Asphalt modifier

Abstract

The present invention relates to an asphalt modifier that includes a resin A and carbon black, the carbon black content being no more than 2.5 mass%, and the mass ratio (inorganic filler / carbon black) of inorganic filler (excluding carbon black) to carbon black being no more than 1.

Description

Asphalt modifier

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

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

[0003] For example, Patent Document 1 (JP 2004-256663 A) describes a method for improving the rut resistance and crack resistance of straight asphalt, which accounts for the majority of asphalt used in road paving, and for providing an asphalt binder and asphalt mixture for paving that can be used in a wider temperature range, simply and inexpensively, by calculating the nitrogen adsorption specific surface area (N ２ SA) is 40 to 180m ２ / g, DBP absorption is 80 cm ３ The asphalt binder described in the publication is characterized in that the asphalt binder contains up to 30 parts by weight of carbon black in an amount of 100 g or more, and that the A value calculated by the following formula (1) is in the range of 200 nm or less: A = f Dst {(0.86) / (φ β) １／３ )-1} (1) where f=exp(ΔD50 / 2Dst) ２ β = [1 + 0.0181 (24M4DBP)] / 1.59. Dst is the mode diameter (nm) of the Stokes equivalent diameter distribution of carbon black aggregates, ΔD50 is the half-width (nm) of the Stokes equivalent diameter distribution, φ is the volume fraction, and 24M4DBP is the compressed DBP absorption (cm ３ / 100g).

[0004] [1] An asphalt modifier comprising resin A and carbon black, wherein the carbon black content is 2.5% by mass or less, and the mass ratio of the inorganic filler (excluding carbon black) to the carbon black [inorganic filler / carbon black] is 1 or less. [2] An asphalt composition containing asphalt and the asphalt modifier described in [1] above. [3] A method for producing an asphalt composition, comprising the following steps 1 to 3, in this order: Step 1: Mixing resin A and carbon black to obtain an asphalt modifier; Step 2: Mixing asphalt with the asphalt modifier obtained in step 1, provided that the carbon black content in the asphalt modifier obtained in step 1 is 2.5% by mass or less, and the mass ratio of the inorganic filler (excluding carbon black) to the carbon black [inorganic filler / carbon black] is 1 or less. Detailed Description of the Invention

[0005] Asphalt pavement has a problem in that when exposed to sunlight for a long period of time, ultraviolet rays cause deterioration and cracks. This problem is particularly serious in areas with strong sunlight irradiation intensity. When asphalt pavement deteriorates, repair becomes necessary. Pavement repair increases maintenance costs and has a significant impact on automobile traffic. Therefore, there is a demand for asphalt pavement that is less susceptible to deterioration by 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 an asphalt modifier that can realize an asphalt composition with excellent weather resistance, an asphalt composition using the asphalt modifier, and a method for producing the asphalt composition.

[0006] The present inventors have discovered that the above-mentioned problems can be solved by blending a specific amount or less of carbon black in an asphalt modifier containing Resin A and carbon black.

[0007] The present invention can provide an asphalt modifier that can realize an asphalt composition with excellent weather resistance, an asphalt composition using the asphalt modifier, and a method for producing the asphalt composition.

[0008] [Asphalt modifier] The asphalt modifier of the present invention contains resin A and carbon black, has a carbon black content of 2.5 mass% or less, and has a mass ratio of inorganic filler (excluding carbon black) to carbon black [inorganic filler / carbon black] of 1 or less. From the viewpoint of uniformly dispersing the carbon black in the asphalt and improving the weather resistance of the asphalt composition, the asphalt modifier of the present invention is preferably a melt-kneaded product.

[0009] The reason why the effects of the present invention are achieved is unclear, but is thought to be as follows. Because carbon black is resistant to degradation by ultraviolet rays, its use in asphalt pavement can improve the weather resistance of roads. However, when carbon black is directly added to asphalt or modified asphalt and mixed, there is a problem that the carbon black aggregates in the asphalt, and the amount of carbon black added to improve weather resistance is problematic. The asphalt modifier of the present invention contains resin A and carbon black, and the mass ratio of inorganic filler (excluding carbon black) to carbon black [inorganic filler / carbon black] is 1 or less. Therefore, even if the carbon black content is kept to 2.5 mass% or less, by mixing the asphalt modifier with asphalt, the carbon black can be uniformly dispersed in the asphalt. Therefore, it is believed that the weather resistance of asphalt compositions can be improved by using the asphalt modifier of the present invention.

[0010] Definitions of various terms used in this specification are provided below. In a polyester resin, a "structural unit derived from an alcohol component" refers to a structure in which a hydrogen atom is removed from a hydroxy group of an alcohol component, and a "structural unit derived from a carboxylic acid component" refers to a structure in which a hydroxy group is removed from a carboxy group of a carboxylic acid component. The term "carboxylic acid component" encompasses not only the carboxylic acid itself, but also anhydrides that decompose during the reaction to produce an acid, and alkyl esters of carboxylic acids (for example, alkyl groups having 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 that is the alcohol residue of the ester is not included in the number of carbon atoms of the carboxylic acid.

[0011] <Resin A> From the viewpoint of weather resistance, Resin A is preferably a thermoplastic resin, and preferably does not have a carbon-carbon double bond within its structure. Furthermore, the melting point or softening point of Resin A is preferably 270°C or lower, more preferably 240°C or lower, and even more preferably 200°C or lower. The lower limit is, for example, 80°C or higher. The melting point and softening point of Resin A can be adjusted by the raw material monomer composition, molecular weight, catalyst amount, or reaction conditions, and are determined by the method described in the Examples below. Specific examples of Resin A include polyester resin, ethylene-vinyl acetate copolymer resin, polyethylene resin, polypropylene resin, nylon resin, polystyrene resin, acrylonitrile-styrene copolymer resin (AS resin), polyvinyl chloride resin (PVC resin), polyvinyl alcohol resin (PVA resin), acrylonitrile-butadiene-styrene copolymer resin (ABS resin), and polyvinylidene chloride resin. Each resin may be used alone or in combination of two or more. From the viewpoints of weather resistance, the aesthetic appearance of the asphalt pavement surface, and blackness, Resin A preferably contains one or more resins selected from polyester resin, ethylene-vinyl acetate copolymer resin, polyethylene resin, polypropylene resin, and nylon resin, more preferably contains one or more resins selected from polyester resin, ethylene-vinyl acetate copolymer resin, polyethylene resin, and polypropylene resin, and even more preferably contains polyester resin.

