JPWO2012050046A1 - Block copolymer for adhesive, method for producing the same, and adhesive composition - Google Patents

Abstract

[PROBLEMS] A block copolymer for adhesives with good finishing properties, and an adhesive composition with excellent adhesive properties, good performance balance, and excellent solubility and coating properties. I will provide a. [Solution] The vinyl comprises at least two vinyl aromatic monomer unit polymer blocks (A) and a polymer block (B) mainly comprising at least one conjugated diene monomer unit. The vinyl aromatic monomer polymer block amount (% by mass) in the aromatic monomer unit polymer block (A) was used to polymerize the vinyl aromatic monomer unit polymer block (A). A block copolymer component (a) having a specific structure comprising 95.0 to 99.0% of the total vinyl aromatic monomer unit amount (% by mass) and comprising the polymer blocks A and B ) To (d) are selectively contained in a block copolymer for adhesives.

Description

  The present invention relates to a block copolymer for adhesives, a method for producing the same, and 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 Literature 1 and Patent Literature 2 disclose an adhesive composition or an adhesive composition using SBS. However, since the adhesive composition or adhesive composition using SBS or SIS has an insufficient adhesive / adhesive property balance of adhesive strength, tack, and holding power, there is no improvement in these performance aspects. As these improvement methods, Patent Document 3 and Non-Patent Document 1 disclose an adhesive composition containing a triblock copolymer and a diblock copolymer.
However, in any of the above-mentioned pressure-sensitive adhesive composition and adhesive composition, the above-described various performance improvement effects are insufficient.
In response to such a demand for improvement, Patent Documents 4 and 5 include a block copolymer obtained by coupling with a specific bifunctional coupling agent (aliphatic monoester or specific dihalogen compound). An adhesive composition is disclosed.

Japanese Examined Patent Publication No. 44-17037 Japanese Patent Publication No.56-49958 JP 61-278578 A JP-A-61-261310 JP-A-3-285978

Ishii, Ichiro, “Quality Design of SIS-Based Adhesives”, Adhesion, Polymer Press, January 25, 1988, Vol. 32, No. 1, pp. 27-28

However, the composition for pressure-sensitive adhesives disclosed in Patent Documents 4 and 5 needs to be further improved from the viewpoints of solubility and coating properties in addition to the balance between holding power and adhesiveness. .
Therefore, in the present invention, in view of the above-mentioned problems of the prior art, a block copolymer excellent in finish, that is, easy to handle and excellent in workability, and a good balance of properties such as adhesive strength and holding power Furthermore, it aims at providing the adhesive composition which is excellent also in solubility and coating property.

As a result of intensive studies in order to solve the above-described problems of the prior art, the inventors of the present invention have developed a block copolymer for adhesives that combines a block copolymer having a specific structure, and the block copolymer. The present inventors have found that an adhesive composition using a coalescence effectively solves the above problems, and has completed the present invention.
That is, the present invention is as follows.

[1]
A block copolymer comprising at least two vinyl aromatic monomer unit polymer blocks (A) and a polymer block (B) mainly composed of at least one conjugated diene monomer unit; A block copolymer for adhesives,
The amount of vinyl aromatic monomer polymer block (% by mass) in the vinyl aromatic monomer unit polymer block (A) polymerizes the vinyl aromatic monomer unit polymer block (A). 95.0-99.0% with respect to the total vinyl aromatic monomer unit amount (mass%) used,
And,
The block for adhesives which consists of 20-50 mass% of at least any one component chosen from the group which consists of the following component (a) 50-80 mass% and the following component (b), (c), and (d). Copolymer.
(A): A diblock copolymer having a number average molecular weight of 20,000 to 80,000, represented by the general formula (AB).
(B): a block copolymer having a number average molecular weight of 40,000 to 160,000, wherein _n is an integer of 2 or more and (AB) is represented by _n .
(C): a block copolymer having a number average molecular weight of 40,000 to 160,000, wherein _p is an integer of 1 or more and is represented by (AB) pA.
(D): A branched block copolymer having a number average molecular weight of 40,000 to 160,000, wherein m is any one of 2, 3, and 4 and is represented by general formula (AB) _m X. X represents a residue of a coupling agent or a residue of a polymerization initiator.
[2]
(I) The block copolymer for adhesives according to [1]: 100 parts by mass;
(Ii) Tackifier: 100 to 400 parts by mass;
(Iii) softening agent: 50 to 150 parts by mass;
An adhesive composition containing
[3]
The adhesive composition according to [2], which satisfies the following requirements (1) to (3).
(1): Loop tack T (N / 15 mm) / 50 is 0.8 or more (2): 180 ° peeling adhesive strength P (N /) measured according to the measuring method of peeling strength of JIS Z0237 10 mm) / 30 is 0.8 or more (3): Holding force C (minute) / 10 is 0.8 or more [4]
A method for producing a block copolymer for adhesives according to [1] above,
A step of polymerizing a vinyl aromatic monomer unit to produce the vinyl aromatic monomer unit polymer block (A);
4 minutes or more from the time when the conjugated diene monomer unit reaches the maximum temperature in the step of producing the vinyl aromatic monomer unit polymer block (A) by polymerizing the vinyl aromatic monomer unit. A step of adding at a time when less than a minute has elapsed and when the temperature has decreased by 1.5 ° C. or more from the maximum temperature;
The manufacturing method of the block copolymer for adhesives which has this.
[5]
It is a manufacturing method of the block copolymer for adhesives as described in said [1] containing the said component (c),
After the step of polymerizing the vinyl aromatic monomer unit to produce the vinyl aromatic monomer unit polymer block (A), a deactivator for terminating the polymerization of the block copolymer, the step The block copolymer for adhesives according to [4], which is added when 4 to 20 minutes have elapsed from the time when the maximum temperature is reached and the temperature falls 1.5 ° C. or more from the maximum temperature. Method.

  According to the present invention, the block copolymer for adhesives excellent in finishing properties, and excellent adhesive properties such as adhesive strength and holding power, and the property balance is also good, and further excellent dissolution The adhesive composition having properties and coating properties can be provided.

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.

