JP2016035037A - Asphalt composition - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide an asphalt composition that excellently resists mass loss and strength deterioration in oil adhesion.SOLUTION: An asphalt composition comprises a block copolymer (a) of 1-15 mass%, a crystalline material (b) of 0.5-10 mass% and asphalt (c) of 80 mass% or more, where the block copolymer (a) is a polymer comprising a conjugated diene monomer unit and a vinyl aromatic monomer unit, and a tanδ peak temperature of the block copolymer (a) based on dynamic viscoelasticity test is -50°C to 0°C.SELECTED DRAWING: None

Description

  The present invention relates to an asphalt composition.

Asphalt pavement using asphalt mixture is often performed because it is relatively easy to lay on pavements such as motorways, parking lots, cargo yards, and sidewalks, and the time from the start of pavement work to the start of traffic is short. Yes.
However, since asphalt is produced by refining petroleum, it has the property of dissolving in gasoline, light oil, heavy oil, kerosene, engine lubricating oil, etc., which are the same refined petroleum products. Therefore, when these oils leaked to the road surface due to leakage of fuel or lubricating oil from vehicles, etc., the asphalt was dissolved at an early stage, and the asphalt mixture was invaded, leading to pavement destruction such as potholes. Therefore, it becomes necessary to repair the pavement, resulting in an increase in maintenance costs and a great influence on automobile traffic.
In order to improve these, Patent Document 1 proposes a composition comprising epoxidized modified SBS, an epoxy curing agent and asphalt.
Patent Document 2 proposes a composition comprising a polyamide resin and asphalt.

Japanese Laid-Open Patent Publication No. 10-139983 JP 2010-236345

However, even the methods disclosed in Patent Document 1 and Patent Document 2 have not yet obtained satisfactory results, and further improvements are desired.
The problem to be solved by the present invention is to provide an asphalt composition that is excellent in resistance to mass loss and strength reduction during oil adhesion.

  The inventors of the present invention have made various studies to solve the above-mentioned problems. By mixing a specific block copolymer, a specific additive, and asphalt at a specific ratio, the mass loss resistance and strength resistance at the time of oil adhesion are reduced. It discovered that the asphalt composition excellent in a fall could be obtained, and completed this invention.

That is, the present invention is as follows.
[1] An asphalt composition containing 1 to 15% by mass of the block copolymer (a), 0.5 to 10% by mass of the crystalline material (b), and 80% by mass or more of asphalt (c),
The block copolymer (a) is a polymer containing a conjugated diene monomer unit and a vinyl aromatic monomer unit,
The tan δ peak temperature obtained by the dynamic viscoelasticity test of the block copolymer (a) is in the range of −50 ° C. to 0 ° C.,
Asphalt composition.
[2] The block copolymer (a) is a polymer block (A) mainly composed of a vinyl aromatic monomer unit, and a copolymer containing a conjugated diene monomer unit and a vinyl aromatic monomer unit. Having a block (B),
Asphalt composition as described in [1] whose content of the said polymer block (A) in a block copolymer (a) is 10 to 40 mass%.
[3] The asphalt composition according to [1] or [2], wherein the content of the vinyl aromatic monomer unit in the block copolymer (a) is 20% by mass or more and 60% by mass or less.
[4] The asphalt composition according to any one of [1] to [3], wherein 30 mol% or more of the double bonds in the conjugated diene monomer unit in the block copolymer (a) are hydrogenated.
[5] The asphalt composition according to any one of [1] to [4], wherein the crystalline material (b) has a hetero atom.
[6] The asphalt composition according to any one of [1] to [5], wherein the contents of the block copolymer (a) and the crystalline material (b) satisfy the following relational expression.
(Content of block copolymer (a)) × 0.5 / (Content of crystalline material (b))> 1
[7] The asphalt composition according to any one of [1] to [6], further containing a crosslinking agent.
[8] The block copolymer (a) has at least one functional group selected from a hydroxyl group, an acid anhydride group, an epoxy group, an amino group, an amide group, a silanol group, and an alkoxysilane group. The asphalt composition according to any one of 1] to [7].
[9] An asphalt mixture comprising the asphalt composition according to any one of [1] to [8] and an aggregate.

  The asphalt composition of the present invention is excellent in resistance to mass loss and strength reduction during oil adhesion.

  Hereinafter, a mode for carrying out the present invention (hereinafter referred to as “the present embodiment”) will be described in detail. The present invention is not limited to the following embodiment, and can be implemented with various modifications within the scope of the gist.

<Asphalt composition>
Asphalt composition of this embodiment,
An asphalt composition containing 1 to 15% by mass of a block copolymer (a), 0.5 to 10% by mass of a crystalline material (b) and 80% by mass or more of asphalt (c),
The block copolymer (a) is a polymer containing a conjugated diene monomer unit and a vinyl aromatic monomer unit,

The tan δ peak temperature obtained by the dynamic viscoelasticity test of the block copolymer (a) is in the range of −50 ° C. to 0 ° C.

<Block copolymer (a)>
The block copolymer (a) used in the present embodiment is a polymer containing a conjugated diene monomer unit and a vinyl aromatic monomer unit, and is a polymer block mainly composed of a vinyl aromatic monomer unit. It is preferable to have (A) and a copolymer block (B) containing a conjugated diene monomer unit and a vinyl aromatic monomer unit. In the present embodiment, the polymer block (A) is a block mainly composed of vinyl aromatic monomer units. Here, “mainly” means that the polymer block (A) contains a vinyl aromatic monomer unit in an amount of more than 95% by mass and 100% by mass or less, preferably 96% by mass to 100%. It is contained by mass% or less, more preferably 97 mass% or more and 100 mass% or less.
It is preferable that content of a polymer block (A) is 10 to 40 mass% with respect to a block copolymer (a). When the content of the polymer block (A) in the polymer is within the above range, an asphalt composition having a high softening point and a high mass loss resistance and a high strength reduction during oil adhesion can be obtained. The content of the polymer block (A) in the block copolymer (a) is more preferably 15% by mass or more and 35% by mass or less, more preferably 20% by mass or more and 30% by mass or less, and most preferably. Is 20 mass% or more and 27 mass% or less.

