JP2008274211A - Pressure-sensitive adhesive composition and surface-protecting film - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a pressure-sensitive adhesive composition capable of suppressing a rise in pressure-sensitive adhesive force of a surface-protecting film and the like. <P>SOLUTION: The pressure-sensitive adhesive composition is obtained by hydrogenating a block copolymer comprising a polymer block a, mainly composed of an aromatic vinyl compound unit, and a polymer block b, comprised of 55-99 mass% of a conjugated diene compound unit and 45-1 mass% of an aromatic vinyl compound unit and having a vinyl bond content of at least 60%, and having a structure of [a-b]<SB>x</SB>-Y (wherein a is the polymer block a; b is the polymer block b; x is an integer of at least 2; and Y is a residue of a coupling agent) with a mass ratio, a/b, of the polymer block a to the polymer block b of 5/95 to 45/55, and has a weight-average molecular weight of 50,000-500,000, a hydrogenation rate of at least 80%, a melt flow rate of 5-100 g/10 min as measured at 230°C under a load of 21.2 N, and a rise in peel strength (after kept in a 40°C atmosphere for 7 days) of at most 0.55 N/10 mm. <P>COPYRIGHT: (C)2009,JPO&INPIT

Description

  The present invention relates to a pressure-sensitive adhesive composition and a surface protective film formed by forming a pressure-sensitive adhesive layer using the pressure-sensitive adhesive composition.

  Conventionally, in order to protect the surface of various members such as metal plates, coated coated steel plates, synthetic resin plates, decorative plywood, nameplates, and glass plates from contamination and damage, the surfaces of these members are covered with a surface protective film. Things have been done.

  Generally, the surface protective film has a configuration including a film-like base material layer and an adhesive layer formed on the surface of the base material layer. Such a surface protective film can protect the surface of a to-be-protected body from contamination and damage by sticking a film-form base material on the surface of a to-be-protected body through an adhesive layer.

Examples of the pressure-sensitive adhesive composition for forming the pressure-sensitive adhesive layer of the surface protective film include a polymer block A having an aromatic alkenyl compound unit as a main repeating unit and a hydrogenated conjugated diene compound unit as a main repeating unit. It has been proposed to use an adhesive composition comprising a block copolymer containing the polymer block B as a constituent component. More specifically, a pressure-sensitive adhesive composition for a surface protective film containing a [A-B] type block copolymer or a [ABA] type block copolymer (provided that “A” Polymer block A, “B” indicates polymer block B) (see, for example, Patent Documents 1 and 2).
Japanese Patent Publication No. 6-23365 Japanese Patent No. 2713519

However, the pressure-sensitive adhesive compositions described in Patent Documents 1 and 2 are stored in a state where they are stacked or wound in a coil shape after being bonded to an object to be protected (adhered body) such as a metal plate. For this reason, the adhesive force has been developed over time, and as a result, when the surface protective film is peeled off from the surface of the adherend, the peeling operation is difficult, or the surface protective film or the adhesive is placed on the adherend. Problems such as partial remaining of adhesive (residue residue) may occur. Even when the pressure-sensitive adhesive composition is used as an adhesive between an uneven film such as an optical film (for example, a prism sheet, a diffusion plate, etc.) and a surface protective film, After peeling off the protective film, there may be a problem that the function of the optical film is deteriorated due to the residual adhesive composition due to the increase in the adhesive strength of the adhesive composition.
The present invention is intended to solve the above-mentioned problems of the prior art, and provides a pressure-sensitive adhesive composition having a small degree of progress of pressure-sensitive adhesive over time, and a surface protective film produced using the composition. For the purpose.

  As a result of intensive studies to solve the above-mentioned problems of the prior art, the present inventors have identified the structure of the block copolymer constituting the pressure-sensitive adhesive composition, the composition of monomer units, physical properties, etc. As a result, the present invention has been completed. Specifically, the following pressure-sensitive adhesive composition and the like are provided by the present invention.

The present invention provides the following [1] to [8].
[1] A pressure-sensitive adhesive composition comprising the following component (a), wherein an increase in peel strength (left in a 40 ° C. atmosphere for 7 days) is 0.55 N / 10 mm or less object.
[Component (a)] The following polymer block a and the following polymer block b are included, and [ab] _x -Y (where a is the polymer block a, b is the polymer block b, and x is 2 or more. And Y represents a coupling agent residue.), Wherein the mass ratio of the polymer block a to the polymer block b is a / b = 5/95 to 45 Hydrogenated copolymer satisfying the following conditions (1) to (3) obtained by hydrogenating a / 55 block copolymer [polymer block a] a polymer block mainly composed of aromatic vinyl compound units [ Polymer block b] A polymer block containing 55 to 99% by mass of a conjugated diene compound unit and 45 to 1% by mass of an aromatic vinyl compound unit, wherein the vinyl bond content in the conjugated diene compound unit is 60% or more ( 1) The weight average molecular weight is 5-5 It is a man.
(2) The hydrogenation rate is 80% or more.
(3) The melt flow rate measured by 230 degreeC and a 21.2N load is 5-100 g / 10min.
[2] The pressure-sensitive adhesive according to [1], comprising the following component (b), wherein the blending amount of component (b) is 50% by mass or more in a total of 100% by mass of component (b) and component (b) Composition.
[(B) component] The following polymer block a and the following polymer block b are included, and [ab] _n (where a is a polymer block a, b is a polymer block b, and n is an integer of 1 to 3). Hydrogenated copolymer obtained by hydrogenating a block copolymer having the structure of [Polymer block a] Polymer block mainly composed of an aromatic vinyl compound unit [Polymer block b] Conjugated diene compound Polymer block [3] containing the unit 55-99 mass% and the aromatic vinyl compound unit 45-1 mass%, and the vinyl bond content rate in this conjugated diene compound unit is 60% or more And the mass ratio of the total blending amount of the component (a) and the component (b) and the blending amount of the component (c) is ((b) + (b)) / (c) = 10 The pressure-sensitive adhesive composition according to the above [2], which is 90 / 90-10.
[Component (c)] A block copolymer comprising the following polymer block a, the following polymer block c, and the following polymer block d, wherein the mass ratio of the aromatic vinyl compound unit / conjugated diene compound unit is Hydrogenated copolymer satisfying the following condition (1) obtained by hydrogenating a block copolymer of 5/95 to 60/40 [polymer block a] a polymer block mainly composed of aromatic vinyl compound units [Polymer block c] A polymer block consisting only of a conjugated diene compound unit or a random copolymer block of a conjugated diene compound unit and an aromatic vinyl compound unit (however, the content of the aromatic vinyl compound unit is 45% by mass) The polymer block [polymer block d] conjugated die in which the content of vinyl bonds in the conjugated diene compound unit is 60% or more. And a compound units and aromatic vinyl compound unit, tapered block (1) the hydrogenation ratio of the aromatic vinyl compound unit gradually increases is 80% or more.
[4] The following (d) component is included, and the mass ratio of the combined amount of the component (b) and the component (b) and the amount of the component (d) is ((b) + (b) )) / (D) = 10 / 90-90 / 10, The pressure-sensitive adhesive composition according to the above [2].
[(D) Component] The following polymer block e and the following polymer block f are included, and e- (fe) _n or (ef) _m (where e is the polymer block e, f is Polymer blocks f, n and m each independently represent an integer of 1 or more), wherein the mass ratio of polymer block e to polymer block f is e / f = Hydrogenated copolymer obtained by hydrogenating a block copolymer of 5/95 to 50/50 satisfying the following condition (1) [polymer block e] polybutadiene having a vinyl bond content of 30% or less Block [polymer block f] A polymer block containing a conjugated diene compound unit, wherein the vinyl bond content in the conjugated diene compound unit is 60% or more (1) The hydrogenation rate is 80% or more.
[5] The following (e) component is included, and the mass ratio between the total amount of the component (a) and the component (b) and the amount of the component (e) is ((b) + (b) )) / (E) = The pressure-sensitive adhesive composition according to the above [2], which is 10/90 to 90/10.
[Component (e)] A block copolymer comprising the following polymer block a, the following polymer block g and the following polymer block e, wherein the polymer block a, the polymer block b and the polymer block e In the total 100% by mass, the content of the polymer block a is 5 to 40% by mass, the content of the polymer block g is 30 to 90% by mass, and the content of the polymer block e is 5 to 40% by mass. Hydrogenated copolymer satisfying the following condition (1) obtained by hydrogenating the block copolymer [polymer block a] polymer block mainly composed of aromatic vinyl compound units [polymer block g] conjugated diene compound A polymer block [polymer block e] containing 55 to 100% by mass of units and 45 to 0% by mass of aromatic vinyl compound units, and having a vinyl bond content in the conjugated diene compound unit of 40% or more. Polybutadiene block (1) the hydrogenation ratio content of alkenyl bond is 30% or less is 80% or more.
[6] The following (F) component is included, and the mass ratio of the total blending amount of the (B) component and the (B) component and the blending amount of the (F) component is ((A) + (B) )) / (F) = 10/90 to 90/10, The pressure-sensitive adhesive composition according to the above [2].
[(F) Component] A block copolymer comprising the following polymer block a and the following polymer block b, wherein the mass ratio of the polymer block a to the polymer block b is a / b = 5/95. The following condition (1) is obtained by hydrogenating a block copolymer having a molecular block of 45/55 and at least two terminals being a polymer block a and having at least one polymer block b at an intermediate portion. Filled hydrogenated copolymer.
[Polymer block a] A polymer block mainly composed of an aromatic vinyl compound unit [Polymer block b] containing 55 to 100% by mass of a conjugated diene compound unit and 45 to 0% by mass of an aromatic vinyl compound unit. Polymer block having a vinyl bond content of 60% or more in the diene compound unit (1) The hydrogenation rate is 80% or more.
[7] A surface protective film comprising a base material layer made of polyolefin and a pressure-sensitive adhesive layer formed on one side of the base material layer, wherein the pressure-sensitive adhesive layer is the above [1] to [6] ] The surface protection film which consists of an adhesive composition in any one of.
[8] A method for producing a surface protective film according to [7], comprising a step of laminating the base material layer and the pressure-sensitive adhesive layer by extrusion molding.

