JP2006299024A - Block copolymer composition for asphalt pressure-sensitive adhesive agent and asphalt pressure-sensitive adhesive agent composition - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide an asphalt pressure-sensitive adhesive agent composition that has excellent processability, a high softening point and a high low-temperature adhesion strength. <P>SOLUTION: This asphalt pressure sensitive agent composition mainly comprises (A) a polymer block mainly including a monoalkenyl aromatic compound and a conjugated diene compound, the block copolymers composed of 2 kinds of block copolymers (a) and (b) having mutually different average molecular weights where (i) the peak molecular weight of (a) is 200,000 to 400,000 according to the GPC and the peak molecular weight of (b) is 60,000 to 140,000 according to the same and the ratio of the (b) peak to the (a) peak is 0.2 to 0.6; (ii) the amount of total monoalkenyl aromatic compound is 20 to 40 wt.% in the block copolymer composition; (iii) the composition ratio of (b) is 65 to 90 wt.%; and (iv) the MI of the block copolymer composition is 2 to 30. <P>COPYRIGHT: (C)2007,JPO&amp;INPIT

Description

  The present invention relates to an asphalt adhesive composition used in the construction of asphalt roofing and waterproof sheets.

  Conventionally, in the construction of asphalt roofing and waterproof sheets, a so-called thermal construction method, in which a hot melt asphalt is attached to a base material and laminated, has been the mainstream. However, in recent years, from the viewpoints of energy saving, environmental load reduction, and work environment improvement, the roofing material is attached to the base material using an adhesive, or the roofing material having a self-adhesive layer on the back surface is attached to the base material. Many so-called cold work methods have been implemented. For adhesives and self-adhesive layers, SBS, SIS, SBR, butyl rubber, chloroprene or olefin-based compositions, such as compositions based on various rubber polymers, acrylic and epoxy adhesives, etc. Has been. For example, Patent Document 1 discloses a composition based on butyl rubber.

JP-A-8-326228

However, recently, the required performance for this application has become more sophisticated and complicated.For example, it can be used in a wide temperature range, such as no separation at low temperatures and no flow deviation at high temperatures. In repair construction, high adhesive strength is required even when a roofing material is applied to a non-smooth surface layer.
On the other hand, excellent workability (coating property) is also required, and accordingly, development of an adhesive composition that exhibits a high balance of physical properties is expected.
In view of such market requirements, the present invention expresses a high level of physical property balance that is not found in conventional adhesive compositions, in particular, has excellent processability, exhibits high adhesive strength, and can be used in a wide temperature range. An asphalt adhesive composition is provided.

As a result of intensive studies to solve the above problems, the present inventors have found that an adhesive composition containing a block copolymer composition of a specific monoalkenyl aromatic compound and a conjugated diene compound is used. The inventors have found that the above object can be achieved and have completed the present invention.
That is, the present invention
(A) a block copolymer comprising a polymer block mainly composed of a monoalkenyl aromatic compound and a polymer block mainly composed of a conjugated diene compound (a) and (b) comprising two types of block copolymers. ,
(A) A block copolymer (b) wherein (b) comprises at least one polymer block mainly composed of a monoalkenyl aromatic compound and at least one polymer block mainly composed of a conjugated diene compound (b) (a) The peak molecular weight by GPC measurement of 200,000 to 400,000 in terms of standard polystyrene, the peak molecular weight by GPC measurement in (b) of 60,000 to 140,000, and (b) of the peak molecular weight of (b) Ratio to 0.2-0.6
(C) Total monoalkenyl aromatic compound content (TS) in the block copolymer composition is 20 to 40% by weight,
(D) The composition ratio of the block copolymer (b) is 65 to 90% by weight.
(E) MI of the block copolymer composition is 2 to 30
A block copolymer composition for an asphalt adhesive, and the block copolymer composition (A) and / or the block copolymer composition (A) and other rubbery polymers, 3 to 40 parts by weight of the composition, (B) 0 to 60 parts by weight of the tackifier resin, (C) 0 to 50 parts by weight of the softening agent, and (D) 10 to 90 parts by weight of asphalt, and the total is 100 parts by weight. It is related with the asphalt adhesive composition which is.