[0012] [Polyester Resin] The polyester resin is a polycondensation product of an alcohol component and a carboxylic acid component, containing a structural unit derived from an alcohol component and a structural unit derived from a carboxylic acid component. Examples of the polyester resin include amorphous polyester resins and crystalline polyester resins, and the amorphous polyester resin is preferred. Hereinafter, the physical properties of the alcohol component, the carboxylic acid component, and the polyester resin will be described.

[0013] (Alcohol Component) Examples of the alcohol component include chain aliphatic diols, alicyclic diols, aromatic diols, trihydric or higher polyhydric alcohols, etc. These alcohol components may be used alone or in combination of two or more.

[0014] The chain aliphatic diol is preferably a linear or branched chain aliphatic diol having from 2 to 12 carbon atoms in the main chain, more preferably a linear or branched chain aliphatic diol having from 2 to 8 carbon atoms in the main chain. The chain aliphatic diol is preferably a saturated chain aliphatic diol. Specific examples of the chain aliphatic diol include ethylene glycol, 1,2-propanediol, 1,3-propanediol, 1,3-butanediol, 1,4-butanediol, 1,4-butenediol, 1,5-pentanediol, 1,6-hexanediol, neopentyl glycol, 1,10-decanediol, and 1,12-dodecanediol.

[0015] Examples of alicyclic diols include hydrogenated bisphenol A (2,2-bis(4-hydroxycyclohexyl)propane), alkylene oxide adducts of hydrogenated bisphenol A, cyclohexanediol, and cyclohexanedimethanol.

[0016] Examples of aromatic diols include bisphenol A (2,2-bis(4-hydroxyphenyl)propane) and alkylene oxide adducts of bisphenol A. Examples of alkylene oxide adducts of bisphenol A include alkylene oxide adducts of bisphenol A represented by the following formula (I):

[0017]

[0018] [In the formula, OR 1 and R 1 O is an alkylene oxide, and R 1 is an alkylene group having 2 or 3 carbon atoms, x and y are positive numbers indicating the average number of moles of alkylene oxide added, and the sum of x and y is preferably 1 or more, more preferably 1.5 or more, and is preferably 16 or less, more preferably 8 or less, and even more preferably 4 or less.

[0019] Examples of the alkylene oxide adduct of bisphenol A represented by formula (I) include a propylene oxide adduct of bisphenol A and an ethylene oxide adduct of bisphenol A. These alkylene oxide adducts of bisphenol A can be used alone or in combination of two or more.

[0020] The trihydric or higher polyhydric alcohol is preferably a trihydric alcohol, and examples of the trihydric or higher polyhydric alcohol include glycerin, pentaerythritol, trimethylolpropane, and sorbitol.

[0021] The alcohol component may further contain a monohydric aliphatic alcohol from the viewpoint of adjusting physical properties. Examples of the monohydric aliphatic alcohol include lauryl alcohol, myristyl alcohol, palmityl alcohol, and stearyl alcohol. These monohydric aliphatic alcohols may be used alone or in combination of two or more.

[0022] (Carboxylic Acid Component) Examples of the carboxylic acid component include aliphatic dicarboxylic acids, aromatic dicarboxylic acids, and polycarboxylic acids having a valence of 3 to 6. These carboxylic acid components can be used alone or in combination of two or more.

[0023] The aliphatic dicarboxylic acid preferably has 4 or more carbon atoms in the main chain and 10 or less, more preferably 8 or less, and even more preferably 6 or less, such as fumaric acid, maleic acid, oxalic acid, malonic acid, citraconic acid, itaconic acid, glutaconic acid, succinic acid, adipic acid, suberic acid, azelaic acid, sebacic acid, dodecanedioic acid, succinic acid substituted with an alkyl group having 1 to 20 carbon atoms or an alkenyl group having 2 to 20 carbon atoms, or anhydrides or alkyl esters thereof (e.g., alkyl groups having 1 to 3 carbon atoms). Examples of substituted succinic acids include dodecylsuccinic acid, dodecenylsuccinic acid, and octenylsuccinic acid. Succinic acid substituted with an alkyl group having from 1 to 20 carbon atoms or an alkenyl group having from 2 to 20 carbon atoms, or an anhydride thereof, can be produced, for example, according to the description in JP-A-2008-145712. Commercially available products can also be used.

[0024] Examples of aromatic dicarboxylic acids include phthalic acid, terephthalic acid, isophthalic acid, naphthalenedicarboxylic acid, anhydrides thereof, and alkyl esters thereof (for example, alkyl groups having from 1 to 3 carbon atoms). Among these aromatic dicarboxylic acids, isophthalic acid and terephthalic acid are preferred, and terephthalic acid is more preferred, from the viewpoints of suppressing aggregate scattering and weather resistance.

[0025] The trivalent or more and hexavalent polycarboxylic acid is preferably a trivalent carboxylic acid. Examples of the trivalent or more and hexavalent polycarboxylic acid include trimellitic acid, 2,5,7-naphthalenetricarboxylic acid, pyromellitic acid, and acid anhydrides thereof.

[0026] The carboxylic acid component may further contain a monovalent aliphatic carboxylic acid from the viewpoint of adjusting physical properties. Examples of the monovalent aliphatic carboxylic acid include monovalent aliphatic carboxylic acids having from 12 to 20 carbon atoms, such as lauric acid, myristic acid, palmitic acid, stearic acid, and alkyl (having from 1 to 3 carbon atoms) esters of these acids. These monovalent aliphatic carboxylic acids may be used alone or in combination of two or more.

[0027] (Structural units derived from polyethylene terephthalate) The polyester resin preferably contains a polycondensate of an alcohol component, a carboxylic acid compound, and polyethylene terephthalate (PET). The polyethylene terephthalate may contain small amounts of components such as butanediol and isophthalic acid in addition to structural units derived from ethylene glycol and terephthalic acid. The polyethylene terephthalate is preferably recycled polyethylene terephthalate. When the polyester resin contains structural units consisting of ethylene glycol and terephthalic acid derived from polyethylene terephthalate, the "structural units derived from alcohol components" include structural units derived from ethylene glycol derived from polyethylene terephthalate, and the "structural units derived from carboxylic acid components" include structural units derived from terephthalic acid derived from polyethylene terephthalate.