The pressure-sensitive adhesive composition of the present invention is adhered to an adherend (for example, an optical film) when used as a material for a pressure-sensitive adhesive layer in a pressure-sensitive adhesive layer-containing member (for example, an optical surface protective film). After that, the degree of progress of the adhesive strength over time is small. Therefore, when the adhesive layer containing member (optical surface protective film, etc.) is peeled from the adherend, there is no problem such as adhesive residue. The peeling operation can be performed easily and quickly.
The pressure-sensitive adhesive layer-containing member having a pressure-sensitive adhesive layer made of the pressure-sensitive adhesive composition of the present invention is optimal for use as an optical surface protective film (for example, a surface protective film for an optical film).

  The best mode for carrying out the present invention will be specifically described below. However, the present invention includes all embodiments as long as it includes the specific matters defined in the claims, and is not limited to the embodiments described below.

[1] Adhesive composition The adhesive composition of the present invention comprises one or more types of copolymers (hereinafter referred to as copolymer compositions) and other optional components added as necessary. Is included.
The copolymer composition needs to contain the following component (a), and preferably contains the component (a) and the component (b) below. Furthermore, the copolymer composition contains at least one selected from the following (c) component, (d) component, (e) component, and (f) component in addition to the (a) component and the (b) component. be able to.
Hereinafter, each of the components (a) to (f) will be described. In the present specification, the “repeating unit derived from the monomer X” may be simply referred to as “X unit”.

[(I) component]
The component (a) includes the following polymer block a and the following polymer block b, and [ab] _x -Y (where a is the polymer block a, b is the polymer block b, and x is 2 or more. And Y represents a coupling agent residue.) A hydrogenated copolymer obtained by hydrogenating a block copolymer having a structure of (a copolymer before hydrogenation).
[Polymer block a] A polymer block mainly composed of an aromatic vinyl compound unit [Polymer block b] containing 55 to 99% by mass of a conjugated diene compound unit and 45 to 1% by mass of an aromatic vinyl compound unit. Polymer block in which the content of vinyl bonds in the diene compound unit is 60% or more (a) The polymer block a constituting the pre-hydrogenation copolymer of the component is a polymer block mainly composed of an aromatic vinyl compound unit. It is. The content of the aromatic vinyl compound unit in the polymerization block a is preferably 50% by mass or more, more preferably 60% by mass or more, further preferably 70% by mass or more, and most preferably 80% by mass or more. When the content is increased, there is an advantage that the thermoplasticity of the pressure-sensitive adhesive composition can be improved and recycling of the pressure-sensitive adhesive composition becomes easier.
Among the repeating units (monomer units) constituting the polymer block a, the repeating unit other than the aromatic vinyl compound unit is a repeating unit derived from a compound copolymerizable with the aromatic vinyl compound, such as a conjugated diene. The repeating unit derived from a compound, a (meth) acrylic acid ester compound, etc. can be mentioned. Among these, 1,3-butadiene and isoprene are preferable because they have high copolymerizability with an aromatic vinyl compound.
Examples of the aromatic vinyl compound which is a monomer constituting the aromatic vinyl compound unit include styrene, tert-butylstyrene, α-methylstyrene, p-methylstyrene, p-ethylstyrene, divinylbenzene, 1, Examples thereof include 1-diphenylethylene, vinylnaphthalene, vinylanthracene, N, N-diethyl-p-aminoethylstyrene and vinylpyridine. Of these, styrene is preferred because the raw materials are easily industrially available.

(A) The polymer block b constituting the pre-hydrogenation copolymer of the component contains 55 to 99% by mass of a conjugated diene compound unit and 45 to 1% by mass of an aromatic vinyl compound unit. The polymer block has a vinyl bond content of 60% or more.
In the polymer block b, the content of the conjugated diene compound unit is 55 to 99% by mass, preferably 60 to 99% by mass, more preferably 65 to 99% by mass, and most preferably 70 to 99% by mass.
In the polymer block b, the content of the aromatic vinyl compound unit is 1 to 45% by mass, preferably 1 to 40% by mass, more preferably 1 to 35% by mass, and most preferably 1 to 30% by mass.
By making the content rate of a conjugated diene compound unit and an aromatic vinyl compound unit into said numerical range, the softness | flexibility of an adhesive composition can be improved.
In addition, the other monomer (for example, (meth) acrylic acid ester compound etc.) which comprises repeating units other than a conjugated diene compound unit and an aromatic vinyl compound unit can also be used. The content of other monomers in the polymer block b is preferably 10% by mass or less, more preferably 5% by mass or less.
Examples of the aromatic vinyl compound monomer constituting the aromatic vinyl compound unit include those described above, and styrene is preferred. Examples of the conjugated diene compound monomer constituting the conjugated diene compound unit include 1,3-butadiene, isoprene, 2,3-dimethyl-1,3-butadiene, 1,3-pentadiene, and 2-methyl-1. , 3-octadiene, 1,3-hexadiene, 1,3-cyclohexadiene, 4,5-diethyl-1,3-octadiene, 3-butyl-1,3-octadiene, myrcene, chloroprene and the like. Of these, 1,3-butadiene and isoprene are preferred because of high polymerization reactivity and easy availability of raw materials industrially.
In the polymer block b, the content of vinyl bonds (that is, the total mass ratio of 1,2-vinyl bonds and 3,4-vinyl bonds; hereinafter, also referred to as “vinyl bond content”) is 60% or more. Preferably it is 60 to 90%, more preferably 60 to 85%. By setting the vinyl bond content within the above range, a pressure-sensitive adhesive composition having an excellent balance between tack and adhesive strength can be obtained.
In the copolymer before hydrogenation, the mass ratio of the polymer block a to the polymer block b is a / b = 5/95 to 45/55, preferably 5/95 to 30/70. More preferably, it is 5 / 95-20 / 80.

A hydrogenated copolymer obtained by hydrogenating such a pre-hydrogenated copolymer (component (A)) is [AB] _x -Y (where A is a polymer derived from the polymer block a). And B represents a polymer block derived from the polymer block b, x represents an integer of 2 or more, and Y represents a coupling agent residue.
Examples of the hydrogenated copolymer having the above structure include a bimolecular coupling body represented by [(AB) -Y- (BA)] (when x = 2), 3 Examples thereof include coupling bodies having more than molecules (so-called star polymers). However, the production of component (a) by coupling too many polymers is accompanied by side reactions, which may make it difficult to control the physical properties of the polymer. Therefore, x is preferably an integer of 2 to 4.
The component (a) can be synthesized in one pot with the component (b) described later using a coupling method. The details of the coupling method and the like will be described in detail in the section of the manufacturing method.