[Block copolymer for adhesives]
(Construction)
The block copolymer for adhesives of this embodiment has at least two vinyl aromatic monomer unit polymer blocks (A): (hereinafter sometimes referred to as polymer block A or A). And a polymer block (B) mainly composed of at least one conjugated diene monomer unit (hereinafter also referred to as polymer block B or B). Including.
“Mainly” means that the conjugated diene monomer unit is contained in an amount of 50% by mass or more, preferably 70% by mass or more, more preferably 85% by mass or more. The polymer block (B) in the block is a copolymer block of a conjugated diene compound and a vinyl aromatic hydrocarbon and / or a conjugated diene homopolymer block.
The block copolymer for an adhesive of this embodiment is a vinyl aromatic monomer block amount (% by mass) in the vinyl aromatic monomer unit polymer block (A), that is, a vinyl aromatic monomer. The body block ratio is 95.0 to 99.0% based on the total vinyl aromatic monomer unit amount (% by mass) used for polymerizing the vinyl aromatic monomer unit polymer block (A). is there.
Moreover, the block copolymer for adhesives of this embodiment is at least selected from the group consisting of the following component (a) 50 to 80% by mass and the following components (b), (c), and (d). It consists of 20-50 mass% of any one component.
(A): A diblock copolymer having a number average molecular weight of 20,000 to 80,000, represented by the general formula (AB).
(B): a block copolymer having a number average molecular weight of 40,000 to 160,000, wherein _n is an integer of 2 or more and (AB) is represented by _n .
(C): a block copolymer having a number average molecular weight of 40,000 to 160,000, wherein _p is an integer of 1 or more and is represented by (AB) pA.
(D): A branched block copolymer having a number average molecular weight of 40,000 to 160,000, wherein m is any one of 2, 3, and 4 and is represented by general formula (AB) _m X. X represents a residue of a coupling agent or a residue of a polymerization initiator.
The number average molecular weights of the components (a) to (d) can be measured by the method described in Examples described later.
When the number average molecular weight of the components (a) to (d) is in the above range, the adhesive composition of the present embodiment described later has excellent adhesiveness, adhesive strength, holding power, solubility, and coating. Sex is obtained.
About the range of a preferable number average molecular weight, the block copolymer of the said component (a) is 40,000-70,000, More preferably, it is 45,000-65,000, The said component (b), ( The block copolymer of c) and (d) is 80,000 to 140,000, more preferably 90,000 to 130,000.

  The combinations of the components (a) to (d) are as follows: component (a) + component (b), component (a) + component (c), component (a) + component (d), component (a) + component ( b) + component (c), component (a) + component (b) + component (d), component (a) + component (c) + component (d), component (a) + component (b) + component ( c) any one of the components (d).

As described above, the ratio of the mass of the vinyl aromatic monomer polymer block to the total mass of all vinyl aromatic monomer units used to polymerize the vinyl aromatic monomer unit polymer block (A), That is, the block rate is 95.0 to 99.0%. In the block copolymer for adhesives of this embodiment, the block rate is preferably 97.0 to 99.0%, more preferably 97.5 to 98.5%.
When the block ratio is in the numerical range, the block copolymer for an adhesive of the present embodiment is isolated, that is, the fusion process does not occur in the finishing step, and the drying process can be performed smoothly. A high yield will be obtained. Moreover, when coloring of the block copolymer for adhesives is considered, it is preferable that it is 99.0% or less.
The block ratio of the vinyl aromatic monomer unit polymer block (A) is such that when the vinyl aromatic monomer is styrene, the vinyl aromatic in the vinyl aromatic monomer unit polymer block (A) Block ratio of monomer polymer block = Styrene block content (mass%) / styrene content (mass%) × 100.
In the block copolymer for adhesive of this embodiment, the vinyl aromatic monomer unit, for example, in the above example, the content of styrene is not particularly limited, but the adhesive of this embodiment described later is used. It is preferably 10 to 60% by mass, more preferably 20 to 50% by mass from the viewpoint of the balance of adhesive properties (adhesiveness (loop tack), adhesive strength, and holding power) in the agent composition. is there.
When the content of the vinyl aromatic monomer unit is 10% by mass or more, excellent tackiness and holding power are obtained in the adhesive composition of the present embodiment described later, and the content is 60% by mass or less. Excellent adhesive strength can be obtained.

Next, the block copolymer (component (a)-(d)) which is a structural component of the block copolymer for adhesives of this embodiment is demonstrated.
Components (a) to (d) are block copolymers comprising a vinyl aromatic monomer unit polymer block (A) and a polymer block (B) mainly composed of a conjugated diene monomer unit. The structure and the number average molecular weight are as described above.
Examples of the vinyl aromatic hydrocarbon constituting the components (a) to (d) include alkyl styrene such as styrene, α-methyl styrene, p-methyl styrene and p-tert-butyl styrene, paramethoxy styrene, vinyl. And naphthalene. Styrene is preferred as the vinyl aromatic hydrocarbon.
The conjugated diene compound constituting the components (a) to (d) is a diolefin having a conjugated double bond, such as 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. 1 type may be sufficient as a conjugated diene compound, and 2 or more types may be sufficient as it.

Moreover, the vinyl bond content of the conjugated diene moiety in the block copolymer for adhesives of this embodiment is preferably less than 20%.
When the vinyl bond content of the conjugated diene moiety is less than 20%, characteristics excellent in thermal stability and weather resistance can be obtained. On the other hand, from the viewpoint of heat resistance (heat distortion temperature), the vinyl bond content is preferably 8% or more.
The amount of vinyl bonds can be measured by, for example, a nuclear magnetic resonance apparatus (manufactured by BRUKER, DPX-400) or an infrared spectrophotometer (device name: FT / IR-230; manufactured by JASCO Corporation) by the Hampton method. Can be calculated.
In order to adjust the vinyl bond amount of the conjugated diene moiety in the block copolymer, for example, ethers and tertiary amines, specifically, ethylene glycol dimethyl ether, tetrahydrofuran, α-methoxytetrahydrofuran, N, N , N ′, N′-Tetramethylethylenediamine and the like, and it is preferable to use a regulator composed of one or a mixture of two or more.
Specifically, the vinyl bond amount of the conjugated diene moiety in the block copolymer is, for example, ethers or tertiary amines, such as ethylene glycol dimethyl ether, tetrahydrofuran, α-methoxytetrahydrofuran, N, Adjustment is carried out by adding a regulator comprising one or a mixture of two or more selected from N, N ′, N′-tetramethylethylenediamine and the like into the polymerization solvent in the previous stage of adding the conjugated diene monomer. can do.

[Method for producing block copolymer for adhesive]
The block copolymer for an adhesive of this embodiment is obtained by polymerizing a vinyl aromatic hydrocarbon such as styrene in an inert hydrocarbon solvent using an organolithium compound as a polymerization initiator, and then conjugated diene. It can be obtained by a method of polymerizing a compound, for example, butadiene, and further repeating these operations in some cases, or a method of separately polymerizing and mixing, for example, styrene butadiene block copolymer: components (a) to (d). Moreover, when producing the mixture of the arbitrary ratios of a component (a) and a component (d), it can manufacture by controlling the addition amount of a coupling agent.
The molecular weights of the components (a) to (d) can be adjusted to the predetermined range by controlling the amount of the organic lithium compound that is a polymerization initiator.
After completion of the polymerization reaction, the active species are deactivated by adding water, alcohol, acid, etc., and the solution is subjected to, for example, steam stripping, etc. to separate the polymerization solvent, and then dried to dry the block for the adhesive. A polymer is obtained.

Although it does not specifically limit as a polymerization method of the block copolymer of said component (a)-(d), Polymerization methods, such as coordination polymerization, anionic polymerization, or cationic polymerization, are mentioned. Anionic polymerization is preferable from the viewpoint of easy control of the structure.
As a method for producing a block copolymer component by anionic polymerization, a known method can be used. For example, Japanese Patent Publication No. 36-19286, Japanese Patent Publication No. 43-1779, Japanese Patent Publication No. 46-32415, JP-B-49-36975, JP-B-48-2423, JP-B-48-4106, JP-B-56-28925, JP-A-59-166518, JP-A-60-186777, etc. The methods described are mentioned.

