JP6069004B2 - Adhesive composition and surface protective film - Google Patents

Description

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

  Conventionally, rubber-based pressure-sensitive adhesives mainly composed of rubbers such as acrylic pressure-sensitive adhesives, natural rubbers, and polyisobutylenes are mainly used as pressure-sensitive adhesives used for the surface protective film pressure-sensitive adhesive layer.

  As a method of applying these pressure-sensitive adhesives to a predetermined support film, a method of applying a pressure-sensitive adhesive solution obtained by dissolving a pressure-sensitive adhesive in a solvent using a roll, a spray or the like is used. These methods have the advantage that the pressure-sensitive adhesive layer can be applied uniformly and thinly, but the use of a solvent is from the viewpoint of air pollution, fire, safety and hygiene during production, economics, etc. It is not preferable.

  On the other hand, as a technology for producing a hot-melt type surface protection film that does not use a solvent, a technology for producing a laminate of a pressure-sensitive adhesive layer and a support film by co-extrusion is known. A melt-type pressure-sensitive adhesive has been developed (see, for example, Patent Document 1).

  In addition, as an adhesive having excellent adhesive strength, it consists of a block mainly composed of a vinyl aromatic compound and a block mainly composed of a conjugated diene, and a part of the double bond of the conjugated diene part is hydrogenated and the rest An adhesive composition comprising an epoxy-modified hydrogenated block copolymer obtained by epoxidizing a part of the double bond has been proposed (see, for example, Patent Document 2).

  Further, when an olefin resin film, which is a representative of a difficult-to-adhere material, is used as a support film, a copolymer having a high affinity with the olefin resin film and having ethylene as a main component, such as ethylene vinyl acetate (EVA). ) Has been proposed (see, for example, Patent Document 3).

  In addition, a surface protective sheet made of a polyolefin resin for the base material layer, a propylene copolymer and a hydrogenated styrene thermoplastic elastomer for the adhesive layer, and formed by coextrusion (see, for example, Patent Document 4) ) And pressure-sensitive adhesive layers have been proposed protective films comprising a block copolymer containing a poly (monovinyl aromatic hydrocarbon) block and a hydrogenated poly (conjugated) diene block and a tackifying resin (for example, Patent Document 5). reference).

JP 2003-327936 A JP-A-8-73699 JP-A-61-103975 JP 2004-2624 A Special table 2009-520042

  Surface protective film is polarizing plate, retardation film, light guide plate, optical film for LCD, sheet, touch panel substrate film, antireflection film for PDP, optical protective film used for surface protection of optical members, steel plate for automobiles, etc. It is used in a wide variety of fields such as protective films and protective films of various plastics, and adhesiveness and adhesive strength are required depending on the application. For example, if the adhesive force is too high, a large force is required for peeling off, which may cause a problem that workability is inferior. On the other hand, if the adhesive force is too low, there may be a problem that the adhesive peels off during storage. Therefore, it is preferable from the viewpoint of workability to have adhesiveness and adhesive strength according to the application.

  In general, the common performance required for the surface protective film is that the adhesive force and the adhesiveness do not change even when stored for a long time or under a low temperature. Such a surface protective film is excellent in workability. In addition, it is an important required performance that no adhesive remains on the adherend when the attached surface protective film is peeled off.

  However, as in Patent Document 1, it is difficult to perform corona treatment, alkali treatment, flame treatment, etc. on the surface of the support film in the technique for producing a laminate of the pressure-sensitive adhesive layer and the support film by coextrusion. Therefore, there is a problem that it is difficult to obtain a coextruded film having a strong adhesive force between the support and the pressure-sensitive adhesive layer. Specifically, when the laminate of the support film and the pressure-sensitive adhesive layer is attached to a metal plate or the like and peeled off, interfacial peeling occurs between the support film and the pressure-sensitive adhesive layer, resulting in adhesive residue. There is a problem that it is easy.

  Moreover, the adhesive composition disclosed in Patent Document 2 is severely gelled or deteriorated by heating or long-term storage, and has a problem to be solved regarding long-term stability.

  Furthermore, the coextruded film disclosed in Patent Document 3 has a problem that sufficient adhesiveness cannot be obtained. In particular, for those having a very low vinyl acetate content, the decrease in tackiness is significant.

  Furthermore, in the above-mentioned Patent Document 3, for example, an adhesive layer using an ABA (A is a styrene polymer block and B is an ethylene / butylene copolymer block) block copolymer is described as an olefin resin. An adhesive film for surface protection formed on a film is disclosed. However, this pressure-sensitive adhesive layer has a problem that good adhesion cannot be obtained when the adherend is distorted or has a complicated shape. On the other hand, when affixed to a smooth adherend, there is a problem that the adhesive strength changes due to storage for a long period of time and adhesive residue is generated when the film is peeled off.

  Furthermore, the surface protective sheet and the protective film disclosed in Patent Document 4 and Patent Document 5 also have a property balance such as adhesiveness at each temperature, adhesive strength, and adhesion progress of adhesive strength (improvement of adhesive strength over time). In view of this, further improvements are desired.

  Therefore, the present invention has been made in view of the above problems, and by adjusting the formulation, it can exhibit appropriate adhesive strength and adhesiveness for each application, has excellent coating properties, and takes a long time. Adhesive composition that maintains its adhesiveness and adhesive strength, has excellent adhesiveness and adhesiveness under both low temperature conditions and room temperature conditions, and has little adhesive residue, and adhesion containing the adhesive composition It aims at providing the surface protection film which has an agent layer.

As a result of intensive studies to solve the above problems, the present inventors have found that the content of the polymer block mainly composed of vinyl aromatic monomer units, 1, 1 of conjugated diene monomer units before hydrogenation. Total amount of 2 bonds and 3,4 bonds, hydrogenation rate of conjugated diene moiety, melt flow rate value of block copolymer (hereinafter referred to as “MFR”) and order-disorder transition temperature of block copolymer By using a block copolymer having a specific range (hereinafter referred to as “ODT”), it has been found that the above problems can be solved, and the present invention has been completed.
That is, the present invention is as follows.
[1]
A pressure-sensitive adhesive composition comprising a block copolymer having a polymer block A mainly composed of vinyl aromatic monomer units and a polymer block B mainly composed of conjugated diene monomer units,
The block copolymer satisfies the following conditions (1) to (5):
Adhesive composition.
(1) The total content of 1,2-bond amount and 3,4-bond amount in the conjugated diene monomer unit is 65 to 90%.
(2) The content of the vinyl aromatic monomer unit is 12 to 25% by mass.
(3) The hydrogenation rate of the double bond derived from the conjugated diene monomer unit of the polymer block B is 90% or more. (4) The melt flow rate value (MFR) of the block copolymer is 15 to 60 g. / 10 minutes (5) The order-disorder transition temperature (ODT) of the block copolymer is 160 to 210 ° C.
[2]
The block copolymer has two or more polymer blocks A and two or more polymer blocks B;
There is the polymer block B at at least one end of the block copolymer,
The pressure-sensitive adhesive composition according to [1], wherein the content of the polymer block B at at least one terminal of the block copolymer is 0.5 to 9% by mass.
[3]
The block copolymer has two polymer blocks A1 and A2 and two polymer blocks B1 and B2.
The block copolymer has a structure represented by A1-B1-A2-B2,
The pressure-sensitive adhesive composition according to [1] or [2], wherein a mass ratio (B2 / B1) between the polymer block B1 and the polymer block B2 is 0.10 or less.
[4]
For 100 parts by mass of the block copolymer,
The pressure-sensitive adhesive composition according to any one of [1] to [3], further containing 10 to 100 parts by mass of a tackifier.
[5]
For 100 parts by mass of the block copolymer,
The pressure-sensitive adhesive composition according to any one of [1] to [4], further containing 10 to 100 parts by mass of a polyolefin-based resin.
[6]
For 100 parts by mass of the block copolymer,
The pressure-sensitive adhesive composition according to any one of [1] to [5], further containing 10 to 100 parts by mass of a hydrogenated styrene elastomer.
[7]
A base film;
The surface protection film which has an adhesive layer containing the adhesive composition of any one of said [1]-[6] on this base film.

  According to the present invention, moderate adhesive strength and adhesiveness can be exhibited for each application, excellent coating properties, adhesiveness and adhesive strength are maintained for a long time, under low temperature conditions and room temperature conditions. In any case, a pressure-sensitive adhesive composition having excellent adhesiveness and adhesive strength and little adhesive residue, and a surface protective film having an adhesive layer containing the pressure-sensitive adhesive composition are obtained.

  Hereinafter, a mode for carrying out the present invention (hereinafter referred to as “the present embodiment”) will be described in detail. In addition, this invention is not restrict | limited to the following embodiment, A various deformation | transformation can be implemented within the range of the summary.

[Adhesive composition]
The pressure-sensitive adhesive composition according to this embodiment is a block copolymer having a polymer block A mainly composed of vinyl aromatic monomer units and a polymer block B mainly composed of conjugated diene monomer units. ,including.

