JP2008274212A - 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. <P>SOLUTION: The composition comprises (i) a hydrogenated copolymer obtained by hydrogenating, with a hydrogenation rate of at least 80%, a block copolymer having a structure of [a-b]<SB>n</SB>(wherein a is a block containing at least 70 mass% of an aromatic alkenyl compound unit; b is a block containing at least 50 mass% of a conjugated diene compound unit and having a vinyl bond content of at least 60%; and n is an integer of 1-3) and containing at least 5 mass% and less than 30 mass% of the aromatic alkenyl compound unit and (ii) a hydrogenated copolymer obtained by hydrogenating, with a hydrogenation rate of at least 80%, a block copolymer having a structure of [a-b]<SB>x</SB>-Y (wherein a and b are the same as above; x is an integer of at least 2; and Y is a residue of a coupling agent) and containing at least 5 mass% and less than 30 mass% of the aromatic alkenyl compound unit so that the ratio of the component (ii) is at least 70 mass% and has a rise in peel strength (after kept at 40°C for 7 days) of at most 0.35 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.

  In general, the surface protective film has a configuration including a film-like base material and an adhesive layer formed on the surface of the base material. 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” The polymer block A, “B” indicates the polymer block B.) has already been disclosed (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.

That is, the present invention provides the following [1] to [10].
[1] A pressure-sensitive adhesive comprising the following component (a) and the following component (b), wherein the total amount of component (b) and component (b) is 100% by mass, and the compounding amount of component (b) is 70% by mass or more. A pressure-sensitive adhesive composition having a peel strength increase value (left in a 40 ° C. atmosphere for 7 days) of 0.35 N / 10 mm or less.
[Component (a)] 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). And a block copolymer having a content of aromatic alkenyl compound units of 5% by mass or more and less than 30% by mass is hydrogenated so that the hydrogenation rate is 80% or more. The hydrogenated copolymer [(B) component] comprises the following polymer block a and the following polymer block b, [ab] _x -Y (where a is the polymer block a and b is the polymer block b) , X represents an integer of 2 or more, and Y represents a coupling agent residue.) And a block copolymer having an aromatic alkenyl compound unit content of 5% by mass or more and less than 30% by mass. Hydrogenated co-polymerized by hydrogenation so that the hydrogenation rate is 80% or more Polymer [polymer block a] Polymer block having a content of aromatic alkenyl compound units of 70% by mass or more [Polymer block b] Content of conjugated diene compound units of 50% by mass or more, vinyl bond derived from conjugated diene compound The polymer block [2] having a content of 60% or more In each of the component (a) and the component (b), the content of the aromatic alkenyl compound unit is 5% by mass or more and less than 25% by mass. The pressure-sensitive adhesive composition according to the above [1].
[3] In each of the component (a) and the component (b), the polymer block a includes a styrene unit as an aromatic alkenyl compound unit, and the polymer block b includes a conjugated diene compound unit. The pressure-sensitive adhesive composition according to the above [1] or [2], comprising a 1,3-butadiene unit and / or an isoprene unit.
[4] The component (a) is composed of the polymer block a and the polymer block b, and [ab] (where a represents the polymer block a and b represents the polymer block b). The pressure-sensitive adhesive composition according to any one of the above [1] to [3], comprising a hydrogenated copolymer having the structure:
[5] The following (C) component is included, and the mass ratio of the total blending amount of (B) component and (B) component to the blending amount of (C) component is ((A) + (B) ) / (C) = 10/90 to 90/10, wherein the pressure-sensitive adhesive composition is any one of the above [1] to [4].
[Component (c)] A block copolymer comprising the following polymer block h, the following polymer block c, and the following polymer block d, wherein the mass ratio of the aromatic alkenyl compound unit / conjugated diene compound unit is Hydrogenated copolymer obtained by hydrogenating a block copolymer of 5/95 to 60/40 so that the hydrogenation rate is 80% or more [polymer block h] mainly comprising an aromatic alkenyl compound unit. Polymer block [polymer block c] Homopolymer block of conjugated diene compound or random copolymer block of conjugated diene compound and aromatic alkenyl compound (however, the content of aromatic alkenyl compound units is 45% by mass) And a polymer block [polymer block d] conjugated diene compound unit and an aromatic compound having a vinyl bond content of 60% or more. Tapered block including a kenyl compound unit and an aromatic vinyl compound unit gradually increasing [6] The following (d) component is included, and the total blending amount of (a) component and (b) component; The pressure-sensitive adhesive according to any one of the above [1] to [4], wherein the mass ratio of the component to the compounding amount is ((I) + (B)) / (D) = 10/90 to 90/10 Composition.