[0028] (Preferred Embodiment of Polyester Resin) In a preferred embodiment of the polyester resin, the content of structural units derived from aromatic diols in 100 mol% of structural units derived from alcohol components is preferably 10 mol% or more and 70 mol% or less, more preferably 20 mol% or more, even more preferably 30 mol% or more, and more preferably 60 mol% or less, and even more preferably 50 mol% or less. In a preferred embodiment of the polyester resin, the content of structural units derived from aliphatic diols in 100 mol% of structural units derived from alcohol components is preferably 30 mol% or more and 90 mol% or less, more preferably 40 mol% or more, even more preferably 50 mol% or more, and more preferably 80 mol% or less, and even more preferably 70 mol% or less. In a preferred embodiment of the polyester resin, the content of structural units derived from aromatic dicarboxylic acids in 100 mol% of structural units derived from carboxylic acid components is preferably 50 mol% or more and 98 mol% or less, more preferably 60 mol% or more, even more preferably 70 mol% or more, and more preferably 95 mol% or less, and even more preferably 90 mol% or less. In a preferred embodiment of the polyester resin, the content of structural units derived from aliphatic dicarboxylic acids in 100 mol% of structural units derived from carboxylic acid components is preferably 1 mol% or more and 20 mol% or less, more preferably 3 mol% or more, even more preferably 6 mol% or more, and more preferably 16 mol% or less, and even more preferably 12 mol% or less. In a preferred embodiment of the polyester resin, the content of the polycondensate of an alcohol component, a carboxylic acid component, and polyethylene terephthalate (PET) in the polyester resin is preferably 70 mass% or more, more preferably 80 mass% or more, even more preferably 90 mass% or more, even more preferably 95 mass% or more, and 100 mass% or less, from the viewpoint of weather resistance.

[0029] (Physical Properties of Polyester Resin) From the viewpoint of weather resistance, the softening point of the polyester resin is preferably 80° C. or higher and 140° C. or lower, more preferably 85° C. or higher, even more preferably 90° C. or higher, and 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 point of the polyester resin is preferably 30° C. or higher and 95° C. or lower, more preferably 40° C. or higher, even more preferably 50° C. or higher, and more preferably 85° C. or lower, even more preferably 75° C. or lower, and even more preferably 65° C. or lower. From the viewpoint of weather resistance, the acid value of the polyester resin is preferably 1 mgKOH / g or higher and 30 mgKOH / g or lower, more preferably 3 mgKOH / g or higher, even more preferably 5 mgKOH / g or higher, and more preferably 20 mgKOH / g or lower, and even more preferably 15 mgKOH / g or lower. From the viewpoint of weather resistance, the hydroxyl value of the polyester resin is preferably 1 mgKOH / g or more and 40 mgKOH / g or less, more preferably 10 mgKOH / g or more, even more preferably 20 mgKOH / g or more, and more preferably 35 mgKOH / g or less, even more preferably 30 mgKOH / g or less.

[0030] The softening point, glass transition point, acid value, and hydroxyl value of the polyester resin can be measured by the methods described in the Examples. The softening point, glass transition point, acid value, and hydroxyl value can be adjusted by the raw material monomer composition, molecular weight, catalyst amount, or reaction conditions.

[0031] The polyester resin may be modified to such an extent that its properties are not substantially impaired. Specific examples of modified polyester resins include polyester resins grafted or blocked with phenol, urethane, epoxy, or the like, by methods described in JP-A Nos. 11-133668, 10-239903, and 8-20636. A preferred modified polyester resin is a urethane-modified polyester resin obtained by urethane-extending a polyester resin with a polyisocyanate compound.

[0032] (Method for producing polyester resin) The polyester resin can be produced, for example, by polycondensing the alcohol component and the carboxylic acid component described above. The temperature of the polycondensation reaction is adjusted to the reactivity and is preferably 160°C or higher, more preferably 190°C or higher, and even more preferably 200°C or higher, and is preferably 260°C or lower, more preferably 250°C or lower, and even more preferably 240°C or lower.

[0033] When a polyester resin contains structural units derived from ethylene glycol derived from polyethylene terephthalate and structural units derived from terephthalic acid derived from polyethylene terephthalate, the amount of polyethylene terephthalate present in the raw material is preferably 5% by mass or more and 65% by mass or less, more preferably 15% by mass or more, even more preferably 25% by mass or more, and more preferably 55% by mass or less, and even more preferably 45% by mass or less, based on the total amount of polyethylene terephthalate, alcohol component, and carboxylic acid component. Adding polyethylene terephthalate during the polycondensation reaction of the alcohol component and the carboxylic acid component causes a transesterification reaction, resulting in a polyester resin in which structural units derived from polyethylene terephthalate are incorporated into structural units derived from the alcohol component and structural units derived from the carboxylic acid component. Polyethylene terephthalate may be present from the start of the polycondensation reaction, or may be added to the reaction system during the polycondensation reaction. The timing of adding polyethylene terephthalate is preferably when the reaction rate between the alcohol component and the carboxylic acid component is 10% or less, more preferably 5% or less. The reaction rate refers to the value calculated by dividing the amount of reaction water (moles) by the theoretical amount of water produced (moles) × 100.

[0034] In order to increase the reaction rate, an esterification catalyst can be used in the polycondensation reaction. Examples of esterification catalysts include tin(II) compounds that do not have a Sn—C bond, such as tin(II) di(2-ethylhexanoate). From the viewpoint of reaction rate, the amount of the esterification catalyst used is preferably 0.01 to 2.0 parts by mass, more preferably 0.1 to 0.2 parts by mass, even more preferably 0.2 to 1.5 parts by mass, and even more preferably 1.0 to 1.0 parts by mass, per 100 parts by mass of raw material monomer. In addition to the esterification catalyst, an esterification promoter can be used in the polycondensation reaction. Examples of the esterification promoter include pyrogallol compounds such as gallic acid. The amount of the esterification promoter used is preferably 0.001 to 0.20 parts by mass, more preferably 0.005 to 0.01 parts by mass, even more preferably 0.01 to 1.0 parts by mass, per 100 parts by mass of raw material monomer.

[0035] [Ethylene-vinyl acetate copolymer resin] Ethylene-vinyl acetate copolymer resin is an addition polymer of ethylene and vinyl acetate, and the polymerization form may be block or random. In the ethylene-vinyl acetate copolymer resin, the content of structural units derived from vinyl acetate is preferably 10% by mass or more and 35% by mass or less, and from the viewpoint of dispersing carbon black in asphalt and improving weather resistance, it is more preferably 15% by mass or more, even more preferably 20% by mass or more, and more preferably 30% by mass or less.

[0036] [Polyethylene Resin] Specific examples of polyethylene resins include high-density polyethylene (HDPE), medium-density polyethylene (MDPE), low-density polyethylene (LDPE), very-low-density polyethylene (ULDPE), and linear low-density polyethylene (LLDPE). From the viewpoint of weather resistance, medium-density polyethylene, low-density polyethylene, very-low-density polyethylene, and linear low-density polyethylene are preferred, and low-density polyethylene, very-low-density polyethylene, and linear low-density polyethylene are more preferred.