The hydrogenation rate of the hydrogenated copolymer is 80% or more, preferably 90% or more, more preferably 95% or more. When the hydrogenation rate is 80% or more, a pressure-sensitive adhesive composition having excellent heat resistance can be obtained. In the present specification, the “hydrogenation rate” means a hydrogenation rate calculated from a 270 MHz, ¹ H-NMR spectrum using carbon tetrachloride as a solvent.
The weight average molecular weight of the hydrogenated copolymer is preferably 50,000 to 500,000, more preferably 50,000 to 300,000. By making the weight average molecular weight within the range of 50,000 to 500,000, industrial production of the copolymer composition containing the component (a) can be facilitated. When the weight average molecular weight is less than 50,000, the polymer adheres to the production equipment or the like in the step of removing the solvent and drying the polymer, and industrial production of the component (a) may be difficult. On the other hand, when the weight average molecular weight exceeds 500,000, the solubility in a solvent and the heat melting property are deteriorated, and the formation of the pressure-sensitive adhesive layer may be difficult. In the present specification, “weight average molecular weight” means a weight average molecular weight in terms of polystyrene measured by gel permeation chromatography (GPC).
The hydrogenated copolymer has a melt flow rate measured at 230 ° C. and a load of 21.2 N of 5 to 100 g / 10 minutes, preferably 5 to 50 g / 10 minutes, more preferably 5 to 20 g / 10 minutes. is there.

[(B) component]
The component (b) includes a polymer block a and a polymer block b (wherein the polymer blocks a and b are defined in the same manner as the polymer blocks a and b in the component (a)), [A-b] _n (where a is a polymer block a, b is a polymer block b, and n is an integer of 1 to 3). A hydrogenated copolymer obtained by hydrogenating the compound).
The conditions such as the content of the aromatic vinyl compound unit, the vinyl bond content, and the type of monomer used in the polymer block a and the polymer block b constituting the pre-hydrogenated copolymer are as described above (ii). ) The same as in the component.
The hydrogenated copolymer used as the component (b) is [AB] _n (where A is a polymer block derived from the polymer block a, B is a polymer block derived from the polymer block b, n Represents an integer of 1 to 3.).
Examples of such a hydrogenated copolymer include [AB] (n = 1), [ABABB] (n = 2), and [ABABABA]. B] (n = 3) and the like. In these block copolymers, each of the polymer blocks A and B may be a different polymer block, for example, [A ₁ -B ₁ -A ₂ -B ₂ ], or , [A ₁ -B ₁ -A ₁ -B ₁ ] may be the same polymer block. When n is an integer of 1 to 3, industrial productivity is good. On the other hand, when n is 4 or more, industrial productivity is lowered, which is not preferable. In addition, from the viewpoint of improving adhesive strength and material strength, n is more preferably 1 to 2, and particularly preferably 1. That is, as the hydrogenated copolymer used as the component (b), a block copolymer having a structure of [AB] is particularly preferable from the viewpoint of improving adhesive strength.
Moreover, in the structure of [AB] _n , it is preferable that the terminal polymer block B occupies 2 mass% or more of the whole copolymer. This is because the effect of the polymer block B is surely exhibited.

The molecular weight of the hydrogenated copolymer is not particularly limited, but the weight average molecular weight is preferably 30,000 to 500,000, more preferably 80,000 to 300,000, and 80,000 to 200,000. It is particularly preferred. By making the weight average molecular weight within the range of 30,000 to 500,000, it is possible to facilitate industrial production of a copolymer composition (for example, one comprising the component (A) and the component (B)). Can do. When the weight average molecular weight is less than 30,000, the polymer adheres to the production equipment or the like in the step of removing the solvent and drying the polymer, and industrial production of the component (b) may be difficult. On the other hand, when the weight average molecular weight exceeds 500,000, the solubility in a solvent and the heat melting property are deteriorated, and the formation of the pressure-sensitive adhesive layer may be difficult.
The melt flow rate of the hydrogenated copolymer measured at 230 ° C. and 21.2 N load is preferably 0.01 to 100 g / 10 minutes, more preferably 0.01 to 80 g / 10 minutes.

[(C) component]
The component (c) comprises the following polymer block a (wherein the definition and details of the polymer block a are the same as those of the polymer block a in the above-mentioned component (a)), and the following polymer block c. A block copolymer (copolymer before hydrogenation) comprising the following polymer block d, wherein the mass ratio of the aromatic vinyl compound unit / conjugated diene compound unit is 5/95 to 60/40. A hydrogenated copolymer obtained by hydrogenating a polymer so that the hydrogenation rate is 80% or more.
[Polymer block a] Polymer block mainly composed of aromatic vinyl compound units [Polymer block c] A polymer block consisting only of conjugated diene compound units, or a random copolymer of conjugated diene compound units and aromatic vinyl compound units A polymer block (however, the content of the aromatic vinyl compound unit is 45% by mass or less, preferably 40% by mass or less), and the vinyl bond content in the conjugated diene compound unit is 60% or more. A polymer block [polymer block d] a tapered block containing a conjugated diene compound unit and an aromatic vinyl compound unit, wherein the aromatic vinyl compound unit is gradually increased. [Ac-d] (wherein a represents polymer block a, c represents polymer block c, and d represents polymer block d). It has a structure.
In the polymer block c, the vinyl bond content is 60% or more, preferably 65% or more, more preferably 70% or more. If the vinyl bond content is less than 60%, the pressure-sensitive adhesive composition is inferior in adhesive strength, which is not preferable.
In the polymer block d, the mass ratio of the aromatic vinyl compound / conjugated diene compound unit is preferably 70/30 to 95/5, more preferably 85/15 to 95/5.
In the copolymer before hydrogenation, the mass ratio of the aromatic vinyl compound unit and the conjugated diene compound unit is aromatic vinyl compound unit / conjugated diene compound unit = 5/95 to 60/40, preferably 5 / It is 95-40 / 60, More preferably, it is 10 / 90-30 / 70.

A hydrogenated copolymer obtained by hydrogenating such a pre-hydrogenated copolymer (component (C)) is, for example, [A-C-D] (where A is a polymer derived from the polymer block a). The polymer block, c is a polymer block derived from the polymer block c, and d is a polymer block derived from the polymer block d.
The hydrogenation rate of the hydrogenated copolymer used as the component (c) is 80% or more, preferably 90% or more, more preferably 95% or more. When the hydrogenation rate is less than 80%, the heat resistance and weather resistance are inferior, the adhesive strength when applied for a long time is remarkably increased, and an adhesive residue tends to be generated at the time of peeling.
The melt flow rate of the hydrogenated copolymer measured at 230 ° C. and 21.2 N load is preferably 0.01 to 100 g / 10 minutes, more preferably 0.01 to 80 g / 10 minutes.

[(D) ingredient]
The component (d) includes the following polymer block e and the following polymer block f, e- (fe) _n , or (ef) _m (where e is the polymer block e, f is Polymer blocks f, n and m each independently represent an integer of 1 or more), wherein the mass ratio of polymer block e to polymer block f is e / f = This is a hydrogenated copolymer obtained by hydrogenating a block copolymer of 5/95 to 50/50 so that the hydrogenation rate is 80% or more.
[Polymer block e] Polybutadiene block having a vinyl bond content of 30% or less [Polymer block f] Polymer block having a conjugated diene compound unit and a vinyl bond content of 60% or more (D) Component As the copolymer before hydrogenation, those having a structure represented by the above [e−f] _m are preferable from the viewpoint of productivity.
The polymer block e constituting the pre-hydrogenation copolymer is a polybutadiene block obtained by homopolymerizing butadiene. In the polymer block e, the vinyl bond content is 30% or less, preferably 20% or less.
The polymer block f constituting the copolymer before hydrogenation is a polymer block composed of a conjugated diene compound unit and other repeating units (for example, an aromatic vinyl compound unit).
The content of the conjugated diene compound unit in the polymer block f is preferably 70% by mass or more, more preferably 80% by mass or more.
In the polymer block f, the vinyl bond content is 60% or more, preferably 70% or more.
In the copolymer before hydrogenation, the mass ratio of the polymer block e to the polymer block f is e / f = 5/95 to 50/50, preferably 20/80 to 50/50.