Content of a polymer block (A) can be measured by the method as described in the Example mentioned later.
When the block copolymer (a) is hydrogenated, the content of the polymer block (A) in the block copolymer (a) is determined based on the polymer block ( In this embodiment, the content of the polymer block (A) when the block copolymer (a) is hydrogenated is the same as that before the hydrogenation. You may obtain | require as content of the polymer block (A) with respect to.

In this embodiment, the copolymer block (B) is a copolymer block containing a conjugated diene monomer unit and a vinyl aromatic monomer unit, and the vinyl aromatic unit in the copolymer block (B). The content of the monomer unit means 95% by mass or less. The content of the vinyl aromatic monomer unit in the copolymer block (B) is preferably 5% by mass to 95% by mass, more preferably 6% by mass to 80% by mass, and even more preferably 7%. The mass is from 50% by mass to 50% by mass, and most preferably from 10% by mass to 40% by mass.
The copolymer block (B) is preferably a random block. Here, the “random block” refers to a state in which 95% by mass or more of the copolymer block (B) has 10 or less continuous vinyl aromatic monomer units.

In this embodiment, it is preferable that content of the vinyl aromatic monomer unit in a block copolymer (a) is 20 mass% or more and 60 mass% or less with respect to a block copolymer (a). An asphalt composition having excellent softening point and elongation when the content of vinyl aromatic monomer units in the block copolymer (a) is within the above range, and excellent resistance to mass loss and deterioration in strength when adhering to oil. Things are obtained. More preferably, they are 25 to 55 mass%, More preferably, they are 30 to 55 mass%, Most preferably, they are 30 to 50 mass%.
The content of the vinyl aromatic monomer unit can be measured by the method described in the examples described later.

From the viewpoint of obtaining an asphalt composition having a high heat aging resistance, a high mass loss resistance and a high strength reduction at the time of oil adhesion, the double bond in the conjugated diene monomer unit in the block copolymer (a) It is preferable that 30 mol% or more is hydrogenated. It is more preferably 40% or more and less than 90%, further preferably 50% or more and less than 90%, and most preferably 60% or more and less than 90%. In the present specification, the conjugated diene monomer unit is referred to as a conjugated diene monomer unit even after hydrogenation.
In this embodiment, the rate of hydrogenation (hydrogenation rate) can be determined by the method described in the examples described later.

  In this embodiment, the melt flow rate (MFR, 200 ° C., 5 kgf) of the block copolymer (a) obtains an asphalt composition having a high softening point, a high mass loss resistance at the time of oil adhesion, and a high strength resistance reduction. From this viewpoint, it is preferably 10 g / 10 min or less. 3 g / 10 min or less is more preferable, and 1 g / 10 min or less is more preferable.

In this embodiment, the weight average molecular weight (Mw) of the block copolymer (a) is preferably 50,000 or more and 300,000 or less, more preferably, in terms of the balance between the softening point and the melt viscosity of the asphalt composition. It is 100,000 to 280,000, more preferably 150,000 to 260,000.
The weight average molecular weight and the weight average molecular weight can be determined by the method described in the examples described later.

In this embodiment, the structure of the block copolymer (a) can be any structure. For example, what has a structure represented by a following formula is mentioned.
(A−B) _{n + 1} , A− (B−A) _n , B− (A−B) _{n + 1} , [(A−B) _n ] _m −X, [(B−A) _n −B _{] m -X, [(A-} B) n -A] m -X, [(B-A) n + 1] m -X
(In the above formula, each A independently represents a polymer block (A). Each B independently represents a polymer block (B). Each n independently represents an integer of 1 or more. , Preferably an integer of 1 to 5. Each m is independently an integer of 2 or more, preferably an integer of 2 to 11. Each X is independently a residue of a coupling agent or a large number. Represents the residue of a functional initiator.)
The block copolymer (a) may be any mixture having the structure represented by the above formula.
Among these, the A-B-A structure is preferable from the viewpoint of the balance of asphalt binder performance.

In the present embodiment, the vinyl aromatic monomer units in the polymer block (B) may be uniformly distributed, or may be distributed in a tapered shape, a staircase shape, a convex shape, or a concave shape. . Here, the taper structure means a structure in which the content of vinyl aromatic monomer units gradually increases along the polymer chain in the polymer block (B). The content of the vinyl aromatic monomer unit in the polymer block (B) immediately after the start of polymerization of the polymer block (B) is S1, during the polymerization, for example, when half of the introduced monomer is polymerized. When the content of the vinyl aromatic monomer unit in the polymer of S2 is S2, and the content of the vinyl aromatic monomer unit in the polymer block (B) after the polymerization is S3, S2 / S1> 1 and S3 / S2> 1.
From the viewpoint of obtaining an asphalt composition having a high softening point, the concentration of the vinyl aromatic monomer unit in the polymer block (B) is convex (that is, the end of the polymer block (B)). The concentration of the vinyl aromatic monomer unit is low and the concentration of the vinyl aromatic monomer unit at the center is high).
In the polymer block (B), a plurality of portions where the vinyl aromatic monomer units are uniformly distributed and / or a portion where the vinyl aromatic monomer units are distributed in a tapered shape may exist. In the polymer block (B), a plurality of segments having different vinyl aromatic monomer unit contents may be present.

