Patent Description:
Block copolymers comprising a vinyl aromatic monomer unit and a conjugated diene monomer unit, which have elasticity comparable to that of vulcanized natural rubber and synthetic rubber at normal temperature, even when not vulcanized, and furthermore have fabricability comparable to that of a thermoplastic resin at high temperatures, are widely used in fields such as footwear, plastic modification, asphalt modification, and adhesive materials, household products, packaging materials for consumer electrical appliances and industrial parts, toys, and the like. The hydrogenated products of the block copolymer, which has excellent weatherability and heat resistance, are widely used also in automotive parts and medical devices in addition to the application fields as aforementioned.

Particularly when used as adhesives, such hydrogenated products are used as hot melts for hygiene products and building material applications, or primarily as labels, tape, or surface protection films by imparting a tacky layer to the film surface. Conventionally, acrylic adhesives, and rubber-based adhesives mainly containing rubbers such as natural rubber and polyisobutylene, are primarily used as adhesives for the tacky layer of such a film. Methods involving applying, with a roll, spray, or the like, an adhesive solution in which an adhesive is dissolved in a solvent are used as methods for applying such an adhesive to a predetermined support film. Although such methods are capable of forming the adhesive layer uniformly and thinly and are thus advantageous, the methods have a problem in that the use of a solvent is not preferable from the viewpoint of air pollution, fire, safety and health during production, economy, and so on.

For such a reason, recently, coextrusion films have been suitably used that integrally includes a substrate layer made of a polyolefin resin and an adhesive layer containing a hydrogenated styrene elastomer or olefinic elastomer.

In these applications, suppression of increase in tackiness and improvement in fabricability are required, in addition to tack strength in accordance with the application. For example, Patent Literature <NUM> describes a tacky film targeted for simultaneously achieving fabricability and tackiness without mixing of a tackifier but does not refer to increase in tackiness, and the film still leaves room for improvement. Patent Literature <NUM> describes a tacky film excellent in initial tackiness, low temperature tackiness, feedability, low increase in tackiness, and balance of the properties, but does not refer to moldability, and the film still leaves room for improvement. Patent Literature <NUM> describes a tacky adhesive composition targeted for initial tack strength, low increase in tackiness, suppression of surface contamination, suppression of adhesive residues, and suppression of zipping, but is characteristic of use of a specific tacky resin compound. Thus, room for improvement still remains in a substantial solution of these problems by the hydrogenated copolymer composition.

<CIT> discloses A hydrogenated block copolymer comprising: a polymer block (S) comprising an aromatic vinyl compound unit as a main constituent; and a polymer block (B) comprising a conjugated diene compound unit as a main constituent, in a molecule, wherein a content of the polymer block (S) is <NUM> to <NUM>% by mass and a content of the polymer block (B) is <NUM> to <NUM>% by mass, in the hydrogenated block copolymer, the polymer block (B) comprises a polymer block (B1) and a polymer block (B2); an amount of a vinyl bond of the polymer block (B1) before hydrogenation is <NUM> to <NUM> mol% and an amount of a vinyl bond of the polymer block (B2) before hydrogenation is more than <NUM> to <NUM> mol%, a content of the polymer block (B1) is <NUM> to <NUM>% by mass and a content of the polymer block (B2) is <NUM> to <NUM>% by mass, in the hydrogenated block copolymer, a content of a structure represented by the formula (S-B) in the hydrogenated block copolymer is <NUM> to <NUM>% by mass, and a hydrogenation rate of the hydrogenated block copolymer is <NUM> mol% or more.

According to the research of the present inventors, uneven thicknesses of the tacky layer are not only regarded as a problem during fabrication but also affect tack strength and increase in tackiness. Uneven thicknesses of the tacky layer may lead to lifting of the film, adhesive residues, and zipping during peeling, and thus, suppression of such uneven thicknesses is particularly important. In respect of a combination of initial tack strength, suppression of increase in tackiness, and suppression of uneven thicknesses of a tacky layer in a highly well-balanced manner, conventional resin compositions still leave room for improvement.

In view of the aforementioned problems of conventional art, an object of the present invention is to provide an adhesive material composition, and an adhesive film having an excellent balance among initial tack strength, suppression of increase in tackiness, and suppression of uneven thicknesses of a tacky layer, when used as an adhesive material.

In order to solve the above problems of conventional art, the inventors have conducted diligent research and, as a result, have found that the use of a hydrogenated copolymer composition including two components each having a specific structure in an adhesive composition effectively solves the above problems, having accomplished the present invention.

That is to say, the present invention is as set out in the appended claims.

According to the present invention, there can be provided an adhesive material composition, and an adhesive film having a highly excellent balance among initial tack strength, suppression of increase in tackiness, and suppression of uneven thicknesses of a tacky layer, when used as a tacky adhesive material.

Hereinafter, an embodiment for carrying out the present invention (hereinafter referred to as "the present embodiment") will now be described in detail, but the present invention is not limited to the following embodiment, and can be performed after making various modifications within the scope of the claims.

A hydrogenated copolymer composition used in the present embodiment comprises:.

In the present embodiment, each monomer unit constituting the copolymer is named after the monomer from which the monomer unit is derived.

For example, the "vinyl aromatic monomer unit" means a constitutional unit of a polymer produced as a result of polymerizing a monomer vinyl aromatic compound. The vinyl aromatic monomer unit is bonded to other monomer units via the vinyl groups of the vinyl aromatic compound.

Moreover, the "conjugated diene monomer unit" means a constitutional unit of a polymer produced as a result of polymerizing a monomer conjugated diene compound. The conjugated diene monomer unit is bonded to other monomer units via one of the two double bonds of the conjugated diene compound (<NUM>,<NUM>-bond or <NUM>,<NUM>-bond) or bonded to other monomer units via both the two double bonds of the conjugated diene compound (<NUM>,<NUM>-bond).

The hydrogenated copolymer composition of the present embodiment comprises the component (a) and the component (b). The total content of the component (a) and the component (b) is preferably <NUM> mass% or more, more preferably <NUM> mass% or more, and yet more preferably <NUM> mass% based on the hydrogenated copolymer composition.

The component (a) comprises a polymer block A comprising a vinyl aromatic monomer unit as a main component and a polymer block B comprising a conjugated diene monomer unit as a main component. The component (a) may comprise one or more polymer blocks A and one or more polymer blocks B.

The content of the polymer block A included in the component (a) is preferably <NUM> to <NUM> mass%, more preferably <NUM> to <NUM> mass%, and yet more preferably <NUM> to <NUM> mass% based on the component (a).

The content of the polymer block B included in the component (a) is preferably <NUM> to <NUM> mass%, more preferably <NUM> to <NUM> mass%, and yet more preferably <NUM> to <NUM> mass% based on the component (a).

The total content of the polymer block A and the polymer block B included in the component (a) is preferably <NUM> mass% or more, more preferably <NUM> mass% or more, and yet more preferably <NUM> mass% based on the component (a).

The polymer block A included in the component (a) comprises a vinyl aromatic monomer unit as a main component. The amount of the vinyl aromatic monomer unit included in the polymer block A is <NUM> mass% or more, preferably <NUM> mass% or more, and more preferably <NUM> mass% or more based on the polymer block A.

The polymer block B included in the component (a) comprises a conjugated diene monomer unit as a main component. The amount of the conjugated diene monomer unit included in the polymer block B is <NUM> mass% or more, preferably <NUM> mass% or more, and more preferably <NUM> mass% or more based on the polymer block B.

The component (b) comprises a polymer block A comprising a vinyl aromatic monomer unit as a main component and a polymer block B comprising a conjugated diene monomer unit as a main component. The polymer block A and the polymer block B included in the component (b) each may be the same as or different from the polymer block A and the polymer block B included in the component (a). The component (b) may comprise one or more polymer blocks A and one or more polymer blocks B.

The content of the polymer block A included in the component (b) is preferably <NUM> to <NUM> mass%, more preferably <NUM> to <NUM> mass%, and yet more preferably <NUM> to <NUM> mass% based on the component (b).

The content of the polymer block B included in the component (b) is preferably <NUM> to <NUM> mass%, more preferably <NUM> to <NUM> mass%, and yet more preferably <NUM> to <NUM> mass% based on the component (b).

The total content of the polymer block A and the polymer block B included in the component (b) is preferably <NUM> mass% or more, more preferably <NUM> mass% or more, and yet more preferably <NUM> mass% based on the component (b).

The polymer block A included in the component (b) comprises a vinyl aromatic monomer unit as a main component. The amount of the vinyl aromatic monomer unit included in the polymer block A is <NUM> mass% or more, preferably <NUM> mass% or more, and more preferably <NUM> mass% or more based on the polymer block A.

