Asphalt composition, masterbatch, and method for producing the asphalt composition

Abstract

To provide an asphalt composition which is excellent in a softening point, elongation and workability, and has sufficient high-temperature storage stability, rutting resistance and low-temperature cracking resistance.SOLUTION: An asphalt composition contains asphalt, a block copolymer and a resin and / or rubber, and satisfies (i) to (iii). (i) The asphalt is 85-99 pts.mass. (ii) The block copolymer contains a polymer block (A) mainly including a vinyl aromatic monomer unit, and a polymer block (B) including a conjugated diene monomer unit and a vinyl aromatic monomer unit, and the block copolymer is 0.1-15 pts.mass. (iii) The resin is a resin other than the block copolymer, and is an amorphous resin having Tg of 170°C or lower or a crystalline rein having a melting point of 170°C or lower, a content thereof is 0.1 or more and less than 15 pts.mass, and a content of the rubber is 0.1 or more and less than 15 pts.mass. (iv) A total content of the block copolymer, and the resin and / or the rubber is 0.1 or more and 15 pts.mass or less.SELECTED DRAWING: None

Description

[Technical Field]

[0001] The present invention relates to an asphalt composition, a masterbatch, and a method for producing an asphalt composition. [Background technology]

[0002] Conventionally, asphalt compositions have been widely used for applications such as road paving, waterproofing sheets, sound insulation sheets, and roofing. When using the aforementioned asphalt compositions for various applications, many attempts have been made to improve their properties by adding various polymers to the asphalt. Examples of the polymers used include polyethylene, polypropylene, ethylene-vinyl acetate copolymer, ethylene-ethyl acrylate copolymer, rubber latex, and block copolymers consisting of conjugated dienes and vinyl aromatic hydrocarbons (see, for example, Patent Documents 1 to 3).

[0003] In recent years, efforts to promote sustainable development have been made internationally. Among these, the problem of environmental pollution caused by waste plastics is one of the most serious issues, and the development of effective recycling technologies is needed. Currently, recycling technologies for waste plastics include material recycling, which reuses waste as new raw materials; chemical recycling, which returns waste to raw materials through chemical treatment; and thermal recycling, which recovers thermal energy during incineration. However, the majority of recycling is thermal recycling, and the environmental problems caused by greenhouse gases generated during incineration are becoming even more serious. On the other hand, in recent years, the use of waste plastics as asphalt paving materials has attracted attention, and waste plastics are being used as additives utilizing the chemical recycling of polyethylene terephthalate (see, for example, Patent Document 4) and as a substitute material for aggregates (see, for example, Patent Document 5). [Prior art documents] [Patent Documents]

[0004]

Patent Document 1

Patent Document 2

Patent Document 3

Patent Document 4

Patent Document 5

Summary of the Invention

Problems to be Solved by the Invention

[0005] However, in the technologies disclosed in Patent Documents 1 to 3, sufficient storage stability, low-temperature crack resistance, and rutting resistance have not yet been obtained, and there is a problem that further improvement is required. In addition, in the technology disclosed in Patent Document 4, no detailed study has been conducted to obtain practically sufficient characteristics when adding recycled plastics with unstable physical properties in which a plurality of resins are mixed to an asphalt composition, and there is still a problem that there is room for improvement. Furthermore, the asphalt composite disclosed in Patent Document 5 has a problem that since waste plastic is added as an aggregate, there is a risk of cracking in a low-temperature environment and generation of microplastics during deterioration.

[0006] Therefore, in view of the problems of the above-described conventional technologies, the present invention aims to provide an asphalt composition and a method for producing the same, which contain asphalt, a block copolymer, and a resin and / or rubber, have a high softening point, elongation, low melt viscosity, excellent processability, and further have sufficient high-temperature storage stability, rutting resistance, and low-temperature crack resistance.

Means for Solving the Problems

[0007] As a result of intensive studies to solve the problems of the prior art described above, the inventors of the present invention have found that, in an asphalt composition containing asphalt, a block copolymer, and a resin and / or rubber, by specifying the content of asphalt, the content of the block copolymer, the physical properties and content of the resin, and the total content of the block copolymer and the resin and / or rubber, the problems of the prior art described above can be solved, and the present invention has been completed. That is, the present invention is as follows.

[0008] 〔1〕 85 to 99 parts by mass of asphalt, 0.1 to 15 parts by mass of a block copolymer, less than 0 to 15 parts by mass of a resin and / or rubber, having a step of mixing, The block copolymer has a polymer block (A) mainly composed of vinyl aromatic monomer units and a polymer block (B) containing conjugated diene monomer units and vinyl aromatic monomer units. The resin is a resin other than the block copolymer, and is an amorphous resin having a glass transition temperature of 170°C or lower or a crystalline resin having a melting point of 170°C or lower. The rubber is a vulcanizate of at least one rubber selected from the group consisting of polybutadiene rubber, styrene-butadiene rubber, natural rubber, and polyisoprene rubber. the law of nature, As a step preceding the mixing step, The process includes kneading the block copolymer with the resin and / or rubber to produce a masterbatch. The content of the block copolymer in the masterbatch is set to 10% by mass or more and 90% by mass or less. The resin content in the masterbatch is set to be 10% by mass or more and 90% by mass or less. The rubber content in the masterbatch is set to be 10% by mass or more and 90% by mass or less. A method for producing an asphalt composition. 〔2〕 The method for producing an asphalt composition according to the above, wherein the resin contains a polyolefin and a polar resin. 〔1〕 The method for producing an asphalt composition according to the above, wherein the resin contains 70% by mass or more of a polyolefin and 30% by mass or less of a polar resin. 〔3〕 The method for producing an asphalt composition according to the above, wherein the resin contains 70% by mass or more of a polyolefin and 30% by mass or less of a polar resin.〔2〕 A method for producing the asphalt composition described above. 〔4〕 The resin is the crushed material of the film. [1] to [3] A method for producing an asphalt composition as described in any one of the following. 〔5〕 The film is a polyolefin single-layer film, or a multilayer film having a layer made of ethylene vinyl acetate copolymer and a layer made of polyethylene. 〔4〕 A method for producing the asphalt composition described above. 〔6〕 The rubber is at least one selected from the group consisting of rubber powder, fine rubber powder, rubber pellets, and rubber powder as defined in JIS K6200-2019. [1] to [5] A method for producing an asphalt composition as described in any one of the following. 〔7〕 The rubber is vulcanized rubber powder obtained by crushing used tires to a particle size of 5 mm or less. [1] to [6] A method for producing an asphalt composition as described in any one of the following. 〔8〕 In the mixing step, the mixture is heated to 180°C or below. [1] to [7] A method for producing an asphalt composition as described in any one of the following. 〔9〕 The asphalt has an asphaltene content of 15% by mass or more and 25% by mass or less, a resin content of 15% by mass or more and 30% by mass or less, and an aromatic content of 35% by mass or more and 60% by mass or less, [1] to [8] A method for producing an asphalt composition as described in any one of the following. [Effects of the Invention]

[0009] According to the present invention, it is possible to provide an asphalt composition and a method for producing the same, which has a high softening point and elongation, low melt viscosity and excellent processability, as well as sufficient high-temperature storage stability, rutting resistance and low-temperature crack resistance. [Modes for carrying out the invention]

[0010] The embodiments for carrying out the present invention (hereinafter referred to as "this embodiment") will be described in detail below. The following embodiments are illustrative for explaining the present invention and are not intended to limit the present invention to the following. The present invention can be implemented in various modifications within the scope of its gist.

[0011] [Asphalt composition] The asphalt composition of this embodiment contains asphalt, a block copolymer, and a resin and / or rubber, and satisfies the following conditions (i) to (iii). In this specification, the term "resin" constituting the asphalt composition refers to a polymer that is thermoplastic, melts upon heating, and can be remolded. Among these resins, a copolymer having both hard and soft parts that exhibits rubber elasticity at room temperature through pseudo-crosslinking by aggregation of the hard parts and functions as a compatibilizer with asphalt is called a "block copolymer." On the other hand, in this specification, the "rubber" constituting the asphalt composition has a structure in which at least some of the double bonds in the molecule of a polymer containing conjugated diene monomer units are crosslinked. Typical examples include vulcanized products of polybutadiene, polyisoprene, styrene-butadiene (SBR), and natural rubber. These rubbers are used as tire raw materials in a state mixed with fillers such as carbon and silica, and process oils, and the crushed tire material is a mixture containing fillers, etc., but by using this mixture as a raw material for the asphalt composition, it becomes possible to make effective use of resources. <Condition (i)> The asphalt content in the asphalt composition is 85 parts by mass or more and 99 parts by mass or less. <Condition (ii)> The block copolymer comprises a polymer block (A) mainly composed of vinyl aromatic monomer units and a polymer block (B) containing conjugated diene monomer units and vinyl aromatic monomer units, and the content of the block copolymer in the asphalt composition is 0.1 parts by mass or more and 15 parts by mass or less. <Condition (iii)> The resin is a resin other than the block copolymer, and is an amorphous resin with a glass transition temperature of 170°C or less, or a crystalline resin with a melting point of 170°C or less, and the content of the resin in the asphalt composition is 0.1 parts by mass or more and less than 15 parts by mass. The amount of the rubber in the asphalt composition is 0.1 parts by mass or more and less than 15 parts by mass. <Condition (iv)> The total content of the block copolymer and resin and / or rubber in the asphalt composition is 0.1 parts by mass or more and 15 parts by mass or less.

[0012] (Block copolymer) The asphalt composition of this embodiment contains a block copolymer. The block copolymer is a polymer containing conjugated diene monomer units and vinyl aromatic monomer units, and comprises a polymer block (A) mainly composed of vinyl aromatic monomers and a copolymer block (B) containing conjugated diene monomer units and vinyl aromatic monomer units.

[0013] In this specification, a conjugated diene monomer unit is a polymer unit formed by a conjugated diene compound within a polymer as a result of the polymerization of a conjugated diene compound. Conjugated diene compounds are diolefins having a pair of conjugated double bonds. Examples of conjugated diene compounds include, but are not limited to, 1,3-butadiene, 2-methyl-1,3-butadiene (isoprene), 2,3-dimethyl-1,3-butadiene, 1,3-pentadiene, 2-methyl-1,3-pentadiene, and 1,3-hexadiene. Preferably, the compound is 1,3-butadiene and isoprene. The conjugated diene compound may be used alone or in combination of two or more.

[0014] In this specification, a vinyl aromatic monomer unit is a polymer unit formed by vinyl aromatic compounds within a polymer as a result of the polymerization of vinyl aromatic compounds. Examples of vinyl aromatic compounds include, but are not limited to, styrene, α-methylstyrene, p-methylstyrene, divinylbenzene, 1,1-diphenylethylene, N,N-dimethyl-p-aminoethylstyrene, and N,N-diethyl-p-aminoethylstyrene. One vinyl aromatic compound may be used alone, or two or more may be used in combination.

[0015] The inclusion of vinyl aromatic monomer units in the block copolymer results in a high softening point for the asphalt composition and excellent rutting resistance of the asphalt mixture, meeting the Japan Modified Asphalt Association Standard (JAMMAS-01).

[0016] The content of vinyl aromatic monomer units in the block copolymer is preferably 20% to 60% by mass, more preferably 25% to 55% by mass, even more preferably 30% to 50% by mass, and even more preferably 35% to 45% by mass, based on 100% by mass of the block copolymer. The content of vinyl aromatic monomer units in the block copolymer is 20% by mass or more, which provides excellent recovery after tensile strength. Furthermore, when the asphalt composition of this embodiment is used for construction in high-temperature regions, a highly durable asphalt composition can be obtained. Furthermore, having a vinyl aromatic monomer unit content of 60% by mass or less improves the flexibility of the asphalt composition and results in high elongation. The content of vinyl aromatic monomer units in the block copolymer can be controlled within the above numerical range by adjusting the amount of vinyl aromatic compound added during the polymerization process.

[0017] From the viewpoint of elongation, high-temperature storage stability, separation stability, heat aging resistance, recovery after tensile strength, and aggregate peel resistance of the asphalt composition of this embodiment, the content of vinyl aromatic monomer units in the block copolymer is more preferably 20% by mass or more, even more preferably 25% by mass or more, even more preferably 30% by mass or more, and even more preferably 35% by mass or more. From the viewpoint of elongation, flexibility, separation stability, flexibility, recovery after tension, and aggregate peel resistance of the asphalt composition, 60% by mass or less is preferred, 55% by mass or less is more preferred, 50% by mass or less is even more preferred, 50% by mass or less is even more preferred, and 45% by mass or less is even more preferred. From the viewpoint of balancing the softening point and elongation of the asphalt composition, the content of vinyl aromatic monomer units in the block copolymer is preferably 25% by mass or more and 55% by mass or less, more preferably 30% by mass or more and 55% by mass or less, and even more preferably 30% by mass or more and 50% by mass or less. The content of vinyl aromatic monomer units in the block copolymer can be measured by the method described in the examples below.

[0018] When a block copolymer is hydrogenated, the content of vinyl aromatic monomer units in the block copolymer is approximately equal to the content of vinyl aromatic monomer units in the polymer before hydrogenation. Therefore, the content of vinyl aromatic monomer units in a hydrogenated block copolymer may be determined as the content of vinyl aromatic monomer units before hydrogenation.

[0019] The polymer block (A) that constitutes the block copolymer is a block mainly composed of vinyl aromatic monomer units. Here, "primarily composed of vinyl aromatic monomer units" means that the polymer block (A) contains vinyl aromatic monomer units in an amount of 60% by mass or more, preferably 80% by mass or more, more preferably 90% by mass or more, and even more preferably 95% by mass or more. There are no particular restrictions on the upper limit, but it is preferable that it be 100% by mass or less, and more preferably 99% by mass or less. The amount of vinyl aromatic monomer units contained in the polymer block (A) is preferably more than 95% by mass and 100% by mass or less, more preferably 96% by mass or more and 100% by mass or less, and even more preferably 97% by mass or more and 100% by mass or less.

[0020] The content of polymer blocks (A) in the block copolymer is preferably 10% by mass or more and 40% by mass or less based on 100% by mass of the block copolymer. When the polymer block (A) content in the block copolymer is 10% by mass or more, the cohesive force of the aromatic monomer unit blocks becomes stronger, and the softening point of the asphalt composition of this embodiment tends to be even higher than that which satisfies the modified asphalt standard. As a result, it is easier to obtain an asphalt composition that can be applied to areas where roads tend to get hotter. Furthermore, the asphalt composition of this embodiment tends to be flexible when the content of polymer blocks (A) in the block copolymer is 40% by mass or less. From the viewpoint of a higher softening point, recovery after tensile strength, and resistance to aggregate peeling, the content of polymer block (A) per 100% by mass of block copolymer is preferably 10% by mass or more, more preferably 13% by mass or more, even more preferably 16% by mass or more, and even more preferably 17% by mass or more. From the viewpoint of flexibility, high-temperature storage stability, and aggregate peelability of the block copolymer and the asphalt composition of this embodiment, the content of polymer blocks (A) in the block copolymer is preferably 40% by mass or less, more preferably 35% by mass or less, even more preferably 30% by mass or less, even more preferably 29% by mass or less, even more preferably 23% by mass or less, and particularly preferably 22% by mass or less. From the viewpoint of the softening point and high-temperature storage stability of the asphalt composition of this embodiment, the content of polymer blocks (A) in the block copolymer is preferably 15% by mass or more and 35% by mass or less, and more preferably 20% by mass or more and 30% by mass or less. If the asphalt composition of this embodiment contains the resin described above, and the resin is an olefin-based resin, then, from the viewpoint of compatibility between asphalt and olefin-based resin, the content of polymer blocks (A) in the block copolymer constituting the asphalt composition of this embodiment is preferably 55% by mass or less, and more preferably 45% by mass or less. The content of polymer block (A) in the block copolymer can be controlled within the above numerical range by adjusting polymerization conditions such as the amount of monomer added, polymerization temperature, and polymerization pressure during the polymerization process.

[0021] The content of polymer blocks (A) in a block copolymer can be determined, for example, by using the mass of vinyl aromatic polymer block components obtained by oxidative decomposition of the polymer with tertiary butyl hydroperoxide using osmium tetroxide as a catalyst (as described in IMKOLTHOFF, et.al, J. Polym. Sci. 1, p. 429 (1946)) (however, vinyl aromatic polymer block components with an average degree of polymerization of about 30 or less are excluded), and then using the following formula. Polymer block (A) content (mass%) = (mass of vinyl aromatic polymer block component / mass of block copolymer) × 100

[0022] The block copolymer constituting the asphalt composition of this embodiment may be hydrogenated. When the block copolymer is hydrogenated, the content of polymer blocks (A) is approximately equal to the content of polymer blocks (A) in the block copolymer before hydrogenation. Therefore, in this embodiment, the content of polymer blocks (A) in the block copolymer when the block copolymer is hydrogenated may be determined as the content of polymer blocks (A) before hydrogenation.

[0023] The polymer block (B) constituting the block copolymer is a polymer block containing conjugated diene monomer units and vinyl aromatic monomer units. The presence of polymer blocks (B) improves the compatibility between the block copolymer and asphalt, making it easier to achieve a high softening point that meets the modified asphalt standards. Furthermore, the presence of conjugated diene monomer units in polymer blocks (B) tends to improve the low-temperature elongation of the asphalt composition of this embodiment, thereby improving the low-temperature crack resistance of the asphalt composition. Specifically, for evaluating low-temperature elongation, the elongation measured while the asphalt composition is maintained at 10°C or 5°C can be used. The content of vinyl aromatic monomer units in polymer block (B) is preferably 10% by mass or more and less than 60% by mass, from the viewpoint of high compatibility between asphalt and the block copolymer. This allows it to be distinguished from polymer block (A). The content of vinyl aromatic monomer units in polymer block (B) is more preferably 10% by mass or more and 50% by mass or less, and even more preferably 12% by mass or more and 40% by mass or less.

[0024] In the asphalt composition of this embodiment, the content of vinyl aromatic monomer units contained in polymer block (B) is preferably 10% by mass or more, more preferably 20% by mass or more, and even more preferably 25% by mass or more, from the viewpoint of obtaining a higher (exceeding standard) softening point, high-temperature storage stability, dispersibility, separation stability, heat aging resistance, and recovery after tensile strength. Furthermore, from the viewpoint of low polymer addition amounts to the asphalt composition, separation stability of the asphalt composition, flexibility of the asphalt composition and block copolymer, weather resistance, aggregate peeling resistance, viscosity, and dispersibility, a polymer addition amount of 50% by mass or less is preferred, 40% by mass or less is more preferred, 35% by mass or less is even more preferred, and 30% by mass or less is even more preferred. The polymer block (B) is preferably a random block. Here, "random" means a state in which there are 10 or fewer consecutive vinyl aromatic monomer units in the block copolymer.