Examples of the inert hydrocarbon solvent used in the polymerization step of components (a) to (d) include aliphatic hydrocarbons such as butane, pentane, hexane, isopentane, heptane, octane and isooctane; cyclopentane and methylcyclopentane. And alicyclic hydrocarbons such as cyclohexane, methylcyclohexane and ethylcyclohexane; hydrocarbon solvents such as aromatic hydrocarbons such as benzene, toluene, ethylbenzene and xylene. These may use only 1 type and may mix and use 2 or more types.
In addition, as the organic lithium compound used in the polymerization step of components (a) to (d), known compounds such as ethyl lithium, propyl lithium, n-butyl lithium, sec-butyl lithium, tert-butyl lithium, phenyl Examples thereof include lithium, propenyl lithium, hexyl lithium and the like. In particular, n-butyl lithium and sec-butyl lithium are preferable. Only one type of organic lithium compound may be used, or a mixture of two or more types may be used.
In the block copolymer components (a) to (d), part or all of the unsaturated double bonds derived from the conjugated diene may be hydrogenated. The hydrogenation method is not particularly limited, and is performed using a known technique.

The block copolymer (a): general formula: (AB) can be polymerized by the method described above.
As described above, A is a vinyl aromatic monomer unit polymer block, and B is a polymer block mainly composed of a conjugated diene monomer unit.

Moreover, block copolymer (b): General formula: (AB) _n can be superposed | polymerized by the method mentioned above.
As described above, A is a vinyl aromatic monomer unit polymer block, and B is a polymer block mainly composed of a conjugated diene monomer unit. n is an integer of 2 or more.

Further, the block copolymer (c): general formula: (AB) _p A can be polymerized by the method described above.
As described above, A is a vinyl aromatic monomer unit polymer block, and B is a polymer block mainly composed of a conjugated diene monomer unit. p is an integer of 1 or more.

Furthermore, the block copolymer (d): general formula: (AB) _m X can be polymerized by the method described above.
As described above, A is a vinyl aromatic monomer unit polymer block, and B is a polymer block mainly composed of a conjugated diene monomer unit.
X represents the residue of each coupling agent or the residue of an initiator such as each functional 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 in the general formula of the target block copolymer (d).
That is, among the coupling agents, any known bifunctional coupling agent can be used and is not particularly limited. For example, epoxy compounds; silicon halide 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; and vinyl allenes such as divinylbenzene.
As the trifunctional coupling agent, any known one can be used and is not particularly limited. For example, tin compounds such as methyl tin trichloride and tributyl chloro tin; silane compounds such as trimethoxy silane and triethoxy silane; silicon halide compounds such as methyl silicon trichloride and trimethyl chloro silicon, and the like.
Any known tetrafunctional coupling agent can be used and is not particularly limited. For example, tin halide compounds such as tin tetrachloride; allyltin compounds such as tetraallyltin and tetra (2-octenyl) tin; tin compounds such as tetraphenyltin and tetrabenzyltin; silicon tetrachloride and tetrabromide Examples include silicon halide compounds such as silicon; alkoxysilicon compounds such as tetraphenoxysilicon and tetraethoxysilicon.

The method of mixing each block copolymer (a) to (d) is a method of mixing the solution after the completion of polymerization, or a method of blending each block copolymer component obtained by drying with a roll or the like. Can be mentioned.
Further, when obtaining a mixture of the block copolymers (a) and (d), the block copolymer weight is controlled by controlling the coupling rate in producing the block copolymer (d) as described above. A mixture in any proportion with the union (a) is obtained.
The mixing ratio of each component in the block copolymer is at least one component selected from the group consisting of 50 to 80% by mass of component (a), components (b), (c), and (d). It is a ratio of ˜50 mass%.
A preferable mixing ratio of each component is that component (a) is 55 to 75% by mass, and at least one component selected from the group consisting of components (b), (c), and (d) is 25 to 45% by mass. The mixing ratio of each component is more preferably 60 to 70% by mass of component (a), and 30 to 40% by mass of at least one component selected from the group consisting of components (b), (c), and (d). It is.
Thereby, in the adhesive composition of this embodiment mentioned later, the outstanding adhesiveness, adhesive force, holding power, solubility, and coating property are obtained. In particular, since the solubility is good, the heating and mixing time can be shortened, and discoloration due to thermal deterioration can be prevented.

As described above, the block copolymer for adhesives of this embodiment contains at least two vinyl aromatic monomer unit polymer blocks (A), and the vinyl aromatic monomer. The unit polymer block (A) is a vinyl aromatic monomer weight based on the total vinyl aromatic monomer unit amount (% by mass) used for polymerizing the vinyl aromatic monomer unit polymer block (A). The combined block amount (% by mass), that is, the block ratio is 95 to 99%.
In order to obtain the vinyl aromatic monomer unit polymer block (A) having a block ratio of 95 to 99%, the timing and block at which the vinyl aromatic monomer unit is polymerized and the conjugated diene monomer unit is added What is necessary is just to select the timing which complete | finishes superposition | polymerization of a copolymer. Generally, the time at which the monomer is almost completely polymerized is considered to be about 10 minutes after the peak temperature that appears at the end of the polymerization is reached, and the next monomer is added. Alternatively, a deactivator for terminating the polymerization is added.
In the block copolymer of this embodiment, the timing of adding the conjugated diene monomer unit or the timing of terminating the polymerization of the block copolymer is the polymerization process of the vinyl aromatic monomer unit polymer block (A). 4-20 minutes after reaching the peak temperature at the end of the polymerization of the vinyl aromatic monomer unit, preferably after 5-15 minutes, and from the peak temperature After lowering by 1.5 ° C. or more, preferably 3 ° C. or more.
A vinyl aromatic monomer unit polymer having a block ratio of 95.0 to 99.0% when the elapsed time from reaching the peak temperature is less than 4 minutes and the decrease temperature from the peak temperature is less than 1.5 ° C. There arises a problem that the block (A) cannot be obtained.

In addition, when adding a deactivator to complete the polymerization of the block copolymer, the timing of adding the deactivator is the time of completion of the polymerization of the vinyl aromatic monomer unit, that is, the vinyl aromatic monomer unit. 4 to 20 minutes, preferably 5 to 15 minutes, more preferably 5 to 12 minutes from the time when the peak temperature appears at the end of the polymerization step of the polymer block (A), and the peak The temperature is lowered by 1.5 ° C. or more, preferably 3 ° C. or more, more preferably 3.5 ° C. or more than the temperature.
If the quenching agent is added after the elapsed time from the peak temperature is less than 4 minutes, a sufficient block rate cannot be obtained, which is not preferable. In addition, when the elapsed time from reaching the peak temperature is 20 minutes or more, the block rate increases, but the living end is deactivated, and the tape performance of the obtained adhesive composition containing the block copolymer is Each characteristic balance of a certain loop tack, adhesive strength and holding power is inferior. Further, the obtained block copolymer is not preferable because it is colored.
In addition, the addition timing of the deactivator for terminating the polymerization is appropriately selected depending on the structure of the block copolymer. That is, in the case of component (c), it is after the addition of the vinyl aromatic monomer unit, and in the case of components (a), (b) and (d), it is after the addition of the conjugated diene monomer unit.