The polymer block B included in the component (b) comprises a conjugated diene monomer unit as a main component. The amount of the conjugated diene monomer unit included in the polymer block B is <NUM> mass% or more, preferably <NUM> mass% or more, and more preferably <NUM> mass% or more based on the polymer block B.

Examples of the "vinyl aromatic compound" constituting the "vinyl aromatic monomer unit" include, but are not limited to, styrene, α-methylstyrene, p-methylstyrene, divinylbenzene, <NUM>,<NUM>-diphenylethylene, N,N-dimethyl-p-aminoethylstyrene, and N,N-diethyl-p-aminoethylstyrene. Of these, styrene, α-methylstyrene and p-methylstyrene are preferred from the viewpoint of availability and productivity. Of these, styrene is particularly preferred. Only one of these may be used singly, and two or more of these may be used in combination.

The "conjugated diene compound" constituting the "conjugated diene monomer unit" is a diolefin having a pair of conjugated double bonds. Examples of the conjugated diene compound include, but are not limited to, <NUM>,<NUM>-butadiene, <NUM>-methyl-<NUM>,<NUM>-butadiene (isoprene), <NUM>,<NUM>-dimethyl-<NUM>,<NUM>-butadiene, <NUM>,<NUM>-pentadiene, <NUM>-methyl-<NUM>,<NUM>-pentadiene, <NUM>,<NUM>-hexadiene, and Farnesene. Examples of preferred diolefins include <NUM>,<NUM>-butadiene and isoprene. Only one of these may be used singly, and two or more of these may be used in combination.

The peak top molecular weight of the component (a) is <NUM>,<NUM> to <NUM>,<NUM>, preferably <NUM>,<NUM> to <NUM>,<NUM>, and more preferably <NUM>,<NUM> to <NUM>,<NUM>. When the peak top molecular weight of the component (a) is <NUM>,<NUM> or more, excellent suppression of increase in tackiness and fabricability are provided. When the peak top molecular weight of the component (a) is <NUM>,<NUM> or less, excellent tackiness and fabricability are provided. The peak top molecular weight can be determined by obtaining a molecular weight corresponding to the top of the peak obtained by gel permeation chromatography (GPC) (solvent: tetrahydrofuran, temperature: <NUM>) from a standard polystyrene calibration curve.

The peak top molecular weight of the component (b) is <NUM> times to <NUM> times, preferably <NUM> times to <NUM> times, more preferably <NUM> times to <NUM> times, yet more preferably <NUM> times to <NUM> times the peak top molecular weight of the component (a). When the peak top molecular weight of the component (b) is in the above range, excellent fabricability is provided.

The component (a)/component (b) in terms of mass proportion is preferably <NUM>/<NUM> to <NUM>/<NUM>, more preferably <NUM>/<NUM> to <NUM>/<NUM>, and yet more preferably <NUM>/<NUM> to <NUM>/<NUM>. When the mass proportion of the component (b) is <NUM> or more, excellent tack strength and suppression of increase in tackiness are provided. When the mass proportion of the component (b) is <NUM> mass or less, excellent fabricability is provided.

A method for obtaining a hydrogenated copolymer composition comprising the component (a) and the component (b) is not particularly limited. For example, the component (a) and the component (b) are each polymerized and hydrogenated, and the hydrogenated polymers may be solution-blended or dry-blended at an appropriate ratio. From the viewpoint of productivity, it is preferred that the component (a) be polymerized, a portion of the component (a) be subjected to a coupling reaction to form the component (b), a copolymer composition comprising the component (a) and the component (b) be obtained at once, and the composition be hydrogenated.

A coupling agent is not particularly limited as long as the above peak top molecular weights and mass proportions of the component (a) and the component (b) are achieved, and examples of the coupling agent include polyalkenyl coupling agents. Preferred exemplary polyalkenyl coupling agents are divinylbenzenes, and m-divinylbenzene is preferred. Examples of the coupling agent also include tetraalkoxysilanes such as tetraethoxysilane and tetramethoxysilane, alkyltrialkoxysilanes such as methyltrimethoxysilane, dialkyldialkoxysilanes such as dimethyldimethoxysilane, carboxylic acid ester compounds such as ethyl benzoate and methyl benzoate, and glycidyl aromatic epoxy compounds such as a diglycidyl ether derived from a reaction between bisphenol A and epichlorohydrin.

The component (a) and the component (b) are preferably each independently represented by the following formulas.

A1-B1, B2-A1-B1, A1-B1-A2, B2-A1-B1-A2, B2-A1-B1-X, (A1-B1)nX, or (B2-A1-B1)nX:.

From the viewpoint of tack strength, suppression of increase in tackiness, and fabricability, the component (a) and/or component (b) preferably have a coupling structure. From the viewpoint of satisfying the relation (<NUM>) between capillary viscosity and melt flow rate mentioned below and from the viewpoint of highly achieving the balance among tack strength, suppression of increase in tackiness, and fabricability, the component (a) preferably has a structure represented by B2-A1-B1 and/or B2-A1-B1-X, and the component (b) preferably has a structure represented by (B2-A1-B1)nX.

n is preferably an integer of <NUM> to <NUM> and more preferably <NUM> or <NUM>. For example, n can be controlled to <NUM> or <NUM> by using tetraethoxysilane as the coupling agent and adjusting the stirring time at a temperature at addition of <NUM> or less under a condition of a stirrer such as a paddle blade.

When the component (a) and/or component (b) include B2, from the viewpoint of fabricability, the content of B2 is preferably <NUM> to <NUM> mass% based on the hydrogenated copolymer composition. When the content of B2 is <NUM>% or less, excellent suppression of increase in tackiness tends to be provided.

The content of the vinyl aromatic monomer unit in the hydrogenated copolymer composition is <NUM> to <NUM> mass%, preferably <NUM> to <NUM> mass%, and more preferably <NUM> to <NUM> mass% based on the composition. When the content of the vinyl aromatic monomer unit is <NUM> mass% or less, the tackiness and fabricability become better. When the content of the vinyl aromatic monomer unit is <NUM> mass% or more, the increase in tackiness can be suppressed, and the fabricability also tends to become better.

The content of the vinyl aromatic monomer unit in the hydrogenated copolymer composition can be measured with an ultraviolet spectrophotometer as described in Examples described below. The content of the vinyl aromatic monomer unit is nearly identical before and after hydrogenation, and therefore the content of the vinyl aromatic monomer unit in the copolymer before hydrogenation may be relied upon.

The content of the vinyl aromatic monomer unit in the hydrogenated copolymer composition can be controlled within the predetermined numeric range by adjusting the amount of the vinyl aromatic compound added in the polymerization step.

The content of the vinyl aromatic monomer block in the hydrogenated copolymer composition based on the content of all the vinyl aromatic monomer units in the hydrogenated copolymer composition is referred to as the "vinyl aromatic monomer block content" or to as simply the "block content". The vinyl aromatic monomer block is a group of three or more sequential vinyl aromatic monomer units, and the signal of the block can be detected by <NUM>H-NMR. The block content of the hydrogenated copolymer composition is <NUM> mass% or more, preferably <NUM> mass% or more, and more preferably <NUM> mass% or more. When the block content is <NUM> mass% or more, excellent suppression of increase in tackiness and fabricability tend to be provided. The block content can be measured with <NUM>H-NMR as described in Examples.

The content of the conjugated diene monomer unit in the hydrogenated copolymer composition is preferably <NUM> to <NUM> mass%, more preferably <NUM> to <NUM> mass%, and yet more preferably <NUM> to <NUM> mass% based on the composition.

In the hydrogenated copolymer composition, the conjugated diene monomer unit is incorporated via a binding mode of a <NUM>,<NUM>-bond, <NUM>,<NUM>-bond, or <NUM>,<NUM>-bond in the copolymer. The total proportion of the conjugated diene monomer units incorporated via a binding mode of a <NUM>,<NUM>-bond or <NUM>,<NUM>-bond is preferably <NUM> to <NUM> mol% and more preferably <NUM> to <NUM> mol% based on the total of the conjugated diene monomer units incorporated via the binding mode of the <NUM>,<NUM>-bond, <NUM>,<NUM>-bond, or <NUM>,<NUM>-bond. The conjugated diene monomer units incorporated via a binding mode of the <NUM>,<NUM>-bond or <NUM>,<NUM>-bond each has a vinyl group. Thus, the total proportion of the conjugated diene monomer units incorporated via a binding mode of the <NUM>,<NUM>-bond or <NUM>,<NUM>-bond is referred to as a "vinyl bond content". When the vinyl bond content is <NUM> mol% or more, excellent initial tack strength is provided, practically effective tackiness can be developed, and excellent fabricability is provided. When the vinyl bond content is <NUM> mol% or less, excellent suppression of increase in tackiness tends to be provided.

