JP2014080533A - Adhesive composition - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide an adhesive composition excellent in adhesive performance such as adhesive force, processability, heat resistance performance and morphological stability.SOLUTION: An adhesive composition contains (a) a block copolymer containing (A) a polymer block mainly containing a vinyl aromatic monomer unit and (B) a polymer block mainly containing a conjugated diene monomer unit, and satisfying following requirements of (1) and (2): 15 to 25 mass%, (b) a tackifier resin: 35 to 65 mass%, (c) a styrenic polymer having a number average molecular weight of 2000 to 8000: 5 to 15 mass%, and (d) a softener: 5 to 30 mass%. (1) The percentage of the vinyl aromatic monomer in the (a) block copolymer is 25 to 45 mass%. (2) The vinyl binding amount in the (B) polymer block mainly containing the conjugated diene monomer unit is 25 to 45 mass%.

Description

  The present invention relates to an adhesive composition.

In recent years, vinyl aromatic monomer-conjugated diene monomer block copolymer (SBS: styrene-butadiene-styrene block copolymer, SIS: Styrene-isoprene-styrene block copolymers) are widely used. For example, Patent Documents 1 to 3 listed below disclose an adhesive composition or a pressure-sensitive adhesive composition using SBS.
However, the adhesive composition or pressure-sensitive adhesive composition using SBS or SIS has a high melt viscosity, and is shown in processing performance such as solubility and coatability and adhesive performance such as adhesive strength, and also in the softening point. The balance with the heat resistant deformation performance (hereinafter sometimes referred to as heat resistance or heat performance) may be insufficient.

In order to improve the performance balance, a method of blending a tackifier resin (tackifier) has been proposed.
However, even when the tackifying resin is blended, the adhesive composition or pressure-sensitive adhesive composition using SBS or SIS is not yet sufficient in the balance between processing performance and adhesive performance such as holding power, The melt viscosity is high and the coating property is insufficient. Further, the shape stability of the composition at room temperature is not sufficient.

  Thus, as techniques for improving these performances, the following Patent Documents 4 to 7 disclose adhesive compositions or pressure-sensitive adhesive compositions in which low-molecular polystyrene and α-olefin polymers are added as additives.

JP 2004-238548 A JP-A-3-285978 JP-A-62-86075 JP 2012-21078 A Special table 2010-506005 gazette Japanese Patent Laid-Open No. 11-50031 Special table 2003-501546 gazette

However, these adhesive compositions or pressure-sensitive adhesive compositions disclosed in Patent Documents 4 to 7 have not yet obtained sufficient characteristics in the balance between the adhesive performance and the shape stability. Improvement is desired.
Accordingly, in the present invention, in view of the above-mentioned problems of the prior art, there is provided an adhesive composition having excellent adhesive performance such as adhesive strength and having excellent processing performance, heat resistance performance and shape stability. For the purpose.

As a result of intensive studies in order to solve the above-mentioned problems, the present inventors have found that an adhesive composition containing a block copolymer having a specific structure, a tackifying resin, and a styrenic polymer having a specific molecular weight. However, the present inventors have found that the above problems can be effectively solved, and have completed the present invention.
That is, the present invention is as follows.

[1]
(A) A polymer block (A) mainly composed of a vinyl aromatic monomer unit and a polymer block (B) mainly composed of a conjugated diene monomer unit, which satisfy the following requirements (1) and (2) A block copolymer containing 15 to 25% by mass,
(1) The ratio of the vinyl aromatic monomer in said (a) block copolymer is 25-45 mass%.
(2) The vinyl bond content in the polymer block (B) mainly composed of the conjugated diene monomer unit is 25 to 45% by mass.
(B) Tackifying resin: 35 to 65% by mass;
(C) Styrenic polymer having a number average molecular weight of 2000 to 8000: 5 to 15% by mass;
(D) Softener: 5-30% by mass;
An adhesive composition comprising
[2]
The adhesive composition according to [1] above, wherein the block copolymer (a) has a glass transition temperature of −80 ° C. or higher and −70 ° C. or lower.
[3]
The adhesive composition according to [1] or [2], wherein the (b) tackifying resin includes a petroleum-based tackifying resin (b1) and a rosin-based tackifying resin (b2).
[4]
The block copolymer (a) comprises a polymer block (A) mainly composed of the vinyl aromatic monomer unit and a polymer block (B) mainly composed of a conjugated diene monomer unit ( The adhesive composition according to any one of [1] to [3] above, which contains a diblock structure consisting of A)-(B).
[5]
The adhesive composition according to any one of [1] to [4], wherein the styrenic polymer (c) contains styrene and / or α-methylstyrene as a polymerization monomer.

  ADVANTAGE OF THE INVENTION According to this invention, the adhesive composition which is excellent in adhesive properties, such as adhesive force, is excellent in processing performance, heat resistance performance, and shape stability can be provided.

  Hereinafter, a mode for carrying out the present invention (hereinafter simply referred to as “the present embodiment”) will be described in detail. The following embodiments are examples for explaining the present invention, and are not intended to limit the present invention to the following contents. The present invention can be appropriately modified within the scope of the gist.

[Adhesive composition]
The adhesive composition of this embodiment is
(A) A polymer block (A) mainly composed of a vinyl aromatic monomer unit and a polymer block (B) mainly composed of a conjugated diene monomer unit, which satisfy the following requirements (1) and (2) A block copolymer containing 15 to 25% by mass,
(B) Tackifying resin: 35 to 65% by mass;
(C) Styrenic polymer having a number average molecular weight of 2000 to 8000: 5 to 15% by mass;
(D) Softener: 5-30% by mass;
Is an adhesive composition containing
(1) The ratio of the vinyl aromatic monomer in said (a) block copolymer is 25-45 mass%.
(2) The vinyl bond content in the polymer block (B) mainly composed of the conjugated diene monomer unit is 25 to 45% by mass.

((A) Block copolymer)
The block copolymer (a) contained in the adhesive composition of the present embodiment is a polymer block (A) mainly composed of vinyl aromatic monomer units (hereinafter simply referred to as polymer block (A ), Blocks (A) and (A)) and polymer blocks (B) mainly composed of conjugated diene monomer units (hereinafter simply referred to as polymer blocks (B) and blocks (B)). , (B) may be described.).
From the viewpoint of achieving good holding power, a polymer block (A) mainly composed of at least two vinyl aromatic monomer units and a polymer block mainly composed of conjugated diene monomer units (B ) And a block copolymer.
(A) The block copolymer includes at least two polymer blocks (A) and a block copolymer containing the polymer block (B), and further one vinyl aromatic monomer unit. It is preferable to include a block copolymer containing a polymer block (A) mainly composed of a polymer block (B) mainly composed of one conjugated diene monomer unit.