[(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 The polymer blocks f, n and m each represent an integer of 1 or more.) The mass ratio of the polymer block e to the polymer block f is e / f = 5. Hydrogenated copolymer obtained by hydrogenating a block copolymer of / 95 to 50/50 so that the hydrogenation rate is 80% or more [polymer block e] The content of vinyl bonds is 30% or less. A polybutadiene block [polymer block f] a polymer block containing a conjugated diene compound unit and a vinyl bond content of 60% or more [7] comprising the following (e) component, and (a) component and ( (B) Total amount of ingredients and (e) ingredients Mass ratio of the ((a) + (b)) / (e) = 10 / 90-90 / 10 in which the above-mentioned [1] to the pressure-sensitive adhesive composition according to any one of [4].
[Component (e)] A block copolymer comprising the following polymer block h, the following polymer block g, and the following polymer block e, wherein the polymer block h, the polymer block g and the polymer block e In the total 100% by mass, the content of the polymer block h 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 obtained by hydrogenating the block copolymer so that the hydrogenation rate is 80% or more [polymer block h] polymer block mainly composed of aromatic alkenyl compound units [polymer block g ] A polymer block comprising 55 to 100% by mass of a conjugated diene compound unit and 45 to 0% by mass of an aromatic alkenyl compound unit, wherein the vinyl bond content in the conjugated diene compound unit is 40% or more. Polymer block e] Polybutadiene block having a vinyl bond content of 30% or less [8] The following (f) component is included, and the total blending amount of (a) component and (b) component; ) Adhesion according to any one of the above [1] to [4], wherein the mass ratio of the component to the blending amount is ((I) + (B)) / (F) = 10/90 to 90/10 Agent composition.
[(F) Component] A block copolymer comprising the following polymer block h and the following polymer block i, wherein the mass ratio of the polymer block h to the polymer block i is h / i = 5/95. A block copolymer having at least two ends of polymer block h and having at least one polymer block i in the middle portion so that the hydrogenation rate is 80% or more. Hydrogenated hydrogenated copolymer [polymer block h] polymer block mainly composed of aromatic alkenyl compound units [polymer block i] conjugated diene compound units 55 to 100% by mass and aromatic alkenyl compound units 45 A polymer block [9] containing a vinyl bond in the conjugated diene compound unit of 60% or more, and a base material layer comprising the polyolefin, and the base material layer It is a surface protection film which consists of an adhesive layer formed by laminating | stacking on one side, Comprising: The said adhesive layer consists of an adhesive composition as described in any one of said [1]-[8]. Surface protective film.
[10] A method for producing a surface protective film according to [9], 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, and therefore, when the adhesive layer-containing member (for example, an optical surface protective film) is peeled from the adherend, problems such as adhesive residue may occur. No peeling work 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 two 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 component (b). 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”.

First, in the pressure-sensitive adhesive composition of the present invention, the component (A) and the component (B) blended as essential components are both block polymers containing the following polymer block a and the following polymer block b as constituent blocks ( This is a hydrogenated copolymer obtained by hydrogenating (pre-hydrogenated copolymer). Here, the polymer block a and the polymer block b constituting the pre-hydrogenation copolymer will be described.
[Polymer block a] Polymer block in which the content of aromatic alkenyl compound units is 70% by mass or more [Polymer block b] The content of conjugated diene compound units is 50% by mass or more, and vinyl bonds derived from conjugated diene compounds Polymer block having a content of 60% or more