[Block copolymer]
The block copolymer used in the present embodiment is a block copolymer having a polymer block A and a polymer block B, and satisfies the following conditions (1) to (5).
(1) The total content of 1,2-bond amount and 3,4-bond amount in the conjugated diene monomer unit is 65 to 90%.
(2) Content of vinyl aromatic monomer unit is 12 to 25% by mass
(3) Hydrogenation rate of double bond derived from conjugated diene monomer unit of polymer block B is 90% or more (4) MFR of block copolymer is 15 to 60 g / 10 minutes (5) Block copolymer Combined ODT is 160-210 ° C

  In addition, in this embodiment, the naming of each monomer unit which comprises a block copolymer shall follow the naming of the monomer from which the said monomer unit derives. For example, “vinyl aromatic monomer unit” means a structural unit of a polymer produced as a result of polymerizing a vinyl aromatic compound as a monomer. The structure is a molecular structure in which two carbons of a substituted ethylene group derived from a substituted vinyl group are binding sites.

  The “conjugated diene monomer unit” means a structural unit of a polymer produced as a result of polymerizing a conjugated diene compound as a monomer. The structure is a molecular structure in which two carbons of an olefin derived from a conjugated diene monomer are binding sites.

  In the present embodiment, “mainly” means that one polymer block contains 60% by mass or more of the target monomer unit. It is preferable to contain 80% by mass or more of monomer units, more preferably 90% by mass or more, and even more preferably 95% by mass or more. For example, the polymer block A mainly composed of vinyl aromatic monomer units contains 60% by mass or more of vinyl aromatic monomer units in the polymer block A.

  The “vinyl aromatic monomer” is not particularly limited, but examples thereof include styrene, α-methylstyrene, p-methylstyrene, divinylbenzene, 1,1-diphenylethylene, N, N-dimethyl-p-amino. Examples thereof include vinyl aromatic compounds such as ethylstyrene and N, N-diethyl-p-aminoethylstyrene. These may be used alone or in combination of two or more. Among these, it is preferable to use styrene from the viewpoint of adhesive strength and supply stability.

  The “conjugated diene monomer” is a diolefin having a pair of conjugated double bonds and is not particularly limited. For example, 1,3-butadiene, 2-methyl-1,3-butadiene (isoprene), Examples include 2,3-dimethyl-1,3-butadiene, 1,3-pentadiene, 2-methyl-1,3-pentadiene, 1,3-hexadiene, and the like. In particular, 1,3-butadiene and isoprene are preferable. These may be used alone or in combination of two or more. In the pressure-sensitive adhesive composition of this embodiment, 1,3-butadiene and isoprene are more preferably mainly composed of 1,3-butadiene from the viewpoint of obtaining high mechanical strength. When two or more kinds of conjugated diene monomers are used in combination, the 1,3-butadiene content relative to the total amount of conjugated diene monomers in the polymer block mainly composed of one conjugated diene monomer unit is 80. It is preferably at least mass%, more preferably at least 90 mass%, and even more preferably at least 95 mass%.

(1) Total content of 1,2-bond amount and 3,4-bond amount in the conjugated diene monomer unit The microstructure of the conjugated diene monomer unit constituting the block copolymer used in this embodiment is The total content of 1,2-bond amount and 3,4-bond amount is 65 to 90%, preferably 68 to 90%, based on the total amount of conjugated diene monomer units in the block copolymer. 72-88% is more preferable. When the total content is 65% or more, even after pasting for a long period of time, it has an appropriate adhesive force, and adhesive residue is less likely to occur when the film is peeled off. Moreover, the adhesive force of the obtained adhesive composition improves more because the said total content is 90% or less. The 1,2-bond amount and 3,4-bond amount can be determined by measuring the block copolymer before hydrogenation using a nuclear magnetic resonance spectrum analysis (NMR) as a sample. Can be determined by the method described in the Examples.

  The microstructure of the conjugated diene monomer unit can be analyzed by an infrared spectrophotometer (IR), a nuclear magnetic resonance apparatus (NMR), or the like. The total content of the 1,2-bond amount and the 3,4-bond amount can be measured by the method shown in Examples described later.

  Moreover, the vinyl bond amount (total content of 1,2-bond amount and 3,4-bond amount) of the block copolymer is adjusted by adding a polar compound to be described later to produce a block copolymer. can do.

(2) Content of vinyl aromatic monomer unit The content of the vinyl aromatic monomer unit relative to the mass of the block copolymer of the block copolymer used in the present embodiment is 12 to 25% by mass. The range is preferably 13 to 23% by mass, and more preferably 14 to 20% by mass. When the content is 25% by mass or less, the adhesiveness of the adhesive composition is further improved. In addition, when the content is 12% by mass or more, even if the film is stored for a long time after being attached, the adhesiveness and adhesive strength do not become too high, and an adhesive residue is less likely to occur when the film is peeled off.

  Content of a vinyl aromatic monomer unit can be measured by the method described in the Example mentioned later.

  Moreover, content of a vinyl aromatic monomer unit can be adjusted by controlling the addition amount of the vinyl aromatic monomer used when superposing | polymerizing a block copolymer.

(3) Hydrogenation rate of the double bond derived from the conjugated diene monomer unit of the polymer block B The hydrogenation rate of the double bond derived from the conjugated diene monomer of the polymer block B of this embodiment is It is 90% or more with respect to the total amount of the conjugated diene monomer in a block copolymer, 93% or more is preferable and 95% or more is more preferable. Further, the higher the hydrogenation rate, the more preferable, and more preferably 100% or less. When the hydrogenation rate is 90% or more, sufficient adhesive strength can be obtained, crosslinking during extrusion film formation can be prevented, and generation of gel-like substances can be suppressed. The hydrogenation rate can be controlled by the amount of hydrogenation catalyst described later. Moreover, a hydrogenation rate can be measured by the method described in the Example mentioned later.

(4) MFR of block copolymer
The MFR of the block copolymer used in the present embodiment is in the range of 15-60 g / 10 minutes and in the range of 17-55 g / 10 minutes when the measurement conditions are temperature: 230 ° C. and load: 2.16 kg. It is preferably in the range of 20 to 50 g / 10 minutes, more preferably in the range of 25 to 45 g / 10 minutes. When the MFR is 15 g / 10 min or more, the melt viscosity of the pressure-sensitive adhesive composition of the present embodiment, which will be described later, does not increase, and the extrusion film formability becomes better. By being 60 g / 10 min or less, it has higher adhesive force. Thereby, the surface protection film using the pressure-sensitive adhesive composition of the present embodiment hardly causes adhesive residue when the surface protection film is peeled off. The MFR can be controlled by controlling the amount of the lithium initiator, and can be within the above range. In addition, MFR can be measured by the method shown in the Example mentioned later.

(5) ODT of block copolymer
The ODT of the block copolymer used in the present embodiment is in the range of 160 to 210 ° C, preferably in the range of 175 to 205 ° C, and more preferably in the range of 180 to 200 ° C. When the ODT is in the above range, the productivity and the extrusion film forming property become better. ODT can be controlled by controlling the polymer structure, the amount of vinyl aromatic monomer units, the molecular weight, and the like, and can be within the above range. In addition, ODT can be measured by the method shown in the Example mentioned later.

  The block copolymer used in the present embodiment is composed of two or more polymer blocks A (hereinafter also referred to as “A1, A2”, etc.) and two or more polymer blocks B (hereinafter, “ It may be expressed as “B1, B2”, etc.). The number of polymer blocks A is preferably 3 or less, and the number of polymer blocks B is preferably 3 or less. By being such a block copolymer, it tends to be more excellent in adhesive strength.

  Moreover, it is preferable that the polymer block B exists in the at least 1 terminal of a block copolymer. A polymer block mainly composed of a conjugated diene monomer unit has an effect of developing adhesiveness, and since this polymer block is at the end of the block copolymer, it tends to be more excellent in adhesiveness. Furthermore, the content of the polymer block B at at least one terminal of the block copolymer is preferably in the range of 0.5 to 9% by mass relative to the total mass of the block copolymer, The range is more preferably 7% by mass, and further preferably 2-6% by mass. When the content of the polymer block B at at least one terminal is 0.5% by mass or more, the tackiness of the pressure-sensitive adhesive composition tends to be further improved. Moreover, when the content is 9% by mass or less, the cohesive force of the block copolymer is further improved, and the adhesive force of the pressure-sensitive adhesive composition tends to be further improved.

  The content of the polymer block B can be controlled by controlling the monomer feed amount. The content of the polymer block B can be measured by nuclear magnetic resonance spectrum analysis (NMR).

  The block copolymer used in this embodiment has two polymer blocks A1 and A2 and two polymer blocks B1 and B2, and has a structure represented by A1-B1-A2-B2. It is preferable. The mass ratio (B2 / B1) between the polymer block B1 and the polymer block B2 is preferably in the range of 0.10 or less, more preferably in the range of 0.02 to 0.09. More preferably, it is in the range of 0.03 to 0.08. When the mass ratio (B2 / B1) is 0.10 or less, the adhesive strength is further improved and the adhesiveness tends to be moderate.