  In the manufacturing method of the block copolymer for adhesives of this embodiment, the process of deashing the metal originating in a polymerization initiator etc. can be employ | adopted as needed. Moreover, you may employ | adopt the process of adding reaction terminator, antioxidant, neutralizing agent, surfactant, etc. as needed.

  The block copolymer for adhesives of this embodiment that can be produced as described above is a so-called modified product in which a functional group containing a polar group selected from nitrogen, oxygen, silicon, phosphorus, sulfur, and tin is bonded to the polymer. It may be a modified block copolymer obtained by modifying a polymer or a block copolymer component with a modifying agent such as maleic anhydride, and can be obtained by performing a known modification reaction.

After the block copolymers of the components (a) to (d) constituting the block copolymer for an adhesive according to this embodiment are produced as described above, the block polymer is isolated by the method described later. That is, finish.
The polymerization step of the block copolymers (a) to (d) is performed in an inert hydrocarbon solvent as described above. Therefore, in order to isolate the block copolymer, it is necessary to remove the solvent.
Specific methods for removing the solvent include a method of obtaining a water-containing crumb by steam stripping and obtaining a block copolymer by drying the obtained water-containing crumb.
A preferred embodiment for removing the solvent by steam stripping generally uses a surfactant as a crumbing agent during steam stripping, and examples of such surfactants include anionic surfactants. , Cationic surfactants and nonionic surfactants. These surfactants are generally added in an amount of 0.1 to 3000 ppm with respect to the water in the stripping zone.
In addition to the surfactant, a water-soluble salt of a metal such as Li, Na, Mg, Ca, Al, and Zn can be used as a dispersion aid for crumb.
The concentration of the crumb-like block copolymer dispersed in water obtained through the polymerization step of the block copolymer and the steam stripping is generally 0.1 to 20% by mass (ratio of stripping zone to water). In this range, a crumb having a good particle size can be obtained without causing any trouble in operation. The moisture content of the block copolymer crumb obtained above is adjusted by dehydration to a water content of 1 to 30% by mass, and then dried until the water content becomes 1% by mass or less.
In the crumb dehydration step, dehydration with a compressed water squeezer such as a roll, Banbury dehydrator, screw extruder squeeze dehydrator, or simultaneous dehydration and drying with a conveyor or box-type hot air dryer may be performed. Good.
If the block ratio of the block A constituting the block copolymer for an adhesive of the present embodiment is in the range of 95.0 to 99.0%, the block copolymer is not fused and drying can be performed smoothly. When the block ratio is less than 95.0%, the block copolymers are fused to each other and tend to adhere to the conveyor surface or adhere to the wall surface of the box-type dryer.

[Adhesive composition]
(Constitution)
The adhesive composition of this embodiment contains the above-mentioned (i) block copolymer for adhesives, (ii) a tackifier described later, and (iii) a softener described later. And contains other components as described below as required.
In addition, according to a use, it is preferable to select the number average molecular weight of component (a)-(d) in a block copolymer, and to prepare each compounding quantity of a tackifier and a softener.
The adhesive composition of the present embodiment includes (i) the block copolymer for adhesives: 100 parts by mass, and (ii) the tackifier: 100 to 400 parts by mass of the above-described embodiment. (Iii) Softener: It is preferable to contain 50 to 150 parts by mass.
Thereby, in the adhesive composition of this embodiment, the outstanding adhesiveness, adhesive force, holding power, solubility, and coating property are obtained.
In the above-mentioned adhesive composition, the amount of (ii) tackifier is more preferably 150 to 400 parts by mass, further preferably 200 to 400 parts by mass. Moreover, the amount of the more preferable (iii) softening agent is 70-130 mass parts.

(Tackifier)
The tackifier which comprises the adhesive composition of this embodiment can be selected variously according to the use and required performance of the obtained adhesive composition.
For example, coumarone resin, aromatic hydrocarbon resin, rosin resin, terpene resin, petroleum resin, phenol resin, terpene-phenol resin, alicyclic hydrocarbon resin, hydrogenated terpene resin, hydrogenated Known tackifier resins such as rosin resins can be used.
These tackifier resins may be used alone or in combination of two or more.

(Softener)
The softening agent 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.

(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 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] -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)] acrylate, etc. NOL antioxidants; sulfur antioxidants such as dilauryl thiodipropionate, lauryl stearyl thiodipropionate pentaerythritol-tetrakis (β-lauryl thiopropionate); tris (nonylphenyl) phosphite, tris ( And phosphorus-based antioxidants such as 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 2- (2′-hydroxy-5′-methylphenyl) benzotriazole, 2- (2′-hydroxy-3 ′, 5′-t-butylphenyl) benzotriazole, 2- ( Benzotriazole ultraviolet absorbers such as 2′-hydroxy-3 ′, 5′-di-t-butylphenyl) -5-chlorobenzotriazole, benzophenone ultraviolet absorbers such as 2-hydroxy-4-methoxybenzophenone, Or a hindered amine light stabilizer etc. can be mentioned.

  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.

(Characteristic)
As for the performance of the pressure-sensitive adhesive tape obtained from the adhesive composition of this embodiment, loop tack T: (N / 15 mm) / 50 is 0.8 or more, and pressure-sensitive adhesive force P: (N / 10 mm) / 10 is 0.00. It is preferable that the holding power C: (min) / 10 is 8 or more. The numerical value of each item is more preferably 0.9 or more, and further preferably 0.95 or more.
The performance of the pressure-sensitive adhesive tape obtained from the adhesive composition of the present embodiment can be measured according to the measurement conditions shown in the examples, using pressure-sensitive adhesive tapes produced under the conditions shown in the examples described later. it can.