The tan δ peak temperature obtained by the dynamic viscoelasticity test of the block copolymer (a) is in the range of −50 ° C. to 0 ° C.
By setting the tan δ peak temperature to −50 ° C. or higher, the compatibility of the block copolymer (a) with the asphalt (c) increases. On the other hand, by setting the tan δ peak temperature to 0 ° C. or lower, the compatibility of the block copolymer (a) with the crystalline material (b) is increased, and it can be used at a low temperature.
The tan δ peak temperature is more preferably −45 ° C. or more and −10 ° C. or less, and further preferably −40 ° C. or more and −20 ° C. or less.
The tan δ peak temperature can be measured by the method described in Examples below.

  The block copolymer (a) is a hydroxyl group, an acid anhydride group, an epoxy group, an amino group, an amide group, a silanol group, an alkoxysilane group in terms of mass loss resistance and strength resistance reduction when the asphalt composition is attached to oil. It preferably has at least one functional group selected from: Among these, a functional group containing an N group is more preferable. The block copolymer (a) preferably contains 2 mol or more of N groups in the molecule, and more preferably contains both O groups and N groups.

<Method for producing block copolymer (a)>
The production method of the block copolymer (a) used in the present embodiment is not limited. For example, in a hydrocarbon solvent, a lithium compound is used as a polymerization initiator, and at least a conjugated diene monomer and a vinyl aromatic monomer are used. A polymerization step for polymerizing to obtain a polymer, a hydrogenation step for adding hydrogen to a double bond in a conjugated diene monomer unit of the polymer obtained as necessary, and removing a solvent of a solution containing the polymer. The solvent removal step can be sequentially performed for production.

  A conjugated diene monomer is a diolefin having a pair of conjugated double bonds. The conjugated diene monomer is not particularly limited. For example, 1,3-butadiene, 2-methyl-1,3-butadiene (isoprene), 2,3-dimethyl-1,3-butadiene, 1,3- Examples include pentadiene, 2-methyl-1,3-pentadiene, and 1,3-hexadiene. Of these, 1,3-butadiene and isoprene are preferable. Moreover, 1,3-butadiene is more preferable from the viewpoint of improving the holding power of the adhesive composition. A conjugated diene monomer may be used individually by 1 type, and may use 2 or more types together.

Although it does not specifically limit as a vinyl aromatic monomer, For example, styrene, (alpha) -methylstyrene, p-methylstyrene, divinylbenzene, 1,1-diphenylethylene, N, N-dimethyl-p-aminoethyl styrene, N, N-diethyl-p-aminoethylstyrene and the like can be mentioned. Of these, styrene is preferable from the viewpoint of economy. A vinyl aromatic monomer may be used individually by 1 type, and may use 2 or more types together.
The block copolymer (a) may contain a monomer unit other than the vinyl aromatic monomer unit and the conjugated diene monomer unit. In the polymerization step, the vinyl aromatic monomer and the conjugated diene monomer In addition to the polymer, other monomers copolymerizable with the monomer can be used.

The polymerization method carried out in the polymerization step in the production method of the block copolymer (a) is not particularly limited, and known methods can be applied. Known methods include, for example, Japanese Patent Publication No. 36-19286, Japanese Patent Publication No. 43-17799, Japanese Patent Publication No. 46-32415, Japanese Patent Publication No. 49-36957, Japanese Patent Publication No. 48-2423, and Japanese Patent Publication No. Sho. Examples thereof include methods described in Japanese Patent No. 48-4106, Japanese Patent Publication No. 56-28925, Japanese Patent Application Laid-Open No. 59-166518, Japanese Patent Application Laid-Open No. 60-186777, and the like.
It is preferable to add a functional group to the block copolymer (a) using a compound having a functional group as an initiator, a monomer, a coupling agent, or a stopper.
As the initiator containing a functional group, an initiator containing an N group is preferable, and dioctylaminolithium, di-2-ethylhexylaminolithium, ethylbenzylaminolithium, (3- (dibutylamino) -propyl) lithium, piperidy Nolithium and the like can be mentioned.
Examples of the monomer containing a functional group include compounds containing a hydroxyl group, an acid anhydride group, an epoxy group, an amino group, an amide group, a silanol group, and an alkoxysilane group in the monomers used for the above-described polymerization. Among these, a monomer containing an N group is preferable, and N, N-dimethylvinylbenzylamine, N, N-diethylvinylbenzylamine, N, N-dipropylvinylbenzylamine, N, N-dibutylvinylbenzylamine, N, N-diphenylvinylbenzylamine, 2-dimethylaminoethylstyrene, 2-diethylaminoethylstyrene, 2-bis (trimethylsilyl) aminoethylstyrene, 1- (4-N, N-dimethylaminophenyl) -1-phenylethylene N, N-dimethyl-2- (4-vinylbenzyloxy) ethylamine, 4- (2-pyrrolidinoethyl) styrene, 4- (2-piperidinoethyl) styrene, 4- (2-hexamethyleneiminoethyl) styrene, 4- (2-morpholinoethyl) styrene, 4- (2-thiazinoethyl) ) Styrene, 4- (2-N-methyl-piperazino-ethyl) styrene, 1 - ((4-vinyl) methyl) pyrrolidine, 1- (4-vinyl benzyloxycarbonyl) pyrrolidine, and the like.
Examples of the coupling agent and terminating agent containing a functional group include compounds containing a hydroxyl group, an acid anhydride group, an epoxy group, an amino group, an amide group, a silanol group, and an alkoxysilane group among the above-described coupling agents. Among these, a coupling agent containing an N group or an O group is preferable. Tetraglycidylmetaxylenediamine, tetraglycidyl-1,3-bisaminomethylcyclohexane, tetraglycidyl-p-phenylenediamine, tetraglycidyldiaminodiphenylmethane, diglycidylaniline Γ-caprolactone, γ-glycidoxyethyltrimethoxysilane, γ-glycidoxypropyltrimethoxysilane, γ-glycidoxypropyltriphenoxysilane, γ-glycidoxypropylmethyldimethoxysilane, γ-glycidoxy Examples thereof include propyldiethylethoxysilane, 1,3-dimethyl-2-imidazolidinone, 1,3-diethyl-2-imidazolidinone, N, N′-dimethylpropyleneurea, N-methylpyrrolidone and the like.

