JPH0641439A - Asphalt composition for pavement - Google Patents

Abstract

PURPOSE:To obtain the asphalt composition having excellent mechanical strengths, low-temperature properties, processability, etc., and a high softening point by mixing a specified block copolymer mixture with asphalt in a specified ratio. CONSTITUTION:The composition comprises 3-15 pts.wt. block copolymer mixture comprising 85-40wt.% block copolymer (A) comprising at least two polymer blocks based on a monoalkenyl aromatic compound (e.g. styrene) and at least one polymer block based on a conjugated diene compound (e.g. butadiene) and 15-60wt.% block copolymer (B) comprising at least one polymer block based on a monoalkenyl aromatic compound and at least one polymer block based on a conjugated diene compound and having a peak molecular weight equivalent of 1/3-2/3 of that of component A as measured by GPC and having a total combined alkenyl aromatic compound content in components A and B of 20-40%, a vinyl bond content in the conjugated diene compound of 50% or below, a melt viscosity (under conditions G) of 0.5-10 and a softening temperature of 80-130 deg.C.

Description

Detailed Description of the Invention

[0001]

FIELD OF THE INVENTION The present invention relates to a novel styrene-butadiene block copolymer composition. In particular, the present invention uses a block copolymer composition having a specific structure as a modifier, has a high softening point, and has a high mechanical strength,
Provided is an asphalt composition having an excellent balance of physical properties such as cold resistance such as elongation at low temperature and processability, for example, an asphalt composition suitable for drainage pavement.

[0002]

2. Description of the Related Art Conventionally, asphalt compositions have been widely used for applications such as road paving, waterproof sheets, sound insulation sheets, and roofing. At that time, many attempts have been made to improve the properties of asphalt by adding various polymers. As specific examples of the polymer, ethylene-vinyl acetate copolymer, ethylene-ethyl acrylate copolymer, rubber latex, block copolymer composed of conjugated diene and vinyl aromatic hydrocarbon, and the like are used.

However, an asphalt composition obtained by adding an ethylene-vinyl acetate copolymer or an ethylene-ethyl acrylate copolymer to asphalt is inferior in low-temperature characteristics, and is not preferable because cracks and the like occur in winter. Also,
Since the elongation property is also inferior and therefore the cohesive force (tenacity) is also inferior, particularly in the case of road paving, the grasping property of the aggregate is inferior.

Further, in the case of rubber latex, although the handling workability when mixing it with asphalt is good, it is economically or process-wise that extra heating is required in order to evaporate the water in the latex. There's a problem. On the other hand, as a solution to the difficulty of latex rubber, an asphalt composition to which a block copolymer composed of an alkenyl aromatic compound and a conjugated diene compound is added has excellent low-temperature properties and has a low elastic modulus, resulting in low processability. There were advantages such as superiority (Japanese Patent Publication No. 47-17319, Japanese Patent Publication No. 5)
9-36949).

However, in recent years, due to the increase in the number of vehicles passing through the road or the speed increase, while maintaining more excellent strength and abrasion resistance, drainage improvement and noise reduction on such highways are achieved. For this purpose, there is an increasing demand for asphalt mixtures with high open particle size (asphalt for drainage pavement). Therefore, higher softening point and toughness, mechanical strength such as tenacity is required, for example, it has been attempted to improve by increasing the molecular weight of the block copolymer, on the other hand, the melt viscosity is high Becomes
There was a problem that the workability of road pavement was significantly sacrificed. As described above, the conventional asphalt composition to which each polymer is added is one that can satisfy the high softening point, the penetration, the elongation and the cold resistance, and the high balance between the processability and the properties required at the same time. Did not exist.

[0006]

DISCLOSURE OF THE INVENTION The present invention solves the problems of the conventional asphalt composition, and has a high softening point, mechanical strength, physical properties such as cold resistance, and high workability. An object is to provide an asphalt composition having excellent balance.

[0007]

The inventors of the present invention have conducted extensive studies to develop an asphalt composition having the above-mentioned preferable physical properties, and as a result, have found that an alkenyl aromatic compound having a specific structure and a conjugated diene compound. It was found that the object can be achieved by the asphalt composition containing the block copolymer composition of the above in the specified range, and the present invention has been completed.