[0025] The content of polymer blocks (B) in the block copolymer is preferably 60% by mass or more and 90% by mass or less based on 100% by mass of the block copolymer. When the content of polymer blocks (B) in the block copolymer is 60% by mass or more, the solubility of the block copolymer and asphalt is improved, resulting in an asphalt composition with excellent storage stability. When the content is 90% by mass or less, the mass ratio of polymer blocks (A) increases, the cohesive force between polymer blocks (A) in the asphalt composition increases, and excellent recovery properties are obtained. From the viewpoint of extending the lifespan of roads, the content of polymer blocks (B) in the block copolymer is more preferably 65% ​​by mass or more and 85% by mass or less, and even more preferably 70% by mass or more and 80% by mass or less.

[0026] Furthermore, the blocking ratio of the block copolymer is preferably 16.6% to 96.5%, more preferably 20% to 90%, and even more preferably 25% to 85%. The block ratio can be calculated using the following formula, based on the content of vinyl aromatic monomer units (e.g., styrene content) and the content of polymer blocks (A) in the block copolymer. Content of polymer block (A) in block copolymer / Content of vinyl aromatic monomer units in block copolymer × 100 (%) From the viewpoint of balancing softening point and dispersibility, it is preferable that the block ratio be within the above numerical range.

[0027] The content of vinyl aromatic monomer units (RS) in polymer block (B) can be determined by subtracting the content of polymer block (A) mainly composed of the above vinyl aromatic monomer units (BS) from the content of vinyl aromatic monomer units (TS) in the block copolymer. Specifically, it can be calculated using the formula RS (mass%) = (TS - BS) / (100 - BS) × 100.

[0028] In block copolymers, it is preferable that the hydrogenation rate (mol%), which is the content of hydrogenated conjugated diene monomer units in the total content of conjugated diene monomer units, i.e., the hydrogenation rate of double bonds in conjugated diene monomer units, is 0 mol% or more and 100 mol% or less. In this case, the block copolymer is either unhydrogenated, or 100 mol% or less of the total content of conjugated diene monomer units is selectively hydrogenated, or 100 mol% of the total content of conjugated diene monomer units is completely hydrogenated. From the viewpoint of compatibility with the resin described later, high-temperature storage stability, and UV resistance, the block polymer is preferably hydrogenated. When the block copolymer is hydrogenated, from the viewpoint of shortening the dissolution time, the hydrogenation rate is preferably 30 mol% to 100 mol%, and more preferably 40 mol% to 100 mol%. Furthermore, from the viewpoint of penetration and recovery after tensile strength, it is preferably 50 mol% to 90 mol%, and even more preferably 60 mol% to 90 mol%. From the viewpoint of reducing the viscosity of the asphalt composition, the hydrogenation rate of the block copolymer is preferably 90 mol% or less, more preferably 88 mol% or less, even more preferably 86 mol% or less, and even more preferably 85 mol% or less. Furthermore, when adding block copolymer to asphalt, from the viewpoint of reducing the amount of block copolymer added, compatibility with resins described later, recovery after tensile strength, high heat aging resistance during storage, and aggregate peel resistance, the hydrogenation rate of the block copolymer is preferably greater than 60 mol%, more preferably 70 mol% or more, even more preferably 80 mol% or more, and even more preferably 90 mol% or more. There is no particular upper limit, but 100 mol% or less is preferred. When the resin described later is an olefin-based resin with a crystallinity of 90% or more, the hydrogenation rate of the block copolymer is preferably 60 moles or more, more preferably 70 moles or more, even more preferably 80 moles or more, even more preferably 90 moles or more, and most preferably 100 moles. Furthermore, considering the balance of compatibility between asphalt and olefin resin in light of the above, the hydrogenation rate of the block copolymer is preferably 40 moles to 95 moles, and more preferably 60 moles to 85 moles. Furthermore, from the viewpoint of viscosity, the upper limit is preferably 98 mol% or less, more preferably 96 mol% or less, and even more preferably 93 mol% or less. On the other hand, it is preferable that the block copolymer is not hydrogenated, from the viewpoint of high elongation and excellent recovery properties of the asphalt composition. In this case, the rubbery properties of the asphalt composition tend to improve due to the crosslinking reaction between the double bonds of the conjugated diene monomer units in the block copolymer and the sulfur components contained in the asphalt. The hydrogenation rate of double bonds in the conjugated diene monomer units in the block copolymer can be determined by the method described in the examples below. The hydrogenation rate of double bonds in the conjugated diene monomer units within the block copolymer can be controlled within the above numerical range by adjusting conditions such as the amount of hydrogenation, catalyst, temperature, and pressure during the hydrogenation process.

[0029] The block copolymer preferably has a peak top of loss tangent (tanδ) in the dynamic viscoelasticity spectrum in the range of -70°C to 0°C, and the value of this peak top is preferably between 0.5 and 2.0. From the viewpoint of shortening the dissolution time and softening point of the asphalt composition of this embodiment, it is more preferable that the peak top of the loss tangent (tanδ) be in the range of -55°C to -10°C, even more preferably in the range of -55°C to -15°C, even more preferably in the range of -55°C to -20°C, and even more preferably in the range of -55°C to -25°C. Furthermore, the temperature at which the peak top of the loss tangent (tanδ) of the block copolymer occurs is preferably -55°C or higher, more preferably -50°C or higher, even more preferably -45°C or higher, and even more preferably -40°C or higher, from the viewpoint of high compatibility with asphalt and softening point. Furthermore, the temperature at which the peak top of the loss tangent (tanδ) of the block copolymer occurs is preferably 0°C or lower, more preferably -10°C or lower, even more preferably -13°C or lower, and even more preferably -15°C or lower, from the viewpoint of the flexibility of the asphalt composition, recovery after tension, and resistance to aggregate taxidermy. From the viewpoint of low-temperature crack resistance during road freezing, it is preferable to set the peak top of the loss tangent (tanδ) to 0°C or below. By setting it to 0°C or below, the decrease in rubber properties of the asphalt composition during freezing can be reduced, and cracking of paved roads in winter can be suppressed.

[0030] Furthermore, when constructing roads containing the resin described later in cold regions, there is a concern that cracking may occur at low temperatures. Therefore, when considering construction in cold regions, it is preferable to set the temperature at which the peak of the loss tangent (tanδ) of the block copolymer occurs to be lower than the minimum temperature expected for roads in that region. Specifically, it is preferable that the temperature at which the peak of the loss tangent (tanδ) occurs is -10°C or lower, more preferably -20°C or lower, and even more preferably -30°C or lower. By setting the peak of the loss tangent (tanδ) of the block copolymer to -30°C or lower, the low-temperature elongation is further improved, and crack resistance in low-temperature environments can be further enhanced in environments where many roads are constructed. In this way, the rubbery properties of the asphalt composition of this embodiment can be maintained even in cold regions below -30°C, and cracking in extremely low-temperature environments (below -30°C) can be suppressed.

[0031] Furthermore, from the viewpoint of shortening the dissolution time of the asphalt composition of this embodiment, the peak top value of the loss tangent (tanδ) is preferably 0.5 or more and 2.0 or less, more preferably 0.5 or more and 1.47 or less, even more preferably 0.5 or more and 1.44 or less, and even more preferably 0.5 or more and 1.41 or less. From the viewpoint of shortening the dissolution time of the asphalt composition of this embodiment and its resistance to aggregate peeling, the peak top value is preferably 0.5 or higher, more preferably 0.7 or higher, even more preferably 0.9 or higher, and even more preferably 1.0 or higher. Furthermore, from the viewpoint of shortening the dissolution time of the asphalt composition of this embodiment and its resistance to aggregate peeling, the peak top value is preferably 2.0 or less, more preferably 1.6 or less, even more preferably 1.5 or less, even more preferably 1.47 or less, even more preferably 1.44 or less, particularly preferably 1.41 or less, even more preferably 1.4 or less, and most preferably 1.3 or less. Furthermore, asphalt compositions containing the resin described later are susceptible to cracking due to impacts from the passage of large vehicles, etc. Therefore, from the viewpoint of providing impact absorption, the peak top value of the block copolymer is preferably 0.5 or higher, more preferably 0.7 or higher, even more preferably 0.9 or higher, and even more preferably 1.0 or higher.

[0032] The dynamic viscoelastic spectrum of the block copolymer can be measured by the method described in the examples below.

[0033] In block copolymers, the ratio of vinyl aromatic monomer units to conjugated diene monomer units in the polymer block (B) can be adjusted to control the peak top of the loss tangent (tanδ) in the range of -70 to 0°C, preferably in the range of -55 to -10°C. Furthermore, the peak value of the loss tangent (tanδ) tends to increase when the randomness of polymer block (B) is increased, the content of vinyl aromatic monomer units in polymer block (B) is decreased, the amount of vinyl bond is increased, the hydrogenation rate is increased, and the content of polymer block (A) is decreased. Moreover, by controlling the temperature and the addition time of each monomer during the polymerization of polymer block (B), the peak value of the loss tangent (tanδ) can be controlled to be between 0.5 and 2.0, preferably between 0.5 and 1.5. Specifically, by setting the reactor temperature in the polymerization step of the block copolymer within the range of 56 to 90°C, the reactor pressure within the range of 0.1 MPa to 0.50 MPa, and the addition time of the conjugated diene monomer and styrene monomer added at a constant rate within the range of 10 to 60 minutes, preferably within the range of 10 to 35 minutes or by adding them three or more times, the peak top value of the loss tangent (tanδ) can be controlled to be between 0.5 and 2.0, preferably between 0.5 and 1.5. Preferably, the reactor temperature is within the range of 56 to 84°C, the reactor pressure is within the range of 0.1 MPa to 0.40 MPa, and the addition time of the conjugated diene monomer and styrene monomer added at a constant rate is within the range of 10 to 60 minutes, preferably within the range of 10 to 35 minutes or by adding them three or more times. Another method involves controlling the peak top value when hydrogenating a block copolymer by setting the hydrogenation reaction temperature between 90°C and 120°C.

[0034] The block copolymer preferably consists of conjugated diene monomer units (a) derived from 1,2-bonds and / or 3,4-bonds and conjugated diene monomer units (b) derived from 1,4-bonds. Here, "conjugated diene monomer unit (a) derived from 1,2-bonds and / or 3,4-bonds" refers to a polymerization unit formed from a conjugated diene compound as a result of polymerization of the conjugated diene compound via 1,2-bonds and / or 3,4-bonds. Furthermore, "conjugated diene monomer unit (b) derived from 1,4-bonds" refers to a polymerization unit formed from conjugated diene compounds as a result of polymerization of conjugated diene compounds via 1,4-bonds.

[0035] The content of conjugated diene monomer units (a) derived from 1,2-bonds and / or 3,4-bonds (hereinafter also referred to as the vinyl bond content) relative to the total content of conjugated diene monomer units in the block copolymer is preferably 10 mol% to 50 mol%, more preferably 15 mol% to 50 mol%, even more preferably 15 mol% to 45 mol%, even more preferably 18 mol% to 40 mol%, even more preferably 20 mol% to 40 mol%, particularly preferably 21 mol% to 32 mol%, and most preferably 24 mol% to 30 mol%. The aforementioned vinyl bonding amount being 10 mol% or more tends to allow for a reduction in the amount of polymer added to asphalt. Because the vinyl bonding content is 50 mol% or less, the asphalt composition of this embodiment tends to have high heat aging resistance and weather resistance. The amount of vinyl bonding can be measured by NMR, and specifically, it can be determined by the method described in the examples below. Furthermore, the distribution of vinyl bonds in the copolymer block containing conjugated diene monomer units, i.e., polymer block (B), is not limited.

[0036] The content of conjugated diene monomer units (a) derived from unhydrogenated 1,2-bonds and / or 3,4-bonds, and conjugated diene monomer units (b) derived from 1,4-bonds, as well as the microstructure of the conjugated diene monomer units (ratio of cis, trans, and vinyl), can be adjusted by using polar compounds, etc., as described later.

[0037] In the block copolymer, the conjugated diene monomer unit consists of a conjugated diene monomer unit (a) derived from 1,2-bonds and / or 3,4-bonds and a conjugated diene monomer unit (b) derived from 1,4-bonds, and when the total content of the conjugated diene monomer unit is 100% by mass, it is preferable that the content of the hydrogenated alkenyl monomer unit (hereinafter also referred to as hydrogenated vinyl) (a1) derived from the conjugated diene monomer unit (a) is 10% by mass or more and 50% by mass or less. Preferably, the content of hydrogenated alkenyl monomer units (hereinafter also referred to as hydrogenated alkenyl monomer units) (b1) is 0% by mass or more and 90% by mass or less, and preferably, the sum of the content of structures in which the vinyl bond is not hydrogenated after hydrogenation (hereinafter also referred to as unhydrogenated vinyl) (a2) and structures in which the 1,4-bond is not hydrogenated (hereinafter also referred to as unhydrogenated alkenyl monomer units) (b2) is 0% by mass or more and 90% by mass or less. By using such a block copolymer, a good balance is achieved between the dispersion of resin and the dispersion of block copolymer in the asphalt, further improving the softening point and elongation of the asphalt composition of this embodiment.

[0038] From the viewpoint of balancing the softening point and elongation performance of the asphalt composition of this embodiment, the hydrogenated vinyl (a1) content is preferably 10% by mass or more and 45% by mass or less, more preferably 15% by mass or more and 40% by mass or less, and even more preferably 20% by mass or more and 30% by mass or less. When the resin to be added is polypropylene or a mixture with polypropylene, from the viewpoint of compatibility with asphalt, the content of hydrogenated vinyl (a1) is preferably 20% by mass or more, and more preferably 30% by mass or more. When the added resin is polyethylene, a mixed resin mainly composed of polyethylene, or an ethylene copolymer, from the viewpoint of compatibility with asphalt, the hydrogenated vinyl (a1) content is preferably 40% by mass or less, more preferably 30% by mass or less, and even more preferably 20% by mass or less.

[0039] Furthermore, from the viewpoint of balancing the softening point and elongation performance of the asphalt composition of this embodiment, the content of hydrogenated alkenyl monomer units (b1) is preferably 10% by mass or more and 70% by mass or less, more preferably 15% by mass or more and 65% by mass or less, and even more preferably 30% by mass or more and 65% by mass or less. Furthermore, from the viewpoint of resin compatibility, the content of hydrogenated alkenyl monomer units (b1) is preferably 15% by mass or more, more preferably 25% by mass or more, and even more preferably 35% by mass or more. A hydrogenated alkenyl monomer unit (b1) content of 35% by mass or more improves the compatibility between polyethylene, polyethylene-based mixed resins, and ethylene copolymers and asphalt, resulting in an asphalt composition with high elongation.

[0040] Furthermore, from the viewpoint of balancing the softening point and elongation performance of the asphalt composition of this embodiment, the sum of the content of unhydrogenated vinyl (a2) and unhydrogenated alkenyl monomer units (b2) is preferably 0% by mass or more and 90% by mass or less, more preferably 0% by mass or more and 80% by mass or less, even more preferably 5% by mass or more and 70% by mass or less, and even more preferably 10% by mass or more and 60% by mass or less.

[0041] The content of hydrogenated vinyl (a1), hydrogenated alkenyl monomer units (b1), unhydrogenated vinyl (a2), and unhydrogenated alkenyl monomer units (b2) can be determined by the method described in the examples below. In block copolymers, the content of hydrogenated vinyl (a1), hydrogenated alkenyl monomer units (b1), unhydrogenated vinyl (a2), unhydrogenated alkenyl monomer units (b2), and the microstructure of conjugated diene monomer units (ratio of cis, trans, and vinyl) can be controlled to a desired numerical range by using polar compounds, as described later, and by adjusting the temperature and hydrogen supply during the hydrogenation process.

[0042] From the viewpoint of high elongation, high elongation recovery, high elongation at low temperatures, compatibility with polar resins, and adhesion to aggregates of the asphalt composition of this embodiment, the block copolymer preferably has at least one functional group selected from the group consisting of hydroxyl groups, acid anhydride groups, epoxy groups, amino groups, amide groups, silanol groups, and alkoxysilyl groups. Among these, it is more preferable that the block copolymer has at least one functional group selected from the group consisting of amino groups, amide groups, silanol groups, and alkoxysilyl groups, and even more preferable that it has an amino group and an alkoxysilyl group. From the viewpoint of dispersing the asphaltene component in the asphalt composition, it is preferable that the block copolymer has amino groups and alkoxysilyl groups. The asphaltene component contained in asphalt is expected to increase as petroleum refining technology becomes more advanced. When the asphaltene component increases, the asphalt hardens, impairing its function as an adhesive and causing cracking in the asphalt composition. The adverse effects of the increased asphaltene component on the asphalt composition can be mitigated by adjusting the compatibility with asphalt through structural control of the block copolymer. For example, if the block copolymer has the above-mentioned amino groups and alkoxysilyl groups, it interacts with the polar groups of asphaltene, improving compatibility. It is more preferable that the block copolymer contains 2 moles or more of at least one functional group selected from the group consisting of amino groups and amide groups, per mole of its molecule. The above functional group can be introduced using a polar compound having the functional group by the method for producing the block copolymer described later.

[0043] In the road paving asphalt mixture containing the asphalt composition and aggregate of this embodiment, it is preferable that the block copolymer has alkoxysilyl groups from the viewpoint of adhesion between the asphalt composition and the aggregate. The presence of alkoxysilyl groups in the block copolymer leads to high adhesion through interaction with silanol groups on the aggregate surface, and tends to improve the aggregate peel resistance of the road paving asphalt mixture.

[0044] The melt flow rate (MFR) of the block copolymer is preferably 0.05 g / 10 min or more and 10 g / 10 min or less. Because the MFR of the block copolymer is within the above range, the asphalt composition of this embodiment has an excellent balance of processability and softening point. The MFR of the block copolymer is more preferably 0.05 g / 10 min to 8 g / 10 min, and even more preferably 0.05 g / 10 min to 6 g / 10 min. Furthermore, from the viewpoint of manufacturability, the MFR of the block copolymer is preferably 0.05 g / 10 min or more, more preferably 0.10 g / 10 min or more, and even more preferably 0.20 g / 10 min or more. Furthermore, from the viewpoint of the recovery after tensile strength and the resistance to aggregate taxidermy of the asphalt composition of this embodiment, the MFR of the block copolymer is preferably 5 g / 10 min or less, more preferably 2 g / 10 min or less, and even more preferably 1 g / 10 min or less. The MFR of block copolymers can be calculated using a melt indexer (L247; manufactured by TECHNOLSEVEN CO.,LTD) in accordance with JIS K7210. Preferably, the test temperature is 230°C, the test load is 2.16 kgf, and the measured value is measured under L conditions at g / 10 mins.