The vinyl bond content can be controlled by using a Lewis base as a vinylating agent (e.g., an ether or an amine), its amount of use, and the polymerization temperature. The vinyl bond content can be measured by nuclear magnetic resonance spectrum analysis (<NUM>H-NMR). The vinyl bond content may be measured either before or after hydrogenation. Specifically, the vinyl bond content can be measured by the method described in the Examples below.

Double bonds of the conjugated diene monomer units included in the hydrogenated copolymer composition are hydrogenated. The proportion of the hydrogenated double bonds of the conjugated diene monomer units (hereinafter the "degree of hydrogenation") is <NUM> mol% or more, preferably <NUM> mol% or more, and more preferably <NUM> mol% or more. When the degree of hydrogenation is <NUM>% or more, increase in tackiness can be suppressed, excellent fabricability can be provided, degradation on molding also can be suppressed, and gelling can be suppressed.

The degree of hydrogenation can be controlled by adjusting the amount of catalyst and the amount of hydrogen to be fed during hydrogenation, for example. The hydrogenation speed can be controlled by adjusting the amount of catalyst, the amount of hydrogen to be fed, the pressure and temperature during hydrogenation, for example. The degree of hydrogenation can be measured by the method described in the Examples below.

The melt flow rate (hereinafter, also referred to as "MFR", in accordance with ISO <NUM>) of the hydrogenated copolymer composition of the present embodiment is <NUM> to <NUM>/<NUM>, preferably <NUM> to <NUM>/<NUM>, and yet more preferably <NUM> to <NUM>/<NUM> under conditions of a temperature of <NUM> and a load of <NUM>. When the MFR is <NUM>/<NUM> or less, an excellent balance between the tack strength and the suppression of increase in tackiness is provided. When the MFR is <NUM>/<NUM> or more, excellent fabricability is provided.

The MFR of the hydrogenated copolymer composition can be controlled by adjusting the polymerization conditions such as the amount of monomer added, polymerization time, temperature, and polymerization initiator and can be measured by a method described in Examples described below.

The capillary rheometer measurement viscosity (hereinafter, also referred to as the "capillary viscosity") of the hydrogenated copolymer composition is <NUM> to <NUM> Pa·s, preferably <NUM> to <NUM> Pa·s, and yet more preferably <NUM> to <NUM> Pa·s under conditions of a temperature of <NUM> and a shear rate of <NUM> sec-<NUM>. This capillary viscosity is a value obtained by measurement in compliance with ISO11443, but is a so-called "apparent viscosity", which has not been subjected to the Bagley correction or the Rabinovitch correction. Since the measurement value greatly depends on measurement apparatus conditions, the measurement apparatus conditions are specified as follows. The accuracy of the numerical values below and conditions not specified below are compliant to ISO <NUM>.

When the capillary viscosity is <NUM> Pa·s or less, excellent fabricability is provided. When the capillary viscosity is <NUM> Pa·s or more, an excellent balance between the tack strength and the suppression of increase in tackiness is provided.

The capillary viscosity of the hydrogenated copolymer composition can be controlled by adjusting the polymerization conditions such as the amount of monomer added, polymerization time, temperature, and polymerization initiator and can be measured by a method described in Examples described below.

The capillary viscosity (C) and the MFR (M) of the hydrogenated copolymer composition satisfy the relationship of the following expression (<NUM>):<MAT> The expression (<NUM>) is derived as a result of a detailed investigation on the relationship between the capillary viscosity and MFR and the fabricability of a plurality of hydrogenated copolymer compositions. Both the MFR and the capillary viscosity are indicators of the viscosity and naturally correlated with each other. While the MFR reflects low shearing, the capillary viscosity is considered to reflect a viscosity at high shearing with the conditions set constant (temperature: <NUM>, shear rate: <NUM> sec-<NUM>). In the present invention, with attention focused on the fact that high shearing is imparted during fabrication of the composition, it is considered that lowering the capillary viscosity may suppress the uneven thicknesses due to fabrication. Meanwhile, the environment to be used after film molding is close to the conditions under which low shearing is provided, and it is considered that, with a lower MFR, the tack strength is higher and the increase in tackiness is more unlikely to occur. Satisfying the relationship of the expression (<NUM>) means that the capillary viscosity, which is a dynamic viscosity indicator, is a low value which may not be provided by conventional design, with respect to the MFR, which is a static viscosity indicator. Simultaneously achieving the MFR and the relationship of the expression (<NUM>) allows the viscosities at low shearing and high shearing to satisfy preferred ranges as described above. Thus, the fabricability of the hydrogenated copolymer composition and the balance between the tack strength and the suppression of increase in tackiness of the adhesive film are excellent. Specifically, for example, in coextrusion molding using a film extruder, uneven thicknesses are unlikely occur in the tacky layer, and the tack strength and the suppression of increase in tackiness of the adhesive film are well-balanced.

In order to satisfy the above expression (<NUM>), it is necessary to have a specific polymer structure, and it is necessary to fulfill the following requirements:.

A plurality of vinyl aromatic monomer blocks is provided in the molecule within the range of the vinyl aromatic monomer amount, and the chain length of the vinyl aromatic monomer blocks is changed.

Thereby, a vinyl aromatic monomer block (large) and a vinyl aromatic monomer block (small) may be formed in one identical molecular chain. The vinyl aromatic monomer block (small) has a large contribution to the viscosity at low shearing as in MFR measurement, and thus, the viscosity is kept high. In contrast, the vinyl aromatic monomer block (small) has a relatively smaller influence on the viscosity at high shearing as the capillary viscosity, and thus, the viscosity becomes lower. Consequently, it can be expected that only the capillary viscosity will be lowered while MFR is maintained.

The styrene block (large) is preferably set to have a molecular weight of about <NUM>,<NUM> to <NUM>,<NUM> which is also <NUM> times to <NUM> times the molecular weight of the styrene block (small), although depending on the molecular weight, the degree of hydrogenation, and the like.

Mixed are two or more polymers in which the size of the vinyl aromatic monomer block is different among different molecules (the vinyl aromatic monomer blocks in one identical molecular chain have the same size).

As in Design Example <NUM>, an effect in that the viscosity at high shearing is different from the viscosity at low shearing is expected due to the influence of the vinyl aromatic monomer blocks each having a different size.

A special functional group that allows a molecular chain to be once dissociated (cleaved) under high shearing conditions as the capillary viscosity and then to be restored is introduced into the molecular chain. Thereby, there can be expected an effect of lowering only the viscosity at high shearing while the viscosity at low shearing is maintained. Examples of a functional group that may exert this effect include a non-covalent functional group such as a hydroxyl group, an amino group, a carboxyl group, an amide group, a urea group, an imide group, and a guanidino group.

If the tacky layer has uneven thicknesses, the tack strength is affected because the ratio of the layer thickness with respect to the substrate layer changes to thereby lead to a change in a stress applied on a peel portion during peeling. Similarly, the change in the ratio of the layer thickness with respect to the substrate layer also leads to a change in the strength of the substrate layer portion for retaining the tacky layer, and thus, the increase in tackiness is affected. In addition, zipping, an adhesive residue, and lifting of the film are affected for the similar reasons.

The hydrogenated copolymer composition can be produced, for example, by carrying out polymerization in an organic solvent with an organic alkali metal compound as the polymerization initiator to obtain a copolymer and then subjecting the copolymer to hydrogenation.

The polymerization form may be batch polymerization or continuous polymerization, or may be a combination thereof. From the viewpoint of obtaining a copolymer having a narrow molecular weight distribution, a batch polymerization method is preferred.

The polymerization temperature is generally <NUM> to <NUM>, preferably <NUM> to <NUM>, more preferably <NUM> to <NUM>, and even more preferably <NUM> to <NUM>.

The polymerization time depends on the polymer intended, and is usually with <NUM> hours and preferably <NUM> to <NUM> hours. From the viewpoint of obtaining a copolymer having a narrow molecular weight distribution and high strength, the polymerization time is more preferably <NUM> to <NUM> hours.

The atmosphere of the polymerization system, which is not particularly limited, is only required to be in a pressure range sufficient maintaining nitrogen and the solvent in a liquid phase.

The polymerization system preferably includes no impurities such as water, oxygen and carbon dioxide, which may deactivate the polymerization initiator and the living polymer.