That is, the present invention is a block copolymer (A) comprising at least two polymer blocks mainly composed of a monoalkenyl aromatic compound and at least one polymer block mainly composed of a conjugated diene compound. , At least one monoalkenyl aromatic compound whose peak molecular weight measured by gel permeation chromatography (GPC) corresponds to 1/3 to 2/3 of the block copolymer (A) in terms of standard polystyrene. And at least 1
Consisting of 3 to 15 parts of a block copolymer mixture consisting of the block copolymer (B) with a conjugated diene compound and 85 to 97 parts of asphalt,

In the block copolymers (A) and (B),
Content of all-bonded monoalkenyl aromatic compound is 20 to 4
0% by weight, the vinyl bond content in the conjugated diene compound is 5
0% by weight or less, the content of (A) in the block copolymer mixture is 85 to 40% by weight, the content of (B) is 15 to 60% by weight, and the MI of the block copolymer mixture is Asphalt for road paving, characterized in that (G) is 0.5 to 10 and the softening temperature of the block copolymer mixture measured by static thermomechanical analysis (TMA) is 80 to 130 ° C. It relates to a composition.

The present invention will be described in detail below. The component (A) constituting the present invention comprises a copolymer block of at least two polymer blocks mainly containing a monoalkenyl aromatic compound and at least one polymer block mainly containing a conjugated diene compound. It is a block copolymer. The polymer block mainly composed of a monoalkenyl aromatic compound means a monoalkenyl aromatic compound of 50 to 10
It is a copolymer block with a monoalkenyl aromatic compound alone or a conjugated diene compound contained in an amount of 0% by weight. Also,
The polymer block containing a conjugated diene compound as a main component is a conjugated diene compound alone or a copolymer block with a monoalkenyl aromatic compound containing 50 to 100% by weight of the conjugated diene compound.

The monoalkenyl aromatic hydrocarbon in the copolymer block may be distributed uniformly or in a taper shape. Further, the component (B) constituting the present invention is a copolymer of a polymer block mainly containing at least one monoalkenyl aromatic compound and a polymer block mainly containing at least one conjugated diene compound. It is a block copolymer composed of blocks.

A polymer block containing a monoalkenyl aromatic compound as a main component means a monoalkenyl aromatic compound
It is a copolymer block containing a monoalkenyl aromatic compound alone or a conjugated diene compound contained in an amount of 0 to 100% by weight. Further, the polymer block containing a conjugated diene compound as a main component is a copolymer block containing a conjugated diene compound in an amount of 50 to 100 wt% and a conjugated diene alone or a monoalkenyl aromatic compound. The monoalkenyl aromatic hydrocarbon in the copolymer block may be distributed uniformly or in a taper shape.

The content of the monoalkenyl aromatic hydrocarbon in the block copolymer components (A) and (B) is 20.
-40%. When the content of the monoalkenyl aromatic hydrocarbon is less than 20%, the cohesive force of the monoalkenyl aromatic hydrocarbon polymer block is insufficient and the mechanical strength such as toughness and tenacity is poor. On the other hand, when it exceeds 40%, the softening temperature in the static thermomechanical analysis of the block copolymer is too high, and when the asphalt compound is produced, the dissolution and dispersion time in the asphalt becomes long, and the processability is increased. Is difficult and not preferable. Further, although the melt viscosity of the asphalt compound is low, it is not preferable because the low temperature characteristics are poor.
Preferably, the monoalkenyl aromatic hydrocarbon is 25 to 3
This is the case in the range of 5% by weight.

Examples of the monoalkenyl aromatic compound of the block copolymer components (A) and (B) constituting the present invention include, for example, styrene, P-methylstyrene, tert-butylstyrene, α-methylstyrene, 1, Examples thereof include monomers such as 1-diphenylethylene, and among them, styrene is preferable. These monomers may be used alone or in combination of two or more.