  The mass ratio (A1 / A2) between the polymer block A1 and the polymer block A2 is preferably in the range of 0.7 to 1.3, and preferably in the range of 0.8 to 1.2. More preferably, it is in the range of 0.9 to 1.1, more preferably in the range of 0.95 to 1.05. When the mass ratio is in the above range, the cohesive force of the block copolymer becomes higher and the adhesive force tends to be more excellent.

  The weight average molecular weight of the block copolymer used in the present embodiment is preferably 40,000 to 200,000, more preferably 50,000 to 170,000, and 60,000 to 150,000. More preferably it is. The molecular weight distribution of a single peak measured by gel permeation chromatography (hereinafter also referred to as “GPC”) is preferably 1.2 or less, more preferably 1.15 or less, and still more preferably. Is 1.1 or less, more preferably 1.08 or less. A weight average molecular weight and molecular weight distribution can be measured by the method shown in the Example mentioned later.

[Method for producing block copolymer]
The method for polymerizing the block copolymer used in the present embodiment is not particularly limited, and examples thereof include coordination polymerization, anionic polymerization, and cationic polymerization. Among these, anionic polymerization is preferable from the viewpoint of easy control of the structure.

  It does not specifically limit as a manufacturing method of the block copolymer by anionic polymerization, A well-known method is applicable. For example, Japanese Patent Publication No. 36-19286, Japanese Patent Publication No. 43-17879, Japanese Patent Publication No. 46-32415, Japanese Patent Publication No. 49-36957, Japanese Patent Publication No. 48-2423, Japanese Patent Publication No. 48-4106, Examples thereof include the methods described in JP-B-56-28925, JP-A-59-166518, JP-A-60-186777, and the like.

  In this embodiment, the block copolymer before hydrogenation can be produced by anionic living polymerization using a lithium initiator in a hydrocarbon solvent. Although it does not specifically limit as a hydrocarbon solvent, Specifically, aliphatic hydrocarbons, such as n-butane, isobutane, n-pentane, n-hexane, n-heptane, n-octane; cyclohexane, cycloheptane, And alicyclic hydrocarbons such as methylcycloheptane; or aromatic hydrocarbons such as benzene, toluene, xylene and ethylbenzene.

  Moreover, it does not specifically limit as a lithium initiator, Specifically, a C1-C20 aliphatic and aromatic hydrocarbon lithium compound is mentioned. The lithium compound includes a compound containing one lithium in one molecule, a dilithium compound, a trilithium compound, and a tetralithium compound containing a plurality of lithiums in one molecule. Specifically, n-propyllithium, n-butyllithium, sec-butyllithium, tert-butyllithium, n-pentyllithium, n-hexyllithium, benzyllithium, phenyllithium, tolyllithium, diisopropenylbenzene and sec -Reaction product of -butyllithium, reaction product of divinylbenzene, sec-butyllithium and a small amount of 1,3-butadiene, and the like. Among these, n-butyllithium and sec-butyllithium are preferable from the viewpoint of polymerization activity.

  Although the addition amount of a lithium initiator is based on the molecular weight of the target block copolymer, generally 0.01-0.5 phm (mass part with respect to 100 mass parts of monomers) can be used. The addition amount of the lithium initiator is preferably 0.03 to 0.3 phm, and more preferably 0.05 to 0.15 phm.

In this embodiment, a tertiary amine compound can be added as a polar compound when block copolymerizing a conjugated diene monomer and a vinyl aromatic monomer using a lithium initiator as a polymerization initiator. Although it does not specifically limit as a tertiary amine compound, Specifically, the compound shown by a following formula is mentioned.
R ¹ R ² R ³ N
(In the formula, R ¹ , R ² , and R ³ are each a hydrocarbon group having 1 to 20 carbon atoms or a tertiary amino group.)

  Such a compound is not particularly limited, and specifically, trimethylamine, triethylamine, tributylamine, N, N-dimethylaniline, N-ethylpiperidine, N-methylpyrrolidine, N, N, N ′, N ′. Tetramethylethylenediamine, N, N, N ′, N′-tetraethylethylenediamine, 1,2-dipiperidinoethane, trimethylaminoethylpiperazine, N, N, N ′, N ″, N ″ -pentamethyl And ethylenetriamine, N, N′-dioctyl-p-phenylenediamine, and the like. Among these, N, N, N ′, N′-tetramethylethylenediamine is preferable.

  The tertiary amine compound can be used to increase the amount of vinyl bonds in the polymer block B. The addition amount can be adjusted by the vinyl bond amount (total of 1,2-bond amount and 3,4-bond amount) of the target conjugated diene part. The vinyl bond amount in the conjugated diene monomer unit of this embodiment is 65 to 90%, and the addition amount of the tertiary amine compound relative to this is preferably 0.1 to 4 (with respect to the lithium initiator). mol / Li), more preferably 0.2 to 3 (mol / Li). However, the addition amount of the tertiary amine compound is not limited to this.

In the present embodiment, sodium alkoxide may coexist during the copolymerization. The sodium alkoxide to be used is not particularly limited, and specific examples thereof include compounds represented by the following formula. Among these, sodium alkoxide having an alkyl group having 3 to 6 carbon atoms is preferable, and sodium t-butoxide and sodium t-pentoxide are more preferable.
NaOR
(In the formula, R is an alkyl group having 2 to 12 carbon atoms.)

  The amount of sodium alkoxide used in the present embodiment is preferably 0.01 or more and less than 0.1 (molar ratio), more preferably 0.01 or more and less than 0.08, relative to the tertiary amine compound. Molar ratio), more preferably 0.03 or more and less than 0.08 (molar ratio), even more preferably 0.04 or more and less than 0.06 (molar ratio). By having the amount of sodium alkoxide within the above range, the polymer block B has a high vinyl bond amount, the polymer block A has a narrow molecular weight distribution, and the copolymer has a narrow molecular weight distribution and a high strength block. The copolymer tends to be obtained at a higher production rate.

  In the present embodiment, the block copolymerization method of a conjugated diene monomer and a vinyl aromatic monomer using a lithium initiator as a polymerization initiator may be batch polymerization, continuous polymerization, or a combination thereof. It may be. In particular, a batch polymerization method is recommended to obtain a block copolymer having a narrow molecular weight distribution and high strength. The polymerization temperature is generally 0 ° C to 150 ° C, preferably 30 ° C to 120 ° C, more preferably 40 ° C to 100 ° C. The time required for polymerization varies depending on the conditions, but is usually within 24 hours, preferably 0.1 to 10 hours. The polymerization atmosphere is preferably an inert gas atmosphere such as nitrogen gas. The polymerization pressure is not particularly limited as long as it is in a range sufficient to maintain the monomer and solvent in a liquid phase within the above polymerization temperature range. Furthermore, it is preferable to take care not to mix impurities such as water, oxygen, carbon dioxide gas, etc. that inactivate the initiator and living polymer into the polymerization system.

  Examples of the method for hydrogenating the conjugated diene portion of the block copolymer used in the present embodiment include a method in which hydrogen is supplied in the presence of a hydrogenation catalyst and the unsaturated portion is hydrogenated. Increasing the amount of catalyst used for hydrogenation can increase the hydrogenation rate.

  The hydrogenation catalyst is not particularly limited, but is a conventionally known hydrogenation catalyst, a supported heterogeneous system in which a metal such as Ni, Pt, Pd, or Ru is supported on carbon, silica, alumina, diatomaceous earth, or the like. Hydrogenation catalyst; so-called Ziegler type hydrogenation catalyst using organic acid salt such as Ni, Co, Fe, Cr or transition metal salt such as acetylacetone salt and reducing agent such as organoaluminum; Ti, Ru, Rh, Zr, etc. And homogeneous hydrogenation catalysts such as so-called organometallic complexes such as organometallic compounds.

  Specific examples of such a hydrogenation catalyst include Japanese Patent Publication No. 42-8704, Japanese Patent Publication No. 43-6636, Japanese Patent Publication No. 63-4841, Japanese Patent Publication No. 1-337970, Japanese Patent Publication No. 1-7. Examples thereof include hydrogenation catalysts described in Japanese Patent No. 53851, Japanese Patent Publication No. 2-9041 and the like.

  The block copolymer used in this embodiment may have a functional group-containing atomic group. The functional group is not particularly limited. For example, a hydroxyl group, a carboxyl group, a carbonyl group, a thiocarbonyl group, an acid halide group, an acid anhydride group, a thiocarboxylic acid group, an aldehyde group, a thioaldehyde group, a carboxylic acid ester group, Amide group, sulfonic acid group, sulfonic acid ester group, phosphoric acid group, phosphoric acid ester group, amino group, imino group, nitrile group, pyridyl group, quinoline group, epoxy group, thioepoxy group, sulfide group, isocyanate group, isothiocyanate Groups, halogenated silicon groups, alkoxysilicon groups, tin halide groups, boronic acid groups, boron-containing groups, boronate groups, alkoxytin groups, phenyltin groups and the like.

[Other additives]
The pressure-sensitive adhesive of the present embodiment contains the above-described block copolymer, and can further contain other components described later as necessary.