The present invention is described in detail below.
The component (A) constituting the present invention comprises a block copolymer (a) comprising a polymer block mainly comprising a monoalkenyl aromatic compound and a polymer block mainly comprising a conjugated diene, and a monoalkenyl aromatic compound. A block copolymer composition comprising at least one polymer block mainly comprising a block copolymer (b) comprising at least one polymer block mainly comprising a conjugated diene compound.
The polymer block mainly composed of a monoalkenyl aromatic compound is composed mainly of a monoalkenyl aromatic compound homopolymer block or a substantially monoalkenyl aromatic compound containing 50% by weight or more of a monoalkenyl aromatic compound. A copolymer block is shown. Further, the polymer block mainly composed of a conjugated diene compound refers to a conjugated diene compound homopolymer block or a copolymer block mainly containing a conjugated diene compound containing 50% by weight or more of the conjugated diene compound as a main component. . When the polymer block mainly composed of a conjugated diene compound is, for example, a monoalkenyl aromatic compound-conjugated diene compound copolymer, the monoalkenyl aromatic compound in the copolymer block may be evenly distributed or non-uniform. It may be distributed (for example, tapered). A plurality of uniformly distributed portions and / or non-uniformly distributed portions may coexist in each block.

In the block copolymer composition (A) of the present invention, the physical properties of the resulting adhesive composition, particularly when a high balance between the softening point and the low-temperature adhesiveness is required, the conjugated diene compound is the main component. If the polymer block to be processed is, for example, a copolymer of a monoalkenyl aromatic compound and a conjugated diene compound, the conjugated diene compound is preferably 95% or more.
Examples of the monoalkenyl aromatic compound used in the block copolymers (a) and (b) include styrene, P-methylstyrene, tertiary butylstyrene, α-methylstyrene, 1,1-diphenylethylene, and the like. Examples thereof include monomers, and among them, styrene is preferable. These monomers may be used alone or in combination of two or more.
On the other hand, examples of the conjugated diene compound include simple substances such as 1,3-butadiene, isoprene, 2,3-dimethyl-1,3-butadiene, 3-butyl-1,3-octadiene, and phenyl-1,3-butadiene. Among them, 1,3-butadiene and isoprene are preferable, and 1.3 butadiene is most preferable. These monomers may be used alone or in combination of two or more.

Further, the total monoalkenyl aromatic compound content (TS) in the block copolymer composition (A) is determined in view of the productivity of the block copolymer composition and the softening point of the resulting adhesive composition. From the viewpoint of the adhesive performance of the obtained adhesive composition, it is 40% by weight or less. Preferably, it is more than 25% by weight and 35% by weight or less.
The content of the block copolymer (b) constituting the block copolymer composition (A) of the present invention is the melt viscosity and adhesive performance of the resulting adhesive composition, particularly adhesive performance at low temperatures, etc. In view of the above, it is 65% by weight or more, and from the viewpoint of the softening point of the obtained adhesive composition, it is 90% by weight or less. As content of a block copolymer (b), 70 to 90 weight% is preferable and 75 to 90 weight% is more preferable.

The peak molecular weight of the block copolymer (a) is 200,000 or more in terms of standard polystyrene from the viewpoint of the softening point of the resulting adhesive composition, and the melt viscosity and workability of the resulting adhesive composition From the viewpoint, it is 400,000 or less in terms of standard polystyrene, and a more preferable range is 240,000-350,000.
The peak molecular weight of the block copolymer (b) is 60,000 or more in terms of standard polystyrene from the viewpoint of the softening point of the resulting adhesive composition, the adhesive strength of the resulting adhesive composition, the melt viscosity, From the viewpoint of workability, it is 140,000 or less in terms of standard polystyrene. A preferred range is 75,000 to 120,000.
Further, the ratio of the peak molecular weight of the block copolymer (b) to the peak molecular weight of the block copolymer (a) is the balance of the softening point and melt viscosity, workability and adhesive strength of the resulting adhesive composition. From a viewpoint, it is 0.2-0.6, Preferably it is 0.2-0.45.

