Manufacturing method for asphalt modifiers

Abstract

The present invention provides a method for producing an asphalt modifier that yields an asphalt composition with excellent weather resistance, and a method for producing an asphalt composition with excellent weather resistance. [Solution] A method for producing an asphalt modifier containing polyester resin and carbon black, comprising the step of subjecting an alcohol component, a carboxylic acid component, and a mixture containing a polyester compound and carbon black to a polycondensation reaction.

Description

[Technical Field]

[0001] This invention relates to a method for producing asphalt modifiers and asphalt compositions. [Background technology]

[0002] Asphalt paving is used for roads, parking lots, freight yards, and sidewalks because it is relatively easy to lay and the time from the start of paving work to the start of traffic is short. This asphalt paving uses an asphalt mixture obtained by adding aggregate to an asphalt composition (asphalt binder). Because the road surface of this asphalt pavement is formed by an asphalt mixture in which aggregate is bound with asphalt, the paved road has good hardness and durability.

[0003] For example, Patent Document 1 aims to provide an asphalt binder and asphalt mixture for road paving that can be used in a wider temperature range, while simultaneously improving the rutting resistance and crack resistance of straight asphalt, which accounts for the majority of road paving asphalt, in a simple and inexpensive manner. The invention provides a nitrogen adsorption specific surface area (N2SA) of 40 to 180 m² per 100 parts by weight of straight asphalt. 2 / g, DBP absorption amount at 80cm 3 The present invention describes an asphalt binder to which 100g or more of carbon black is added in an amount up to 30 parts by weight, characterized in that the value calculated by a predetermined formula is in the range of 200nm or less. [Prior art documents] [Patent Documents]

[0004] [Patent Document 1] Japanese Patent Publication No. 2004-256663 [Overview of the Initiative] [Problems that the invention aims to solve]

[0005] Asphalt pavement has a problem in that prolonged exposure to sunlight causes deterioration due to ultraviolet rays, leading to cracking. This problem is particularly serious in areas with strong sunlight intensity. When asphalt pavement deteriorates, repairs become necessary. Repairing the pavement increases maintenance costs and significantly impacts automobile traffic. Therefore, there is a need for asphalt pavement that is less susceptible to deterioration from ultraviolet rays and has excellent weather resistance. However, the technology described in Patent Document 1 does not consider the weather resistance of the asphalt composition. The present invention relates to a method for producing an asphalt modifier that yields an asphalt composition with excellent weather resistance, and a method for producing an asphalt composition with excellent weather resistance. [Means for solving the problem]

[0006] The inventors have found that the above problem can be solved by using a mixture containing a polyester compound and carbon black as raw materials, and by polycondensing an alcohol component, a carboxylic acid component, and a polyester compound in the presence of carbon black. In other words, the present invention encompasses the following [1] and [2]. [1] A method for producing an asphalt modifier containing polyester resin and carbon black, The process involves subjecting a mixture containing an alcohol component, a carboxylic acid component, a polyester compound, and carbon black to a polycondensation reaction. A method for manufacturing asphalt modifiers. [2] A method for producing an asphalt composition, comprising the following steps 1 and 2 in this order. Step 1: A process to obtain an asphalt modifier containing polyester resin and carbon black by subjecting an alcohol component, a carboxylic acid component, and a mixture of a polyester compound and carbon black to a polycondensation reaction. Step 2: A step of mixing asphalt with the asphalt modifier obtained in Step 1. [Effects of the Invention]

[0007] The present invention can provide a method for producing an asphalt modifier capable of obtaining an asphalt composition excellent in weather resistance and a method for producing an asphalt composition excellent in weather resistance.

Brief Description of Drawings

[0008] [Figure 1] FIG. 1 is a Raman spectrum of mixture A2 prepared in an example.

Embodiments for Carrying Out the Invention

[0009] The method for producing an asphalt modifier of the present invention is a method for producing an asphalt modifier containing a polyester resin and carbon black, and has a step of subjecting an alcohol component, a carboxylic acid component, and a mixture containing a polyester compound and carbon black to a polycondensation reaction. By mixing the asphalt modifier obtained by the method for producing an asphalt modifier of the present invention with asphalt, an asphalt composition excellent in weather resistance can be obtained.

[0010] The reason for obtaining the effects of the present invention is not clear, but it is considered as follows. Since carbon black is hardly deteriorated by ultraviolet rays, the weather resistance of roads can be improved by using it for asphalt paving. However, when carbon black is directly added and mixed with asphalt or modified asphalt, there is a problem that carbon black aggregates in the asphalt, and the amount of carbon black added tends to be very large in order to improve the weather resistance. The present invention provides a method for producing an asphalt modifier in which carbon black is uniformly dispersed in a polyester resin matrix. This is achieved by using a mixture containing a polyester compound and carbon black as raw materials, and by polycondensing an alcohol component, a carboxylic acid component, and a polyester compound in the presence of carbon black. By mixing this asphalt modifier with asphalt, the aggregation of carbon black can be suppressed, and carbon black can be uniformly dispersed in the asphalt. Furthermore, the above-mentioned asphalt modifier has ultraviolet light absorption capabilities similar to carbon black, and is less prone to molecular weight reduction of polyester resin due to ultraviolet light absorption. Therefore, the above-mentioned asphalt modifier functions as an ultraviolet light absorber that absorbs ultraviolet light in place of asphalt, and can suppress deterioration of the asphalt itself due to ultraviolet light absorption. In addition, because the above-mentioned asphalt modifier has high compatibility with asphalt, it is thought that it can be uniformly dispersed in the asphalt composition and effectively perform its function as an ultraviolet light absorber. Furthermore, the polyester resin in the above-mentioned asphalt modifier, while being compatible with the asphalt in the asphalt mixture, has polar groups that adsorb to the aggregate. This adsorption effect forms a water-resistant asphalt film on the aggregate surface, and it is believed that this film retains its water resistance even when exposed to ultraviolet radiation. In addition to these effects, the synergistic effect with uniformly dispersed carbon black is thought to greatly improve the weather resistance of the asphalt film.

[0011] The definitions of various terms used in this specification are shown below. In polyester resins, "constituent units derived from alcohol components" refers to the structure obtained by removing a hydrogen atom from the hydroxyl group of an alcohol component, and "constituent units derived from carboxylic acid components" refers to the structure obtained by removing a hydroxyl group from the carboxyl group of a carboxylic acid component. The term "carboxylic acid component" is a concept that includes not only the carboxylic acid itself, but also the anhydride that decomposes during the reaction to produce acid, and alkyl esters of carboxylic acids (for example, alkyl groups with 1 to 3 carbon atoms). When the carboxylic acid component is an alkyl ester of a carboxylic acid, the number of carbon atoms in the alkyl group, which is the alcohol residue of the ester, is not included in the number of carbon atoms of the carboxylic acid.