[Method for producing adhesive composition]
The adhesive composition of the present embodiment can be produced by mixing the block copolymer described above, a tackifier, and a softener by a known method.
Examples of the mixing method include a method in which a block copolymer, a tackifier, and a softener are uniformly mixed under a heating condition using a mixer, a kneader, or the like.
The temperature in the mixing step is preferably 130 ° C to 210 ° C. If it is less than 130 degreeC, a block copolymer may not fully melt | dissolve and there exists a possibility of causing a dispersion | distribution defect. Moreover, when it exceeds 210 degreeC, there exists a possibility that adhesive property may cause deterioration by bridge | crosslinking of a block copolymer, evaporation of the low molecular weight component of a tackifier, etc. A preferable mixing temperature is 140 ° C to 200 ° C, more preferably 150 ° C to 190 ° C.
The mixing time is preferably 5 to 90 minutes. If it is less than 5 minutes, the components may not be uniformly dispersed. Moreover, when it exceeds 90 minutes, there exists a possibility of causing deterioration of an adhesive property by bridge | crosslinking of a block copolymer, evaporation of the low molecular weight component of a tackifier, etc. A preferable mixing time is 10 minutes to 80 minutes, and more preferably 20 minutes to 70 minutes.
As the tackifier, aliphatic cyclic hydrocarbon resins (for example, Arakawa Chemical Industry Co., Ltd .: Archon M100), polyterpene resins (for example, Yashara Chemical Co., Ltd .: Clearon M115) and the like can be preferably 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.
The adhesive composition of the present embodiment has a loop tack T: (N / 15 mm) / 50 of 0.8 or more, an adhesive strength P: (N / 10 mm) / 10 of 0.8 or more, Holding power: C (min) / 10 is 0.8 or more. The loop tack, adhesive force and holding force can be measured by the methods described in the examples described later.
The loop tack can be improved by increasing the amount of the softener component used. In addition, when the usage-amount of a softening agent component is increased, the fall of holding power will be caused, Therefore A compounding ratio is adjusted according to a desired characteristic.
The adhesive strength can be improved by increasing the amount of the tackifier used. In addition, when the usage-amount of a tackifier is increased, since a loop tack and a holding power fall will be caused, a compounding ratio is adjusted according to a desired characteristic.
The holding power can be improved by increasing the amount of the block copolymer used. In addition, when the usage-amount of a block copolymer is increased, the fall tackiness will be lowered | hung or the melt viscosity of the adhesive composition of this embodiment will become high, and workability (solubility, coating property). Therefore, the blending ratio is adjusted according to the desired characteristics.

[Use]
The adhesive composition of this embodiment has good solubility and coating properties, is excellent in adhesiveness, adhesive strength, and holding power, and also has a good balance of adhesive properties. 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 can be used for adhesives and the like, and is particularly useful for adhesive tapes, adhesive sheets and films, adhesive labels, surface protection sheets and films, and hygiene adhesives.

  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.
[(I) Properties of block copolymer]
<(I-1) Finishing property of block copolymer>
The solvent is removed by steam stripping the polymerization solution, then the hydrated crumb is sent to a single screw extruder water squeezer, and the dehydrated crumb (block copolymer) is dried in a box-shaped hot air at 85 ° C. The adhesion state of the block copolymer after drying for 1 hour with a machine and the inner wall of the box of the hot air dryer was observed.
As the standard of finish, in order from the better evaluation, the block copolymer is not adhered to the inner wall of the box at all, ○ is slightly adhered, but those that peel off naturally are Δ to ○, slightly Although it was observed that the film was easily peeled by hand, the block copolymer was firmly adhered to the inner wall of the box, and the state that could not be peeled off unless a considerably strong force was applied was evaluated as x.

<(I-2) Styrene content>
A certain amount of block copolymer was dissolved in chloroform, measured with an ultraviolet spectrophotometer (manufactured by Shimadzu Corporation, UV-2450), and using a calibration curve from the peak intensity of the absorption wavelength (262 nm) caused by the styrene component. The styrene content was calculated.

<(I-3) Styrene block content>
About 0.07 g of block copolymer is precisely weighed and dissolved in 10 mL of chloroform, and 20 mL of a solution of osmium acid / tertiary butyl hydroperoxide (concentration: 0.1 g / 33 mL) is added to the chloroform solution. The mixture was refluxed in a hot water bath at 90 to 95 ° C. for 15 minutes to break the double bond of the butadiene component.
Methanol was added to precipitate undecomposed components, followed by filtration using a glass filter, and the filtrate was dissolved in chloroform.
The obtained solution was measured with an ultraviolet spectrophotometer (manufactured by Shimadzu Corporation, UV-2450), and the styrene block content was calculated from the peak intensity of the absorption wavelength (262 nm) caused by the styrene component using a calibration curve.

<(I-4) 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 number 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).

<(I-5) Vinyl bond content of 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)”).

[(II) Measurement of physical properties of adhesive composition]
<Solubility of (II-1) Adhesive Composition>
The change in torque of a pressure kneader (D0.3-3 type kneader manufactured by Moriyama Seisakusho Co., Ltd.) used as a mixing device was read, and the time when the rate of change was within 1% was taken as the dissolution time.
The criteria for determining solubility were evaluated in the order of better evaluation, with the dissolution time being within 40 minutes as ◯, 40 to 60 minutes as Δ, and 60 minutes or more as x.

<(II-2) 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 180 ° C.

<Softening point of (II-3) 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.

<(II-4) Coating property>
The melted adhesive composition was hung on a hot plate heated to 160 ° C., and the adhesive application surface after coating with an applicator heated to 160 ° C. was visually observed.
Criteria for coating properties are, in order from the highest evaluation, ◯ when there is no unevenness, △ to ○ when unevenness is less than 20%, Δ when unevenness is 20% or more and less than 50%, and 50% unevenness. The above was evaluated as x.

The molten adhesive composition is cooled to room temperature, dissolved in toluene, coated on a polyester film with an applicator, and then the toluene is completely evaporated for 30 minutes at room temperature and 7 minutes in an oven at 70 ° C. An adhesive tape having a thickness of 50 μm was prepared.
The tackiness (loop tack), tackiness and holding strength of the adhesive composition were measured by the following methods.
<(II-5) Adhesiveness (loop tack)>
Using a loop-shaped sample of 250 mm length × 15 mm width, measurement was performed at a contact area with a PE (polyethylene) plate: 15 mm × 50 mm, an adhesion time of 3 sec, and an adhesion and peeling speed: 500 mm / min.
The measured value T (N / 15 mm) / 50 was taken as a score, and if it was 1.0 or more, it was judged that the performance was practically excellent, and if it was 0.8 or more, it was judged to be practically sufficient performance.
<(II-6) Adhesive strength>
JIS Z0237 peel adhesion measurement method 1: According to the measurement method of 180 ° peel adhesion to the test plate, a 25 mm wide sample was attached to a polyethylene plate, and the 180 ° adhesion at a peeling speed of 300 mm / min. The force was measured.
The measured value P (N / 10 mm) / 30 was scored, and if it was 1.0 or more, it was judged that the performance was practically excellent, and if it was 0.8 or more, it was judged that the performance was practically sufficient.
<(II-7) Holding power>
The holding force was measured by sticking the adhesive tape sample so that an area of 25 mm × 25 mm was in contact with the stainless steel plate and the PE plate, applying a load of 1 kg at 60 ° C., and measuring the time until the adhesive tape slipped.
The measured value C (min) / 10 was scored, and if it was 1.0 or more, it was judged that the performance was practically excellent, and if it was 0.8 or more, it was judged that the performance was practically sufficient.

  In addition, it was judged that the one where the total point of the said adhesiveness, adhesive force, and holding power is higher is excellent in the performance balance as an adhesive composition.