(Tackifier)
The adhesive composition concerning this embodiment can further contain 10-100 mass parts of tackifiers with respect to 100 mass parts of block copolymers. Thereby, there exists a tendency for the adhesive force of an adhesive composition to be more excellent, and it becomes a thing more suitable for the use for which higher adhesive force is calculated | required.

  “Tackifier” refers to a chemical compounded for the purpose of increasing the adhesive strength of the surface of the compound. The tackifier is not particularly limited. For example, rosin terpene resin, hydrogenated rosin terpene resin, coumarone resin, phenol resin, terpene-phenol resin, aromatic hydrocarbon resin, aliphatic carbonization A hydrogen resin etc. are mentioned. As specific examples of the tackifier, those described in “Rubber / Plastic Compounding Chemicals” (edited by Rubber Digest Co., Ltd.) can be used. A tackifier may be used individually by 1 type, or may use 2 or more types together.

  The content of the tackifier in the pressure-sensitive adhesive composition of the present embodiment is preferably 10 to 100 parts by mass, more preferably 20 to 80 parts by mass when the block copolymer is 100 parts by mass. More preferably, it is 30-70 mass parts. When the addition amount of the tackifier is 100 parts by mass or less, the pressure-sensitive adhesive composition has an appropriate pressure-sensitive adhesive force even after long-term sticking, and there is a tendency that no adhesive residue is generated during peeling. Moreover, it exists in the tendency which is more excellent by adhesive force by being 10 mass parts or more.

(Polyolefin resin)
The adhesive composition concerning this embodiment can further contain 10-100 mass parts of polyolefin resin with respect to 100 mass parts of block copolymers. By adding a polyolefin-based resin, there is an effect of suppressing the adhesiveness and adhesive force, and the change in the adhesive force can be reduced even by temperature treatment, and the desired adhesiveness and adhesive force tend to be stably obtained. It is in.

  The “polyolefin resin” refers to a chain hydrocarbon polymer having at least one double bond. The block copolymer used in the present embodiment is excellent in affinity with polyolefin resins, particularly polypropylene resins. When the adhesive composition of this embodiment is used for a surface protective film, the adhesive strength may be too high depending on the application. In such a case, the adhesive strength can be controlled by adding a polypropylene resin, and a pressure-sensitive adhesive composition having a desired adhesive strength can be produced. In general, polyolefin resins are classified into three types of homopolymers, random copolymers, and block copolymers in the form of copolymerization with a comonomer (mainly ethylene). The polyolefin resin to be added is not particularly limited, and two or more kinds may be used in combination. Moreover, it is preferable that content of polyolefin resin is 10-100 mass parts with respect to 100 mass parts of block copolymers used for this embodiment, More preferably, it is 20-80 mass parts, More preferably. Is 30 to 60 parts by mass or less. When the content of the polyolefin resin is in the above range, the adhesiveness and adhesive strength do not decrease excessively, which is preferable.

(Hydrogenated (hydrogenated) styrene elastomer)
The pressure-sensitive adhesive composition according to the present embodiment may further contain 10 to 100 parts by mass of a hydrogenated styrene-based elastomer other than the block copolymer of the present embodiment described above with respect to 100 parts by mass of the block copolymer. it can. Thereby, it exists in the tendency which is excellent by the balance of adhesiveness and adhesive force.

  In the present embodiment, the “hydrogenated styrene elastomer” refers to a copolymer of styrene and a hydrogenated conjugated diene compound. The hydrogenated styrene elastomer is not particularly limited. For example, styrene-butadiene-styrene (SBS), styrene-isoprene-styrene (SIS), styrene-butadiene random polymer (SBR) saturated by hydrogenation is saturated. Examples include ethylene-butylene-styrene (SEBS), styrene-ethylene-propylene-styrene (SEPS), styrene-ethylene-butylene (SEB), styrene-ethylene-propylene (SEP), and hydrogenated styrene-butadiene random polymer (HSBR). It is done.

  Further, the hydrogenated styrene elastomer is not particularly limited, but examples thereof include a hydroxyl group, a carboxyl group, a carbonyl group, a thiocarbonyl group, an acid halide group, an acid anhydride group, a thiocarboxylic acid group, an aldehyde group, a thioaldehyde group, Carboxylic acid ester group, amide group, sulfonic acid group, sulfonic acid ester group, phosphoric acid group, phosphoric acid ester group, amino group, imino group, nitrile group, pyridyl group, quinoline group, epoxy group, thioepoxy group, sulfide group, Use reactive elastomers with functional groups including isocyanate groups, isothiocyanate groups, silicon halide groups, alkoxysilicon groups, tin halide groups, boronic acid groups, boron-containing groups, boronate groups, alkoxytin groups, and phenyltin groups May be.

  The content of the hydrogenated styrene-based elastomer is preferably 10 to 100 parts by mass, more preferably 20 to 75 parts by mass, and still more preferably with respect to 100 parts by mass of the block copolymer used in the present embodiment. Is 30-50 parts by mass. When the content of the hydrogenated styrene-based elastomer is 100 parts by mass or less, moderate adhesive force and adhesiveness tend to be obtained. On the other hand, when the amount is 10 parts by mass or more, there is a tendency that the change in adhesiveness with time and the change in adhesive force with respect to the processing temperature are reduced.

(Ethylene vinyl acetate copolymer)
The pressure-sensitive adhesive composition of the present embodiment may further contain an ethylene vinyl acetate copolymer. The ethylene vinyl acetate copolymer is not particularly limited, and can be produced, for example, by radical copolymerization of ethylene and vinyl acetate under high temperature and high pressure conditions. The ethylene vinyl acetate copolymer has different properties depending on the vinyl acetate content, but is not particularly limited.

  The content of the ethylene vinyl acetate copolymer is preferably 100 parts by mass or less, more preferably 75 parts by mass, and even more preferably 50 parts by mass with respect to 100 parts by mass of the block copolymer used in the present embodiment. It is as follows. Moreover, it is preferable that content is 0 mass part or more. If the content of the ethylene vinyl acetate copolymer is within the above range, moderate adhesive strength and adhesiveness tend to be obtained.

(Acrylic copolymer)
The pressure-sensitive adhesive composition of the present embodiment may further contain an acrylic copolymer. The acrylic copolymer is not particularly limited, and examples thereof include copolymers of methyl acrylate, ethyl acrylate, methyl methacrylate, acrylonitrile with vinyl acetate, vinyl chloride, styrene, and the like.

  The content of the acrylic copolymer is preferably 100 parts by mass or less, more preferably 75 parts by mass, and still more preferably 50 parts by mass or less with respect to 100 parts by mass of the block copolymer used in the present embodiment. It is. Moreover, it is preferable that content is 0 mass part or more. If the content of the acrylic copolymer is within the above range, moderate adhesive strength and adhesiveness tend to be obtained.

(Softener)
The pressure-sensitive adhesive composition of the present embodiment may further contain a softening agent. By including a softener, the adhesiveness of the pressure-sensitive adhesive composition of the present embodiment can be improved. As the softener, either a mineral oil softener or a synthetic resin softener can be used.

  The mineral oil softener generally includes a mixture of aromatic hydrocarbons, naphthene hydrocarbons, and paraffin hydrocarbons. Paraffinic hydrocarbons with 50% or more carbon atoms in all carbon atoms are called paraffinic oils, naphthenic hydrocarbons with 30 to 45% carbon atoms are called naphthenic oils, An aromatic hydrocarbon having 35% or more carbon atoms is called an aromatic oil. Although it does not specifically limit as a mineral oil type softening agent, For example, the paraffinic oil which is a softening agent for rubber | gum is preferable.

  Although it does not specifically limit as a synthetic resin softening agent, For example, a polybutene, a low molecular-weight polybutadiene, etc. are mentioned as a preferable thing.

  It is preferable that content of the softening agent in the adhesive composition of this embodiment is 0-100 mass parts with respect to 100 mass parts of block copolymers. When the content is within the above range, bleeding of the softening agent can be further suppressed, and the adhesive force tends to be more excellent.

(Antioxidants, light stabilizers, etc.)
You may add stabilizers, such as antioxidant and a light stabilizer, to the adhesive composition of this embodiment.
The antioxidant is not particularly limited, and examples thereof include 2,6-di-t-butyl-4-methylphenol, n-octadecyl-3- (4′-hydroxy-3 ′, 5′-di-t- Butylphenyl) propionate, 2,2′-methylenebis (4-methyl-6-tert-butylphenol), 2,2′-methylenebis (4-ethyl-6-tert-butylphenol), 2,4-bis [(octylthio) Methyl] -o-cresol, 2-t-butyl-6- (3-t-butyl-2-hydroxy-5-methylbenzyl) -4-methylphenyl acrylate, 2,4-di-t-amyl-6 [1- (3,5-di-t-amyl-2-hydroxyphenyl) ethyl] phenyl acrylate, 2- [1- (2-hydroxy-3,5-di-tert-pentylphenyl)] acrylate Hindered phenol-based antioxidants such as dilauryl thiodipropionate, lauryl stearyl thiodipropionate pentaerythritol-tetrakis (β-lauryl thiopropionate) and the like; tris (nonylphenyl) Examples thereof include phosphorous antioxidants such as phosphite and tris (2,4-di-t-butylphenyl) phosphite.