[0012] [Manufacturing method for asphalt modifiers] The present invention relates to a method for producing an asphalt modifier comprising a polyester resin (hereinafter also referred to as polyester 1) and carbon black, comprising the step of subjecting an alcohol component, a carboxylic acid component, and a mixture containing a polyester compound (hereinafter also referred to as polyester 2) and carbon black to a polycondensation reaction. As described later, the polyester compound is preferably polyethylene terephthalate (PET). Furthermore, all essential and optional components used in the method for producing the asphalt modifier of the present invention may be used individually or in combination of two or more.

[0013] (Alcohol content) Examples of alcohol components include alkylene oxide adducts of aromatic diols, aliphatic diols, alicyclic diols, and polyhydric alcohols of trihydric or higher hydric value. Among these, alkylene oxide adducts of aromatic diols and aliphatic diols are preferred.

[0014] The alkylene oxide adduct of an aromatic diol is preferably an alkylene oxide adduct of bisphenol A, and more preferably of formula (I):

[0015] [ka] (In the formula, OR 1 and R 2 O is an oxyalkylene group, R 1 and R 2This is an alkylene oxide adduct of 2,2-bis(4-hydroxyphenyl)propane, where each is independently an ethylene group or a propylene group, x and y represent the average number of moles of alkylene oxide added, each being a positive number, and the sum of x and y is 1 or more, preferably 1.5 or more, 16 or less, preferably 8 or less, and more preferably 4 or less.

[0016] Examples of alkylene oxide adducts of bisphenol A represented by formula (I) include propylene oxide adducts of bisphenol A and ethylene oxide adducts of bisphenol A, and from the viewpoint of weather resistance, propylene oxide adducts of bisphenol A are preferred.

[0017] Examples of aliphatic diols include ethylene glycol, 1,3-propanediol, 1,2-butanediol, 1,3-butanediol, 1,4-butanediol, 2,3-butanediol, 1,6-hexanediol, 1,8-octanediol, 1,9-nonanediol, 1,10-decanediol, 1,12-dodecanediol, 1,2-propanediol, 3-methyl-1,5-pentanediol, and neopentyl glycol, with ethylene glycol being preferred.

[0018] Examples of alicyclic diols include hydrogenated bisphenol A [2,2-bis(4-hydroxycyclohexyl)propane] and alkylene oxide adducts of hydrogenated bisphenol A with 2 to 4 carbon atoms (average number of added moles: 2 to 12).

[0019] Examples of polyhydric alcohols with a valency of 3 or higher include glycerin, pentaerythritol, trimethylolpropane, and sorbitol.

[0020] The content of alkylene oxide adducts of aromatic diols in the alcohol component is preferably 85 mol% or more, more preferably 90 mol% or more, even more preferably 95 mol% or more, and 100 mol% or less.

[0021] The alcohol component content in the total of the alcohol component, carboxylic acid component, and polyester compound contained in mixture A described later is preferably 15 mol% or more, more preferably 20 mol% or more, even more preferably 25 mol% or more, and preferably 45 mol% or less, more preferably 40 mol% or less, and even more preferably 35 mol% or less.

[0022] (Carboxylic acid component) Examples of carboxylic acid components include dicarboxylic acids and polycarboxylic acids with a valency of three or more.

[0023] Examples of dicarboxylic acids include aromatic dicarboxylic acids, aliphatic dicarboxylic acids, and alicyclic dicarboxylic acids. Among these, at least one selected from aromatic dicarboxylic acids and aliphatic dicarboxylic acids is preferred.

[0024] Examples of aromatic dicarboxylic acids include phthalic acid, isophthalic acid, and terephthalic acid. Among these, isophthalic acid and terephthalic acid are preferred, and terephthalic acid is more preferred.

[0025] The number of carbon atoms in the aliphatic dicarboxylic acid is preferably 2 or more, more preferably 3 or more, and preferably 30 or less, more preferably 20 or less. Examples of aliphatic dicarboxylic acids include oxalic acid, malonic acid, maleic acid, fumaric acid, succinic acid, citraconic acid, itaconic acid, glutaconic acid, succinic acid, adipic acid, sebacic acid, dodecanediic acid, azelaic acid, and succinic acid substituted with an aliphatic hydrocarbon group having 1 to 20 carbon atoms. Examples of succinic acid substituted with an aliphatic hydrocarbon group having 1 to 20 carbon atoms include dodecyl succinic acid, dodecenyl succinic acid, and octenyl succinic acid. Among these, succinic acid substituted with an aliphatic hydrocarbon group having 1 to 20 carbon atoms is preferred.

[0026] Examples of alicyclic dicarboxylic acids include cyclohexanedicarboxylic acid.

[0027] Preferably, the polycarboxylic acid with a valency of 3 or higher is a trivalent carboxylic acid, such as trimellitic acid.

[0028] The content of aromatic dicarboxylic acid in the carboxylic acid component is preferably 55 mol% or more, more preferably 60 mol% or more, even more preferably 65 mol% or more, and preferably 90 mol% or less, more preferably 85 mol% or less, and even more preferably 80 mol% or less.

[0029] The content of the carboxylic acid component in the total of the alcohol component, the carboxylic acid component, and the polyester compound contained in mixture A described later is preferably 10 mol% or more, more preferably 15 mol% or more, even more preferably 20 mol% or more, and preferably 45 mol% or less, more preferably 40 mol% or less, and even more preferably 35 mol% or less.

[0030] (A mixture containing polyester compounds and carbon black) A mixture containing a polyester compound (polyester 2) and carbon black (hereinafter also referred to as "mixture A") may be obtained by mixing the polyester compound and carbon black, or a mixture in which the polyester compound and carbon black are pre-mixed may be used, and it is preferable to use a mixture in which the polyester compound and carbon black are pre-mixed. Examples of mixtures containing polyester compounds and carbon black include fishing nets and discarded fishing nets, with discarded fishing nets being preferred from the viewpoint of environmental protection and resource recycling.