Examples of the organic solvent include, but are not particularly limited to, aliphatic hydrocarbons, such as n-butane, isobutane, n-pentane, n-hexane, n-heptane, and n-octane; alicyclic hydrocarbons, such as cyclohexane, cycloheptane, and methylcyclopentane; and aromatic hydrocarbons, such as benzene, xylene, toluene, and ethylbenzene.

The organic alkali metal compound as the polymerization initiator is preferably an organic lithium compound.

As the organic lithium compound, organic monolithium compounds, organic dilithium compounds, and organic polylithium compounds can be used. Examples of the organic lithium compound include, but are not limited to, ethyllithium, n-propyllithium, isopropyllithium, n-butyllithium, sec-butyllithium, t-butyllithium, phenyllithium, hexametylenedilithium, butadienyllithium, and isopropenyldilithium. Of these, from the viewpoint of polymerization activity, n-butyllithium and sec-butyllithium are preferred.

The amount of the organic alkali metal compound used as the polymerization initiator depends on the molecular weight of the polymer intended, and is generally in the range of <NUM> to <NUM> phm (parts by mass per <NUM> parts by mass of the monomer), preferably in the range of <NUM> to <NUM> phm, and more preferably in the range of <NUM> to <NUM> phm.

The total amount of the <NUM>,<NUM>-bonds and <NUM>,<NUM>-bonds of the conjugated diene monomer unit in the hydrogenated copolymer composition can be controlled by using a Lewis base (e.g., an ether or an amine) as a vinylating agent. The amount of the vinylating agent used is adjusted in accordance with the amount of vinyl bonds intended. Alternatively, adding the vinylating agent and a metal alkoxide described below separately under two or more conditions can produce a polymer having a different amount of vinyl bonds in a polymer comprising a conjugated diene monomer unit as a main component.

Examples of the vinylating agent include, but are not limited to, ether compounds, etheric compounds having two or more oxygen atoms, and tertiary amine compounds.

Examples of the tertiary amine compound include, but are not limited to, pyridine, N,N,N',N'-tetramethylethylenediamine, tributylamine, tetramethylpropanediamine, <NUM>,<NUM>-dipiperidinoethane, and bis[<NUM>-(N,N-dimethylamino)ethyl]ether. Only one of these may be used singly, and two or more of these may be used in combination.

Preferable tertiary amine compounds are compounds having two amines. Furthermore, of these, compounds having a structure showing symmetry in the molecule are more preferable, and N,N,N',N'-tetramethylethylenediamine, bis[<NUM>-(N,N-dimethylamino)ethyl]ether, and <NUM>,<NUM>-dipiperidinoethane are even more preferable.

In the production step for the hydrogenated copolymer composition, polymerization may be performed under coexistence of the vinylating agent, organic lithium compound, and alkali metal alkoxide aforementioned. The alkali metal alkoxide herein is a compound represented by the general formula MOR, wherein M is an alkali metal, and R is an alkyl group.

The alkali metal of the alkali metal alkoxide is preferably sodium or potassium from the viewpoint of a high amount of vinyl bond, a narrow molecular weight distribution, a high polymerization speed, and a high block content.

The alkali metal alkoxide is, but are not limited to, preferably a sodium alkoxide, lithium alkoxide, or potassium alkoxide having an alkyl group having <NUM> to <NUM> carbon atoms, more preferably a sodium alkoxide or potassium alkoxide having <NUM> to <NUM> carbon atoms, and even more preferably sodium-t-butoxide, sodium-t-pentoxide, potassium-t-butoxide, or potassium-t-pentoxide.

Of these, sodium alkoxides such as sodium-t-butoxide and sodium-t-pentoxide are still even more preferable.

In the production step of the hydrogenated copolymer composition of the present embodiment, when polymerization is performed under coexistence of a vinylating agent, an organic lithium compound, and an alkali metal alkoxide, the components preferably coexist in the molar ratio of the vinylating agent to the organic lithium compound (vinylating agent/organic lithium compound) and the molar ratio of the alkali metal alkoxide to the organic lithium compound (alkali metal alkoxide/organic lithium compound) described below:.

The molar ratio of vinylating agent/organic lithium compound in the polymerization step is more preferably <NUM> or more from the viewpoint of the high amount of vinyl bonds, and high polymerization speed and is preferably <NUM> or less and more preferably <NUM> or more and <NUM> or less from the viewpoint of the narrow molecular weight distribution and high hydrogenation activity.

The molar ratio of alkali metal alkoxide/organic lithium compound is more preferably <NUM> or less, even more preferably <NUM> or less, and even more preferably <NUM> or less from the viewpoint of the narrow molecular weight distribution and high hydrogenation activity.

Furthermore, the molar ratio of alkali metal alkoxide/vinylating agent is more preferably <NUM> or less, even more preferably <NUM> or less, still even more preferably <NUM> or less, still even more preferably <NUM> or less from the viewpoint of achieving a narrow molecular weight distribution and obtaining high hydrogenation activity.

When a polymer comprising a conjugated diene monomer unit as a main component is contained in the hydrogenated copolymer composition, an example of an approach to produce a polymer having a different amount of vinyl bonds in the polymer comprising a conjugated diene monomer unit as a main component is a method including use of a deactivator for the vinylating agent.

Examples of the deactivator include, but are not limited to alkyl metal compounds, and the deactivator is selected from alkyl aluminum, alkyl zinc, and alkyl magnesium having <NUM> to <NUM> carbon atoms per alkyl substituent, and mixtures thereof.

In the production step of the hydrogenated copolymer composition, the hydrogenation method is not particularly limited. For example, hydrogenating a copolymer obtained as described above by supplying hydrogen in the presence of a hydrogenation catalyst can provide a hydrogenated copolymer in which the double bond residues of the conjugated diene monomer unit have been hydrogenated.

Additionally, pelletizing the hydrogenated copolymer composition obtained as described above can produce pellets of the hydrogenated copolymer composition.

Examples the pelletizing method include a method including extruding the hydrogenated copolymer in a strand form from a single screw or twin screw extruder and cutting the extruded product in water with a rotary blade installed at the front face of a die portion; a method including extruding the hydrogenated copolymer composition in a strand form from a single screw or twin screw extruder and cutting the extruded product with a strand cutter after water cooling or air cooling; and a method including shaping the hydrogenated copolymer or the hydrogenated copolymer composition into a sheet form with a roll after melt blending with an open roll and a Banbury mixer, further, cutting the sheet into strips, and thereafter cutting the strips into cuboidal pellets with a pelletizer.

It is to be noted that the size and shape of a pellet molded article of the hydrogenated copolymer composition are not particularly limited.

An antiblocking agent for pellets can be blended as necessary in the hydrogenated copolymer composition of the present embodiment in the pellet thereof, as required, in order to prevent blocking of pellets.

Examples of the antiblocking agent for pellets include, but not limited to, calcium stearate, magnesium stearate, zinc stearate, polyethylene, polypropylene, ethylenebis(stearylamide), talc, and amorphous silica.

From the viewpoint of the tackiness of an adhesive film obtained by molding the hydrogenated copolymer composition, the antiblocking agent for pellets is preferably polyethylene, ethylenebis(stearylamide), or calcium stearate.

The amount of the antiblocking agent for pellets blended is preferably <NUM> to <NUM>,<NUM> ppm with respect to the hydrogenated copolymer composition and more preferably <NUM>,<NUM> to <NUM>,<NUM> ppm with respect to the hydrogenated copolymer composition. Although the antiblocking agent for pellets is preferably blended while being attached to the surface of the pellets, a portion of the agent may be contained inside the pellets.

The adhesive material composition of the present embodiment comprises the hydrogenated copolymer composition.

The adhesive material composition of the present embodiment comprises a tackifier.

The tackifier is not particularly limited as long as it is a resin that is capable of imparting viscosity to the adhesive material composition of the present embodiment, and examples include known tackifiers such as rosin terpene resins, hydrogenated rosin terpene resins, cumarone resins, terpene resins, hydrogenated terpene resins, phenol resins, terpene-phenol resins, aromatic hydrocarbon resins, and aliphatic hydrocarbon resins.

Only one tackifier may be used singly, or two or more these may be used as a mixture.

Specific examples of usable tackifiers are those described in "Chemicals for Rubber/Plastics" (by Rubber Digest, Co. Use of a tackifier can improve the tack strength.

The content of the tackifier in the adhesive material composition of the present embodiment is preferably <NUM> parts by mass or less, more preferably <NUM> parts by mass or less, and even more preferably <NUM> parts by mass or less, based on the total mass of the hydrogenated copolymer composition being <NUM> parts by mass.

When the tackifier content is <NUM> parts by mass or less, there is a tendency that increase in tackiness can be effectively suppressed, and therefore such a tackifier content is preferable.

