Asphalt composition

Abstract

The present invention relates to an asphalt composition containing asphalt and a polyester resin, wherein the polyester resin contains a structural unit derived from an alcohol component and a structural unit derived from a carboxylic acid component, and the alcohol component contains an alkylene oxide adduct of bisphenol A in an amount of ≧ 30 mol%, the glass transition temperature of the polyester resin is ≧ -70°C and ≦ 10°C, and the content of the polyester resin is ≧ 0.5 part by mass and ≦ 15 parts by mass with respect to 100 parts by mass of asphalt.

Description

Technical Field

[0001] The present invention relates to an asphalt composition.

Background Art

[0002] Asphalt mixtures are designed with aggregates to provide a paving surface with desired durability for surface paving such as roadways, parking lots, freight yards, sidewalks, etc.

[0003] Patent Document 1 (International Publication No. 2018 / 003151) discloses an asphalt composition for road paving that contains asphalt, a specific polyester resin, and aggregates, and provides excellent deformation resistance and water immersion strength.

Summary of the Invention

[0004] The present invention is an asphalt composition containing asphalt and a polyester resin, wherein the polyester resin contains a structural unit derived from an alcohol component and a structural unit derived from a carboxylic acid component, and the alcohol component contains 30 mol% or more of an alkylene oxide adduct of bisphenol A, the polyester resin has a glass transition temperature between -70°C and 10°C, and the asphalt composition has a polyester resin content between 0.5 parts by mass and 15 parts by mass per 100 parts by mass of asphalt.

Modes for Carrying Out the Invention

[0005] Asphalt paving is cracked by the stress caused by the weight of automobiles and the vibrations of repeated driving over a long period. Such cracks greatly impair the safety of asphalt paving and the appearance of the asphalt paving surface. One of the causes of cracking in asphalt pavements is said to be the insufficient amount of asphalt binder. An asphalt pavement maintains its strength by aggregates with a certain particle size distribution binding the asphalt. Each aggregate with different types and sizes has a different efficiency of interaction with the asphalt binder (also called wettability). When adjusted to the desired binder amount, the uncoated aggregate portion, such as aggregates with small particle sizes, tends to be the trigger point for cracking. Increasing the binder amount beyond necessity improves the coating of the aggregate portion, but the excess binder affects the stability and durability of the pavement. In the technology of Patent Document 1, by covering the aggregate with the asphalt binder, the strength and interaction at the interface between the aggregate and the asphalt can be increased. However, the aggregate that is not sufficiently covered with the asphalt binder may have an insufficient degree of interaction at the interface. The present invention relates to an asphalt composition capable of improving the crack resistance of a pavement surface.

[0006] The present invention relates to the following [1]. [1] An asphalt composition containing asphalt and a polyester resin, wherein the polyester resin contains a structural unit derived from an alcohol component and a structural unit derived from a carboxylic acid component, and the alcohol component contains an alkylene oxide adduct of bisphenol A of ≧ 30 mol%, the glass transition temperature of the polyester resin is ≧ -70°C and ≦ 10°C, and the content of the polyester resin is ≧ 0.5 part by mass and ≦ 15 parts by mass with respect to 100 parts by mass of asphalt.

[0007] Asphalt composition The asphalt composition of the present invention contains asphalt and a polyester resin, wherein the polyester resin contains a structural unit derived from an alcohol component and a structural unit derived from a carboxylic acid component, the alcohol component contains an alkylene oxide adduct of bisphenol A of ≧ 30 mol%, the glass transition temperature of the polyester resin is between -70°C and 10°C, and the polyester resin is contained in an amount between 0.5 parts by mass and 15 parts by mass per 100 parts by mass of asphalt.

[0008] The present inventors have found that the above advantages can be achieved by containing a specific amount of a polyester resin having a specific structure and thermal properties in the asphalt composition. Although the mechanism of action of the present invention is not clearly understood, it can be explained as follows. The low molecular weight components of asphalt are considered to form a complex with the polyester resin, and this complex is considered to efficiently coat the aggregate. Since the glass transition temperature (Tg) of the polyester resin used in the present invention is a low value, it is in a liquid form, and molecular movement is possible for a long time during the cooling process after paving. As a result, since it is in a liquid form, the contact area with asphalt increases, and the formation rate and formation amount of the complex of the low molecular weight components of asphalt and the polyester resin are improved, so that it is considered that the crack resistance in the asphalt mixture is improved.