[0037] [Polypropylene Resin] The polypropylene resin may be a propylene homopolymer or a copolymer of propylene and an α-olefin, with a propylene homopolymer being preferred. The polymerization form of the propylene and α-olefin copolymer may be random or block. The carbon number of the α-olefin is preferably 2 or more and 18 or less. Specific examples of α-olefins include ethylene, propylene, butene, pentene, hexene, heptene, octene, and nonene. The content of propylene-derived structural units in the propylene and α-olefin copolymer is preferably 70% by mass or more, more preferably 80% by mass or more, and even more preferably 90% by mass or more, and 99% by mass or less.

[0038] [Nylon Resin] Specific examples of nylon resins include polycapramide (nylon 6), poly-ω-aminoheptanoic acid (nylon 7), poly-ω-aminononanoic acid (nylon 9), polyundecaneamide (nylon 11), polylauryl lactam (nylon 12), polyethylenediamineadipamide (nylon 2,6), polytetramethyleneadipamide (nylon 4,6), polyhexamethyleneadipamide (nylon 6,6), polyhexamethylenesebacamide (nylon 6,10), polyhexamethylenedodecamide (nylon 6,12), polyoctamethyleneadipamide (nylon 8,6), polydecamethyleneadipamide (nylon 10,8), caprolactam / lauryl lactam copolymer (nylon 6 / 12), caprolactam / ω-amino Examples of the nylon copolymer include aliphatic nylons and copolymers thereof, such as nononanoic acid copolymer (nylon 6 / 9), caprolactam / hexamethylenediammonium adipate copolymer (nylon 6 / 6,6), lauryllactam / hexamethylenediammonium adipate copolymer (nylon 12 / 6,6), ethylenediamine adipamide / hexamethylenediammonium adipate copolymer (nylon 2,6 / 6,6), caprolactam / hexamethylenediammonium adipate / hexamethylenediammonium sebacate copolymer (nylon 6,6 / 6,10), and ethyleneammonium adipate / hexamethylenediammonium adipate / hexamethylenediammonium sebacate copolymer (nylon 6 / 6,6 / 6,10).

[0039] From the viewpoint of weather resistance, the total content of polyester resin, ethylene-vinyl acetate copolymer resin, polyethylene resin, polypropylene resin, and nylon resin in resin A is preferably 70% by mass or more, more preferably 80% by mass or more, even more preferably 90% by mass or more, and still more preferably 95% by mass or more, and is 100% by mass or less.

[0040] (Content of Resin A in Asphalt Modifier) ​​From the viewpoint of weather resistance, the content of Resin A in the asphalt modifier is preferably 97.0 mass% or more, more preferably 97.5 mass% or more, even more preferably 98.0 mass% or more, still more preferably 98.5 mass% or more, of the total mass of the asphalt modifier. It is less than 100 mass%, preferably 99.99 mass% or less, more preferably 99.95 mass% or less, still more preferably 99.7 mass% or less.

[0041] <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 dibutyl phthalate (DBP) oil absorption of the carbon black is preferably 70 ml / 100 g or more and 130 ml / 100 g or less, more preferably 80 ml / 100 g or more, even more preferably 90 ml / 100 g or more, and more preferably 120 ml / 100 g or less, even more preferably 110 ml / 100 g or less. The DBP oil absorption of the carbon black is measured in accordance with ISO 4656 (JIS K 6217-4:2008) "Determination of oil absorption." From the viewpoint of weather resistance, the nitrogen adsorption specific surface area of ​​carbon black is preferably 10 m ２ / g or more, more preferably 30m ２ / g or more, more preferably 50m ２ / g or more, more preferably 70m ２ / g or more, and preferably 200m ２ / g or less, more preferably 100m ２ / g or less, more preferably 85m ２ From the above viewpoint, the nitrogen adsorption specific surface area of ​​the carbon black is preferably 10 m ２ / g or more 200m ２ / g or less, more preferably 30m ２ / g or more 100m ２ / g or less, more preferably 50m ２ / g or more 85m２ The nitrogen adsorption specific surface area of ​​carbon black is measured in accordance with JIS K 6217-2:2001. Carbon black may be used singly or in combination of two or more types.

[0042] (Carbon Black Content in Asphalt Modifier) ​​From the viewpoint of weather resistance, the carbon black content in the asphalt modifier is 2.5 mass% or less of the total mass of the asphalt modifier. From the viewpoint of weather resistance, the content is preferably 0.01 mass% or more and 2.0 mass% or less, more preferably 1.5 mass% or less, more preferably 0.05 mass% or more, even more preferably 0.3 mass% or more, and even more preferably 0.7 mass% or more.

[0043] From the viewpoint of increasing the dispersibility of carbon black and improving weather resistance, the asphalt modifier preferably has a blackness of 7 or more and 40 or less, more preferably 30 or less, even more preferably 20 or less, and still more preferably 15 or less. The blackness can be measured by the method described in the examples.

[0044] The asphalt modifier of the present invention can be used, for example, by mixing it with asphalt to obtain an asphalt composition. Heated aggregate is added to the obtained asphalt composition to form an asphalt mixture, which can then be used for paving. The asphalt modifier of the present invention can be suitably used as an asphalt modifier to be blended into asphalt mixtures containing aggregate.

[0045] <Inorganic Filler> In the present invention, the inorganic filler means an inorganic filler other than carbon black that is commonly used in asphalt modifiers, and specific examples include silica and diatomaceous earth.

[0046] (Content of inorganic filler in asphalt modifier) ​​In the asphalt modifier, the content of inorganic filler per 100 parts by mass of resin A is preferably 1 part by mass or less, more preferably 0.5 parts by mass or less, even more preferably 0.1 parts by mass or less, and may even be 0 parts by mass, from the viewpoint of durability of asphalt pavement.

[0047] In the asphalt modifier, the mass ratio of inorganic filler to carbon black [inorganic filler / carbon black] is 1 or less, preferably 0.5 or less, more preferably 0.1 or less, and may be 0, from the viewpoint of the durability of the asphalt pavement.

[0048] [Method for producing asphalt modifier] The asphalt modifier can be obtained, for example, by heating resin A, carbon black, and, if necessary, an inorganic filler to melt resin A, and kneading them in a commonly used mixer until the carbon black and inorganic filler are uniformly dispersed in resin A. Commonly used mixers include a homomixer, dissolver, paddle mixer, ribbon mixer, screw mixer, planetary mixer, vacuum countercurrent mixer, roll mill, twin-screw extruder, etc.

[0049] [Asphalt Composition] The asphalt composition of the present invention contains asphalt and the resin A and carbon black that constitute the asphalt modifier.