The adhesive material composition of the present embodiment may further comprise a hydrogenated styrenic elastomer having a structure different from that of the above-described hydrogenated copolymer composition of the present embodiment.

The hydrogenated styrene elastomer is not limited to the following, and examples of typical hydrogenated styrenic elastomers include styrene-butadiene-styrene (SBS), styrene-ethylene-butylene-styrene (SEBS) obtained by saturating styrene-isoprene-styrene by hydrogenation, and styrene-ethylene-propylene-styrene (SEPS).

Additional examples include elastomers of such a structure as styrene-ethylene-butylene (SEB) or styrene-ethylene-propylene (SEP).

Moreover, reactive elastomers may be used, which are obtained by adding a variety of functional groups to the above hydrogenated styrenic elastomers.

Examples of the functional group include, but are not limited to, a hydroxyl group, a carboxyl group, a carbonyl group, a thiocarbonyl group, an acid halide group, an acid anhydride group, a thiocarboxylic acid group, an aldehyde group, a thioaldehyde group, a carboxylic acid ester group, an amide group, a sulfonic acid group, a sulfonic acid ester group, a phosphoric acid group, a phosphoric acid ester group, an amino group, an imino group, a nitrile group, a pyridyl group, a quinoline group, an epoxy group, a thioepoxy group, a sulfide group, an isocyanate group, an isothiocyanate group, a silicon halide group, an alkoxy silicon group, a tin halide group, a boronic acid group, a boron-containing group, a boronic acid salt group, an alkoxy tin group, and a phenyl tin group.

The adhesive material composition of the present embodiment may further comprise an ethylene vinyl acetate copolymer.

The ethylene vinyl acetate copolymer can be produced, for example, by subjecting ethylene and vinyl acetate to radical copolymerization under high-temperature, highpressure conditions, but the production method is not particularly limited. Although the properties of the ethylene vinyl acetate copolymer depend on the vinyl acetate content, the vinyl acetate content is not particularly limited.

The adhesive material composition of the present embodiment may further comprise an acrylic copolymer.

Examples of the acrylic copolymer include, but are not particularly limited to, copolymers of methyl acrylate, ethyl acrylate, methyl methacrylate, acrylnitrile, with vinyl acetate, vinyl chloride, styrene.

The adhesive material composition of the present embodiment may further comprise a softening agent.

Examples of the softening agent include, but are not limited to, mineral-oil softening agents and synthetic-resin softening agents.

In general, examples of mineral-oil softening agents include mixtures of aromatic hydrocarbons, naphthenic hydrocarbons, and paraffinic hydrocarbons. Oils in which carbon atoms of paraffinic hydrocarbons account for <NUM>% or more of all carbon atoms are referred to as paraffinic oils, oils in which carbon atoms of naphthenic hydrocarbons account for <NUM> to <NUM>% are referred to as naphthenic oils, and oils in which carbon atoms of aromatic hydrocarbons account for <NUM>% or more are referred to as aromatic oils.

Paraffinic oils, which are softening agents for rubbers, are preferable as mineral-oil softening agents, and polybutene and low molecular weight polybutadiene are preferable as synthetic-resin softening agents.

When a softening agent is contained, the adhesive material composition of the present embodiment tends to have more improved tackiness.

From the viewpoint of suppressing the bleeding of a softening agent and ensuring practically sufficient tack strength in the adhesive material composition of the present embodiment, the softening agent content in the adhesive material composition of the present embodiment is preferably <NUM> parts by mass or less and more preferably <NUM> parts by mass or less based on the mass of the hydrogenated copolymer composition of the present embodiment being <NUM> parts by mass.

Furthermore, a stabilizer such as an antioxidant or a light stabilizer may be added to the adhesive material composition of the present embodiment.

Examples of the antioxidant include, but are not limited to, hindered phenol antioxidants such as <NUM>,<NUM>-dit-butyl-<NUM>-methylphenol, n-octadecyl-<NUM>-(<NUM>'-hydroxy-<NUM>',<NUM>'-di-t-butylphenyl)propionate, <NUM>,<NUM>'-methylenebis(<NUM>-methyl-<NUM>-t-butylphenol), <NUM>,<NUM>'-methylenebis(<NUM>-ethyl-<NUM>-t-butylphenol), <NUM>,<NUM>-bis[(octylthio)methyl]-o-cresol, <NUM>-t-butyl-<NUM>-(<NUM>-t-butyl-<NUM>-hydroxy-<NUM>-methylbenzyl)-<NUM>-methylphenyl acrylate, <NUM>,<NUM>-di-t-amyl-<NUM>-[<NUM>-(<NUM>,<NUM>-di-t-amyl-<NUM>-hydroxyphenyl)ethyl]phenyl acrylate, and <NUM>-[<NUM>-(<NUM>-hydroxy-<NUM>,<NUM>-di-tert-pentylphenyl)] acrylate; sulfur antioxidants such as dilauryl thiodipropionate and lauryl stearyl thiodipropionate pentaerythritol-tetrakis(β-lauryl thiopropionate); and phosphorus antioxidants such as tris(nonylphenyl) phosphite and tris(<NUM>,<NUM>-di-t-butylphenyl) phosphite.

Examples of the light stabilizer include, but are not limited to, benzotriazole ultraviolet absorbers such as <NUM>-(<NUM>'-hydroxy-<NUM>'-methylphenyl)benzotriazole, <NUM>-(<NUM>'-hydroxy-<NUM>',<NUM>'-t-butylphenyl)benzotriazole, and <NUM>-(<NUM>'-hydroxy-<NUM>',<NUM>'-di-t-butylphenyl)-<NUM>-chlorobenzotriazole; benzophenone ultraviolet absorbers such as <NUM>-hydroxy-<NUM>-methoxybenzophenone; and hindered amine light stabilizers.

In addition to the above-described various materials, various additives may be added to the adhesive material composition of the present embodiment as necessary.

Examples of such additives include, but are not limited to, pigments such as iron red and titanium dioxide; waxes such as paraffin wax, microcrystalline wax, and low molecular weight polyethylene wax; polyolefin or low molecular weight vinylaromatic thermoplastic resins such as amorphous polyolefin and ethylene ethyl acrylate copolymers; natural rubbers; and synthetic rubbers such as polyisoprene rubber, polybutadiene rubber, styrene-butadiene rubber, ethylene-propylene rubber, chloroprene rubber, acrylic rubber, isoprene-isobutylene rubber, and polypentenamer rubber.

Specific examples of the synthetic rubbers include those described in "Chemicals for Rubber/Plastics" (by Rubber Digest, Co.

The method for producing the adhesive material composition of the present embodiment is not particularly limited, and the adhesive material composition can be produced by conventionally known methods.

Examples of the method for producing the adhesive material composition include melt kneading methods involving a commonly used mixer such as a Banbury mixer, a single screw extruder, a twin screw extruder, a co-kneader, or a multiscrew extruder; and methods in which components are dissolved or dispersion-mixed, then applied to a predetermined substrate film with a coater, and heated to remove the solvent.

Foaming treatment may be performed on the adhesive material composition of the present embodiment to reduce weight, provide flexibility, and improve adhesion.

Examples of foaming treatment methods include, but are not limited to, chemical methods, physical methods, and the use of thermally expandable microballoons. Such methods can each distribute voids in a material, for example, by adding a chemical blowing agent, such as an inorganic blowing agent or an organic blowing agent, or a physical blowing agent or by adding thermally expandable microballoons. Moreover, a hollow filler (expanded balloons) may also be added to reduce weight, provide flexibility, and improve adhesion.

The adhesive film of the present embodiment comprises the adhesive material composition of the present embodiment.

The adhesive film of the present embodiment is preferably configured to include a tacky layer formed by laminating the hydrogenated copolymer composition or the adhesive material composition described in the above embodiment on a predetermined substrate film.

The material of the substrate film is not particularly limited, and any non-polar resins and polar resins can be used. In terms of performance, cost, etc., polyethylene and homo- or block-polypropylene are preferable non-polar resins, and polyester resins such as polyethylene terephthalate and polybutylene terephthalate, polyamide resins, ethylene-vinylacetate copolymers, and hydrolysates thereof are preferable polar resins.

When the adhesive film of the present embodiment is configured to include a tacky layer on a predetermined substrate film, the thickness of the tacky layer is preferably <NUM> or more and <NUM> or less and more preferably <NUM> or more and <NUM> or less.

When the thickness of the tacky layer is <NUM> or less, the surface protection film tends to have better handleability, and is economically preferable as well. Moreover, when the thickness is <NUM> or more, there is a tendency that the surface protection film has better adhesion and uniform thickness is likely to be obtained.