On the other hand, as the conjugated diene, for example, 1,3
-Butadiene, isoprene, 2,3-dimethyl-1,3
Examples include monomers such as butadiene, piperylene, 3-butyl-1,3-octadiene, and phenyl-1,3-butadiene, and among them, 1,3-butadiene and isoprene are preferable. These monomers may be used alone or in combination of two or more.

The peak molecular weight of the component (B) of the present invention measured by gel permeation chromatography (GPC) is 1/3 to 2/3 of the peak molecular weight of the component (A) similarly measured. Is the range. If it is out of this range, that is, if it is less than 1/3, the melt viscosity becomes low and the workability is excellent, but the cohesive force and the softening point are inferior, and the elongation is also inferior. If it exceeds 2/3,
Although the softening point is high, the melt viscosity of the asphalt composition is high, which is not preferable in terms of processability. Furthermore, (A) in the block copolymer components (A) and (B)
It is necessary that the content of the component is 85 to 40% by weight and the content of the component (B) is 15 to 60% by weight. Outside of these ranges, a high balance of physical properties such as melt viscosity, softening point and elongation will not be exhibited.

The component (A) constituting the present invention is obtained by polymerizing styrene using an organic lithium compound as a polymerization initiator in an inert hydrocarbon solvent, then polymerizing butadiene and then polymerizing styrene again. In addition,
By a sequential polymerization method in which styrene and butadiene are polymerized alternately, the amount of the organolithium compound is controlled so that the peak molecular weight in GPC is in the range of 5 × 10 ⁴ to 50 × 10 ⁴ in terms of standard polystyrene. It

The component (B) constituting the present invention is obtained by polymerizing styrene using an organic lithium compound as a polymerization initiator in an inert hydrocarbon solvent, then polymerizing butadiene, and optionally further adding styrene. The peak molecular weight in GPC is ⅓ of the peak molecular weight of the component (A) by the sequential polymerization method in which butadiene and butadiene are alternately polymerized.
It is prepared by controlling the amount of the organolithium compound so as to be in a range of 2/3 times. For the components (A) and (B), after completion of the reaction, water, alcohol, acid, etc. are added to deactivate the active species, and a solution of each component is blended with a predetermined composition, followed by, for example, steam stripping. And so on.

Component (A) and component (B) constituting the present invention
The block copolymer mixture composed of the components can be obtained by a method other than the above. That is, a copolymer product obtained by adding a predetermined amount of an appropriate coupling agent to the organolithium compound in the polymerization system after polymerizing the component (B) in the same manner as described above ( As the component A), a desired mixture is obtained in the same reaction system. When this method is used, the peak molecular weight of the component (A) is limited to an integral multiple of the peak molecular weight of the component (B), but it is industrially advantageous as compared with the above method.

The coupling agent may be bifunctional or trifunctional.
It is possible to use functional ones, but preferably bifunctional coupling agents are used. As such, for example, silicon compounds such as dichlorodimethylsilane, tin compounds such as dichlorodimethyltin,
There are ester compounds such as methyl benzoate, vinyl allenes such as divinylbenzene, etc., and difunctional epoxy compounds, etc., but from the viewpoint of thermal stability and by-products of the resulting block copolymer composition. Most preferred are bifunctional epoxy compounds.

Further, (A) and (B) which constitute the present invention.
The vinyl bond content in the conjugated diene compound polymer block of the component is 50% by weight or less. When the vinyl bond content exceeds 50% by weight, the melting temperature of the block copolymer becomes high and the solubility at the time of blending asphalt becomes difficult, which is not preferable. In addition, the low temperature properties of the asphalt composition will also be poor. More preferably, the vinyl bond content is in the range of 10 to 40% by weight.

The vinyl bond content in the polymer block of the conjugated diene compound is such that, when a polymer is obtained by using an organolithium compound as an initiator, an inert carbon such as n-hexane, cyclohexane, benzene, toluene or octane is used. A small amount of polar compounds such as ethers and tertiary amines in a hydrogen fluoride solvent, such as ethylene glycol dimethyl ether, tetrahydrofuran, α-methoxytetrahydrofuran, N, N, N ′, N′-tetramethylethylenediamine, etc., preferably tetrahydrofuran. Or N,
It can be changed by coexisting a predetermined amount of N, N ', N'-tetramethylethylenediamine.