The block copolymer composition (A) of the present invention has an MI of 2 to 30, preferably 6 to 20, from the viewpoints of melt viscosity and processability.
In addition, the vinyl bond amount of the conjugated diene portion of the block copolymer composition of the present invention is preferably less than 20% particularly when heat resistance is required. A more preferable range is less than 18%.
Further, when the asphalt adhesive composition of the present invention is required to have a particularly high balance of physical properties, the total content of the polymer block mainly composed of a monoalkenyl aromatic compound in the block copolymer composition (A). (BS) is preferably 90% by weight or more of the total monoalkenyl aromatic compound content (TS).

  The block copolymer composition (A) comprising the block copolymer (a) and (b) constituting the present invention is polymerized with styrene using, for example, an organolithium compound as a polymerization initiator in an inert hydrocarbon solvent. Next, butadiene is polymerized, and the two block copolymers (a) and (b) of the styrene butadiene block copolymer obtained by the method of repeating these operations are optionally polymerized separately and mixed. It is obtained by letting At that time, the molecular weight is adjusted by controlling the amount of the organolithium compound. The composition (A) is mixed after completion of the polymerization reaction, and water, alcohol, acid, etc. are added to deactivate the active species, or after completion of the polymerization reaction (a), (b) the solution is separately lost. After mixing after activation, the mixed solution can be obtained, for example, by separating the polymerization solvent by, for example, steam stripping and then drying. Further, (a) and (b) can be obtained by individually blending the polymer obtained by separating and drying the polymerization solvent with a roll or the like.

The block copolymer composition (A) comprising the block copolymer (a) and (b) constituting the present invention can be obtained by a technique different from the above. That is, after polymerizing the component (b) in the same manner as described above, a copolymer product obtained by adding a predetermined amount of an appropriate coupling agent to the organolithium compound in the polymerization system (a And a desired composition is obtained in the same reaction system. When this method is used, the molecular weight and molecular weight distribution of the polymer block part mainly composed of monoalkenyl aromatic compounds are the same in (a) and (b), so that the cohesive force of the block copolymer composition is improved. And very good adhesive performance.
Moreover, the block copolymer which comprises this invention may hydrogenate a part or all of the unsaturated double bond derived from a conjugated diene. The hydrogenation method is not particularly limited, and is performed using a known technique.

Examples of the inert hydrocarbon solvent used in the present invention include aliphatic hydrocarbons such as butane, pentane, hexane, isopentane, heptane, octane and isooctane, cyclopentane, methylcyclopentane, cyclohexane, methylcyclohexane, ethylcyclohexane and the like. Hydrocarbon solvents such as alicyclic hydrocarbons, aromatic hydrocarbons such as benzene, toluene, ethylbenzene and xylene can be used. These may be used alone or in combination of two or more.
Examples of the organic lithium compound used in the present invention include known compounds such as ethyl lithium, propyl lithium, n-butyl lithium, sec-butyl lithium, tert-butyl lithium, phenyl lithium, propenyl lithium, and hexyl lithium. It is done. Of these, n-butyllithium and sec-butyllithium are preferable. The organolithium compound is used not only as one type but also as a mixture of two or more types. The amount used is selected within a range that provides a desired peak molecular weight.

  In the block copolymers (a) and (b), for example, when the polymer block mainly composed of a conjugated diene compound is a random copolymer block of a monoalkenyl aromatic compound and a conjugated diene compound, the monoalkenyl aromatic After polymerizing the compound, a method of simultaneously charging and polymerizing the monoalkenyl aromatic compound and the conjugated diene compound, a method of simultaneously polymerizing a part of the monoalkenyl aromatic compound and the conjugated diene compound, and then adding the conjugated diene compound, etc. Is also used. Furthermore, it is possible to adjust the monoalkenyl aromatic compound chain distribution by adding a polar compound before the start of polymerization and / or during the polymerization reaction. Examples of the polar compound include ethers and tertiary amines, specifically, ethylene glycol dimethyl ether, tetrahydrofuran, α-methoxytetrahydrofuran, N, N, N ′, N′-tetramethylethylenediamine and the like. One or a mixture of two or more is used. Furthermore, it is also possible to use an alkali metal tertiary alkoxide. Examples of the alkali metal tertiary alkoxide include potassium t-butoxide, potassium t-amyl alkoxide, sodium amyl alkoxide, potassium isopentyl oxide and the like.