(Hydrogenation process)
The hydrogenation step is a step of hydrogenating (hydrogenating) a part of the double bond in the conjugated diene monomer unit of the block copolymer (a) obtained in the polymerization step. The catalyst used in the hydrogenation reaction is not particularly limited. For example, a supported heterogeneous catalyst in which a metal such as Ni, Pt, Pd, or Ru is supported on a support such as carbon, silica, alumina, or diatomaceous earth. A so-called Ziegler-type catalyst using an organic salt such as Ni, Co, Fe, or Cr or an acetylacetone salt and a reducing agent such as organic Al; a so-called organic complex catalyst such as an organometallic compound such as Ru or Rh, or reduction to a titanocene compound Examples of the catalyst include a homogeneous catalyst using organic Li, organic Al, organic Mg, and the like. Among these, a homogeneous catalyst system using organic Li, organic Al, organic Mg or the like as a reducing agent for the titanocene compound is preferable from the viewpoint of economy, colorability of the polymer, or adhesive strength.

The hydrogenation method is not particularly limited. For example, the method described in Japanese Patent Publication No. 42-8704 and Japanese Patent Publication No. 43-6636, preferably Japanese Patent Publication No. 63-4841 and Japanese Patent Publication No. 63-5401. The method described in the gazette is mentioned. Specifically, hydrogenated block copolymer solution can be obtained by hydrogenation in the presence of a hydrogenation catalyst in an inert solvent.
The hydrogenation reaction is not particularly limited, but is preferably performed after the step of deactivating the active terminal of the polymer described above from the viewpoint of high hydrogenation activity.

  In the hydrogenation step, the conjugated bond of the vinyl aromatic monomer unit may be hydrogenated. The hydrogenation rate of the conjugated bond in all vinyl aromatic monomer units is preferably 30 mol% or less, more preferably 10 mol% or less, and further preferably 3 mol% or less. Moreover, the minimum of the hydrogenation rate of the conjugated bond in all vinyl aromatic monomers is not specifically limited, However, It is preferable that it is 0 mol% or more, and 1 mol% or more is more preferable. When the hydrogenation rate of the conjugated bond in the total vinyl aromatic monomer is within the above range, the holding power and the adhesiveness tend to be further improved.

  From the viewpoint of heat aging resistance and gelation suppression of the block copolymer (a), it is preferable to add an antioxidant to the asphalt composition of the present embodiment. The antioxidant is not particularly limited, and examples thereof include phenolic antioxidants such as radical scavengers, phosphorus antioxidants such as peroxide decomposers, and sulfur antioxidants. Moreover, you may use the antioxidant which has both performances together. These may be used alone or in combination of two or more. Among these, it is preferable to add a phenolic antioxidant from the viewpoint of heat aging resistance and gelation suppression of the block copolymer (a).

<Crystalline material (b)>
In the present embodiment, the crystalline material (b) is a material having a crystal structure. Whether or not it is a crystalline material, that is, the presence or absence of a crystal structure, can be determined by confirming the presence or absence of an exothermic peak or endothermic peak during crystallization or crystal melting with a differential scanning calorimeter (DSC).
As the crystalline material (b), a crystalline organic material is preferable. Specific examples include paraffin, polyvinyl chloride, polyethylene, and an ethylene copolymer (ethylene / vinyl acetate copolymer, ethylene / methyl acrylate copolymer, Ethylene / ethyl acrylate copolymer, ethylene / α-olefin copolymer), polyvinyl alcohol, polyamide, saturated polyester, and derivatives thereof.

  Among these, the crystalline material (b) having a hetero atom is preferable from the viewpoint of high compatibility with asphalt (c) and high mass loss resistance and high strength reduction at the time of oil adhesion of the asphalt composition. . Among these, a crystalline material (b) having an O group or an N group is more preferable, and a crystalline material (b) having both an O group and an N group is more preferable. More preferably, 5 mol or more of heteroatoms are contained in one molecule.

<Asphalt (c)>
The asphalt that can be used in the present embodiment is not limited. For example, the asphalt can be obtained as a by-product during petroleum refining (petroleum asphalt), a natural product (natural asphalt), or a mixture of these with petroleum. And the like. Its main component is called bitumen. Specifically, straight asphalt, semi-blown asphalt, blown asphalt, tar, pitch, cutback asphalt to which oil is added, asphalt emulsion and the like can be mentioned. You may mix and use these.
Asphalt penetration (measured according to JIS-K2207) is preferably 30 or more and 300 or less, more preferably 40 or more and 200 or less, and further preferably 45 or more and 150 or less.