The melt viscosity (MI) of the mixture obtained by mixing the block copolymer components (A) and (B) constituting the present invention in the above range is G condition (200 ° C., 5 kgf).
Is 0.5-10. If the MI is less than 0.5, the melt viscosity of the asphalt compound is too high, which is not preferable in terms of processability. When MI exceeds 10, the workability is excellent, but the softening point is low,
The high degree of asphalt modification effect of the components (A) and (B) is not exhibited, which is not preferable. More preferably, MI is in the range of 0.8 to 5.0.

Further, static thermomechanical analysis (TMA) of the block copolymer mixture prepared by mixing the components (A) and (B).
The softening temperature measured by is required to be 80 to 130 ° C. When the softening temperature is less than 80 ° C., the cohesive force is poor, the high softening point of the asphalt composition is not exhibited, and the toughness / tenacity is poor. On the other hand, the softening temperature is 1
If it exceeds 30 ° C., the melt viscosity of the asphalt composition becomes too high and the dispersion compatibility with asphalt becomes poor, so that the desired physical properties cannot be obtained. More preferably, it is 95 to 115 ° C.

The present invention effectively exhibits its effect when the block copolymer mixture comprising the components (A) and (B) contains 3 to 15 parts by weight and 85 to 97 parts by weight of asphalt. It If the blending amount of the copolymer in the asphalt composition is less than 3 parts by weight, a satisfactory asphalt modifying effect cannot be obtained. Further, if it is blended in excess of 15 parts by weight, the melt viscosity of the asphalt composition will be high and the processability will be impaired, and it will be economically disadvantageous. More preferably, the copolymer component is 5 to 1
This is the case where 0 parts by weight and 90 to 95 parts by weight of asphalt are mixed.

The asphalt used in the present invention is not particularly limited, and the conventional asphalt,
Examples include straight asphalt, (semi) blown asphalt, and mixtures thereof. Preferable examples include straight asphalt having a penetration of 40 to 120, blown asphalt having a penetration of 10 to 30, and a mixture thereof. Stabilizers such as antioxidants and light stabilizers may be added to the asphalt composition of the present invention, if necessary.

Examples of the stabilizer 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-t-butylphenol), 2,2'
-Methylenebis (4-ethyl-6-t-butylphenol), 2,4-bis [(octylthio) methyl] -o-
Cresol, 2-t-butyl-6- (3-t-butyl-
2-hydroxy-5-methylbenzyl) -4-methylphenyl acrylate, 2,4-di-t-amyl-6-
Hindered phenolic antioxidants such as [1- (3,5-di-t-amyl-2-hydroxyphenyl) ethyl] phenyl acrylate; dilauryl thiodipropionate, lauryl stearyl thiodipropionate, pentaerythritol- Sulfur-based antioxidants such as tetrakis (β-laurylthiopropionate); tris (nonylphenyl) phosphite, tris (2,4-di-t-)
Examples thereof include phosphorus-based antioxidants such as butylphenyl) phosphite.

As the light stabilizer, for example, 2-
(2′-hydroxy-5′-methylphenyl) benzotriazole, 2- (2′-hydroxy-3 ′, 5′-t
-Butylphenyl) benzotriazole, 2- (2'-
Hydroxy-3 ', 5'-di-t-butylphenyl)-
Examples thereof include benzotriazole-based UV absorbers such as 5-chlorobenzotriazole, benzophenone-based UV absorbers such as 2-hydroxy-4-methoxybenzophenone, and hindered amine-based light stabilizers.