[(III) Preparation of block copolymer component]
<Polymer 1: Bifunctional coupling styrene-butadiene block copolymer>
A stainless steel autoclave with a stirrer and a jacket with an internal volume of 10 L was washed, dried and purged with nitrogen, charged with 5720 g of cyclohexane and 280 g of pre-purified styrene, and warm water was passed through the jacket to set the contents at about 40 ° C. .
Next, n-butyllithium cyclohexane solution (1.5 g in pure content) was added to initiate polymerization of styrene.
6 minutes after reaching the maximum temperature (53 ° C.) due to the polymerization of styrene, 2 ° C. lower than the maximum temperature, 520 g of butadiene (1,3-butadiene) was added and the polymerization was continued. 30 seconds after the polymerization to reach the maximum temperature (89 ° 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 parts by mass of octadecyl-3- (3,5-dibutyl-t-butyl-4-hydroxyphenyl) propionate is added with respect to 100 parts by mass of the block copolymer. And mixed well. In steam stripping the above polymerization solution, a mixture of α- (p-nonylphenyl) -ω-hydroxypoly (oxyethylene) dihydrodiene phosphate ester and monohydrodiene phosphate ester as a crumbing agent Was used at 30 ppm with respect to the water in the stripping zone, and the solvent was removed at a temperature of 90 to 98 ° C.
The concentration of the polymer crumb in the slurry in the solvent removal tank was about 5% by mass.
Subsequently, the water dispersion slurry of the crumb block copolymer obtained above was sent to a rotary screen to obtain a water-containing crumb having a water content of 45% by mass. This hydrous crumb was sent to a single screw extruder water squeezer to obtain a dehydrated polymer. This crumb was dried with a box-type hot air dryer at 85 ° C. for 1 hour (the obtained block copolymer is referred to as polymer 1). The obtained polymer 1 was colorless and transparent.
The polymer 1 has a styrene content of 35% by mass based on the whole polymer 1 used for polymerizing the vinyl aromatic monomer unit polymer block (A), and the vinyl aromatic monomer unit polymer block The styrene block content (% by mass) in (A) is based on the total amount of styrene monomer units (% by mass) used for polymerizing the vinyl aromatic monomer unit polymer block (A). The number average molecular weight of component (a) was 63,000, and the number average molecular weight of component (d) was 120,000.
Further, 70% by mass of a block copolymer having a diblock structure of styrene-butadiene, which is a component (a) equivalent product, was contained. The vinyl bond content in the butadiene portion was 12.5%.
Polymer 1 was a mixture of component (d): ((AB) _m X) = 2 and components (a) :( AB).

<Polymer 2: Trifunctional coupling styrene-butadiene block copolymer>
A stainless steel autoclave with a stirrer and a jacket with an internal volume of 10 L was washed, dried, purged with nitrogen, charged with 5720 g of cyclohexane and 240 g of pre-purified styrene, and warm water was passed through the jacket to set the contents at about 40 ° C. .
Next, n-butyllithium cyclohexane solution (1.4 g in pure content) was added to initiate polymerization of styrene.
5 minutes after reaching the maximum temperature (51 ° C.) due to the polymerization of styrene, 560 g of butadiene (1,3-butadiene) was added after the temperature decreased by 2 ° C. from the maximum temperature, and the polymerization was continued. 35 seconds after reaching the maximum temperature (91 ° C.) by polymerization, triethoxysilane 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 parts by mass of octadecyl-3- (3,5-dibutyl-t-butyl-4-hydroxyphenyl) propionate is added with respect to 100 parts by mass of the block copolymer. Then, similar to the above-described production process of polymer 1, the solution was subjected to steam stripping, the polymerization solvent was separated, and then dried (the obtained block copolymer is referred to as polymer 2). The obtained polymer 2 was colorless and transparent.
In the polymer 2, the content of styrene used for polymerizing the vinyl aromatic monomer unit polymer block (A) is 30% by mass with respect to the entire polymer 2, and the styrene block ratio is 95.8%. The number average molecular weight of component (a) was 38,000, and the number average molecular weight of component (d) was 112,000.
Moreover, the block copolymer of the diblock structure of styrene-butadiene contained 75 mass%. The vinyl bond content in the butadiene portion was 13.5%.
Polymer 2 was a mixture of component (d): ((AB) _m X) m = 3 and component (a) :( AB).

<Polymer 3: Mixture of styrene-butadiene block copolymer and styrene-butadiene-styrene block copolymer>
A stainless steel autoclave with an internal volume of 10 L equipped with a stirrer and a jacket was washed, dried and purged with nitrogen, charged with 5720 g of cyclohexane and 120 g of pre-purified styrene, and warm water was passed through the jacket to set the contents at 40 ° C.
Next, n-butyllithium cyclohexane solution (1.4 g in pure content) was added to initiate polymerization of styrene.
7 minutes after reaching the maximum temperature (50 ° C.) due to the polymerization of styrene, and after dropping 2.5 ° C. from the maximum temperature, 560 g of butadiene (1,3 butadiene) was added and the polymerization was continued. Fully polymerized, 40 seconds after reaching the maximum temperature (88 ° C.), 120 g of styrene was added again to continue the polymerization, and 8 minutes after reaching the maximum temperature (95 ° C.) by styrene polymerization. After the temperature decreased by 3 ° C. from the maximum temperature, 0.5 g of water was added to inactivate.
To the obtained block copolymer solution, 0.3 part by mass of octadecyl-3- (3,5-dibutyl-t-butyl-4-hydroxyphenyl) propionate was added to 100 parts by mass of the block copolymer. After mixing the polymer solution and the polymer (styrene-butadiene block copolymer) solution before coupling of polymer 1, the solution was subjected to steam stripping and the polymerization solvent was separated in the same manner as in the production process of polymer 1 described above. Thereafter, it was dried (the obtained copolymer is referred to as polymer 3). The obtained polymer 3 was colorless and transparent.
In the polymer 3, the content of styrene used for polymerizing the vinyl aromatic monomer unit polymer block (A) was 33.5% by mass with respect to the whole polymer 3, and the styrene block ratio was 97. The number average molecular weight of component (a) was 63,000, and the number average molecular weight of component (c) was 120,000. The vinyl bond content in the butadiene portion was 12.8%.
Polymer 3 was a mixture of component (a) :( AB) and component (c): ((AB) _p A) with p = 1.