[0045] In the block copolymer, from the viewpoint of balancing the softening point and melt viscosity of the asphalt composition of this embodiment, the weight-average molecular weight (Mw) is preferably 50,000 to 400,000, more preferably 50,000 to 350,000, even more preferably 50,000 to 300,000, even more preferably 60,000 to 300,000, even more preferably 70,000 to 280,000, particularly preferably 70,000 to 260,000, and most preferably 70,000 to less than 200,000. From the viewpoint of the tensile recovery, aggregate peeling resistance, and balance between softening point and melt viscosity of the asphalt composition of this embodiment, the weight-average molecular weight (Mw) of the block copolymer is preferably 50,000 or more, more preferably 100,000 or more, even more preferably 130,000 or more, even more preferably 160,000 or more, and even more preferably 170,000 or more. Furthermore, from the viewpoint of manufacturability, melt viscosity of the asphalt composition of this embodiment, and dispersibility, the weight-average molecular weight (Mw) of the block copolymer is preferably 400,000 or less, more preferably 320,000 or less, even more preferably 300,000 or less, even more preferably 280,000 or less, even more preferably 260,000 or less, particularly preferably 250,000 or less, even more preferably 230,000 or less, and most preferably less than 200,000.

[0046] From the viewpoint of balancing the softening point and melt viscosity of the asphalt composition of this embodiment, the molecular weight distribution (Mw / Mn) of the block copolymer (ratio of weight-average molecular weight (Mw) to number-average molecular weight (Mn)) is preferably 2.0 or less, more preferably 1.8 or less, and even more preferably 1.5 or less. From the viewpoint of balancing the softening point and melt viscosity of the asphalt composition of this embodiment and reducing the amount of polymer added to the asphalt, the molecular weight distribution of the block copolymer is preferably 1.01 or higher, more preferably 1.03 or higher, even more preferably 1.05 or higher, even more preferably 1.10 or higher, even more preferably 1.11 or higher, and particularly preferably 1.20 or higher. Furthermore, from the viewpoint of improving manufacturability and reducing the amount of block copolymer added to asphalt, the molecular weight distribution of the block copolymer is preferably 10.0 or less, more preferably 5.0 or less, even more preferably 2.0 or less, even more preferably 1.7 or less, even more preferably 1.4 or less, and particularly preferably 1.3 or less.

[0047] The weight-average molecular weight and molecular weight distribution can be determined by the method described in the examples below. When the block copolymer is hydrogenated, the weight-average molecular weight and molecular weight distribution are substantially equal to those of the block copolymer before hydrogenation. Therefore, the weight-average molecular weight and molecular weight distribution when the block copolymer is hydrogenated may be determined by measuring the weight-average molecular weight and molecular weight distribution of the block copolymer before hydrogenation.

[0048] In this embodiment, from the viewpoints of productivity, softening point, viscosity, and dispersibility, it is preferable that the weight-average molecular weight of the block copolymer and the hydrogenation rate are within the range of the following relational expressions. Upper limit: Y = -0.114X + 38.83 Lower limit: Y = -0.1X + 23 (X represents the hydrogenation rate (mol%), and Y represents the weight-average molecular weight (ten thousand).)

[0049] Regarding the structure of the block copolymer, there is no particular limitation, and examples include those having a structure represented by the following formula. (A - B) n+1 , A - (B - A) n , B - (A - B) n+1 , [(A - B) n m -X, [(B - A) n -B] m , [(A - B) n -A] m , [(B - A) n+1 m -X (In the above formula, each A independently represents a polymer block (A) mainly composed of vinyl aromatic monomer units. Each B independently represents a polymer block (B) containing conjugated diene monomer units and vinyl aromatic monomer units. Each n is independently 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 independently represents a residue of a coupling agent or a residue of a polyfunctional initiator.) The block copolymer may be any mixture of those having the structure represented by the above formula.

[0050] ​ Among the various formulas representing block copolymers, polymers with an ABA structure are preferred from the viewpoint of balancing asphalt binder performance. Furthermore, regarding the coupling structure, a linear structure is preferred from the viewpoint of the low viscosity of the asphalt composition of this embodiment, and a radial structure is preferred from the viewpoint of the high softening point of the asphalt composition of this embodiment. Moreover, as for the radial structure, a 3-branched or 4-branched structure is preferred, and a structure having both a 3-branched and a 4-branched structure is more preferred. Furthermore, the ratio of 3-branched to 4-branched structures is preferably 5 / 95 to 95 / 5 for 3-branched / 4-branched structures, more preferably 90 / 10 or less for 3-branched / 4-branched structures from the viewpoint of a high softening point, even more preferably 75 / 25 or less, even more preferably 60 / 40 or less, and even more preferably 40 / 60 or less. Furthermore, from the viewpoint of low viscosity, it is preferable that the ratio of 3-branched to 4-branched is 10 / 90 or higher, more preferably 25 / 75 or higher, even more preferably 50 / 50 or higher, and even more preferably 70 / 30 or higher.

[0051] In block copolymers, vinyl aromatic monomer units in polymer block (B) may be uniformly distributed, or they may be distributed in a tapered, stepped, convex, or concave manner. Here, a tapered structure refers to a structure in which the content of vinyl aromatic monomer units gradually increases along the polymer chains in polymer block (B). If S1 is the content of vinyl aromatic monomer units in polymer block (B) immediately after the start of polymerization, S2 is the content of vinyl aromatic monomer units in the polymer during polymerization, for example when half of the introduced monomers have polymerized, and S3 is the content of vinyl aromatic monomer units in polymer block (B) after polymerization is complete, then the structure satisfies the relationships S2 / S1>1 and S3 / S2>1. Polymer block (B) may contain multiple portions in which vinyl aromatic monomer units are uniformly distributed and / or in which they are distributed in a tapered manner. Polymer block (B) may also contain multiple segments with different vinyl aromatic monomer unit content.

[0052] The content of the short-chain vinyl aromatic monomer polymerization portion in polymer block (B) is preferably 50% by mass or more, when the total content of vinyl aromatic monomer units in polymer block (B) is taken as 100% by mass. By having the content of short-chain vinyl aromatic monomer polymerization moieties in polymer block (B) within the above range, an asphalt composition with excellent elongation and dispersibility can be obtained. Furthermore, the recovery after tensile stress, heat aging resistance, and aggregate peeling resistance of the asphalt composition of this embodiment are improved. From the viewpoint of elongation and dispersibility of the asphalt composition of this embodiment, the content of the short-chain vinyl aromatic monomer polymerization portion is more preferably 70% by mass or more, even more preferably 80% by mass or more, and even more preferably 90% by mass or more. There is no particular upper limit to the content of the short-chain vinyl aromatic monomer polymerization portion in polymer block (B), but it is preferably 100% by mass or less, and more preferably 99% by mass or less. Here, the short-chain vinyl aromatic monomer polymerization moiety is a component consisting of 2 to 6 vinyl aromatic monomer units in polymer block (B). Furthermore, the content of the short-chain vinyl aromatic monomer polymerization portion is determined by taking the total content of vinyl aromatic monomer units in polymer block (B) as 100% by mass, and then calculating the content of vinyl aromatic monomer units linked together in groups of 2 to 6.

[0053] Furthermore, the content of two linked vinyl aromatic monomer units per 100% by mass of vinyl aromatic monomer units in polymer block (B) is preferably 10% by mass or more and 45% by mass or less, more preferably 13% by mass or more and 42% by mass or less, and even more preferably 19% by mass or more and 36% by mass or less, from the viewpoint of high compatibility between the block copolymer and asphalt.

[0054] Furthermore, from the viewpoint of high compatibility between the block copolymer and asphalt, the content of three linked vinyl aromatic monomer units per 100% by mass of vinyl aromatic monomer units in polymer block (B) is preferably 45% by mass or more and 80% by mass or less, more preferably 45% by mass or more and 75% by mass or less, and even more preferably 45% by mass or more and 65% by mass or less.

[0055] The content of the short-chain vinyl aromatic monomer polymerization portion in polymer block (B) can be controlled, for example, by adjusting the number of times the conjugated diene monomer and aromatic vinyl monomer are added, the addition time, and the temperature inside the reactor when polymerizing polymer block (B). It can be controlled by adjusting either the number of additions, the addition time, or the reactor temperature, or by adjusting them in an appropriate combination.

[0056] The number of times the conjugated diene monomer and aromatic vinyl monomer are added tends to increase the content of the short-chain vinyl aromatic monomer polymerization portion as the number of additions increases, so it is preferable to add them two or more times. Increasing the addition time tends to increase the content of short-chain vinyl aromatic monomer polymerization, so it is preferable to keep the addition time between 20 minutes and 80 minutes. When polymerizing block copolymers, increasing the reactor temperature tends to increase the content of short-chain vinyl aromatic monomer polymerization, and a temperature of 56°C to 90°C is preferable.

[0057] The bulk density of the block copolymer before mixing with asphalt is preferably 0.05 g / mL or higher, from the viewpoint of high solubility in asphalt. The bulk density of the block copolymer is more preferably 0.10 g / mL or higher, even more preferably 0.17 g / mL or higher, and even more preferably 0.25 g / mL or higher. Furthermore, from the viewpoint of high solubility in asphalt, the bulk density of the block copolymer is preferably 0.45 g / mL or less, more preferably 0.38 g / mL or less, even more preferably 0.35 g / mL or less, and even more preferably 0.30 g / mL or less.

[0058] The specific surface area of ​​the block copolymer before mixing with asphalt is 0.10 m², from the viewpoint of high solubility in asphalt. 2 Preferably 0.20m / g or more, 2 More preferably 0.30m / g or more, 2 More preferably 0.41m / g or more. 2 A value of / g or higher is even more preferable.

[0059] (Method of manufacturing block copolymers) Block copolymers can be produced, for example, by anionic living polymerization of monomers using polymerization initiators such as organoalkali metal compounds in a hydrocarbon solvent.

[0060] Examples of hydrocarbon solvents include, but are not limited to, aliphatic hydrocarbons such as n-butane, isobutane, n-pentane, n-hexane, n-heptane, and n-octane; alicyclic hydrocarbons such as cyclohexane, cycloheptane, and methylcycloheptane; and aromatic hydrocarbons such as benzene, toluene, xylene, and ethylbenzene.

[0061] Polymerization initiators are not limited to the following, but examples include aliphatic hydrocarbon alkali metal compounds, aromatic hydrocarbon alkali metal compounds, and organic amino alkali metal compounds that have anionic polymerization activity toward conjugated dienes and vinyl aromatic compounds. Examples of alkali metals include, but are not limited to, lithium, sodium, and potassium.

[0062] When polymerizing a conjugated diene compound and a vinyl aromatic compound using an organoalkali metal compound as a polymerization initiator, a polar compound such as a tertiary amine compound or ether compound may be added to adjust the amount of vinyl bonds (1,2-bonds or 3,4-bonds) resulting from the conjugated diene monomer units incorporated into the block copolymer, or to adjust the random polymerization properties of the conjugated diene compound and the vinyl aromatic compound.

[0063] Examples of tertiary amine compounds as polar compounds include, but are not limited to, compounds represented by the formula R1R2R3N (wherein R1, R2, and R3 are each independently hydrocarbon groups having 1 to 20 carbon atoms or hydrocarbon groups having a tertiary amino group). Specifically, examples include trimethylamine, triethylamine, tributylamine, N,N-dimethylaniline, N-ethylpiperidine, N-methylpyrrolidine, N,N,N',N'-tetramethylethylenediamine, N,N,N',N'-tetraethylethylenediamine, 1,2-dipiperidinoethane, trimethylaminoethylpiperazine, N,N,N',N”,N”-pentamethylethylenetriamine, and N,N'-dioctyl-p-phenylenediamine.

[0064] Examples of ether compounds as polar compounds include, but are not limited to, linear ether compounds and cyclic ether compounds. Examples of linear ether compounds include, but are not limited to, dimethyl ether, diethyl ether, and diphenyl ether; dialkyl ether compounds of ethylene glycol, such as ethylene glycol dimethyl ether, ethylene glycol diethyl ether, and ethylene glycol dibutyl ether; and dialkyl ether compounds of diethylene glycol, such as diethylene glycol dimethyl ether, diethylene glycol diethyl ether, and diethylene glycol dibutyl ether. Examples of cyclic ether compounds include, but are not limited to, tetrahydrofuran, dioxane, 2,5-dimethyloxolane, 2,2,5,5-tetramethyloxolane, 2,2-bis(2-oxolanyl)propane, and alkyl ethers of furfuryl alcohol.

[0065] In this embodiment, the method for polymerizing the conjugated diene compound and the vinyl aromatic compound using an organoalkali metal compound as a polymerization initiator may be batch polymerization, continuous polymerization, or a combination thereof. The polymerization temperature is usually between 0°C and 180°C, and preferably between 30°C and 150°C. The time required for polymerization varies depending on other conditions, but is usually within 48 hours, preferably 0.1 to 10 hours. The polymerization system atmosphere is preferably an inert gas atmosphere such as nitrogen gas. The polymerization pressure is not particularly limited, as long as it is within a range sufficient to maintain the monomer and solvent in the liquid phase within the polymerization temperature range described above. Care must be taken to prevent the polymerization system from being contaminated with impurities (such as water, oxygen, or carbon dioxide) that would deactivate the catalyst and living polymer.

[0066] In the manufacturing process of block copolymers, a coupling reaction can also be carried out using a coupling agent with two or more functionalities once the polymerization described above is complete. There are no particular limitations on coupling agents with two or more functionalities; known ones can be used. Examples of bifunctional coupling agents include, but are not limited to, dihalogen compounds such as dimethyldichlorosilane and dimethyldibromosilane; and acid esters such as methyl benzoate, ethyl benzoate, phenyl benzoate, and phthalates. Polyfunctional coupling agents with three or more functions are not limited to the following, but include, for example, polyalcohols with three or more functions; polyvalent epoxy compounds such as epoxidized soybean oil and diglycidyl bisphenol A; and formula R 4-n SiX n Silicon halide compounds represented by formula R (wherein each R independently represents a hydrocarbon group having 1 to 20 carbon atoms, each X independently represents a halogen atom, and n represents 3 or 4), such as methylsilyl trichloride, t-butylsilyl trichloride, silicon tetrachloride, and their brominateds; formula R 4-n Sn nExamples of polyvalent halogen compounds represented by tin halides (where each R independently represents a hydrocarbon group having 1 to 20 carbon atoms, each X independently represents a halogen atom, and n represents 3 or 4) include methyltin trichloride, t-butyltin trichloride, and tin tetrachloride. Dimethyl carbonate, diethyl carbonate, and 1,3-bis(N,N'-diglycidylaminomethyl)cyclohexane can also be used as polyfunctional coupling agents.

[0067] The block copolymer may be a hydrogenated product. There are no particular limitations on the hydrogenation method; known methods can be used. While not particularly limited, conventional hydrogenation catalysts used when hydrogenating block copolymers include (1) supported heterogeneous hydrogenation catalysts in which metals such as Ni, Pt, Pd, and Ru are supported on carbon, silica, alumina, diatomaceous earth, etc.; (2) so-called Ziegler-type hydrogenation catalysts using organic acid salts of Ni, Co, Fe, Cr, etc. or transition metal salts such as acetylacetone salts and reducing agents such as organoaluminum; and (3) homogeneous hydrogenation catalysts such as so-called organometallic complexes such as organometallic compounds of Ti, Ru, Rh, and Zr. As a hydrogenation catalyst, although not limited to the following, hydrogenation catalysts described in Japanese Patent Publication No. 63-4841, Japanese Patent Publication No. 1-53851, and Japanese Patent Publication No. 2-9041 can be used. Preferred hydrogenation catalysts include mixtures with titanocene compounds and / or reducing organometallic compounds. The titanocene compounds are not limited to those listed below, but for example, compounds described in Japanese Patent Publication No. 8-109219 can be used. Specifically, examples include compounds having at least one ligand with a (substituted) cyclopentadienyl skeleton, an indenyl skeleton, or a fluorenyl skeleton, such as biscyclopentadienyl titanium dichloride and monopentamethylcyclopentadienyl titanium trichloride. Reducing organometallic compounds include, but are not limited to, organolithium and other organoalkali metal compounds, organomagnesium compounds, organoaluminum compounds, organoboron compounds, or organozinc compounds.

[0068] The hydrogenation reaction of block copolymers is usually carried out in a temperature range of 0 to 200°C, preferably in a temperature range of 30 to 150°C. The pressure of the hydrogen used in the hydrogenation reaction is typically between 0.1 MPa and 15 MPa, preferably between 0.2 MPa and 10 MPa, and more preferably between 0.3 MPa and 5 MPa. The hydrogenation reaction time is usually 3 minutes to 10 hours, preferably 10 minutes to 5 hours. Hydrogenation reactions can be carried out using batch processes, continuous processes, or a combination of both.

[0069] The solution of the hydrogenated block copolymer obtained as described above can be separated from the solution by removing catalyst residue as needed. Methods for separating the solvent include, for example, adding a polar solvent that is a poor solvent for the hydrogenated block copolymer, such as acetone or alcohol, to the reaction solution after hydrogenation to precipitate and recover the hydrogenated block copolymer; immersing the reaction solution in hot water under stirring and removing the solvent by steam stripping; and directly heating the polymer solution to remove the solvent by distillation.

[0070] Various stabilizers, such as phenolic stabilizers, phosphorus-based stabilizers, sulfur-based stabilizers, and amine-based stabilizers, can be added to the block copolymer.

[0071] In the hydrogenation process of the block copolymer, the conjugated bonds of the vinyl aromatic monomer units may be hydrogenated. The hydrogenation rate of conjugated bonds in the total vinyl aromatic monomer units is preferably 30 mol% or less, more preferably 10 mol% or less, and even more preferably 3 mol% or less. Furthermore, the lower limit of the hydrogenation rate of conjugated bonds in the total vinyl aromatic monomer is not particularly limited, but is 0 mol%. Having the hydrogenation rate of conjugated bonds in the total vinyl aromatic monomer within the above range tends to result in higher dispersibility of the asphalt composition of this embodiment.

[0072] (Modification of block copolymers) Furthermore, if it is necessary to improve the softening point of the asphalt composition of this embodiment, the adhesion resistance of the asphalt composition to aggregate, the high resistance to flow rutting and high abrasion of the asphalt mixture containing aggregate, it is preferable to impart functional groups to the block copolymer. One modification method for imparting functional groups to block polymers is to add a modifying agent that generates a functional group-containing atomic group to the living end of the block copolymer. The elements contained in the functional group are particularly preferably oxygen, nitrogen, phosphorus, sulfur, tin, and silicon.

[0073] The functional group is preferably at least one selected from hydroxyl groups, acid anhydride groups, epoxy groups, amino groups, silanol groups, and alkoxysilyl groups. Furthermore, if the denaturation reaction imparts a branched structure, it also functions as a coupling agent.

[0074] Furthermore, from the viewpoint of further improving resistance to flow rutting, it is preferable that the block copolymer has a functional group containing nitrogen. It is more preferable that the functional group is contained in 2 to 4 mol% per molecule. It is even more preferable that it contains both a functional group containing a nitrogen atom and a functional group containing an oxygen atom. By having nitrogen atoms and oxygen atoms in the functional group, the compatibility with asphalt tends to be further improved through interaction with the polar components in asphalt (asphaltene components, resin components) mentioned above.