Further, in order to adjust the vinyl bond amount of the conjugated diene compound in the block copolymers (a) and (b), for example, ethers and tertiary amines such as ethylene glycol dimethyl ether, tetrahydrofuran , Α-methoxytetrahydrofuran, N, N, N ′, N′-tetramethylethylenediamine or the like, or a mixture of two or more thereof is used.
When the block copolymer (a) constituting the present invention is obtained by coupling reaction of the block copolymer (b), examples of the coupling agent include bifunctional epoxy compounds, dimethyldimethoxysilane, Alkoxy silicon compounds such as dimethyldiethoxysilane, trimethoxymethylsilane, triethoxysilane, tetramethoxysilane, tetraethoxysilane, ester compounds such as methyl benzoate and ethyl benzoate, vinyl allenes such as divinylbenzene And halogenated silicon compounds such as dichlorodimethylsilane and phenylmethyldichlorosilane, tin compounds such as dichlorodimethyltin and tetrachlorotin, and silicon compounds such as tetrachlorosilane. Among these, a trifunctional or higher polyfunctional coupling agent is used from the viewpoint of high performance balance such as softening point and melt viscosity, workability, and low-temperature adhesive strength of the obtained adhesive composition. preferable.

Moreover, in the block copolymer which comprises this invention, the said coupling agent compound may be used independently and may be used with 2 or more types of mixtures.
The component (B) constituting the adhesive composition of the present invention can be selected from a wide variety depending on the intended 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 alicyclic hydrocarbon Known tackifier resins such as resins, hydrogenated terpene resins, and hydrogenated rosin resins can be used, and these tackifier resins can be used in combination of two or more. As for the compounding quantity of a component (B), 60 weight part or less is preferable in 100 weight part of adhesive compositions.
Furthermore, in the composition of this invention, the softener of a component (C) can be used if necessary. The kind of the softening agent is not limited, and known paraffinic, naphthenic, and aromatic process oils and mixed oils thereof can be used. When using a component (C), 50 weight part or less is preferable in 100 weight part of adhesive compositions.

  In addition, the component (D) asphalt constituting the adhesive composition of the present invention is a by-product (petroleum asphalt) during petroleum refining. Or it can be obtained as a natural product (natural asphalt), or a mixture of these and petroleum, and its main component is called bitumen. Specifically, straight asphalt, semi-blown asphalt, blown asphalt, tar, pitch, cutback asphalt added with oil, asphalt emulsion, and the like can be used. These may be mixed and used. In the present invention, straight asphalt having a penetration of 30 to 300 is preferable.

  If necessary, a predetermined amount of an antioxidant is added to the block copolymer composition of the present invention. Moreover, in order to further improve the thermal stability of the adhesive composition of the present invention, it is possible to add an antioxidant when blending the adhesive composition. Antioxidants include, for example, 2,4-bis (n-octylthiomethyl) -O-cresol, 2,4-bis (n-dodecylthiomethyl) -O-cresol as block copolymer antioxidants. 2,4-bis (phenylthiomethyl) -3-methyl-6-tert-butylphenol, n-octadecyl-3- (3 ′, 5′di-tert-butyl-4′-hydroxyphenyl) propionate, 2, 2′-methylenebis (4-ethyl-6-tert-butylphenol), tetrakis- [methylene-3- (3 ′, 5′-di-tert-butyl-4′-hydroxyphenyl) propionate] -methane, 1,3 , 5-trimethyl-2,4,6-tris (3,5-di-tert-butyl-4-hydroxybenzyl) benzene, 2,6-di-tert-butyl 4-methylphenol, 2,6-di-tert-butyl-4-ethylphenol, 2-tert-butyl-6- (3-tert-butyl-2-hydroxy-5-methylbenzyl) -4-methyl Phenyl acrylate, 2,4-di-tert-amyl-6- [1- (3,5-di-tert-amyl-2-hydroxyphenyl) ethyl] phenyl acrylate, 2- [1- (2-hydroxy-3) , 5-Di-tert-pentylphenyl) -ethyl] -4,6-di-tert-pentylphenyl acrylate, 3,9-bis [2- [3- (3-tert-butyl-4-hydroxy-5- Hindered fe such as methylphenyl) -propionyloxy] -1,1-dimethylethyl] -2,4,8,10-tetraoxaspiro [5,5] undecane Compounds, pentaerythritol-tetrakis- (β-lauryl-thio-propionate), dilauryl-3,3′-thiodipropionate, dimyristyl-3,3′-thiodipropionate, distearyl-3, Sulfur compounds such as 3′-thiodipropionate, tris (nonylphenyl) phosphite, cyclic neopentanetetraylbis (octadecyl phosphite), tris (2,4-di-tert-butylphenyl) phosphite, etc. And phosphorus-based compounds. These can be used alone or in admixture of two or more. Although these addition amounts are arbitrary according to a use, Preferably they are 5 weight part or less with respect to 100 weight part of adhesive compositions.