The “mainly” of the polymer block (A) mainly composed of the vinyl aromatic monomer unit means that the vinyl aromatic monomer unit is 50% by mass or more, preferably 70% by mass or more, more preferably It means 85% by mass or more, more preferably 95% by mass or more, and is a copolymer block of a vinyl aromatic hydrocarbon and a conjugated diene compound or a vinyl aromatic homopolymer block.
In addition, the polymer block (A) in the block copolymer (a) includes a copolymer block of a vinyl aromatic hydrocarbon and a conjugated diene compound and a homopolymer block of a vinyl aromatic hydrocarbon as appropriate. It may exist in combination.
The “mainly” of the polymer block (B) mainly composed of the conjugated diene monomer unit means that the conjugated diene monomer unit is 50% by mass or more, preferably 70% by mass or more, more preferably 85% by mass. % Or more, more preferably 95% by mass or more, which is a copolymer block of a conjugated diene compound and a vinyl aromatic hydrocarbon or a conjugated diene homopolymer block.
In addition, the polymer block (B) in the block copolymer (a) is present by appropriately combining a copolymer block of a conjugated diene compound and a vinyl aromatic hydrocarbon and a conjugated diene homopolymer block. May be.

The (a) block copolymer has a polymer structure represented by the following general formula.
(AB) _n , (AB) _p A, ( _BA ) _q B, ( _AB ) _m X
In the above formula, A is a polymer block mainly composed of vinyl aromatic monomer units, and B is a polymer block mainly composed of conjugated diene monomer units.
The boundary between the A block and the B block does not necessarily have to be clearly distinguished.
N is an integer of 1 or more, preferably an integer of 2 or more, and p and q are integers of 1 or more.
m is any one of 2, 3, and 4, and X represents a residue of each coupling agent or a residue of an initiator such as each functional organolithium compound.

The vinyl aromatic hydrocarbon constituting the vinyl aromatic monomer unit in the polymer block (A) of the block copolymer is not limited to the following, for example, styrene, α-methylstyrene, Examples thereof include alkyl styrene such as p-methyl styrene and p-tertiary butyl styrene, paramethoxy styrene, vinyl naphthalene and the like. As the vinyl aromatic hydrocarbon, styrene is preferable from the viewpoints of price, mechanical strength, and holding power.
A vinyl aromatic hydrocarbon may be used individually by 1 type, and may use 2 or more types together.

The conjugated diene compound constituting the conjugated diene monomer unit in the polymer block (B) of the block copolymer is a diolefin having a conjugated double bond, and is not limited to the following. Examples include 1,3-butadiene, 2-methyl-1,3-butadiene (isoprene), 2,3-dimethyl-1,3-butadiene, 1,3-pentadiene, 1,3-hexadiene, and the like.
As the conjugated diene compound, 1,3-butadiene and isoprene are preferable.
A conjugated diene compound may be used individually by 1 type, and may use 2 or more types together.

Further, the block copolymer (a) constituting the adhesive composition of the present embodiment includes one vinyl aromatic unit from the viewpoint of balance between adhesive performance such as adhesive strength and processing performance. Includes a polymer (A) mainly composed of a monomer and a diblock copolymer ((A)-(B)) containing a polymer block (B) mainly composed of one conjugated diene monomer unit. It is preferable that
(A) Although the ratio of the diblock copolymer in a block copolymer is not specifically limited, It is preferable that it is 10-90 mass% in (a) block copolymer, More preferably, it is 15-85 mass%. More preferably, it is 20 to 80% by mass.

  A block copolymer containing a polymer block (A) mainly composed of at least two vinyl aromatic monomer units and a polymer block (B) mainly composed of a conjugated diene monomer unit; Both a polymer (A) mainly composed of one vinyl aromatic monomer and a block copolymer containing a polymer block (B) mainly composed of one conjugated diene monomer unit. The block copolymer can be produced by a method of polymerizing by a block copolymer coupling reaction, a method of mixing each solution after the completion of polymerization, or each block copolymer component obtained by drying with a roll or the like. The method of blending is mentioned.

In addition, when (a) the block copolymer includes a block copolymer of the above-described polymer structure (AB) _m X, a mixture at an arbitrary ratio can be obtained by controlling the coupling rate in the polymerization step. Can be obtained.

  The (a) block copolymer is obtained by hydrogenating a part or all of unsaturated double bonds derived from a conjugated diene that is a component of a conjugated diene monomer unit constituting the (a) block copolymer. It may be.

((A) Polymerization method of block copolymer)
The polymerization method of the (a) block copolymer is not particularly limited, and examples thereof include a polymerization method such as coordination polymerization, anionic polymerization, or cationic polymerization. Anionic polymerization is preferable from the viewpoint of easy control of the structure.
As a method for producing a block copolymer by anionic polymerization, a known method can be applied, and is not limited to the following. For example, Japanese Patent Publication No. 36-19286, Japanese Patent Publication No. 43-171979, Japanese Patent Publication No. Japanese Patent Publication No. 46-32415, Japanese Patent Publication No. 49-36975, Japanese Patent Publication No. 48-2423, Japanese Patent Publication No. 48-4106, Japanese Patent Publication No. 56-28925, Japanese Patent Publication No. 59-166518, Japanese Patent Publication No. Sho. The method described in 60-186577 etc. is mentioned.
By the above-described method, a block copolymer having a polymer structure of (AB) _n , (AB) _p A, and ( _BA ) _q B can be polymerized.
As described above, A is a polymer block mainly composed of vinyl aromatic monomer units, and B is a polymer block mainly composed of conjugated diene monomer units. The boundary between the A block and the B block does not necessarily have to be clearly distinguished. n is an integer of 1 or more, preferably an integer of 2 or more. p and q are integers of 1 or more.

In addition, a block copolymer having a polymer structure of (AB) _m X can be polymerized by known methods described in the various publications described above.
As described above, A is a polymer block mainly composed of vinyl aromatic monomer units, and B is a polymer block mainly composed of conjugated diene monomer units. The boundary between the A block and the B block does not necessarily have to be clearly distinguished. X represents a residue of each coupling agent or a residue of an initiator such as each functional group organolithium compound. m is 2, 3, or 4, and each numerical value shows a functional number.

The coupling agent is selected according to the value of m of the polymer structure of the target block copolymer: (AB) _m X.
Among the coupling agents, any known bifunctional coupling agent can be used without any particular limitation. For example, epoxy compounds, halogenated silicon compounds such as dichlorodimethylsilane and phenylmethyldichlorosilane, alkoxysilicon compounds such as dimethyldimethoxysilane and dimethyldiethoxysilane, tin compounds such as dichlorodimethyltin, methyl benzoate And ester compounds such as ethyl benzoate, phenyl benzoate, and phthalates, vinyl allenes such as divinylbenzene, and the like.

  Any known trifunctional coupling agent can be used without any particular limitation. Examples thereof include tin compounds such as methyltin trichloride and tributylchlorotin, silane compounds such as trimethoxysilane and triethoxysilane, and silicon halide compounds such as methyl silicon trichloride and trimethylchlorosilicon.