[0075] The aforementioned denaturing agents are not limited to the following, but include, for example, tetraglycidylmetoxylendiamine, tetraglycidyl-1,3-bisaminomethylcyclohexane, tetraglycidyl-p-phenylenediamine, tetraglycidyldiaminodiphenylmethane, diglycidylaniline, γ-caprolactone, γ-glycidoxyethyltrimethoxysilane, γ-glycidoxypropyltrimethoxysilane, γ-glycidoxypropyltriphenoxysilane, γ-glycidoxypropylmethyldimethoxysilane, γ-glycidoxypropyldiethylethoxysilane, γ-glycidoxypropyldimethylethoxysilane, γ-glycidoxypropylmethyldiisopropeneoxysilane, bis(γ-glycidoxypropyl)dimethoxysilane, bis(γ-glycidoxypropyl)diethoxysilane, β Examples include -(3,4-epoxycyclohexyl)ethyl-tripropoxysilane, β-(3,4-epoxycyclohexyl)ethyl-tributoxysilane, β-(3,4-epoxycyclohexyl)ethyl-methyldipropoxysilane, β-(3,4-epoxycyclohexyl)ethyl-methyldibutoxysilane, β-(3,4-epoxycyclohexyl)ethyl-methyldiphenoxysilane, β-(3,4-epoxycyclohexyl)ethyl-dimethylmethoxysilane, β-(3,4-epoxycyclohexyl)ethyl-diethylethoxysilane, β-(3,4-epoxycyclohexyl)ethyl-dimethylethoxysilane, 1,3-dimethyl-2-imidazolidinone, 1,3-diethyl-2-imidazolidinone, N,N'-dimethylpropyleneurea, and N-methylpyrrolidone.

[0076] The amount of the above-mentioned modifying agent used is preferably 0.5 to 5 equivalents per equivalent of the living end of the block copolymer.

[0077] Furthermore, radial-type block copolymers containing functional groups are more preferable from the standpoint of balancing low viscosity and high softening point.

[0078] Crosslinking is preferable when it is necessary to improve the high solubility of block copolymers and other polymers in asphalt, the adhesion resistance of asphalt compositions to aggregates, and the high resistance of aggregate-containing asphalt mixtures to rutting and abrasion. Examples of crosslinking agents include sulfur / sulfur compound-based, phosphorus-based, organic peroxide-based, epoxy-based, isocyanate-based, resin-based, amine-based, metal chelate-based, and thiuram. You may use only one of these types on its own, or you may use two or more types in combination.

[0079] Sulfur and sulfur compound-based crosslinking agents can be used, but are not limited to the following: elemental sulfur, sulfur chloride, morpholine disulfide, tetramethylthiuram disulfide, selenium dimethyldithiocarbamate, 2-(4'-morpholinodithio)benzothiazole, 4,4'-dithiodimorpholine, thioacetamide, etc. Phosphorus-based crosslinking agents can be used, but are not limited to the following: anhydrous phosphoric acid (P2O5), polyphosphate, oxyphosphorus trichloride (POCl3), phosphorus trichloride (PCl3), or phosphorus pentasulfide (P2S5). Organic peroxide-based crosslinking agents can be used, but are not limited to the following: tertiary butyl hydroperoxide, 1,1,3,3-tetramethylbutyl hydroperoxide, cumene hydroperoxide, diisopropylbenzene hydroperoxide, 2,5-dimethyl-2,5-di(tertiary butylperoxy)hexane, 2,5-dimethyl-2,5-di(tertiary butylperoxy)hexine-3, 1,3-bis(tertiary butylperoxyisopropyl)benzene, 2,5-dimethyl-2,5-di(benzoylperoxy)hexane, 1,1-bis(tertiary butylperoxy)-3,3,5-trimethylcyclohexane, n-butyl-4,4-bis(tertiary butylperoxy)valerate, benzoyl peroxide, tertiary butylperoxyisobutyrate, etc. Examples of epoxy crosslinking agents that can be used include, but are not limited to, ethylene n-butyl acrylate glycidyl methacrylate (glycidyl methacrylate), neopentyl glycol diglycidyl ether, hexanediol diglycidyl ether, trimethylolpropane polyglycidyl ether, and hexahydrophthalate diglycidyl ester. The isocyanate-based crosslinking agents can be, but are not limited to, triallyl isocyanurate, trimethylene diisocyanate, tetramethylene diisocyanate, pentamethylene diisocyanate, hexamethylene diisocyanate, and the like. Examples of resin-based crosslinking agents include, but are not limited to, alkylphenol-formaldehyde resins and hexamethoxymethyl-melamine resins. Examples of amine-based compounds that can be used include hexamethylenediamine, triethylenetetramine, tetraethylenepentamine, hexamethylenediamine carbamate, N,N-disinnamyridene-1,6-hexanediamine, 4,4-methylenebis(cyclohexylamine)carbamate, and 4,4-methylenebis(2-chloroaniline). Examples of metal chelating crosslinking agents that can be used include, but are not limited to, zinc methacrylate, magnesium methacrylate, zinc dimethacrylate, and magnesium dimethacrylate. Among these, sulfur / sulfur-based compounds and polyphosphates are preferred due to their significant effects and economic advantages.

[0080] The amount of crosslinking agent in the asphalt composition of this embodiment is preferably 0.03% by mass or more, more preferably 0.05% by mass or more, and even more preferably 0.10% by mass or more, from the viewpoint of suppressing the generation of toxic gases during manufacturing and economic efficiency. Furthermore, from the viewpoint of high adhesion resistance to aggregate, high resistance to rutting, and high abrasion resistance of the asphalt composition, a combination of a radial polymer using 1,3-bis(N,N'-diglycidylaminomethyl)cyclohexane as a coupling agent and a sulfur / sulfur-based compound or polyphosphate is preferred.

[0081] The asphalt composition of this embodiment contains 85 to 99 parts by mass of asphalt and 0.1 to 15 parts by mass of the block copolymer described above, and further contains 0.1 to less than 15 parts by mass of the resin and / or rubber, with the total content of the block copolymer and the resin and / or rubber being 0.1 to 15 parts by mass.

[0082] (asphalt) The asphalt composition of this embodiment contains asphalt. Asphalt can include, but is not limited to, the following: by-products of petroleum refining (petroleum asphalt), natural products (natural asphalt), and mixtures of these with petroleum products. The main component of asphalt is a substance called bitumen. Examples of asphalt include, but are not limited to, straight asphalt, semi-blown asphalt, blown asphalt, tar, pitch, cutback asphalt with added oil, and asphalt emulsion. These may be used individually or in combination of two or more. Suitable asphalts include straight asphalts having a penetration (measured according to JIS-K2207) of preferably 30 (1 / 10 mm) or more and 300 (1 / 10 mm) or less, more preferably 40 (1 / 10 mm) or more and 200 (1 / 10 mm) or less, and even more preferably 45 (1 / 10 mm) or more and 150 (1 / 10 mm) or less.

[0083] From the viewpoint of extending the lifespan of roads, it is preferable that the asphalt contains 15% to 25% by mass of asphaltene, 15% to 30% by mass of resin, and 35% to 60% by mass of aromatic compounds. When the asphaltene content is 15% by mass or more, the heat resistance of the asphalt composition of this embodiment tends to improve, and when the asphaltene content is 25% by mass or less, the processability (low melt viscosity) and elongation tend to improve further. When the resin content is 15% by mass or more, the heat resistance and processability (low melt viscosity) of the asphalt composition of this embodiment tend to be further improved, and when the resin content is 30% by mass or less, the elongation tends to be further improved. A block copolymer with an aromatic content of 35% by mass or more improves compatibility and provides greater storage stability. Furthermore, an aromatic content of 60% by mass or less tends to result in greater flexibility and improved elongation.

[0084] (Amount of block copolymer added) In the asphalt composition of this embodiment, the content of the block copolymer is 0.1 parts by mass to 15 parts by mass, preferably 1 part by mass to 15 parts by mass, and more preferably 3 parts by mass to 15 parts by mass, when the asphalt content is 85 parts by mass to 99 parts by mass. To ensure the required physical properties of the asphalt composition in this embodiment, the preferred content of block copolymer is influenced by the type and amount of resin and rubber added. Generally, by setting the block copolymer content to 0.1 parts by mass or more, a good softening point and rubber elasticity can be obtained, and the compatibility between the resin and asphalt, as described later, is improved. Furthermore, by setting the block copolymer content to 15 parts by mass or less, a good balance between mechanical properties and viscosity (processability) can be achieved.

[0085] The asphalt composition of this embodiment contains resins and / or rubbers other than block copolymers. However, when a resin is included and the degree of crystallinity of the added resin exceeds 60%, the preferred amount of block copolymer to be added is preferably 1 to 15 parts by mass, more preferably 3 to 15 parts by mass, and even more preferably 5 to 15 parts by mass, when the asphalt is 85 to 99 parts by mass. Adding 1 part by mass or more of block copolymer inhibits the crystallization of the resin in the asphalt composition, resulting in finer particle size distribution of the resin in the asphalt composition and a tendency to improve storage stability. Furthermore, adding 15 parts by mass or less of block copolymer tends to improve the processability (low melt viscosity) of the asphalt composition. When the degree of crystallinity of the added resin is 60% or less, the preferred amount of block copolymer to add is preferably 1 to 15 parts by mass, when the asphalt is 85 to 99 parts by mass. This allows for a relative increase in the amount of resin with a lower degree of crystallinity compared to the resin with a higher degree of crystallinity mentioned above. Adding a highly crystallinity resin results in large resin particles in the asphalt composition, which reduces storage stability. Therefore, it is necessary to increase the amount of block copolymer, which is a compatibilizer. However, by selecting a resin with low crystallinity, the crystallization of the resin in the asphalt composition is reduced, and storage stability can be ensured even with a small amount of block copolymer (compatibilizer). In other words, from the viewpoint of the physical properties of the asphalt composition, it is often not necessary to increase the amount of resin added to more than 5 parts by mass in terms of softening point and rutting resistance. However, from the viewpoint of sustainable development, it is conceivable that it may be desirable to use resins that are unsuitable for material recycling as part of the asphalt composition. In this case, from the viewpoint of ensuring the flexibility of the asphalt composition while increasing the amount of resin added, it is preferable to select a resin with a low degree of crystallinity. In terms of specific forms, for resins with a crystallinity of 90% or more, there is high-density polyethylene (HDPE), and when this high-density polyethylene (HDPE) is added to asphalt, it is preferable that the amount of block copolymer added is three times or more the amount of high-density polyethylene (HDPE). On the other hand, for resins with a crystallinity of 60% or less, there are low-density polyethylene (LDPE) and ethylene vinyl acetate copolymer (EVA), and when these resins with a crystallinity of 60% or less are added to asphalt, the amount of block copolymer added can be 0.5 times or less the amount of the resin added.

[0086] (resin) The asphalt composition of this embodiment contains resin and / or rubber. The aforementioned resin is a resin other than the block copolymer described above. If a resin is included, the resin content is 0.1 parts by mass or more and less than 15 parts by mass, preferably 0.1 parts by mass or more and less than 10 parts by mass, when the asphalt content is 85 parts by mass or more and 99 parts by mass or less. If rubber is included, the rubber content is 0.1 parts by mass or more and less than 15 parts by mass, preferably 0.1 parts by mass or more and less than 10 parts by mass, when the asphalt content is 85 parts by mass or more and 99 parts by mass or less. By including 0.1 parts by mass or more of resin and / or rubber, a high softening point, processability (low viscosity), and rutting resistance can be obtained, while keeping it below 15 parts by mass provides a good balance between compatibility and mechanical properties. Furthermore, from the viewpoint of economic efficiency and recyclability, the amount of resin added is preferably 1 part by mass or more, more preferably 5 parts by mass or more, and more preferably 10 parts by mass or more.

[0087] In the asphalt composition of this embodiment, the resin to be blended is an amorphous resin with a glass transition temperature of 170°C or lower, or a crystalline resin with a melting point of 170°C or lower, from the viewpoint of shortening the dissolution time during the manufacture of the asphalt composition. These may be used individually or as a mixture of two or more types. Since the temperature conditions when manufacturing the asphalt composition are usually around 180°C, a resin having a glass transition temperature or melting point below that temperature is preferred. From the perspective of combining with block copolymers and asphalt, it is understood that the influence of whether the resin is crystalline or amorphous is minimal as long as the respective structures are appropriately set. However, since the manufacturing temperature of modified asphalt is generally around 180°C, an amorphous resin is preferable because it melts more easily. Examples of resins used in the asphalt composition of this embodiment that have a glass transition temperature of 170°C or less when the resin is amorphous, or a melting point of 170°C or less when the resin is crystalline, are listed below. Amorphous resins having a glass transition temperature of 170°C or lower include vinyl chloride resin, vinyl acetate resin, polyvinyl alcohol, polyvinyl butyral, polystyrene, ABS resin, polymethyl methacrylate, polyurethane, ionomer resin, polyphenylene ether, and derivatives thereof. Examples of crystalline resins having a melting point of 170°C or lower include cellulose, polyethylene, ethylene-α-olefin copolymers (EPM, EBR, EOR, EPDM, etc.), ethylene-vinyl acetate copolymers, polypropylene (atactic structure, etc.), nylon resin, polyethylene terephthalate, and their derivatives.

[0088] If the degree of crystallinity of these added resins exceeds 60%, the amount of resin added is preferably 10% by mass or less, more preferably 5% by mass or less, and even more preferably 3% by mass or less, based on 100% by mass of the asphalt composition.

[0089] Among these resins, polyethylene having ethylene monomer units, ethylene-vinyl acetate copolymer (hereinafter also referred to as EVA), and ethylene-α-olefin copolymer are preferred in terms of high storage stability. From the viewpoint of manufacturing stability, the melting point is preferably 100°C or lower, more preferably 90°C or lower, and even more preferably 85°C or lower. Furthermore, from the viewpoint of dispersibility in asphalt, low-density polyethylene and ethylene-vinyl acetate copolymer are preferred, and ethylene-vinyl acetate copolymer is more preferred.

[0090] As for the resin used in the asphalt composition of this embodiment, from the viewpoint of using recycled resin as described later, a resin containing polyolefin and a polar resin is mentioned.

[0091] In view of the use of recycled resin in the asphalt composition of this embodiment, when the resin contains polyolefin and polar resin, it is preferable that the resin contains 70% by mass or more of polyolefin and 30% by mass or less of polar resin, from the viewpoint of maintaining good properties.

[0092] The resin used in the asphalt composition of this embodiment may be recycled resin. Recycled resin refers to resin obtained by recycling plastic bottles, films, sheets, foams, cross-linked foams, copolymers, etc., that contain one or more of the aforementioned resins. The recycled resin preferably has a purity of 50% or higher, more preferably 60% or higher, and even more preferably 70% or higher. A purity of 70% or higher in the recycled resin results in more uniform dispersion of resin particles in the asphalt composition, stabilizing its mechanical properties. However, even with recycled resin, if the purity is high (for example, 95% or higher), it is preferable from the standpoint of sustainable development goals to recycle it materially and / or chemically and use it for its original purpose. Even if the degree of sorting of the recovered resin is increased, a certain amount of recycled resin mixed with other materials or resins will inevitably be generated. Even if the purity of the recycled resin is around 70%, it can still be used in the asphalt composition of this embodiment, making it a useful application for low-purity recycled resin.

[0093] The composition of the recycled resin is not particularly limited, but examples include a resin mainly composed of polyethylene, with a total amount of high-density polyethylene, low-density polyethylene, and linear low-density polyethylene of 70% by mass or more, and containing other polar resins and impurities. Generally available recycled polyethylene contains 50% by mass of high-density polyethylene, 20% by mass of low-density polyethylene and linear low-density polyethylene, 20% by mass of polypropylene, and 10% by mass of other polar resins such as polyamide and polyethylene terephthalate. The mass ratios of these materials are not always constant, but fluctuate within a range of 1 to 10% by mass. From the viewpoint of ensuring performance, it is preferable to anticipate such fluctuations and determine the structure of the block copolymer so that it is compatible with asphalt within that range.

[0094] For example, when the high-density polyethylene content in the resin exceeds 50% by mass, it is preferable to set the hydrogenation rate of the block copolymer to 80% or more, preferably 90% or more, and even more preferably 100%, from the viewpoint of suppressing crystallization of high-density polyethylene in the asphalt composition and ensuring storage stability. Furthermore, by setting the vinyl bond content of the block copolymer to 50% by mass or less, the dispersed particle size of high-density polyethylene in the asphalt composition can be made finer. Because low-density polyethylene and linear low-density polyethylene have a lower degree of crystallinity than high-density polyethylene, even if their content exceeds 20% by mass, sufficient storage stability can be ensured with a hydrogenation rate of 60% or less for the block copolymer. When the polypropylene content exceeds 20% by mass, from the viewpoint of suppressing the crystallization of polypropylene in the asphalt composition of this embodiment and ensuring storage stability, it is preferable to set the hydrogenation rate of the block copolymer to 80% or more, more preferably to 90% or more, and even more preferably to 100%. Furthermore, by setting the vinyl bond content of the block copolymer to 50% by mass or more, the dispersed particle size of polypropylene in the asphalt composition can be made finer. However, if the vinyl bond content of the block copolymer is increased too much, the thermal degradation of the block copolymer progresses, and the mechanical properties of the asphalt composition tend to decrease.

[0095] If the content of polar resin exceeds 10% by mass, it is preferable that the block copolymer is modified with a predetermined polar compound having a functional group. From the viewpoint of ensuring the storage stability of the asphalt composition of this embodiment, it is preferable that the functional group interacts with both the polar resin and the asphalt. As a modifier, it is preferable to use, for example, a polar compound having a nitrogen atom and an oxygen atom, or a polar compound having a silicon atom and a nitrogen atom.

[0096] Furthermore, when the resin contains a large amount of impurities such as paper, it is preferable that the block copolymer be acid-modified by grafting maleic anhydride or the like, which has esterification reaction groups. Cellulose, the main component of paper, does not exhibit thermoplasticity like general-purpose resins, but because it has hydroxyl groups in its molecule, it can be compounded by an esterification reaction with maleic anhydride groups. In this way, impurities that can become crack initiation points in the asphalt composition are made finer, and the durability of the asphalt composition can be improved.

[0097] Furthermore, the asphalt composition of this embodiment can utilize crushed film or sheet as the resin. The aforementioned film may be a single-layer film or a laminated film. Examples include a single-layer polyolefin film and a multilayer film having a layer made of ethylene vinyl acetate copolymer and a layer made of polyethylene. Furthermore, the asphalt composition of this embodiment has advantages as a method of utilizing recycled resin in that it does not require the sorting process described above for films and sheets. Agricultural covering materials (various greenhouses, tunnels, mulch sheets, etc.) are prone to dirt accumulation and degradation due to ultraviolet rays, making them difficult to recycle. However, by crushing them and using them as materials for asphalt compositions, it becomes possible to effectively utilize them as resources.