Furthermore, a predetermined amount of light stabilizer may be added to the block copolymer composition of the present invention, if necessary. Moreover, it is also possible to add a light stabilizer at the time of blending the adhesive composition of the present invention. As the light stabilizer, 2- (2′-hydroxy-5′-methylphenyl) benzotriazole, 2- (2′-hydroxy-5′-tert-octylphenyl) benzotriazole, 2- (2′-hydroxy-) 3 ′, 5′-di-tert-butylphenyl) benzotriazole, 2- (2′-hydroxy-3 ′, 5′-di-tert-butylphenyl) -5-chlorobenzotriazole, 2- (2′- Benzotriazole compounds such as hydroxy-3′-tert-butyl-5′-methylphenyl) -5-chlorobenzotriazole, bis (2,2,6,6-tetramethyl-4-piperidyl) sebacate, succinic acid Dimethyl-1- (2-hydroxyethyl) -4-hydroxy-2,2,6,6-tetramethylpiperidine polycondensate, poly [(6- (1,1,3, 3-tetramethylbutyl) imino-1,3,5-triazine-2,4-diyl) [2,2,6,6-tetramethyl-4-piperidyl] imino] hexamethylene [[2,2,6 Hindered amine compounds such as 6-tetramethyl-4-piperidyl] imino]] and benzophenone compounds such as 2-hydroxy-4-methoxybenzophenone.
By combining such a benzotriazole compound, a hindered amine compound, a benzophenone compound and the like with the composition of the present invention, the light resistance can be further improved.

In addition to the above antioxidants and light stabilizers, the composition of the present invention includes various additives conventionally used in asphalt compositions as necessary, such as silica, talc, calcium carbonate, mineral powder, glass fiber, and the like. Fillers and reinforcing agents, mineral aggregates, pigments such as bengara and titanium dioxide, waxes such as paraffin wax, microcrystalline wax and low molecular weight polyethylene wax, or foaming agents such as azodicarbonamide, atactic polypropylene , Polyolefin-based 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-isobuty Rubber, polypentenamer rubber, styrene-butadiene block copolymer, styrene-isoprene block copolymer, hydrogenated styrene-butadiene block copolymer, hydrogenated styrene-isoprene block copolymer other than the present invention Synthetic rubber such as coalescence may be added.
The method of mixing the adhesive composition of the present invention is not limited sometimes, and if desired, the above-mentioned various additives may be mixed with known mixers, hot melt kettles, rolls, kneaders, Banbury mixers, extruders, etc. Is adjusted by heating, melt-kneading and uniformly mixing.