A hydrogenated copolymer obtained by hydrogenating such a pre-hydrogenated copolymer (component (d)) is E- [FE] _n or [EF] _m (where E is heavy). The polymer block derived from the combined block e, F represents a polymer block derived from the polymer block f, and n and m represent an integer of 1 or more. (D) As a hydrogenated copolymer used as a component, what has a structure represented by the said [EF] _m from a viewpoint of productivity is preferable.
The hydrogenation rate of the hydrogenated copolymer used as the component (d) is 80% or more, preferably 90% or more, more preferably 95% or more.
The melt flow rate of the hydrogenated copolymer measured at 230 ° C. and 21.2 N load is preferably 0.01 to 100 g / 10 minutes, more preferably 0.01 to 80 g / 10 minutes.

[(E) component]
The component (e) includes the following polymer block a (the definition and details of the polymer block a are the same as those of the polymer block a in the component (a)), the following polymer block g, and the following polymer block e. (The definition and details of the polymer block e are the same as those of the polymer block e in the component (d)), and the polymer block a, the polymer block g, and the polymer block In the total 100% by mass of e, the content of the polymer block a is 5 to 40% by mass, the content of the polymer block g is 30 to 90% by mass, and the content of the polymer block e is 5 to 40% by mass. This is a hydrogenated copolymer obtained by hydrogenating a certain block copolymer so that the hydrogenation rate is 80% or more.
[Polymer block a] A polymer block mainly composed of an aromatic vinyl compound unit [Polymer block g] containing 55 to 100% by mass of a conjugated diene compound unit and 45 to 0% by mass of an aromatic vinyl compound unit. Polymer block having a vinyl bond content of 40% or more in the diene compound unit [polymer block e] Polybutadiene block having a vinyl bond content of 30% or less. Vinyl bond content in each of the polymer blocks a and e The conditions such as the content of the aromatic vinyl compound unit and the type of the monomer are the same as those in the above-mentioned component (a) and component (d).
The polymer block g constituting the pre-hydrogenation copolymer of the component (e) contains 55 to 100% by mass of conjugated diene compound units and 45 to 0% by mass of aromatic vinyl compound units. A polymer block having a vinyl bond content of 40% or more.
In the polymer block g, the content of the conjugated diene compound unit is 55 to 100% by mass, preferably 65 to 100% by mass, more preferably 75 to 100% by mass, and most preferably 80 to 100% by mass.
In the polymer block g, the content of the aromatic vinyl compound unit is 0 to 45% by mass, preferably 0 to 35% by mass, more preferably 0 to 25% by mass, and most preferably 0 to 20% by mass.
By making the content rate of a conjugated diene compound unit and an aromatic vinyl compound unit into said numerical range, the softness | flexibility of an adhesive composition can be improved.
In addition, the other monomer (for example, (meth) acrylic acid ester compound etc.) which comprises repeating units other than a conjugated diene compound unit and an aromatic vinyl compound unit can also be used. The content of other monomers in the polymer block b is preferably 10% by mass or less, more preferably 5% by mass or less.
In the polymer block g, the vinyl bond content is 40% or more, preferably 40 to 90%, more preferably 40 to 85%. By setting the vinyl bond content within the above range, a pressure-sensitive adhesive composition having an excellent balance between tack and adhesive strength can be obtained.
The content of each polymer block in a total of 100% by mass of the polymer block a, the polymer block g, and the polymer block e is as follows.
The content rate of the polymer block a is 5-40 mass%, Preferably it is 5-30 mass%.
The content rate of the polymer block g is 30-90 mass%, Preferably it is 40-80 mass%.
The content rate of the polymer block e is 5-40 mass%, Preferably it is 10-35 mass%.

A hydrogenated copolymer (component (e)) obtained by hydrogenating such a pre-hydrogenated copolymer is, for example, [E-GA] (where E is derived from the polymer block e). A polymer block, G has a structure represented by a polymer block derived from the polymer block g, and A represents a polymer block derived from the polymer block a.
The hydrogenation rate of the hydrogenated copolymer used as the component (e) is 80% or more, preferably 90% or more, more preferably 95% or more.
The melt flow rate of the hydrogenated copolymer measured at 230 ° C. and 21.2 N load is preferably 0.01 to 100 g / 10 minutes, more preferably 0.01 to 80 g / 10 minutes.

[(F) component]
The component (f) includes the following polymer block a and the following polymer block b (the definition and details of the above polymer blocks a and b are the same as the polymer blocks a and b in the component (a)). Wherein the mass ratio of the polymer block a to the polymer block b is a / b = 5/95 to 45/55, and at least two terminals are the polymer block a. And a block copolymer having at least one polymer block b in the intermediate portion (excluding copolymers obtained by coupling. The block copolymer before hydrogenation is hereinafter referred to as before hydrogenation) Is a hydrogenated copolymer obtained by hydrogenating such that the hydrogenation rate is 80% or more.
The unhydrogenated copolymer, for _{example, [a 1 -b-a 2} ], [a 1 -b 1 -b 2 -a 2], [a 1 -b-a 2 -a 3], [a ₁ -b ₁ -b ₂ -b ₁ -a ₂ ] (where a ₁ , a ₂ , and a ₃ are polymer blocks that satisfy the conditions of the polymer block a, and b ₁ and b ₂ are the polymer block b. A polymer block that satisfies the following condition :). In these block copolymers, for example, a ₁ , a ₂ , a ₃ and b ₁ , b ₂ are related to the polymer block a and the polymer block b, and each is a different polymer block (for example, a ₁ , a ₂ and a ₃ may be different from each other) or the same polymer block (for example, a ₁ , a ₂ and a ₃ are all the same).
In the hydrogenated copolymer, the mass ratio of the polymer block a and the polymer block b is a / b = 5/95 to 45/55, preferably 10/90 to 35/65. .

Hydrogenated copolymers (component (f)) obtained by hydrogenating such a pre-hydrogenated copolymer are, for example, [A ₁ -B-A ₂ ], [A ₁ -B ₁ -B _2- A ₂ ], [A ₁ -BA ₂ -A ₃ ], [A ₁ -B ₁ -B ₂ -B ₁ -A ₂ ] and the like. (However, A ₁ , A ₂ and A ₃ are polymer blocks derived from the polymer block a, and B ₁ and B ₂ are polymer blocks derived from the polymer block b). In these block copolymers, for example, A ₁ , A ₂ , A ₃ and B ₁ , B ₂ are related to the polymer blocks A and B, and each is a different polymer block (for example, A ₁ , A ₂ , A ₃ may be all different, or may be the same polymer block (for example, A ₁ , A ₂ , and A ₃ are all the same).
In addition, it is preferable that the terminal polymer block A occupies 2 mass% or more of the whole copolymer. This is to ensure that the effect of the polymer block A is exhibited.
The hydrogenation rate of the hydrogenated copolymer used as the component (f) is 80% or more, preferably 90% or more, more preferably 95% or more.
The melt flow rate of the hydrogenated copolymer measured at 230 ° C. and 21.2 N load is preferably 0.01 to 100 g / 10 minutes, more preferably 0.01 to 80 g / 10 minutes.

[Copolymer composition]
The copolymer composition (collection of one or more copolymers) constituting the pressure-sensitive adhesive composition of the present invention comprises (a) component as an essential component, preferably at least (b) component and (B) It contains a component.
The content of the component (A) in the copolymer composition is 50% by mass or more, preferably from the viewpoint of suppressing adhesion progress, with the total amount of the component (A) and the component (B) being 100% by mass. It is 55 mass% or more, More preferably, it is 60 mass% or more.
The copolymer composition may further contain one or more selected from the above (c) component, the above (d) component, the above (e) component, and the above (f) component.
In the copolymer composition, the mass ratio of the total blending amount of the component (A) and the component (B) and the blending amount of the component (C) is ((I) + (B)) / (C) = 10/90 to 90/10, preferably 30/70 to 90/10, more preferably 50/50 to 90/10.
In the copolymer composition, the mass ratio of the total blending amount of the component (a) and the component (b) and the blending amount of the component (d) is ((b) + (b)) / (d) = 10/90 to 90/10, preferably 30/70 to 90/10, more preferably 50/50 to 90/10.
In the copolymer composition, the mass ratio of the total amount of the component (a) and the component (b) and the amount of the component (e) is ((b) + (b)) / (e) = 10/90 to 90/10, preferably 30/70 to 90/10, more preferably 50/50 to 90/10.
In the copolymer composition, the mass ratio of the total blending amount of the component (b) and the component (b) and the blending amount of the component (f) is ((b) + (b)) / (f) = 10/90 to 90/10, preferably 30/70 to 90/10, more preferably 50/50 to 90/10.