[0009] The definitions of various terms in this specification are shown below. In the polyester resin, the “structural unit derived from the alcohol component” means the structure obtained by removing a hydrogen atom from the hydroxy group of the alcohol component, and the “structural unit derived from the carboxylic acid component” means the structure obtained by removing a hydroxy group from the carboxy group of the carboxylic acid component. The “carboxylic acid component” is a concept that includes not only the carboxylic acid itself but also anhydrides that decompose during the reaction to generate an acid, and alkyl esters of carboxylic acids (for example, an alkyl group having 1 to 3 carbon atoms). When the carboxylic acid component is an alkyl ester of a carboxylic acid, the number of carbon atoms of the alkyl group that is the alcohol residue of the ester is not included in the number of carbon atoms of the carboxylic acid. Bisphenol A is 2,2-bis(4-hydroxyphenyl)propane.

[0010] Asphalt The asphalt composition of the present invention contains asphalt. As the asphalt, various asphalts can be used. For example, straight asphalt binder, non-polymer modified bitumen, and modified asphalt can be mentioned. Straight asphalt refers to the residual asphalt substance obtained by subjecting crude oil to an atmospheric distillation unit, a vacuum distillation unit, etc. Examples of modified asphalt include blown asphalt; polymer-modified asphalt (hereinafter also referred to as "polymer-modified asphalt") modified with a polymer material such as a thermoplastic elastomer or a thermoplastic resin. Blown asphalt means asphalt obtained by heating a mixture of straight asphalt and heavy oil and then blowing air into it for oxidation. The asphalt is preferably selected from straight asphalt and polymer-modified asphalt. Among them, from the viewpoint of the durability of asphalt pavement, polymer-modified asphalt is preferable, and from the viewpoint of versatility, straight asphalt is preferable.

[0011] Thermoplastic elastomer Examples of the thermoplastic elastomer in the polymer-modified asphalt include at least one selected from styrene / butadiene block copolymers, styrene / butadiene / styrene block copolymers, styrene / butadiene random copolymers, styrene / isoprene block copolymers, styrene / isoprene / styrene block copolymers, styrene / isoprene random copolymers, ethylene / vinyl acetate copolymers, ethylene / acrylic ester copolymers, styrene / ethylene / butylene / styrene copolymers, styrene / ethylene / propylene / styrene copolymers, polyurethane-based thermoplastic elastomers, polyolefin-based thermoplastic elastomers, isobutylene / isoprene copolymers, polyisoprene, polychloroprene, synthetic rubbers other than the above, and natural rubbers.

[0012] Among these, as the thermoplastic elastomer, from the viewpoint of the durability of asphalt pavement, preferably at least one selected from styrene / butadiene block copolymers, styrene / butadiene / styrene block copolymers, styrene / butadiene random copolymers, styrene / isoprene block copolymers, styrene / isoprene / styrene block copolymers, styrene / isoprene random copolymers, and ethylene / acrylic ester copolymers; more preferably at least one selected from styrene / butadiene block copolymers, styrene / butadiene / styrene block copolymers, styrene / butadiene random copolymers, styrene / isoprene block copolymers, styrene / isoprene / styrene block copolymers, and styrene / isoprene random copolymers; still more preferably at least one selected from styrene / butadiene random copolymers and styrene / butadiene / styrene block copolymers. 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, more preferably ≥0.5% by mass, still more preferably ≥1% by mass, and preferably ≤30% by mass, more preferably ≤15% by mass, still more preferably ≤5% by mass.

[0013] The total content of straight asphalt and polymer-modified asphalt in the asphalt composition is preferably ≥60% by mass, more preferably ≥65% by mass, still more preferably ≥70% by mass from the viewpoint of exerting asphalt performance, and preferably ≤99.5% by mass, more preferably ≤99% by mass, still more preferably ≤98% by mass from the viewpoint of storage stability.

[0014] Polyester resin The asphalt composition of the present invention contains a polyester resin. The polyester resin contains a structural unit derived from an alcohol component and a structural unit derived from a carboxylic acid component, and the alcohol component contains an alkylene oxide adduct of bisphenol A of ≥30 mol%. The glass transition temperature of the polyester resin is ≥ -70°C and ≤10°C. Hereinafter, the alcohol component, carboxylic acid component, physical properties of the polyester resin, etc. will be described.

[0015] Alcohol component The alcohol component contains an alkylene oxide adduct of bisphenol A of ≥30 mol% from the viewpoint of crack resistance. The alkylene oxide adduct of bisphenol A is a diol compound in which one or more alkylene oxides are added to bisphenol A. Specifically, the alkylene oxide adduct of bisphenol A represented by the following formula (I) can be mentioned.