<Polymer 4: Mixture of styrene-butadiene block copolymer and styrene-butadiene-styrene-butadiene block copolymer>
A stainless steel autoclave with an internal volume of 10 L equipped with a stirrer and a jacket was washed, dried and purged with nitrogen, charged with 5720 g of cyclohexane and 120 g of pre-purified styrene, and warm water was passed through the jacket to set the contents at 40 ° C.
Next, an n-butyllithium cyclohexane solution (1.35 g in pure content) was added to initiate styrene polymerization.
6 minutes after reaching the maximum temperature (51 ° C.) due to the polymerization of styrene, 2 ° C. lower than the maximum temperature, 520 g of butadiene (1,3 butadiene) was added, the polymerization was continued, and the butadiene was almost completely 40 seconds after the polymerization reaches the maximum temperature (86 ° C.), 120 g of styrene is added again to continue the polymerization, and 7 minutes after the maximum temperature (93 ° C.) is reached by polymerization of styrene, Then, 40 g of butadiene (1,3 butadiene) was added, and the polymerization was continued. After the butadiene was almost completely polymerized and reached the maximum temperature (97 ° C.), the temperature decreased by 3 ° C. from the maximum temperature after 50 seconds. .5 g was added for inactivation.
To the obtained block copolymer solution, 0.3 part by mass of octadecyl-3- (3,5-dibutyl-t-butyl-4-hydroxyphenyl) propionate was added to 100 parts by mass of the block copolymer. After mixing the polymer solution (polymer conversion: 35% by mass) and the polymer (styrene-butadiene block copolymer) solution (polymer conversion: 65% by mass) before the coupling of the above-described polymer 1, the above-described polymer 1 The solution was subjected to steam stripping to separate the polymerization solvent, and then dried (the resulting copolymer is referred to as polymer 4). The obtained polymer 4 was colorless and transparent.
In the polymer 4, the content of styrene used for polymerizing the vinyl aromatic monomer unit polymer block (A) was 33.25% by mass with respect to the whole polymer 4, and the styrene block ratio was 97. The number average molecular weight of component (a) was 63,000, and the number average molecular weight of component (c) was 140,000. The vinyl bond content of the butadiene portion was 12.5%.
Polymer 4 was an n = 2 mixture of component (a) :( AB) and component (b): ((AB) _n ).

<Polymer 5: Bifunctional coupling styrene-butadiene block copolymer>
Due to the polymerization of styrene, 3.5 minutes after reaching the maximum temperature (53 ° C.), and after 1 ° C. decrease from the maximum temperature, 520 g of butadiene (1,3-butadiene) was added. For other conditions, Polymer 5 was obtained using the same method as in the production process of Polymer 1 described above. The obtained polymer 5 was colorless and transparent.
In the polymer 5, the content of styrene used for polymerizing the vinyl aromatic monomer unit polymer block (A) was 35% by mass with respect to the entire polymer 5, and the styrene block ratio was 92.1%. The number average molecular weight of component (a) was 61,000, and the number average molecular weight of component (d) was 125,000.
Further, 70% by mass of a block copolymer having a diblock structure of styrene-butadiene, which is a component (a) equivalent product, was contained. The vinyl bond content in the butadiene portion was 12.5%.
Polymer 5 was a mixture of component (d): ((AB) _m X) m = 2 and component (a): (AB).

<Polymer 6: Bifunctional coupling styrene-butadiene block copolymer>
240 g of styrene was charged, and after lapse of 21 minutes after the maximum temperature (53 ° C.) was reached by polymerization of styrene, and after the temperature decreased by 6 ° C. from the maximum temperature, 560 g of butadiene (1,3-butadiene) was added. Other conditions were obtained using the same method as in the polymer 1 production process described above. The obtained polymer 6 was yellow.
In the polymer 6, the content of styrene used for polymerizing the vinyl aromatic monomer unit polymer block (A) is 30% by mass with respect to the entire polymer 6, and the styrene block ratio is 99.5%. The number average molecular weight of component (a) was 62,000, and the number average molecular weight of component (d) was 120,000.
Further, 70% by mass of a block copolymer having a diblock structure of styrene-butadiene, which is a component (a) equivalent product, was contained. The vinyl bond content in the butadiene portion was 12.2%.
Polymer 6 was a mixture of component (d): ((AB) _m X) m = 2 and component (a): (AB).

<Polymer 7: Bifunctional coupling styrene-butadiene block copolymer>
The coupling rate was varied by varying the amount of coupling agent ethyl benzoate. Other conditions were obtained using the same method as in the polymer 1 production process described above. The obtained polymer 7 was colorless and transparent.
In the polymer 7, the content of styrene used for polymerizing the vinyl aromatic monomer unit polymer block (A) was 35% by mass with respect to the whole polymer 7, and the styrene block ratio was 97.4%. The number average molecular weight of component (a) was 63,000, and the number average molecular weight of component (d) was 1280,000.
Further, 40% by mass of a block copolymer having a diblock structure of styrene-butadiene, which is a component (a) equivalent product, was contained. The vinyl bond content in the butadiene portion was 12.5%.
Polymer 7 was a mixture of component (d): ((AB) _m X) m = 2 and component (a): (AB).

<Polymer 8: Bifunctional coupling styrene-butadiene block copolymer>
The coupling rate was varied by varying the amount of coupling agent ethyl benzoate. Other conditions were obtained using the same method as in the polymer 1 production process described above to obtain polymer 8. The obtained polymer 8 was colorless and transparent.
In the polymer 8, the content of styrene used for polymerizing the vinyl aromatic monomer unit polymer block (A) is 35% by mass with respect to the entire polymer 8, and the styrene block ratio is 97.3%. The number average molecular weight of component (a) was 63,000, and the number average molecular weight of component (d) was 1280,000.
Moreover, the block copolymer of the diblock structure of styrene-butadiene which is a component (a) equivalent product contained 85 mass%. The vinyl bond content in the butadiene portion was 12.5%.
Polymer 8 was a mixture of component (d): ((AB) _m X) m = 2 and component (a) :( AB).

<Polymer 9: Bifunctional coupling styrene-butadiene block copolymer>
A stainless steel autoclave with a stirrer and a jacket with an internal volume of 10 L was washed, dried and purged with nitrogen, charged with 5720 g of cyclohexane and 280 g of pre-purified styrene, and warm water was passed through the jacket to set the contents at about 40 ° C. .
Next, n-butyllithium cyclohexane solution (1.79 g in pure content) was added to initiate polymerization of styrene.
5 minutes after reaching the maximum temperature (55 ° C.) due to the polymerization of styrene, 520 g of butadiene (1,3-butadiene) was added after the temperature dropped from the maximum temperature by 2.5 ° C., and the polymerization was continued. 25 seconds after almost complete polymerization and reaching the maximum temperature (91 ° 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 parts by mass of octadecyl-3- (3,5-dibutyl-t-butyl-4-hydroxyphenyl) propionate is added with respect to 100 parts by mass of the block copolymer. Then, in the same manner as in the production process of polymer 1 described above, the solution was subjected to steam stripping, the polymerization solvent was separated, and then dried (the obtained block copolymer is referred to as polymer 9). The obtained polymer 9 was colorless and transparent.
In the polymer 9, the content of styrene used for polymerizing the vinyl aromatic monomer unit polymer block (A) was 35% by mass with respect to the whole polymer 9, and the styrene block ratio was 96.0%. The number average molecular weight of component (a) was 15,000, and the number average molecular weight of component (d) was 30,000.
Further, 70% by mass of a block copolymer having a diblock structure of styrene-butadiene, which is a component (a) equivalent product, was contained. The vinyl bond content in the butadiene portion was 12.4%.
Polymer 9 was a mixture of component (d): ((AB) _m X) m = 2 and component (a): (AB).

