific structure and a vinyl aromatic hydrocarbon polymer.
Patent Document 5 discloses a block copolymer characterized by the block ratio in the block copolymer, the arrangement of the polymer block, and the conjugated diene content ratio of the randomly polymerized portion of the vinyl aromatic hydrocarbon and the conjugated diene. And a heat-shrinkable film using the same.
Patent Document 6 discloses a block copolymer comprising a vinyl aromatic hydrocarbon having a specific structure having vinyl aromatic hydrocarbon polymer blocks of different sizes at both ends and a conjugated diene, and a vinyl aromatic hydrocarbon resin. A composition containing is disclosed.
Patent Document 7 discloses a block copolymer composed of a vinyl aromatic hydrocarbon having a specific structure and a conjugated diene, in which the molecular weight of the vinyl aromatic hydrocarbon polymer block is in a specific range.
Patent Document 8 discloses a block copolymer having a specific structure composed of a vinyl aromatic hydrocarbon and a conjugated diene, and the block copolymer composition.
Patent Document 9 discloses a block copolymer composition comprising three kinds of vinyl aromatic hydrocarbons having a specific structure and a conjugated diene.
In Patent Document 10, as a heat-shrinkable film excellent in high transparency and gloss, excellent low-temperature shrinkage, 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 11 discloses a propylene resin and a petroleum resin as a heat-shrinkable film having excellent printability and dimensional stability and having a specific gravity of less than 0.960 between a front surface layer and a back surface layer made of a styrene resin. And an intermediate layer made of an adhesive resin is disclosed.

JP 2001-240713 A JP 2006-117879 A JP 2007-39662 A International Publication No. 06/109743 Pamphlet JP 7-97419 A JP 7-216187 A International Publication No. 03/91303 Pamphlet JP 2004-26917 A International Publication No. 06/75665 Pamphlet JP 2001-58377 A JP 2001-301102 A

  However, the heat-shrinkable film made of a vinyl aromatic hydrocarbon and a conjugated diene, or a composition thereof, disclosed in the above prior art, has a natural shrinkage, a low-temperature shrinkage, a rigidity, etc. The balance of physical properties, particularly the retention of low-temperature elongation after printing, the low shrinkage stress, and the printability cannot be said to be sufficient, and these documents do not provide any suggestions on how to improve them.

  Therefore, in the present invention, in view of the above-mentioned problems of the prior art, it has an excellent balance of physical properties such as natural shrinkage, low-temperature shrinkage and rigidity, and transparency, retention of low-temperature elongation after printing, low shrinkage stress, and printability. Further, a heat shrinkable film having excellent characteristics is provided.

As a result of intensive studies to achieve the above object, the present inventors have used a block copolymer hydrogenated composition having a specific structure as the first layer and a specific vinyl aromatic as the second layer. By producing a heat-shrinkable multilayer film using a specific mixed polymer resin having a hydrocarbon content, it has an excellent balance of physical properties of natural shrinkage, low-temperature shrinkage and rigidity, and maintains low-temperature elongation after printing. It has been found that a multilayer heat-shrinkable film capable of realizing low shrinkage stress and excellent printability can be obtained, and the present invention has been completed.
That is, the present invention is as follows.

[1] A multilayer heat-shrinkable film comprising a first layer and a second layer, wherein the first layer and the second layer are laminated,
The first layer is formed of the following block copolymer hydrogenated composition (α),
The second layer is a block copolymer containing a vinyl aromatic hydrocarbon and a conjugated diene hydrocarbon, or a mixed polymer obtained by blending a styrene polymer with the block copolymer, or these Are formed of a mixed polymer comprising two or more different types of block copolymers.
The block copolymer hydrogenated composition (α) is:
Block copolymer hydrogenated product (I): 5 to 90% by mass
Block copolymer or hydrogenated product (II) thereof: 5 to 90% by mass
Olefin resin (III): 5 to 90% by mass
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 85% by mass. The block ratio of the vinyl aromatic hydrocarbon polymer contained in the block copolymer hydrogenated product (I) is 50 to 95% by mass, and the total vinyl aroma in the block copolymer hydrogenated product (I) The aromatic hydrocarbon polymer block has a number average molecular weight of 50,000 to 60,000, and at least one peak temperature of the function tan δ of dynamic viscoelasticity measurement is −40 ° C. or lower, and the vinyl aromatic hydrocarbon And the hydrogenation rate of the double bond of the conjugated diene unit in the block copolymer comprising conjugated diene is 10% or more and less than 50%,
The block copolymer or hydrogenated product (II) thereof is a block copolymer consisting of a vinyl aromatic hydrocarbon and a conjugated diene or a hydrogenated product thereof, and the vinyl aromatic hydrocarbon content is 85% by mass. The block ratio of the vinyl aromatic hydrocarbon polymer contained in the block copolymer or the hydrogenated product (II) thereof is 20 to 95% by mass, The number average molecular weight of the all-vinyl aromatic hydrocarbon polymer block in the coalescence or its hydrogenated product (II) is from 50,000 to 80,000, and the peak temperature of the function tan δ of dynamic viscoelasticity measurement is from 60 to 110 At least one at
Provided is a multilayer heat-shrinkable film in which the content of hydrogenated conjugated diene units in the block copolymer hydrogenated composition (α) is 0.5 to 10% by mass.