[Polymer block a]
The polymer block a is a polymer block mainly composed of aromatic alkenyl compound units.
The content of the aromatic alkenyl compound unit in the polymer block a is 70% by mass or more, preferably 80% by mass or more, more preferably 90% by mass or more. If the content rate of an aromatic alkenyl compound unit is 70 mass% or more, the thermoplasticity of an adhesive composition can be improved and recycling of an adhesive composition becomes easier. As the repeating unit other than the aromatic alkenyl compound unit which may be contained in a range of less than 30% by mass, a repeating unit derived from a compound copolymerizable with the aromatic alkenyl compound, for example, a conjugated diene compound or (meth) Mention may be made of repeating units derived from acrylic ester compounds. Of these, 1,3-butadiene and isoprene are preferred because of their high copolymerizability with aromatic alkenyl compounds.
Examples of the aromatic alkenyl compound that is a monomer constituting the aromatic alkenyl compound unit include styrene, tert-butylstyrene, α-methylstyrene, p-methylstyrene, p-ethylstyrene, divinylbenzene, 1,1. -Diphenylethylene, vinylnaphthalene, vinylanthracene, N, N-diethyl-p-aminoethylstyrene, vinylpyridine and the like are used. Of these, styrene is preferred because the raw materials are easily industrially available.

[Polymer block b]
The polymer block b is a polymer block in which the content of the conjugated diene compound unit is 50% by mass or more and the content of the vinyl bond derived from the conjugated diene compound is 60% or more.

The polymer block b is a polymer block mainly composed of a conjugated diene compound unit. The content rate of a conjugated diene compound unit is 50-100 mass%, Preferably it is 65-100 mass%, More preferably, it is 80-100 mass%, Most preferably, it is 90-100 mass%. By making the content rate of a conjugated diene compound unit into said numerical range, the softness | flexibility of an adhesive composition can be improved.
Examples of the repeating unit other than the conjugated diene compound unit that may be contained in the polymer block b in a range of less than 50% by mass include units derived from an aromatic alkenyl compound and a (meth) acrylic acid ester compound. An aromatic alkenyl compound unit is preferred. Of these, styrene is preferably used.
In the polymer block b, the content of repeating units other than the conjugated diene compound unit is less than 50% by mass, preferably 0 to 35% by mass, more preferably 0 to 20% by mass, and most preferably 0 to 10% by mass. It is.
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 preferably 60%. As mentioned above, More preferably, it is 60 to 90%. 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.

Next, the (a) component and the (b) component, which are hydrogenated copolymers of a block copolymer (copolymer before hydrogenation) including such polymer block a and polymer block b, will be described.
[(I) component]
The component (a) includes the polymer block a and the polymer block b, 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). And a block copolymer having a content of aromatic alkenyl compound units of 5% by mass or more and less than 30% by mass is hydrogenated so that the hydrogenation rate is 80% or more. This is a hydrogenated copolymer.
That is, component (a) is [AB] _n (where A is a polymer block derived from polymer block a, B is a polymer block derived from polymer block b, and n is an integer of 1 to 3). And a content of aromatic alkenyl compound units of 5% by mass or more and less than 30% by mass.
(A) As an example of a component, [A-B] (n = 1), [A-B-A-B] (n = 2), [A-B-A-B-A-B] (n = Examples thereof include a block copolymer having the structure 3). 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 a hydrogenated copolymer used as component (a), a block copolymer having a structure of [AB] (i.e., [ab] is used from the viewpoint of improving industrial productivity and adhesive strength. A block copolymer having a structure of (a hydrogenated copolymer of a copolymer before hydrogenation) is particularly preferred.
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 hydrogenated copolymer needs to have an aromatic alkenyl compound unit content of 5% by mass or more and less than 30% by mass. By setting the content of the aromatic alkenyl compound unit to 5% by mass or more and less than 30% by mass, a pressure-sensitive adhesive composition having an appropriate holding power and followability to the uneven surface of the adherend surface is constituted. It becomes possible. In particular, considering the followability of the surface of the adherend to the uneven surface, the content of the aromatic alkenyl compound unit is preferably 5% by mass or more and less than 25% by mass, and 5 to 20% by mass. Is more preferable, and it is especially preferable to set it as 7-20 mass%.
Further, in the hydrogenated copolymer as the component (a), the mass ratio of the polymer block A and the polymer block B is preferably A / B = 5/95 to 50/50.