  The light stabilizer is not particularly limited. For example, 2- (2′-hydroxy-5′-methylphenyl) benzotriazole, 2- (2′-hydroxy-3 ′, 5′-t-butylphenyl) benzo Benzotriazole ultraviolet absorbers such as triazole and 2- (2′-hydroxy-3 ′, 5′-di-t-butylphenyl) -5-chlorobenzotriazole; benzophenones such as 2-hydroxy-4-methoxybenzophenone UV absorbers; hindered amine light stabilizers and the like.

  The content of the antioxidant and the light stabilizer is preferably 10 parts by mass or less, more preferably 5 parts by mass, and still more preferably 100 parts by mass of the block copolymer used in the present embodiment. 2 parts by mass or less. Moreover, it is preferable that content is 0 mass part or more. When the content is 10 parts by mass or less, the adhesiveness that is stable for a long period of time is maintained, and more excellent thermal stability tends to be obtained.

(Pigments, waxes, thermoplastic resins, natural rubber, synthetic rubber)
The pressure-sensitive adhesive composition of the present embodiment includes other pigments such as bengara and titanium dioxide; waxes such as paraffin wax, microcristan wax, and low molecular weight polyethylene wax; amorphous polyolefin, ethylene-ethyl acrylate, as necessary. Thermoplastic resins such as polyolefin thermoplastic resins such as copolymers or low molecular weight vinyl aromatic thermoplastic resins; natural rubber; polyisoprene rubber, polybutadiene rubber, styrene-butadiene rubber, ethylene-propylene rubber, chloroprene rubber, Synthetic rubbers such as acrylic rubber, isoprene-isobutylene rubber, and polypentenamer rubber may be added. In addition, examples of the synthetic rubber include those described in “Rubber and plastic compounding chemicals” (edited by Rubber Digest Co., Ltd.).

[Method for producing pressure-sensitive adhesive composition]
The pressure-sensitive adhesive composition can be produced by a conventionally known method. For example, a melt kneading method using a general mixer such as a Banbury mixer, a single screw extruder, a twin screw extruder, a kneader, a multi-screw extruder, etc. A method of removing the solvent by heating after coating on the Kizai film is used.

  The pressure-sensitive adhesive composition of the present embodiment may be foamed in order to achieve lightening, softening, and adhesion improving effects. Examples of the foaming method include a chemical method, a physical method, and use of a thermal expansion type microballoon. Bubbles can be distributed inside the material by adding a chemical foaming agent such as an inorganic foaming agent or an organic foaming agent, a physical foaming agent, or the like, or by adding a thermal expansion type microballoon.

  Moreover, you may aim at weight reduction, softening, and the improvement of adhesiveness by adding a hollow filler (already inflated balloon).

[Surface protection film]
The surface protective film concerning this embodiment has a base film and the adhesive layer containing the adhesive composition of this embodiment mentioned above on this base film.

  The material for the base film is not particularly limited, and either a nonpolar resin or a polar resin can be used. Among these, the nonpolar resin is not particularly limited in terms of performance, price, and the like, and examples thereof include polyethylene, homo- or block polypropylene. Moreover, it does not specifically limit as polar resin, For example, polyester-type resins, such as a polyethylene terephthalate and a polybutylene terephthalate, a polyamide-type resin, an ethylene-vinyl acetate copolymer, its hydrolyzate, etc. are mentioned as a preferable thing.

  As for the thickness of the adhesive layer which comprises the surface protection film of this embodiment, 1 micrometer-100 micrometers are preferable, and 5-100 micrometers is more preferable. When the thickness of the pressure-sensitive adhesive layer is 100 μm or less, the capacity does not become too large, so that the handleability is good and more economical. Moreover, by being 1 micrometer or more, adhesiveness is more favorable and uniform thickness is obtained.

  The thickness of the base film is preferably 5 mm or less, more preferably 3 mm or less, still more preferably 1 mm or less, still more preferably 300 μm or less, and even more preferably 10 to 200 μm. . In general, a film having a thickness exceeding 300 μm is referred to as a “sheet”, but in the present specification, it is described as a film including these.

[Method for producing surface protective film]
As a manufacturing method of the surface protection film in this embodiment, the method of coating the melt or solution of an adhesive composition on the said base film, and the method by a film extruder are mentioned, for example.

  In the method of applying the solution of the pressure-sensitive adhesive composition, it can be produced by dissolving the pressure-sensitive adhesive composition in a solvent that can be dissolved, applying the solution on a base film using a coater, and drying the solvent by heating.

  In the method of melting and coating the pressure-sensitive adhesive composition, it can be produced by a method of coating the molten pressure-sensitive adhesive composition on a base film using a hot melt coater or the like. This method has the advantage that it can be applied to various substrate films having a glass transition temperature, melting point or softening point higher than the coating temperature.

  The method using the film extruder is not particularly limited, but the adhesive layer component and the thermoplastic resin component of the base film are made into two flows in the melt co-extruder, that is, for forming an adhesive layer. It can be manufactured by combining a fluid and a base material film forming fluid in a die port to form a single fluid and extruding it, and then combining the adhesive layer and the resin film layer. In the case of the method using a film extruder, the pressure-sensitive adhesive composition can be manufactured by dry blending each component of the pressure-sensitive adhesive composition in advance, so that the productivity is excellent.

  Hereinafter, the present invention will be described in detail with reference to specific examples and comparative examples, but the present invention is not limited to the following examples. First, evaluation methods and physical property measurement methods applied to Examples and Comparative Examples are shown below.

[I. (Evaluation of composition and structure of block copolymer)
(I-1) Styrene content, vinyl bond amount of conjugated diene, hydrogenation rate of double bond based on conjugated diene Styrene content in polymer, vinyl bond amount of conjugated diene, hydrogen of double bond based on conjugated diene The addition rate was calculated by measuring the measurement sample by nuclear magnetic resonance spectrum analysis (NMR) under the following conditions and calculating from the signal attribution of each component.

Measuring instrument: JNM-LA400 (manufactured by JEOL)
Solvent: Deuterated chloroform Measurement sample: Extracted sample before and after hydrogenation of polymer Sample concentration: 50 mg / mL
Observation frequency: 400 MHz
Chemical shift criteria: TMS (tetramethylsilane)
Pulse delay: 2.904 seconds Number of scans: 64 times Pulse width: 45 °
Measurement temperature: 26 ° C

(I-2) Weight average molecular weight, molecular weight distribution The number average molecular weight and weight average molecular weight of the block copolymer were measured by GPC (apparatus: LC-10 (manufactured by Shimadzu Corporation, trade name), column: TSKgelGMHXL (4. 6 mmID × 30 cm), 2 solvents, solvent: tetrahydrofuran), and the molecular weight was determined as a polystyrene-equivalent molecular weight using commercially available standard polystyrene. Moreover, molecular weight distribution was calculated | required as ratio of the obtained weight average molecular weight and number average molecular weight.

(I-3) Melt flow rate (MFR)
In accordance with ISO 1133, the measurement was performed under conditions of a temperature of 230 ° C. and a load of 2.16 kg (measurement unit: g / 10 minutes).

(I-4) Order-disorder transition temperature (ODT)
The order-disorder transition temperature (ODT) of the block copolymer is obtained by cutting a compression-molded sheet having a thickness of 2 mm into a circle having a diameter of 25 mm, and twisting the apparatus ARES (trade name, manufactured by TA Instruments). Specimen is set in the geometry of the type, 1.0% strain, fluctuation frequency (0.01-20Hz), dynamic storage elastic modulus (G '), loss elastic modulus (G'') at various temperatures Then, G ′ was determined from the slope of the straight line plotted against G ″ and the temperature at which the intercepts became the same.

[II. Characteristics of block copolymer or adhesive composition)
(II-1) Coating property The handling property in a hot melt coater and the film state (unevenness, wrinkles, etc.) were visually observed.
The coatability was evaluated as follows.
A: There was no wrinkle at the time of winding the film, and the surface state of the adhesive layer was uniform.
* 1: The adhesive layer was sticky, and wrinkles entered during film winding.
* 2: The surface of the adhesive layer was rough.

(II-2) Adhesiveness As a measuring device, probe tack tester NTS-4800: manufactured by Tester Sangyo Co., Ltd. was used. The surface protective film produced in the following Examples 1 to 10, Comparative Examples 1 to 6, and Reference Examples 1 to 3 was applied to the bobbin on which the double-sided tape with a weight of 10 g was applied, and the temperature was 23 ° C., CONTACT SPEED and PEELING SPEED. Was fixed at 1.0 cm / second and measured under two conditions of contact time of 5 seconds and 4 hours. The value of “change rate (%)” was calculated from adhesiveness after 4 hours / adhesiveness after 5 seconds × 100 (%). Moreover, the adhesiveness at low temperature was measured under the conditions of a temperature of 0 ° C. and a contact time of 5 seconds without changing SPEED. In addition, the value of adhesiveness read the maximum value of the data detected from the probe tack tester NTS-4800.