[2] The vinyl aromatic hydrocarbon content in the block copolymer hydrogenated product (I) is 58 to 80% 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 multilayer heat-shrinkable film according to [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. provide.

[3] The block copolymer or the hydrogenated product (II) thereof 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 or hydrogenated product (II) thereof is 30 to 85% by mass, and the block copolymer or hydrogenated product (II) thereof. The number average molecular weight of the all-vinyl aromatic hydrocarbon polymer block is 50,000 to 60,000, and at least one peak temperature of the function tan δ of dynamic viscoelasticity measurement is 70 to 105 ° C. [1 Or a multilayer heat-shrinkable film according to [2].

[4] Any of [1] to [3], wherein the hydrogenated conjugated diene unit content in the hydrogenated block copolymer composition (α) is 0.8 to 9% by mass. A multilayer heat-shrinkable film according to claim 1 is provided.

[5] The multilayer heat-shrinkable film according to any one of [1] to [4], wherein the block copolymer hydrogenated composition (α) further contains the following polymer (IV): provide.
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] Block copolymer hydrogenated composition (α) containing a total of 50 to 99.9% by mass of the components (I) to (III) and 0.1 to 50% by mass of the component (IV) The multilayer heat-shrinkable film according to the above [5], comprising the first layer formed by the above method.

[7] The multilayer heat-shrinkable film according to any one of [1] to [6], wherein the content of the vinyl aromatic hydrocarbon in the second layer is 75 to 85% by mass.

[8] The second layer contains 13 to 20% by mass of a component having a loss elastic modulus (E ″) measured at a vibration frequency of 35 Hz of −25 ° C. or less. ] The multilayer heat-shrinkable film as described in any one of the above.

[9] The multilayer heat shrinkability according to any one of [1] to [8], further including a third layer on the side of the first layer opposite to the surface on which the second layer is formed. Provide film.

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

  Hereinafter, although the form for implementing this invention (henceforth this embodiment) is demonstrated, this invention is not limited to the form shown below.

[Multilayer heat shrinkable film]
The heat-shrinkable film of the present embodiment is a multilayer heat-shrinkable film that includes a first layer and a second layer.
The first layer is formed of a block copolymer hydrogenated composition (α) described later.
The second layer is a block copolymer containing a vinyl aromatic hydrocarbon and a conjugated diene hydrocarbon, a mixed polymer obtained by blending a styrene polymer with the block copolymer, or a It is formed of a mixed polymer obtained by blending two or more different types of block copolymers.

[First layer constituting multilayer heat-shrinkable film]
The block copolymer hydrogenated composition (α) constituting the first layer is composed of a block copolymer hydrogenated product (I): 5 to 90% by mass, a block copolymer or a hydrogenated product thereof (II ): 5 to 90% by mass, olefin resin (III): 5 to 90% by mass.

  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 has a vinyl aromatic hydrocarbon content of 55 to 85% by mass. . The block ratio of the vinyl aromatic hydrocarbon polymer contained in the block copolymer hydrogenated product (I) is 50 to 95% by mass, and the number average molecular weight of the all vinyl aromatic hydrocarbon polymer block is 0.00. Conjugation in the block copolymer of 50,000 to 60,000, wherein at least one peak temperature of the function tan δ of dynamic viscoelasticity measurement is −40 ° C. or lower, and is composed of the vinyl aromatic hydrocarbon and the conjugated diene. The hydrogenation rate of double bonds of diene units is 10% or more and less than 50%.

  The block copolymer or hydrogenated product (II) thereof is a block copolymer consisting of a vinyl aromatic hydrocarbon and a conjugated diene or a hydrogenated product thereof, and the vinyl aromatic hydrocarbon content is 85% by mass. Exceeding 95% by mass. The block ratio of the vinyl aromatic hydrocarbon polymer contained in the block copolymer or hydrogenated product (II) thereof is 20 to 95% by mass, and the number average molecular weight of the total vinyl aromatic hydrocarbon polymer block Is from 50,000 to 80,000, and there is at least one peak temperature of the function tan δ of dynamic viscoelasticity measurement at 60 to 110 ° C.

  Content of the hydrogenated conjugated diene unit in the said block copolymer hydrogenated composition ((alpha)) is 0.5-10 mass%.