In the copolymer composition, the mass ratio (A / B) between the polymer block A and the polymer block B is preferably 5/95 to 25/75, more preferably 5/95 to 20/80, More preferably, it is 5 / 95-15 / 85. When the mass ratio of the polymer block A and the polymer block B is within the above range, an appropriate holding force can be imparted to the pressure-sensitive adhesive layer to be formed, and the surface of the adherend has an uneven surface. Even in the case where there is, the pressure-sensitive adhesive layer exhibits good followability with respect to the concavo-convex processed surface, so that the surface of the adherend can be reliably protected.
In the copolymer composition, the content of the aromatic vinyl compound unit is preferably 5% by mass or more and less than 25% by mass, more preferably 5 to 20% by mass, It is especially preferable to set it within the range of 7 to 20% by mass. By setting the content of the aromatic vinyl compound unit within the above range, it is possible to obtain a pressure-sensitive adhesive composition having both an appropriate holding power and the ability to follow the uneven surface of the adherend.

  The molecular weight of the copolymer composition is not particularly limited, but the weight average molecular weight is preferably 30,000 to 500,000, more preferably 80,000 to 300,000, and 100,000 to 200,000. Is particularly preferred. By making the weight average molecular weight in the range of 30,000 to 500,000, industrial production of the copolymer composition can be facilitated. If the weight average molecular weight is less than 30,000, the polymer may adhere to the production equipment in the step of removing the solvent and drying the polymer, making industrial production of the copolymer composition difficult. On the other hand, when the weight average molecular weight exceeds 500,000, the solubility in a solvent and the heat melting property are deteriorated, and the formation of the pressure-sensitive adhesive layer may be difficult.

The value of the melt flow rate (hereinafter referred to as “MFR (230 ° C., 21.2 N)”) measured at a load of 230 ° C. and 21.2 N of the copolymer composition is 1 to 100 g / 10 min. It is preferable to be within the range. By setting the value of MFR (230 ° C., 21.2 N) within the above range, the extrusion moldability of the pressure-sensitive adhesive composition, and thus the productivity can be greatly improved.
In order to further improve the extrusion moldability, it is preferable to set the MFR (230 ° C., 21.2 N) value of the copolymer composition within the range of 1 to 50 g / 10 minutes. In addition, the value of MFR (230 degreeC, 21.2N) is a weight average molecular weight, mass ratio of (A) component and (B) component, content of an aromatic vinyl compound unit, (I) component, and (B) It can control by conditions, such as a vinyl bond content rate of a conjugated diene compound unit contained in a component, and a hydrogenation rate. In this specification, “MFR (230 ° C., 21.2 N)” means an MFR value measured according to the method described in JIS K7210.

  The copolymer composition preferably has a tan δ (80 ° C.) value of 0.10 or more. By setting the value of tan δ (80 ° C.) to 0.10 or more, it is possible to improve the problem of floating of the pressure-sensitive adhesive layer. Considering the balance with heat resistance, the value of tan δ (80 ° C.) is preferably in the range of 0.10 to 0.50, and more preferably in the range of 0.10 to 0.20. The value of tan δ (80 ° C.) is controlled by the conditions such as the content of the aromatic vinyl compound unit, the vinyl bond content of the conjugated diene compound unit contained in the component (a) and component (b), and the hydrogenation rate. be able to.

  The copolymer composition preferably has a tan δ (20 ° C.) value of 0.15 or less. By setting the value of tan δ (20 ° C.) to 0.15 or less, the high-speed peelability can be improved. The value of tan δ (20 ° C.) can be controlled by conditions such as the vinyl bond content and hydrogenation rate of the conjugated diene compound unit contained in the component (a) or component (b).

Further, the copolymer composition preferably has a G ′ (20 ° C.) value of 1.8 × 10 ⁶ Pa or less. By setting the value of G ′ (20 ° C.) to 1.8 × 10 ⁶ Pa or less, an appropriate adhesive force can be obtained.
However, considering the productivity, it is more preferable that the value of G ′ (20 ° C.) is in the range of 1.0 × 10 ^{5 to} 1.5 × 10 ⁶ Pa. The value of G ′ (20 ° C.) is controlled by conditions such as the content of aromatic vinyl compound units, the vinyl bond content of the conjugated diene compound units contained in component (a) and component (b), and the hydrogenation rate. can do.
In this specification, “tan δ (80 ° C.)”, “tan δ (20 ° C.)”, and “G ′ (20 ° C.)” are trade names: ARES measuring instrument (manufactured by TA Instruments Inc.) ), The value of dynamic viscoelasticity measured under the conditions of temperature dispersion range of −60 to 100 ° C., heating rate of 5 ° C./min, strain of 0.14%, frequency of 10 Hz.

[Optional ingredients]
In the pressure-sensitive adhesive composition of the present invention, an example of an optional component that can be blended with the copolymer composition includes a tackifier. By blending a tackifier, the initial adhesive strength of the pressure-sensitive adhesive composition can be improved.
Examples of the tackifier include petroleum-based resins such as aliphatic copolymers, aromatic copolymers, aliphatic / aromatic copolymer systems and alicyclic copolymers, and coumarone-indene resins. , Terpene resins, terpene phenol resins, rosin resins such as polymerized rosin, (alkyl) phenol resins, xylene resins or hydrogenated products thereof, etc. Can be used without any particular limitation. These tackifiers may use only 1 type and may use 2 or more types together.

  Other examples of optional components that can be blended in the pressure-sensitive adhesive composition of the present invention include polyolefin resins, antioxidants, ultraviolet absorbers, colorants, light stabilizers, thermal polymerization inhibitors, antifoaming agents, and leveling. Agents, antistatic agents, surfactants, storage stabilizers, fillers and the like.

  The blending ratio of the optional component (for example, tackifier, etc.) in the pressure-sensitive adhesive composition of the present invention is preferably 0 to 30% by mass, more preferably 0 to 20% by mass.

In the pressure-sensitive adhesive composition of the present invention, the increase in peel strength when left in a 40 ° C. atmosphere for 7 days is 0.55 N / 10 mm or less, preferably 0.50 N / 10 mm or less.
The increase value of the peel strength is measured as follows.
An adhesive body (25 mm × 300 mm × 0.1 mm (thickness)) in which an adhesive layer made of an adhesive composition is formed on a substrate (polyolefin film) is used as a test piece. This test piece is measured in accordance with JIS Z0237 for initial peel strength. The test piece is left in an atmosphere of 40 ° C. for 7 days, and the peel strength is measured again. The difference between the peel strength and the initial peel strength is defined as an increase value of the peel strength.

[Production method]
As the method for producing the pressure-sensitive adhesive composition of the present invention, after obtaining a mixture comprising the component (a) and the component (b) by a coupling method, the mixture is blended with the above-mentioned (c) The method of mixing arbitrary components, such as a)-(f) component, is preferable. According to this method, the component (a) and the component (b) can be synthesized in one pot, so that the manufacturing process can be simplified and the manufacturing cost can be reduced. Further, by appropriately determining the type and amount of the coupling agent, the ratio of the component (A) to the component (B) can be easily controlled to a desired value.
Specifically, first, component (a) and component (b) are simultaneously produced by a coupling method.
The coupling method includes a first step: a step of synthesizing a copolymer having a structure of [a-b] (a copolymer ((b)) before hydrogenation) by a block polymerization, and a second step: the above [ a part of the copolymer having the structure ab] is converted into a coupling agent YZ _x (wherein Y is a coupling agent residue, Z is a leaving group, and X is an integer of 2 or more). And a step of synthesizing a copolymer having a structure of [a-b] _x- Y (a copolymer before component (i) before hydrogenation), and a third step: Hydrogenation of the copolymer having the structure [A-B] by hydrogenating the copolymer having the structure and the copolymer having the structure [ab] _x -Y (component (B)) and prepared _{{[a-B] x -Y} } hydrogenated copolymer having a structure of (component (i)), I and a component (i) and (ii) component It is intended to include a step of obtaining a copolymer composition.

  Examples of the coupling agent include methyldichlorosilane, dimethyldichlorosilane, methyltrichlorosilane, butyltrichlorosilane, tetrachlorosilane, dibromoethane, tetrachlorotin, butyltrichlorotin, tetrachlorogermanium, and bis (trichlorosilyl) ethane. Halogen compounds of the following: epoxy compounds such as epoxidized soybean oil; carbonyl compounds such as diethyl adipate, dimethyl adipate, dimethyl terephthalic acid, diethyl terephthalic acid; polyvinyl compounds such as divinylbenzene; polyisocyanate; Of these, methyldichlorosilane, dimethyldichlorosilane, methyltrichlorosilane, and tetrachlorosilane are preferred because they are easily industrially available and have high reactivity.