<Crosslinking agent>
The asphalt composition of this embodiment preferably further contains a cross-linking agent in terms of high compatibility with asphalt, high mass loss resistance at the time of oil adhesion, and high strength resistance reduction.
Examples of the crosslinking agent include sulfur, sulfur compounds, inorganic vulcanizing agents other than sulfur, oximes, nitroso compounds, polyamines, organic peroxides, resin crosslinking agents, isocyanate compounds, and polyphosphoric acid.
From the economical point of view, sulfur or a sulfur compound is preferable.
The addition amount of the crosslinking agent in the asphalt composition is preferably 0.02% by mass or more from the viewpoint of high compatibility with asphalt and high mass loss resistance and high strength reduction at the time of oil adhesion of the asphalt composition. 0.04% by mass or more is more preferable, and 0.06% by mass or more is more preferable. In addition, the amount of the crosslinking agent in the asphalt composition is preferably 1% by mass or less, preferably 0.4% by mass or less in terms of obtaining a high penetration asphalt composition and economical efficiency. More preferred is 0.2% by mass or less.

<Asphalt composition>
In the asphalt composition of the present embodiment, the content of the block copolymer (a) is from the viewpoint of obtaining an asphalt composition having a high softening point, a high mass loss resistance at the time of oil adhesion, and a high strength resistance reduction. 1.0 mass% or more is essential. 1.5 mass% or more is preferable. 2.0 mass% or more is more preferable, and 3.0 mass% or more is further more preferable.
On the other hand, the content of the block copolymer (a) is essentially 15.0% by mass or less from the viewpoint of workability and economical efficiency of the asphalt composition. 10.0 mass% or less is preferable and 8.0 mass% or less is more preferable. 6.0 mass% or less is further more preferable, and 4.5 mass% or less is most preferable.

  In the asphalt composition of this embodiment, the content of the crystalline material (b) is from the viewpoint of obtaining an asphalt composition having a high softening point, a high mass loss resistance at the time of oil adhesion, and a high strength reduction. It is 5 mass% or more, and 1.0 mass% or more is preferable. 1.5 mass% or more is more preferable. On the other hand, from the viewpoint of obtaining an asphalt composition having high elongation and high penetration, the content of the crystalline material (b) is 10% by mass or less, and preferably 8.0% by mass or less. 6.0 mass% or less is more preferable, 4.0 mass% or less is further more preferable, and 2.0 mass% or less is the most preferable.

From the viewpoint of obtaining an asphalt composition having a high mass loss resistance and a high strength reduction when oil is adhered, the contents of the block copolymer (a) and the crystalline material (b) preferably satisfy the following relational expression. .
((Content of block copolymer (a)) × 0.5) / (Content of crystalline material (b))> 1
More preferably, ((content of block copolymer (a)) × 0.5) / (content of crystalline material (b)) is 1.1 or more.

In the asphalt composition of the present embodiment, the content of asphalt (c) is 80% by mass or more in terms of road workability and economical efficiency. 90 mass% or more is more preferable, and 93 mass% or more is further more preferable. On the other hand, the content of asphalt (c) is preferably 98% by mass or less from the viewpoint of obtaining an asphalt composition having a high softening point, a high mass loss loss at the time of oil adhesion, and a high strength reduction. 97 mass% or less is more preferable, and 96 mass% or less is the most preferable.
The asphalt composition of the present embodiment may contain other polymers in addition to the block copolymer (a) and the crystalline material (b) described above. Examples of other polymers include, but are not limited to, natural rubber, polyisoprene rubber, polybutadiene rubber, styrene butadiene rubber, chloroprene rubber, acrylic rubber, and nitrile rubber.

In this embodiment, arbitrary petroleum resins can be mix | blended with an asphalt composition as needed.
Furthermore, in this embodiment, arbitrary additives can be mix | blended with an asphalt composition as needed. The type of additive is not particularly limited as long as it is generally used for blending thermoplastic resins and rubber-like polymers. For example, calcium carbonate, magnesium carbonate, magnesium hydroxide, calcium sulfate, barium sulfate, silica, clay, talc, mica, wollastonite, montmorillonite, zeolite, alumina, titanium oxide, magnesium oxide, zinc oxide, slug wool, glass fiber Inorganic fillers such as carbon black, pigments such as iron oxide, lubricants such as stearic acid, behenic acid, zinc stearate, calcium stearate, magnesium stearate, ethylene bisstearamide, mold release agents, paraffinic process oil, Softeners and plasticizers such as naphthenic process oil, aromatic process oil, paraffin, organic polysiloxane, mineral oil, hindered phenol antioxidant, antioxidant such as phosphorus heat stabilizer, hindered amine light Refining agents, benzotriazole-based UV absorbers, flame retardants, antistatic agents, organic fibers, glass fibers, carbon fibers, metal whiskers and other reinforcing agents, colorants, other additives or mixtures thereof, etc. "(Edited by Rubber Digest, Japan).
There is no restriction | limiting in particular regarding the quantity of an additive, Although it can select suitably, Usually, it is 50 mass parts or less with respect to 100 mass parts of asphalt (c).

<Method for producing asphalt composition>
There is no particular limitation regarding the method for producing the asphalt composition of the present embodiment. Further, the conditions for stirring the components such as the block copolymer (a) and the asphalt (c) are not particularly limited, but are performed at a temperature of 160 ° C. to 200 ° C. (usually around 180 ° C.). The stirring time is preferably 30 minutes to 6 hours, more preferably 2 to 3 hours. The stirring speed may be selected as appropriate depending on the apparatus to be used, but is usually from 100 rpm to 8,000 rpm.

<Asphalt mixture>
The asphalt mixture of the present embodiment includes the asphalt composition of the present embodiment and an aggregate.
There are no limitations on aggregates, and for example, any aggregate for paving as described in the “Asphalt Paving Guidelines” published by the Japan Road Association can be used. , Gravel, steel slag, etc. In addition, asphalt-coated aggregates and recycled aggregates obtained by coating these aggregates with asphalt can also be used. Other similar granular materials such as artificial sintered aggregate, sintered foam aggregate, artificial lightweight aggregate, ceramic grains, loxobite, aluminum grains, plastic grains, ceramics, emery, construction waste, fibers, etc. may be used. it can.