The component which comprises the said block copolymer hydrogenated composition ((alpha)) is demonstrated.
(Block copolymer water additive (I): component (I))
The block copolymer hydrogenated product (I) is a hydrogenated product of a block copolymer composed of 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 weight, 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 that is excellent in rigidity and retention of 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 vinyl aromatic hydrocarbon content 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 vinyl aromatic hydrocarbon polymer block polymer chain in the block copolymer” is obtained, and “the total weight of 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 all-vinyl aromatic hydrocarbon polymer block is in the range of 50,000 to 60,000, the finally obtained multilayer 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 preparing a calibration curve between the peak count number and the number average molecular weight of monodisperse polystyrene by GPC using monodisperse polystyrene for gel permeation chromatography (GPC), and using this standard method ( For example, it is calculated according to “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 dynamic viscoelasticity measurement function tan δ can be measured by, for example, a viscoelasticity measurement / analysis apparatus DVE · V4 manufactured by Rheology Co., Ltd., Leo Vibron DDV • 3 type manufactured by Toyo Baldwin. 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 of the tan δ value with respect to the temperature 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, the microstructure of the conjugated diene, and the like.
Specifically, at least one of the copolymer parts composed of a vinyl aromatic hydrocarbon and a conjugated diene has a vinyl aromatic hydrocarbon content of 50% by mass or less, a vinyl aromatic hydrocarbon and a 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 multilayer 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 or more ligands having a (substituted) cyclopentadienyl skeleton, indenyl skeleton, or fluorenyl skeleton such as biscyclopentadienyl titanium dichloride and monopentamethylcyclopentadienyl titanium trichloride. Compounds having the same.
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 in 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 either a batch process or 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 part of the hydrogenated block copolymer (block copolymer water additive: component (I)) can be arbitrarily determined by using polar compounds or the like. Can be changed.
Generally, the vinyl bond amount (block copolymer water additive: vinyl bond amount of component (I)) can be set in the range of 5 to 90%, preferably 10 to 80%, more preferably 15 to 75%.
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 thereof (II): Component (II))
The block copolymer constituting the block copolymer hydrogenated composition (α) or its hydrogenated product (II) is a block copolymer comprising a vinyl aromatic hydrocarbon and a conjugated diene or a hydrogenated product thereof. is there.
The vinyl aromatic hydrocarbon content is more than 85% by mass and less than 95% by mass, preferably 87 to 93% by mass, and 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 multilayer 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 all-vinyl aromatic hydrocarbon polymer block of the component (II) is in the range of 50,000 to 80,000, a multilayer heat shrinkable film excellent in low shrinkage stress and low temperature shrinkability is obtained. It is done. 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 multilayer 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 multilayer heat-shrinkable film excellent in low-temperature shrinkage is obtained, exceeding 50% and not more than 100% When the thickness is in the range, a multilayer 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. At least one segment composed of a conjugated diene homopolymer and / or a copolymer composed of a vinyl aromatic hydrocarbon and a 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 ( The linear block copolymer represented by 3) or a hydrogenated product thereof, a radial block copolymer or the hydrogenated product thereof, or any mixture of these polymer structures can be used.
(AB) n, A- (BA) n, B- (AB) n + 1 (1)
[(AB) k] m + 1-X, [(AB) k-A] 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) constituting the block copolymer hydrogenated composition (α) is at least one polymer selected from polypropylene resins, polyethylene polymers and the like, 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, ethylene ionomer resins, ethylene-α olefin copolymers, etc.), modified polymers having carboxylic acid groups added thereto, polybutene-1 copolymers, etc. The main component is at least one selected component.
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 block copolymer hydrogenated composition (α), the weight ratio of the component (I) to the component (II) and the component (III) ) / Component (II) / component (III), it is 5 to 90/5 to 90/5 to 90, preferably 10 to 80/10 to 80/10 to 80, and 15 to 70 /. It is more preferable that it is 15-70 / 15-70.
The content of the hydrogenated conjugated diene unit in the composition (α) is 0.5 to 10% by mass, preferably 0.8 to 9% by mass, more preferably 1 to 7% by mass. It is.
As described above, the weight ratio of component (I), component (II), and component (III) is in the range of 5 to 90/5 to 90/5 to 90, where 100 is the total composition (α). If the content of the hydrogenated conjugated diene unit is in the range of 0.5 to 10% by mass, the final multilayer heat-shrinkable film can maintain low temperature elongation and low temperature elongation after printing. It will be excellent.

(Polymer (IV): Component (IV))
The block copolymer hydrogenated composition (α) may further contain the following polymer (IV).
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): a polymer structure of a block copolymer comprising a vinyl aromatic hydrocarbon and a conjugated diene different from those of component (I) and component (II) (hereinafter sometimes referred to as component (i)). (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. The above-mentioned aliphatic unsaturated carboxylic acid derivatives are generally esters, mainly esters such as ethyl acrylate, propyl acrylate, butyl acrylate, hexyl acrylate and octyl acrylate. 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, and 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.
By using the aliphatic unsaturated carboxylic acid ester-styrene copolymer mainly composed of n-butyl acrylate and styrene, the intended low-temperature shrinkability of the multilayer heat-shrinkable film is finally improved.

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.
Component (iii): The vinyl aromatic hydrocarbon polymer can be used as a rigidity improving agent for the multilayer heat-shrinkable film of this embodiment.

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.

From the viewpoint of molding, the MFR of the components (i) to (iv) described above (temperature 200 ° C., load 5 Kg under G condition) is preferably 0.1 to 100 g / 10 min, and 0.5 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 components (I) to (III) is 60 to 99% by mass and the component (IV) is 1 to 40% by mass.
Multi-layer heat-shrinkability excellent in 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. A film is obtained.

[Second layer constituting multilayer heat-shrinkable film]
The second layer constituting the multilayer heat-shrinkable film of this embodiment is a block copolymer containing a vinyl aromatic hydrocarbon and a conjugated diene hydrocarbon, or a styrene polymer in the block copolymer. It is assumed that it is formed of a mixed polymer formed by blending or a mixed polymer formed by blending two or more types of block copolymers different from these.
The content of the vinyl aromatic hydrocarbon in the second layer is preferably 70 to 90% by mass, and more preferably 75 to 85% by mass.
By setting the content of the vinyl aromatic hydrocarbon in the second layer in the range of 70 to 90% by mass, the multilayer heat-shrinkable film of this embodiment has excellent rigidity and printability.