[0050] <Asphalt> The asphalt composition of the present invention contains asphalt. Various asphalts can be used as the asphalt. Examples include straight asphalt, which is petroleum asphalt for paving, as well as modified asphalt. Straight asphalt is the residual bituminous material obtained by subjecting crude oil to atmospheric distillation equipment, vacuum distillation equipment, etc. Modified asphalts include blown asphalt and polymer-modified asphalt (hereinafter also referred to as "polymer-modified asphalt") modified with polymeric 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 oxidizing it by blowing air into 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.

[0051] (Thermoplastic elastomer) Examples of the thermoplastic elastomer in the polymer-modified asphalt include 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-based thermoplastic elastomer, polyolefin-based thermoplastic elastomer, isobutylene / isoprene copolymer, polyisoprene, polychloroprene, synthetic rubber other than the above, and at least one selected from natural rubber.

[0052] Among these, from the viewpoint of the durability of asphalt pavement, 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, and even more preferably at least one selected from SBR and SBS. From the viewpoint of the durability of asphalt pavement, the content of the thermoplastic elastomer in the polymer modified asphalt is preferably 0.1% by mass or more and 30% by mass or less, more preferably 0.5% by mass or more, even more preferably 1% by mass or more, and more preferably 15% by mass or less, even more preferably 7% by mass or less.

[0053] From the viewpoint of the durability of asphalt pavement, the asphaltene content in asphalt is preferably 13% by mass or more and 35% by mass or less, more preferably 15% by mass or more, even more preferably 17% by mass or more, and more preferably 27% by mass or less, even more preferably 24% by mass or less. The asphaltene content in asphalt is a value measured in accordance with Japan Petroleum Institute standard JPI-5S-22-83, "Method for Composition Analysis of Asphaltene by Column Chromatography."

[0054] The total content of straight asphalt and polymer-modified asphalt in the asphalt composition is preferably 60% by mass or more and less than 100% by mass, more preferably 70% by mass or more, even more preferably 80% by mass or more, even more preferably 90% by mass or more, and more preferably 99.5% by mass or less. From the viewpoint of exhibiting asphalt performance, the total content is preferably equal to or more than the lower limit, and from the viewpoint of storage stability, it is preferably equal to or less than the upper limit.

[0055] (Resin A and Carbon Black Contents, etc.) From the viewpoint of durability and storage stability of the asphalt pavement, the total content of Resin A and carbon black in the asphalt composition is preferably 0.5 parts by mass or more and 15 parts by mass or less, more preferably 0.8 parts by mass or more, and more preferably 12 parts by mass or less, even more preferably 10 parts by mass or less, and even more preferably 8 parts by mass or less, per 100 parts by mass of asphalt.

[0056] The carbon black content in the resin A and the carbon black is 2.5% by mass or less. From the viewpoint of weather resistance, the content is preferably 0.01% by mass or more and 2.0% by mass or less, more preferably 1.5% by mass or less, and more preferably 0.05% by mass or more.

[0057] In the asphalt composition, the content of inorganic filler per 100 parts by mass of resin A is preferably 1 part by mass or less, more preferably 0.5 parts by mass or less, even more preferably 0.1 parts by mass or less, and may even be 0 parts by mass, from the viewpoint of the durability of the asphalt pavement.

[0058] The mass ratio of inorganic filler (excluding carbon black) to carbon black in the asphalt composition [inorganic filler / carbon black] is 1 or less, preferably 0.5 or less, more preferably 0.1 or less, and even more preferably 0.01 or less, from the viewpoint of durability and storage stability of the asphalt pavement, and may even be 0. Specific examples of inorganic fillers are as described above, including silica and diatomaceous earth.

[0059] <Dispersant> The asphalt composition may further contain a dispersant. Examples of dispersants include polymer 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 naphthalenesulfonic acid formalin condensates. In the present invention, the term "polymer dispersant" refers to a dispersant having a weight average molecular weight of 1,000 or more. However, from the viewpoint of storage stability, the content of the dispersant is preferably less than 1 part by mass, more preferably less than 0.5 parts by mass, per 100 parts by mass of resin A, and even more preferably substantially no dispersant is contained.

[0060] <Other Components> The asphalt composition may further contain an organic acid. The organic acid may be acetic acid, citric acid, malic acid, fumaric acid, or maleic acid, or may be an organic acid anhydride. However, from the viewpoint of storage stability, the content of the organic acid is preferably less than 1 part by mass, more preferably less than 0.5 parts by mass, per 100 parts by mass of resin A, and even more preferably, the organic acid may be substantially absent. Furthermore, from the viewpoint of the durability and storage stability of the asphalt pavement, the mass ratio of the organic acid to the carbon black [organic acid / carbon black] in the asphalt composition is 1 or less, preferably 0.5 or less, more preferably 0.1 or less, even more preferably 0.01 or less, and may even be 0.

[0061] From the viewpoint of weather resistance, the asphalt composition of the present invention is designed to be irradiated with ultraviolet light of 300 to 400 nm at a rate of 150 W / m ２ Carbonyl index (C Ａ ) and the carbonyl index (CＢ ) preferably satisfies the following formula (1): Ａ / C Ｂ <2 (1) The carbonyl index is the carbonyl index at 1600 cm of the asphalt composition measured by Fourier transform infrared spectroscopy (FT-IR). －１ 1700 cm for absorbance －１ The ratio of absorbance (1700 cm －１ absorbance / 1600 cm －１ The lower limit of the formula (1) is, for example, 1.0 from the viewpoint of production.

[0062] [Method for producing asphalt composition] The method for producing an asphalt composition of the present invention comprises the following steps 1 and 2, in this order: Step 1: Mixing resin A and carbon black to obtain an asphalt modifier Step 2: Mixing asphalt with the asphalt modifier obtained in step 1 However, in the asphalt modifier obtained in step 1, the carbon black content is 2.5 mass% or less, and the mass ratio of inorganic filler (excluding carbon black) to carbon black [inorganic filler / carbon black] is 1 or less, from the viewpoint of the durability and storage stability of asphalt pavement.

[0063] Step 1 is the same as the above-mentioned [Method for Producing Asphalt Modifier]. In Step 2, asphalt is heated and melted, the asphalt modifier is added, and the mixture is stirred and mixed in a commonly used mixer until the resin A and carbon black that constitute the asphalt modifier are 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 countercurrent mixers, roll mills, twin-screw extruders, etc.