As the hydrogenation catalyst, a compound containing any one of Group Ib, IVb, Vb, VIb, VIIb, and Group VIII metals can be used. Examples thereof include compounds containing Ti, V, Co, Ni, Zr, Ru, Rh, Pd, Hf, Re, and Pt atoms, and more specifically, Ti, Zr, Hf, Co, Ni, Rh. And metallocene compounds such as Ru, and supported heterogeneous catalysts in which metals such as Pd, Ni, Pt, Rh, and Ru are supported on a support such as carbon, silica, alumina, diatomaceous earth, and basic activated carbon. it can.
Specific examples of metallocene compounds include Kaminsky catalyst, ansa metallocene catalyst, non-bridged half, having two ligands in which Cp ring or hydrogen on Cp ring is substituted with an alkyl group. A metallocene catalyst, a bridge | crosslinking half metallocene catalyst, etc. can be mentioned.

In addition, a homogeneous Ziegler catalyst in which an organic salt or acetylacetone salt of a metal element such as Ni or Co and a reducing agent such as organoaluminum are combined, or an organometallic compound such as Ru or Rh can be given.
Among these hydrogenation catalysts, metallocene compounds containing any of Ti, Zr, Hf, Ni, Co, Ru, and Rh are preferable, and metallocene compounds containing any of Ti, Zr, and Hf are more preferable. In addition, a catalyst obtained by reacting a titanocene compound with alkoxylithium is an inexpensive and industrially particularly useful catalyst, and is particularly preferable.

  Specific examples of the hydrogenation catalyst include JP-A-1-275605, JP-A-5-271326, JP-A-5-271325, JP-A-5-222115, and JP-A-11-292924. JP, 2000-37632, JP 59-133203, JP 63-5401, JP 62-218403, JP 7-90017, JP 43-19960. And the catalyst described in Japanese Patent Publication No. 47-40473. These various catalysts may be used alone or in combination of two or more.

Next, the components (a) to (f) and others synthesized separately from the components (a) and (b) with respect to the mixture of the components (a) and (b) obtained by the above coupling method Are added as necessary to obtain a pressure-sensitive adhesive composition.
The production method of each of the above components (c) to (f) is not particularly limited and can be synthesized by a known method. For example, the components are produced by the following method.
Polymerization of an organic alkali metal compound in an organic solvent is started in a polymer block constituting the copolymer before hydrogenation (for example, in the case of component (c), polymer block a, polymer block b, and polymer block d). Living anion polymerization as an agent to obtain a block copolymer (copolymer before hydrogenation), and further hydrogenating this block copolymer, any component of the copolymer composition (for example, ( C) Component) is obtained.
As the organic solvent, hydrocarbon solvents such as pentane, hexane, heptane, octane, methylcyclopentane, cyclohexane, benzene and xylene are used.
As the organic alkali metal compound which is a polymerization initiator, an organic lithium compound is preferable.
As the organic lithium compound, an organic monolithium compound, an organic dilithium compound, or an organic polylithium compound is used. Specific examples thereof include ethyl lithium, n-propyl lithium, isopropyl lithium, n-butyl lithium, sec-butyl lithium, t-butyl lithium, hexamethylene dilithium, butadienyl lithium, and isoprenyl dilithium. For example, it is used in an amount of 0.02 to 0.2 parts by weight per 100 parts by weight of the monomer.
At this time, examples of the regulator of the microstructure (vinyl bond content of the conjugated diene moiety) include Lewis bases such as ethers and amines.
Among these, examples of the ether include ether derivatives of polyethylene glycol such as diethyl ether, tetrahydrofuran, propyl ether, butyl ether, higher ether, or ethylene glycol dibutyl ether, diethylene glycol dimethyl ether, diethylene glycol dibutyl ether, and triethylene glycol dimethyl ether. . Examples of the amine include tertiary amines such as tetramethylethylenediamine, pyridine, and tributylamine.
The microstructure modifier is used with the organic solvent.
The polymerization reaction is usually performed at -30 ° C to 150 ° C.
Further, the polymerization may be carried out while controlling at a constant temperature, or may be carried out under an increase in temperature without removing heat.
Examples of the catalyst used for hydrogenation include those described above.

[Adhesive layer-containing member (surface protective film, etc.)]
The pressure-sensitive adhesive layer-containing member of the present invention (for example, a surface protective film) is provided with a base material and a pressure-sensitive adhesive layer formed by being laminated on the surface of the base material, and the pressure-sensitive adhesive layer is The pressure-sensitive adhesive composition of the present invention is included.

  Examples of the base material include inorganic materials such as metals and glasses; synthetic resin materials such as polyolefin resins and polyester resins; and base materials made of materials such as cellulose materials. These base materials may be used independently, and the laminated body which laminated | stacked 2 or more types of base materials may be used. Among these base materials, a base material made of a polyolefin resin is preferably used from the viewpoints of productivity, handling properties, and cost. The thickness of the base material is not particularly limited, but when the adhesive layer and the base material are deformed and handled like a roll, it is preferably 1.0 mm or less, and more preferably 300 μm or less. , 100 μm or less is particularly preferable. The lower limit is preferably 10 μm, more preferably 20 μm, from the viewpoint of practicality.

  The method for producing the pressure-sensitive adhesive layer-containing member is not particularly limited. For example, the pressure-sensitive adhesive composition is laminated on the surface of the formed synthetic resin base material, and the base material and the pressure-sensitive adhesive layer are laminated. The base material and the pressure-sensitive adhesive layer can be obtained by co-extrusion of a method of integrating or a pressure-sensitive adhesive composition for forming a pressure-sensitive adhesive layer and a resin composition for forming a base material made of synthetic resin. A method of stacking and integrating can be mentioned.

As a method of laminating the pressure-sensitive adhesive composition to a synthetic resin base material, for example, a solution coating method for applying a solution of the pressure-sensitive adhesive composition, a dry lamination method, an extrusion coating method using a T-die, or the like is used. Can do. In this case, in order to increase the bonding strength between the base material layer and the pressure-sensitive adhesive layer, it is preferable to subject the synthetic resin base material to a surface treatment such as corona discharge or primer coating in advance.
Moreover, as a method of laminating and integrating a resin composition for a base material made of a synthetic resin and a pressure-sensitive adhesive composition by coextrusion, a conventionally known method such as an inflation method or a T-die method can be used. . Among these methods, the coextrusion method by the T-die method, which can economically manufacture a high-quality pressure-sensitive adhesive layer-containing member, is most preferable.

Although the thickness of an adhesive layer is not specifically limited, It is desirable that it is the range of 3-50 micrometers. If the thickness is less than 3 μm, the adhesive strength may be insufficient, and if it exceeds 50 μm, the cost may increase.
The pressure-sensitive adhesive layer-containing member (for example, a surface protective film) of the present invention is suitable as an optical surface protective film.

  Hereinafter, the pressure-sensitive adhesive composition and the pressure-sensitive adhesive layer-containing member of the present invention will be described more specifically using examples. However, these examples merely show examples of embodiments of the present invention. Accordingly, the present invention should not be construed as limited to these examples. In addition, unless otherwise indicated, the part and% in an Example and a comparative example are mass references | standards.

[Preparation of copolymer composition]
(Copolymer composition 1)
A nitrogen-substituted reaction vessel is charged with 500 parts by mass of degassed / dehydrated cyclohexane, 10 parts by mass of styrene and 5 parts by mass of tetrahydrofuran, and 0.13 parts by mass of n-butyllithium is added at a polymerization start temperature of 40 ° C. Then, temperature rising polymerization was performed. After the polymerization conversion rate reached approximately 100%, the reaction solution was cooled to 15 ° C., and then 87 parts by mass of 1,3-butadiene and 3 parts by mass of styrene were added, followed by temperature rising polymerization.
After the polymerization conversion rate reached approximately 100%, 0.07 parts by mass of methyldichlorosilane was added as a coupling agent to carry out a coupling reaction. After the coupling reaction was completed, it was left for 10 minutes while supplying hydrogen gas at a pressure of 0.4 MPa-Gauge. When a part of the polymer taken out was analyzed by GPC, the weight average molecular weight was about 170,000.
Thereafter, 0.03 parts by mass of diethylaluminum chloride and 0.06 parts by mass of bis (cyclopentadienyl) titanium furfuryloxychloride were added to the reaction vessel and stirred. When the hydrogenation reaction was started at a hydrogen gas supply pressure of 0.7 MPa-Gauge and a reaction temperature of 80 ° C. and the absorption of hydrogen was completed, the reaction solution was returned to room temperature and normal pressure, and then extracted from the reaction vessel. The copolymer composition 1 which consists of a component and (b) component was obtained. The copolymer composition 1 includes a copolymer (A-1) having a structure of [AB] ₂ -Y (Y is a coupling agent residue) as the component (A) and a component (B) as [B] And a copolymer (B-1) having a structure of A-B].