The second layer contains 10 to 25% by mass, preferably 13 to 20% by mass of a component having a loss elastic modulus (E ″) measured at a vibration frequency of 35 Hz of −25 ° C. or lower. .
A multilayer having excellent retention of elongation after printing by setting the content of the component having a loss elastic modulus (E ″) peak temperature of −25 ° C. or less measured at a vibration frequency of 35 Hz of the second layer within the above range. It can be set as a heat-shrinkable film.
The content of the component having a loss elastic modulus (E ″) peak measured at a vibration frequency of 35 Hz of the second layer of −25 ° C. or lower is determined by the conjugated diene polymer block or vinyl aromatic present in the block copolymer. It can be controlled by the composition and mass of the copolymer block portion composed of hydrocarbon and conjugated diene.
For example, the content of the conjugated diene polymer block is a block copolymer containing a vinyl aromatic hydrocarbon and a conjugated diene hydrocarbon constituting the second layer, or a styrene-based block copolymer. Loss elastic modulus measured at a vibration frequency of 35 Hz if the blended polymer is a mixed polymer obtained by blending a polymer or 20% by mass of a blended polymer obtained by blending two or more different types of block copolymers. The peak temperature of the loss elastic modulus (E ″) of the component having (E ″) of −25 ° C. or lower is −85 ° C., and the component amount (loss elastic modulus (E ″) measured at a vibration frequency of 35 Hz is −25). The amount of the component that is not higher than ° C.) is 20% by mass.

In the case where the second layer is a copolymer block composed of a vinyl aromatic hydrocarbon and a conjugated diene, sampling is performed at the end of polymerization of the copolymer block portion during the polymerization reaction, and the copolymer block portion The peak temperature of the loss elastic modulus (E ″) can be determined, and the component amount can be determined from the weight of the copolymer block portion.
The peak temperature of the loss modulus (E ") of the copolymer block composed of vinyl aromatic hydrocarbon and conjugated diene approaches -85 ° C when the conjugated diene content increases, and the vinyl aromatic hydrocarbon content increases. When it increases, the temperature exceeds -25 ° C.
For this reason, it can control easily and with high precision by adjusting the mass ratio of conjugated diene and vinyl aromatic hydrocarbon.

The second layer constituting the multilayer heat-shrinkable film of this embodiment is a block copolymer composed of a vinyl aromatic hydrocarbon and a conjugated diene hydrocarbon, or a styrene polymer blended with the block copolymer. Or a mixed polymer obtained by blending two or more different types of block copolymers. The structure of the block copolymer and the structure of each block portion are not particularly limited.
The block copolymer constituting the second layer comprises (i) the component (I), the component (II), and the polymer (IV), a vinyl aroma different from the component (I) and the component (II). It may be a block copolymer composed of a group hydrocarbon and a conjugated diene.
The structure of each block portion of the block copolymer is not particularly limited, and examples thereof include a completely symmetric block, an asymmetric block, a tetra block, a tapered block, and a random block. Among them, a random block is preferable.

[Other ingredients: Lubricant]
The first layer and / or the second layer described above 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 can be used.
The added amount is 0.01 to 5 parts by mass, preferably 0.05 to 4 parts by mass with respect to 100 parts by mass of all materials constituting the first layer and / or 100 parts by mass of all materials constituting the second layer. By adding 0.1 part by mass, more preferably 0.1-3 parts by mass, the heat-shrinkable film has good blocking resistance.

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]
The first layer and / or the second layer described above may contain an ultraviolet absorber and / or a light stabilizer.
As the ultraviolet absorber and light stabilizer, at least one ultraviolet absorber and / or light stabilizer selected from benzophenone ultraviolet absorbers, benzotriazole ultraviolet absorbers, and hindered amine light stabilizers can be applied.
The addition amount is not particularly limited, and is 0.05 to 3 parts by mass with respect to 100 parts by mass of the heat-shrinkable film of the present embodiment (the total weight of the first layer, the second layer, and the like). By adding 0.05 to 2.5 parts by mass, more preferably 0.1 to 2 parts by mass, the effect of improving the light resistance of the multilayer heat-shrinkable film can be 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-pentame 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]
A predetermined stabilizer is preferably added to the first layer and / or the second layer.
It does not specifically limit as a stabilizer, For example, a phenol type stabilizer, an organic phosphate type, and / or an organic phosphite type stabilizer etc. are mentioned.
The addition amount of the stabilizer is not particularly limited, and preferably 0.05 to 3 when the material constituting the first layer is 100 parts by mass and / or the material constituting the second layer is 100 parts by mass. Part by mass is preferable, and 0.1 to 2 parts by mass is more preferable. Thereby, the gel suppression effect is acquired.

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.

It is preferable that the first layer and / or the second layer described above contain an organic phosphate-based and / or organic phosphite-based stabilizer.
Specifically, tris- (nonylphenyl) phosphite, 2,2-methylenebis (4,6-di-t-butylphenyl) octyl phosphite, 2-[[2,4,8,10-tetrakis (1 , 1-dimethylethyl) dibenzo [d, f] [1,3,2] dioxaphosphin-6-yl] oxy] -N, N-bis [2-[[2,4,8,10- Tetrakis (1,1-dimethylethyl) dibenzo [d, f] [1,3,2] dioxaphosphine-6-yl] oxy] -ethyl] -ethanamine, tris (2,4-di-t- Butylphenyl) phosphite and the like.
These may be used alone or in combination of two or more.