[0064] The mixing temperature of the asphalt and the asphalt modifier is preferably 140°C or higher and 230°C or lower, more preferably 150°C or higher, even more preferably 160°C or higher, and more preferably 210°C or lower, and even more preferably 200°C or lower, from the viewpoint of uniformly dispersing the resin A and carbon black constituting the asphalt modifier in the asphalt. Furthermore, the mixing time of the asphalt and the asphalt modifier is preferably 5 minutes or higher and 5 hours or lower, more preferably 10 minutes or higher, even more preferably 20 minutes or higher, and more preferably 3 hours or lower, even more preferably 1 hour or lower, from the viewpoint of uniformly dispersing the polyester in the asphalt. The asphalt composition of the present invention is a binder composition, and can be used for paving, for example, by adding aggregate to the asphalt composition to form an asphalt mixture. That is, the asphalt composition of the present invention is suitable for paving, particularly for road paving.

[0065] [Asphalt Mixture] An asphalt mixture, which is a suitable example of the use of the asphalt composition, will now be described. The asphalt mixture contains aggregate and the above-mentioned asphalt composition. That is, the asphalt mixture contains at least aggregate, asphalt, resin A, and carbon black.

[0066] <Aggregate> The aggregate can be selected from any of a variety of materials, including crushed stone, boulders, gravel, sand, recycled aggregate, and ceramics. Furthermore, the aggregate can be either a coarse aggregate with a particle size of 2.36 mm or more, or a fine aggregate with a particle size of less than 2.36 mm, with a combination of coarse and fine aggregate being preferred. From the viewpoint of the durability of the asphalt pavement, the aggregate content in the asphalt mixture is preferably 85% by mass or more and 98% by mass or less, more preferably 90% by mass or more, more preferably 92% by mass or more, and more preferably 97% by mass or less, and even more preferably 96% by mass or less.

[0067] <Additives> In addition to the above aggregate, asphalt, resin A, and carbon black, the asphalt mixture may contain, as necessary, various additives that have conventionally been used in asphalt mixtures, such as film-forming agents, thickening stabilizers, emulsifiers, etc. The total content of these additives in the asphalt mixture is preferably 50% by mass or less, more preferably 25% by mass or less, and even more preferably 5% by mass or less.

[0068] [Manufacturing Method of Asphalt Mixture] There are no particular limitations on the manufacturing method of the asphalt mixture, and any manufacturing method may be used. Usually, the manufacturing method can be carried out in accordance with the manufacturing method of an asphalt mixture containing aggregate and asphalt. Specifically, a method of adding the above-mentioned asphalt composition to heated aggregate and mixing it can be mentioned.

[0069] The temperature of the heated aggregate is preferably 130° C. or higher and 230° C. or lower, more preferably 150° C. or higher, even more preferably 170° C. or higher, more preferably 210° C. or lower, and even more preferably 200° C. or lower. From the viewpoint of the durability of the asphalt pavement, the temperature of the heated aggregate is preferably above the lower limit, and from the viewpoint of preventing thermal degradation of the asphalt, it is preferably below the upper limit.

[0070] The mixing temperature of the aggregate and asphalt composition is preferably 130°C or higher and 230°C or lower, more preferably 150°C or higher, even more preferably 170°C or higher, more preferably 210°C or lower, and even more preferably 200°C or lower. From the viewpoint of the durability of the asphalt pavement, the mixing temperature of the aggregate and asphalt composition is preferably above the lower limit, and from the viewpoint of preventing thermal deterioration of the asphalt, it is preferably below the upper limit. The mixing time of the aggregate and asphalt composition is not particularly limited, and is preferably from 30 seconds to 2 hours, more preferably 1 minute or higher, even more preferably 2 minutes or higher, and more preferably 1 hour or lower, even more preferably 30 minutes or lower.

[0071] From the viewpoint of the durability of the asphalt pavement, the method for producing an asphalt mixture preferably includes a step of mixing aggregate and an 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 step 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.

[0072] [Road Paving Method] 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 a step of applying the asphalt mixture to a road to form an asphalt pavement layer. Specifically, the road paving method includes a step of mixing the asphalt composition with heated aggregate to obtain an asphalt mixture (Step I), and a step of applying the asphalt mixture obtained in Step I to a road to form an asphalt pavement layer (Step II). The asphalt pavement layer is preferably a base layer or a surface layer.

[0073] The asphalt mixture may be compacted and applied in the same manner using a known construction machine. When used as a heated asphalt mixture, the compaction temperature is preferably 100°C or higher and 200°C or lower, more preferably 120°C or higher, even more preferably 130°C or higher, and more preferably 180°C or lower, from the viewpoint of the durability of the asphalt pavement.

[0074] The present invention includes the following embodiments. <1> An asphalt modifier comprising resin A and carbon black, wherein the carbon black content is 2.5 mass% or less, and the mass ratio of the inorganic filler (excluding carbon black) to the carbon black [inorganic filler / carbon black] is 1 or less. <2> The asphalt modifier according to <1>, comprising a melt-kneaded mixture of resin A and carbon black. <3> The asphalt modifier according to <1> or <2>, having a blackness of 7 or more and 40 or less, preferably 7 or more and 30 or less, more preferably 7 or more and 20 or less, and even more preferably 7 or more and 15 or less. <4> The asphalt modifier according to any one of <1> to <3>, wherein resin A comprises one or more selected from polyester resin, ethylene-vinyl acetate copolymer resin, polyethylene resin, polypropylene resin, and nylon resin. <5> The asphalt modifier according to <4>, wherein the polyester resin comprises an alcohol component, a carboxylic acid compound, and a polycondensate of polyethylene terephthalate. <6> The asphalt modifier according to any one of <1> to <5>, wherein the content of resin A is 97.0% by mass or more, preferably 97.5% by mass or more, more preferably 98.0% by mass or more, and even more preferably 98.5% by mass or more. <7> The asphalt modifier according to any one of <1> to <6>, wherein the content of resin A is less than 100% by mass, preferably 99.99% by mass or less, more preferably 99.95% by mass or less, and even more preferably 99.7% by mass or less. <8> The asphalt modifier according to any one of <1> to <7>, wherein the content of resin A is 97.0% by mass or more but less than 100% by mass, preferably 97.5% by mass or more but less than 99.99% by mass, and more preferably 98.0% by mass or more but less than 99.95% by mass. <9> The asphalt modifier according to any one of <1> to <8>, wherein the content of carbon black is 2.0% by mass or less, preferably 1.5% by mass or less. <10> The carbon black content is 0.01% by mass or more, preferably 0.05% by mass or more, more preferably 0.3% by mass or more, and even more preferably 0.7% by mass or more. The asphalt modifier according to any one of <1> to <9>.<11> The asphalt modifier according to any one of <1> to <10>, wherein the carbon black content is 0.01% by mass or more and 2.5% by mass or less, preferably 0.05% by mass or more and 2.0% by mass or less, and more preferably 0.3% by mass or more and 1.5% by mass or less. <12> The asphalt modifier according to <1> to <11>, wherein the mass ratio of the inorganic filler to the carbon black [inorganic filler / carbon black] is 0.5 or less, preferably 0.1 or less, and more preferably 0. <13> An asphalt modifier comprising resin A and carbon black, wherein the carbon black content is 0.01% by mass or more and 2.5% by mass or less, the resin A content is 97.5% by mass or more and 99.9% by mass or less, and the mass ratio of the inorganic filler (excluding carbon black) to the carbon black [inorganic filler / carbon black] is 1 or less. <14> An asphalt modifier comprising resin A and carbon black, wherein the carbon black content is 0.01% by mass or more and 2.5% by mass or less, the resin A content is 97.5% by mass or more and 99.9% by mass or less, resin A is polyester, and the mass ratio of the inorganic filler (excluding carbon black) to the carbon black [inorganic filler / carbon black] is 1 or less. <15> An asphalt composition comprising asphalt and the asphalt modifier according to any one of <1> to <14>. <16> The asphalt composition according to <15>, wherein the asphalt composition is exposed to ultraviolet light of 300 to 400 nm at 150 W / m. ２ Carbonyl index (C Ａ ) and the carbonyl index (C Ｂ ) satisfies the following formula (1): Ａ / C Ｂ <2 (1) The carbonyl index is the carbonyl index at 1600 cm of the asphalt composition measured by Fourier transform infrared spectroscopy. －１ 1700 cm for absorbance －１ The ratio of absorbance (1700 cm －１ absorbance / 1600 cm －１<17> A method for producing an asphalt composition, comprising the following steps 1 and 2 in this order: Step 1: mixing resin A and carbon black to obtain an asphalt modifier; Step 2: mixing asphalt with the asphalt modifier obtained in step 1; provided that the carbon black content in the asphalt modifier obtained in step 1 is 2.5 mass% or less, and the mass ratio of the inorganic filler (excluding carbon black) to the carbon black [inorganic filler / carbon black] is 1 or less.