The thickness of the substrate film is preferably <NUM> or less, more preferably <NUM> or less, even more preferably <NUM> or less, even more preferably <NUM> or less, and yet more preferably <NUM> or more and <NUM> or less. A film having a thickness of more than <NUM> is generally referred to as a "sheet", and such a sheet is collectively referred to as a film herein.

Examples of the method for producing the adhesive film of the present embodiment include, but are not limited to, a method in which a solution or a melt of the hydrogenated copolymer composition or the adhesive material composition of the present embodiment is applied onto the predetermined substrate film, and a method including coextruding a substrate layer and a tacky layer using a film extruder.

In the case of using the adhesive material composition of the present embodiment, a solution or melt of the composition may be used singly, or a solution or melt of the hydrogenated copolymer composition may be mixed thereto.

Although the method in which a solution the hydrogenated copolymer composition or adhesive material composition of the present embodiment is applied is not limited to the following, the adhesive film can be produced, for example, by dissolving the copolymer composition or composition in a solvent capable of dissolving these, applying the solution to a substrate film with a coater, and thermally drying the solvent.

Although the method in which the hydrogenated copolymer composition or the adhesive material composition of the present embodiment is melted and applied is not limited to the following, the adhesive film can be produced, for example, by applying the molten hydrogenated copolymer composition or adhesive material composition of the present embodiment onto a substrate film with a hot melt coater.

In the case of using this method, a substrate film is preferably used that has a glass transition temperature, melting point, or softening point higher than the coating temperature.

Although the method in which a film extruder is used is not limited to the following, the adhesive film can be produced, for example, in such a manner that the components of the adhesive layer containing the hydrogenated copolymer composition or the adhesive material composition of the present embodiment and the components such as a thermoplastic resin that can constitute the substrate film layer are formed into two streams in a melt coextruder, or that is to say, a fluid for forming the tacky layer and a fluid for forming the substrate film are merged in a dice port and formed into a single fluid and extruded to combine the tacky layer and the resin film layer.

In the case of applying the method in which a film extruder is used, the adhesive material composition of the present embodiment can be produced also by dryblending the components of the hydrogenated copolymer composition and the adhesive material composition in advance. Thus, the method is excellent in productivity. Moreover, when the adhesive film is produced by extrusion molding, the adhesive film tends to have particularly remarkable adhesion and tackiness.

Below, the present embodiment will now be described in detail by way of specific Examples and Comparative Examples, but the present embodiment is not limited to the Examples below.

The methods for measuring and evaluating physical properties applied to the Examples and the Comparative Examples will now be described below.

The peak top molecular weight was measured with GPC [apparatus: manufactured by Waters Corporation].

In the GPC measurement, tetrahydrofuran was used as the solvent, and the temperature was set to <NUM>.

In a chromatograph obtained in the GPC measurement, the peak top molecular weight of each of the peak having the highest peak top (referred to as the "first peak") and the peak having the second highest peak top (referred to as the "second peak") was determined using a calibration curve determined from measurement of commercially available standard polystyrene (prepared using the peak molecular weight of the standard polystyrene). Among the first peak and the second peak, the peak having the smaller peak top molecular weight was regarded as the peak corresponding to the component (a), and the peak having the larger peak top molecular weight was regarded as the peak corresponding to the component (b).

Each of the peaks in the chromatograph obtained in the above GPC measurement was vertically partitioned at an inflection point on the curve between the peaks. The ratio of the area of the first peak and the ratio of the area of the second peak were each determined based on the total area of the peaks. The mass proportions of the component (a) and the component (b) were determined respectively based on the first peak area ratio and the second peak area ratio.

A fitting process based on the Gaussian approximation using EcoSEC waveform separation software was used to partition peaks, and a point of intersection of the peaks was used as the inflection point between the peaks.

A predetermined amount of the hydrogenated copolymer composition was dissolved in chloroform, and the resulting solution was measured with an ultraviolet spectrophotometer (UV-<NUM>, manufactured by Shimadzu Corporation). The content of the vinyl aromatic monomer unit (styrene content) in the hydrogenated copolymer composition was calculated on the basis of the peak strength at the absorption wavelength (<NUM>) attributed to the vinyl aromatic compound (styrene), using the calibration curve.

The block content, vinyl bond content, and degree of hydrogenation in the hydrogenated copolymer composition were measured with nuclear magnetic resonance analysis (NMR) under the following conditions.

In the measurement, the reaction solution after a hydrogenation reaction was introduced to a large amount of methanol to precipitate the hydrogenated copolymer composition for recovery. Next, the hydrogenated copolymer composition was extracted with acetone, the extracted solution was dried in vacuum, and the resultant was used as a sample for <NUM>H-NMR measurement. The conditions for <NUM>H-NMR measurement are as follows.

The MFR [g/<NUM>] of the hydrogenated copolymer composition was measured in compliance with ISO <NUM> under conditions of a temperature of <NUM> and a load of <NUM>.

The hydrogenated copolymer composition was continuously measured using a capillary rheometer (manufactured by Toyo Seiki Seisaku-sho, Ltd. , trade name: CAPILOGRAPH 1D, model: PM-C) under conditions of a temperature of <NUM> and a shear rate of <NUM> sec-<NUM> to <NUM> sec-<NUM>, and the value at <NUM> sec-<NUM> was determined. The value was expressed in Pa·s.

A universal tension and compression tester "Techno Graph TGE-500N: manufactured by Minebea Co. " was used as a measurement apparatus for the tack strength.

An adhesive film prepared as described below and cut to have a width of <NUM> was attached to a PMMA plate (arithmetic mean surface roughness: <NUM>) at a temperature of <NUM> and <NUM>% RH, additionally adhered by rolling a <NUM> rubber roller (a diameter of <NUM>), left to stand for <NUM> minutes, and then peeled off at a rate of <NUM>/min to measure tack strength.

A "<NUM>° peel test" was performed at a temperature of <NUM> and <NUM>% RH to evaluate both initial tackiness and increase in tackiness.

As the initial tackiness, the initial tack strength was measured. For increase in tackiness, the prepared adhesive film was attached in the above-described manner, then heated at <NUM> for <NUM> hour in a gear oven for tack promotion, and left to stand for <NUM> minutes in the measurement environment. Thereafter, the tack strength was measured in accordance with the above-described manner. The initial tackiness and the increase in tackiness were each evaluated in accordance with the following criteria. The "<NUM> peel test" was performed in accordance with the JIS Z0237 standard. The evaluation results of the initial tackiness and increase in tackiness are shown in Tables <NUM> and <NUM> below.

The thickness of the tacky layer was measured to determine the uneven thicknesses during molding. A sample for thickness measurement was cut out from a coextrudate [sample width (TD direction): <NUM>, sample length (MD direction): <NUM>, substrate layer thickness: <NUM>, tacky layer thickness: <NUM>] with a single-edged razor blade. Specifically, at three points, that is, a point at the center of a coextrudate and points at a <NUM>-cm distance from each end of the coextrudate in the TD direction, six portions were cut out at an equal interval in the MD direction to prepare <NUM> samples in total. The cross section in the MD direction of the samples was measured with a microscope "VHX-<NUM>: KEYENCE CORPORATION" to determine the standard deviation of the tacky layer thickness.

Each of the samples of which thickness was measured in the above <Fabricability> evaluation was attached to a PMMA plate (arithmetic mean surface roughness: <NUM>) at a temperature of <NUM> and <NUM>% RH, additionally adhered by rolling a <NUM> rubber roller (a diameter of <NUM>), left to stand for <NUM> minutes, and then peeled off at a rate of <NUM>/min to measure the tack strength. The standard deviation in the tack strength was determined, and then the coefficient of variation was determined.

The hydrogenation catalyst used for the hydrogenation reaction of the hydrogenated copolymer composition was prepared in the following manner.

A nitrogen-purged reaction vessel was charged with <NUM> liter of dried and purified cyclohexane, <NUM> mmol of bis(η5-cyclopentadienyl)titanium dichloride was added, and an n-hexane solution containing <NUM> mmol of trimethylaluminum was added with sufficient stirring, a reaction was performed at room temperature for about <NUM> days to prepare a hydrogenation catalyst.

A1, A2, B1, and B2 described below respectively represent the following polymer blocks.

Batch polymerization was performed in the following manner with a stirred jacketed tank reactor (internal volume: <NUM>).