  Any known tetrafunctional coupling agent can be used without any particular limitation. For example, tin halide compounds such as tin tetrachloride, allyltin compounds such as tetraallyltin, tetra (2-octenyl) tin, tin compounds such as tetraphenyltin and tetrabenzyltin, silicon tetrachloride, tetrabromide Examples thereof include a silicon halide compound such as silicon, an alkoxysilicon compound such as tetraphenoxysilicon and tetraethoxysilicon.

The block copolymer (a) constituting the adhesive composition of the present embodiment can be produced by a solution polymerization method as an example, specifically, in an inert hydrocarbon solvent, organic lithium A method in which a vinyl aromatic hydrocarbon is polymerized using a compound as a polymerization initiator, a conjugated diene compound is then polymerized, and these operations are repeated in some cases, or a vinyl aromatic hydrocarbon-conjugated diene block copolymer is polymerized. It can be produced by a method of performing a coupling reaction using the above coupling agent.
At that time, the molecular weight of the block copolymer can be adjusted by controlling the amount of the organolithium compound.

  (A) In order to complete the polymerization reaction, the block copolymer is deactivated by adding water, alcohol, acid, etc., and the solution is subjected to, for example, steam stripping to separate the polymerization solvent. Obtained by drying.

  (A) The inert hydrocarbon solvent used in the polymerization step of the block copolymer is not limited to the following, but, for example, aliphatic such as butane, pentane, hexane, isopentane, heptane, octane, isooctane Hydrocarbons; cycloaliphatic hydrocarbons such as cyclopentane, methylcyclopentane, cyclohexane, methylcyclohexane, and ethylcyclohexane; hydrocarbon solvents such as aromatic hydrocarbons such as benzene, toluene, ethylbenzene, and xylene. These may be used alone or in combination of two or more.

  In addition, as the organic lithium compound used as a polymerization initiator in the polymerization step of the block copolymer (a), a known compound can be used, and is not particularly limited. Examples include lithium, n-butyllithium, sec-butyllithium, tert-butyllithium, phenyllithium, propenyllithium, and hexyllithium. In particular, n-butyl lithium and sec-butyl lithium are preferable. The organic lithium compound may be used alone or in a mixture of two or more.

  As described above, (a) the block copolymer is a part of the unsaturated double bond derived from the conjugated diene which is a component of the conjugated diene monomer unit constituting the block copolymer (a) or Although all may be hydrogenated, the hydrogenation method is not particularly limited, and is performed using a known technique.

  In the present embodiment, a step of deashing metals derived from a polymerization initiator or the like can be employed as necessary. Moreover, you may use reaction terminator, antioxidant, neutralizing agent, surfactant, etc. as needed.

((A) Content of block copolymer)
The adhesive composition of this embodiment contains a polymer (A) mainly composed of a vinyl aromatic monomer and a polymer block (B) mainly composed of a conjugated diene monomer unit (a ) The block copolymer is contained in an amount of 15 to 25% by mass, preferably 20 to 25% by mass.
(A) By containing 15% by mass or more of the block copolymer, excellent adhesive strength and heat resistance performance can be obtained in the adhesive composition of the present embodiment. Viscosity is obtained, and excellent processing performance is obtained.

((A) Specific structure of block copolymer)
(A) Content of the vinyl aromatic monomer unit of a block copolymer is 25-45 mass% from adhesive properties, such as adhesive force. Preferably it is 27.5-42.5 mass%, More preferably, it is 30-40 mass%.
(A) When the content of the vinyl aromatic monomer unit in the block copolymer is 25% by mass or more, a practically sufficient adhesive force and a good softening point can be obtained. When the unit content is 45% by mass or less, excellent adhesiveness (hereinafter referred to as tack) is obtained.

Moreover, in the adhesive composition of this embodiment, the vinyl bond amount of the polymer block (B) mainly composed of the conjugated diene monomer unit in the block copolymer (a) is 25 to 45% by mass. Preferably, it is 27-41 mass%, More preferably, it is 29-37 mass%.
Here, the amount of vinyl bonds refers to the mass ratio of the vinyl bonds constituting the conjugated diene compound in the polymer block (B) to the entire polymer block (B).
When the vinyl bond amount is 25% by mass or more, excellent shape stability can be obtained, and when the vinyl bond amount is 40% by mass or less, excellent holding force and tack can be obtained.
The vinyl bond amount of the conjugated diene compound in the block copolymer (B) is, for example, ethers or tertiary amines, such as ethylene glycol dimethyl ether, tetrahydrofuran, α-methoxytetrahydrofuran, N, N, Use one or a mixture of two or more selected from N ′, N′-tetramethylethylenediamine and the like, specifically, by introducing into a polymerization tank before introducing a conjugated diene monomer. Can do.

  The block copolymer (a) used in the present embodiment includes a modified polymer in which a polar group-containing functional group selected from nitrogen, oxygen, silicon, phosphorus, sulfur, and tin is bonded to the polymer, and a block copolymer A modified block copolymer in which the component is modified with a modifying agent such as maleic anhydride may also be included.

((A) Number average molecular weight of block copolymer)
The number average molecular weight of the block copolymer (a) is not particularly limited, but is preferably 40,000 to 300,000 from the viewpoint of the balance between adhesive strength, tack adhesive performance and processing performance, More preferably, it is 50,000-200,000, More preferably, it is 60,000-150,000.
(A) The number average molecular weight of a block copolymer can be measured by the method described in the Example mentioned later.

((A) Glass transition temperature of block copolymer)
The glass transition temperature of the block copolymer (a) is preferably −80 ° C. or higher and −70 ° C. or lower from the viewpoint of setting the vinyl bond amount of the polymer block (B) within the above-mentioned preferable range. More preferably, it is -80 degreeC or more and -72 degreeC or less, More preferably, it is -80 degreeC or more and -74 degreeC or less.
(A) The glass transition temperature of a block copolymer can be measured by the method described in the Example mentioned later.

((B) Tackifying resin)
The (b) tackifying resin constituting the adhesive composition of the present embodiment can be selected from (b1) petroleum-based tackifying resin and (b2) rosin depending on the intended use and required performance of the obtained adhesive composition. It is preferable from the viewpoint of balance between holding power and softening point.
For example, the (b1) petroleum-based tackifying resin is not limited to the following, and examples thereof include C5 petroleum resins, C5 / C9 copolymer petroleum resins, and hydrogenated petroleum resins. Of these, hydrogenated petroleum resins are particularly preferred.
(B2) Examples of the rosin resin include, but are not limited to, rosin ester, polymerized rosin, hydrogenated rosin ester, and the like. Of these, hydrogenated rosin esters are particularly preferred.

In the composition for an adhesive according to this embodiment, the content of the (b) tackifying resin is 35 to 65% by mass, preferably 37 to 63% by mass, and more preferably 40 to 60% by mass. %.
The content is 35% by mass or more from the viewpoint of adhesiveness and workability, and 65% by mass or less from the viewpoint of heat resistance.