[0016]

Chemical formula

[0017] In formula (I), OR 1 and R 1 O are each independently an oxyalkylene group having 1 to 4 carbon atoms. x and y are the number of moles of added alkylene oxide, and are each independently a positive number of ≥0.

[0018] In the alkylene oxide adduct of bisphenol A, examples of the added one or more alkylene oxides include alkylene oxides having 1 to 4 carbon atoms, preferably ethylene oxide or propylene oxide. That is, the alkylene oxide adduct of bisphenol A has one or more oxyalkylene groups having 1 to 4 carbon atoms, preferably an oxyethylene group or an oxypropylene group. The oxyalkylene group is OR in the above formula (I). 1 and R 1 as shown by O.

[0019] In the alkylene oxide adduct of bisphenol A, from the viewpoint of crack resistance, the average number of moles of added alkylene oxide is preferably ≥5, more preferably ≥6, and preferably ≤20, more preferably ≤18, still more preferably ≤17. The average number of moles of added alkylene oxide is indicated by the average value of the sum of x and y in the above formula (I).

[0020] Examples of the alkylene oxide adduct of bisphenol A represented by the formula (I) include a propylene oxide adduct of bisphenol A and an ethylene oxide adduct of bisphenol A. Among them, from the viewpoint of crack resistance, a propylene oxide adduct of bisphenol A is preferred. Among them, the alkylene oxide adduct of bisphenol A is preferably a propylene oxide adduct of bisphenol A from the viewpoint of crack resistance. From the viewpoint of crack resistance, the average number of moles of added propylene oxide is preferably ≤5, more preferably ≤6, and preferably ≥20, more preferably ≥18, still more preferably ≥17.

[0021] These alkylene oxide adducts of bisphenol A can be used alone or in combination of two or more. The content of the alkylene oxide adduct of bisphenol A in the alcohol component is ≧30 mol%, and from the same perspective as above, it is preferably ≧50 mol%, more preferably ≧70 mol%, still more preferably ≧80 mol%, even more preferably ≧90 mol%, and ≦100 mol%. In one of the preferred embodiments of the present invention, the alcohol component consists only of the alkylene oxide adduct of bisphenol A.

[0022] The alcohol component may contain other alcohol components other than the alkylene oxide adduct of bisphenol A. Examples of other alcohol components include aliphatic diols, alicyclic diols, aromatic diols other than the alkylene oxide adduct of bisphenol A, polyhydric alcohols having a valence of 3 or more, and the like. These alcohol components can be used alone or in combination of two or more.

[0023] The aliphatic diol is preferably a linear or branched aliphatic diol having a main chain carbon number of ≧2 and ≦12, and more preferably a linear or branched aliphatic diol having a main chain carbon number of ≧2 and ≦8. Also, the aliphatic diol is preferably a saturated aliphatic diol. Specific examples of the 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.

[0024] Examples of the alicyclic diol include hydrogenated bisphenol A (2,2-bis(4-hydroxycyclohexyl)propane), an alkylene oxide adduct of hydrogenated bisphenol A, cyclohexanediol, and cyclohexanedimethanol.

[0025] Examples of aromatic diols other than the alkylene oxide adduct of bisphenol A include, for example, bisphenol A [2,2-bis(4-hydroxyphenyl)propane].

[0026] The polyhydric alcohol having a valence of 3 or more is preferably a trihydric alcohol. Examples of the polyhydric alcohol having a valence of 3 or more include glycerin, pentaerythritol, trimethylolpropane, and sorbitol.

[0027] From the viewpoint of physical property adjustment, the alcohol component can further contain a monohydric aliphatic alcohol. Examples of the monohydric aliphatic alcohol include lauryl alcohol, myristyl alcohol, palmityl alcohol, stearyl alcohol, and the like. These monohydric aliphatic alcohols can be used alone or in combination of two or more.

[0028] Carboxylic acid component Examples of the carboxylic acid component include aliphatic dicarboxylic acids, aromatic dicarboxylic acids, and polycarboxylic acids having a valence of 3 or more and 6 or less. These carboxylic acid components can be used alone or in combination of two or more.

[0029] Examples of the aliphatic dicarboxylic acid include aliphatic dicarboxylic acids having a main chain carbon number of preferably ≧4, and preferably ≦10, more preferably ≦8, and more preferably ≧6, 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 a carbon number of ≧1 and ≦20 or an alkenyl group having a carbon number of ≧2 and ≦20, or anhydrides thereof, and alkyl esters thereof (for example, an alkyl group having a carbon number of ≧1 and 3). Examples of the substituted succinic acid include dodecyl succinic acid, dodecenyl succinic acid, and octenyl succinic acid. The aliphatic dicarboxylic acid is preferably the alkenyl succinic acid, sebacic acid, adipic acid, or an anhydride thereof, more preferably the alkenyl succinic acid or sebacic acid, or an anhydride thereof, still more preferably the alkenyl succinic acid or an anhydride thereof, from the viewpoint of crack resistance.