[Other ingredients: Additives]
Various additives can be added to the first layer and / or the second layer described above depending on 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 0.01 to 5% by mass, preferably 0.05 to 3% by mass, when the material constituting the first layer and / or the material constituting the second layer is 100% by mass. It is used in the range.

[Method for producing composition constituting first layer and second layer of multilayer heat-shrinkable film]
The manufacturing method of the composition which comprises a 1st layer and a 2nd layer is not specifically limited, It can manufacture by 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.

[Method for producing multilayer heat-shrinkable film]
The multilayer heat-shrinkable film of this embodiment can be a heat-shrinkable uniaxial or biaxially stretched film.
The stretching method is not particularly limited, and a conventionally known method can be applied.
For example, the material is extruded from a normal T die or an annular die into a flat shape or a tube shape at a temperature of 150 to 250 ° C., preferably 170 to 220 ° C., and the obtained unstretched product is substantially 1 It can be produced by a method of axial stretching or biaxial stretching, a method of producing a raw sheet before stretching as a first inflation step, and obtaining a heat-shrinkable film by a inflation method again in a fluid as a second inflation step. .

In the case of uniaxial stretching, the stretching direction or the like is not particularly limited. For example, in the case of a film or sheet, the film 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, and is tubular In the case of, it can be stretched in the tube extrusion direction or circumferential direction.
In the case of biaxial stretching, the stretching direction and the like are not particularly limited. For example, 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. In the case of a tube shape, the tube can be stretched simultaneously or separately in the tube extrusion direction and the tube circumferential direction, that is, in a direction perpendicular to the tube axis. When continuously producing a biaxially stretched film, it is preferable to stretch in the MD direction and the TD direction.

The stretching conditions are not particularly limited, and the conditions can be appropriately set according to desired physical properties.
The stretching temperature is preferably 60 to 130 ° C, more preferably 70 to 120 ° C, and further preferably 80 to 110 ° C.
By setting the stretching temperature to 60 ° C. or higher, the occurrence of breakage during stretching can be suppressed, and a desired multilayer heat-shrinkable film can be obtained. By setting the stretching temperature to 130 ° C. or lower, a multilayer heat-shrinkable film having excellent shrinkage characteristics can be obtained.
A draw ratio is not specifically limited, It can select within the said range so that it may respond | correspond with the shrinkage rate required by a use. The draw ratio is preferably 1.5 to 8 times, more preferably 2 to 6 times in the machine direction and / or the transverse direction. By setting the draw ratio to 1.5 times or more, a film having a large heat shrinkage ratio and preferable for heat shrink wrapping can be obtained. By setting the draw ratio to 8 times or less, stable productivity in the drawing process can be secured.
In the case of biaxial stretching, the stretching ratios in the longitudinal direction and the transverse direction may be the same or different.

The multilayer heat-shrinkable film subjected to uniaxial stretching or biaxial stretching is preferably subjected to heat treatment to prevent spontaneous shrinkage at room temperature, if necessary.
The temperature of heat processing is not specifically limited, From a shrinkable viewpoint, Preferably it is 60-160 degreeC, More preferably, it is 80-155 degreeC. The treatment time of the heat treatment is not particularly limited, and is preferably 3 to 60 seconds, more preferably 10 to 40 seconds from the viewpoint of shrinkability.

The multilayer heat-shrinkable film thus obtained can be used as a heat-shrinkable packaging material such as a shrink film or a heat-shrinkable label material.
To be used as a heat-shrinkable packaging material or a heat-shrinkable label material, the heat shrinkage rate at 80 ° C. in the stretching direction is preferably 10 to 80%, more preferably 10 to 75%. More preferably, it is 15 to 70%.
When the heat shrinkage is in the above range, a multilayer heat shrinkable film having an excellent balance between the heat shrinkage and the natural shrinkage is obtained.

  In addition, in the multilayer heat-shrinkable film of this embodiment, it can be said that the heat shrinkage rate at 80 ° C. is 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.

When the multilayer heat-shrinkable film of the present embodiment is in the range of the heat shrinkage rate, the natural shrinkage rate of the heat-shrinkable film itself is preferably 4.0% or less, and is 3.5% or less. Is more preferable, and it is further more preferable that it is 3.0% or less. By setting the natural shrinkage ratio in such a range, the dimensional change of the film can be reduced, which is preferable.
Here, the natural shrinkage rate of the multilayer heat-shrinkable film itself is a value calculated by an equation described later after leaving the multilayer 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 multilayer 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.
It is preferable to set the tensile elastic modulus in the stretching direction to 700 MPa or more because the occurrence of settling can be suppressed and normal packaging can be achieved in the shrink wrapping process. A tensile elastic modulus of 3000 MPa or less is preferable because the impact resistance of the film can be improved.

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

The multilayer heat-shrinkable film of this embodiment should just be the structure which comprises two layers, a 1st layer and a 2nd layer, and may comprise the other layer.
For example, the above-described first layer is an intermediate layer, the above-described second layer stacked on the first layer is a surface layer, and the first layer has a predetermined third on the side opposite to the second layer. A multilayer heat-shrinkable film having a three-layer structure provided with the above layer (back surface layer).
The third layer may be the same component as the second layer or a different component. That is, the same composition may be sufficient as the 2nd layer used as a surface layer, and the 3rd layer used as a back surface layer, and a different composition may be sufficient as it.
In particular, in a multilayer laminate having a three-layer structure in which the first layer is an intermediate layer and sandwiched between two second layers, if the front and back layers have good solvent resistance, elongation after printing It is possible to obtain characteristics such as excellent resistance.