((C) Styrenic polymer)
The adhesive composition of the present embodiment contains (c) a styrene polymer having a number average molecular weight of 2000 to 8000. Thereby, in the adhesive composition of this embodiment, adhesive performance, such as the outstanding adhesive force, tack, and holding power, is obtained, and the softening point is excellent and excellent heat resistance performance is obtained.
The number average molecular weight of a preferable styrenic polymer is 3,000 to 7,000, and the number average molecular weight of a more preferable styrenic polymer is 4,000 to 6,000.
The (c) styrenic polymer constituting the adhesive composition of the present embodiment is preferably a polymer mainly composed of styrene or α-methylstyrene, more preferably a styrene polymer. It is.
The number average molecular weight of the styrene polymer can be measured by gel permeation chromatography (GPC).

In the composition for an adhesive according to this embodiment, the content of (c) the styrenic polymer is 5 to 15% by mass, preferably 5 to 14% by mass, and more preferably 5 to 13%. % By mass.
The content is 5% by mass or more from the viewpoint of adhesive performance and workability, and 15% by mass or less from the viewpoint of shape stability.

((D) softener)
The softening agent (d) constituting the adhesive composition of the present embodiment is not particularly limited, and known paraffinic and naphthenic process oils and mixed oils thereof can be used. As a softener, paraffin type process oil (for example, Idemitsu Kosan Co., Ltd. product: PW-90) can be preferably used from a viewpoint of color tone.

In the composition for an adhesive according to this embodiment, the content of (d) the softening agent is 5 to 30% by mass, preferably 7 to 30% by mass, and more preferably 9 to 30% by mass. .
The content is 5% by mass or more from the viewpoint of adhesiveness and workability, and 30% by mass or less from the viewpoint of heat resistance.

As described above, the adhesive composition of this embodiment contains (a) a block copolymer, (b) a tackifier resin, (c) a styrene-based polymer, and (d) a softener, and is necessary. Depending on the above, it contains (other components) described later.
As described above, the adhesive composition of the present embodiment includes the block copolymer (a) of 15 to 25% by mass, the (b) tackifier resin: 35 to 65% by mass, and the above. (C) Styrenic polymer: 5 to 15% by mass and (d) softener: 5 to 30% by mass.
Preferably, for a good balance of adhesive performance, processing performance, heat resistance performance, and shape stability, (a) block copolymer: 20 to 25% by mass, (b) tackifying resin: 40 to 55 (C) Styrenic polymer: 10 to 15% by mass, (d) Softener: 10 to 25% by mass.

(Other ingredients)
If necessary, stabilizers such as antioxidants and light stabilizers and other additives can be added to the adhesive composition of the present embodiment.
Examples of the antioxidant include, but are not limited to, 2,6-di-tert-butyl-4-methylphenol, n-octadecyl-3- (4′-hydroxy-3 ′, 5 ′). -Di-t-butylphenyl) propionate, 2,2'-methylenebis (4-methyl-6-t-butylphenol), 2,2'-methylenebis (4-ethyl-6-t-butylphenol), 2,4- Bis [(octylthio) methyl] -0-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) ] Hindered phenol antioxidants such as acrylates; Sulfur antioxidants such as dilauryl thiodipropionate, lauryl stearyl thiodipropionate pentaerythritol tetrakis (β-lauryl thiopropionate); Tris (nonylphenyl) ) Phosphorous antioxidants such as phosphite and tris (2,4-di-t-butylphenyl) phosphite.
Although the addition amount of antioxidant is arbitrary, Preferably it is 5 mass parts or less with respect to 100 mass parts of adhesive compositions.

  Examples of the light stabilizer include, but are not limited to, 2- (2′-hydroxy-5′-methylphenyl) benzotriazole, 2- (2′-hydroxy-3 ′, 5′-t). -Butylphenyl) benzotriazole, benzotriazole ultraviolet absorbers such as 2- (2′-hydroxy-3 ′, 5′-di-t-butylphenyl) -5-chlorobenzotriazole, and 2-hydroxy-4- Examples include benzophenone ultraviolet absorbers such as methoxybenzophenone, hindered amine light stabilizers, and the like.

  In addition to the stabilizer, the adhesive composition of the present embodiment includes, as necessary, pigments such as bengara and titanium dioxide; waxes such as paraffin wax, microcrystalline wax, and low molecular weight polyethylene wax; amorphous polyolefin, Polyolefin or low molecular weight vinyl aromatic thermoplastic resins such as ethylene-ethyl acrylate copolymer; natural rubber; polyisoprene rubber, polybutadiene rubber, styrene-butadiene rubber, ethylene-propylene rubber, chloroprene rubber, acrylic rubber, isoprene -Even if a synthetic rubber such as a predetermined styrene-isoprene block copolymer other than the block copolymer constituting the isobutylene rubber, the polypentenamer rubber, and the adhesive composition of the present embodiment is added Good.

[Method for producing adhesive composition]
The adhesive composition of the present embodiment is prepared by mixing the above-described (a) block copolymer with (b) a tackifier resin, (c) a styrene polymer, and (d) a softener by a known method. Can be manufactured.
As a mixing method, for example, (a) a block copolymer, (b) a tackifier resin, (c) a styrenic polymer, and (d) a softener are uniformly mixed under heating conditions using a mixer, a kneader, or the like. The method of doing is mentioned.
The temperature in the mixing step is preferably 130 ° C to 210 ° C.
By setting it as 130 degreeC or more, (a) block copolymer can fully be melted and a favorable dispersion state is obtained. Moreover, by setting it as 210 degrees C or less, (a) bridge | crosslinking of a block copolymer, evaporation of the low molecular weight component of tackifying resin, etc. can be prevented effectively, and the outstanding adhesive property is obtained.
A more preferable mixing temperature is 140 ° C to 200 ° C, and more preferably 150 ° C to 190 ° C.
The mixing time in the mixing steps (a) to (d) is preferably 5 to 90 minutes.
By setting it as 5 minutes or more, each component can be disperse | distributed uniformly. Moreover, by setting it as 90 minutes or less, (a) bridge | crosslinking of a block copolymer, evaporation of the low molecular weight component of tackifying resin, etc. can be prevented effectively, and the outstanding adhesive property is obtained.
A more preferable mixing time is 10 minutes to 80 minutes, and further preferably 20 minutes to 70 minutes.

[Use of adhesive composition]
The adhesive composition of this embodiment is excellent in adhesive properties such as adhesive strength, processing performance, heat resistance performance and shape stability, and also in an excellent balance of these performances.
Taking advantage of these features, various adhesive tapes and labels, pressure-sensitive thin plates, pressure-sensitive sheets, surface protective sheets and films, various lightweight plastic molded product back glue, carpet fastening back glue, tile fastening back glue It is useful for adhesives, adhesive sheets and films, and adhesives for sanitary materials.

  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.