In addition to the above stabilizers, the asphalt composition of the present invention may optionally be filled with various additives conventionally used in asphalt compositions, such as silica, talc, calcium carbonate, mineral powder, and glass fiber. Agents and reinforcing agents, mineral aggregates, pigments or softeners such as paraffin-based, naphthene-based and aroma-based process oils, tackifying resins such as coumarone indene resin and terpene resin, and foaming agents such as azodicarbonamide. Polyolefin type or low molecular weight vinyl aromatic type thermoplastic resin such as atactic polypropylene, ethylene-ethyl acrylate copolymer; natural rubber; polyisoprene rubber, polybutadiene rubber, styrene-butadiene rubber, ethylene-propylene rubber, chloroprene rubber , Acrylic rubber,
Synthetic rubbers such as isoprene-isobutylene rubber, polypentenamer rubber, and styrene-butadiene block copolymers and styrene-isoprene block copolymers other than the present invention may be added. In particular, when used for road paving, the asphalt composition is usually
It is used as a mixture with mineral stones, sand, and aggregates such as slag.

The method of mixing the asphalt composition of the present invention is not particularly limited, and if desired, the above-mentioned various additives may be heated and melt-kneaded by using, for example, a heat melting pot, a roll, a kneader, a Banbury mixer or an extruder. It can be prepared by

The present invention will be described below with reference to examples, but these examples do not limit the present invention. In addition, various measurements followed the following methods. Measurement of physical properties of linear block copolymer composition ; 1) Total styrene content : UV spectrophotometer (Hitachi UV 2
00) was used to calculate the absorption intensity at 262 nm. 2) Block styrene content : oxidative decomposition method using osmium tetroxide and t-butyl hydroperoxide ["Journal of Polymer Science" Vol. 1, 429
Page (1946)]. The weight of the styrene polymer block was measured using an ultraviolet spectrophotometer (Hitachi UV200) from the absorption intensity at 262 nm. 3) Microstructure of butadiene block part : Measured using an infrared spectrophotometer (Model 1710 manufactured by Parking Elmer) and measured by the Hampton method. 4) Static thermomechanical analysis : A thermomechanical analyzer (TMA-40 manufactured by Shimadzu Corporation) was used, and a sheet obtained by compression-molding a block copolymer to a thickness of 2 mm had a pin diameter of 0.5 mm.
Using a quartz rod with a cylindrical tip as a detection rod, the temperature change is measured by the penetration method, and the temperature at which the penetration changes abruptly is determined by extrapolation. (Load 10 g, heating rate 5 ° C./min). 5) Peak molecular weight and composition ratio : GPC [The apparatus is manufactured by Waters, and the column is ZORBAX manufactured by DuPont.
It is a combination of two PSM 1000-S and three PSM 60-S in total. Tetrahydrofuran was used as a solvent, and the measurement conditions were a temperature of 35 ° C., a flow rate of 0.7 ml / min, a sample concentration of 0.1% by weight, and an injection amount of 50 μl], and the peak molecular weight and composition ratio were determined. The peak molecular weight is a conversion value from the following standard polystyrene (Waters) calibration curve. 1.75 × 10 ⁶ , 4.1 × 10 ⁵ , 1.12 × 1
0 ⁵ , 3.5 × 10 ⁴ , 8.5 × 10 ³

Measurement of physical properties of asphalt composition : 1) Melt viscosity : Measured at 180 ° C. with a Brookfield viscometer. 2) Toughness and tenacity : Measured according to the test method for paving work (edited by Japan Road Construction Industry Association). 3) Elongation, penetration, softening point : Measured according to JIS-K2207. 4) Cold resistance : Samples (thickness 2) compression molded at 180 ° C.
mm, width 20 mm, length 100 mm) is immersed in a dry ice / methanol refrigerant kept at a predetermined temperature for 15 minutes, and quickly bent along a metal rod with a diameter of 15 mm. The evaluation was made in 3 ranks, with x being the one and Δ being the middle.

(Example 1) A 40-liter stainless steel reactor equipped with a jacket and a stirrer was thoroughly replaced with nitrogen, and then 17,480 g of cyclohexane and 3.5 of tetrahydrofuran were used.
g and 960 g of styrene were charged, and warm water was passed through the jacket to set the content at about 65 ° C. After that, an n-butyllithium cyclohexane solution (5.2 g of pure content) was added to start polymerization of styrene. 3 minutes after the styrene was almost completely polymerized, 2,240 g of butadiene (1,3-butadiene) was added to continue the polymerization, and after the butadiene was almost completely polymerized and the maximum temperature reached about 95 ° C, 4
After a minute, a 1: 1 mixture of the following structural formulas (a) and (b) was added as a coupling agent, and coupling was performed.