  When the measured value (N) of the adhesiveness after 23 seconds at 23 ° C. was 0.4 or more, it was judged to have excellent adhesiveness, and when it was 0.5 or more, it was judged to have superior adhesiveness. .

  Further, if the measured value (N) of the adhesiveness at 0 ° C. is 0.3 or more, the adhesive property does not depend on the temperature condition, and if it is 0.4 or more, the adhesive property does not depend on the temperature condition. I decided.

  Furthermore, if the change rate of the adhesiveness after 4 hours and 23 seconds at 23 ° C. is 200% or less, stable adhesiveness can be maintained for a long time, and if it is 170% or less, stable adhesiveness can be maintained for a long time. Judged that it was possible.

  “Adhesiveness” as used herein refers to tack (stickiness) and represents how easily it sticks.

(II-3) Adhesive strength (g / 10 mm)
As a measuring apparatus, a universal tensile testing machine “Tensilon STM-T-200BP: manufactured by Orientec Co., Ltd.” was used. The surface protective film produced in Examples 1 to 10, Comparative Examples 1 to 6, and Reference Examples 1 to 3 below was attached to a PMMA plate (arithmetic surface average roughness: 0.1 μm), and 180 ° C. at a temperature of 23 ° C. The peel test was performed under two conditions, immediately after pasting and after long-term adhesion.

  In the 180 degree peeling test, the surface protective film as a measurement sample was applied to a PMMA plate with a width of 25 mm, and the peeling force was measured at a peeling speed of 300 mm / min.

  In addition, the evaluation after adhesion for a long time was performed by putting a surface protective film on a PMMA plate, placing it in an oven at 40 ° C., 60 ° C., or 80 ° C. for 5 minutes, taking it out, and in 23 ° C. × 50% relative humidity. After leaving for 1 to 2 hours, a 180-degree peeling test was conducted for measurement. The evaluation immediately after pasting (untreated) was performed by pasting a surface protective film on a PMMA plate and leaving it in a 23 ° C. × 50% relative humidity for 1 to 2 hours, and then performing a 180 ° peeling test. The value of “change rate (%)” was calculated from untreated adhesive strength / 80 ° C. × adhesive strength after 5 minutes treatment × 100 (%).

  Under all conditions, the adhesive strength measurement value (N / 10 mm) in the case of the adhesive strength measurement value is 2.2 or more, and the adhesive strength is excellent, and if it is 3.0 or more, it is more excellent. Judged to have adhesive strength.

  Moreover, it was judged that if the rate of change was 200% or less, stable adhesiveness could be maintained for a long time, and if it was 150% or less, stable adhesiveness could be maintained for a long time.

  The “adhesive strength” referred to in the present specification refers to peel strength, and represents resistance when peeled.

(II-4) Adhesive residue The surface protective film produced in Examples 1 to 10 and Comparative Examples 1 to 6 below was pasted on a PMMA plate (arithmetic surface roughness: 1.1 μm), and 23 ° C. × 50. The rubber roll (diameter 10 cm) weighing 1 kg was rolled and pasted in% relative humidity. Thereafter, after the treatment at 80 ° C. for 5 minutes, the surface protective film was peeled off, and the state of the adhesive residue on the PMMA plate was evaluated. Evaluation of the adhesive residue was performed in four stages of ◎, ○, ×, and XX according to the following evaluation criteria.
(Evaluation criteria)
A: No adhesive residue that can be visually observed with respect to the peeled area (1 m ² ).
◯: One adhesive residue that can be visually observed with respect to the peeled area (1 m ² ).
X: The adhesive residue which can be observed visually with respect to a peeling area (1m < ² >) is a thing of 2-4 points | pieces.
Xx: The adhesive residue which can be visually observed with respect to a peeling area (1 m < ² >) is 5 or more points | pieces.

[III. Preparation of hydrogenation catalyst)
The hydrogenation catalyst used for the hydrogenation reaction of the block copolymer was prepared by the following method. Charge 1 L of dried and purified cyclohexane to a nitrogen-substituted reaction vessel, add 100 mmol of biscyclopentadienyl) titanium dichloride, add an n-hexane solution containing 200 mmol of trimethylaluminum with sufficient stirring, and bring it to room temperature. For about 3 days to prepare a hydrogenation catalyst.

[IV. Preparation of block copolymer)
<Polymer 1: Hydrogenated product of styrene-butadiene-styrene-butadiene (A1-B1-A2-B2)>
Here, A1, A2, B1, and B2 each represent the following polymer block.
A1, A2: Polystyrene polymer block B1, B2: Polybutadiene copolymer block Batch polymerization was performed using a stirrer with an internal volume of 10 L and a jacketed tank reactor. First, 1 L of cyclohexane was charged, and then n-butyllithium (hereinafter referred to as “Bu-Li”) was added to 0.10 parts by mass with respect to 100 parts by mass of all monomers, and N, N, N ′, N′-tetramethyl. Ethylenediamine (hereinafter referred to as “TMEDA”) was added in an amount of 1.8 mol with respect to 1 mol of Bu—Li, and sodium t-pentoxide (hereinafter referred to as “NaOAm”) was added in an amount of 0.045 mol with respect to 1 mol of TMEDA. As a first step, a cyclohexane solution (concentration 20% by mass) containing 9 parts by mass of styrene was added over 10 minutes, and then polymerized for another 10 minutes. During the polymerization, the temperature was controlled at 60 ° C. Next, as a second step, a cyclohexane solution (concentration: 20% by mass) containing 79 parts by mass of butadiene was added over 100 minutes, and then polymerized for another 10 minutes. During the polymerization, the temperature was controlled at 60 ° C. Next, as a third step, a cyclohexane solution (concentration: 20% by mass) containing 9 parts by mass of styrene was added over 10 minutes, and then polymerized for another 10 minutes. During the polymerization, the temperature was controlled at 60 ° C. Next, as a fourth step, a cyclohexane solution (concentration: 20% by mass) containing 3 parts by mass of butadiene was added over 5 minutes, and then polymerized for another 10 minutes. During the polymerization, the temperature was controlled at 60 ° C. A block copolymer was obtained as described above.

  Next, 100 ppm of the hydrogenation catalyst as titanium per 100 parts by mass of the block copolymer was added to the obtained block copolymer, and a hydrogenation reaction was performed at a hydrogen pressure of 0.7 MPa and a temperature of 70 ° C. Methanol was then added, and then octadecyl-3- (3,5-di-tert-butyl-4-hydroxyphenyl) propionate as a stabilizer was 0.3 parts by weight with respect to 100 parts by weight of the hydrogenated block copolymer. Added.

  The resulting hydrogenated block copolymer (Polymer 1) had a styrene content of 18% by mass, a vinyl bond content of the butadiene block of 76%, a hydrogenation rate of 98%, a terminal conjugated diene content of 3% by mass, and a weight average molecular weight of 105. , Molecular weight distribution 1.04, MFR28, ODT 200 ° C.

<Polymer 2: Hydrogenated product of styrene-butadiene-styrene (A1-B1-A2)>
Bu-Li is 0.096 parts by mass with respect to 100 parts by mass of all monomers, TMEDA is 0.55 mol with respect to 1 mol of Bu-Li, NaOAm is not added, and the amount of butadiene in the second step is 82 parts by mass. A hydrogenated block copolymer (Polymer 2) was produced in the same manner as in Polymer 1 except that a block copolymer having a 3 type structure was produced without performing the fourth step.

  The obtained hydrogenated block copolymer (polymer 2) had a styrene content of 18% by mass, a vinyl bond content of the butadiene block part of 51%, a hydrogenation rate of 99%, a terminal conjugated diene content of 0% by mass, and a weight average molecular weight of 110. , Molecular weight distribution 1.03, MFR4, ODT236 ° C.

<Polymer 3: Hydrogenated product of styrene-butadiene-styrene-butadiene (A1-B1-A2-B2)>
Similar to polymer 1 except that 0.099 parts by mass of Bu-Li is 100 parts by mass with respect to 100 parts by mass of all monomers, TMEDA is 1.19 mol with respect to 1 mol of Bu-Li, and 0.030 mol of NaOAm is added with respect to TMEDA. Thus, a hydrogenated block copolymer (Polymer 3) was produced.

  The resulting hydrogenated block copolymer (Polymer 3) had a styrene content of 18% by mass, a vinyl bond content of the butadiene block of 68%, a hydrogenation rate of 98%, a terminal conjugated diene content of 3% by mass, and a weight average molecular weight of 106. , Molecular weight distribution 1.04, MFR25, ODT203 ° C.

<Polymer 4: Hydrogenated product of styrene-butadiene-styrene-butadiene (A1-B1-A2-B2)>
The first and third steps are performed by adding Bu-Li to 0.102 parts by mass with respect to 100 parts by mass of all monomers, TMEDA to 2.6 mol with respect to 1 mol of Bu-Li, and 0.055 mol of NaOAm to TMEDA. The same procedure as for Polymer 1 was performed except that the amount of styrene was 10 parts by mass, the amount of butadiene in the second step was 78 parts by mass, and the amount of butadiene in the fourth step was 2 parts by mass. A coalescence (Polymer 4) was produced.