The thickness of the multilayer heat-shrinkable film of the present embodiment is not particularly limited, is preferably 10 to 300 μm, preferably 20 to 200 μm, and more preferably 30 to 100 μm.
Although the thickness ratio of the first layer and the second layer constituting the multilayer heat-shrinkable film of the present embodiment is not particularly limited, (the thickness of the second layer and other layers) (Total) / (thickness of the first layer) is preferably 5/95 to 45/55, more preferably 10/90 to 35/65.

[Use]
The multilayer 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, a so-called heat-shrinkable label material (shrink) is used that is printed on a letter or design and then adhered to the surface of a packaged article such as a plastic molded product, metal product, glass container, porcelain, etc. Label, shrink film, etc.).
The multilayer heat-shrinkable film in the present embodiment may be given design properties by performing predetermined processing such as embossing.
The multilayer heat-shrinkable film of the present embodiment is excellent in rigidity and low-temperature elongation, so that it can be deformed when heated to a high temperature, in addition to the heat-shrinkable label material of plastic molded products, thermal expansion coefficient, water absorption, etc. Are very different materials (for example, polyolefin resin such as metal, porcelain, glass, paper, polyethylene, polypropylene, polybutene; polyester resin such as polymethacrylate resin, polycarbonate resin, polyethylene terephthalate, polybutylene terephthalate; polyamide) Can be suitably used as a heat-shrinkable label material for containers that can be used as a constituent material.
Examples of the material of the plastic container when using the multilayer heat-shrinkable film of the present embodiment as a label include polystyrene, rubber-modified impact-resistant polystyrene (HIPS), styrene-butyl acrylate copolymer, styrene-acrylonitrile copolymer. Polymer, styrene-maleic anhydride copolymer, acrylonitrile-butadiene-styrene copolymer (ABS), methacrylate-butadiene-styrene copolymer (MBS), polyvinyl chloride resin, polyvinyl chloride resin, phenol Examples thereof include resins, urea resins, melamine resins, epoxy resins, unsaturated polyester resins, and silicone resins.
The material of these plastic containers may be a mixture of two or more kinds of resins, or a laminate of these.

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

[Production example of components (I) to (IV) constituting the first layer]
<Example of production of hydrogenated block copolymer (I)>
Block copolymer hydrogenated products A-1 to A-13 used in Examples and Comparative Examples described later were prepared by the following method.
Hydrogenated block copolymer before the cyclohexane solvent, the n- butyl lithium as a catalyst, to produce tetramethylethylenediamine randomizing agent, the structure shown in the following Table 1, styrene content (mass%), the block rate 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 rate 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, a 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 with sufficient stirring. The hydrogenation catalyst which added the n-hexane solution containing and made it react at room temperature for about 3 days was used.
In Table 1 below, “Structure of hydrogenated block copolymer”, “Structure of block copolymer” in Table 2, and “Structure of block copolymer” in Table 4, A is a polystyrene part. , B represents a random copolymer part of styrene and butadiene, and C represents a polybutadiene part, but the numbers given to these parts are different (for example, A1 and A2), or the number is not marked. (For example, B1 and B) indicate that they are not limited to the same one but may have different weights and molecular weights. 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 carried out 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 carried out 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 and 0.3 times tetramethylethylenediamine with respect to n-butyllithium in a cyclohexane solution containing 38 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 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 in a molar ratio of 1.0 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, in a cyclohexane solution containing 37 parts by mass of styrene, 0.094 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 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 in a molar ratio of 1.0 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-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 in a molar ratio of 1.0 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 performed 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, a cyclohexane solution containing 5 parts by mass of styrene was continuously supplied at 65 ° C. for 10 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 in a molar ratio of 1.0 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% of tetramethylethylenediamine with respect to n-butyllithium were added. Double moles were 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 performed 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 in a molar ratio of 1.0 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 performed 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 rate 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, a 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 and 0.3 times mol of tetramethylethylenediamine with respect to n-butyllithium in a cyclohexane solution containing 25 parts by mass of styrene Polymerization was carried out by continuously adding 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 The polymerization was carried out by continuously feeding at 65 ° C. for 20 minutes.
Next, polymerization was performed 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 carried out 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 carried out 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 are 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 carried out 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, 0.038 parts by mass of n-butyllithium and 0.3 times of tetramethylethylenediamine with respect to n-butyllithium were added to a cyclohexane solution containing 4 parts by mass of styrene. 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 76 parts by mass of styrene and 15 parts by mass of 1,3-butadiene at 65 ° C. for 100 minutes.
Next, polymerization was performed 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, a cyclohexane solution containing 46 parts by mass of styrene was continuously supplied at 65 ° C. for 55 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-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 carried out 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.

[Example of production of block copolymer constituting second layer]
Block copolymers E-1 to E-5 used in Examples and Comparative Examples described later were prepared by the following method.
Block copolymers having the structure, styrene content (% by mass), and number average molecular weight shown in Table 4 below were produced.
The styrene content was adjusted by adding styrene and butadiene.
The number average molecular weight was adjusted by the catalyst amount.
In the preparation of the block copolymer, a monomer diluted with cyclohexane to a concentration of 20% by mass was used.