(Copolymer composition 2, 8, 9)
[A-B] ₂ -Y in the same manner as the copolymer composition 1 except that the amount of the monomer (styrene, 1,3-butadiene), coupling agent, catalyst, and the like was appropriately adjusted. A copolymer having a structure of (Y is a coupling agent residue) (A-1) (component (A)), and a copolymer having a structure of [AB] (B-1) ((B) Copolymer compositions 2, 8 and 9 comprising
(Copolymer composition 3, 4, 10)
[A-B] ₂ -Y in the same manner as the copolymer composition 1 except that the amount of the monomer (styrene, 1,3-butadiene), coupling agent, catalyst, and the like was appropriately adjusted. A copolymer having a structure of (Y is a coupling agent residue) (I-2) (component (A)) and a copolymer having a structure of [AB] (B-2) ((B) Copolymer compositions 3, 4 and 10 comprising
(Copolymer compositions 5-7, 11)
[AB] ₂ -Y (Y is a cup) in the same manner as in Preparation Example 1 except that the amount of the monomer (styrene, 1,3-butadiene), coupling agent, catalyst, and the like was appropriately adjusted. A copolymer having a structure of a ring agent residue (a-3) (component (a)) and a copolymer having a structure [AB] (ro-3) (component (b)) Copolymer compositions 5 to 7 and 11 were obtained.
(Copolymer composition 12)
A nitrogen-substituted reaction vessel is charged with 500 parts by mass of degassed and dehydrated cyclohexane, 10 parts by mass of styrene and 5 parts by mass of tetrahydrofuran, and 0.10 parts by mass of n-butyllithium is added at a polymerization start temperature of 40 ° C. Then, temperature rising polymerization was performed. After the polymerization conversion rate reached approximately 100%, the reaction solution was cooled to 25 ° C., and then 87 parts by mass of 1,3-butadiene and 3 parts by mass of styrene were added, followed by temperature-increasing polymerization.
After the polymerization conversion rate reached approximately 100%, hydrogen gas was allowed to stand for 10 minutes while being supplied at a pressure of 0.4 MPa-Gauge. When a partly taken out polymer was analyzed by GPC, the weight average molecular weight was about 130,000. Thereafter, 0.04 part by mass of tetrachlorosilane was added to the reaction vessel and stirred. When the hydrogenation reaction was performed under the same conditions as in Preparation Example 1 and the absorption of hydrogen was completed, the reaction solution was returned to room temperature and normal pressure, and then extracted from the reaction vessel, whereby a co-polymer having an [AB] structure. A copolymer composition 12 composed of the polymer (B-1) was obtained.

Table 1 shows the physical properties of the copolymers (I-1) to (I-3) and the copolymers (B-1) to (B-3) constituting the obtained copolymer compositions 1 to 12. .
In Table 1, “ab” or “abc” (a, b, and c are numbers) described as “mass ratio of each block” is “(copolymer block) (Mass of A)-(mass of copolymer block B) "(a-1 to i-3, b-1 to b-3)," (mass of copolymer block A)-(copolymer block C) Mass)-(mass of copolymer block D) "(c-1)," (mass of copolymer block E)-(mass of copolymer block F) "(d-1)," (copolymer (Mass of polymer block E)-(mass of copolymer block B)-(mass of copolymer block A) "(e-1)," (mass of copolymer block A)-(copolymer block) B (mass of B)-(mass of copolymer block A) "(f-1, f-2).

(Copolymer composition 13)
A nitrogen-substituted reaction vessel is charged with 500 parts by mass of degassed and dehydrated cyclohexane, 15 parts by mass of styrene and 5 parts by mass of tetrahydrofuran, and 0.10 parts by mass of n-butyllithium is added at a polymerization start temperature of 40 ° C. Then, temperature rising polymerization was performed. After the polymerization conversion rate reached approximately 100%, the reaction solution was cooled to 15 ° C., and then 75 parts by mass of 1,3-butadiene was added, followed by further temperature rising polymerization.
After the polymerization conversion rate reached approximately 100%, 10 parts by mass of styrene was added, and further polymerization was performed. After the polymerization conversion rate reached approximately 100%, hydrogen gas was allowed to stand for 10 minutes while being supplied at a pressure of 0.4 MPa-Gauge. When a partly taken out polymer was analyzed by GPC, the weight average molecular weight was about 130,000. Thereafter, a hydrogenation reaction is carried out under the same conditions as in Preparation Example 1, and when the absorption of hydrogen is completed, the reaction solution is returned to room temperature and normal pressure, and is taken out from the reaction vessel to obtain the [ABA] structure. As a result, a copolymer composition 13 comprising a copolymer (f-1) having
(Copolymer composition 14)
A copolymer having a structure of [ABA] in the same manner as the copolymer composition 13 except that the blending amount of a monomer (styrene, 1,3-butadiene), a catalyst and the like is appropriately adjusted. A copolymer composition 14 comprising (F-2) was obtained.
Table 1 shows the physical properties of the copolymers (f-1) and (f-2).

(Copolymer composition 15-17)
A composition 15 comprising the copolymer (C-1), in the same manner as the copolymer composition 13 except that the blending amount of the monomer (styrene, 1,3-butadiene), catalyst, etc. was appropriately adjusted. Each of the composition 16 consisting of a copolymer (d-1) and the composition 17 consisting of a copolymer (e-1) was obtained.
Table 1 shows the physical properties of the copolymer (c-1), the copolymer (d-1), and the copolymer (e-1).
In addition, evaluation of the physical property of the said copolymer is based on the following method.
(1) Mass ratio of polymer block A and polymer block B (A / B ratio)
The mass ratio of the polymer block A and the polymer block B was calculated from the amount of raw material charged when the copolymer was produced.
(2) Content of 1,2-vinyl bond and 3,4-vinyl bond (vinyl bond content)
It was calculated by the Morero method using the infrared absorption spectrum method.
(3) Hydrogenation rate of conjugated diene compound unit (hydrogenation rate)
Calculation was performed from 270 MHz, ¹ H-NMR spectrum using carbon tetrachloride as a solvent.
(4) MFR (230 ° C, 21.2N)
Based on the method described in JIS K7210, the measurement was performed under conditions of 230 ° C. and 21.2 N load.

Example 1
As the copolymer composition, the above-described copolymer composition 1 (consisting of the components (A) and (B)) was used, and tetrahydrofuran was added to obtain a tetrahydrofuran solution. Thereafter, a base material (PP film having a thickness of 80 μm) whose surface was previously subjected to corona discharge treatment was prepared, and the tetrahydrofuran solution was applied to the surface of the base material which had been subjected to corona discharge treatment, dried and thickened. A pressure-sensitive adhesive layer having a thickness of 20 μm was formed to obtain a pressure-sensitive adhesive layer-containing member (surface protective film) in which the pressure-sensitive adhesive layer was formed on the surface of the substrate. This pressure-sensitive adhesive layer-containing member was used as a roll-shaped wound body, and the physical properties were evaluated by the following methods. The results are shown in Table 2.
(Peel strength)
In accordance with JIS Z0237, a test piece was prepared and the initial peel strength was measured. Moreover, after leaving the test piece in a 40 degreeC atmosphere for 7 days, peel strength was measured again and the raise value with respect to initial peel strength was calculated | required.
Moreover, in the copolymer composition 1 used in Example 1, the mass ratio of the component (A) (copolymer (I-1)) and the component (B) (copolymer (B-1)). Is shown in Table 2. The mass ratio of component (a) to component (b) was determined by the following method.
By separating the waveforms obtained by measurement by gel permeation chromatography (GPC, trade name: HLC-8120GPC, manufactured by Tosoh Finechem Co., Ltd.), the mass ratio of (A) / (B) was calculated.