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 100,000 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. 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 it difficult to industrially produce the component (a). 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 hydrogenated copolymer has a melt flow rate (MFR) measured at 230 ° C. and a load of 21.2 N of preferably 0.01 to 100 g / 10 minutes, more preferably 0.01 to 80 g / 10 minutes. is there.

[(B) component]
The component (b) includes the polymer block a and the 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. An integer, Y represents a coupling agent residue), and a hydrogenation rate of a block copolymer having an aromatic alkenyl compound unit content of 5% by mass or more and less than 30% by mass is 80%. A hydrogenated copolymer obtained by hydrogenation as described above.
That is, the component (b) is [AB] _x -Y (where A is a polymer block derived from the polymer block a, B is a polymer block derived from the polymer block b, and x is 2 or more. An integer, Y represents a coupling agent residue.), And the content of the aromatic alkenyl compound unit is 5% by mass or more and less than 30% by mass.
As a hydrogenated copolymer having such a structure, for example, a bimolecular coupling body represented by [(AB) -Y- (AB)] (when x = 2), Examples include coupling bodies (so-called star polymers) having 3 or more molecules. However, the production of component (b) 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. In the hydrogenated block copolymer, the polymer blocks A contained in two or more may be different polymer blocks or the same polymer block. The same applies to the polymer block B.
The component (b) can be synthesized with the above-described component (a) in one pot 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.

In the hydrogenated copolymer, the content of the aromatic alkenyl compound unit is required to be 5% by mass or more and less than 30% by mass for the same reason as the component (a), and 5% by mass or more, 25 It is preferably less than mass%, more preferably 5 to 20 mass%.
In the hydrogenated copolymer, the mass ratio of the polymer block A and the polymer block B is preferably A / B = 5/95 to 50/50.

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 (b) 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 (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.

The hydrogenation rate of the hydrogenated copolymer (component (A), component (B)) is 80 to 100%, preferably 90 to 100%, more preferably 95 to 100%. By setting the hydrogenation rate within the above range, a pressure-sensitive adhesive composition having excellent heat resistance can be formed. In this specification, “hydrogenation rate” means a hydrogenation rate calculated from a 270 MHz, ¹ H-NMR spectrum using carbon tetrachloride as a solvent.