Aggregates are generally classified into coarse aggregates, fine aggregates, and fillers.
Coarse aggregate is an aggregate that remains on the 2.36 mm sieve, and is generally No. 7 crushed stone with a particle size range of 2.5-5 mm, No. 6 crushed stone with a particle size range of 5-13 mm, and a particle size range of 13-20 mm There are types such as No. 5 crushed stone, and further No. 4 crushed stone having a particle size range of 20 to 30 mm. In the present invention, an aggregate obtained by mixing one or more kinds of coarse aggregates having various particle size ranges. Alternatively, a synthesized aggregate or the like can be used. These coarse aggregates may be coated with about 0.3 to 1% by weight of straight asphalt with respect to the aggregates.

Fine aggregate means an aggregate that passes through a 2.36 mm sieve and stops at a 0.075 mm sieve. For example, river sand, hill sand, mountain sand, sea sand, screenings, crushed stone dust, silica sand, artificial Examples include sand, glass cullet, foundry sand, and recycled aggregate crushed sand.
Fillers pass through a 0.075 mm sieve and include, for example, screenings filler, stone powder, slaked lime, cement, incinerator ash, clay, talc, fly ash, carbon black, etc. Even rubber powder, cork powder, wood powder, resin powder, fiber powder, pulp, artificial aggregate, etc. can be used as a filler as long as it passes through a 0.075 mm sieve. it can.
Coarse aggregates, fine aggregates, or fillers may be used alone, but are generally used in a mixture of one or more.

The content of the aggregate in the asphalt mixture is preferably in the range of 85% by mass or more and 98% by mass or less from the viewpoint of obtaining an asphalt composition having a high mass loss loss when oil adheres and a high strength reduction. 97 mass% or more and 90 mass% or less are preferable.
Although there is no restriction | limiting in particular regarding the manufacturing method of an asphalt mixture, Usually, the mixing temperature of an asphalt composition and an aggregate is mixed in the range of 120 to 200 degreeC.

  EXAMPLES Hereinafter, although an Example demonstrates this invention concretely, this invention is not limited to these Examples at all.

<Method for producing block copolymer>
(Hydrogenation catalyst)
Charge 1 L of dried and purified cyclohexane to a nitrogen-substituted reaction vessel, add 100 mmol of bis (cyclopentadienyl) titanium dichloride, add an n-hexane solution containing 200 mmol of trimethylaluminum with sufficient stirring, and bring it to room temperature. For about 3 days to obtain a hydrogenation catalyst.

(Block copolymer 1)
Polymerization was carried out by the following method using a stirring apparatus having an internal volume of 10 L and a tank reactor with a jacket.
After adding 20 mass parts of cyclohexane to the reactor and adjusting the temperature to 70 ° C., 0.055 mass of n-butyl lithium is added to 100 mass parts of all monomers (total amount of butadiene monomer and styrene monomer charged into the reactor). Part, N, N, N ′, N′-tetramethylethylenediamine (hereinafter referred to as TMEDA) is added in an amount of 0.35 mol per 1 mol of n-butyllithium, and then 10 parts by mass of styrene as a monomer. (Monomer concentration 20% by mass) was added over about 3 minutes, and the reaction was carried out for 30 minutes while adjusting the reactor internal temperature to about 70 ° C.

Next, a cyclohexane solution containing 59 parts by mass of butadiene (monomer concentration of 20% by mass) and a cyclohexane solution containing 21 parts by mass of styrene (monomer concentration of 22% by mass) were continuously applied at a constant rate over 20 minutes and 10 minutes, respectively. Was fed to the reactor and then reacted for 30 minutes. During this time, the reactor internal temperature was adjusted to about 70 ° C.
Thereafter, a cyclohexane solution containing 10 parts by mass of styrene as a monomer (monomer concentration 20% by mass) is added over about 3 minutes, while adjusting the reactor internal temperature to about 70 ° C. and the reactor internal pressure to 0.30 MPa. The polymer was obtained by reacting for 30 minutes.

Next, the obtained polymer was subjected to a hydrogenation reaction using the hydrogenation catalyst. After completion of the reaction, methanol was added, and then octadecyl-3- (3,5-di-t-butyl-4-hydroxyphenyl) propionate as a stabilizer was added in an amount of 0.3% by mass based on the mass of the polymer.
The resulting hydrogenated block copolymer 1 has a styrene and styrene block content of 20% by mass, a hydrogenation rate of double bonds in the conjugated diene monomer unit of 85 mol%, a weight average molecular weight of 200,000, and a tan δ peak. The temperature was −30 ° C.