[0031] Polyester compounds Examples of polyester compounds include polytrimethylene terephthalate (PTT), polybutylene terephthalate (PBT), polylactic acid (PLA), and polyethylene terephthalate (PET), with polyethylene terephthalate being preferred from the viewpoint of weather resistance. PET is produced by a polycondensation reaction between an alcohol component and a carboxylic acid component, and / or by the depolymerization of a portion of PET. The resulting ethylene glycol and terephthalic acid are used as raw material monomers in the polycondensation reaction and incorporated into the polyester resin. PET is an equimolar polycondensate of ethylene glycol and terephthalic acid, and the amounts of constituent units derived from the alcohol component and the carboxylic acid component described later include constituent units derived from ethylene glycol and terephthalic acid derived from PET, respectively. PET can be manufactured by conventional methods through polycondensation of ethylene glycol with terephthalic acid, dimethyl terephthalate, etc. The PET may be new virgin PET or recycled PET. Recycled PET is obtained by collecting used PET, washing and separating it from other materials as needed, pulverizing it, depolymerizing the pulverized material to monomer units, and then resynthesizing it using these as raw materials.

[0032] Carbon Black Various grades of carbon black can be used. From the viewpoint of weather resistance, the grade of carbon black is preferably HAF, SAF, ISFA, EPC, FEF, GPF, HMF, or SRF, more preferably HAF, SAF, ISAF, or EPC, and even more preferably HAF. From the viewpoint of weather resistance, the amount of dibutyl phthalate (DBP) absorbed by carbon black is preferably 70 ml / 100g or more, more preferably 80 ml / 100g or more, even more preferably 90 ml / 100g or more, and preferably 130 ml / 100g or less, more preferably 120 ml / 100g or less, and even more preferably 110 ml / 100g or less. The DBP oil absorption capacity of carbon black is measured in accordance with ISO 4656 (JIS K 6217-4:2008) "Method for determining oil absorption capacity". From the viewpoint of weather resistance, the specific surface area of ​​nitrogen adsorption of carbon black is preferably 50 m². 2 / g or more, more comfortably 60m 2 / g or more, more preferably 70m2 / g or more, and preferably 110 m 2 / g or less, more preferably 100 m 2 / g or less, still more preferably 90 m 2 / g or less. The nitrogen adsorption specific surface area of the carbon black is measured in accordance with JIS K 6217-2:2001.

[0033] ≪Content of polyester compound in mixture A≫ From the viewpoint of weather resistance, the content of the polyester compound in mixture A is preferably 75% by mass or more, more preferably 80% by mass or more, still more preferably 85% by mass or more, and preferably 99.5% by mass or less, more preferably 99% by mass or less, still more preferably 97% by mass or less.

[0034] (Content of carbon black in mixture A) From the viewpoint of weather resistance, the content of the carbon black in mixture A is preferably 0.05% by mass or more, more preferably 1.0% by mass or more, still more preferably 3.0% by mass or more, and preferably 25.0% by mass or less, more preferably 20.0% by mass or less, still more preferably 15.0% by mass or less.

[0035] ≪Total content of polyester compound and carbon black in mixture A≫ From the viewpoint of weather resistance, the total content of the polyester compound and the carbon black in mixture A is preferably 90% by mass or more, more preferably 95% by mass or more, still more preferably 98% by mass or more, and 100% by mass or less, preferably 100% by mass.

[0036] ≪Chlorine concentration of mixture A≫ The chlorine concentration in mixture A is preferably 2000 ppm or less, more preferably 1600 ppm or less, even more preferably 1200 ppm or less, even more preferably 800 ppm or less, and even more preferably 500 ppm or less, on a mass basis, from the viewpoint of reducing the burden on the manufacturing equipment when producing the asphalt modifier. The lower the chlorine concentration in mixture A, the better, and the lower limit is, for example, 100 ppm.

[0037] (Pelletization process) As described above, in the method for producing the asphalt modifier of the present invention, it is preferable to use fishing nets or discarded fishing nets as mixture A. During the manufacturing process, carbon black is usually kneaded into PET, and the carbon black is dispersed in the PET. In the method for producing the asphalt modifier of the present invention, from the viewpoint of weather resistance, it is preferable to melt the fishing nets or discarded fishing nets before subjecting them to the polycondensation reaction and use them as mixture A. By melting the fishing nets or discarded fishing nets, the carbon black can be dispersed more uniformly in the PET, and the weather resistance of the asphalt composition can be further improved. Before melting the fishing net or discarded fishing net, it may be crushed or broken as needed. It may also be kneaded during melting. Before melting and kneading, the fishing net or discarded fishing net may be crushed or broken, and then washed with water to remove any attached salt. Washing with water can reduce the chlorine concentration of the resulting mixture A. Although this chlorine concentration does not directly affect weather resistance, it is preferable to reduce the chlorine concentration as much as possible from the viewpoint of preventing pitting corrosion of the stainless steel reaction tank used in the polycondensation reaction by chloride ions and allowing the stainless steel reaction tank to be used repeatedly. The attached salt may be washed off by rainwater in the open, or further washed with running water to reduce the chlorine concentration, or rinsed in a drum-type washing machine after crushing or breaking the fishing net. Examples of equipment used for melt kneading include single-screw extruders, twin-screw extruders, kneaders, Banbury mixers, mixing roll mills, open roll mills, and grash mixers. The temperature during melt kneading is, for example, 230°C to 300°C, preferably 250°C to 290°C. For example, after melting and kneading in an extruder, the strand-like molten material is extruded from a die, cooled with water, and then pelletized using a cutter device to obtain pelletized mixture A. In this specification, the process of melting fishing nets or discarded fishing nets and then pelletizing them is also referred to as repelletization. Pellet shapes include granular or cylindrical forms measuring 3-5 mm.

[0038] The amount of polyester compound in the total of the alcohol component, the carboxylic acid component, and the polyester compound contained in mixture A described later is preferably 30 mol% or more, more preferably 35 mol% or more, even more preferably 40 mol% or more, and preferably 60 mol% or less, more preferably 55 mol% or less, and even more preferably 50 mol% or less. In other words, the amount of mixture A used is such that the amount of polyester compound in the total of the alcohol component, the carboxylic acid component, and the polyester compound contained in mixture A described later falls within the above preferred range.