Next, in the pressure-sensitive adhesive composition of the present invention, the components (c) to (f) used together with the components (a) and (b) will be described.
[(C) component]
The component (c) is a block copolymer (copolymer before hydrogenation) composed of the following polymer block h, the following polymer block c, and the following polymer block d, and the aromatic alkenyl compound unit / A hydrogenated copolymer obtained by hydrogenating a block copolymer having a conjugated diene compound unit mass ratio of 5/95 to 60/40 so that the hydrogenation rate is 80% or more.
[Polymer block h] Polymer block mainly composed of aromatic alkenyl compound units [Polymer block c] Polymer block consisting only of conjugated diene compound units, or random copolymer of conjugated diene compound units and aromatic alkenyl compound units A polymer block (wherein the content of the aromatic alkenyl 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 alkenyl compound unit, wherein the aromatic alkenyl compound unit is gradually increased. [H-c-d] (where h is polymer block h, c is polymer block c, and d is polymer block d. It has a structure represented by.
The content of the aromatic alkenyl compound unit in the polymer block h is preferably 80% by mass or more, more preferably 90% by mass or more. Examples of the monomer unit other than the aromatic alkenyl compound unit include a conjugated diene compound unit.
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 to the conjugated diene compound unit is aromatic alkenyl 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 (component (C)) obtained by hydrogenating such a pre-hydrogenated copolymer is, for example, [HCD] (where H is a polymer derived from the polymer block h). 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 block f, n and m each independently represents an integer of 1 or more.) A block copolymer (for example, linear or branched) having a structure of This is a hydrogenated copolymer obtained by hydrogenating a block copolymer having a mass ratio with the coalescence block f of e / f = 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 alkenyl 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). A polymer block derived from the combined block e, F represents a polymer block derived from the polymer block f, and n and m each independently represents 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 h (the definition and details of the polymer block h are the same as those of the polymer block h in the above component (c)), the following polymer block g, and the following weight. A block copolymer including a 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 h and the polymer block g In a total of 100% by mass of the polymer block e, the content of the polymer block h 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%. It is a hydrogenated copolymer obtained by hydrogenating a block copolymer having a mass% of such that the hydrogenation rate is 80% or more.
[Polymer block h] Polymer block mainly composed of aromatic alkenyl compound units [Polymer block g] Containing 55 to 100% by mass of conjugated diene compound units and 45 to 0% by mass of aromatic alkenyl compound units, Polymer block in which the content of vinyl bonds in the diene compound unit is 40% or more [Polymer block e] Polybutadiene block in which the content of vinyl bonds is 30% or less A copolymer before hydrogenation of the above component (e) The constituent polymer block g comprises 55-100% by mass of conjugated diene compound units and 45-0% by mass of aromatic alkenyl compound units, and the vinyl bond content in the conjugated diene compound units is 40% or more. It is a coalesced block.
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 alkenyl 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 setting the contents of the conjugated diene compound unit and the aromatic alkenyl compound unit within the above numerical range, the flexibility of the pressure-sensitive 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 h, the polymer block g, and the polymer block e is as follows.
The content rate of the polymer block h 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 obtained by hydrogenating such a pre-hydrogenated copolymer (component (e)) is, for example, [E-G-H] (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 H represents a polymer block derived from the polymer block h.
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) is a block containing the following polymer block h (the definition and details of the polymer block h are the same as those of the polymer block h in the component (c)) and the following polymer block i. A copolymer in which the mass ratio of the polymer block h to the polymer block i is h / i = 5/95 to 45/55, and at least two terminals are the polymer block h, A block copolymer having at least one polymer block i in a portion (excluding a copolymer obtained by coupling is excluded. Hereinafter, a block copolymer before hydrogenation is referred to as a copolymer before hydrogenation. )) Is a hydrogenated copolymer obtained by hydrogenation so that the hydrogenation rate is 80% or more.
[Polymer block h] A polymer block mainly composed of an aromatic alkenyl compound unit [Polymer block i] containing 55 to 100% by mass of a conjugated diene compound unit and 45 to 0% by mass of an aromatic alkenyl compound unit. A polymer block having a vinyl bond content of 60% or more in a diene compound unit.
In the polymer block i, the content of the conjugated diene compound unit is 55 to 100% by mass, preferably 65 to 100% by mass, more preferably 80 to 100% by mass, and most preferably 85 to 100% by mass.
In the polymer block i, the content of the aromatic alkenyl compound unit is 0 to 45% by mass, preferably 0 to 35% by mass, more preferably 0 to 20% by mass, and most preferably 0 to 15% by mass.
By setting the contents of the conjugated diene compound unit and the aromatic alkenyl compound unit within the above numerical range, the flexibility of the pressure-sensitive 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 i, the vinyl bond content is 60% or more, preferably 60 to 90%, more preferably 65 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.
Examples of the copolymer before hydrogenation include [h ₁ -i-h ₂ ], [h ₁ -i ₁ -i ₂ -h ₂ ], [h ₁ -i-h ₂ -h ₃ ], [h ₁ -i ₁ -i ₂ -i ₁ -h ₂ ] (where h ₁ , h ₂ and h ₃ are polymer blocks satisfying the conditions of the polymer block h, and i ₁ and i ₂ are polymer blocks i A polymer block that satisfies the following condition :). In these block copolymers, for example, h ₁ , h ₂ , h ₃ and i ₁ , i ₂ are related to the polymer block h and the polymer block g, and each is a different polymer block (for example, h ₁ , h ₂ and h ₃ may be different from each other) or the same polymer block (for example, h ₁ , h ₂ and h ₃ are all the same).
In the hydrogenated copolymer, the mass ratio of the polymer block h to the polymer block i is h / i = 5/95 to 45/55, preferably 10/90 to 35/65. .