[Block copolymer E-1]
Using an autoclave equipped with a stirrer, in a nitrogen gas atmosphere, in a cyclohexane solution containing 4 parts by mass of styrene, 0.050 part by mass of n-butyllithium and tetramethylethylenediamine 0.3 times that of 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 80 parts by mass of styrene and 13 parts by mass of 1,3-butadiene at 65 ° C. for 110 minutes.
Next, polymerization was carried out by continuously supplying a cyclohexane solution containing 3 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 E-1.

[Block copolymer E-2]
Using an autoclave equipped with a stirrer, in a nitrogen gas atmosphere, 0.046 parts by mass of n-butyllithium and 0.04 parts by mass of tetramethylethylenediamine with respect to n-butyllithium were added to a cyclohexane solution containing 53.8 parts by mass of styrene. The polymerization was carried out by adding 3 moles and feeding continuously at 65 ° C. for 60 minutes.
Next, polymerization was performed by continuously supplying a cyclohexane solution containing 5 parts by mass of 1,3-butadiene at 65 ° C. for 10 minutes.
Next, polymerization was performed by continuously supplying a cyclohexane solution containing 34.2 parts by mass of styrene and 7 parts by mass of 1,3-butadiene 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 E-2.

[Block copolymer E-3]
Using an autoclave equipped with a stirrer, in a nitrogen gas atmosphere, in a cyclohexane solution containing 35 parts by mass of styrene, 0.065 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 carried out by continuously supplying a cyclohexane solution containing 33 parts by mass of 1,3-butadiene at 65 ° C. for 40 minutes.
Next, polymerization was performed by continuously supplying a cyclohexane solution containing 32 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 E-3.

[Block copolymer E-4]
Using an autoclave equipped with a stirrer, in a nitrogen gas atmosphere, in a cyclohexane solution containing 5 parts by mass of 1,3-butadiene, 0.063 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, polymerization was carried out by continuously supplying a cyclohexane solution containing 30 parts by mass of styrene at 65 ° C. for 35 minutes.
Next, polymerization was performed by continuously supplying a cyclohexane solution containing 1.8 parts by mass of styrene and 35 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 28.2 parts by mass of styrene 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 E-4.

[Block copolymer E-5]
Using an autoclave equipped with a stirrer, in a nitrogen gas atmosphere, in a cyclohexane solution containing 29.8 parts by mass of styrene, 0.070 parts by mass of n-butyllithium and 0.4% of tetramethylethylenediamine with respect to n-butyllithium were added. The polymerization was carried out by adding 3 times mol and continuously feeding at 65 ° C. for 40 minutes.
Next, polymerization was carried out by continuously supplying a cyclohexane solution containing 3 parts by mass of 1,3-butadiene at 65 ° C. for 10 minutes.
Next, polymerization was carried out by continuously supplying a cyclohexane solution containing 3.2 parts by mass of styrene and 34 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 30 parts by mass of styrene 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 E-5.

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).
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]
In addition, by the above oxidative decomposition method, “the weight of vinyl aromatic hydrocarbon polymer block polymer chain in the block copolymer” is obtained, and “the total weight of 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.

[(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 apparatus (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 speed 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 a stretched film to a length having a width 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
It was judged that the shrinkage stress is preferably smaller.

[(6) -5 ° C elongation]
As a test piece, what was cut out from the stretched film into a strip shape with a width of 15 mm in the MD direction and a gap between the marked lines of 40 mm 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 was determined that the 80 ° C. shrinkage ratio is preferably larger (shrinks well).

[(8) Natural shrinkage]
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.

[(10) Printability]
As a printing apparatus, a gravure mini proofreader CM type (manufactured by Nissho Gravure Co., Ltd.) was used.
Using a gradation plate having a line number of 175 L / inch and an ink density of 0 to 100 as a plate, film printing was performed with black ink, and gradation evaluation was visually evaluated according to the following criteria.
<Evaluation criteria>
○: There is no shading boundary in the gradation.
Δ: A slight light / dark boundary is recognized in the gradation.
X: A light and dark border is clearly recognized in the gradation.
○ to Δ: The gradation boundary between gradations is intermediate between ○ and Δ.

[Examples 1-9], [Comparative Examples 1-17]
A three-layer sheet having a surface layer, an intermediate layer, and a back layer was prepared using materials having the formulation shown in Tables 5 to 7 below.
It was extruded from a T-die at 200 ° C., stretched 1.2 times in the longitudinal direction, and formed into a sheet having a thickness of 0.25 mm.
Thereafter, the stretching temperature was set to 85 ° C., and a tenter was used to uniaxially stretch the stretching ratio 5 times on the horizontal axis to obtain a heat-shrinkable film having a thickness of about 50 μm.
In each example and each comparative example, the ratio (%) of the thickness of the intermediate layer to the surface layer / back surface layer was 10 (surface layer) / 80 (intermediate layer) / 10 (back surface layer).

  The physical properties of the heat-shrinkable films of Examples 1 to 9 are shown in Table 8 below, and the physical properties of the heat-shrinkable films of Comparative Examples 1 to 17 are shown in Table 9 and Table 10 below.