[0034]

[Chemical 1]

(However, the structure in the case of n = 0 contains 98% by weight or more.) 10 minutes after the addition of the coupling agent, 1.6 g of water was added. Immediately after the styrene was charged, the system was continuously stirred by a stirrer during this period. After this, the solution of the linear block copolymer composition was extracted,
2,6-di-t-butyl-4-methylphenol 6.4
g, tris (nonylphenyl) phosphite (4 g) was added, and the solvent was removed by steam stripping the obtained solution, followed by heating on a hot roll (120 ° C.).
Was dehydrated and dried to obtain a linear block copolymer.

The linear block copolymer thus obtained was measured by GPC, and the low molecular weight component was (B) and the high molecular weight component was (A). The physical property values are shown in Tables 1 and 2. In addition, 6 g of the external linear polymer composition and straight asphalt [store 60/80 manufactured by Nippon Oil Co., Ltd.] 1
00 g was melt-kneaded at 180 ° C. for 90 minutes to prepare an asphalt composition. The characteristics are shown in Tables 1-2.

(Examples 2, 4 and Comparative Examples 1-4, 6,
7) In Examples 2 and 4 and Comparative Examples 1 to 4, 6, and 7, the coupling agent used in Example 1 was used, and the total styrene content was
A composition ratio of the block copolymer (A) component and the (B) component,
MI was used as a variable. The same asphalt was used as in Example 1, and the asphalt composition and composition were the same as in Example 1 in the same amount and method.

(Example 3, Comparative Example 5) In Example 3 and Comparative Example 5, when the same polymerization as in Example 1 was carried out, tetramethylethylenediamine was added to cyclohexane in an appropriate amount to coexist with the butadiene. The vinyl content in the was varied. The same asphalt was used as in Example 1, and the asphalt composition and blending method were the same as in Example 1. Table 1 shows the physical property values of Examples 2 to 4 and Comparative Examples 1 to 7.
Shown in 2.

[0039]

[Table 1]

[0040]

[Table 2]

From this table, the block copolymer mixture is
It can be seen that when the structure is within the specified range, the physical properties of the asphalt composition show a high softening point, high toughness and tenacity while maintaining a low melt viscosity, and also have excellent low temperature properties.

(Examples 5 and 6) (Production Method of Block Copolymer Component (A)) A 40 L stainless steel reactor equipped with a jacket and a stirrer was sufficiently replaced with nitrogen, and then a predetermined amount of cyclohexane, tetrahydrofuran or styrene ( First styrene) was charged, warm water was passed through the jacket, and the content was set to about 70 ° C.

Thereafter, a predetermined amount of n-butyllithium cyclohexane solution was added to initiate the polymerization of the first styrene. 10 minutes after the first styrene was almost completely polymerized, a predetermined amount of butadiene (1,3-butadiene) was added to continue the polymerization, and 15 minutes after butadiene was almost completely polymerized and reached the maximum temperature. After that, again, a predetermined amount of styrene (referred to as secondary styrene) was added to continue the polymerization, and after the secondary styrene was polymerized almost completely, the polymerization was completed by holding it for another 15 minutes, and then water was added. To completely inactivate the active species. Then, 2,6-di-t-butyl-4-methylphenol and tris (nonylphenol) phosphite (cyclohexane solution) were added.

(Production Method of Block Copolymer Component (B)) A 40 L stainless steel reactor equipped with a jacket and a stirrer was sufficiently replaced with nitrogen, and then predetermined amounts of cyclohexane, tetrahydrofuran and styrene (referred to as primary styrene) were added. Preparation, warm water is passed through the jacket, the contents are about 70 ℃
Set to. Then, a predetermined amount of n-butyllithium cyclohexane solution was added to initiate polymerization of the first styrene. 10 minutes after the first styrene was almost completely polymerized, butadiene (1,3-butadiene) was added in a predetermined amount to continue the polymerization, and 15 minutes after the butadiene was almost completely polymerized and reached the maximum temperature. After the temperature was maintained and the polymerization was completed, water was added to completely deactivate the active species.