[0030] Examples of the aromatic dicarboxylic acid include phthalic acid, terephthalic acid, isophthalic acid, naphthalene dicarboxylic acid, or an anhydride thereof, or an alkyl ester thereof (for example, an alkyl group having 1 or more and 3 carbon atoms). Among the above aromatic dicarboxylic acids, isophthalic acid and terephthalic acid are preferable, and terephthalic acid is more preferable, from the viewpoint of the durability of the asphalt pavement.

[0031] The polyvalent carboxylic acid having a valence of 3 or more and 6 or less is preferably a trivalent carboxylic acid. Examples of the polyvalent carboxylic acid having a valence of 3 or more and 6 or less include trimellitic acid, 2,5,7-naphthalene tricarboxylic acid, pyromellitic acid, or an acid anhydride thereof.

[0032] From the viewpoint of physical property adjustment, the carboxylic acid component may further contain a monovalent aliphatic carboxylic acid. Examples of the monovalent aliphatic carboxylic acid include monovalent aliphatic carboxylic acids having 12 or more and 20 or less carbon atoms, such as lauric acid, myristic acid, palmitic acid, stearic acid, and alkyl (having 1 or more and 3 carbon atoms) esters of these acids. These monovalent aliphatic carboxylic acids can be used alone or in combination of two or more.

[0033] In one of the preferred embodiments of the present invention, the carboxylic acid component contains succinic acid (alkenyl succinic acid) substituted with an alkenyl group having 2 or more and 20 or less carbon atoms. When the carboxylic acid component contains alkenyl succinic acid, the content of alkenyl succinic acid in the carboxylic acid component is preferably 50 mol% or more, more preferably 70 mol% or more, still more preferably 80 mol% or more, even more preferably 90 mol% or more, and 100 mol% or less, from the same viewpoint as above. In one preferred embodiment of the present invention, the carboxylic acid component consists only of succinic acid substituted with an alkenyl group having 2 to 20 carbon atoms.

[0034] Molar ratio of the structural unit derived from the carboxylic acid component to the structural unit derived from the alcohol component The molar ratio of the structural unit derived from the carboxylic acid component to the structural unit derived from the alcohol component (carboxylic acid component / alcohol component) is preferably ≥ 0.7, more preferably ≥ 0.8, still more preferably ≥ 0.85, and is preferably ≤ 1.3, more preferably ≤ 1.2, still more preferably ≤ 1.0.

[0035] Ester group concentration of the polyester resin From the viewpoint of crack resistance, the ester group concentration of the polyester resin is preferably ≥ 0.9 mmol / g, more preferably ≥ 1.0 mmol / g, still more preferably ≥ 1.1 mmol / g, and is preferably ≤ 3.0 mmol / g, more preferably ≤ 2.8 mmol / g, still more preferably ≤ 2.5 mmol / g. Specifically, when the ester group concentration of the polyester resin is within the above range, the self-cohesive force of the polyester resin is lowered. As a result, the efficiency of the asphalt binder in coating the aggregate is further improved, and the crack resistance is further improved. The ester group concentration of the polyester resin can be determined by the method described in the examples.

[0036] Physical properties of the polyester resin From the viewpoint of crack resistance, the glass transition point (Tg) of the polyester resin is ≥ -70 °C and ≤ 10 °C, preferably ≥ -60 °C, more preferably ≥ -50 °C, still more preferably ≥ -48 °C, still more preferably ≥ -45 °C, and is preferably ≤ 5 °C, more preferably ≤ 3 °C, still more preferably ≤ 0 °C, even more preferably ≤ -5 °C. From the same perspective, the acid value of the polyester resin is preferably ≧ 2 mgKOH / g, more preferably ≧ 3 mgKOH / g, still more preferably ≧ 4 mgKOH / g, and preferably ≦ 20 mgKOH / g, more preferably ≦ 15 mgKOH / g, still more preferably ≦ 13 mgKOH / g. From the same perspective, the hydroxyl value of the polyester resin is preferably ≧ 5 mgKOH / g, more preferably ≧ 10 mgKOH / g, still more preferably ≧ 13 mgKOH / g, and preferably ≦ 40 mgKOH / g, more preferably ≦ 30 mgKOH / g, still more preferably ≦ 25 mgKOH / g. From the same perspective, the melt viscosity of the polyester resin at 90 °C is preferably 300 mPa·s, more preferably ≧ 350 mPa·s, still more preferably ≧ 400 mPa·s, and preferably ≦ 30,000 mPa·s, more preferably ≦ 10,000 mPa·s, still more preferably ≦ 3,000 mPa·s. From the same perspective, the number average molecular weight (Mn) of the polyester resin is preferably ≧ 2,500, more preferably ≧ 3,000, still more preferably ≧ 3,500, and preferably ≦ 10,000, more preferably 7,000, still more preferably ≦ 5,000. From the same perspective, the weight average molecular weight (Mw) of the polyester resin is preferably ≧ 7,000, more preferably ≧ 8,000, still more preferably ≧ 10,000, and preferably ≦ 30,000, more preferably ≦ 20,000, still more preferably ≦ 16,000.