In the following examples and comparative examples, the characteristics and physical properties of the polymers were measured as follows.
[(1) Properties of block copolymer]
<(1-1) Content of vinyl aromatic monomer unit (styrene)>
A certain amount of a block copolymer (polymers 1 to 11 described later) is dissolved in chloroform, and measured with an ultraviolet spectrophotometer (manufactured by Shimadzu Corporation, UV-2450), resulting from a vinyl aromatic monomer (styrene). The vinyl aromatic monomer unit (styrene) content was calculated from the peak intensity of the absorption wavelength (262 nm) using a calibration curve.

<(1-2) Molecular weight>
Measurement was performed by gel permeation chromatography (GPC: apparatus is manufactured by Waters), tetrahydrofuran was used as a solvent, and measurement conditions were performed at a temperature of 35 ° C.
The molecular weight is a weight average molecular weight obtained by using a calibration curve (created using the peak molecular weight of standard polystyrene) obtained by measuring the molecular weight of the peak of the chromatogram from measurement of commercially available standard polystyrene.
The molecular weight when there are a plurality of peaks in the chromatogram refers to the average molecular weight obtained from the molecular weight of each peak and the composition ratio of each peak (obtained from the area ratio of each peak in the chromatogram).

<(1-3) Vinyl Bond Content of Conjugated Diene Polymer Block (Butadiene Part)>
Measurement was performed using an infrared spectrophotometer (Perkin Elmer model 1710), and measurement was performed by the Hampton method (described in “Analytical Chem., 21, 943 ('43)”).

<(1-4) Glass transition point>
It measured with the differential scanning calorimeter (DSC: apparatus is the product made from Mac Science), measurement conditions were temperature 200 degreeC--100 degreeC, and temperature rising conditions were performed at 20 degreeC / min. The glass transition point was read from the peak due to the conjugated diene site.

[(2) Measurement of melt viscosity, softening point, and penetration of adhesive composition]
The melt viscosity, softening point, and penetration of the adhesive compositions of Examples and Comparative Examples described below were measured as follows.
<(2-1) Processing performance (melt viscosity) of adhesive composition>
The melt viscosity of the adhesive composition was measured with a Brookfield viscometer (DV-III, manufactured by Brookfield) at a temperature of 160 ° C.
When the melt viscosity measurement value (mPa · s) is 800 or less, ◎ (practically excellent processing performance), 3000 or less is ◯ (practically sufficient processing performance), and a value exceeding 3000 × (practically insufficient) Machining performance).

<(2-2) Heat-resistant performance (softening point) of adhesive composition>
According to JIS-K2207, the softening point of the adhesive composition is filled with a sample in a specified ring, supported horizontally in water, a 3.5 g sphere is placed in the center of the sample, and the liquid temperature is 5 ° C / When the sample was raised at a speed of min, the temperature when the sample touched the bottom plate of the ring base with the weight of the sphere was measured.
When the measured softening point (° C) is 100 or more, ◎ (practically excellent heat resistance), 85 or more is ◯ (practically sufficient heat resistance), and less than 85 is x (practically insufficient heat resistance). It was determined that there was.

<(2-3) Shape stability (penetration)>
A cubic sample with a side of 5 cm was used, and the distance traveled by the needle with respect to the sample in 5 seconds was measured using a self-weight drop type penetration meter.
When the measured penetration value (1/10 mm) is 72 or less, ◎ (practically excellent performance), 80 or less is ◯ (practically sufficient performance), and 80 or more (practically insufficient performance) It was determined that there was.

[(3) Measurement of adhesive performance (adhesive strength, holding power, adhesiveness) of adhesive composition]
The adhesive compositions of Examples and Comparative Examples described below are dissolved in toluene, coated on a polyester film with an applicator, and then the toluene is completely evaporated at room temperature for 30 minutes and in an oven at 70 ° C. for 7 minutes. An adhesive tape having a thickness of 50 μm was produced.
The adhesive force, holding power, and tackiness (tack (loop tack)) of the adhesive composition were measured by the following methods.
<(3-1) Adhesive strength>
A 25 mm wide sample was reciprocated once with a 2 kg pressure roller and attached to a polyethylene (hereinafter referred to as PE) sheet, and the 180 ° peeling force was measured at a peeling speed of 300 mm / min to obtain the adhesive strength.
When the measured adhesive strength (N / 10 mm) is 9.0 or more, ◎ (practically excellent performance), 5.0 or more is ◯ (practical enough performance), and less than 5.0 is x (not practical) Sufficient performance).

<(3-2) Holding power>
As in (3-1) above, reciprocate once with a 2 kg pressure roller, attach the adhesive tape sample so that the area of 25 mm × 25 mm is in contact with the PE sheet, and apply a 1 kg load at 40 ° C. In the state where the adhesive tape and the PE sheet are attached, the adhesive surface is arranged so as to be perpendicular to the ground, and a load of 1 kg is applied to the adhesive tape side in the direction of gravity until the adhesive tape slips off. Was measured.
When the measured value (minutes) of the holding force is 700 or more, it is judged as ◎ (practical performance), 500 or more is judged as ○ (practical performance), and less than 500 is judged as x (practical performance). did.

<(3-3) Adhesiveness (loop tack)>
Using a loop-shaped sample of 250 mm length × 15 mm width, measurement was performed at a contact area to the PE sheet: 15 mm × 50 mm, an adhesion time of 3 sec, and an adhesion and peeling speed: 500 mm / min.
Adhesive measurement value (N / 15 mm) is 5.0 or more for ◎ (practical performance), 3.0 or more for ◯ (practical performance), and less than 3.0 x for practical use. Sufficient performance).

[Material of adhesive composition]
(Preparation of block copolymer)
<Polymer 1>
Washing, drying, and nitrogen-replacement of a stirring apparatus and jacketed tank reactor with an internal volume of 10 L, 3785 g of cyclohexane and 315 g of pre-purified styrene were charged, and warm water was passed through the jacket to bring the contents to about 61 ° C. Set.
Next, 0.50 mol of n-butyllithium cyclohexane solution (1.49 g in pure content) and TMEDA (N, N, N ′, N′-tetramethylethylenediamine) were added to 1 mol of n-butyllithium, and styrene was added. Polymerization of was started.
5 minutes after reaching the maximum temperature (73 ° C.) due to the polymerization of styrene, a cyclohexane solution containing 1,3-butadiene (585 g in pure content) was added to continue the polymerization, and the butadiene was almost completely polymerized. One minute after reaching the maximum temperature (73 ° C.), ethyl benzoate was added as a coupling agent for coupling.
Ten minutes after the addition of the coupling agent, 1.6 g of water was added to deactivate.
To the obtained block copolymer solution, 0.3 part by mass of octadecyl-3- (3,5-di-t-butyl-4-hydroxyphenyl) propionate is added with respect to 100 parts by mass of the block copolymer. Well mixed. Thereafter, the solvent was removed by heating to obtain polymer 1.
The obtained block copolymer has an AB structure of 73.5% by mass, an (AB) ₂ -X structure of 26.5% by mass, a styrene content of 35.6% by mass, and a butadiene part. Has an average vinyl bond content of 33% by mass, a glass transition point of -74.8 ° C., a weight average molecular weight of AB structure of 53,000, and a weight average molecular weight of (AB) ₂ -X structure of 10. It was 20,000.
In the above formula, A is a polymer block mainly composed of vinyl aromatic monomer units, B is a polymer block mainly composed of conjugated diene monomer units, and X is a residue or each functional group of each coupling agent. The residue of an initiator such as an organolithium compound is shown. The same shall apply hereinafter.