The reactor was charged with a cyclohexane solution containing <NUM> of cyclohexane and <NUM> parts by mass of a butadiene monomer (butadiene monomer concentration: <NUM> mass%), and <NUM> mol of N,N,N',N'-tetramethylethylenediamine (hereinafter, also referred to as "TMEDA") was added thereto per <NUM> mol of the following n-butyl lithium (hereinafter, also referred to as "Bu-Li"). Then, after the temperature was adjusted to <NUM>, <NUM> parts by mass of Bu-Li were added per <NUM> parts by mass of the total amount of the butadiene monomer and the styrene monomer introduced into the reactor in the present Production Example (hereinafter referred to as all the monomers), and the reaction was continued for <NUM> minutes while the temperature inside the reactor was adjusted to <NUM>.

<NUM> parts by mass of a styrene monomer were introduced thereto, and thereafter, the reaction was further continued for <NUM> minutes while the temperature inside the reactor was adjusted to <NUM>.

A cyclohexane solution containing <NUM> parts by mass of a butadiene monomer (butadiene monomer concentration: <NUM> mass%) was introduced thereto, and thereafter, the reaction was further continued for <NUM> minutes while the temperature inside the reactor was adjusted to <NUM> to obtain a butadiene - styrene - butadiene copolymer.

As a coupling agent, <NUM> mol of tetraethoxysilane was added thereto per <NUM> mol of Bu-Li to crosslink a portion of the butadiene - styrene - butadiene copolymer, and as a reaction terminator, <NUM> mol of ethanol was added per <NUM> mol of Bu-Li to obtain a mixture of the butadiene - styrene - butadiene copolymer and a crosslinked product thereof (copolymer composition).

The hydrogenation catalyst prepared as described above was used to continuously hydrogenate the obtained copolymer composition at <NUM> to obtain a hydrogenated copolymer composition. The amount of the catalyst was <NUM> ppm, and the hydrogen pressure in the hydrogenation polymerization reactor was <NUM> MPa. After the reaction was completed, <NUM> parts by mass of a stabilizer (octadecyl-<NUM>-(<NUM>,<NUM>-di-t-butyl-<NUM>-hydroxyphenyl)propionate) were added based on <NUM> parts by mass of the hydrogenated copolymer composition.

A hydrogenated copolymer composition was obtained in the same manner as in Production Example <NUM> except that the amount of Bu-Li added in the first step was changed to <NUM> parts by mass.

A hydrogenated copolymer composition was obtained in the same manner as in Production Example <NUM> except that the amount of Bu-Li added in the first step was changed to <NUM> parts by mass, the amount of the styrene monomer introduced in the second step was changed to <NUM> parts by mass, and the amount of the butadiene monomer introduced in the third step was changed to <NUM> parts by mass.

A hydrogenated copolymer composition was obtained in the same manner as in Production Example <NUM> except that the amount of Bu-Li added in the first step was changed to <NUM> parts by mass, the additive in the fourth step was replaced by ethyl benzoate, and the amount of ethyl benzoate was <NUM> mol per <NUM> mol of Bu-Li.

A hydrogenated copolymer composition was obtained in the same manner as in Production Example <NUM> except that the amount of tetraethoxysilane added in the fourth step was changed to <NUM> mol per <NUM> mol of Bu-Li.

A hydrogenated copolymer composition was obtained in the same manner as in Production Example <NUM> except that the reaction time in the first step was changed to <NUM> minutes.

A hydrogenated copolymer composition was obtained in the same manner as in Production Example <NUM> except that the amount of the butadiene monomer for charging in the first step was changed to <NUM> parts by mass and the amount of the butadiene monomer introduced in the third step was changed to <NUM> parts by mass.

A hydrogenated copolymer composition was obtained in the same manner as in Production Example <NUM> except that the amount of Bu-Li added in the first step was changed to <NUM> parts by mass and the amount of TMEDA added was changed to <NUM> mol per <NUM> mol of Bu-Li.

A hydrogenated copolymer composition was obtained in the same manner as in Production Example <NUM> except that the amount of Bu-Li added in the first step was changed to <NUM> parts by mass, the amount of TMEDA added per <NUM> mol of Bu-Li was changed to <NUM> mol, and the temperature inside the reactor in the third step was changed to <NUM>.

A hydrogenated copolymer composition was obtained in the same manner as in Production Example <NUM> except that the amount of the hydrogenation catalyst in the fifth step was changed to <NUM> ppm.

A hydrogenated copolymer composition was obtained in the same manner as in Production Example <NUM> except that the additive in the fourth step was replaced by silicon tetrachloride and the amount of silicon tetrachloride was <NUM> mol per <NUM> mol of Bu-Li.

The reactor was charged with <NUM> of cyclohexane and <NUM> parts by mass of a styrene monomer, and <NUM> mol of TMEDA was added thereto per <NUM> mol of the following Bu-Li. Then, after the temperature was adjusted to <NUM>, <NUM> parts by mass of Bu-Li were added per <NUM> parts by mass of the total amount of the butadiene monomer and the styrene monomer introduced into the reactor in the present Production Example (hereinafter referred to as all the monomers), and the reaction was continued for <NUM> minutes while the temperature inside the reactor was adjusted to <NUM>.

A cyclohexane solution containing <NUM> parts by mass of a butadiene monomer (butadiene monomer concentration: <NUM> mass%) was introduced thereto, and thereafter, the reaction was further continued for <NUM> minutes while the temperature inside the reactor was adjusted to <NUM> to obtain a styrene - butadiene copolymer.

As a reaction terminator, <NUM> mol of ethanol was added per <NUM> mol of Bu-Li. Thereafter, <NUM> mol of tetraethoxysilane as a coupling agent was added per <NUM> mol of Bu-Li to crosslink a portion of the styrene-butadiene copolymer, and thus, a mixture of the styrene-butadiene copolymer and a crosslinked product thereof (copolymer composition) was obtained.

A hydrogenated copolymer composition was obtained in the same manner as in Production Example <NUM> except that the amount of the styrene monomer for charging in the first step was changed to <NUM> parts by mass and the amount of the butadiene monomer introduced in the second step was changed to <NUM> parts by mass.

A hydrogenated copolymer composition was obtained in the same manner as in Production Example <NUM> except that the amount of TMEDA in the first step was changed to <NUM> mol per <NUM> mol of Bu-Li and the temperature inside the reactor in the second step was changed to <NUM>.

The reactor was charged with a cyclohexane solution containing <NUM> of cyclohexane and <NUM> parts by mass of a butadiene monomer (butadiene monomer concentration: <NUM> mass%), and <NUM> mol of TMEDA was added thereto per <NUM> mol of the following Bu-Li. Then, after the temperature was adjusted to <NUM>, <NUM> parts by mass of Bu-Li were added per <NUM> parts by mass of the total amount of the butadiene monomer and the styrene monomer introduced into the reactor in the present Production Example (hereinafter referred to as all the monomers), and the reaction was continued for <NUM> minutes while the temperature inside the reactor was adjusted to <NUM>.

Thereto, <NUM> parts by mass of a styrene monomer were introduced, and thereafter, the reaction was further continued for <NUM> minutes while the temperature inside the reactor was adjusted to <NUM>.

A cyclohexane solution containing <NUM> parts by mass of a butadiene monomer (butadiene monomer concentration: <NUM> mass%) was introduced thereto, and thereafter, the reaction was further continued for <NUM> minutes while the temperature inside the reactor was adjusted to <NUM>.

After <NUM> parts by mass of a styrene monomer was introduced and the reaction was carried out for <NUM> minutes while the temperature was adjusted to <NUM>, <NUM> mol of ethanol as a reaction terminator was added per <NUM> mol of Bu-Li to thereby obtain a butadiene - styrene-butadiene - styrene copolymer.

The hydrogenation catalyst prepared as described above was used to continuously hydrogenate the obtained copolymer at <NUM> to obtain a hydrogenated copolymer. The amount of the catalyst was <NUM> ppm, and the hydrogen pressure in the hydrogenation polymerization reactor was <NUM> MPa. After the reaction was completed, <NUM> parts by mass of a stabilizer (octadecyl-<NUM>-(<NUM>,<NUM>-di-t-butyl-<NUM>-hydroxyphenyl) propionate) was added based on <NUM> parts by mass of the hydrogenated copolymer.

A hydrogenated copolymer was obtained in the same manner as in Production Example <NUM> except that the amount of Bu-Li added in the first step was changed to <NUM> parts by mass, the amount of TMEDA added was changed to <NUM> mol per <NUM> mol of Bu-Li, the amount of the styrene monomer introduced in the second step was changed to <NUM> parts by mass, the temperature inside the reactor in the third step was changed to <NUM>, the amount of the styrene monomer introduced in the fourth step was changed to <NUM> parts by mass, and the amount of the butadiene monomer introduced in the third step was changed to <NUM> parts by mass.