[0039] (Polycondensation reaction) In the method for producing the asphalt modifier of the present invention, the above-mentioned alcohol component, carboxylic acid component, and mixture A are subjected to a polycondensation reaction; that is, the alcohol component, carboxylic acid component, and polyester compound are polycondensed in the presence of carbon black. The polycondensation reaction can be carried out, for example, in an inert gas atmosphere, in the presence of an esterification catalyst, esterification co-catalyst, polymerization inhibitor, etc., as needed, at a temperature of approximately 120°C to 250°C until the desired softening point is reached. Examples of esterification catalysts include tin compounds such as dibutyltin oxide and di(2-ethylhexanoate)tin(II), and titanium compounds such as titanium diisopropoxybis(triethanolamine). Examples of esterification co-catalysts that can be used together with the esterification catalyst include gallic acid (3,4,5-trihydroxybenzoic acid). The amount of esterification catalyst used is preferably 0.01 parts by mass or more and 10 parts by mass or less, based on 100 parts by mass of the total amount of the alcohol component, carboxylic acid component, and mixture A. The amount of esterification co-catalyst used is preferably 0.001 parts by mass or more and 1 part by mass or less, based on 100 parts by mass of the total amount of the alcohol component, carboxylic acid component, and mixture A. Examples of polymerization inhibitors include radical polymerization inhibitors such as 4-tert-butylcatechol. When a polymerization inhibitor is used, the amount of polymerization inhibitor used is preferably 0.001 parts by mass or more and 1 part by mass or less, based on 100 parts by mass of the total amount of the alcohol component, carboxylic acid component, and mixture A.

[0040] <Polyester resin> The following describes the preferred content of each component-derived structural unit in the resulting polyester resin.

[0041] The content of constituent units derived from the alkylene oxide adduct of bisphenol A is preferably 25 mol% or more, more preferably 30 mol% or more, even more preferably 35 mol% or more, and preferably 55 mol% or less, more preferably 50 mol% or less, and even more preferably 45 mol% or less, compared to the constituent units derived from the alcohol component.

[0042] The amount of constituent units derived from aliphatic diols is preferably 35 mol% or more, more preferably 45 mol% or more, even more preferably 55 mol% or more, and preferably 75 mol% or less, more preferably 70 mol% or less, and even more preferably 65 mol% or less, compared to the constituent units derived from alcohol components.

[0043] The amount of polyester-derived aliphatic diol constituent units is preferably 90 mol% or more, more preferably 95 mol% or more, even more preferably 98 mol% or more, and 100 mol% or less, and preferably 100 mol%, out of the total constituent units derived from aliphatic diols. Furthermore, the constituent units derived from alcohol components shall include constituent units derived from diols derived from polyester.

[0044] The amount of ethylene glycol constituent units derived from PET is preferably 90 mol% or more, more preferably 95 mol% or more, even more preferably 98 mol% or more, and 100 mol% or less, and preferably 100 mol%, compared to the constituent units derived from aliphatic diols.

[0045] The amount of constituent units derived from aromatic dicarboxylic acids is preferably 75 mol% or more, more preferably 80 mol% or more, even more preferably 85 mol% or more, and preferably 97 mol% or less, more preferably 95 mol% or less, and even more preferably 93 mol% or less, out of the constituent units derived from carboxylic acid components.

[0046] The amount of aromatic dicarboxylic acid constituent units derived from the polyester compound is preferably 55 mol% or more, more preferably 60 mol% or more, even more preferably 65 mol% or more, and preferably 85 mol% or less, more preferably 80 mol% or less, and even more preferably 75 mol% or less, out of the constituent units derived from the aromatic dicarboxylic acid. Furthermore, the constituent units derived from carboxylic acid components shall include constituent units derived from dicarboxylic acids derived from polyester compounds.

[0047] The amount of terephthalic acid constituent units derived from PET is preferably 55 mol% or more, more preferably 60 mol% or more, even more preferably 65 mol% or more, and preferably 85 mol% or less, more preferably 80 mol% or less, and even more preferably 75 mol% or less, compared to the constituent units derived from aromatic dicarboxylic acid.

[0048] If the carboxylic acid component includes an aliphatic dicarboxylic acid, the amount of the aliphatic dicarboxylic acid is preferably 3 mol% or more, more preferably 5 mol% or more, even more preferably 7 mol% or more, and preferably 25 mol% or less, more preferably 20 mol% or less, and even more preferably 15 mol% or less, in the carboxylic acid component.

[0049] In the raw materials for the polyester resin (polyester 1), the molar equivalent ratio (COOH group / OH group) of the carboxyl group (COOH group) of the carboxylic acid component to the hydroxyl group (OH group) of the alcohol component is preferably 0.7 or higher, more preferably 0.8 or higher, and preferably 1.3 or lower, more preferably 1.2 or lower. Furthermore, the "molar equivalent ratio (COOH group / OH group) value" shall be calculated assuming that the alcohol component contains the same amount of alcohol component as the constituent units derived from the polyester compound, and the carboxylic acid component contains the same amount of carboxylic acid component as the constituent units derived from the polyester compound.

[0050] (Physical properties of polyester resin) From the viewpoint of weather resistance, the softening point of the polyester resin is preferably 80°C or higher, more preferably 85°C or higher, even more preferably 95°C or higher, and preferably 140°C or lower, more preferably 130°C or lower, even more preferably 120°C or lower, and even more preferably 115°C or lower. From the viewpoint of weather resistance, the glass transition temperature of the polyester resin is preferably 30°C or higher, more preferably 40°C or higher, even more preferably 50°C or higher, and preferably 95°C or lower, more preferably 80°C or lower, even more preferably 70°C or lower, and even more preferably 65°C or lower.

[0051] The softening point and glass transition point of the polyester resin can be appropriately adjusted depending on the type and amount of raw materials used, as well as manufacturing conditions such as reaction temperature, reaction time, and cooling rate. These values ​​can be determined by the method described in the examples. Furthermore, when using two or more types of polyester resins in combination, it is preferable that the softening point and glass transition point of the resulting mixture are within the above-mentioned ranges.

[0052] The asphalt modifier obtained by the method for producing asphalt modifiers of the present invention can be used, for example, by mixing it with asphalt to obtain an asphalt composition. After adding heated aggregate to the obtained asphalt composition to make an asphalt mixture, it can be used for paving. The asphalt modifier obtained by the method for producing asphalt modifiers of the present invention can be suitably used as an asphalt modifier for blending into an asphalt mixture containing aggregate.

[0053] [Method for producing asphalt composition] The method for producing the asphalt composition of the present invention comprises the following steps 1 and 2 in this order. Step 1: A process to obtain an asphalt modifier containing polyester resin and carbon black by subjecting an alcohol component, a carboxylic acid component, and a mixture of a polyester compound and carbon black to a polycondensation reaction. Step 2: A step of mixing asphalt with the asphalt modifier obtained in Step 1.