  The resulting hydrogenated block copolymer (Polymer 4) had a styrene content of 20% by mass, a vinyl bond content of the butadiene block of 95%, a hydrogenation rate of 99%, a terminal conjugated diene content of 2% by mass, and a weight average molecular weight of 102. , Molecular weight distribution 1.05, MFR25, ODT230 ° C.

<Polymer 5: Hydrogenated product of styrene-butadiene-styrene-butadiene (A1-B1-A2-B2)>
The amount of styrene in the first and third steps is 5 parts by mass, the amount of butadiene in the second step is 87 parts by mass, and the amount of butadiene in the fourth step. A hydrogenated block copolymer (Polymer 5) was produced in the same manner as in Polymer 1 except that the amount was 3 parts by mass.

  The resulting hydrogenated block copolymer (Polymer 5) had a styrene content of 10% by mass, a vinyl bond content of the butadiene block part of 75%, a hydrogenation rate of 99%, a terminal conjugated diene content of 2% by mass, and a weight average molecular weight of 144. , Molecular weight distribution 1.04, MFR99, ODT158 ° C.

<Polymer 6: Hydrogenated product of styrene-butadiene-styrene-butadiene (A1-B1-A2-B2)>
The same operation as in Polymer 1 was performed except that the amount of styrene in the first and third steps was 7.5 parts by mass, the amount of butadiene in the second step was 80 parts by mass, and the amount of butadiene in the fourth step was 5 parts by mass. A hydrogenated block copolymer (Polymer 6) was produced.

  The obtained hydrogenated block copolymer (polymer 6) had a styrene content of 15% by mass, a vinyl bond content of the butadiene block of 77%, a hydrogenation rate of 98%, a terminal conjugated diene content of 5% by mass, and a weight average molecular weight of 104. , Molecular weight distribution 1.04, MFR30, ODT181 ° C.

<Polymer 7: Hydrogenated product of styrene-butadiene-styrene-butadiene (A1-B1-A2-B2)>
Bu-Li is 0.110 parts by mass with respect to 100 parts by mass of all monomers, TMEDA is 1.20 mol with respect to 1 mol of Bu-Li, NaOAm is not added, and the amount of styrene in the first and third steps is 14 masses. The hydrogenated block copolymer (Polymer 7) was produced in the same manner as in Polymer 1 except that the amount of butadiene in the second step was 69 parts by mass and the amount of butadiene in the fourth step was 3 parts by mass. .

  The resulting hydrogenated block copolymer (Polymer 7) had a styrene content of 28% by mass, a vinyl bond content of 66% of the butadiene block, a hydrogenation rate of 98%, a terminal conjugated diene content of 3% by mass, and a weight average molecular weight of 89%. , Molecular weight distribution 1.05, MFR5, ODT 240 ° C.

<Polymer 8: Hydrogenated product of styrene-butadiene-styrene-butadiene (A1-B1-A2-B2)>
A hydrogenation catalyst was added in an amount of 87 ppm as titanium per 100 parts by mass of the block copolymer, a hydrogenation reaction was performed at a hydrogen pressure of 0.7 MPa and a temperature of 70 ° C., methanol was then added, and then octadecyl-3- ( The same operation as in Polymer 1 was carried out except that 0.3 part by mass of 3,5-di-t-butyl-4-hydroxyphenyl) propionate was added to 100 parts by mass of the hydrogenated block polymer, and the hydrogenated block A copolymer (Polymer 8) was produced.

  The resulting hydrogenated block copolymer (polymer 8) had a styrene content of 18% by mass, a vinyl bond content of 76% of the butadiene block, a hydrogenation rate of 86%, a terminal conjugated diene content of 3% by mass, and a weight average molecular weight of 105. , Molecular weight distribution 1.04, MFR32, ODT 190 ° C.

<Polymer 9: Hydrogenated product of styrene-butadiene-styrene (A1-B1-A2)>
Except that Bu-Li is 0.107 parts by mass with respect to 100 parts by mass of all monomers, the amount of butadiene in the second step is 82 parts by mass, and a block copolymer having a 3 type structure is manufactured without performing the fourth step. Carried out the same operations as in Polymer 1 to produce a hydrogenated block copolymer (Polymer 9).
The resulting hydrogenated block copolymer (Polymer 9) had a styrene content of 18% by mass, a vinyl bond content of the butadiene block part of 74%, a hydrogenation rate of 99%, a terminal conjugated diene content of 0% by mass, and a weight average molecular weight of 96. , Molecular weight distribution 1.05, MFR37, ODT208 ° C.

<Polymer 10: Hydrogenated product of styrene-butadiene-styrene-butadiene (A1-B1-A2-B2)>
A hydrogenated block copolymer (Polymer 10) was produced in the same manner as in Polymer 1 except that the amount of butadiene in the second step was 75 parts by mass and the amount of butadiene in the fourth step was 7 parts by mass.

  The resulting hydrogenated block copolymer (Polymer 10) had a styrene content of 18% by mass, a vinyl bond content of the butadiene block of 76%, a hydrogenation rate of 98%, a terminal conjugated diene content of 7% by mass, and a weight average molecular weight of 106. , Molecular weight distribution 1.05, MFR27, ODT185 ° C.

<Polymer 11: Hydrogenated product of styrene-butadiene-styrene-butadiene (A1-B1-A2-B2)>
A hydrogenated block copolymer (Polymer 11) was produced in the same manner as in Polymer 1 except that the amount of butadiene in the second step was 71 parts by mass and the amount of butadiene in the fourth step was 11 parts by mass.

  The obtained hydrogenated block copolymer (polymer 11) had a styrene content of 18% by mass, a vinyl bond content of the butadiene block of 75%, a hydrogenation rate of 99%, a terminal conjugated diene content of 11% by mass, and a weight average molecular weight of 105. , Molecular weight distribution 1.05, MFR27, ODT178 ° C.

<Polymer 12: Hydrogenated product of styrene-butadiene-styrene-butadiene (A1-B1-A2-B2)>
Bu-Li is 0.102 parts by mass with respect to 100 parts by mass of all monomers, the amount of styrene in the first and third steps is 10 parts by mass, the amount of butadiene in the second step is 75 parts by mass, A hydrogenated block copolymer (Polymer 12) was produced in the same manner as in Polymer 1 except that the amount of butadiene was changed to 5 parts by mass.

  The resulting hydrogenated block copolymer (polymer 12) had a styrene content of 20% by mass, a vinyl bond content of the butadiene block of 76%, a hydrogenation rate of 99%, a terminal conjugated diene content of 5% by mass, and a weight average molecular weight of 101. , Molecular weight distribution 1.03, MFR13, ODT 180 ° C.

<Polymer 13: Hydrogenated product of styrene-butadiene-styrene-butadiene (A1-B1-A2-B2)>
Similar to Polymer 1 except that Bu-Li is 0.113 parts by weight with respect to 100 parts by weight of all monomers, TMEDA is 1.20 mol with respect to 1 mol of Bu-Li, and 0.032 mol of NaOAm is added with respect to TMEDA. Thus, a hydrogenated block copolymer (Polymer 13) was produced.

  The resulting hydrogenated block copolymer (polymer 13) had a styrene content of 18% by mass, a vinyl bond content of the butadiene block of 70%, a hydrogenation rate of 99%, a terminal conjugated diene content of 3% by mass, and a weight average molecular weight of 88. , Molecular weight distribution 1.04, MFR51, ODT185 ° C.

[Example 1]
As the block copolymer, the above (Polymer 1) was melted at 200 ° C., and a hot melt coater (Accumulator Laboratories, Inc., model: LH-1) was used to make a 38 μm-thick polyester film (Toray Industries, Inc. The polymer melt was applied to the trade name Lumirror S10) to prepare a surface protective film having an adhesive layer.
The pressure-sensitive adhesive layer had a thickness of 15 μm.

  About this surface protective film, the coating property was observed, adhesiveness (23 ° C. × 5 seconds, 4 hours later, 0 ° C. × 5 seconds later), adhesive strength (untreated, 40 ° C., 60 ° C., 80 ° C. Measurement after each treatment for 5 minutes and measurement of adhesive residue were performed. The results are shown in Table 1 below.

[Comparative Example 1]
Instead of (Polymer 1), (Polymer 2) was used and melted at 200 ° C., a surface protective film was produced in the same manner as in Example 1, and each characteristic was measured. The measurement results are shown in Table 1 below.

[Example 2]
In place of (Polymer 1), (Polymer 3) was used and melted at 200 ° C., a surface protective film was produced in the same manner as in Example 1, and each characteristic was measured. The measurement results are shown in Table 1 below.

[Comparative Example 2]
In place of (Polymer 1), (Polymer 4) was used and melted at 200 ° C., a surface protective film was produced in the same manner as in Example 1, and each characteristic was measured. The measurement results are shown in Table 1 below.

[Comparative Example 3]
Instead of (Polymer 1), (Polymer 5) was used and melted at 200 ° C., a surface protective film was produced in the same manner as in Example 1, and each characteristic was measured. The measurement results are shown in Table 1 below.