(Block copolymer 2)
Polymerization was carried out by the following method using a stirring apparatus having an internal volume of 10 L and a tank reactor with a jacket.
After charging 20 parts by mass of cyclohexane into the reactor and adjusting the temperature to 70 ° C., n-butyllithium is 0.085 parts by mass with respect to 100 parts by mass of all monomers (total amount of butadiene monomer and styrene monomer charged into the reactor). Part, N, N, N ′, N′-tetramethylethylenediamine (hereinafter referred to as TMEDA) is added in an amount of 0.35 mol to 1 mol of n-butyllithium, and then a cyclohexane solution containing 20 parts by mass of styrene as a monomer. (Monomer concentration 20% by mass) was added over about 3 minutes, and the reaction was carried out for 30 minutes while adjusting the reactor internal temperature to about 70 ° C.
Next, a cyclohexane solution containing 59 parts by mass of butadiene (monomer concentration of 20% by mass) and a cyclohexane solution containing 21 parts by mass of styrene (monomer concentration of 22% by mass) were continuously applied at a constant rate over 20 minutes and 10 minutes, respectively. Was fed to the reactor and then reacted for 30 minutes. During this time, the reactor internal temperature was adjusted to about 70 ° C.
Thereafter, tetraglycidyl-1,3-bisaminomethylcyclohexane was added as a coupling agent.
Next, the obtained polymer was subjected to a hydrogenation reaction using the hydrogenation catalyst. After completion of the reaction, methanol was added, and then octadecyl-3- (3,5-di-t-butyl-4-hydroxyphenyl) propionate as a stabilizer was added in an amount of 0.3% by mass based on the mass of the polymer.
The resulting hydrogenated block copolymer 2 has a styrene and styrene block content of 20% by mass, a hydrogenation rate of double bonds in the conjugated diene monomer unit of 80 mol%, a weight average molecular weight of 250,000, and a tan δ peak. The temperature was -28 ° C.

(Block copolymer 3)
Polymerization was carried out by the following method using a stirring apparatus having an internal volume of 10 L and a tank reactor with a jacket.
After adding 20 mass parts of cyclohexane to the reactor and adjusting the temperature to 70 ° C., 0.055 mass of n-butyl lithium is added to 100 mass parts of all monomers (total amount of butadiene monomer and styrene monomer charged into the reactor). Then, a cyclohexane solution containing 15 parts by mass of styrene as a monomer (monomer concentration: 20% by mass) was added over about 3 minutes, and the reaction was carried out for 30 minutes while adjusting the reactor internal temperature to about 70 ° C.
Next, a cyclohexane solution (monomer concentration 20% by mass) containing 70 parts by mass of butadiene was continuously supplied to the reactor at a constant rate for 30 minutes, and then reacted for 30 minutes. During this time, the reactor internal temperature was adjusted to about 70 ° C.
Thereafter, a cyclohexane solution containing 15 parts by mass of styrene as a monomer (monomer concentration 20% by mass) was added over about 3 minutes, while adjusting the reactor internal temperature to about 70 ° C. and the reactor internal pressure to 0.30 MPa. The polymer was obtained by reacting for 30 minutes.

Next, 0.3% by mass of octadecyl-3- (3,5-di-t-butyl-4-hydroxyphenyl) propionate as a stabilizer was added to the obtained polymer based on the mass of the polymer.
The obtained non-hydrogenated block copolymer 3 had a styrene and styrene block content of 30% by mass, a weight average molecular weight of 200,000, and a tan δ peak temperature of −72 ° C.

<Method for evaluating block copolymer>
(Vinyl content and hydrogenation rate in block copolymer)
The vinyl content in the block copolymers 1 and 2 and the hydrogenation rate of double bonds in the conjugated diene monomer unit were measured under the following conditions by nuclear magnetic resonance spectrum analysis (NMR).
In addition, the block copolymers 1 and 2 were precipitated and recovered by precipitation in a large amount of methanol in the reaction solution after the hydrogenation reaction. Subsequently, the block copolymers 1 and 2 were extracted with acetone, and the extract was vacuum-dried and used as a sample for 1H-NMR measurement. The conditions for 1H-NMR measurement are described below.

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

(Content of vinyl aromatic monomer unit (styrene unit))
A certain amount of block copolymers 1 to 3 are dissolved in chloroform, and an absorption wavelength caused by the vinyl aromatic compound component (styrene) in the solution is obtained using an ultraviolet spectrophotometer (manufactured by Shimadzu Corporation, UV-2450). The peak intensity at (262 nm) was measured. From the obtained peak intensity, the content of vinyl aromatic monomer units (styrene units) was calculated using a calibration curve.

(Content of polymer block (A) mainly composed of vinyl aromatic monomer unit in block copolymer)
I. M.M. Kolthoff, et al. , J. et al. Polym. Sci. , 1946, Vol. 1, p. The content of the polymer block (A) mainly composed of vinyl aromatic monomer units was measured using the following polymer decomposition solution by the osmium tetroxide method described in No. 429.
(Measurement condition)
Measurement sample: Extracted product of block copolymers 1 to 3 before hydrogenation Polymer decomposition solution: solution of 0.1 g of osmic acid dissolved in 125 mL of tertiary butanol

(Weight average molecular weight of block copolymer)
The weight average molecular weights of the block copolymers 1 to 3 were measured by gel permeation chromatography (GPC) under the following conditions.
(Measurement condition)
Measuring device: LC-10 (manufactured by Shimadzu Corporation)
Column: TSKgelGMHXL (4.6 mm ID × 30 cm), 2 solvents: Tetrahydrofuran Calibration curve sample: commercially available standard polystyrene (manufactured by Tosoh Corporation), 10-point measurement

(Tan δ peak temperature of block copolymer)
The dynamic viscoelastic spectrum was measured by the following method to obtain the peak temperature of the loss coefficient tan δ.
First, the block copolymers 1 to 3 were formed into a sheet having a thickness of 2 mm, and then cut into a size having a width of 10 mm and a length of 35 mm to obtain a measurement sample.
A measurement sample is set in the twist type geometry of the device ARES (trade name, manufactured by TI Instrument Co., Ltd.), the effective measurement length is 25 mm, the strain is 0.5%, the frequency is 1 Hz, and the measurement range is −100 ° C. The relationship between temperature and tan δ = loss elastic modulus E ″ / storage elastic modulus E ′ was measured from 10 ° C. to 10 ° C. under the temperature rising rate of 3 ° C./min. When there are two or more tan δ peak temperatures in the range of −100 ° C. to 10 ° C., the peak temperature with the highest peak height was defined as the tan δ peak temperature.