(Examples 2-7, Comparative Examples 2-5)
An experiment was conducted in the same manner as in Example 1 except that the copolymer composition described in Table 2 (consisting of the components (A) and (B)) was used as the copolymer composition. The results are shown in Table 2.
Table 2 also shows the mass ratio of the component (A) and the component (B) in the composition.
(Comparative Example 1)
An experiment was conducted in the same manner as in Example 1 except that the copolymer composition 12 (composition comprising the copolymer (B-1)) was used. The results are shown in Table 2.

(Examples 8 and 9)
Copolymer composition 3 (composition consisting of copolymer (b-2) and copolymer (b-2)) and copolymer composition 15 (composition consisting of copolymer (c-1)) An experiment was carried out in the same manner as in Example 1 except that a mixture of (a mass ratio is shown in Table 3) was used. The results are shown in Table 3.
(Example 10)
Copolymer composition 3 (composition consisting of copolymer (b-2) and copolymer (b-2)) and copolymer composition 16 (composition consisting of copolymer (d-1)) An experiment was carried out in the same manner as in Example 1 except that a mixture of (a mass ratio is shown in Table 3) was used. Table 3 shows the results.
(Example 11)
Mixture of copolymer composition 3 (composition consisting of copolymer (ii-2) and copolymer (b-2)) and composition 17 (composition consisting of copolymer (e-1)) The experiment was performed in the same manner as in Example 1 except that the mass ratio is shown in Table 3. The results are shown in Table 3.
(Example 12)
Mixture of copolymer composition 3 (composition comprising copolymer (ii-2) and copolymer (ro-2)) and composition 13 (composition comprising copolymer (f-1)) The experiment was performed in the same manner as in Example 1 except that the mass ratio is shown in Table 3. The results are shown in Table 3.
(Comparative Examples 6 to 10)
The experiment was performed in the same manner as in Example 1 except that the composition shown in Table 3 was used as the copolymer composition. The results are shown in Table 3.

  From Table 2 and Table 3, it can be seen that the pressure-sensitive adhesive composition of the present invention has a small increase in peel strength and is excellent in the effect of suppressing the progress of adhesive strength. On the other hand, it can be seen that the pressure-sensitive adhesive composition not belonging to the present invention has a high peel strength increase value, and the adhesive strength increases.

Claims (8)

A pressure-sensitive adhesive composition comprising the following component (a), wherein an increase in peel strength (standing at 40 ° C. for 7 days) is 0.55 N / 10 mm or less.
[Component (a)] The following polymer block a and the following polymer block b are included, and [ab] _x -Y (where a is the polymer block a, b is the polymer block b, and x is 2 or more. And Y represents a coupling agent residue.), Wherein the mass ratio of the polymer block a to the polymer block b is a / b = 5/95 to 45 Hydrogenated copolymer satisfying the following conditions (1) to (3) obtained by hydrogenating a / 55 block copolymer [polymer block a] a polymer block mainly composed of aromatic vinyl compound units [ Polymer Block b] A polymer block (1) containing 55 to 99% by mass of conjugated diene compound units and 45 to 1% by mass of aromatic vinyl compound units, and the vinyl bond content in the conjugated diene compound units is 60% or more (1 ) Weight average molecular weight 5-50 It is.
(2) The hydrogenation rate is 80% or more.
(3) The melt flow rate measured by 230 degreeC and a 21.2N load is 5-100 g / 10min. The pressure-sensitive adhesive composition according to claim 1, comprising the following component (b), wherein the blending amount of component (a) is 50% by mass or more in a total of 100% by mass of component (b) and component (b).
[(B) component] The following polymer block a and the following polymer block b are included, and [ab] _n (where a is a polymer block a, b is a polymer block b, and n is an integer of 1 to 3). Hydrogenated copolymer obtained by hydrogenating a block copolymer having the structure of [Polymer block a] Polymer block mainly composed of an aromatic vinyl compound unit [Polymer block b] Conjugated diene compound Polymer block containing 55 to 99% by mass of units and 45 to 1% by mass of aromatic vinyl compound units, and the vinyl bond content in the conjugated diene compound unit being 60% or more The following (c) component is included, and the mass ratio of the combined amount of the component (b) and the component (b) and the amount of the component (c) is ((b) + (b)) / The pressure-sensitive adhesive composition according to claim 2, wherein (C) = 10/90 to 90/10.
[Component (c)] A block copolymer comprising the following polymer block a, the following polymer block c, and the following polymer block d, wherein the mass ratio of the aromatic vinyl compound unit / conjugated diene compound unit is Hydrogenated copolymer satisfying the following condition (1) obtained by hydrogenating a block copolymer of 5/95 to 60/40 [polymer block a] a polymer block mainly composed of aromatic vinyl compound units [Polymer block c] A polymer block consisting only of a conjugated diene compound unit or a random copolymer block of a conjugated diene compound unit and an aromatic vinyl compound unit (however, the content of the aromatic vinyl compound unit is 45% by mass) The polymer block [polymer block d] conjugated die in which the content of vinyl bonds in the conjugated diene compound unit is 60% or more. And a compound units and aromatic vinyl compound unit, tapered block (1) the hydrogenation ratio of the aromatic vinyl compound unit gradually increases is 80% or more. The following (d) component is included, and the mass ratio of the combined amount of the component (b) and the component (b) and the amount of the component (d) is ((b) + (b)) / The pressure-sensitive adhesive composition according to claim 2, wherein (d) = 10/90 to 90/10.
[(D) Component] The following polymer block e and the following polymer block f are included, and e- (fe) _n or (ef) _m (where e is the polymer block e, f is Polymer blocks f, n and m each independently represent an integer of 1 or more), wherein the mass ratio of polymer block e to polymer block f is e / f = Hydrogenated copolymer obtained by hydrogenating a block copolymer of 5/95 to 50/50 satisfying the following condition (1) [polymer block e] polybutadiene having a vinyl bond content of 30% or less Block [polymer block f] A polymer block containing a conjugated diene compound unit, wherein the vinyl bond content in the conjugated diene compound unit is 60% or more (1) The hydrogenation rate is 80% or more. The following (e) component is included, and the mass ratio of the total amount of the component (a) and the component (b) and the amount of the component (e) is ((b) + (b)) / The pressure-sensitive adhesive composition according to claim 2, wherein (e) = 10/90 to 90/10.
[Component (e)] A block copolymer comprising the following polymer block a, the following polymer block g, and the following polymer block e, wherein the polymer block a, the polymer block g and the polymer block e In the total 100% by mass, the content of the polymer block a is 5 to 40% by mass, the content of the polymer block g is 30 to 90% by mass, and the content of the polymer block e is 5 to 40% by mass. Hydrogenated copolymer satisfying the following condition (1) obtained by hydrogenating the block copolymer [polymer block a] polymer block mainly composed of aromatic vinyl compound units [polymer block g] conjugated diene compound A polymer block [polymer block e] containing 55 to 100% by mass of units and 45 to 0% by mass of aromatic vinyl compound units, and having a vinyl bond content in the conjugated diene compound unit of 40% or more. Polybutadiene block (1) the hydrogenation ratio content of alkenyl bond is 30% or less is 80% or more. The following (f) component is included, and the mass ratio of the total amount of the component (b) and the component (b) and the amount of the component (f) is ((b) + (b)) / (F) = 10/90 to 90/10. The pressure-sensitive adhesive composition according to claim 2.
[(F) Component] A block copolymer comprising the following polymer block a and the following polymer block b, wherein the mass ratio of the polymer block a to the polymer block b is a / b = 5/95. A block copolymer having at least two ends of the polymer block a and having at least one polymer block b in the intermediate portion (excluding copolymers obtained by coupling) .) Is a hydrogenated copolymer that satisfies the following condition (1).
[Polymer block a] A polymer block mainly composed of an aromatic vinyl compound unit [Polymer block b] containing 55 to 100% by mass of a conjugated diene compound unit and 45 to 0% by mass of an aromatic vinyl compound unit. Polymer block having a vinyl bond content of 60% or more in the diene compound unit (1) The hydrogenation rate is 80% or more.   It is a surface protection film consisting of the base material layer which consists of polyolefin, and the adhesive layer formed by laminating | stacking on the single side | surface of this base material layer, Comprising: The said adhesive layer is any one of Claims 1-6. A surface protective film comprising the pressure-sensitive adhesive composition described in 1.   It is a method of manufacturing the surface protection film of Claim 7, Comprising: The manufacturing method of a surface protection film including the process of laminating | stacking the said base material layer and the said adhesive layer by extrusion molding.