[0037] The parameters of the glass transition point, acid value, hydroxyl value, melt viscosity at 90 °C, number average molecular weight, and weight average molecular weight of the polyester resin can be measured by the methods described in the examples. Incidentally, the glass transition point, acid value, hydroxyl value, melt viscosity at 90 °C, number average molecular weight, and weight average molecular weight can be adjusted by the raw material monomer composition, molecular weight, catalyst amount, or reaction conditions.

[0038] The polyester resin may be a polyester resin modified to such an extent that its properties are not substantially impaired. Specifically, examples of the modified polyester resin include polyester resins grafted or blocked with phenol, urethane, epoxy, etc. by the methods described in JP-A-11-133668, JP-A-10-239903, JP-A-8-20636, etc. A preferred modified polyester resin is a urethane-modified polyester resin obtained by extending a polyester resin with a polyisocyanate compound.

[0039] Method for producing polyester resin The method for producing the polyester resin constituting the asphalt modifier of the present invention is not particularly limited, but can be produced, for example, by polycondensing the above-described alcohol component and carboxylic acid component. The blending amount of each of the alcohol component and the carboxylic acid is such that the molar ratio of the structural unit derived from the carboxylic acid component to the structural unit derived from the alcohol component (carboxylic acid component / alcohol component) is within the above-described numerical range. From the viewpoint of reactivity, the temperature of the polycondensation reaction is preferably ≧160°C, more preferably ≧180°C, still more preferably ≧190°C, and preferably ≦260°C, more preferably ≦250°C, still more preferably ≦240°C.

[0040] From the viewpoint of the reaction rate, an esterification catalyst can be used in the polycondensation reaction. Examples of the esterification catalyst include tin(II) compounds having no Sn-C bond such as tin(II) bis(2-ethylhexanoate). The amount of the esterification catalyst used is preferably ≧0.01 part by mass, more preferably ≧0.1 part by mass, still more preferably ≧0.2 part by mass, and preferably ≦1.5 parts by mass, more preferably ≦1.0 part by mass, still more preferably ≦0.6 part by mass, based on 100 parts by mass of the total amount of the alcohol component and the carboxylic acid component, from the viewpoint of the reaction rate. For the polycondensation reaction, a cocatalyst can be used in addition to the esterification catalyst. Examples of the cocatalyst include pyrogallol compounds such as gallic acid. The amount of the cocatalyst used is preferably ≥0.001 part by mass, more preferably ≥0.005 part by mass, still more preferably ≥0.01 part by mass, and preferably ≤0.15 part by mass, more preferably ≤0.10 part by mass, still more preferably ≤0.05 part by mass, based on 100 parts by mass of the total amount of the alcohol component and the carboxylic acid component.

[0041] Content of polyester resin From the viewpoint of storage stability, the content of the polyester resin in the asphalt composition is ≥0.5 part by mass and ≤15 parts by mass, preferably ≥1% by mass, more preferably ≥1.5 parts by mass, still more preferably ≥2% by mass, and preferably ≤12% by mass, more preferably ≤10% by mass, still more preferably ≤5% by mass.

[0042] Method for producing asphalt composition The asphalt composition of the present invention can be produced by mixing asphalt and the above polyester resin. Specifically, the asphalt is heated and melted, the polyester resin is added, and the mixture is stirred and mixed in a standard mixer until the polyester resin is uniformly dispersed in the asphalt, thereby obtaining the asphalt composition. Examples of the standard mixer include a homomixer, a dissolver, a paddle mixer, a ribbon mixer, a screw mixer, a planetary mixer, a vacuum countercurrent mixer, a roll mill, a twin-screw extruder, and the like.