<Method for producing asphalt composition>
500 g of straight asphalt 60-80 [manufactured by Shin Nippon Oil Co., Ltd.] was put into a 750 mL metal can, and the metal can was sufficiently immersed in an oil bath at 180 ° C.
Next, the block copolymer, crystalline material (ethylene / vinyl acetate copolymer (EVA), polyamide resin) in the amount (mass%) shown in Table 1 while stirring the molten asphalt at a rotational speed of 4000 rpm. And wax) and other components (sulfur) were added to the asphalt, stirred for 120 minutes after the addition, and cured at 160 ° C. for 24 hours to prepare an asphalt composition.
In addition, the following were used as an ethylene / vinyl acetate copolymer (EVA), a polyamide resin, and a wax.
-Ethylene / vinyl acetate copolymer (EVA): EV460 (Mitsui / DuPont Polychemical Co., Ltd., trade name, VA content 19%, hetero atom 5 mol or more)
Polyamide resin: Haridimer 250 (Harima Kasei Co., Ltd., trade name, softening point 135 ° C., containing 5 mol or more of hetero atoms)
Wax: Sasobit (manufactured by Sasol, trade name, hydrocarbon wax)
The above EVA, polyamide resin, and wax were confirmed to have a crystal structure by a differential scanning calorimeter (DSC).

<Method for producing asphalt mixture>
For the aggregate, the blending ratio of No. 6 crushed stone / No. 7 crushed stone / sand crushed / fine sand / stone powder, 36/19/27/12/6%, asphalt composition 5.5 mass%, aggregate 94.5 mass % Was mixed at 180 ° C. to obtain an asphalt mixture.

<Evaluation of asphalt mixture>
(Evaluation method of oil resistance (1) Mass loss rate after oil immersion)
An asphalt mixture was formed into a wheel tracking specimen, and the pre-oil immersion mass of a specimen having a diameter of 10 cm was measured. The specimen was immersed in kerosene at room temperature for 48 hours, and the specimen was taken out and placed on a filter paper at room temperature. The specimen mass was measured after standing for 24 hours, and the mass loss rate from the initial stage was measured.
Evaluation was made into ◎, ○, Δ, and × from the good order.
Mass loss rate ≦ 1.0%: ◎
1.0% <mass loss rate ≦ 2.0%: ○ 2.0% <mass loss rate ≦ 3.0%: Δ
3.0% <mass loss rate: ×

(Evaluation method of oil resistance (2) Marshall strength residual ratio after oil immersion)
As in the oil resistance evaluation method (1), after immersion in oil, after immersion in hot water at 60 ° C. for 40 minutes, a Marshall strength test was performed and compared with the strength before immersion in oil.
Oil-immersed residual strength rate (%)
= (Marshall strength after oil immersion / Marshall strength before oil immersion) × 100.
Evaluation was made into ◎, ○, Δ, and × from the good order.
85% <residual hardness ratio: ◎
80% <residual strength rate ≦ 85%: ○ 70% <residual strength rate ≦ 80%: Δ
Mass loss rate ≦ 70: ×

[Examples 1-5], [Comparative Examples 1-5]
Table 1 shows the compositions of the asphalt compositions of Examples 1 to 5 and Comparative Examples 1 to 5 and the evaluation results of the asphalt mixture using the compositions.
From Table 1 below, it can be seen that the asphalt composition of the present invention exhibits a high mass loss resistance and a high strength reduction at the time of oil adhesion when an asphalt mixture is used.

  The asphalt composition of the present invention can be used in fields such as road pavement, roofing and waterproof sheets, and sealants, and can be suitably used particularly in the field of road pavement. It is particularly suitable for road paving that requires oil resistance.

Claims (9)

An asphalt composition containing 1 to 15% by mass of a block copolymer (a), 0.5 to 10% by mass of a crystalline material (b) and 80% by mass or more of asphalt (c),
The block copolymer (a) is a polymer containing a conjugated diene monomer unit and a vinyl aromatic monomer unit,
The tan δ peak temperature obtained by the dynamic viscoelasticity test of the block copolymer (a) is in the range of −50 ° C. to 0 ° C.,
Asphalt composition. The block copolymer (a) is a polymer block (A) mainly composed of a vinyl aromatic monomer unit, and a copolymer block (B) containing a conjugated diene monomer unit and a vinyl aromatic monomer unit. )
The asphalt composition of Claim 1 whose content of the said polymer block (A) in a block copolymer (a) is 10 to 40 mass%.   The asphalt composition of Claim 1 or 2 whose content of the vinyl aromatic monomer unit in a block copolymer (a) is 20 mass% or more and 60 mass% or less.   The asphalt composition as described in any one of Claims 1-3 in which 30 mol% or more of the double bond in the conjugated diene monomer unit in a block copolymer (a) is hydrogenated.   The asphalt composition according to any one of claims 1 to 4, wherein the crystalline material (b) has a hetero atom. The asphalt composition as described in any one of Claims 1-5 in which content of the said block copolymer (a) and the said crystalline material (b) satisfy | fills the following relational expression.
(Content of block copolymer (a)) × 0.5 / (Content of crystalline material (b))> 1   Furthermore, the asphalt composition as described in any one of Claims 1-6 containing a crosslinking agent.   The block copolymer (a) has at least one functional group selected from a hydroxyl group, an acid anhydride group, an epoxy group, an amino group, an amide group, a silanol group, and an alkoxysilane group. The asphalt composition according to any one of 7.   An asphalt mixture comprising the asphalt composition according to any one of claims 1 to 8 and an aggregate.