[0098] The source of the recycled resin mentioned above is not particularly limited, but it is preferable that it be managed using blockchain technology. Blockchain technology is an "irreversible" database technology that can continuously record all history. Because this blockchain is accessible to all parties involved and the data cannot be tampered with, all parties involved can track "when, where, and through what flow" raw materials and products are distributed, thus achieving traceability. By using blockchain technology to visualize the recycling chain of recycled plastics, transparency in the history of recycled plastics can be ensured, creating an environment where recycled plastics can be used with confidence. It is also believed that this could encourage changes in consumer behavior. For example, by building a blockchain platform on the cloud and awarding points to consumers for their recycling actions on the system, and recording their environmental contribution experiences, it is possible to encourage changes in consumer behavior.

[0099] When recycled polyethylene is added to the asphalt composition of this embodiment, it is preferable that it be managed by a blockchain as described above. Specifically, it is preferable that it be managed by a blockchain composed of companies that collect discarded plastic products, companies that sort the collected plastic and process it into pellets, etc., and companies that mold and process the processed plastic pellets, etc., into products. As described above, the widespread use of roads constructed using modified asphalt compositions made from managed recycled plastics can accelerate the realization of a resource-recycling society.

[0100] The shape of the resin used in the asphalt composition of this embodiment is not particularly limited, but examples include pellets, crumbs, powder, crushed single-layer or multi-layer films and sheets, crushed casings, and crushed bottles. The crushed material may be a mixture of multiple resins, and the mixing ratio is not limited. The shape of the crushed film is not particularly limited, but from the viewpoint of dissolution rate in asphalt, it is preferably crushed into 5 mm x 5 mm chips, more preferably 3 mm x 3 mm, and even more preferably 1 mm x 1 mm or less. The thickness of the film crushed material is preferably 250 μm or less, more preferably 200 μm or less, and even more preferably 150 μm or less. Furthermore, from the viewpoint of the dissolution rate in asphalt, the particle size of the crushed material of the housing and bottle is preferably 5 mm or less, more preferably 3 mm or less, and even more preferably 1 mm or less.

[0101] (rubber) The asphalt composition of this embodiment contains resin and / or rubber. One example of rubber is crushed rubber obtained by crushing used tires. The crushed tire rubber refers to rubber with a particle size of 5 mm or less obtained by crushing tires. From the viewpoint of dissolution rate in asphalt, a particle size of 1 mm or less is preferred, and 90 to 600 μm is more preferred. From the viewpoint of achieving the Sustainable Development Goals, it is preferable to use crushed rubber from used tires, but the rubber is not limited to that and may contain other types of rubber. Examples of such other types of rubber are not particularly limited, but include natural rubber, polyisoprene rubber, polybutadiene rubber, styrene-butadiene rubber, chloroprene rubber, acrylic rubber, etc., and may also be rubber powder obtained by crushing vulcanized products thereof.

[0102] Furthermore, it is preferable that the rubber is at least one selected from the group consisting of rubber powder, fine rubber powder, rubber pellets, and rubber powder as defined in JIS K6200-2019. The rubber powder specified in JIS K6200-2019 refers to fine rubber powder, rubber powder, rubber pellets, rubber chips, and process-generated rubber obtained by crushing vulcanized rubber, in which no metal fragments, fibers, soil, or other foreign matter are visible to the naked eye. The fine rubber powder is rubber powder with a size of approximately 0.1 mm or less obtained by mechanically processing used rubber products. The rubber powder is rubber powder with a size of approximately 0.1 to 1 mm obtained by mechanically processing used rubber products. The rubber pellets are rubber powder with a size of approximately 1 mm to 10 mm obtained by mechanically processing used rubber products.

[0103] With respect to the resin and / or rubber used in the asphalt composition of this embodiment, among "amorphous resin with a glass transition temperature of 170°C or less," "crystalline resin with a melting point of 170°C or less," and "crushed tire rubber," from the viewpoint of quality stability during storage of modified asphalt, it is preferable to use "amorphous resin with a glass transition temperature of 170°C or less" and "crystalline resin with a melting point of 170°C or less."

[0104] In the asphalt composition of this embodiment, the total content of the block copolymer described above and the resin and / or rubber is 0.1 parts by mass or more and 15 parts by mass or less. From the viewpoint of improving rutting resistance after road construction, it is set to 0.1 parts by mass or more, and from the viewpoint of storage stability and processability of the asphalt composition, it is set to 15 parts by mass or less. Preferably, the amount is 0.1 parts by mass or more and 10 parts by mass or less, and more preferably 0.1 parts by mass or more and 5 parts by mass or less.

[0105] (Other additives) The asphalt composition of this embodiment may contain any petroleum resin as needed. Examples of petroleum resins include, but are not limited to, aliphatic petroleum resins such as C5 petroleum resins, aromatic petroleum resins such as C9 petroleum resins, alicyclic petroleum resins such as dicyclopentadiene petroleum resins, petroleum resins such as C5 / C9 copolymer petroleum resins, and hydrogenated petroleum resins obtained by hydrogenating these petroleum resins. There are no particular restrictions on the amount of petroleum resin used, but it is preferably 1 to 10 parts by mass, and more preferably 2 to 6 parts by mass, per 100 parts by mass of asphalt.

[0106] The asphalt composition of this embodiment may contain any additives as needed. There are no particular restrictions on the additives used, as long as they are commonly used in the formulation of thermoplastic resins and rubbery polymers. Additives include, but are not limited to, inorganic fillers such as calcium carbonate, magnesium carbonate, magnesium hydroxide, calcium sulfate, barium sulfate, silica, clay, talc, mica, wollastonite, montmorillonite, zeolite, alumina, titanium dioxide, magnesium oxide, zinc oxide, slug wool, and glass fiber; pigments such as carbon black and iron oxide; lubricants such as stearic acid, behenic acid, zinc stearate, calcium stearate, magnesium stearate, and ethylenebisstearamide; release agents, paraffin Examples include softeners and plasticizers such as phenolic process oils, naphthenic process oils, aromatic process oils, paraffin, organic polysiloxanes, and mineral oil; antioxidants such as hindered phenolic antioxidants and phosphorus-based heat stabilizers; hindered amine-based light stabilizers and benzotriazole-based ultraviolet absorbers; flame retardants, antistatic agents, reinforcing agents such as organic fibers, glass fibers, carbon fibers, and metal whiskers; colorants, other additives, or mixtures thereof, as well as those described in "Rubber and Plastic Compounding Chemicals" (edited by Rubber Digest Co., Ltd., Japan). There are no particular restrictions on the amount of additives used in the asphalt composition of this embodiment, and they can be selected as appropriate, but typically it is 50 parts by mass or less per 100 parts by mass of asphalt.

[0107] (Use of asphalt composition) The asphalt composition of this embodiment can be used in the fields of road paving, roofing and waterproofing sheets, and sealants, and is particularly suitable for use in the field of road paving.

[0108] The asphalt composition of this embodiment can be mixed with appropriate aggregate to produce an asphalt mixture for road paving. The mixing temperature between the asphalt composition and the aggregate is preferably 90°C to 200°C. A temperature of 90°C or higher allows for uniform mixing of the aggregate and the asphalt composition, while a temperature of 200°C or lower prevents decomposition and crosslinking of the asphalt composition. When the asphalt composition of this embodiment is used as an asphalt mixture for road paving, the asphalt mixture for road paving can be manufactured at a paving mixture manufacturing plant in the same way as general paving mixtures. Both continuous and batch-type mixing and stirring mixers can be used. One mixing method involves first adding aggregate heated to 90°C to 200°C to a mixer, dry-mixing for 20 to 30 seconds, then adding asphalt composition heated to the same temperature as the aggregate, and mixing for 40 to 60 seconds.

[0109] While not limited to the following, aggregates conforming to the "Asphalt Pavement Guidelines" issued by the Japan Road Association can be used. Other materials such as various low-grade aggregates and recycled aggregates may also be used. For example, in addition to crushed stone, pebbles, gravel, and steel slag, other similar granular materials such as artificially fired aggregate, fired foamed aggregate, artificial lightweight aggregate, ceramic granules, luxovite, aluminum granules, plastic granules, ceramics, emery, construction waste, and fibers can also be used. Aggregates are generally classified into coarse aggregate, fine aggregate, and filler. Coarse aggregate is aggregate that remains on a 2.36 mm sieve and generally includes types such as No. 7 crushed stone with a particle size range of 2.5 to 5 mm, No. 6 crushed stone with a particle size range of 5 to 13 mm, No. 5 crushed stone with a particle size range of 13 to 20 mm, and No. 4 crushed stone with a particle size range of 20 to 30 mm. In this embodiment, however, aggregates made by mixing one or more of these coarse aggregates with various particle sizes, or synthesized aggregates, can be used. These coarse aggregates may be coated with straight asphalt at a concentration of about 0.3 to 1% by mass relative to the aggregate.

[0110] The aforementioned fine aggregate refers to aggregate that passes through a 2.36 mm sieve and is stopped by a 0.075 mm sieve, and is not limited to the following, but examples include river sand, hill sand, mountain sand, sea sand, crushed sand, fine sand, screenings, crushed stone dust, silica sand, artificial sand, glass cullet, foundry sand, recycled aggregate crushed sand, etc.

[0111] Furthermore, the filler mentioned above is something that can pass through a 0.075 mm sieve and is not limited to the following, but examples include the filler component of screenings, stone powder, slaked lime, cement, incinerator ash, clay, talc, fly ash, carbon black, etc. In addition, rubber powder, cork powder, wood powder, resin powder, fiber powder, pulp, artificial aggregate, etc., can also be used as a filler as long as they can pass through a 0.075 mm sieve.

[0112] When preparing a road pavement asphalt mixture using the asphalt composition of this embodiment, the aggregate particle size and the amount of asphalt composition can be selected in accordance with, for example, the "Types and Particle Size Ranges of Asphalt Mixtures" described on page 92 of the "Asphalt Pavement Guidelines," published by the Japan Road Association in December 1992. For example, a road pavement asphalt mixture consisting of 2 to 15% by mass of asphalt composition and 85 to 98% by mass of aggregate is preferred.

[0113] The block copolymer used in the asphalt composition of this embodiment can also be suitably used as a material for compositions for asphalt waterproofing sheets. By using the block copolymer described above, the fatigue fracture resistance, weather resistance, crack resistance at low temperatures, resistance to shearing and sagging at high temperatures, and load resistance of asphalt waterproofing sheets can be further improved. When using the above-mentioned block copolymer as a material for the composition of an asphalt waterproofing sheet, the amount of block copolymer added is preferably more than when used in asphalt mixtures for road paving, from the viewpoint of high flexibility, crack resistance at lower temperatures, resistance to shearing and sagging at higher temperatures, high fatigue bending, and weather resistance. It is preferable that the proportion of block copolymer be 5% by mass or more, more preferably 7% by mass or more, and even more preferably 9% by mass or more, based on 100% by mass of the total of asphalt and block copolymer. On the other hand, from the viewpoint of manufacturability and economic efficiency of compositions for asphalt waterproofing sheets, it is preferable that the proportion of block copolymer be 15% by mass or less, and more preferably 13% by mass or less, relative to 100% by mass of the total of asphalt and block copolymer.

[0114] In addition to the block copolymer described above, the materials for the composition for asphalt waterproofing sheets may optionally contain various polymers, tackifiers, softeners, antioxidants, weathering agents, inorganic fillers, lubricants, release agents, and crosslinking agents. When installing asphalt waterproofing sheets at room temperature, it is preferable to use asphalt that has high low-temperature usability, low viscosity of the asphalt waterproofing sheet composition, high workability, and a high degree of penetration. In such cases, asphalt with a penetration degree of 80 (1 / 10 mm) or higher is preferred, 100 (1 / 10 mm) or higher is more preferred, 130 (1 / 10 mm) or higher is even more preferred, and 160 (1 / 10 mm) or higher is even more preferred.

[0115] When installing asphalt waterproofing sheets at high temperatures, such as using a torch method, it is preferable to use a lower penetration degree than when installing at room temperature, in order to prevent the viscosity of the composition for the asphalt waterproofing sheets from becoming too low. For example, a penetration degree of 30 (1 / 10 mm) or more and 150 (1 / 10 mm) or less is preferable, 60 (1 / 10 mm) or more and 120 (1 / 10 mm) or less is preferable, and 80 (1 / 10 mm) or more and 100 (1 / 10 mm) or less is even preferable.

[0116] When high low-temperature usability of asphalt waterproofing sheets, low viscosity of the asphalt waterproofing sheet composition, and high workability are required, it is preferable to add a softening agent. From the viewpoint of the magnitude of the effect, it is preferable to use oil as the softening agent, and process oil is more preferable. In addition, inorganic fillers may be used as needed.

[0117] The following are some examples of methods for installing asphalt waterproofing sheets, but they are not limited to the above. Examples include the hot application method, the torch application method, the self-adhesive application method, and the composite application method. The above-mentioned composition for asphalt waterproofing sheets using block copolymers has high heat aging resistance and can therefore be suitably used in hot application methods and torch application methods.

[0118] [Method for producing asphalt composition] The method for producing the asphalt composition of this embodiment is: 85-99 parts by mass of asphalt, 0.1 to 15 parts by mass of block copolymer, Resin and / or rubber, less than 0 to 15 parts by mass, The process includes a step of mixing the ingredients. The block copolymer comprises a polymer block (A) mainly composed of vinyl aromatic monomer units, and a polymer block (B) containing conjugated diene monomer units and vinyl aromatic monomer units. The resin is a resin other than the block copolymer, and is an amorphous resin with a glass transition temperature of 170°C or lower, or a crystalline resin with a melting point of 170°C or lower. The rubber is a vulcanized product of at least one rubber selected from the group consisting of polybutadiene rubber, styrene-butadiene rubber, natural rubber, and polyisoprene rubber.

[0119] Any of the above-mentioned asphalt, block copolymer, resin, and / or rubber may be used.

[0120] The mixing method is not particularly limited, and a method of heating, melting, and kneading each component using a known mixer, hot melting vessel, kneader, etc., to achieve uniform mixing can be applied. For example, the asphalt composition of this embodiment can be produced by immersing asphalt in a hot melting vessel at 160°C to 200°C (usually around 180°C), melting it completely, adding block copolymer, resin and / or rubber, and other predetermined additives while stirring with a stirrer such as a homomixer, and then increasing the stirring speed and kneading the mixture. In particular, during the mixing process, heating the mixture at 160°C to 180°C is preferable from the viewpoint of preventing thermal degradation of the asphalt and the melting rate of the resin, more preferably at 170°C to 180°C, and even more preferably at 180°C.

[0121] The normal stirring speed can be selected appropriately depending on the equipment used, but it is usually between 100 rpm and 8,000 rpm, and the stirring time is preferably 30 minutes to 6 hours, more preferably 1 to 3 hours.

[0122] When adding irregularly shaped resins, such as crushed film, as the resin, it is preferable that the agitator rotation speed be 5000 rpm or higher. By increasing the rotation speed to 5000 rpm or higher, the shear force applied to the crushed film increases, making it easier to mix into the asphalt.

[0123] When adding crushed tire powder as a rubber component, it is preferable that the agitator rotation speed be 5000 rpm or higher to finely disperse the crushed tire powder in the asphalt. Since the crushed tire powder is a vulcanized material and does not easily melt in asphalt, it can be dispersed in the asphalt by increasing the shear force at an agitation speed of 5000 rpm or higher.

[0124] Alternatively, prior to adding the block copolymer and resin and / or rubber to the molten asphalt, the block copolymer and resin and / or rubber may be pre-mixed and prepared as a masterbatch.

[0125] (Masterbatch) The masterbatch of this embodiment is The material contains a block copolymer and a resin and / or rubber, wherein the block copolymer comprises at least a polymer block (A) mainly composed of vinyl aromatic monomers and a polymer block (B) containing conjugated diene monomer units and vinyl aromatic monomer units. The block copolymer content in the masterbatch is 10% by mass or more and 90% by mass or less. The resin is an amorphous resin with a glass transition temperature of 170°C or lower, or a crystalline resin with a melting point of 170°C or lower, and the content of the resin in the masterbatch is 10% by mass or more and 90% by mass or less. The rubber is at least one selected from the group consisting of vulcanized polybutadiene rubber, styrene-butadiene rubber, natural rubber, and polyisoprene rubber, and the rubber content in the masterbatch is 10% by mass or more and 90% by mass or less.

[0126] Any of the above-mentioned asphalt, block copolymer, resin, and / or rubber may be used.

[0127] The method for manufacturing the masterbatch is not particularly limited, and any known method of heating, melting, kneading, and homogenizing using a mixer, twin-screw extruder, single-screw extruder, kneader, laboplast mill, Banbury mixer, roll, etc., can be applied. The temperature at which the mixture is heated, melted, and kneaded is preferably above the melting point of the resin (170°C), and more preferably above 180°C. By pre-forming a masterbatch of the block copolymer, resin and / or rubber, and a predetermined additive, the block copolymer, resin and / or rubber become uniform, and the dissolution rate in asphalt can be increased.

[0128] The content of the block copolymer in the masterbatch is preferably 10% by mass or more and 90% by mass or less, more preferably 20% by mass or more and 90% by mass or less, and even more preferably 30% by mass or more and 90% by mass or less. By setting the values ​​within the above range, the viscosity of the asphalt composition is reduced, improving processability, and an asphalt composition with an excellent balance of compatibility with resins can be obtained.

[0129] Furthermore, the resin content in the masterbatch is preferably 10% by mass or more and 90% by mass or less, more preferably 10% by mass or more and 70% by mass or less, even more preferably 10% by mass or more and 50% by mass or less, and even more preferably 10% by mass or more and 30% by mass or less. By setting the values ​​within the above range, the uneven dispersion of the resin tends to be made more uniform, improving the storage stability of the asphalt composition.

[0130] Furthermore, the rubber content in the masterbatch is preferably 10% by mass or more and 90% by mass or less, more preferably 10% by mass or more and 70% by mass or less, even more preferably 10% by mass or more and 50% by mass or less, and even more preferably 10% by mass or more and 30% by mass or less. By setting the values ​​within the above range, excellent recovery properties of the asphalt composition and aggregate peeling resistance after road construction can be obtained.

[0131] From the viewpoint of reducing melt viscosity (improving processability), the masterbatch content in the asphalt composition of this embodiment is preferably 0.1% to 15% by mass, more preferably 1% to 10% by mass, and even more preferably 5% to 10% by mass, based on 100% by mass of the asphalt composition of this embodiment.

[0132] [Method for manufacturing asphalt mixture for road paving] The asphalt composition of this embodiment can be used to produce an asphalt mixture for road paving. Asphalt mixtures for road paving can be produced by the plant mix method and the premix method, but the premix method is preferred from the viewpoint of resin compatibility and suppressing the amount of plastic generated from paved roads. Here, the plant mix method is a method of producing asphalt mixture for road paving by simultaneously mixing straight asphalt, block copolymer, resin and / or rubber, aggregate, and other additives at approximately 180°C. On the other hand, the premix method is a method of producing asphalt mixture for road paving by first melting and kneading straight asphalt, block copolymer, resin and / or rubber, and other additives in advance before mixing with aggregate, and then mixing the aggregate and asphalt composition. [Examples]

[0133] The present invention will be described in detail below with reference to specific examples and comparative examples, but the present invention is not limited in any way by the following examples and comparative examples. The measurement methods for the block copolymer and asphalt composition in the examples and comparative examples are as follows.