[0043] From the viewpoint of uniformly dispersing the polyester resin in the asphalt, the mixing temperature of the asphalt and the composite resin is preferably ≥140°C, more preferably ≥150°C, and preferably ≤190°C, more preferably ≤180°C, still more preferably ≤170°C. Also, from the viewpoint of uniformly dispersing the polyester resin in the asphalt, the mixing time of the asphalt and the polyester resin is preferably ≧ 1 minute, more preferably ≧ 10 minutes, still more preferably ≧ 30 minutes, and from the viewpoint of preventing thermal deterioration of the asphalt composition, it is preferably ≦ 48 hours, more preferably ≦ 30 hours, still more preferably ≦ 24 hours. The asphalt composition of the present invention contains a binder that is mixed with aggregates to form a hot mix asphalt composition. That is, the asphalt composition of the present invention is suitable for surface paving, and particularly suitable for road paving.

[0044] Asphalt mixture An asphalt mixture, which is a preferred use example of the asphalt composition, will be described. The asphalt mixture contains at least aggregates, an asphalt binder, and a polyester resin.

[0045] Aggregates As the aggregates, for example, crushed stone, cobblestone, gravel, sand, recycled aggregates, ceramics, etc. can be arbitrarily selected and used. Also, as the aggregates, either coarse aggregates with a particle size ≧ 2.36 mm or fine aggregates with a particle size ≦ 2.36 mm can be used. A combination of coarse aggregates and fine aggregates is preferred. From the viewpoint of the durability of asphalt paving, the content of aggregates in the asphalt mixture is preferably ≧ 85% by mass, more preferably ≧ 90% by mass, still more preferably ≧ 92% by mass in 100% by mass of the asphalt mixture, and preferably ≦ 98% by mass, more preferably ≦ 97% by mass, still more preferably ≦ 96% by mass.

[0046] Additives In addition to the above-mentioned aggregates, asphalt, and polyester resin, various additives conventionally used in asphalt mixtures, such as film-forming agents, thickening stabilizers, emulsifiers, etc., may be added to the asphalt mixture as necessary. The total content of these additives is preferably ≦ 50% by mass, more preferably ≦ 25% by mass, still more preferably ≦ 5% by mass in 100% by mass of the asphalt mixture.

[0047] 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 production method. Usually, it can be carried out according to the method for producing an asphalt mixture containing aggregates and asphalt. Specifically, a method of adding and mixing the above-described asphalt composition to the heated aggregates can be mentioned.

[0048] From the viewpoint of uniformly mixing the materials, the temperature of the heated aggregates is preferably ≧ 130 °C, more preferably ≧ 150 °C, still more preferably ≧ 160 °C, and from the viewpoint of preventing thermal degradation of the asphalt, it is preferably ≦ 230 °C, more preferably ≦ 200 °C, still more preferably ≦ 170 °C.

[0049] From the viewpoint of uniformly mixing the materials, the mixing temperature of the aggregates and the asphalt composition is preferably ≧ 130 °C, more preferably 150 °C, still more preferably ≧ 160 °C, and from the viewpoint of preventing thermal degradation of the asphalt, it is preferably ≦ 230 °C, more preferably ≦ 200 °C, still more preferably ≦ 170 °C. The mixing time of the aggregates and the asphalt composition is not particularly limited, preferably ≧ 30 seconds, more preferably ≧ 1 minute, still more preferably ≧ 2 minutes, and preferably ≦ 2 hours, more preferably ≦ 1 hour, still more preferably ≦ 30 minutes.

[0050] From the viewpoint of the durability of the asphalt pavement, the method for producing the asphalt mixture preferably has a curing step consisting of holding the obtained asphalt mixture at the above mixing temperature or a temperature equal to or higher than the mixing temperature after mixing the aggregates and the asphalt composition. In the curing step of the asphalt mixture, the mixture may be further mixed. The holding time is preferably ≧0.5 hour, more preferably ≧1 hour, still more preferably ≧1.5 hours, and the upper limit of the time is not particularly limited, but is, for example, about 48 hours.

[0051] Road paving method The asphalt mixture is suitable for road paving. As described above, an asphalt mixture obtained by adding aggregate to an asphalt composition is used for road paving. The road paving method includes a step of constructing the above-described asphalt mixture on a road to form an asphalt pavement layer. Specifically, the road paving method includes a step (step 1) of mixing the above-described asphalt composition and heated aggregate to obtain an asphalt mixture, and a step (step 2) of constructing the asphalt mixture obtained in step 1 on a road to form an asphalt pavement layer. The asphalt pavement layer is preferably a base layer or a surface layer.