A hydrogenated copolymer was obtained in the same manner as in Production Example <NUM> except that the amount of Bu-Li added in the first step was changed to <NUM> parts by mass.

A hydrogenated copolymer composition was obtained in the same manner as in Production Example <NUM> except that the amount of TMEDA added in the first step was changed to <NUM> mol per <NUM> mol of Bu-Li, the amount of Bu-Li added was changed to <NUM> parts by mass, the amount of styrene monomer for charging was changed to <NUM> parts by mass, the amount of the butadiene monomer introduced in the second step was changed to <NUM> parts by mass, the temperature inside the reactor was changed to <NUM>, no ethanol was added in the third step, the coupling agent was replaced by methyldichlorosilane, and the amount of methyldichlorosilane added was changed to <NUM> mol per <NUM> mol of Bu-Li.

A hydrogenated copolymer composition was obtained in the same manner as in Production Example <NUM> except that the amount of TMEDA added in the first step was changed to <NUM> mol per <NUM> mol of Bu-Li, the amount of Bu-Li added was changed to <NUM> parts by mass, the amount of the styrene monomer for charging was changed to <NUM> parts by mass, the amount of the butadiene monomer introduced in the second step was changed to <NUM> parts by mass, no ethanol was added in the third step, the coupling agent was replaced by methyldichlorosilane, and the amount of methyldichlorosilane added was changed to <NUM> mol per <NUM> mol of Bu-Li.

A hydrogenated copolymer composition was obtained in the same manner as in Production Example <NUM> except that the amount of TMEDA added in the first step was changed to <NUM> mol per <NUM> mol of Bu-Li, the amount of Bu-Li added was changed to <NUM> parts by mass, the amount of the styrene monomer introduced was changed to <NUM> parts by mass, the amount of the butadiene monomer introduced in the second step was changed to <NUM> parts by mass, no ethanol was added in the third step, the coupling agent was replaced by Epotohto ZX-<NUM> (Nippon Steel & Sumikin Chemical Co. ), and the amount of Epotohto ZX-<NUM> added was changed to <NUM> mol per <NUM> mol of Bu-Li.

A hydrogenated copolymer composition was obtained in the same manner as in Production Example <NUM> except that the amount of TMEDA added in the first step was changed to <NUM> mol per <NUM> mol of Bu-Li and the temperature inside the reactor in the third step was changed to <NUM>.

A hydrogenated copolymer composition was obtained in the same manner as in Production Example <NUM> except that the amount of TMEDA added in the first step was changed to <NUM> mol per <NUM> mol of Bu-Li.

The structures of the component (a) and the component (b) included in the hydrogenated copolymer compositions obtained in Production Examples <NUM> to <NUM> and <NUM> to <NUM> are each shown in Table <NUM>. The physical properties of these hydrogenated copolymer compositions are also shown in Table <NUM>.

The hydrogenated copolymer composition to constitute the tacky layer, and a tackifier (manufactured by Yasuhara Chemical Co. , trade name "YS Polystar G150") (<NUM> parts by mass based on <NUM> parts by mass of the hydrogenated copolymer composition) were homogeneously mixed. The mixture to constitute the tacky layer and polypropylene (manufactured by SunAllomer Ltd. , trade name "PC684S", MFR (<NUM>, load: <NUM>) = <NUM>/<NUM>) to constitute the substrate layer were coextruded by a T-die coextrusion method such that both the layers were integrated to thereby produce an adhesive film having a substrate layer thickness of <NUM> and a tacky layer thickness of <NUM>.

The adhesive film comprising the tacky layer including the hydrogenated copolymer composition obtained of each of Production Examples <NUM> to <NUM> and <NUM> to <NUM> was used to evaluate the initial tackiness and the increase in tackiness. The evaluation results are shown in the following Table <NUM>.

As shown in Table <NUM>, Examples <NUM> to <NUM> and <NUM> to <NUM> exhibited excellent performance in the initial tackiness and increase in tackiness. When the fabricability was good and the tacky layer had few uneven thicknesses, the tack strength had few variations as well, and the result of coefficient of variation of the initial tack strength was also good. On the other hand, in Comparative Examples <NUM> to <NUM>, the initial tackiness, increase in tackiness, and fabricability were not practically evaluated as good.

The structures of the component (a) and the component (b) included in the hydrogenated copolymer compositions obtained in Production Examples <NUM> to <NUM>, <NUM> to <NUM>, and <NUM> to <NUM> and the structure of the hydrogenated copolymers obtained in Production Examples <NUM> to <NUM> are shown in Table <NUM>. The physical properties of these hydrogenated copolymer compositions and hydrogenated copolymers are also shown in Table <NUM>.

The hydrogenated copolymer composition or hydrogenated copolymer to constitute the tacky layer, and a tackifier (manufactured by Yasuhara Chemical Co. , trade name "YS Resin PX1150N") (<NUM> parts by mass based on <NUM> parts by mass of the hydrogenated copolymer composition) were homogeneously mixed. The mixture to constitute the tacky layer and polypropylene (manufactured by SunAllomer Ltd. , trade name "PC684S", MFR (<NUM>, load: <NUM>) = <NUM>/<NUM>) to constitute the substrate layer were coextruded by a T-die coextrusion method such that both the layers were integrated to thereby produce an adhesive film having a breadth of <NUM>, a substrate layer thickness of <NUM>, and a tacky layer thickness of <NUM>.

The adhesive films comprising the tacky layer including the hydrogenated copolymer composition or hydrogenated copolymer obtained in each of Production Examples <NUM> to <NUM> and <NUM> to <NUM> were used to evaluate the initial tackiness, the increase in tackiness, and the fabricability. The evaluation results are shown in the following Table <NUM>.

As shown in Table <NUM>, Examples <NUM> to <NUM> exhibited excellent performance in the initial tackiness, increase in tackiness, and fabricability. When the fabricability was good, the tack strength had few variations as well, and the result of coefficient of variation of the initial tack strength was also good.

On the other hand, in Comparative Examples <NUM> to <NUM>, the initial tackiness, increase in tackiness, and fabricability were not practically evaluated as good. As described above, in the hydrogenated copolymer compositions having a specific structure, particularly when the relationship between the capillary viscosity and the MFR falls within a specific range, the balance between the fabricability and the tackiness performance was confirmed to be highly achieved.

Claim 1:
An adhesive material composition comprising a hydrogenated copolymer composition and a tackifier, the hydrogenated copolymer composition comprising:
a component (a) comprising a polymer block comprising a vinyl aromatic monomer unit as a main component and a polymer block comprising a conjugated diene monomer unit as a main component; and
a component (b) comprising a polymer block comprising a vinyl aromatic monomer unit as a main component and a polymer block comprising a conjugated diene monomer unit as a main component, wherein
the component (a) has a peak top molecular weight of <NUM>,<NUM> to <NUM>,<NUM>,
the component (b) has a peak top molecular weight <NUM> times to <NUM> times the peak top molecular weight of the component (a),
<NUM> mol% or more of double bonds of the conjugated diene monomer unit included in the hydrogenated copolymer composition is hydrogenated,
the content of the vinyl aromatic monomer unit included in the hydrogenated copolymer composition is <NUM> to <NUM> mass% based on the composition,
the block content of the vinyl aromatic monomer unit included in the hydrogenated copolymer composition is <NUM> mass% or more,
the melt flow rate (MFR) of the hydrogenated copolymer composition is <NUM> to <NUM>/<NUM>,
the capillary viscosity of the hydrogenated copolymer composition is <NUM> to <NUM> Pa·s, and
when the capillary viscosity is denoted by C [Pa·s] and the MFR is denoted by M [g/<NUM>], a relationship of (Expression <NUM>): <MAT> is satisfied;
wherein the peak top molecular weight is determined by obtaining a molecular weight corresponding to the top of the peak obtained by gel permeation chromatography (GPC) (solvent: tetrahydrofuran, temperature: <NUM>) from a standard polystyrene calibration curve;
wherein the melt flow rate of the hydrogenated copolymer composition is measured in compliance with ISO <NUM> under conditions of a temperature of <NUM> and a load of <NUM>; and
wherein the capillary viscosity is a value obtained by measurement in compliance with ISO <NUM>, but has not been subjected to the Bagley correction or the Rabinovitch correction, under the measurement apparatus conditions below, wherein the accuracy of the numerical values below and conditions not specified below are compliant to ISO <NUM>:
Capillary die inner diameter: φ1.<NUM>
Capillary die length: <NUM>
Inlet angle: <NUM>°
Piston diameter: φ9.<NUM>
Furnace body diameter: φ9.<NUM>.