[0134] [Measurement method] <Content of vinyl aromatic monomer units in block copolymer (styrene content)> A certain amount of block copolymer (referred to as polymer in Tables 1 to 3 below) was dissolved in chloroform and measured using a UV spectrophotometer (Shimadzu Corporation, UV-2450). The content of vinyl aromatic monomer units (styrene) was calculated using a calibration curve based on the peak intensity at the absorption wavelength (262 nm) attributed to vinyl aromatic compounds (styrene).

[0135] <Content of polymer block (A) in block copolymer> Using the block copolymer before hydrogenation, the content of polymer block (A) was measured by the osmium tetroxide method described in IM Kolthoff, et. al, J. Polym. Sci. 1, p.429 (1946). A 0.1 g / 125 mL tertiary butanol solution of osmium acid was used to decompose the block copolymer.

[0136] <Amount of vinyl bonds in block copolymer, hydrogenation rate of double bonds in conjugated diene monomer units, structure in which conjugated diene monomer units derived from 1,2-bonds and / or 3,4-bonds are hydrogenated (hydrogenated vinyl) (a1), structure in which conjugated diene monomer units derived from 1,2-bonds and / or 3,4-bonds are not hydrogenated (unhydrogenated vinyl) (a2), structure in which conjugated diene monomer units derived from 1,4-bonds are hydrogenated (hydrogenated alkenyl monomer units) (b1), structure in which conjugated diene monomer units derived from 1,4-bonds are not hydrogenated (unhydrogenated alkenyl monomer units) (b2)> The amount of vinyl bonds in the block copolymer, the hydrogenation rate of double bonds in the conjugated diene monomer units, hydrogenated vinyl (a1), unhydrogenated vinyl (a2), a structure in which the conjugated diene monomer units derived from 1,4-bonds are hydrogenated (b1), and a structure in which the conjugated diene monomer units derived from 1,4-bonds are not hydrogenated (b2) were measured by nuclear magnetic resonance spectroscopy (NMR) under the following conditions. The amount of vinyl bonding and the hydrogenation rate were both measured using block copolymer samples after the hydrogenation reaction. Furthermore, the hydrogenated block copolymer was recovered by precipitation in a large amount of methanol in the reaction solution after the hydrogenation reaction. Next, the hydrogenated block copolymer is extracted with acetone, and the extract is vacuum-dried. 1 It was used as a sample for 1H-NMR measurement. 1 The conditions for H-NMR measurement are described below. (Measurement conditions) Measuring instrument: JNM-LA400 (manufactured by JEOL) Solvent: Deuterated chloroform Measurement samples: Samples taken before and after hydrogenation of the polymer. Sample concentration: 50 mg / mL Observation frequency: 400MHz Chemical shift standard: TMS (tetramethylsilane) Pulse delay: 2.904 seconds Number of scans: 64 Pulse width: 45° Measurement temperature: 26℃

[0137] <Spectrum of dynamic viscoelasticity> The loss tangent (tanδ) was determined by measuring the viscoelastic spectrum using the ARES viscoelasticity measurement and analysis device (manufactured by T.A. Instrument Japan Co., Ltd., product name). The measurement sample was set on a torsion-type geometry, and measurements were taken at a strain of 0.5% and a measurement frequency of 1 Hz. This allowed us to measure the peak height of the loss tangent (tanδ) and the temperature at which that peak occurred.

[0138] <Block co-weight-average molecular weight, molecular weight distribution> The weight-average molecular weight (Mw) and molecular weight distribution (Mw / Mn) of the block polymer were measured using GPC (Geomorphic Spectroscopy) [Waters equipment]. Tetrahydrofuran was used as the solvent, and measurements were taken at a temperature of 35°C. The molecular weight of the peaks in the chromatogram was compared with a calibration curve (created using the peak molecular weight of standard polystyrene) obtained from measurements of commercially available standard polystyrene to determine the weight-average molecular weight (polystyrene-equivalent molecular weight) and the number-average molecular weight. The molecular weight distribution was then determined from the ratio of these values.

[0139] <Content of short-chain vinyl aromatic monomer polymerization moieties (short-chain styrene content)> The block copolymer was oxidatively decomposed by passing 150 mL / min of 1.5% (O3) oxygen through a dichloromethane solution. The resulting ozonide was then reduced by dropwise addition to diethyl ether mixed with lithium aluminum hydride. Next, distilled water was added dropwise to hydrolyze the mixture, potassium carbonate was added, and salting-out and filtration were performed to obtain the vinyl aromatic hydrocarbon component. This vinyl aromatic hydrocarbon component was measured by GPC. By calculating the area ratio of the peaks obtained here (peak area corresponding to the short-chain vinyl aromatic monomer polymerization portion / total peak area), the content of the short-chain vinyl aromatic monomer polymerization portion relative to 100% by mass of vinyl aromatic monomer units in the polymer block (B) contained in the block copolymer was obtained. The ozone generator used was the OT-31R-2 model manufactured by Nippon Ozone Co., Ltd., and the GPC measurement was performed using a Waters 2487 with chloroform as the solvent, at a flow rate of 1.0 mL / min, in a column oven at 35°C, using two Shodex K803L columns.

[0140] [Method for producing block copolymers] The following describes the method for producing block copolymers (referred to as polymers in the table). (Preparation of hydrogenated catalyst) Two liters of dried and purified cyclohexane were charged into a nitrogen-purged reaction vessel, and 40 mmol of bis(η5-cyclopentadienyl)titanium di-(p-tolyl) and 150 grams of 1,2-polybutadiene (approximately 85% 1,2-vinyl bond) with a molecular weight of about 1,000 were dissolved. Then, a cyclohexane solution containing 60 mmol of n-butyllithium was added and the mixture was reacted at room temperature for 5 minutes. Immediately afterward, 40 mmol of n-butanol was added and the mixture was stirred and stored at room temperature.

[0141] (Block copolymer 1) Polymerization was carried out using a stirring device with an internal volume of 10 L and a jacketed tank reactor in the following manner. Ten parts by mass of cyclohexane were placed in the reactor and the temperature was adjusted to 70°C. Then, 0.12% by mass of n-butyllithium was added relative to the total amount of monomers (the total amount of butadiene monomer and styrene monomer added to the reactor), and 0.4 moles of N,N,N',N'-tetramethylethylenediamine (hereinafter referred to as TMEDA) were added per mole of n-butyllithium. Subsequently, a cyclohexane solution containing 10 parts by mass of styrene as monomer (monomer concentration 22% by mass) was added over approximately 3 minutes, and the reaction was carried out for 30 minutes while adjusting the reactor temperature to approximately 70°C. Next, a cyclohexane solution containing 59 parts by mass of butadiene (monomer concentration 22% by mass) and a cyclohexane solution containing 21 parts by mass of styrene (monomer concentration 22% by mass) were continuously supplied to the reactor at a constant rate for 20 minutes and 10 minutes, respectively, and the specific energy (stirring power divided by the volume of reaction solution in the polymerization tank) was 0.30 kW / m². 3 The reactor was adjusted to a pressure of 0.30 MPa, and the reaction was allowed to proceed for 30 minutes. During this time, the reactor temperature was adjusted to approximately 70°C. Subsequently, a cyclohexane solution containing 10 parts by mass of styrene as a monomer (monomer concentration 22% by mass) was added over approximately 3 minutes. The reaction was then carried out for 30 minutes while adjusting the reactor temperature to approximately 70°C and the reactor pressure to 0.30 MPa to obtain a block copolymer. Next, the hydrogenation catalyst was added to the obtained block copolymer at a concentration of 90 ppm of titanium relative to the mass of the block copolymer, and a hydrogenation reaction was carried out at a hydrogen pressure of 0.7 MPa and a temperature of 65°C. After the reaction was complete, methanol was added, followed by the addition of octadecyl-3-(3,5-di-t-butyl-4-hydroxyphenyl)propionate as a stabilizer at a concentration of 0.3% by mass relative to the mass of the polymer, to obtain a hydrogenated polymer. The hydrogenation rate was 83 mol%.

[0142] (Block copolymer 2) The amount of styrene supplied in the first stage was changed to 11 parts by mass, the amount of butadiene supplied in the second stage to 55 parts by mass and 23 parts by mass of styrene, the addition time of butadiene to 30 minutes, and the amount of styrene supplied in the third stage to 11 parts by mass. Polymerization was carried out in the same manner as in block copolymer 1. Next, the hydrogenation reaction was carried out in the same manner as with block copolymer 1, except that the hydrogenation catalyst was added to the obtained block copolymer at a concentration of 95 ppm of titanium relative to the mass of the block copolymer, to obtain a hydrogenated polymer. The hydrogenation rate was 89 mol%.

[0143] (Block copolymer 3) The amount of n-butyllithium added was changed to 0.125% by mass, and the amount of styrene supplied in the first stage was changed to 12 parts by mass, the amount of butadiene supplied in the second stage to 63 parts by mass and styrene to 14 parts by mass, and the amount of styrene supplied in the third stage to 11 parts by mass. Polymerization was carried out in the same manner as in block copolymer 1. Next, the hydrogenation reaction was carried out in the same manner as with block copolymer 1, except that the above-mentioned hydrogenation catalyst was added to the obtained block copolymer at a concentration of 85 ppm of titanium relative to the mass of the block copolymer, to obtain a hydrogenated polymer. The hydrogenation rate was 66 mol%.

[0144] (Block copolymer 4) The n-butyllithium was added at a rate of 0.115% by mass, with 15 parts by mass of styrene supplied in the first stage, 51 parts by mass of butadiene and 19 parts by mass of styrene supplied in the second stage, the butadiene addition time being 35 minutes, and the specific energy being 0.38 kW / m². 3The reactor temperature was adjusted to 75°C, and the amount of styrene supplied to the third stage was changed to 15 parts by mass. Otherwise, polymerization was carried out in the same manner as for block copolymer 1. Next, a hydrogenation reaction was carried out in the same manner as with block copolymer 1, except that the above-mentioned hydrogenation catalyst was added to the obtained block copolymer at a concentration of 65 ppm of titanium relative to the mass of the polymer, to obtain a hydrogenated polymer. The hydrogenation rate was 34 mol%.

[0145] (Block copolymer 5) The amount of styrene supplied in the first stage was changed to 10 parts by mass, the amount of butadiene supplied in the second stage to 56 parts by mass and 25 parts by mass of styrene, the addition time of butadiene to 30 minutes, and the amount of styrene supplied in the third stage to 9 parts by mass. Polymerization was carried out in the same manner as in block copolymer 1. Polymer 5 was obtained without hydrogenation. The hydrogenation rate was 0 moles.

[0146] (Block copolymer 6) The amount of styrene supplied in the first stage was changed to 11 parts by mass, the amount of butadiene supplied in the second stage to 59 parts by mass and 20 parts by mass of styrene, the addition time of butadiene to 30 minutes, and the amount of styrene supplied in the third stage to 10 parts by mass. Polymerization was carried out in the same manner as in block copolymer 1. Next, the hydrogenation reaction was carried out in the same manner as with block copolymer 1, except that the hydrogenation catalyst was added to the obtained block copolymer at a concentration of 95 ppm of titanium relative to the mass of the polymer, to obtain a hydrogenated polymer. The hydrogenation rate was 85 mol%.

[0147] (Block copolymer 7) The n-butyllithium was added at a rate of 0.095% by mass. The first stage supplied 9 parts by mass of styrene, the second stage supplied 60 parts by mass of butadiene and 22 parts by mass of styrene, the butadiene was added for 30 minutes, and the specific energy was 0.44 kW / m². 3 The mixture was adjusted, and the amount of styrene supplied to the third stage was changed to 9 parts by mass. Otherwise, polymerization was carried out in the same manner as for block copolymer 1. Next, the hydrogenation reaction was carried out in the same manner as with block copolymer 1, except that the above-mentioned hydrogenation catalyst was added to the obtained block copolymer at a concentration of 95 ppm of titanium relative to the mass of the block copolymer, to obtain a hydrogenated polymer. The hydrogenation rate was 85 mol%.

[0148] (Block copolymer 8) The n-butyllithium was added at a rate of 0.080% by mass, with 11 parts by mass of styrene supplied in the first stage, 59 parts by mass of butadiene and 20 parts by mass of styrene supplied in the second stage, the butadiene addition time being 28 minutes, and the specific energy being 0.46 kW / m². 3 The mixture was adjusted, and the amount of styrene supplied to the third stage was changed to 10 parts by mass. Otherwise, polymerization was carried out in the same manner as for block copolymer 1. Next, the hydrogenation reaction was carried out in the same manner as with block copolymer 1, except that the hydrogenation catalyst was added to the obtained block copolymer at a concentration of 90 ppm of titanium relative to the mass of the block copolymer, to obtain a hydrogenated polymer. The hydrogenation rate was 80 mol%.

[0149] (Block copolymer 9) The amount of n-butyllithium added was 0.115% by mass, and the amount of styrene supplied in the first stage was changed to 11 parts by mass, the amount of butadiene supplied in the second stage to 58 parts by mass and 21 parts by mass of styrene, and the addition time of butadiene was changed to 30 minutes. Polymerization was carried out in the same manner as for block copolymer 1. Subsequently, 1,3-dimethyl-2-imidazolidinone was added in a ratio of 0.95 mol per 1 mol of n-butyllithium, and the mixture was reacted for 25 minutes. Next, the hydrogenation reaction was carried out in the same manner as block copolymer 1, except that the hydrogenation catalyst was added to the obtained block copolymer at a concentration of 90 ppm of titanium relative to the mass of the polymer, to obtain a hydrogenated polymer. The hydrogenation rate was 84 mol%.

[0150] (Block copolymer 10) The amount of n-butyllithium added was 0.095% by mass. The amount of styrene supplied in the first stage was changed to 11 parts by mass, the amount of butadiene supplied in the second stage to 58 parts by mass and 21 parts by mass of styrene, and the addition time of butadiene was changed to 30 minutes. Polymerization was carried out in the same manner as for block copolymer 1. Subsequently, 1,3-dimethyl-2-imidazolidinone was added in a ratio of 0.95 mol per 1 mol of n-butyllithium, and the mixture was reacted for 25 minutes. Next, 95 ppm of a hydrogenation catalyst was added to the obtained block copolymer. The rest of the polymerization was carried out in the same manner as block polymer 1. Next, the hydrogenation reaction was carried out in the same manner as with block copolymer 1, except that the hydrogenation catalyst was added to the obtained block copolymer at a concentration of 80 ppm of titanium relative to the mass of the polymer, to obtain a hydrogenated polymer. The hydrogenation rate was 64 mol%.

[0151] (Block copolymer 11) The amount of n-butyllithium added was set to 0.125% by mass. The amount of styrene supplied in the first stage was changed to 23 parts by mass, the amount of butadiene supplied in the second stage to 50 parts by mass and 5 parts by mass of styrene, the addition time of butadiene to 30 minutes, and the amount of styrene supplied in the third stage to 22 parts by mass. Polymerization was carried out in the same manner as for block copolymer 1. Next, the obtained block copolymer was subjected to a hydrogenation reaction in the same manner as block copolymer 1 to obtain a hydrogenated polymer. The hydrogenation rate was 84 moles.

[0152] (Block copolymer 12) The first stage supplies 9 parts by mass of styrene, the second stage supplies 60 parts by mass of butadiene and 22 parts by mass of styrene, the butadiene addition time is 8 minutes, the third stage supplies 9 parts by mass of styrene, and the specific energy is 0.42 kW / m³. 3 Polymerization was carried out in the same manner as block copolymer 1, except for adjustments made to the polymer. Next, the hydrogenation reaction was carried out in the same manner as with block copolymer 1, except that the hydrogenation catalyst was added to the obtained block copolymer at a concentration of 85 ppm of titanium relative to the mass of the polymer, to obtain a hydrogenated polymer. The hydrogenation rate was 75 mol%.

[0153] (Block copolymer 13) 13 parts by mass of styrene supplied to the first stage, 52 parts by mass of butadiene supplied to the second stage, 22 parts by mass of styrene, the addition time of butadiene was adjusted to 30 minutes, and the temperature in the reactor was adjusted to 75°C. The styrene supplied to the third stage was changed to 13 parts by mass. Polymerization was carried out in the same manner as in Block copolymer 1 for the rest. Next, a hydrogenation reaction was carried out on the obtained block copolymer in the same manner as in Block copolymer 1, except that the above hydrogenation catalyst was added at 100 ppm as titanium based on the mass of the polymer, to obtain a hydrogenated polymer. The hydrogenation rate was 96 mol%.

[0154] (Block copolymer 14) The amount of monomers and the like supplied to the reactor was changed to obtain a block copolymer in the same manner as in Block copolymer 1. The supply amount of n-butyllithium was added at 0.13% by mass, 50 parts by mass of butadiene supplied to the second stage, 30 parts by mass of styrene, the addition time of butadiene was 40 minutes, the temperature in the reactor was 85°C, and the pressure in the reactor was adjusted to 0.42 MPa. The specific energy was adjusted to 0.35 kw / m 3 Polymerization was carried out in the same manner as in Block copolymer 1 for the rest. Next, a hydrogenation reaction was carried out on the obtained block copolymer in the same manner as in Block copolymer 1, except that the above hydrogenation catalyst was added at 85 ppm as titanium based on the mass of the polymer, to obtain a hydrogenated polymer. The hydrogenation rate was 70 mol%.

[0155] (Block copolymer 15) The supply amount of n-butyllithium was added at 0.125% by mass, 20 parts by mass of styrene supplied to the first stage, 61 parts by mass of butadiene supplied to the second stage, styrene was not added, and the styrene supplied to the third stage was changed to 19 parts by mass. Polymerization was carried out in the same manner as in Block copolymer 1 for the rest. A hydrogenation reaction was not carried out, and Block copolymer 15 was obtained. The hydrogenation rate was 0 mol%.