Example 3
Instead of (Polymer 1), (Polymer 6) was used and melted at 200 ° C., a surface protective film was produced in the same manner as in Example 1, and each characteristic was measured. The measurement results are shown in Table 1 below.

[Comparative Example 4]
In place of (Polymer 1), (Polymer 7) was used, melted at 200 ° C., a surface protective film was produced in the same manner as in Example 1, and each characteristic was measured. The measurement results are shown in Table 1 below.

[Comparative Example 5]
Instead of (Polymer 1), (Polymer 8) was used and melted at 200 ° C., a surface protective film was produced in the same manner as in Example 1, and each characteristic was measured. The measurement results are shown in Table 1 below.

[ Reference Example 4 ]
Instead of (Polymer 1), (Polymer 9) was used and melted at 200 ° C., a surface protective film was produced in the same manner as in Example 1, and each characteristic was measured. The measurement results are shown in Table 1 below.

Example 5
Instead of (Polymer 1), (Polymer 10) was used and melted at 200 ° C., a surface protective film was produced in the same manner as in Example 1, and each characteristic was measured. The measurement results are shown in Table 1 below.

Example 6
In place of (Polymer 1), (Polymer 11) was used and melted at 200 ° C., a surface protective film was produced in the same manner as in Example 1, and each characteristic was measured. The measurement results are shown in Table 1 below.

[Comparative Example 6]
Instead of (Polymer 1), (Polymer 12) was used and melted at 200 ° C., a surface protective film was produced in the same manner as in Example 1, and each characteristic was measured. The measurement results are shown in Table 1 below.

Example 7
Instead of (Polymer 1), (Polymer 13) was used and melted at 200 ° C., a surface protective film was produced in the same manner as in Example 1, and each characteristic was measured. The measurement results are shown in Table 1 below.

Example 8
100 parts by mass of the above (Polymer 1) as a block copolymer and 50 parts by mass of Alcon P-115 (manufactured by Arakawa Chemical Industries, Ltd.) as a tackifier are melt-kneaded until uniform, and an adhesive composition is obtained. Was made. Using this pressure-sensitive adhesive composition, a surface protective film was produced in the same manner as in Example 1, and each characteristic was measured. The measurement results are shown in Table 2 below.

[Reference Example 1]
100 parts by mass of the above (Polymer 1) as a block copolymer and 150 parts by mass of Alcon P-115 (manufactured by Arakawa Chemical Industries, Ltd.) as a tackifier are melt-kneaded until uniform, and an adhesive composition is obtained. Was made. Using this pressure-sensitive adhesive composition, a surface protective film was produced in the same manner as in Example 1, and each characteristic was measured. The measurement results are shown in Table 2 below.

Example 9
100 parts by mass of the above (Polymer 1) as a block copolymer, 50 parts by mass of Alcon P-115 (Arakawa Chemical Industries, Ltd.) as a tackifier, and Sun Allomer PL500A (manufactured by Sun Allomer) as a polyolefin resin 50 parts by mass was melt-kneaded until uniform to prepare an adhesive composition. Using this pressure-sensitive adhesive composition, a surface protective film was produced in the same manner as in Example 1, and each characteristic was measured. The measurement results are shown in Table 2 below.

[Reference Example 2]
100 parts by mass of the above (Polymer 1) as a block copolymer, 50 parts by mass of Alcon P-115 (Arakawa Chemical Industries, Ltd.) as a tackifier, and Sun Allomer PL500A (manufactured by Sun Allomer) as a polyolefin resin 150 parts by mass was melt-kneaded until uniform to prepare an adhesive composition. Using this pressure-sensitive adhesive composition, a surface protective film was produced in the same manner as in Example 1, and each characteristic was measured. The measurement results are shown in Table 2 below.

Example 10
100 parts by mass of the above (Polymer 1) as a block copolymer and S.I. O. E. 20 parts by mass of SS605 (manufactured by Asahi Kasei Chemicals Corporation) was melt-kneaded until uniform to prepare an adhesive composition. Using this pressure-sensitive adhesive composition, a surface protective film was produced in the same manner as in Example 1, and each characteristic was measured. The measurement results are shown in Table 2 below.

[Reference Example 3]
100 parts by mass of the above (Polymer 1) as a block copolymer and S.I. O. E. 120 parts by mass of SS605 (manufactured by Asahi Kasei Chemicals Co., Ltd.) was melt-kneaded until uniform to prepare an adhesive composition. Using this pressure-sensitive adhesive composition, a surface protective film was produced in the same manner as in Example 1, and each characteristic was measured. The measurement results are shown in Table 2 below.

  As shown in Table 1, in Examples 1 to 10, all have excellent coating properties, and the adhesiveness and adhesive strength are maintained for a long time. Also, sufficient tackiness was obtained, and no adhesive residue was observed. In addition, as shown in Examples 8 to 10 and Reference Examples 1 to 3, it was shown that the pressure-sensitive adhesive composition of the present invention can exhibit appropriate adhesive strength and adhesiveness for each application.

  On the other hand, in Comparative Example 1, the total content of 1,2-bond amount and 3,4-bond amount in the conjugated diene monomer unit of the block copolymer (polymer 2) is 51%, Since the MFR is low and the ODT is high, the coating property, the adhesiveness, the adhesive change rate, the adhesive force, and the adhesive force change rate are inferior to those of the present invention.

  In Comparative Example 2, the total content of 1,2-bond amount and 3,4-bond amount in the conjugated diene monomer unit of the block copolymer (Polymer 4) is 95%, and the ODT is high. Therefore, the rate of change in adhesive strength was inferior to that of the present invention.

  In Comparative Example 3, the content of the vinyl aromatic monomer unit in the block copolymer (Polymer 5) is low, the MFR is high, and the ODT is low. It was inferior to the present invention in any of rate, adhesive strength, adhesive force change rate, and adhesive residue.

  Furthermore, in Comparative Example 4, since the amount of the vinyl aromatic monomer unit in the block copolymer (Polymer 7) is large, the MFR is low, and the ODT is high, the coatability, tackiness, and tackiness are increased. Both the rate of change and the adhesive strength were inferior to those of the present invention.

  In Comparative Example 5, since the hydrogenation rate of the double bond derived from the conjugated diene monomer of the block copolymer (Polymer 8) is low, the adhesive change rate, adhesive force, adhesive force change rate, paste Any remaining property was inferior to that of the present invention.

  In Comparative Example 6, since the MFR of the block copolymer (Polymer 12) was low, the tackiness was inferior to that of the present invention.

  Moreover, it turned out that Example 8 is excellent in coating property, the change rate of adhesiveness, the change rate of adhesive force, and adhesive residue property compared with the reference example 1. It turned out that Example 9 is excellent in the change rate of adhesiveness and adhesive force compared with the reference example 2. It turned out that Example 9 is excellent in adhesiveness and adhesive force compared with the reference example 3.

  The pressure-sensitive adhesive composition according to the present invention is a pressure-sensitive adhesive for bonding metal, glass, synthetic resin, etc., for the pressure-sensitive adhesive layer of a surface protective film that improves the scratch resistance of the surface and prevents the adhesion of dust, dust, dust, etc. As an industrial applicability.

Claims (6)

A pressure-sensitive adhesive composition comprising a block copolymer having a polymer block A mainly composed of vinyl aromatic monomer units and a polymer block B mainly composed of conjugated diene monomer units,
The block copolymer has two or more polymer blocks A and two or more polymer blocks B;
There is the polymer block B at at least one end of the block copolymer,
The content of the polymer block B at at least one end of the block copolymer is 0.5 to 9% by mass,
The block copolymer satisfies the following conditions (1) to (5):
Adhesive composition.
(1) The total content of 1,2-bond amount and 3,4-bond amount in the conjugated diene monomer unit is 65 to 90%.
(2) The content of the vinyl aromatic monomer unit is 12 to 25% by mass.
(3) The hydrogenation rate of the double bond derived from the conjugated diene monomer unit of the polymer block B is 90% or more. (4) The melt flow rate value (MFR) of the block copolymer is 25 to 60 g. / 10 minutes (5) The order-disorder transition temperature (ODT) of the block copolymer is 160 to 210 ° C. The block copolymer has two polymer blocks A1 and A2 and two polymer blocks B1 and B2.
The block copolymer has a structure represented by A1-B1-A2-B2,
The pressure-sensitive adhesive composition according to claim 1, wherein a mass ratio (B2 / B1) between the polymer block B1 and the polymer block B2 is 0.10 or less. For 100 parts by mass of the block copolymer,
The pressure-sensitive adhesive composition according to claim 1 or 2 , further comprising 10 to 100 parts by mass of a tackifier. For 100 parts by mass of the block copolymer,
The pressure-sensitive adhesive composition according to any one of claims 1 to 3 , further comprising 10 to 100 parts by mass of a polyolefin-based resin. For 100 parts by mass of the block copolymer,
The pressure-sensitive adhesive composition according to any one of claims 1 to 4 , further comprising 10 to 100 parts by mass of a hydrogenated styrene-based elastomer. A base film;
The surface protection film which has an adhesive layer containing the adhesive composition of any one of Claims 1-5 on this base film.