[0054] Step 1 is the same as the [method for manufacturing asphalt modifier] described above. In step 2, for example, asphalt is heated and melted, an asphalt modifier is added, and the mixture is stirred and mixed in a commonly used mixer until the asphalt modifier is uniformly dispersed in the asphalt, thereby obtaining an asphalt composition. Commonly used mixers include homomixers, dissolvers, paddle mixers, ribbon mixers, screw mixers, planetary mixers, vacuum backflow mixers, roll mills, and twin-screw extruders.

[0055] The mixing temperature of the asphalt and the asphalt modifier is preferably 140°C or higher, more preferably 150°C or higher, even more preferably 160°C or higher, and preferably 230°C or lower, more preferably 210°C or lower, and even more preferably 200°C or lower, from the viewpoint of uniformly dispersing the asphalt modifier in the asphalt. Furthermore, the mixing time between the asphalt and the asphalt modifier is preferably 5 minutes or more, more preferably 10 minutes or more, even more preferably 20 minutes or more, and preferably 5 hours or less, more preferably 3 hours or less, and even more preferably 1 hour or less, from the viewpoint of uniformly dispersing the asphalt modifier in the asphalt. The asphalt composition obtained by the method for producing the asphalt composition of the present invention is a binder composition, and for example, aggregate can be added to the asphalt composition to make an asphalt mixture which can then be used for paving. In other words, the asphalt composition obtained by the method for producing the asphalt composition of the present invention is suitable for paving, and is particularly suitable for road paving.

[0056] <Asphalt> Various types of asphalt can be used. For example, in addition to straight asphalt, which is petroleum asphalt used for paving, modified asphalt can also be used. Straight asphalt refers to the residual bituminous substance obtained by subjecting crude oil to atmospheric distillation, vacuum distillation, etc. Modified asphalts include blown asphalt and polymer-modified asphalt (hereinafter also referred to as "polymer-modified asphalt") which is modified with polymer materials such as thermoplastic elastomers and thermoplastic resins. Blown asphalt refers to asphalt obtained by heating a mixture of straight asphalt and heavy oil, and then blowing air into it to oxidize it. The asphalt is preferably selected from straight asphalt and polymer-modified asphalt, with polymer-modified asphalt being more preferred from the viewpoint of durability of the asphalt pavement, and straight asphalt being more preferred from the viewpoint of versatility.

[0057] (Thermoplastic elastomer) Examples of thermoplastic elastomers used in polymer-modified asphalt include at least one selected from styrene / butadiene block copolymer (hereinafter also referred to as "SB"), styrene / butadiene / styrene block copolymer (hereinafter also referred to as "SBS"), styrene / butadiene random copolymer (hereinafter also referred to as "SBR"), styrene / isoprene block copolymer (hereinafter also referred to as "SI"), styrene / isoprene / styrene block copolymer (hereinafter also referred to as "SIS"), styrene / isoprene random copolymer (hereinafter also referred to as "SIR"), ethylene / vinyl acetate copolymer, ethylene / acrylic acid ester copolymer, styrene / ethylene / butylene / styrene copolymer, styrene / ethylene / propylene / styrene copolymer, polyurethane thermoplastic elastomer, polyolefin thermoplastic elastomer, isobutylene / isoprene copolymer, polyisoprene, polychloroprene, synthetic rubber other than those listed above, and natural rubber.

[0058] Among these, the thermoplastic elastomer is preferably at least one selected from SB, SBS, SBR, SI, SIS, SIR, and ethylene / acrylic acid ester copolymer, more preferably at least one selected from SB, SBS, SBR, SI, SIS, and SIR, even more preferably at least one selected from SBR and SBS, and even more preferably SBS. From the viewpoint of durability of asphalt pavement, the content of thermoplastic elastomer in polymer-modified asphalt is preferably 0.1% by mass or more, more preferably 0.5% by mass or more, even more preferably 1% by mass or more, and preferably 30% by mass or less, more preferably 15% by mass or less, and even more preferably 7% by mass or less.

[0059] The amount of asphalt used in step 2 is preferably 0.5 parts by mass or more, more preferably 1 part by mass or more, even more preferably 3 parts by mass or more, and preferably 15 parts by mass or less, more preferably 10 parts by mass or less, and even more preferably 7 parts by mass or less, per 100 parts by mass of asphalt, from the viewpoint of weather resistance.

[0060] <Dispersant> In step 2, the asphalt, the asphalt modifier obtained in step 1, and the dispersant may be mixed together. Examples of dispersants include polymeric dispersants such as polyamidoamines and their salts, polycarboxylic acids and their salts, high molecular weight unsaturated acid esters, modified polyurethanes, modified polyesters, modified poly(meth)acrylates, (meth)acrylic copolymers, and naphthalene sulfonic acid formalin condensates. In this invention, "polymeric dispersant" refers to a dispersant with a weight-average molecular weight of 1,000 or more. However, from the viewpoint of storage stability, the amount of dispersant used is preferably less than 1 part by mass, more preferably less than 0.5 parts by mass, per 100 parts by mass of asphalt modifier, and even more preferably substantially omits it.

[0061] The asphalt composition of the present invention, from the viewpoint of weather resistance, is exposed to ultraviolet light in the 300-400 nm range at 150 W / m². 2 Then, under the conditions described in the examples, the carbonyl index (C) after irradiation was calculated. A ) and the carbonyl index (C) before UV irradiation B It is preferable that ) satisfies the following formula (1). C A / C B <3.5 (1) The carbonyl index is measured by Fourier transform infrared spectroscopy (FT-IR) at 1600 cm² of the asphalt composition. -1 Absorbance at 1700 cm -1 Ratio of absorbance (1700cm²) -1 Absorbance / 1600cm -1 This is the absorbance. From the viewpoint of weather resistance, the upper limit of formula (1) is preferably 3.0 or less. The lower limit is, for example, 1.0 from a manufacturing viewpoint.

[0062] The asphalt composition of the present invention, from the viewpoint of weather resistance, is exposed to ultraviolet light in the 300-400 nm range at 150 W / m². 2Then, the butadiene index (B) after irradiation under the conditions described in the example is A ) and the butadiene index (B) before UV irradiation B It is preferable that ) satisfies the following equation (2). 0.7 ≤ B A / B B (2) The butadiene index is measured by Fourier transform infrared spectroscopy (FT-IR) at 1600 cm² of the asphalt composition. -1 965 cm² relative to absorbance -1 The ratio of absorbances (965cm²) -1 Absorbance / 1600cm -1 This is the absorbance. From the viewpoint of weather resistance, the upper limit of formula (2) is preferably 1.0 or less.