[0156] (Block copolymer 16) Using a jacketed tank reactor, a predetermined amount of cyclohexane was charged into the reactor, and the temperature inside the reactor was adjusted to 60 °C. Thereafter, n-butyllithium was added from the bottom of the reactor so as to be 0.12 parts by mass with respect to 100 parts by mass of all the monomers (total amount of butadiene monomer and styrene monomer charged into the reactor). Furthermore, a cyclohexane solution of N,N,N’,N’-tetramethylethylenediamine was added so as to be 0.40 mol with respect to 1 mol of n-butyllithium. Thereafter, as a monomer and as the first-step polymerization reaction, a cyclohexane solution containing 10 parts by mass of styrene (monomer concentration 15% by mass) was supplied over about 10 minutes, and the temperature inside the reactor was adjusted to 65 °C. After the supply was stopped, the reaction was carried out for 15 minutes. Next, as the second-step polymerization reaction, a cyclohexane solution containing 57 parts by mass of butadiene (monomer concentration 15% by mass) and a cyclohexane solution containing 23 parts by mass of styrene (monomer concentration 15% by mass) were continuously supplied to the reactor at a constant rate over 60 minutes, and the specific energy was adjusted to 0.30 kw / m 3 The reaction was carried out with the internal pressure of the reactor adjusted to 0.30 MPa. After the supply was stopped, the reaction was carried out for 15 minutes. Next, as the third-step polymerization reaction, a cyclohexane solution containing 10 parts by mass of styrene (monomer concentration 15% by mass) was supplied over about 10 minutes, and the temperature inside the reactor was adjusted to 65 °C. After the supply was stopped, the reaction was carried out for 15 minutes. Next, the obtained block copolymer was added with the above hydrogenation catalyst at 100 ppm as titanium with respect to the mass of the polymer, and a hydrogenation reaction was carried out at a hydrogen pressure of 0.7 MPa and a temperature of 65 °C. After the reaction was completed, an aqueous methanol solution was added, and then octadecyl-3-(3,5-di-t-butyl-4-hydroxyphenyl)propionate was added as a stabilizer at 0.1% by mass with respect to the mass of the polymer to obtain Block Copolymer 16. The hydrogenation rate was 99 mol%.

[0157] (Block Copolymer 17) n-butyllithium is added from the bottom of the reactor in an amount of 0.085 parts by mass per 100 parts by mass of total monomers (the total amount of butadiene monomer and styrene monomer added to the reactor), the polymerization temperature is set to 55°C, the first step is a cyclohexane solution containing 11 parts by mass of styrene (monomer concentration 15% by mass), and the second step is a cyclohexane solution containing 58 parts by mass of butadiene (monomer concentration 15% by mass) and 20 parts by mass of styrene (monomer concentration 15% by mass), with a specific energy of 0.35 kW / m³. 3 The mixture was adjusted, and in the third step, a cyclohexane solution containing 11 parts by mass of styrene (monomer concentration 15% by mass) was used, and 95 ppm of hydrogenation catalyst was added. The rest of the polymerization was carried out in the same manner as block copolymer 16 to obtain block copolymer 17. The hydrogenation rate was 91 mol%.

[0158] (Block copolymer 18) n-butyllithium is added from the bottom of the reactor in an amount of 0.125 parts by mass per 100 parts by mass of the total monomers (the total amount of butadiene monomer and styrene monomer added to the reactor), the polymerization temperature is set to 65°C, the first step is a cyclohexane solution containing 11 parts by mass of styrene (monomer concentration 15% by mass), and the second step is a cyclohexane solution containing 45 parts by mass of butadiene (monomer concentration 15% by mass) and a cyclohexane solution containing 33 parts by mass of styrene (monomer concentration 15% by mass), with a specific energy of 0.25 kW / m³. 3 The mixture was adjusted, and the third step involved a cyclohexane solution containing 11 parts by mass of styrene (monomer concentration 15% by mass). The rest of the polymerization was carried out in the same manner as block copolymer 16 to obtain block copolymer 18. The hydrogenation rate was 96 mol%.

[0159] (Block copolymer 19) n-butyllithium is added from the bottom of the reactor in an amount of 0.115 parts by mass per 100 parts by mass of the total monomers (the total amount of butadiene monomer and styrene monomer added to the reactor), the polymerization temperature is set to 65°C, the first step is a cyclohexane solution containing 18 parts by mass of styrene (monomer concentration 15% by mass), and the second step is a cyclohexane solution containing 50 parts by mass of butadiene (monomer concentration 15% by mass) and 14 parts by mass of styrene (monomer concentration 15% by mass), with a specific energy of 0.32 kW / m³. 3 The mixture was adjusted, and the third step involved a cyclohexane solution containing 18 parts by mass of styrene (monomer concentration 15% by mass). The rest of the polymerization was carried out in the same manner as block copolymer 16 to obtain block copolymer 19. The hydrogenation rate was 97 mol%.

[0160] (Block copolymer 20) n-butyllithium is added from the bottom of the reactor in an amount of 0.125 parts by mass per 100 parts by mass of total monomers (the total amount of butadiene monomer and styrene monomer added to the reactor), the polymerization temperature is set to 65°C, the first step is a cyclohexane solution containing 11 parts by mass of styrene (monomer concentration 20% by mass), and the second step is a cyclohexane solution containing 57 parts by mass of butadiene (monomer concentration 20% by mass) and a cyclohexane solution containing 21 parts by mass of styrene (monomer concentration 20% by mass) are supplied in three separate batches at 15-minute intervals, with a specific energy of 0.32 kW / m³. 3 The mixture was adjusted, and the third step involved a cyclohexane solution containing 11 parts by mass of styrene (monomer concentration 20% by mass). The rest of the polymerization was carried out in the same manner as block copolymer 16 to obtain block copolymer 20. The hydrogenation rate was 99 mol%.

[0161] (Block copolymer 21) In the first step, a cyclohexane solution containing 10 parts by mass of styrene (monomer concentration 25% by mass) was prepared. In the second step, a cyclohexane solution containing 60 parts by mass of butadiene (monomer concentration 25% by mass) and a cyclohexane solution containing 21 parts by mass of styrene (monomer concentration 25% by mass) were added over 10 minutes, resulting in a specific energy of 0.32 kW / m². 3 The mixture was adjusted, and the third step involved a cyclohexane solution containing 9 parts by mass of styrene (monomer concentration 25% by mass). The rest of the polymerization was carried out in the same manner as block copolymer 16 to obtain block copolymer 21. The hydrogenation rate was 95 mol%.

[0162] (Block copolymer 22) n-butyllithium is added from the bottom of the reactor in an amount of 0.125 parts by mass per 100 parts by mass of the total monomers (the total amount of butadiene monomer and styrene monomer added to the reactor), the polymerization temperature is set to 56°C, the first step is a cyclohexane solution containing 11 parts by mass of styrene (monomer concentration 15% by mass), and the second step is a cyclohexane solution containing 57 parts by mass of butadiene (monomer concentration 15% by mass) and a cyclohexane solution containing 21 parts by mass of styrene (monomer concentration 15% by mass) are continuously supplied to the reactor at a constant rate over 55 minutes, resulting in a specific energy of 0.32 kW / m³. 3 The reactor pressure was adjusted to 0.25 MPa and the reaction was carried out. In the third step, a cyclohexane solution containing 11 parts by mass of styrene (monomer concentration 15% by mass) was used. The rest of the polymerization was carried out in the same manner as block copolymer 16 to obtain block copolymer 22. The hydrogenation rate was 95 mol%.

[0163] (Block copolymer 23) n-butyllithium is added from the bottom of the reactor in an amount of 0.085 parts by mass per 100 parts by mass of total monomers (the total amount of butadiene monomer and styrene monomer added to the reactor), the polymerization temperature is set to 50°C, the first step is a cyclohexane solution containing 17 parts by mass of styrene (monomer concentration 15% by mass), the reactor temperature is set to 53°C, the second step is a cyclohexane solution containing 43 parts by mass of butadiene (monomer concentration 15% by mass) and a cyclohexane solution containing 24 parts by mass of styrene (monomer concentration 15% by mass) are continuously supplied to the reactor at a constant rate over 55 minutes, and the specific energy is 0.42 kW / m³. 3 The reactor pressure was adjusted to 0.15 MPa and the reaction was carried out. The third step involved a cyclohexane solution containing 16 parts by mass of styrene (monomer concentration 15% by mass). The rest of the polymerization was carried out in the same manner as block copolymer 16 to obtain block copolymer 23. The hydrogenation rate was 98 mol%.

[0164] (Block copolymer 24) n-butyllithium is added from the bottom of the reactor in an amount of 0.100 parts by mass per 100 parts by mass of the total monomers (the total amount of butadiene monomer and styrene monomer added to the reactor), the polymerization temperature is set to 57°C, and in the second step, a cyclohexane solution containing 60 parts by mass of butadiene (monomer concentration 15% by mass) and a cyclohexane solution containing 20 parts by mass of styrene (monomer concentration 15% by mass) are continuously supplied to the reactor at a constant rate for 57 minutes, and the specific energy is 0.42 kW / m³. 3 The mixture was adjusted to the specified ratio. The rest was polymerized in the same manner as block copolymer 16 to obtain block copolymer 24. The hydrogenation rate was 97 mol%.

[0165] (Block copolymer 25) n-butyllithium is added from the bottom of the reactor in an amount of 0.080 parts by mass per 100 parts by mass of the total monomers (the total amount of butadiene monomer and styrene monomer added to the reactor), the polymerization temperature is set to 56°C, and in the second step, a cyclohexane solution containing 60 parts by mass of butadiene (monomer concentration 15% by mass) and a cyclohexane solution containing 20 parts by mass of styrene (monomer concentration 15% by mass) are continuously supplied to the reactor at a constant rate for 59 minutes, and the specific energy is 0.46 kW / m³. 3 The mixture was adjusted to the specified ratio. The rest was polymerized in the same manner as block copolymer 16 to obtain block copolymer 25. The hydrogenation rate was 97 mol%.

[0166] (Block copolymer 26) n-butyllithium is added from the bottom of the reactor in an amount of 0.085 parts by mass per 100 parts by mass of the total monomers (the total amount of butadiene monomer and styrene monomer added to the reactor), the polymerization temperature is set to 55°C, the first step is a cyclohexane solution containing 11 parts by mass of styrene (monomer concentration 15% by mass), and the second step is a cyclohexane solution containing 59 parts by mass of butadiene (monomer concentration 15% by mass) and 20 parts by mass of styrene (monomer concentration 15% by mass), with a specific energy of 0.35 kW / m³. 3 The mixture was adjusted and polymerization was carried out. Next, 95 ppm of a hydrogenation catalyst was added to the obtained block copolymer. The rest of the polymerization was carried out in the same manner as block copolymer 16 to obtain block copolymer 26. The hydrogenation rate was 92 mol%.

[0167] (Block copolymer 27) n-butyllithium is added from the bottom of the reactor in an amount of 0.130 parts by mass per 100 parts by mass of total monomers (the total amount of butadiene monomer and styrene monomer added to the reactor), the polymerization temperature is set to 85°C, the first step is a cyclohexane solution containing 8 parts by mass of styrene (monomer concentration 15% by mass), and the second step is a cyclohexane solution containing 50 parts by mass of butadiene (monomer concentration 15% by mass) and a cyclohexane solution containing 35 parts by mass of styrene (monomer concentration 15% by mass) are continuously supplied to the reactor at a constant rate over 60 minutes, resulting in a specific energy of 0.08 kW / m³. 3 The reactor pressure was adjusted to 0.32 MPa and the reaction was carried out. In the third step, a cyclohexane solution containing 7 parts by mass of styrene (monomer concentration 15% by mass) was used. The rest of the polymerization was carried out in the same manner as block copolymer 16 to obtain block copolymer 27. The hydrogenation rate was 98 mol%.

[0168] (Block copolymer 28) n-butyllithium is added from the bottom of the reactor in an amount of 0.140 parts by mass per 100 parts by mass of total monomers (the total amount of butadiene monomer and styrene monomer added to the reactor), the polymerization temperature is set to 56°C, the first step is a cyclohexane solution containing 11 parts by mass of styrene (monomer concentration 15% by mass), and the second step is a cyclohexane solution containing 59 parts by mass of butadiene (monomer concentration 15% by mass) and a cyclohexane solution containing 19 parts by mass of styrene (monomer concentration 15% by mass) are continuously supplied to the reactor at a constant rate over 55 minutes, resulting in a specific energy of 0.09 kW / m³. 3 The reactor pressure was adjusted to 0.25 MPa and the reaction was carried out. In the third step, a cyclohexane solution containing 11 parts by mass of styrene (monomer concentration 15% by mass) was used. The rest of the polymerization was carried out in the same manner as block copolymer 16 to obtain block copolymer 28. The hydrogenation rate was 98 mol%.

[0169] (Block copolymer 29) n-Butyllithium was added from the bottom of the reactor so as to be 0.080 parts by mass with respect to 100 parts by mass of all the monomers (total amount of butadiene monomer and styrene monomer charged into the reactor), the polymerization temperature was set at 55°C, the first step was a cyclohexane solution containing 10 parts by mass of styrene (monomer concentration 15% by mass), the second step was a cyclohexane solution containing 57 parts by mass of butadiene (monomer concentration 15% by mass) and a cyclohexane solution containing 24 parts by mass of styrene (monomer concentration 15% by mass), and the specific energy was adjusted to 0.35 kw / m 3

[0170] (Block copolymer 30) n-Butyllithium was added from the bottom of the reactor so as to be 0.085 parts by mass with respect to 100 parts by mass of all the monomers (total amount of butadiene monomer and styrene monomer charged into the reactor), the polymerization temperature was set at 55°C, the first step was a cyclohexane solution containing 11 parts by mass of styrene (monomer concentration 15% by mass), the second step was a cyclohexane solution containing 58 parts by mass of butadiene (monomer concentration 15% by mass) and a cyclohexane solution containing 20 parts by mass of styrene (monomer concentration 15% by mass), and the specific energy was adjusted to 0.39 kw / m 3

[0171] (Block copolymer 31)(Block copolymer 31) Step 1 involved using a cyclohexane solution containing 17 parts by mass of styrene (monomer concentration 15% by mass). Step 2 involved continuously supplying a cyclohexane solution containing 67 parts by mass of butadiene (monomer concentration 15% by mass) to the reactor at a constant rate for 60 minutes, followed by a 15-minute reaction after the supply was stopped. Step 3 involved using a cyclohexane solution containing 16 parts by mass of styrene (monomer concentration 15% by mass), and no hydrogenation reaction was performed. The rest of the polymerization was carried out in the same manner as block copolymer 16 to obtain block copolymer 31. The hydrogenation rate was 0 mol%.

[0172] (Block copolymer 32) Polymerization was carried out using a tank-type reactor (internal volume 10L) equipped with a stirring device and a jacket, in the following manner. Ten parts by mass of cyclohexane were placed in the reactor, and the temperature was adjusted to 70°C. Then, 0.065% by mass of n-butyllithium was added relative to the total amount of monomers (the total amount of butadiene monomer and styrene monomer added to the reactor), and 1.5 moles of TMEDA were added per mole of n-butyllithium. Subsequently, a cyclohexane solution containing 4 parts by mass of styrene as monomer (monomer concentration 20% by mass) was added over approximately 3 minutes, and the reaction was carried out for 15 minutes while adjusting the reactor temperature to 70°C. Next, a cyclohexane solution containing 50% by mass of butadiene (monomer concentration 20% by mass) and a cyclohexane solution containing 42% by mass of styrene (monomer concentration 20% by mass) were continuously supplied to the reactor at a constant rate for 20 minutes and 15 minutes, respectively. The reactor internal pressure was set to 0.30 MPa, and the reaction was carried out for 50 minutes. During this time, the temperature inside the reactor was adjusted to 70°C. Subsequently, a cyclohexane solution containing 4 parts by mass of styrene as a monomer (monomer concentration 20% by mass) was added over approximately 3 minutes, and the reaction was carried out for 30 minutes while adjusting the reactor temperature to 70°C and the reactor internal pressure to 0.30 MPa to obtain a block copolymer. Next, the hydrogenation catalyst was added to the obtained block copolymer at a concentration of 90 ppm of titanium relative to the mass of the block copolymer, and a hydrogenation reaction was carried out at a hydrogen pressure of 0.7 MPa and a temperature of 65 degrees Celsius. After the reaction was complete, methanol was added, and then octadecyl-3-(3,5-di-t-butyl-4-hydroxyphenyl)propionate was added as a stabilizer at a concentration of 0.3% by mass relative to the mass of the block copolymer to obtain block copolymer 32, which is a hydrogenated polymer. The hydrogenation rate was 98 ml.

[0173] The physical properties of block copolymers 1 to 32 are shown in Tables 1 to 3 below.

[0174] [Table 1]

[0175] [Table 2]

[0176] [Table 3]

[0177] [Method of manufacturing a masterbatch] A masterbatch was prepared using block copolymer 3 and resin [high-density polyethylene (HDPE), Suntech HD B161, manufactured by Asahi Kasei Corporation] in the following manner. First, 95% by mass of block copolymer 3 and 5% by mass of resin [high-density polyethylene (HDPE), Suntech HD B161, manufactured by Asahi Kasei Corporation] were dry-blended. Next, the polymer and resin blend was compounded in the single-screw extruder with the temperature set to 180°C to 200°C along the entire length of the extruder. The extrusion conditions were a screw rotation speed of 90 rpm and an extrusion rate of 10 kg / h. The strands extruded from the extruder were pelletized and dried in an oven at 40°C to obtain a masterbatch (labeled MB1 in the table).

[0178] The mixing ratio of block copolymer 3 and resin was changed as shown in Table 4, and the compounds were compounded under the same conditions to prepare masterbatches (MB2-MB5).

[0179] A masterbatch was prepared using block copolymer 10 and resin [high-density polyethylene (HDPE), Suntech HD B161, manufactured by Asahi Kasei Corporation] in the following manner. First, 95% by mass of block copolymer 10 and 5% by mass of resin [high-density polyethylene (HDPE), Suntech HD B161, manufactured by Asahi Kasei Corporation] were dry-blended. Next, the temperature of the single-screw extruder was set to 180°C to 200°C along its entire length, and the block copolymer and resin blend were compounded in the single-screw extruder. The extrusion conditions were a screw rotation speed of 90 rpm and an extrusion rate of 10 kg / h. The strands extruded from the extruder were pelletized and dried in an oven at 40°C to obtain a masterbatch (labeled MB6 in Table 4).

[0180] The mixing ratio of block copolymer 10 and resin was changed as shown in Table 4, and the compounds were compounded under the same conditions to prepare masterbatches (MB7-10).

[0181] [Table 4]

[0182] [Method for manufacturing asphalt composition] ( Reference example 1-32) An asphalt composition was prepared using block copolymers 1 to 32 in the following manner. 350g of straight asphalt 80-100 (manufactured by Nippon Oil Corporation) was placed in a 750mL metal can, and the metal can was thoroughly immersed in an oil bath at 180°C. Next, 95 parts by mass of molten asphalt, 4 parts by mass of the block copolymer produced as described above, and 1 part by mass of resin [high-density polyethylene, Suntech HD B161 manufactured by Asahi Kasei Corporation] were added in small amounts while stirring. After complete addition, the mixture was stirred at a rotation speed of 5000 rpm for 120 minutes to prepare the asphalt composition.

[0183] (Comparative Example 1) 350g of straight asphalt 80-100 (manufactured by Nippon Oil Corporation) was placed in a 750mL metal can, and the metal can was thoroughly immersed in an oil bath at 180°C. Next, 95 parts by mass of molten asphalt, 4 parts by mass of styrene-butadiene thermoplastic elastomer (SBS) [Toughprene T437, manufactured by Asahi Kasei Corporation], and 1 part by mass of resin [High-density polyethylene (HDPE), Suntech HD B161, manufactured by Asahi Kasei Corporation] were added in small amounts while stirring. T437 is a styrene-butadiene-styrene block copolymer that does not have polymer blocks (B) containing aromatic monomer units and conjugated diene monomer units. After complete addition, the mixture was stirred at a rotation speed of 5000 rpm for 120 minutes to prepare the asphalt composition.