In order to describe the present invention in more detail, examples and comparative examples are shown below, but these examples specifically illustrate the present invention and the excellent effects obtained thereby. The scope of the present invention is not limited at all. Various measurements were performed according to the following methods.
A) Analysis of block copolymer;
A-1) Total styrene content (TS) of block copolymer composition
It calculated from the absorption intensity of 262 nm using the ultraviolet spectrophotometer (Hitachi UV200). A-2) Peak molecular weight of block copolymer (a), (b), ratio of peak molecular weight of block copolymer (b) to peak molecular weight of block copolymer (a) (in Table 1, (b ) / (A)), and the composition ratio of the block copolymer (b) in the block copolymer composition GPC (equipment manufactured by Waters, column used by Polymer Laboratories MINIMIX) Tetrahydrofuran was used as the solvent, and the measurement conditions were a temperature of 35 ° C., a flow rate of 0.4 ml / min, a sample concentration of 0.1% by weight, and an injection volume of 40 μl. The composition ratio was determined. In addition, the peak molecular weight is the following standard polystyrene (manufactured by Waters Co., Ltd. 1.54 × 10 ⁶ , 4.1 × 10 ⁵ , 1.10 × 10 ⁵ , 3.5 × 10 ⁴ , 8.5 × 10 ³ , 1.8 × 10 ³ ) A conversion value from a calibration curve.

A-3) Total block styrene content (BS) in the block copolymer composition
Oxidative decomposition method using osmium tetroxide and t-butyl hydroperoxide (described in “Journal of Polymer Science” Vol. 1, page 429 (1946)) Obtained. The content of the styrene polymer block was calculated from the absorption intensity at 262 nm using an ultraviolet spectrophotometer (Hitachi UV 200).
A-4) MI
The MI was measured according to JIS K7210, Method A, under test conditions 8 in Table 1 (corresponding to test temperature 200 ° C., test load 5 kgf ASTM G condition).
B) Measurement of physical properties of the adhesive composition;
B-1) Melt viscosity:
It was measured with a Brookfield viscometer at a predetermined temperature.
B-2) Softening point Measured according to JIS-K 2207.

Example 1
The block copolymer used in the examples of the present invention was produced as follows.
A 40 L stainless steel reactor equipped with a jacket and a stirrer was sufficiently purged with nitrogen, and then 17,600 g of cyclohexane, 4.8 g of tetrahydrofuran and 960 g of styrene were charged, and the contents were set to about 55 ° C. by passing warm water through the jacket. Thereafter, an n-butyllithium cyclohexane solution (pure 3.6 g) was added to initiate polymerization of styrene. Five minutes after the styrene is almost completely polymerized and reaches the maximum temperature, 2240 g of butadiene (1,3-butadiene) is added and the polymerization is continued, and the butadiene is almost completely polymerized to a maximum temperature of about 90 ° C. Four minutes after reaching, 0.18 equivalent of tetramethoxysilane as a coupling agent was added to n-butyllithium to cause a coupling reaction. Immediately after the styrene was charged, the system was continuously stirred with a stirrer during this period.

The obtained block copolymer solution was extracted, 20 g of water was added, and after stirring, 7.5 g of n-octadecyl-3- (3 ′, 5′di-tert-butyl-4′-hydroxyphenyl) propionate was added. Then, 2.5 g of 2,4-bis (n-octylthiomethyl) -O-cresol was added, and the resulting solution was subjected to steam stripping to remove the solvent to obtain a hydrous crumb. Subsequently, it was dehydrated and dried with a hot roll to obtain a block copolymer composition sample.
60 g of the block copolymer composition thus obtained and 400 g of straight asphalt 60-80 (manufactured by Shin Nippon Oil Co., Ltd.) were blended, melted and kneaded in a 1 liter container with a stirrer at 180 ° C. for 3 hours. An adhesive composition was obtained.