[0063] [Asphalt mixture] This section describes asphalt mixtures, which are a suitable example of the use of asphalt compositions. The asphalt mixture comprises aggregate and the above-mentioned asphalt composition. In other words, the asphalt mixture comprises at least aggregate, asphalt, polyester resin, and carbon black.

[0064] <Aggregates> As aggregate, for example, crushed stone, pebbles, gravel, sand, recycled aggregate, ceramics, etc., can be arbitrarily selected and used. Furthermore, as aggregate, either coarse aggregate with a particle size of 2.36 mm or more or fine aggregate with a particle size of less than 2.36 mm can be used, and a combination of coarse and fine aggregate is preferred. From the viewpoint of durability of asphalt pavement, the aggregate content in the asphalt mixture is preferably 85% by mass or more, more preferably 90% by mass or more, more preferably 92% by mass or more, and preferably 98% by mass or less, more preferably 97% by mass or less, and even more preferably 96% by mass or less.

[0065] <Additives> In addition to the aggregate, asphalt, polyester resin, and carbon black mentioned above, the asphalt mixture may also contain, if necessary, various additives conventionally used in asphalt mixtures, such as film-forming agents, thickening and stabilizing agents, and emulsifiers. The total content of these additives is preferably 50% by mass or less, more preferably 25% by mass or less, and even more preferably 5% by mass or less in the asphalt mixture.

[0066] [Method for producing asphalt mixture] There are no particular restrictions on the method for producing the asphalt mixture, and it may be produced by any method. Generally, it can be produced in accordance with the method for producing an asphalt mixture containing aggregate and asphalt. Specifically, one method involves adding and mixing the above-mentioned asphalt composition with heated aggregate.

[0067] From the viewpoint of durability of the asphalt pavement, the temperature of the heated aggregate is preferably 130°C or higher, more preferably 150°C or higher, and even more preferably 170°C or higher. From the viewpoint of preventing thermal degradation of the asphalt, it is preferably 230°C or lower, more preferably 210°C or lower, and even more preferably 200°C or lower.

[0068] The mixing temperature of the aggregate and the asphalt composition is preferably 130°C or higher, more preferably 150°C or higher, and even more preferably 170°C or higher, from the viewpoint of durability of the asphalt pavement, and preferably 230°C or lower, more preferably 210°C or lower, and even more preferably 200°C or lower, from the viewpoint of preventing thermal degradation of the asphalt. The mixing time between the aggregate and the asphalt composition is not particularly limited, but is preferably 30 seconds to 2 hours, more preferably 1 minute or more, even more preferably 2 minutes or more, and more preferably 1 hour or less, and even more preferably 30 minutes or less.

[0069] From the viewpoint of the durability of the asphalt pavement, the method for producing the asphalt mixture preferably includes a step of mixing the aggregate and the asphalt composition, and then holding the resulting asphalt mixture at the above-mentioned mixing temperature or a temperature higher than the mixing temperature. In the process of holding the asphalt mixture, the mixture may be further mixed. The holding time is preferably 0.5 hours or more, more preferably 1 hour or more, and even more preferably 1.5 hours or more. The upper limit of the time is not particularly limited, but is, for example, about 48 hours.

[0070] [Road paving methods] Asphalt mixtures are suitable for road paving, and as described above, asphalt mixtures obtained by adding aggregate to an asphalt composition are used for road paving. The road paving method includes the step of applying the aforementioned asphalt mixture to the road to form an asphalt paving material layer. Specifically, the road paving method includes the step of mixing the aforementioned asphalt composition with heated aggregate to obtain an asphalt mixture (step I), and the step of applying the asphalt mixture obtained in step I to the road to form an asphalt paving material layer (step II). The asphalt paving material layer is preferably a base layer or a surface layer.

[0071] The asphalt mixture can be compacted using a known construction machinery setup and a similar method. When used as a heated asphalt mixture, the compaction temperature is preferably 100°C or higher, more preferably 120°C or higher, even more preferably 130°C or higher, and preferably 200°C or lower, more preferably 180°C or lower, from the viewpoint of durability of the asphalt pavement. [Examples]

[0072] The present invention will be specifically described below with reference to examples, but the present invention is not limited in any way by these examples.

[0073] [Measurement method] [Raman spectroscopy measurement of mixture A] The Raman spectrum of mixture A was measured using a laser Raman microscope (RAMANplus, manufactured by Nanophoton Inc.) under the following conditions. The peak originating from carbon black was at 1,350 cm⁻¹. -1 and 1,580cm -1 It is observed in this way. (Measurement conditions) Laser wavelength: 785nm Laser intensity: 1mW Exposure time: 40s Magnification: x 100(LU Plan Flior) Center wavelength: 1450cm -1 Grating: 600gr / mm

[0074] [Carbon black (CB) content in mixture A] Approximately 15g of pelletized mixture A was placed in a porcelain crucible and placed in an electric furnace under a nitrogen atmosphere. The heating pattern was 200°C / hr from room temperature (25°C) to 200°C, 25°C / hr from 200°C to 400°C, and 200°C / hr from 400°C to 800°C. Heating was stopped immediately after reaching 800°C, and the porcelain crucible was left to stand in the furnace until it cooled to room temperature before being removed. The ash content was taken from the porcelain crucible, its mass was measured, and the amount was divided by the mass of mixture A before heating and multiplied by 100 to obtain the residual charcoal amount A (mass%). Furthermore, when the amount of residual carbon in PET (UK-31, manufactured by Utsumi Co., Ltd.) was determined using the same method, the amount of residual carbon when PET was 100% by mass was 19% by mass. It was assumed that the amount of residual carbon derived from PET in mixture A obtained by heating under the same conditions as above was 19% by mass. In the case of CB only, the amount of residual carbon is 100% by mass, so the amount of CB in the unheated mixture A pellet consisting of PET and CB was set to x (mass%), and the amount of PET was set to "100-x" (mass%), and x (mass%) was calculated from the following formula. (100-x)*19 / 100+x=Remaining coal amount A