[0075] The present invention will be specifically explained below with reference to examples, but the present invention is not limited to these examples in any way.

[0076] The physical properties of Resin A and other resins were measured and evaluated using the following methods. [Measurement Methods] [Softening Point, Melting Point, and Glass Transition Point] (1) Softening Point Using a flow tester "CFT-500D" (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 the plunger, and the sample was extruded from a nozzle with a diameter of 1 mm and a length of 1 mm. The plunger depression amount of the flow tester was plotted against the temperature, and the temperature at which half of the sample flowed out was taken as the softening point. (2) Melting Point and Glass Transition Point Using a differential scanning calorimeter "Q-100" (TA Instruments Japan Co., Ltd.), 0.01 to 0.02 g of sample was weighed into an aluminum pan, heated to 200°C, and cooled to 0°C at a cooling rate of 10°C / min. Measurements were then taken while the sample was heated to 150°C at a heating rate of 10°C / min. The melting point was determined as the temperature of the peak with the largest peak area if the difference between the temperature and the softening point was within 20° C. The glass transition point was determined as the temperature at the intersection of an extension of the baseline below the maximum endothermic peak temperature and a tangent line showing the maximum slope from the rising part of the peak to the peak apex.

[0077] [Acid Value and Hydroxyl Value of Polyester Resin] The acid value and hydroxyl value of the polyester resin were measured according to the method of JIS K0070: 1992. However, the measurement solvent was changed from the mixed solvent of ethanol and ether specified in JIS K0070: 1992 to a mixed solvent of acetone and toluene (acetone:toluene = 1:1 (volume ratio)).

[0078] Production Example (Polyester Resin) The BPA-PO shown in Table 1 was placed in a 5-liter four-neck flask equipped with a thermometer, a stainless steel stirring rod, a downflow condenser, and a nitrogen inlet tube, and heated to 100°C. After adding terephthalic acid at 100°C, the temperature was increased to 180°C at 0.5°C / min. PET was added at 180°C, and the temperature was increased to 235°C at 0.5°C / min. Under a nitrogen atmosphere, 20 g of tin(II) di(2-ethylhexanoate) and 2 g of gallic acid were added at 235°C, and a condensation polymerization reaction was carried out at 235°C for 6 hours. After cooling to 180°C, branched alkenyl succinic anhydride (alkenyl group carbon number: 12, dodecenyl) was added. The temperature was increased from 180°C to 220°C at 0.3°C / min, and the reaction was continued at 220°C and 20 kPa until the softening point shown in Table 1 was reached, yielding a polyester resin.

[0079]

[0080] Example a1 (Production of Asphalt Modifier a1) While rotating a baby roll heated to 180 ° C, 99.9 g of the polyester resin synthesized in the above Production Example and 0.1 g 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 completed, the mixture was removed from the kneader, and the mixture adhering to the baby roll was scraped off and kneaded into the mixture removed from the kneader to obtain Asphalt Modifier a1.

[0081] Examples a2 to a6 and Comparative Examples b1 to b4 (Production of Asphalt Modifiers a2 to a6 and b1 to b4) Asphalt modifiers a2 to a6 were produced in the same manner as Example a1, except that the type of resin and the blending amounts of resin and carbon black were as shown in Table 2. The polyester resin obtained in the production example was designated as asphalt modifier b1. Carbon black was designated as asphalt modifier b2. Asphalt modifiers b3 and b4 were produced in the same manner as Example a1, except that the type of resin and the blending amounts of resin and carbon black were as shown in Table 2.

[0082] [Evaluation] The blackness of the asphalt modifier was measured as follows. The results are shown in Table 2.

[0083] [Blackness] The asphalt modifier was placed in an aluminum container (manufactured by Trusco Nakayama Corporation, product number RC092282 220CC) and dissolved in a dryer at 180 ° C. The container was removed, allowed to stand until it reached room temperature, and then the asphalt modifier was removed from the container. Next, a color difference meter (TES-135A manufactured by TES ELECTRICAL ELECTRONIC CORP.) was applied to the bottom of the removed asphalt modifier (the surface that was in contact with the bottom of the container) to measure, and the Lab value was taken as the blackness. Note that the blackness measurement was not performed on asphalt modifier b2.

[0084]

[0085] Example 1 (Production of Asphalt Composition 1) 50 g of modified asphalt (Resifix, manufactured by Showa Rekisei Kogyo Co., Ltd.) was weighed into a 300 ml stainless steel container and stirred at 300 rpm with a propeller while heating to 180 ° C. After stirring for 10 minutes, 2.5 g of asphalt modifier a1 was added, and the mixture was stirred for 30 minutes to obtain asphalt composition 1. One to two drops of the above asphalt composition 1 were placed on a glass slide, which was then covered with a cover glass and allowed to stand in a dryer at 180 ° C. for 3 minutes. After confirming that the asphalt composition 1 sandwiched between the glass slide and the cover glass had spread and an asphalt coating had formed on the glass slide, the cover glass was immediately removed.