Moreover, the polymers 2-7 were manufactured by the method similar to the above.
<Polymer 2>
All were produced in the same manner as for Polymer 1 except that 0.6 mol of TMEDA was added.
The obtained block copolymer had an AB structure of 73.9% by mass, an (AB) ₂ -X structure of 26.1% by mass, a styrene content of 35.2% by mass, and a butadiene part. Has a vinyl bond content of 37 mass%, a glass transition point of -72.7 ° C., a weight average molecular weight of AB structure of 53,000, and a weight average molecular weight of (AB) ₂ -X structure of 10.2. It was ten thousand.

<Polymer 3>
All were produced in the same manner as for Polymer 1 except that 0.42 mol of TMEDA was added.
The obtained block copolymer had an AB structure of 73.7% by mass, an (AB) ₂ -X structure of 26.3% by mass, a styrene content of 35.5% by mass, and a butadiene part. Has a vinyl bond amount of 29 mass%, a glass transition point of -77.1 ° C., an AB structure weight average molecular weight of 53,000, and an (AB) ₂ -X structure weight average molecular weight of 10.1. It was ten thousand.

<Polymer 4>
All were produced in the same manner as for Polymer 1 except that 0.7 mol of TMEDA was added.
The obtained block copolymer had an AB structure of 74.8% by mass, an (AB) ₂ -X structure of 25.2% by mass, a styrene content of 35.3% by mass, and a butadiene part. Has a vinyl bond content of 44% by mass, a glass transition point of −70.1 ° C., a weight average molecular weight of AB structure of 53,000, and a weight average molecular weight of (AB) ₂ -X structure of 10.1. It was ten thousand.

<Polymer 5>
All were produced in the same manner as for Polymer 1 except that 0.35 mol of TMEDA was added.
The obtained block copolymer has an AB structure of 74.0% by mass, an (AB) ₂ -X structure of 26.0% by mass, a styrene content of 35.0% by mass, and a butadiene part. Has a vinyl bond content of 26% by mass, a glass transition point of -80.0 ° C., a weight average molecular weight of AB structure of 53,000, and a weight average molecular weight of (AB) ₂ -X structure of 10.2. It was ten thousand.

<Polymer 6>
All were produced in the same manner as for Polymer 1 except that 0.75 mol of TMEDA was added.
The obtained block copolymer has an AB structure of 75.7% by mass, an (AB) ₂ -X structure of 24.3% by mass, a styrene content of 35.5% by mass, and a butadiene part. Has a vinyl bond amount of 46.8% by mass, a glass transition point of −69.0 ° C., a weight average molecular weight of AB structure of 52,000, and a weight average molecular weight of (AB) ₂ -X structure of 10 It was 0.0 million.

<Polymer 7>
All were produced in the same manner as for Polymer 1 except that 0.3 mol of TMEDA was added.
The obtained block copolymer had an AB structure of 75.5% by mass, an (AB) ₂ -X structure of 24.5% by mass, a styrene content of 34.8% by mass, and a butadiene part. Has a vinyl bond content of 20% by mass, a glass transition point of −81.1 ° C., a weight average molecular weight of AB structure of 53,000, and a weight average molecular weight of (AB) ₂ -X structure of 10.1. It was ten thousand.

<Polymer 8>
Washing, drying, and nitrogen-replacement of a stirring apparatus and jacketed tank reactor with an internal volume of 10 L, 3785 g of cyclohexane and 315 g of pre-purified styrene were charged, and warm water was passed through the jacket to bring the contents to about 61 ° C. Set.
Then, n-butyllithium cyclohexane solution (1.49 g in pure content) was added to initiate polymerization of styrene.
5 minutes after reaching the maximum temperature (73 ° C.) due to the polymerization of styrene, a cyclohexane solution containing 1,3-butadiene (585 g in pure content) was added to continue the polymerization, and the butadiene was almost completely polymerized. One minute after reaching the maximum temperature (86 ° C.), ethyl benzoate was added as a coupling agent for coupling.
Ten minutes after the addition of the coupling agent, 1.6 g of water was added to deactivate.
To the obtained block copolymer solution, 0.3 part by mass of octadecyl-3- (3,5-di-t-butyl-4-hydroxyphenyl) propionate is added with respect to 100 parts by mass of the block copolymer. Well mixed. Thereafter, the solvent was removed by heating to obtain polymer 8.
The obtained block copolymer has an AB structure of 71.4% by mass, an (AB) ₂ -X structure of 28.6% by mass, a styrene content of 34.6% by mass, and a butadiene part. Has a vinyl bond content of 11% by mass, a glass transition point of -89.1 ° C., a weight average molecular weight of AB structure of 71,000, and a weight average molecular weight of (AB) ₂ -X structure of 13.7. It was ten thousand.

Further, a polymer 9 was obtained by the same method as that for the polymer 8.
<Polymer 9>
All were produced in the same manner as the polymer 8 except that the amount of styrene introduced was 294 g and a cyclohexane solution containing 1,3-butadiene (390 g in pure content) was added.
The resulting block copolymer has an AB structure of 65.0 mass%, an (AB) _2- X structure of 35.0 mass%, a styrene content of 43.0 mass%, and a butadiene part. The vinyl bond amount is 11% by mass, the glass transition point is −88 ° C., the weight average molecular weight of AB structure is 54,000, and the weight average molecular weight of (AB) ₂ -X structure is 107,000. there were.

<Polymer 10>
A stirrer and jacketed tank reactor with an internal volume of 10 L were washed, dried, and purged with nitrogen, charged with 5720 g of cyclohexane and 144 g of pre-purified styrene, and warm water was passed through the jacket to bring the contents to about 61 ° C. Set.
Next, 0.35 mol of n-butyllithium cyclohexane solution (1.49 g in pure content) and TMEDA (N, N, N ′, N′-tetramethylethylenediamine) are added to 1 mol of n-butyllithium, and styrene is added. Polymerization of was started.
5 minutes after reaching the maximum temperature (73 ° C.) due to the polymerization of styrene, a cyclohexane solution containing 1,3-butadiene (560 g in pure content) was added to continue the polymerization, and the butadiene was polymerized almost completely. 15 minutes after reaching the maximum temperature (73 ° C.), 144 g of styrene was added again and the polymerization was continued. After the styrene was almost completely polymerized, the polymerization was continued for another 15 minutes to complete the polymerization.
Thereafter, 1.6 g of water was added to deactivate.
To the obtained block copolymer solution, 0.3 part by mass of octadecyl-3- (3,5-di-t-butyl-4-hydroxyphenyl) propionate is added with respect to 100 parts by mass of the block copolymer. Well mixed. Thereafter, the solvent was removed by heating to obtain polymer 10.
The resulting block copolymer has an ABA structure of 100% by mass, a styrene content of 34.0% by mass, a vinyl bond content of the butadiene part of 27% by mass, and a glass transition point of -79. The weight average molecular weight of the ABA structure at 5 ° C. was 76,000.