Hydrogenated copolymers obtained by hydrogenating such a pre-hydrogenated copolymer (component (f)) are, for example, [H ₁ -I-H ₂ ], [H ₁ -I ₁ -I _2- H ₂ ], [H ₁ -I-H ₂ -H ₃ ], [H ₁ -I ₁ -I ₂ -I ₁ -H ₂ ] and the like. (However, H ₁ , H ₂ , and H ₃ are polymer blocks derived from the polymer block h, and I ₁ and I ₂ are polymer blocks derived from the polymer block i.). In these block copolymers, for example, H ₁ , H ₂ , H ₃ and I ₁ , I ₂ are related to the polymer blocks H, I, and each is a different polymer block (eg, H ₁ , H ₂ , H ₃ may be all different) or the same polymer block (for example, H ₁ , H ₂ and H ₃ are all the same).
The terminal polymer block H preferably accounts for 2% by mass or more of the entire copolymer. This is because the effect of the polymer block H is reliably 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 (aggregation of two or more kinds of copolymers) constituting the pressure-sensitive adhesive composition of the present invention contains (a) component and (b) component as essential components.
In the copolymer composition, the total amount of the component (a) and the component (b) is 100% by mass, and the amount of the component (b) is 70% by mass or more, more preferably 75% by mass or more, particularly preferably. 80% by mass or more. (B) When the blending ratio of the component is 70% by mass or more, an effect excellent in suppressing the adhesion progress can be exhibited.
Further, the content is preferably 95% by mass or less, more preferably 90% by mass or less, from the viewpoint of maintaining adhesive strength and fluidity (film forming property of the adhesive layer).
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 (a) and the component (b) and the blending amount of the component (f) is ((b) + (b)) / (e) = 10/90 to 90/10, preferably 30/70 to 90/10, more preferably 50/50 to 90/10.

  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 alkenyl 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 conditions such as the content ratio of the aromatic alkenyl compound unit, the vinyl bond content of the conjugated diene compound unit contained in the component (b) and the 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, 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.) depends on the conditions such as the content of aromatic alkenyl compound units, the vinyl bond content of the conjugated diene compound units contained in component (a) and component (b), and the hydrogenation rate. Can be controlled.
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.

  Further, as other examples of optional components that can be blended with the copolymer composition, the pressure-sensitive adhesive composition of the present invention includes a polyolefin resin, an antioxidant, an ultraviolet absorber, a colorant, a light stabilizer, a heat stabilizer, Examples thereof include a polymerization inhibitor, an antifoaming agent, a leveling agent, an antistatic agent, a surfactant, a storage stabilizer, and a filler.

  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 0.35 N / 10 mm or less, preferably 0.33 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. Moreover, this test piece is left to stand in a 40 degreeC atmosphere for 7 days, and 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.

[2] Manufacturing method As a manufacturing method of 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 as necessary. A method of mixing arbitrary components such as the above-mentioned components (c) to (f) is preferred. 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 the structure of [ab] (a copolymer before component (i) before hydrogenation) by 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 (copolymer before hydrogenation of component (b)), and a third step: Hydrogenation of the copolymer having the structure [AB] _x- Y by hydrogenating the copolymer having the structure [ab] _x -Y (component (A)) and prepared _{{[a-B] x -Y} } hydrogenated copolymer having a structure of ((b) component), it 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 (for example, in the case of component (c), polymer block h, polymer block c, and polymer block d) constituting the pre-hydrogenated copolymer. 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.

[3] 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 the resin composition for the base material made of synthetic resin and the pressure-sensitive adhesive composition by coextrusion, for example, 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 (for example, a surface protective film for an optical film).

  Hereinafter, the pressure-sensitive adhesive composition and pressure-sensitive adhesive body of the present invention will be described more specifically with reference to examples. However, these examples merely show some embodiments of the present invention. Accordingly, the present invention should not be construed as being 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., 90 parts by mass of 1,3-butadiene was added, and temperature-initiated polymerization was further performed.
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. Copolymer composition 1 includes a copolymer (A-1) having a structure of [AB] as (A) component, and [AB] _2- Y (Y is a coupling) as (B) component. And a copolymer (B-1) having a structure of (agent residue).