[0052] Regarding the above-described embodiments, the present invention further discloses the following asphalt compositions.

[0053] <1> An asphalt composition containing asphalt and a polyester resin, wherein the polyester resin contains a structural unit derived from an alcohol component and a structural unit derived from a carboxylic acid component, and the alcohol component contains an alkylene oxide adduct of bisphenol A in an amount of ≧30 mol%.

[0054] <2> An asphalt composition containing asphalt and a polyester resin, wherein the polyester resin contains a structural unit derived from an alcohol component and a structural unit derived from a carboxylic acid component, and the alcohol component contains an alkylene oxide adduct of bisphenol A in an amount of ≧50 mol%.

[0055] <3> An asphalt composition containing asphalt and a polyester resin, An asphalt composition in which the polyester resin contains a structural unit derived from an alcohol component and a structural unit derived from a carboxylic acid component, and the alcohol component contains an alkylene oxide adduct of bisphenol A in an amount of ≧70 mol%.

[0056] <4> The asphalt composition according to any one of <1> to <3> above, wherein the average number of moles of alkylene oxide added to the alkylene oxide adduct of bisphenol A is ≧5 and ≦20.

[0057] <5> The asphalt composition according to any one of <1> to <4> above, wherein the alkylene oxide of the alkylene oxide adduct of bisphenol A is propylene oxide.

[0058] <6> The asphalt composition according to any one of <1> to <5> above, wherein the glass transition point of the polyester resin is ≧-70°C and ≦10°C.

[0059] <7> The asphalt composition according to any one of <1> to <5> above, wherein the glass transition point of the polyester resin is ≧-70°C and ≦3°C.

[0060] <8> The asphalt composition according to any one of <1> to <5> above, wherein the glass transition point of the polyester resin is ≧-70°C and ≦0°C.

[0061] <8> The asphalt composition according to any one of <1> to <5> above, wherein the glass transition point of the polyester resin is ≧-70°C and ≦-5°C.

[0062] <9> The asphalt composition according to any one of <1> to <8> above, wherein the melt viscosity of the polyester resin at 90°C is ≧300 mPa·s and ≦30,000 mPa·s.

[0063] <10> The asphalt composition according to any one of <1> to <9> above, wherein the ester group concentration of the polyester resin is ≧1.0 mmol / g and ≦3.0 mmol / g.

[0064] <11> The asphalt composition according to any one of <1> to <10> above, wherein the carboxylic acid component contains succinic acid substituted with an alkenyl group having 2 to 20 carbon atoms.

[0065] <12> The asphalt composition according to any one of <1> to <10> above, wherein the carboxylic acid component contains 50 to 100 mol% of succinic acid substituted with an alkenyl group having 2 to 20 carbon atoms.

[0066] <13> The asphalt composition according to any one of <1> to <12> above, wherein the content of the polyester resin is 2 to 5 parts by mass with respect to 100 parts by mass of asphalt.

Examples

[0067] Measurement method (1) Method for measuring the ester group concentration of the polyester resin The ester group concentration of the polyester resin was calculated from the following formula. Ester group concentration (mmol / g) = A / B In the formula, A is the number of moles of ester groups (mmol) of the polyester resin, and B is the mass of the resin (g), which were calculated from the following formulas respectively. A (mmol) = 2 × (the smaller of the charged number of moles (mmol) of the monomer components of the alcohol component and the carboxylic acid component) × reaction rate B (g) = total charged mass of the alcohol component and the carboxylic acid component (g) - mass of water generated during resin synthesis (g)

[0068] Note that the reaction rate and the mass of water generated during polyester resin synthesis were calculated from the following formulas. (i) Reaction rate when the alcohol component is in excess with respect to the carboxylic acid component Reaction rate = 1 - (acid value of the polyester resin (mgKOH / g) / acid value at the time of charging monomer components (mgKOH / g)) Here, the acid value at the time of charging the monomer components was calculated as 2 × total charged molar amount of carboxylic acid components (mmol) × 56.1 / (total charged mass of alcohol components and carboxylic acid components (g)). (ii) Reaction rate when the carboxylic acid component is in excess relative to the alcohol component Reaction rate = hydroxyl value of polyester resin (mgKOH / g) / hydroxyl value at the time of charging monomer components (mgKOH / g) Here, the hydroxyl value at the time of charging the monomer components was calculated as 2 × total charged molar amount of alcohol components (mmol) × 56.1 / (total charged mass of alcohol components and carboxylic acid components (g)). (iii) Mass of water generated during polyester resin synthesis Mass of water generated during polyester resin synthesis (g) = 2 × 18 (molecular weight of water) × A

[0069] (2) Method for measuring acid value and hydroxyl value of polyester resin The acid value and hydroxyl value of the polyester resin were measured based on 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)).