The multilayer heat-shrinkable films of Examples 1 to 9 had practically sufficiently excellent tensile elastic modulus, retention after printing at −5 ° C., 80 ° C. shrinkage, natural shrinkage, shrinkage stress, and printability. became.
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 3.7% or less), 80 ° C. shrinkage (good value is 33% or more) ), Tensile elastic modulus (good value is 1340 MPa or more), elongation at −5 ° C. (good value is 190% or more), retention rate at −5 ° C. 2 days after printing (good value is 81% or more) ) And any shrinkage stress (good value is 3.7 MPa or less), a practically sufficient evaluation could not be obtained.
Comparative Example 9 is low in the blending ratio of component (II) and deviates from the present invention. Therefore, Comparative Examples 12 and 14 are high in tan δ peak temperature of component (II) and deviated from the present invention. could not.
In Comparative Example 10, since the composition was out of the present invention, practically sufficient evaluation could not be obtained for the elongation at −5 ° C.
In Comparative Examples 11 to 17, since the type of the block copolymer (II) is out of the present invention, a practically sufficient evaluation is obtained in terms of tensile elastic modulus, -5 ° C. elongation retention rate and shrinkage stress. There wasn't.
From the above, it can be seen that the heat-shrinkable film of this embodiment is excellent in the balance of physical properties such as natural shrinkage, low-temperature shrinkage and rigidity, and excellent in maintaining low-temperature elongation after printing, low shrinkage stress and printability. It was done.

  The multilayer heat-shrinkable film of the present invention has a good balance of physical properties such as natural shrinkage, low-temperature shrinkage and rigidity, and also has excellent low temperature elongation retention after printing, low shrinkage stress, and printability. It has industrial applicability as materials for beverage container packaging, cap seals, and various labels.

Claims (9)

A multilayer heat-shrinkable film comprising a first layer and a second layer, wherein the first layer and the second layer are laminated,
The first layer is formed of the following block copolymer hydrogenated composition (α),
The second layer is a block copolymer containing a vinyl aromatic hydrocarbon and a conjugated diene hydrocarbon, or a mixed polymer obtained by blending a styrene polymer with the block copolymer, or these Are formed of a mixed polymer comprising two or more different types of block copolymers.
The block copolymer hydrogenated composition (α) is:
Block copolymer hydrogenated product (I): 5 to 90% by mass
Block copolymer or hydrogenated product (II) thereof: 5 to 90% by mass
Olefin resin (III): 5 to 90% by mass
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 85% by mass. The block ratio of the vinyl aromatic hydrocarbon polymer contained in the block copolymer hydrogenated product (I) is 50 to 95% by mass, and the total vinyl aroma in the block copolymer hydrogenated product (I) The aromatic hydrocarbon polymer block has a number average molecular weight of 50,000 to 60,000, and at least one peak temperature of the function tan δ of dynamic viscoelasticity measurement is −40 ° C. or lower, and the vinyl aromatic hydrocarbon And the hydrogenation rate of the double bond of the conjugated diene unit in the block copolymer comprising conjugated diene is 10% or more and less than 50%,
The block copolymer or hydrogenated product (II) thereof is a block copolymer consisting of a vinyl aromatic hydrocarbon and a conjugated diene or a hydrogenated product thereof, and the vinyl aromatic hydrocarbon content is 85% by mass. The block ratio of the vinyl aromatic hydrocarbon polymer contained in the block copolymer or the hydrogenated product (II) thereof is 20 to 95% by mass, The number average molecular weight of the all-vinyl aromatic hydrocarbon polymer block in the coalescence or its hydrogenated product (II) is from 50,000 to 80,000, and the peak temperature of the function tan δ of dynamic viscoelasticity measurement is from 60 to 110 At least one at
The content of the hydrogenated conjugated diene unit in the block copolymer hydrogenated composition (α) is 0.5 to 10% by mass.
Multi-layer heat shrinkable film. The vinyl aromatic hydrocarbon content in the block copolymer hydrogenated product (I) is 58 to 80% 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 multilayer 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 or hydrogenated product (II) thereof 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 or hydrogenated product (II) thereof is 30 to 85% by mass, and the block copolymer or hydrogenated product (II) thereof. The number average molecular weight of the all-vinyl aromatic hydrocarbon polymer block is from 50,000 to 60,000, and at least one peak temperature of the function tan δ of dynamic viscoelasticity measurement exists at 70 to 105 ° C. Or the multilayer heat-shrinkable film of 2.   The content of hydrogenated conjugated diene units in the block copolymer hydrogenated composition (α) is 0.8 to 9% by mass. Multi-layer heat shrinkable film. The multilayer heat-shrinkable film according to any one of claims 1 to 4, wherein the block copolymer hydrogenated composition (α) 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.   Formed with a block copolymer hydrogenated composition (α) containing a total of 50 to 99.9% by mass of the components (I) to (III) and 0.1 to 50% by mass of the component (IV). The multilayer heat-shrinkable film according to claim 5, comprising the first layer formed.   The multilayer heat-shrinkable film according to any one of claims 1 to 6, wherein a content of the vinyl aromatic hydrocarbon in the second layer is 75 to 85% by mass.   The said 2nd layer contains 13-20 mass% of components whose loss elastic modulus (E ") measured with the vibration frequency of 35 Hz is -25 degrees C or less. A multilayer heat-shrinkable film as described in 1.   The multilayer heat-shrinkable film according to any one of claims 1 to 8, further comprising a third layer on a side of the first layer opposite to a surface on which the second layer is formed.