[0184] ( Reference example (33-62, Comparative Examples 2-13) Straight asphalt 80-100 [manufactured by Nippon Oil Corporation], block copolymer 3, and resin [high-density polyethylene (HDPE), Suntech HD B161 manufactured by Asahi Kasei Corporation] were kneaded under the same conditions as the above-mentioned method for producing the asphalt composition, except that the mass ratios of each component were changed as shown in Tables 8 to 11. The block copolymer to be added was changed to block copolymer 10, and an asphalt composition was prepared under the same conditions.

[0185] ( Reference example (63-92, Comparative Examples 14-24) Straight asphalt 80-100 [manufactured by Nippon Oil Corporation], block copolymer 3, and resin [low-density polyethylene (LDPE), Suntec LD M1920, manufactured by Asahi Kasei Corporation] were kneaded under the same conditions as the above-mentioned method for producing the asphalt composition, except that the mass ratios of each component were changed as shown in Tables 12 to 15. The block copolymer to be added was changed to block copolymer 10, and an asphalt composition was prepared under the same conditions.

[0186] ( Reference example 93-122, Comparative Examples 25-35) Straight asphalt 80-100 (manufactured by Nippon Oil Corporation), block copolymer 3, and resin (PE blend manufactured by Toyama Environmental Services Co., Ltd., a recycled polyethylene company) were kneaded under the same conditions as the above-mentioned method for producing the asphalt composition, except that the mass ratios of each component were changed as shown in Tables 16 to 19. The block copolymer to be added was changed to polymer 10, and an asphalt composition was prepared under the same conditions.

[0187] ( Reference example (123-152, Comparative Examples 36-46) Straight asphalt 80-100 (manufactured by Nippon Oil Corporation), block copolymer 3, and resin (ethylene vinyl acetate copolymer, Suntech EVA EF1914, manufactured by Asahi Kasei Corporation) were kneaded under the same conditions as the above-mentioned method for producing the asphalt composition, except that the mass ratios of each component were changed as shown in Tables 20 to 23. The block copolymer to be added was changed to polymer 10, and an asphalt composition was prepared under the same conditions.

[0188] ( Reference example 153-182, Comparative Examples 47-57) Straight asphalt 80-100 [manufactured by Nippon Oil Corporation], block copolymer 3, and resin [crushed material of a multilayer film consisting of polyethylene and ethylene vinyl acetate copolymer] were kneaded under the same conditions as the above-mentioned method for producing the asphalt composition, except that the mass ratios of each component were changed as shown in Tables 24 to 27. The block copolymer to be added was changed to block copolymer 10, and an asphalt composition was prepared under the same conditions.

[0189] (Examples 183-188, Comparative Examples 58-63) 90 parts by mass of molten straight asphalt 80-100 [manufactured by Nippon Oil Corporation] were mixed with 10 parts by mass of masterbatches (MB1-MB10) in small amounts while stirring. After complete addition, the mixture was expanded at a rotation speed of 5000 rpm for 120 minutes to prepare the asphalt composition. Similarly, an asphalt composition was prepared by mixing 80 parts by mass of straight asphalt 80-100 [manufactured by Nippon Oil Corporation] with 20 parts by mass each of masterbatches (MB1, MB5). These asphalt compositions are shown in Tables 28 and 29 below.

[0190] ( Reference example 189-192, Comparative Examples 64-66) Reference example In experiment 189, 7 parts by mass of block copolymer 10 and 3 parts by mass of crushed tire rubber powder were added in small amounts while stirring to 90 parts by mass of molten straight asphalt 80-100 [manufactured by Nippon Oil Corporation]. After complete addition, the mixture was expanded at a rotation speed of 5000 rpm for 120 minutes to prepare the asphalt composition. Reference example In comparative examples 190-192 and 64-66, asphalt compositions were prepared in the same manner according to the mass ratios shown in Table 30.

[0191] [Preparation of asphalt mixtures for road paving] Reference Examples 1-182, Examples 183-188, Reference Examples 189-192The asphalt compositions obtained in Comparative Examples 1 to 64 were mixed with aggregate using a 27-liter capacity heating device-equipped mixer for experimental purposes, resulting in a total mixture volume of 10 kg. A dense-graded asphalt mixture for road paving was obtained. Specifically, a mixture of No. 6 crushed stone / No. 7 crushed stone / crushed sand / fine sand / stone powder in a ratio of 36 / 19 / 27 / 12 / 6 (%) was used as aggregate, and it was mixed with 5.5 parts by mass of asphalt composition and 94.5 parts by mass of aggregate. In other words, the asphalt composition content in the road paving asphalt mixture was 5.5% by mass. The aggregates used were crushed stone and crushed sand from Iwafune-machi, Shimotsuga-gun, Tochigi Prefecture, fine sand from Sakae-machi, Inba-gun, Chiba Prefecture, and stone powder from Yamasuga-machi, Sano City, Tochigi Prefecture. The particle size distribution of the aggregate used in the manufacture of the asphalt mixture is shown in Table 31 below. The asphalt composition and aggregate were mixed according to the following procedure. First, 94.5 parts by mass of dense-grained aggregate of a predetermined particle size is placed into the mixer and dry-mixed for 25 seconds, and then, Reference Examples 1-182, Examples 183-188, Reference Examples 189-192 5.5 parts by mass of the asphalt compositions obtained in Comparative Examples 1 to 64 were put into a mixer and mixed for 50 seconds to obtain a dense-graded asphalt mixture for road paving. The mixing temperature for both the dry mixing and the final mixing was 177°C.

[0192] [Evaluation Method] The physical properties of asphalt compositions and asphalt mixtures (indicated as "Revised As Properties" and "Mixture Properties" in the table) were evaluated as follows.

[0193] (Compatibility of asphalt compositions (high-temperature storage stability)) The compatibility (high-temperature storage stability) of the asphalt composition was measured by separation tests in accordance with ASTM-D5976. The asphalt compositions obtained in the examples and comparative examples were used as samples. The sample was filled into a 2cm diameter x 15cm length Teflon® tube, covered with aluminum foil, and left to stand in an oven at 163°C for 48 hours. After that, it was left to stand in a freezer overnight, the sample was removed from the Teflon® tube, divided into three equal parts, and the softening points of the upper and lower parts were measured. The smaller the difference in the measured softening points between the upper and lower parts, the better the compatibility. Compatibility was evaluated using the following criteria, from best to worst: ◎, ○, △, ×. A rating of △ or higher was considered to indicate sufficient performance for practical use. The method for measuring the softening point will be described later. The evaluation criteria are as follows: ◎: The difference in the measured softening point between the upper and lower parts is greater than 0°C and less than or equal to 2°C. ○: The difference in the measured softening point between the upper and lower parts is greater than 2°C and less than or equal to 5°C. △: The difference in the measured softening point between the upper and lower parts is greater than 5°C and less than or equal to 10°C. ×: The difference in the measured softening point between the upper and lower parts exceeds 10°C. The compatibility of asphalt compositions tended to improve with hydrogenation of block copolymers. It was found that hydrogenation of block copolymers refined the particle size of the resin dispersions, thereby suppressing separation during storage.

[0194] (Melting viscosity (processability) of asphalt composition) The melt viscosity of the asphalt composition at 160°C was measured using a Brookfield viscometer. The asphalt compositions obtained in the examples and comparative examples were used as samples. Lower melt viscosity results in better processability, and materials were evaluated using the following criteria, from best to worst: ◎, ○, △, ×. A rating of △ or higher was considered to indicate sufficient performance for practical use. The evaluation criteria are as follows: ◎: Melt viscosity is 300 mPa·s or less ○: Melt viscosity is greater than 300 mPa·s and less than or equal to 350 mPa·s △: Melt viscosity is greater than 350 mPa·s and less than or equal to 400 mPa·s. ×: Melt viscosity exceeds 400 mPa·s The melt viscosity of the asphalt composition tended to decrease when the block copolymer content was reduced, when the total amount of block copolymer and resin added was reduced to 10 parts by mass or less, or when the amount of resin added was 1 part by mass or more.

[0195] (Softening point (heat resistance) of asphalt composition) The softening point of the asphalt composition was measured using the ring and ball method in accordance with JIS-K2207. The asphalt compositions obtained in the examples and comparative examples were used as samples. The sample was filled into a standard ring, supported horizontally in a glycerin solution, and a 3.5g sphere was placed in the center of the sample. When the solution temperature was increased at a rate of 5°C / min, the temperature (softening point) at which the sample touched the bottom plate of the ring stand due to the weight of the sphere was measured. A higher softening point is preferable, and the following criteria were used to evaluate the softening point from best to worst: ◎, ○, △, ×. A score of △ or higher was considered to indicate sufficient performance for practical use. The evaluation criteria are as follows: ◎: Temperature (softening point) is 65℃ or higher ○: Temperature (softening point) is 60°C or higher and less than 65°C △: Temperature (softening point) is between 56°C and 60°C ×: Temperature (softening point) is below 56°C It was found that the softening point of asphalt compositions tends to improve by adding 1 part by mass or more of resin, increasing the molecular weight of the block copolymer, increasing the content of vinyl aromatic monomer units, and increasing the hydrogenation rate.

[0196] (Elastic recovery of asphalt compositions) Measurements were taken in accordance with the method described in British Standards, BS EN 13398:2010 / BS 2000-516:2010. The asphalt composition prepared by the method described above was poured into a jig to create a dumbbell-shaped specimen with gripping parts at both ends. The dimensions of the specimen, excluding the gripping parts, were 1 cm thick, 1 cm wide, and 3 cm long. The gripping parts of the specimen were set in the chucks of a tensile testing machine, and the specimen was pulled at a speed of 5 cm / min from a distance of 3 cm between the chucks in a 25°C water bath, stopping when it had been stretched 20 cm from its initial length. After leaving the specimen in the 25°C water bath for 10 seconds while still clamped in the chucks, the specimen was cut in half. After that, it was left in the 25°C water bath for 30 minutes, and the sum of the lengths of the parts of both specimens excluding the gripping parts, α (cm), was measured, and the percentage calculated by the following formula (I) was defined as the tensile recovery (%). Elongation recovery (%) ={3(cm)+20(cm)-α(cm) / 20(cm)}×100...(I) Higher tensile recovery indicates superior crack resistance. The evaluation criteria are as follows: ◎: Elongation recovery rate of 80% or more ○: Elongation recovery rate is 70% or more but less than 80% △: Elongation recovery rate is 60% or more but less than 70% ×: Elongation recovery is less than 60% It was found that the elongation recovery of asphalt compositions tends to improve by increasing the content of vinyl aromatic monomer units in the block copolymer. Furthermore, it was found that performance tends to improve by increasing the amount of block copolymer added and refining the particle size of the resin dispersion.

[0197] (Low-temperature elongation of asphalt composition) The low-temperature elongation of the asphalt composition was measured in accordance with JIS-K2207. The asphalt compositions obtained in the examples and comparative examples were used as samples. The sample was poured into a mold to form the specified shape, then kept at 5°C in a constant temperature water bath. Next, the sample was pulled at a speed of 5 cm / min, and the distance it stretched before breaking (elongation) was measured. Asphalt compositions with higher elongation have better resistance to low-temperature cracking, and were evaluated from best to worst using the following criteria: ◎, ○, △, ×. A score of △ or higher was considered to be sufficient for practical use. The evaluation criteria are as follows: ◎: Elongation of 45cm or more ○: Elongation is between 40cm and 45cm △: Elongation is between 35cm and 40cm ×: Elongation less than 35cm It was found that the low-temperature elongation of asphalt compositions tends to improve by reducing the content of vinyl aromatic monomer units in the block copolymer. However, it was also found that reducing the content of vinyl aromatic monomer units tends to lower the softening point of the asphalt compositions. Furthermore, it was found that performance tends to improve by increasing the amount of block copolymer added and refining the particle size of the resin dispersion.

[0198] (Thermal stability of asphalt composition (maintenance of low-temperature elongation)) RTFOT (Rotating Thin Film Heating Test) was performed in accordance with EN12607-1. The heating time was 240 minutes, and the low-temperature elongation before and after heating was measured to determine the retention rate. Maintenance rate = (Low-temperature elongation after heating / Low-temperature elongation before heating) A higher retention rate indicates better heat resistance, leading to better long-term stability of the asphalt composition and longer lifespan for road construction using the mixture. Therefore, the following criteria were used to evaluate the composition from best to worst: ◎, ○, △, ×. △ indicates that performance is sufficient for practical use. The evaluation criteria are as follows: ◎: Maintenance rate of 90% or higher ○: Maintenance rate is 85% or more but less than 90% △: Elongation recovery rate is 80% or more but less than 85% ×: Elongation recovery is less than 80% It was found that the thermal stability of asphalt compositions tends to improve by increasing the hydrogenation rate of the block copolymer. Increasing the hydrogenation rate suppresses thermal oxidative degradation of the copolymer and improves resin dispersion, thus improving the thermal stability of the asphalt composition. However, it was found that excessively increasing the hydrogenation rate tends to increase the viscosity of the asphalt composition, leading to a decrease in processability.

[0199] (Dynamic stability of asphalt mixture (rutting resistance)) The dynamic stability (DS) of the asphalt mixture was measured by a wheel tracking test. The asphalt mixture prepared above was used as the test specimen. The wheel tracking test was conducted in accordance with Test Method Manual B003. A small, loaded rubber wheel was repeatedly moved back and forth on a test specimen of specified dimensions at a specified temperature, specified time, and specified speed. The dynamic stability (DS) (cycles / mm) was determined from the amount of deformation per unit time. The higher the dynamic stability, the better the resistance to rutting. The following criteria were used to evaluate the performance from best to worst: ◎, ○, △, ×. A rating of △ or higher was considered to indicate sufficient performance for practical use. The evaluation criteria are as follows: ◎: Dynamic stability (DS) of 2000 cycles / mm or higher ○: Dynamic stability (DS) is between 1500 cycles / mm and less than 2000 cycles / mm △: Dynamic stability (DS) is between 1000 cycles / mm and less than 1500 cycles / mm ×: Dynamic stability (DS) is less than 1000 cycles / mm It was found that the dynamic stability of asphalt mixtures tends to improve by increasing the molecular weight of the block copolymer and increasing the content of vinyl aromatic monomer units. Furthermore, it was found that increasing the amount of resin added tended to improve performance. However, it was also found that excessively increasing the amount of resin added tended to decrease the storage stability of the asphalt composition and increase the amount of plastic generated from the asphalt mixture, as described later.

[0200] (Amount of resin generated) The amount of resin generated was measured by a wheel tracking test. The asphalt mixture prepared above was used as the test specimen. The wheel tracking test was conducted in accordance with Test Method Manual B003. A small, loaded rubber wheel was repeatedly moved back and forth on a test specimen of specified dimensions at a specified temperature, time, and speed. The accumulated wear debris was then collected and weighed, and this was defined as the "amount of resin generated." This indicates that the less resin is generated, the less resin is released from paved roads, thus suppressing resin scattering. The evaluation criteria are as follows: ◎: Plastic waste generated is 0g or more but less than 0.05g ○: Plastic waste generated is 0.05g or more but less than 0.1g △: Plastic waste generated is between 0.1g and less than 0.15g ×: Plastic waste generated is 0.15g or more It was found that the amount of plastic generated during wheel tracking tests tends to be suppressed by increasing the hydrogenation rate of the block copolymer and increasing the amount of additive. This results in finer particle size dispersion of the resin, avoiding stress concentration and thus reducing the amount of plastic generated.

[0201] [Table 5]

[0202] [Table 6]

[0203] [Table 7]

[0204] [Table 8]

[0205] Table 9

[0206] Table 10

[0207] Table 11

[0208] Table 12

[0209] Table 13

[0210] Table 14

[0211] Table 15

[0212] Table 16

[0213] Table 17

[0214] Table 18

[0215] Table 19

[0216] Table 20

[0217] Table 21

[0218] Table 22

[0219] Table 23

[0220] Table 24

[0221] Table 25

[0222] Table 26

[0223] Table 27

[0224] Table 28

[0225] Table 29

[0226] [Table 30]

[0227] [Table 31] [Industrial applicability]

[0228] The asphalt composition of the present invention has industrial potential as a material for road paving asphalt, asphalt waterproofing sheets, and the like. Furthermore, the method for producing the asphalt composition of the present invention, by adding recycled resin and crushed used tires, has industrial potential in the field of waste material recycling.

Claims

1. 85 to 99 parts by mass of asphalt, 0.1 to 15 parts by mass of block copolymer, Resin and / or rubber, 0.1 to less than 15 parts by mass, The process involves mixing the following: The block copolymer comprises a polymer block (A) mainly composed of vinyl aromatic monomer units, and a polymer block (B) containing conjugated diene monomer units and vinyl aromatic monomer units. The resin is a resin other than the block copolymer, and is an amorphous resin with a glass transition temperature of 170°C or less, or a crystalline resin with a melting point of 170°C or less. The rubber is a vulcanized product of at least one rubber selected from the group consisting of polybutadiene rubber, styrene-butadiene rubber, natural rubber, and polyisoprene rubber. As a step preceding the mixing step, The process includes kneading the block copolymer with the resin and / or rubber to produce a masterbatch. The content of the block copolymer in the masterbatch is set to 10% by mass or more and 90% by mass or less. The resin content in the masterbatch is set to be 10% by mass or more and 90% by mass or less. The rubber content in the masterbatch is set to be 10% by mass or more and 90% by mass or less. A method for producing an asphalt composition.

2. The aforementioned resin contains a polyolefin and a polar resin. A method for producing the asphalt composition according to claim 1.

3. The aforementioned resin contains 70% by mass or more of polyolefin and 30% by mass or less of polar resin. A method for producing the asphalt composition according to claim 2.

4. The aforementioned resin is the crushed material of the film. A method for producing an asphalt composition according to any one of claims 1 to 3.

5. The aforementioned film is a polyolefin single-layer film, or a multilayer film having a layer made of ethylene vinyl acetate copolymer and a layer made of polyethylene. A method for producing the asphalt composition according to claim 4.

6. The rubber is at least one selected from the group consisting of rubber powder, fine rubber powder, rubber pellets, and rubber powder as defined in JIS K6200-2019. A method for producing an asphalt composition according to any one of claims 1 to 5.

7. The aforementioned rubber is vulcanized rubber powder obtained by crushing used tires to a particle size of 5 mm or less. A method for producing an asphalt composition according to any one of claims 1 to 6.

8. In the mixing step, the mixture is heated to a temperature of 180°C or lower. A method for producing an asphalt composition according to any one of claims 1 to 7.

9. The asphalt has an asphaltene content of 15% by mass or more and 25% by mass or less, a resin content of 15% by mass or more and 30% by mass or less, and an aromatic content of 35% by mass or more and 60% by mass or less. A method for producing an asphalt composition according to any one of claims 1 to 8.

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