[0075] [Measurement of chlorine concentration in mixture A] The sample was reacted with sodium butyrate under specified conditions, and the resulting chloride ions were quantified using silver nitrate. The chlorine concentration of mixture A was expressed as a mass percentage relative to the sample. The chlorine concentration was measured by the following method. A sample was prepared by pulverizing a pellet of mixture A using a freeze-milling machine. The sample was measured and placed in a 200 mL Erlenmeyer flask with a stopper. 25 mL of sodium 1-butanol solution (concentration 20 g / L) was added to the Erlenmeyer flask to dissolve the sample. A cooling tube was attached, and the mixture was gently boiled on a hot plate for 1.5 hours. The Erlenmeyer flask was allowed to stand at room temperature, and the sample was dissolved by adding it while washing the cooling tube with alcohol or water. 15 mL of 25% by mass nitric acid solution was then added. Next, the mixture was titrated with 0.1 mol / L silver nitrate solution using a potentiometric titrator. A blank test was also performed in parallel. Chlorine concentration (mass%) = (AB) × M × f × 35.46 × 100 / Sample volume (g) / 1000 A = Titration volume of sample (mL) B = Titration volume of blank test (mL) M = Molar concentration of silver nitrate standard solution (mol / L) f = Factor of silver nitrate standard solution 35.36 Molecular weight of chlorine

[0076] [Softening point and glass transition point of polyester resin] (1) Softening point Using a flow tester "CFT-500D" (manufactured by Shimadzu Corporation), 1 g of sample was heated at a heating rate of 6°C / min while a load of 1.96 MPa was applied by a plunger and extruded from a nozzle with a diameter of 1 mm and a length of 1 mm. The amount of plunger descent of the flow tester was plotted against temperature, and the temperature at which half of the sample flowed out was defined as the softening point. (2) Glass transition temperature Using a differential scanning calorimeter "Q-100" (manufactured by T.A. Instruments Japan Co., Ltd.), 0.01 to 0.02 g of the sample was weighed into an aluminum pan, heated to 200°C, and then cooled to 0°C at a rate of 10°C / min. Next, measurements were taken while heating to 150°C at a rate of 10°C / min. The glass transition point was defined as the temperature at the intersection of the extension of the baseline below the maximum endothermic peak temperature and the tangent line representing the maximum slope from the peak's rising portion to its peak.

[0077] [Manufacturing of asphalt modifiers] Example M1 (Manufacturing of asphalt modifier 1) Used fishing nets (manufactured by Kinoshita Seimo Co., Ltd.) were crushed, washed with running water, and then dried in a 180°C dryer to remove moisture. Subsequently, strands were prepared using a twin-screw mixer (TEX28V, manufactured by Japan Steel Works, screw diameter 28 mm) at a mixing temperature of 270°C and a feed rate of 5 kg / h. These strands were then cut and pelletized (pellet diameter 3 mm). Raman spectroscopy of mixture A1 (a mixture of PET and carbon black) confirmed that mixture A1 contained carbon black (CB). Table 1 shows the manufacturing process and chlorine concentration of mixture A1. The BPA-PO shown in Table 2 was placed in a 5-liter four-necked flask equipped with a thermometer, stainless steel stirring rod, a fall-flow condenser, and a nitrogen inlet tube, and heated to 100°C. Terephthalic acid and mixture A1 were added at 100°C, and the temperature was increased to 235°C at a rate of 0.5°C / min. Under a nitrogen atmosphere at 235°C, 20 g of tin(II) di(2-ethylhexanoate) and 2 g of gallic acid were added, and the polycondensation reaction was carried out at 235°C for 6 hours. After cooling to 180°C, dodecenyl succinic anhydride was added. The temperature was increased from 180°C to 220°C at a rate of 0.3°C / min, and the reaction was carried out at 220°C and 20 kPa until the softening point shown in Table 2 was reached, yielding asphalt modifier 1.

[0078] Example M2 (Manufacturing of Asphalt Modifier 2) Instead of using used fishing nets manufactured by Kinoshita Seimo Co., Ltd., used fishing nets (manufactured by Nitto Seimo Co., Ltd.) were used to obtain mixture A2 (a mixture of pellets, PET, and carbon black) in the same manner as mixture A1. Asphalt modifier 2 was obtained in the same manner as in Example M1, except that mixture A2 was used instead of mixture A1. Furthermore, Raman spectroscopy confirmed that mixture A2 contains CB. The obtained Raman spectrum is shown in Figure 1. The vertical axis represents scattering intensity, and the horizontal axis represents Raman shift (cm).-1 )

[0079] Example M3 (Manufacturing of asphalt modifier 3) Asphalt modifier 3 was obtained in the same manner as in Example M1, except that used fishing nets (manufactured by Nichimo Co., Ltd.) were used instead of used fishing nets manufactured by Kinoshita Seimo Co., Ltd., and mixture A3 (a mixture of pellets, PET, and carbon black) was obtained in the same manner as mixture A1, and used instead of mixture A1.

[0080] Example M4 (Manufacturing of asphalt modifier 4) Used fishing nets (manufactured by Teijin Limited) were cut up and used as mixture A4. Asphalt modifier 4 was obtained in the same manner as in Example M1, except that mixture A4 was used instead of mixture A1.

[0081] Comparative Example M1 (Manufacturing of asphalt modifier c1) Asphalt modifier c1 (polyester resin) was obtained in the same manner as in Example M1, except that PET (UK-31 manufactured by Utsumi Co., Ltd.) was used instead of mixture A1.

[0082] Comparative Example M2 (Manufacturing of asphalt modifier c2) A baby roll heated to 180°C was rotated, and 99g of polyester resin synthesized in Comparative Example M1 and 2g of carbon black (HAF) were placed on it to dissolve the polyester resin. The rotation speed was changed to 15 rpm, and the mixture was kneaded for 20 minutes. After kneading was complete, the mixture was removed from the kneader, the mixture adhering to the baby roll was scraped off, and the scraped mixture was kneaded into the mixture removed from the kneader to obtain asphalt modifier c2.

[0083] [Table 1]

[0084] [Table 2]

[0085] [Manufacturing of asphalt composition] Example 1 (Production of Asphalt Composition 1) 50 g of polymer-modified asphalt modifier type II (HR binder, manufactured by Toa Road Industry Co., Ltd.) was weighed into a 300 mL stainless steel container and stirred at 300 rpm with a propeller while being heated to 180 °C. After stirring for 10 minutes, 2.5 g of asphalt modifier 1 was added and stirred for 30 minutes under the same conditions to obtain asphalt composition 1. One to two drops of the above-mentioned asphalt composition 1 were placed on a microscope slide, a cover glass was placed over it, and the slide was left standing in a 180°C drying oven for 3 minutes. After confirming that the asphalt composition 1 sandwiched between the microscope slide and the cover glass had spread and an asphalt film had formed on the microscope slide, the cover glass was immediately removed.