(Copolymer composition 2, 5, 6)
The structure of [AB] is the same as that of the copolymer composition 1 except that the amount of the monomer (styrene, 1,3-butadiene), coupling agent, catalyst, and the like is appropriately adjusted. Copolymer (b-1) ((b)) having a structure of copolymer (b-1) (component (b)) and [AB] _2- Y (Y is a coupling agent residue) Copolymer compositions 2, 5 and 6 comprising
(Copolymer composition 3, 4, 7, 8)
The structure of [AB] is the same as that of the copolymer composition 1 except that the amount of the monomer (styrene, 1,3-butadiene), coupling agent, catalyst, and the like is appropriately adjusted. Copolymer (b-2) (component (b)) and copolymer having a structure of [AB] ₂ -Y (Y is a coupling agent residue) (b-2) ((b) Copolymer compositions 3, 4, 7, and 8 were obtained.
Table 1 shows the physical properties of the copolymers (I-1), (I-2), copolymers (B-1), and (B-2) constituting the obtained copolymer compositions 1-8. .

(Copolymer composition 9)
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. When the absorption of hydrogen is completed, the reaction solution is returned to room temperature and normal pressure, and is taken out of the reaction vessel to obtain a [HIH] structure. The copolymer composition 9 which consists of a copolymer (he-1) which has this was obtained.
Table 1 shows the physical properties of the copolymer (F-1).

(Copolymer composition 10-12)
A composition 10 comprising the copolymer (C-1) in the same manner as the copolymer composition 9 except that the blending amount of the monomer (styrene, 1,3-butadiene), catalyst, etc. was appropriately adjusted. Each of the composition 11 consisting of a copolymer (d-1) and the composition 12 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 each block The mass ratio of each block was calculated | required from the preparation amount of the raw material when manufacturing a copolymer. (For example, the mass ratio of the polymer block A and the polymer block B was calculated.
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, i-2, ro-1, ro-2)," (mass of copolymer block H)-(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 G)-(mass of copolymer block H) "(e-1)," (mass of copolymer block H)-(copolymer block) (Mass of I)-(mass of copolymer block H) "(f-1).
(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)
Carbon tetrachloride was used as a solvent, and calculation was performed from a 270 MHz, ¹ H-NMR spectrum.
(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. Further, the test piece was left in a 40 ° C. atmosphere for 7 days, and then a peel test was performed again to obtain an increase value relative to the initial strength.
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 2-4, Comparative Examples 1-4)
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.

(Examples 5 and 6)
Copolymer composition 3 (composition consisting of copolymer (b-2) and copolymer (b-2)) and copolymer composition 10 (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 7)
Copolymer composition 3 (composition consisting of copolymer (b-2) and copolymer (b-2)) and copolymer composition 11 (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 8)
Mixture of copolymer composition 3 (composition comprising copolymer (ii-2) and copolymer (ro-2)) and composition 12 (composition comprising 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 9
Mixture of copolymer composition 3 (composition consisting of copolymer (b-2) and copolymer (b-2)) and composition 9 (composition consisting of 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 5 to 8)
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 a large increase in adhesive strength.

Claims (10)