(Examples 2 and 3)
It was obtained by polymerization in the same manner as in Example 1 except that the amount of styrene, butadiene (1,3-butadiene) charged, the amount of n-butyllithium cyclohexane solution added, and the amount of coupling agent tetramethoxysilane were changed. A block copolymer solution was obtained. During this time, the system was continuously stirred with a stirrer. The obtained block copolymer solution was solvent-removed and dried in the same manner as in Example 1 to obtain a block copolymer composition, which was blended in the same manner as in Example 1, and an adhesive composition. Got.
Example 4
A 40 L stainless steel reactor equipped with a jacket and a stirrer was sufficiently purged with nitrogen, and then 17,600 g of cyclohexane, 4.8 g of tetrahydrofuran and 900 g of styrene were charged, and the contents were set to about 55 ° C. by passing warm water through the jacket. Thereafter, an n-butyllithium cyclohexane solution (pure 2.8 g) was added to initiate polymerization of styrene. Styrene is almost completely polymerized, and 5 minutes after reaching the maximum temperature, 2300 g of butadiene (1,3-butadiene) is added to continue the polymerization. After butadiene is almost completely polymerized, the maximum temperature is reached. Four minutes later, 0.17 equivalent of dichlorodimethylsilane as a coupling agent was added to n-butyllithium to cause a coupling reaction. Immediately after the styrene was charged, the system was continuously stirred with a stirrer during this period. The obtained block copolymer solution was subjected to solvent removal and drying in the same manner as in Example 1 to obtain a block copolymer composition, which was blended in the same manner as in Example 1, and the adhesive composition was prepared. Obtained.

(Comparative Examples 1-3)
The block copolymer polymer solution obtained by polymerizing with the same formulation as in Example 1 except that the amount of styrene, butadiene (1,3-butadiene) charged, and the amount of n-butyllithium cyclohexane solution added was changed, Four minutes after almost complete polymerization and the maximum temperature was reached, 0.45 equivalent of tetramethoxysilane as a coupling agent was added to n-butyllithium to cause a coupling reaction. Immediately after the styrene was charged, the system was continuously stirred with a stirrer during this period. The obtained block copolymer solution was solvent-removed and dried in the same manner as in Example 1 to obtain a block copolymer composition, which was blended in the same manner as in Example 1, and an adhesive composition. Got.
Table 1 shows the structures of the obtained block copolymer compositions and the physical properties of the adhesive composition containing them. By using the block copolymer composition having a specific structure defined in the present invention, the melt viscosity is low and the low-temperature processability is excellent, and the adhesive performance is particularly excellent in the balance between the softening point and the low-temperature adhesive force. It turns out that an adhesive composition is obtained.

The present invention relates to a block copolymer composition of a monoalkenyl aromatic compound having a specific structure and a conjugated diene compound, and an asphalt adhesive composition containing the block copolymer composition, Meets advanced market requirements in recent years, expresses a high balance of physical properties not found in conventional adhesive compositions, especially with excellent workability, high softening point and high low-temperature adhesive strength, used in a wide temperature range A possible asphalt adhesive composition is provided.

Claims (5)

(A) a block copolymer comprising a polymer block mainly composed of a monoalkenyl aromatic compound and a polymer block mainly composed of a conjugated diene compound (a), comprising two types of block copolymers (b),
(A) A block copolymer (b) wherein (b) comprises at least one polymer block mainly composed of a monoalkenyl aromatic compound and at least one polymer block mainly composed of a conjugated diene compound (b) (a) The peak molecular weight by GPC measurement of 200,000 to 400,000 in terms of standard polystyrene, the peak molecular weight by GPC measurement in (b) of 60,000 to 140,000, and (b) of the peak molecular weight of (b) Ratio to 0.2-0.6
(C) Total monoalkenyl aromatic compound content (TS) in the block copolymer composition is 20 to 40% by weight,
(D) The composition ratio of the block copolymer (b) is 65 to 90% by weight.
(E) MI of the block copolymer composition is 2 to 30
A block copolymer composition for an asphalt adhesive. The block copolymer composition according to claim 1, wherein the composition ratio of the block copolymer (b) is 75 to 90% by weight. The block copolymer composition according to claim 1, wherein the ratio of the peak molecular weight of the block copolymer (b) to (a) is from 0.2 to 0.45. 2. The block copolymer composition according to claim 1, wherein the total content (BS) of the polymer block mainly comprising a monoalkenyl aromatic compound in the block copolymer composition is 90% by weight or more of TS. 3 to 40 parts by weight of the composition of the block copolymer composition (A) or the block copolymer composition (A) and another rubber polymer, (B) 0 to 60 parts by weight of the tackifier resin, C) An asphalt adhesive composition having 0 to 50 parts by weight of a softening agent, (D) 10 to 90 parts by weight of asphalt, and a total of 100 parts by weight.