<Polymer 10: Bifunctional coupling styrene-butadiene block copolymer>
A stainless steel autoclave with a stirrer and a jacket with an internal volume of 10 L was washed, dried and purged with nitrogen, charged with 5720 g of cyclohexane and 280 g of pre-purified styrene, and warm water was passed through the jacket to set the contents at about 40 ° C. .
Next, an n-butyllithium cyclohexane solution (1.39 g in pure content) was added to initiate styrene polymerization.
7 minutes after reaching the maximum temperature (52 ° C.) due to the polymerization of styrene, and after dropping 2 ° C. from the maximum temperature, 520 g of butadiene (1,3-butadiene) was added and the polymerization was continued. 25 seconds after reaching the maximum temperature (88 ° C.) by polymerization, 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 parts by mass of octadecyl-3- (3,5-dibutyl-t-butyl-4-hydroxyphenyl) propionate is added with respect to 100 parts by mass of the block copolymer. Then, in the same manner as in the production process of polymer 1 described above, the solution was subjected to steam stripping, the polymerization solvent was separated, and then dried (the obtained block copolymer is referred to as polymer 10). The obtained polymer 10 was colorless and transparent.
In the polymer 10, the content of styrene used for polymerizing the vinyl aromatic monomer unit polymer block (A) was 35% by mass with respect to the entire polymer 10, and the styrene block ratio was 96.7%. The number average molecular weight of component (a) was 98,000, and the number average molecular weight of component (d) was 196,000.
Further, 70% by mass of a block copolymer having a diblock structure of styrene-butadiene, which is a component (a) equivalent product, was contained. The vinyl bond content in the butadiene portion was 12.7%.
Polymer 10 was a mixture of component (d): ((AB) _m X) m = 2 and component (a): (AB).

Next, the adhesive composition was produced using the block copolymer for various adhesives mentioned above.
[Example 1]
300 parts by mass of Alcon M100 (made by Arakawa Chemical Co., Ltd.) as a tackifier and 100 parts by mass of Diana Process Oil PW-90 (Idemitsu Kosan Co., Ltd.) as a softening agent with respect to 100 parts by mass of the block copolymer (Polymer 1) Manufactured at a blending ratio of 100 parts by mass, and melt-kneaded with a pressurized double-arm kneader (model: D0.3-3, manufactured by Moriyama Seisakusho Co., Ltd.) at 180 ° C. for 30 minutes. A hot-melt adhesive composition was obtained.
In the adhesive composition, 2-t-butyl-6- (3-t-butyl-2-hydroxy-5 as a stabilizer with respect to 100 parts by mass of the block copolymer (Polymer 1). 1 part by mass of -methylbenzyl) -4-methylphenyl acrylate was blended.
According to the measurement method of the physical properties of the above-mentioned adhesive composition, the melt viscosity (at 180 ° C) was 920 (mPa · s) and the softening point was 89.8 ° C.
Further, the coating property was good, the loop tack was 53.4 N / 15 mm, the adhesive strength was 30.7 N / 10 mm, and the holding force was 10.3 minutes.

[Examples 2 to 4], [Comparative Examples 1 to 10]
In accordance with the composition shown in Table 1 and Table 2 below, an adhesive composition using Alcon M100 as a tackifier and Diana Process Oil PW-90 as a softener in the same manner as in Example 1, respectively. Were fabricated and the characteristics were evaluated.
In addition, when the torque was not stable even after 40 minutes of kneading, the kneading was continued until the torque was stabilized.

It turned out that all block copolymers for adhesives (Polymers 1 to 4) of Examples 1 to 4 have practically good finishing properties.
In addition, each of the compositions for adhesives of Examples 1 to 4 has good adhesive properties of loop tack (adhesiveness), adhesive strength, and holding power, and excellent performance balance. It was found that solubility and coatability were also excellent.

  This application is based on a Japanese patent application (Japanese Patent Application No. 2010-232925) filed with the Japan Patent Office on October 15, 2010, the contents of which are incorporated herein by reference.

  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 can be used for back glue and adhesives, especially for adhesive tapes, adhesive sheets and films, adhesive labels, surface protection sheets and films, and hygiene materials there is a possibility.

Claims (5)

A block copolymer comprising at least two vinyl aromatic monomer unit polymer blocks (A) and a polymer block (B) mainly composed of at least one conjugated diene monomer unit; A block copolymer for adhesives,
The amount of vinyl aromatic monomer polymer block (% by mass) in the vinyl aromatic monomer unit polymer block (A) polymerizes the vinyl aromatic monomer unit polymer block (A). 95.0-99.0% with respect to the total vinyl aromatic monomer unit amount (mass%) used,
And,
The block for adhesives which consists of 20-50 mass% of at least any one component chosen from the group which consists of the following component (a) 50-80 mass% and the following component (b), (c), and (d). Copolymer.
(A): A diblock copolymer having a number average molecular weight of 20,000 to 80,000, represented by the general formula (AB).
(B): a block copolymer having a number average molecular weight of 40,000 to 160,000, wherein _n is an integer of 2 or more and (AB) is represented by _n .
(C): a block copolymer having a number average molecular weight of 40,000 to 160,000, wherein _p is an integer of 1 or more and is represented by (AB) pA.
(D): A branched block copolymer having a number average molecular weight of 40,000 to 160,000, wherein m is any one of 2, 3, and 4 and is represented by general formula (AB) _m X. X represents a residue of a coupling agent or a residue of a polymerization initiator. (I) The block copolymer for adhesives according to claim 1: 100 parts by mass;
(Ii) Tackifier: 100 to 400 parts by mass;
(Iii) softening agent: 50 to 150 parts by mass;
An adhesive composition containing The adhesive composition according to claim 2, which satisfies the following requirements (1) to (3).
(1): Loop tack T (N / 15 mm) / 50 is 0.8 or more (2): 180 ° peeling adhesive strength P (N /) measured according to the measuring method of peeling strength of JIS Z0237 10 mm) / 30 is 0.8 or more (3): Holding force C (minute) / 10 is 0.8 or more It is a manufacturing method of the block copolymer for adhesives according to claim 1,
A step of polymerizing a vinyl aromatic monomer unit to produce the vinyl aromatic monomer unit polymer block (A);
4 minutes or more and 20 minutes or less have elapsed from the time when the conjugated diene monomer unit reaches the maximum temperature in the step of polymerizing the vinyl aromatic monomer unit, and the temperature decreases by 1.5 ° C. or more from the maximum temperature. A step of adding at the time of
The manufacturing method of the block copolymer for adhesives which has this. It is a manufacturing method of the block copolymer for adhesives of Claim 1 containing the said component (c),
After the step of polymerizing the vinyl aromatic monomer unit to produce the vinyl aromatic monomer unit polymer block (A), a deactivator for terminating the polymerization of the block copolymer, The block copolymer for adhesives according to claim 4, wherein the block copolymer is added when 4 minutes or more and 20 minutes or less have elapsed from the time when the maximum temperature in the process is reached and when the temperature falls 1.5 ° C or more from the maximum temperature. Method.