In addition, polymer 11 was obtained by the same method as polymer 10 described above.
<Polymer 11>
All of them were produced in the same manner as the polymer 10 except that 0.3 mol of the TMEDA was added.
The resulting block copolymer has an ABA structure of 100% by mass, a styrene content of 35.1% by mass, a butadiene portion vinyl bond content of 20% by mass, and a glass transition point of −81 ° C. The weight average molecular weight of the ABA structure was 77,000.

(Petroleum tackifier resin (b1))
Alcon M100 (manufactured by Arakawa Chemical Industries, Ltd.) was used as the petroleum-based tackifying resin (b1).

(Rosin-based tackifier resin (b2))
Pine Crystal KE-359 (Arakawa Chemical Industries, Ltd.) was used as the rosin-based tackifying resin (b2).

(Styrene polymer)
As a styrene polymer, Hymer ST95 (manufactured by Sanyo Chemical Co., Ltd., number average molecular weight 4700) of low molecular polystyrene was used.

(Softener)
As a softener, Diana Process Oil PW-90 (manufactured by Idemitsu Kosan Co., Ltd.) was used.

[Example 1]
Petroleum-based tackifier resin (b1) is 40% by mass, rosin-based tackifier resin (b2) is 10% by mass, styrene-based polymer is 10% by mass, and softener is 20% by mass with respect to 20% by mass of polymer 1. The mixture was mixed at a compounding ratio of% to produce an adhesive composition. The melt viscosity, softening point, and penetration were measured by the method described above [(2) Measurement of melt viscosity, softening point, and penetration of adhesive composition]. The obtained results are shown in Tables 1 and 3.
Moreover, the adhesive tape was manufactured according to the method of the above-mentioned [(3) Measurement of adhesive force, holding power, and tackiness of adhesive composition], and adhesive strength, holding power, and tackiness were measured. The obtained results are shown in Tables 1 and 3.

[Example 2]
Petroleum tackifier resin (b1) is 40 wt%, rosin tackifier resin (b2) is 10 wt%, styrene polymer is 10 wt%, and softener is 20 wt% with respect to 20 wt% of polymer 2. The mixture was mixed at a compounding ratio of% to produce an adhesive composition. In the same manner as in Example 1, melt viscosity, softening point, penetration, adhesive force, holding force, and tackiness were measured. The obtained results are shown in Table 1.

Example 3
Petroleum-based tackifier resin (b1) is 40% by mass, rosin-based tackifier resin (b2) is 10% by mass, styrene-based polymer is 10% by mass, and softener is 20% by mass with respect to 20% by mass of polymer 3. The mixture was mixed at a compounding ratio of% to produce an adhesive composition. In the same manner as in Example 1, melt viscosity, softening point, penetration, adhesive force, holding force, and tackiness were measured. The obtained results are shown in Table 1.

Example 4
Petroleum-based tackifier resin (b1) is 40% by mass, rosin-based tackifier resin (b2) is 10% by mass, styrene-based polymer is 10% by mass, and softener is 20% by mass with respect to 20% by mass of polymer 4. The mixture was mixed at a compounding ratio of% to produce an adhesive composition. In the same manner as in Example 1, melt viscosity, softening point, penetration, adhesive force, holding force, and tackiness were measured. The obtained results are shown in Table 1.

Example 5
The polymer 5 is 20% by mass, the petroleum-based tackifier resin (b1) is 40% by mass, the rosin-based tackifier resin (b2) is 10% by mass, the styrene polymer is 10% by mass, and the softener is 20% by mass. The mixture was mixed at a compounding ratio of% to produce an adhesive composition. In the same manner as in Example 1, melt viscosity, softening point, penetration, adhesive force, holding force, and tackiness were measured. The obtained results are shown in Table 1.

Example 6
The polymer 10 is 20% by mass, the petroleum-based tackifier resin (b1) is 40% by mass, the rosin-based tackifier resin (b2) is 10% by mass, the styrene polymer is 10% by mass, and the softener is 20% by mass. The mixture was mixed at a compounding ratio of% to produce an adhesive composition. In the same manner as in Example 1, melt viscosity, softening point, penetration, adhesive force, holding force, and tackiness were measured. The obtained results are shown in Table 1.

Example 7
30% by mass of petroleum-based tackifier resin (b1), 10% by mass of rosin-based tackifier resin (b2), 10% by mass of styrene-based polymer, and 25% by mass of softener with respect to 25% by mass of polymer 1 The mixture was mixed at a compounding ratio of% to produce an adhesive composition. In the same manner as in Example 1, melt viscosity, softening point, penetration, adhesive force, holding force, and tackiness were measured. The obtained results are shown in Table 2.

Example 8
45% by mass of petroleum-based tackifier resin (b1), 10% by mass of rosin-based tackifier resin (b2), 15% by mass of styrene-based polymer, and 15% by mass of softener with respect to 15% by mass of polymer 1 The mixture was mixed at a compounding ratio of% to produce an adhesive composition. In the same manner as in Example 1, melt viscosity, softening point, penetration, adhesive force, holding force, and tackiness were measured. The obtained results are shown in Table 2.

Example 9
Petroleum-based tackifier resin (b1) is 30% by mass, rosin-based tackifier resin (b2) is 10% by mass, styrene-based polymer is 10% by mass, and softener is 25% by mass with respect to 25% by mass of polymer 4. The mixture was mixed at a compounding ratio of% to produce an adhesive composition. In the same manner as in Example 1, melt viscosity, softening point, penetration, adhesive force, holding force, and tackiness were measured. The obtained results are shown in Table 2.

[Comparative Example 1]
Petroleum tackifier resin (b1) is 40 wt%, rosin tackifier resin (b2) is 10 wt%, styrene polymer is 10 wt%, and softener is 20 wt% with respect to 20 wt% of polymer 6. The mixture was mixed at a compounding ratio of% to produce an adhesive composition. In the same manner as in Example 1, melt viscosity, softening point, penetration, adhesive force, holding force, and tackiness were measured. The obtained results are shown in Table 1.

[Comparative Example 2]
Petroleum tackifier resin (b1) is 40 wt%, rosin tackifier resin (b2) is 10 wt%, styrene polymer is 10 wt%, and softener is 20 wt% with respect to 20 wt% of polymer 7. The mixture was mixed at a compounding ratio of% to produce an adhesive composition. In the same manner as in Example 1, melt viscosity, softening point, penetration, adhesive force, holding force, and tackiness were measured. The obtained results are shown in Table 1.