[0086] Examples 2 to 6 and Comparative Examples 1 to 5 (Production of Asphalt Compositions 2 to 6 and c1 to c5) Asphalt compositions 2 to 5 and c1 to c5 were produced in the same manner as in Example 1, except that the types and amounts of asphalt modifiers used were as shown in Table 3. An asphalt coating was formed on a glass slide using each asphalt composition.

[0087] [Evaluation] The asphalt coatings obtained from the asphalt compositions were evaluated as follows. The results are shown in Table 3.

[0088] [Evaluation of CB Dispersibility] The morphology of the asphalt coating on the slide glass was confirmed by bright field observation using a microscope (DSX1000 manufactured by Olympus Corporation). If no carbon black (CB) aggregates of 500 μm or more were observed, the dispersibility of the CB was rated as "good", and if they were observed, the dispersibility of the CB was rated as "poor".

[0089] [Weathering Resistance Test] The asphalt coating on the slide glass obtained in each Example and Comparative Example was subjected to UV light of 150 W / m using a Super Xenon Weather Meter SX75 (Suga Test Instruments Co., Ltd.). ２ The sample was irradiated with ultraviolet light under conditions of an irradiation wavelength of 300 to 400 nm, an internal temperature of 40°C, and a relative humidity of 75%. The slide glass was attached around the lamp so that the ultraviolet light was uniformly irradiated, and the slide glass was irradiated with ultraviolet light for 48 hours while rotating. This was used as the sample after ultraviolet light irradiation. The samples before and after ultraviolet light irradiation were used for the measurements (1) and (2) below.

[0090] (1) Pencil Hardness Measurement Pencil hardness was measured using a pencil scratch tester (manufactured by TP Giken Co., Ltd.) according to JIS K5600-5-4:1990. The asphalt coating formed on a glass slide was scratched with a tester, starting with a high-hardness 9H pencil (uni-pencil for pencil scratch value test) and gradually decreasing the hardness. The scratches were observed using a microscope (DSX1000 manufactured by Olympus Corporation), and the pencil hardness at which the coating was scraped and the glass was exposed was determined. The highest pencil hardness at which the coating was scraped and the glass was not exposed was taken as the pencil hardness of the asphalt coating. For example, if the glass was exposed by scraping with 4H and not exposed by 3H, the pencil hardness of the asphalt coating was taken as 3H. (2) FT-IR Measurement (Calculation of Carbonyl Index Increment) FT-IR measurement was performed using an apparatus manufactured by Thermo Fisher Scientific Inc. Measurement was performed using a sample before and after UV irradiation, and the following carbonyl indexes (I) and (II) were calculated from the obtained absorption peak curves, and the carbonyl index increment was calculated using the following formula. The larger the carbonyl index increment, the more deteriorated the asphalt coating is, and the smaller the carbonyl index increment, the more excellent the weather resistance. Carbonyl index increment = carbonyl index (II) / carbonyl index (I) Carbonyl index (II): 1700 cm of the sample after UV irradiation －１ absorbance / 1600 cm －１ Carbonyl index (I): absorbance of the sample at 1700 cm before UV irradiation －１ absorbance / 1600 cm －１ absorbance of

[0091]

[0092] Table 3 shows that asphalt compositions obtained using asphalt modifiers containing resin A and carbon black, in which the carbon black content is 2.5% by mass or less and the mass ratio of inorganic filler (excluding carbon black) to carbon black [inorganic filler / carbon black] is 1 or less, have excellent weather resistance (Examples 1 to 6). Furthermore, in Examples 2 and 3, in which polyester resin was used as resin A, the pencil hardness was higher after UV irradiation than before UV irradiation, indicating better weather resistance. This is presumably due in part to the fact that the asphalt coating formed using an asphalt modifier containing a specific amount of polyester resin exhibited stronger interactions between the carbon black and asphalt components upon UV irradiation. In contrast, when only polyester resin was used as the asphalt modifier (Comparative Example 1), when the carbon black content in the asphalt modifier exceeded 2.5% by mass (Comparative Examples 3 and 4), and when no asphalt modifier was used (Comparative Example 5), the pencil hardness decreased after UV irradiation compared to before UV irradiation, indicating that the weather resistance of the asphalt composition was poor. In Comparative Example 2, only carbon black was used as the asphalt modifier, but the carbon black was sometimes not sufficiently dispersed in the asphalt, making it impossible to produce a uniform asphalt coating, and the rating was therefore "-".

Claims

1. An asphalt modifier containing resin A and carbon black, wherein the carbon black content is 2.5 mass% or less, and the mass ratio of inorganic filler (excluding carbon black) to carbon black [inorganic filler / carbon black] is 1 or less.

2. The asphalt modifier according to claim 1, comprising a melt-kneaded mixture of resin A and carbon black.

3. An asphalt modifier according to claim 1 or 2, having a blackness of 7 or more and 40 or less.

4. An asphalt modifier according to any one of claims 1 to 3, wherein resin A comprises at least one selected from polyester resin, ethylene-vinyl acetate copolymer resin, polyethylene resin, polypropylene resin and nylon resin.

5. The asphalt modifier according to claim 4, wherein the polyester resin comprises a polycondensate of an alcohol component, a carboxylic acid compound, and polyethylene terephthalate.

6. An asphalt modifier according to any one of claims 1 to 5, wherein the content of resin A is 97.0 mass% or more.

7. An asphalt composition comprising asphalt and the asphalt modifier according to any one of claims 1 to 6.

8. The asphalt composition according to claim 7, wherein ultraviolet rays of 300 to 400 nm are irradiated at 150 W / m ２ Carbonyl index (C Ａ ) and the carbonyl index (C Ｂ ) satisfies the following formula (1): Ａ / C Ｂ <2 (1) The carbonyl index is the carbonyl index at 1600 cm of the asphalt composition measured by Fourier transform infrared spectroscopy. －１ 1700 cm for absorbance －１ The ratio of absorbance (1700 cm －１ absorbance / 1600 cm －１ absorbance).

9. A method for producing an asphalt composition, comprising the following steps 1 and 2 in this order: Step 1: A step of mixing resin A and carbon black to obtain an asphalt modifier. Step 2: A step of mixing asphalt with the asphalt modifier obtained in Step 1. However, the asphalt modifier obtained in Step 1 contains 2.5% by mass or less of carbon black, and the mass ratio of inorganic filler (excluding carbon black) to carbon black [inorganic filler / carbon black] is 1 or less.

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