A pressure-sensitive adhesive composition comprising the following component (a) and the following component (b), wherein the compounding amount of component (b) is 70% by mass or more in a total amount of 100% by mass of component (b) and component (b). A pressure-sensitive adhesive composition having a peel strength increase value (left at 40 ° C. for 7 days) of 0.35 N / 10 mm or less.
[Component (a)] 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). And a block copolymer having a content of aromatic alkenyl compound units of 5% by mass or more and less than 30% by mass is hydrogenated so that the hydrogenation rate is 80% or more. The hydrogenated copolymer [(B) component] comprises the following polymer block a and the following polymer block b, [ab] _x -Y (where a is the polymer block a and b is the polymer block b) , X represents an integer of 2 or more, and Y represents a coupling agent residue.) And a block copolymer having an aromatic alkenyl compound unit content of 5% by mass or more and less than 30% by mass. Hydrogenated co-polymerized by hydrogenation so that the hydrogenation rate is 80% or more Polymer [polymer block a] Polymer block having a content of aromatic alkenyl compound units of 70% by mass or more [Polymer block b] Content of conjugated diene compound units of 50% by mass or more, vinyl bond derived from conjugated diene compound Polymer block having a content of 60% or more   The pressure-sensitive adhesive composition according to claim 1, wherein the content of the aromatic alkenyl compound unit in each of the component (a) and the component (b) is 5% by mass or more and less than 25% by mass.   In each of the component (a) and component (b), the polymer block a contains a styrene unit as an aromatic alkenyl compound unit, and the polymer block b contains 1,3- The pressure-sensitive adhesive composition according to claim 1 or 2, comprising a butadiene unit and / or an isoprene unit.   The component (a) is composed of the polymer block a and the polymer block b, and has a structure [ab] (wherein a represents the polymer block a and b represents the polymer block b). The pressure-sensitive adhesive composition according to any one of claims 1 to 3, comprising a hydrogenated copolymer. The following (c) component is included, and the mass ratio of the total blending amount of the (b) component and the (b) component to the blending amount of the (c) component is ((b) + (b)) / ( C) It is 10 / 90-90 / 10, The adhesive composition of any one of Claims 1-4.
[Component (c)] A block copolymer comprising the following polymer block h, the following polymer block c, and the following polymer block d, wherein the mass ratio of the aromatic alkenyl compound unit / conjugated diene compound unit is Hydrogenated copolymer obtained by hydrogenating a block copolymer of 5/95 to 60/40 so that the hydrogenation rate is 80% or more [polymer block h] mainly comprising an aromatic alkenyl compound unit. Polymer block [polymer block c] Homopolymer block of conjugated diene compound or random copolymer block of conjugated diene compound and aromatic alkenyl compound (however, the content of aromatic alkenyl compound unit is 45% by mass) And a polymer block [polymer block d] conjugated diene compound unit and an aromatic compound having a vinyl bond content of 60% or more. And a Kenyir compound units, tapered block aromatic vinyl compound units increases gradually 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 to 90/10. The pressure-sensitive adhesive composition according to any one of claims 1 to 4.
[(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 The polymer blocks f, n and m each represent an integer of 1 or more.) The mass ratio of the polymer block e to the polymer block f is e / f = 5. Hydrogenated copolymer obtained by hydrogenating a block copolymer of / 95 to 50/50 so that the hydrogenation rate is 80% or more [polymer block e] The content of vinyl bonds is 30% or less. A polybutadiene block [polymer block f] a polymer block containing a conjugated diene compound unit and having a vinyl bond content of 60% 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 ((I) + (B)) / ( E) = 10/90 to 90/10. The pressure-sensitive adhesive composition according to any one of claims 1 to 4.
[Component (e)] A block copolymer comprising the following polymer block h, the following polymer block g, and the following polymer block e, wherein the polymer block h, the polymer block g and the polymer block e In the total 100% by mass, the content of the polymer block h 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 obtained by hydrogenating the block copolymer so that the hydrogenation rate is 80% or more [polymer block h] polymer block mainly composed of aromatic alkenyl compound units [polymer block g ] A polymer block comprising 55 to 100% by mass of a conjugated diene compound unit and 45 to 0% by mass of an aromatic alkenyl compound unit, wherein the vinyl bond content in the conjugated diene compound unit is 40% or more. Polybutadiene block polymer block e] content of vinyl bond is 30% or less 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 any one of claims 1 to 4.
[(F) Component] A block copolymer comprising the following polymer block h and the following polymer block i, wherein the mass ratio of the polymer block h to the polymer block i is h / i = 5/95. A block copolymer having at least two ends of polymer block h and having at least one polymer block i in the middle portion so that the hydrogenation rate is 80% or more. Hydrogenated hydrogenated copolymer [polymer block h] polymer block mainly composed of aromatic alkenyl compound units [polymer block i] conjugated diene compound units 55 to 100% by mass and aromatic alkenyl compound units 45 A polymer block having a vinyl bond content in the conjugated diene compound unit of 60% 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 1-8. 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 9, 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.