After this, 2,6-di-t-butyl-4-methylphenol and tris (nonylphenol) phosphite (cyclohexane solution) were added. The polymer solutions of the component (A) and the component (B) obtained by the above method are
The solvent was removed by mixing with a solution so as to have a predetermined composition ratio and steam stripping the obtained solution, followed by dehydration drying with a hot roll (120 ° C.) to obtain a linear block copolymer. Got The block copolymer composition thus obtained was used as an asphalt composition using the same asphalt as in Example 1 and with the same blending amount. The above-mentioned physical property values are shown in Table 3.

(Example 7, Comparative Example 8) When a block copolymer mixture was obtained by the same polymerization as in Example 1, dichlorodimethylsilane was used in Example 7 and silicon tetrachloride was used in Comparative Example 8 as a cup. A predetermined amount was used as a ring agent. As the asphalt composition, the same asphalt as in Example 1 was used, and the same blending amount was used. The physical property values are shown in Table 3.

(Comparative Example 9) In Comparative Example 9, Examples 5 and 6 were used.
A single-component linear block copolymer prepared by a method similar to the method for producing the block copolymer component (A) shown in 1 above was used to obtain an asphalt composition with the same asphalt and compounding amount as in Example 1. . The above-mentioned physical property values are shown in Table 3.

[0048]

[Table 3]

From Table 3, when the block copolymer single component (A) is a mixture with respect to (A), the block copolymer single component (B) in the specified molecular weight range, It can be seen that it has an excellent asphalt modification effect. Moreover, from the physical property values shown in Tables 1 and 2 and 3, the copolymer mixture obtained by blending the block copolymer components (A) and (B) is a copolymer in a specified range. It can be seen that excellent effects are exhibited regardless of the method for producing the composition.

(Examples 8 and 9 and Comparative Example 10) In Examples 8, 9 and Comparative Example 10, the composition ratio of the block copolymer mixture prepared in Example 1 and the asphalt used in Example 1 was determined. Was taken as the variable. Their physical properties are shown in Table 4.

[0051]

[Table 4]

From Table 4, it can be seen that the block copolymer mixture exhibits an excellent modifying effect when the compounding amount is specified.

[0053]

INDUSTRIAL APPLICABILITY The asphalt composition of the present invention is excellent in physical properties such as mechanical strength, softening point, elongation and cold resistance, and has a high degree of balance in workability. As a matter of course, it can be used for applications such as a waterproof sheet, a sound insulation sheet, and a water blocking material, and its industrial significance is great.

[Brief description of drawings]

1 is a graph showing the softening temperature of the block copolymer mixture obtained in Example 1, as measured by static thermomechanical analysis (TMA).

Claims (1)

[Claims] 1. A block copolymer (A) comprising a polymer block mainly containing at least two monoalkenyl aromatic compounds and a polymer block mainly containing at least one conjugated diene compound, and gel permeation. The block copolymer (A) has a peak molecular weight measured by chromatography (GPC) in terms of standard polystyrene.
3 to 15 parts of a block copolymer mixture consisting of a block copolymer (B) consisting of at least one monoalkenyl aromatic compound and at least one conjugated diene compound corresponding to 1/3 to 2/3 of , Asphalt 85-97
And the total content of alkenyl aromatic compounds in the block copolymer (A) and the block copolymer (B) is 20 to 4
0% by weight, the vinyl bond content in the conjugated diene compound is 5
0% by weight or less, the content of (A) in the block copolymer is 85 to 40% by weight, the content of (B) is 15 to 60% by weight, and MI () of the block copolymer mixture is G) is 0.5-10, and the softening temperature of the block copolymer mixture measured by static thermomechanical analysis (TMA) is 80-130 ° C., asphalt composition for road paving. object.