[Comparative Example 3]
Petroleum-based tackifier resin (b1) is 40% by mass, rosin-based tackifier resin (b2) is 10% by mass, styrene-based polymer is 10% by mass, and softener is 20% by mass with respect to 20% by mass of the polymer 11. The mixture was mixed at a compounding ratio of% to produce an adhesive composition. In the same manner as in Example 1, melt viscosity, softening point, penetration, adhesive force, holding force, and tackiness were measured. The obtained results are shown in Table 1.

[Comparative Example 4]
The polymer 8 was mixed at a blending ratio of 60% by mass of the petroleum-based tackifier resin (b1) and 20% by mass of the softening agent with respect to 20% by mass to produce an adhesive composition. In the same manner as in Example 1, melt viscosity, softening point, penetration, adhesive force, holding force, and tackiness were measured. The obtained results are shown in Table 2.

[Comparative Example 5]
The polymer 9 is mixed at a blending ratio of 40% by mass of the petroleum-based tackifier resin (b1), 15% by mass of the rosin-based tackifier resin (b2), and 20% by mass of the softener, with respect to 25% by mass of the polymer 9. An adhesive composition was produced. In the same manner as in Example 1, melt viscosity, softening point, penetration, adhesive force, holding force, and tackiness were measured. The obtained results are shown in Table 2.

[Comparative Example 6]
Petroleum-based tackifier resin (b1) is 35% by mass, rosin-based tackifier resin (b2) is 15% by mass, styrene-based polymer is 15% by mass, and softener is 20% by mass with respect to 15% by mass of polymer 6. The mixture was mixed at a compounding ratio of% to produce an adhesive composition. In the same manner as in Example 1, melt viscosity, softening point, penetration, adhesive force, holding force, and tackiness were measured. The obtained results are shown in Table 2.

[Comparative Example 7]
Petroleum tackifier resin (b1) is 30 wt%, rosin tackifier resin (b2) is 25 wt%, styrene polymer is 5 wt%, and softener is 20 wt% with respect to 20 wt% of polymer 6. The mixture was mixed at a compounding ratio of% to produce an adhesive composition. In the same manner as in Example 1, melt viscosity, softening point, penetration, adhesive force, holding force, and tackiness were measured. The obtained results are shown in Table 2.

[Comparative Example 8]
30% by mass of polymer 1 with respect to 30% by mass of petroleum-based tackifier resin (b1), 10% by mass of rosin-based tackifier resin (b2), 10% by mass of styrene polymer, and 20% of softener The mixture was mixed at a compounding ratio of% to produce an adhesive composition. In the same manner as in Example 1, melt viscosity, softening point, penetration, adhesive force, holding force, and tackiness were measured. The obtained results are shown in Table 3.

[Comparative Example 9]
Petroleum tackifier resin (b1) is 45 wt%, rosin tackifier resin (b2) is 15 wt%, styrene polymer is 10 wt%, and softener is 20 wt% with respect to 10 wt% of polymer 1. The mixture was mixed at a compounding ratio of% to produce an adhesive composition. In the same manner as in Example 1, melt viscosity, softening point, penetration, adhesive force, holding force, and tackiness were measured. The obtained results are shown in Table 3.

[Comparative Example 10]
Petroleum tackifier resin (b1) is 50 wt%, rosin tackifier resin (b2) is 20 wt%, styrene polymer is 5 wt%, and softener is 10 wt% with respect to 15 wt% of polymer 1. The mixture was mixed at a compounding ratio of% to produce an adhesive composition. In the same manner as in Example 1, melt viscosity, softening point, penetration, adhesive force, holding force, and tackiness were measured. The obtained results are shown in Table 3.

[Comparative Example 11]
Petroleum-based tackifier resin (b1) is 20% by mass, rosin-based tackifier resin (b2) is 10% by mass, styrene-based polymer is 15% by mass, and softener is 30% by mass with respect to 25% by mass of polymer 1. The mixture was mixed at a compounding ratio of% to produce an adhesive composition. In the same manner as in Example 1, melt viscosity, softening point, penetration, adhesive force, holding force, and tackiness were measured. The obtained results are shown in Table 3.

[Comparative Example 12]
Petroleum-based tackifier resin (b1) is 30% by mass, rosin-based tackifier resin (b2) is 10% by mass, styrene-based polymer is 20% by mass, and softener is 20% by mass with respect to 20% by mass of polymer 1. The mixture was mixed at a compounding ratio of% to produce an adhesive composition. In the same manner as in Example 1, melt viscosity, softening point, penetration, adhesive force, holding force, and tackiness were measured. The obtained results are shown in Table 3.

[Comparative Example 13]
With respect to 25% by mass of the polymer 1, the petroleum-based tackifying resin (b1) is mixed at 40% by mass, the rosin-based tackifying resin (b2) is mixed at 15% by mass, and the softening agent is mixed at a mixing ratio of 20% by mass, An adhesive composition was produced. In the same manner as in Example 1, melt viscosity, softening point, penetration, adhesive force, holding force, and tackiness were measured. The obtained results are shown in Table 3.

  The compositions for adhesives of Examples 1 to 9 are excellent in adhesive performance, processing performance, heat resistance performance and shape stability composed of adhesive strength, holding power and tackiness, and in an excellent balance of these performances. I found out.

  The adhesive composition of the present invention includes various adhesive tapes / labels, pressure-sensitive thin plates, pressure-sensitive sheets, surface protective sheets / films, back paste for fixing various lightweight plastic molded products, back paste for carpet fixing, tile fixing It has industrial applicability as adhesives for adhesives, adhesives, adhesive sheets and films, and adhesives for sanitary materials.

Claims (5)

(A) A polymer block (A) mainly composed of a vinyl aromatic monomer unit and a polymer block (B) mainly composed of a conjugated diene monomer unit, which satisfy the following requirements (1) and (2) A block copolymer containing 15 to 25% by mass,
(1) The ratio of the vinyl aromatic monomer in said (a) block copolymer is 25-45 mass%.
(2) The vinyl bond content in the polymer block (B) mainly composed of the conjugated diene monomer unit is 25 to 45% by mass.
(B) Tackifying resin: 35 to 65% by mass;
(C) Styrenic polymer having a number average molecular weight of 2000 to 8000: 5 to 15% by mass;
(D) Softener: 5-30% by mass;
An adhesive composition comprising   The adhesive composition of Claim 1 whose glass transition temperature of the said block copolymer (a) is -80 degreeC or more and -70 degreeC or less.   The pressure-sensitive adhesive composition according to claim 1 or 2, wherein the (b) tackifying resin comprises a petroleum-based tackifying resin (b1) and a rosin-based tackifying resin (b2).   The block copolymer (a) comprises a polymer block (A) mainly composed of the vinyl aromatic monomer unit and a polymer block (B) mainly composed of a conjugated diene monomer unit ( The adhesive composition as described in any one of Claims 1 thru | or 3 containing the diblock structure which consists of A)-(B).   The adhesive composition according to any one of claims 1 to 4, wherein the styrenic polymer (c) contains styrene and / or α-methylstyrene as a polymerization monomer.