[0086] Examples 2-4 and Comparative Examples 1 and 2 (Production of asphalt compositions 2-4, c1, and c2) Except for using the types of asphalt modifiers shown in Table 3, asphalt compositions 2-4, c1, and c2 were prepared in the same manner as in Example 1, and asphalt coatings were formed on glass slides using each asphalt composition.

[0087] Comparative Example 3 50 g of polymer-modified asphalt type II (HR binder, manufactured by Toa Road Industry Co., Ltd.) was weighed into a 300 mL stainless steel container and stirred at 300 rpm with a propeller while being heated to 180 °C. An asphalt coating was formed in the same manner as in Example 1, except that polymer-modified asphalt type II was used after stirring for 30 minutes.

[0088] [evaluation] The asphalt composition or the asphalt coating obtained from asphalt was evaluated as follows. The results are shown in Table 3.

[0089] [Weather resistance test] The asphalt coatings on the glass slides obtained in each example and comparative example were subjected to UV intensity testing at 150 W / m² using a Super Xenon Weather Meter SX75 (Suga Test Instruments Co., Ltd.). 2 Ultraviolet irradiation was performed at an irradiation wavelength of 300-400 nm. Within a 1-hour cycle, the first 9 minutes were conducted under rainfall conditions (rain spray pressure: 0.1 MPa (0.48 L / min)) and a chamber temperature of 28°C. Subsequently, ultraviolet irradiation was performed for 51 minutes under conditions of a chamber temperature of 40°C and relative humidity of 75%. To ensure uniform ultraviolet irradiation, the aforementioned glass slides were attached around the lamp and irradiated with ultraviolet light for 4 hours (4 cycles) while rotating. This was used as the post-ultraviolet irradiation sample. For the measurements in (1) and (2) below, samples before and after UV irradiation were used.

[0090] (1) Pencil hardness measurement Pencil hardness was determined using a pencil scratch tester (manufactured by TP Giken Co., Ltd.) in accordance with JIS K5600-5-4:1990. The asphalt coating formed on a glass slide was scratched with pencils of progressively lower hardness, starting from a high-hardness 9H. The scratches on the asphalt coating were observed using a microscope (Olympus DSX1000), and the pencil hardness at which the coating was scratched and the glass was exposed was determined. The highest pencil hardness at which the coating was not scratched and the glass was not exposed was defined as the pencil hardness of the asphalt coating. For example, if the glass was exposed at 4H but not at 3H, the pencil hardness of the asphalt coating was defined as 3H.

[0091] (2) FT-IR measurement (calculation of carbonyl index increment) FT-IR measurements were performed using equipment manufactured by Thermo Fisher Scientific Co., Ltd. Measurements were taken using samples before and after UV irradiation, and the carbonyl indices (I) and (II) below were calculated from the obtained absorption peak curves. The increment of the carbonyl index was then calculated using the following formula. A larger increment in the carbonyl index indicates deterioration of the asphalt coating, while a smaller increment indicates superior weather resistance. Furthermore, the butadiene indices (III) and (IV) below were calculated from the absorption peak curve, and the decrease in the butadiene index in the styrene-butadiene-styrene copolymer (SBS) was calculated using the following formula. A larger decrease in the butadiene index indicates that the butadiene in the SBS contained in the asphalt is being cleaved, and a smaller decrease in the butadiene index indicates superior weather resistance. Increment of carbonyl index = Carbonyl index (II) / Carbonyl index (I) Carbonyl Index (II): 1700 cm³ of the sample after UV irradiation. -1 Absorbance / 1600cm -1 absorbance Carbonyl Index (I): 1700 cm³ of the sample before UV irradiation. -1 Absorbance / 1600cm -1 absorbance Decrease in the butadiene index = Butadiene index (IV) / Butadiene index (III) Butadiene Index (IV): 965 cm³ of the sample after UV irradiation. -1 Absorbance / 1600cm -1 absorbance Butadiene Index (III): 965 cm³ of the sample before UV irradiation -1 Absorbance / 1600cm -1 absorbance

[0092] [Table 3]

[0093] As is clear from Table 3, the asphalt composition obtained by mixing the asphalt modifier obtained by the method for producing the asphalt modifier of the present invention with asphalt, that is, the asphalt coating produced using the asphalt composition obtained by the method for producing the asphalt composition of the present invention, has a pencil hardness of B or higher even after ultraviolet irradiation, and shows little increase in carbonyl index and little decrease in butadiene index, indicating excellent weather resistance (Examples 1-4). In contrast, the asphalt coating produced using an asphalt composition manufactured without carbon black (Comparative Example 1), and the asphalt coating produced using an asphalt composition obtained through a process of mixing polyester resin and carbon black (Comparative Example 2), had a pencil hardness of 3B or less after UV irradiation and showed a large decrease in the butadiene index, indicating poor weather resistance. Furthermore, the asphalt coating produced using polymer-modified asphalt type II (Comparative Example 3) had a pencil hardness of 8B after UV irradiation, showed a large increase in the carbonyl index and a large decrease in the butadiene index, indicating poor weather resistance.

Claims

1. A method for producing an asphalt modifier containing polyester resin and carbon black, The process involves subjecting a mixture containing an alcohol component, a carboxylic acid component, a polyester compound, and carbon black to a polycondensation reaction. A method for manufacturing asphalt modifiers.

2. A method for producing an asphalt modifier according to claim 1, wherein the polyester compound is polyethylene terephthalate.

3. A method for producing an asphalt modifier according to claim 2, comprising the step of melting fishing nets or discarded fishing nets to obtain a mixture of polyethylene terephthalate and carbon black.

4. A method for producing an asphalt modifier according to any one of claims 1 to 3, wherein the carbon black content is 1.0% by mass or more and 15.0% by mass or less of the total amount of polyester compound and carbon black contained in the mixture.

5. A method for producing an asphalt composition, comprising the following steps 1 and 2 in this order. Step 1: A process to obtain an asphalt modifier containing polyester resin and carbon black by subjecting an alcohol component, a carboxylic acid component, and a mixture of a polyester compound and carbon black to a polycondensation reaction. Step 2: A step of mixing asphalt with the asphalt modifier obtained in Step 1.

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