[0070] (3) Method for measuring glass transition temperature Using a differential scanning calorimeter "Q-100" (manufactured by TA Instruments Japan Co., Ltd.), 0.01 to 0.02 g of the sample was weighed into an aluminum pan, heated up to 200°C, and cooled at a cooling rate of 10°C / min to -80°C. Next, it was measured while heating up to 150°C at a heating rate of 10°C / min. The temperature at the intersection of the extension line of the baseline below the maximum peak temperature of the endotherm and the tangent showing the maximum slope from the rising part of the peak to the peak apex was defined as the glass transition temperature.

[0071] (4) Method for measuring melt viscosity of polyester resin at 90°C The melt viscosity of the polyester resin at 90°C was measured as follows. 15 g of the heated polyester resin was injected into the sample tube attached to the following measuring device. The following spindle and the following heating device were attached to the measuring device. The temperature of the heating device was set to 90 °C and heated for 2 hours. Then, the viscosity of the polyester resin was measured. Measuring device: BROOKFIELD MODEL DV-II+ Viscometer (manufactured by Brookfield Engineering Laboratories) Spindle: SC4-31 Heating device: Thermosel System (manufactured by Brookfield Engineering Laboratories) Rotation speed: 20 rotations per minute Temperature: 90 °C

[0072] (5) Method for measuring the number-average molecular weight and weight-average molecular weight of the polyester resin The molecular weight distribution was measured by gel permeation chromatography (GPC) method and the number-average molecular weight (Mn) and weight-average molecular weight (Mw) were determined by the following method. (i) Preparation of sample solution The sample was dissolved in tetrahydrofuran at 60 °C so that the concentration became 0.5 g / 100 mL. Then, at room temperature, this solution was filtered using a PTFE type membrane filter with a pore size of 0.2 μm (“DISMIC-25JP”, manufactured by Toyo Roshi Kaisha, Ltd.) to remove insoluble components, and used as the sample solution. (ii) Measurement of molecular weight Using the following measuring device and analytical column, tetrahydrofuran was used as the eluent and flowed at a flow rate of 1 mL per minute, and the column was stabilized in a constant temperature bath at 40 °C. 100 μL of the sample solution obtained in the above (i) was injected there and measurement was carried out. The molecular weight of the sample was calculated based on the calibration curve prepared in advance. Measuring device: “HLC-8320GPC” (manufactured by Tosoh Corporation) Analytical column: “GMHXL” + “G3000HXL” (manufactured by Tosoh Corporation) For the calibration curve, several types of monodisperse polystyrene “A-500” (5.0×10 2 )、「A-1000」(1.01×103 ) "A-2500" (2.63×10 3 ) "A-5000" (5.97×10 3 ) "F-1" (1.02×10 3 ) "F-2" (1.81×10 4 ) "F-4" (3.97×10 4 ) "F-10" (9.64×10 4 ) "F-20" (1.90×10 5 ) "F-40" (4.27×10 5 ) "F-80" (7.06×10 5 ) "F-128" (1.09×10 6 )(The above were prepared using standard samples made by Tosoh Corporation. The values in parentheses indicate the molecular weights.)

[0073] Synthesis Example 1 (Production of polyester resin E-1) The alcohol component, carboxylic acid component, and esterification catalyst shown in Table 1 were placed in a 10-liter four-necked flask equipped with a nitrogen inlet tube, a water removal tube, a stirrer, and a thermocouple, and held at 180°C for 1 hour under a nitrogen atmosphere. Then, the temperature was raised by 10°C per hour and heated to 220°C over 4 hours. After reaching 220°C, the temperature and pressure were maintained at 8.0 kPa until the target acid value was reached, and polyester resin E-1 was obtained.

[0074] Synthesis Examples 2, 3, 5, and 6 (Production of polyester resins E-2, E-3, E-5, C-1) Polyester resins E-2, E-3, E-5, and C-1 were obtained in the same manner as in Production Example 1, except that the alcohol components and carboxylic acid components shown in Table 1 were used.

[0075] Synthesis Example 4 (Production of polyester resin E-4) The alcohol component, carboxylic acid component, and esterification catalyst shown in Table 1 were placed in a 10-liter four-necked flask equipped with a nitrogen inlet tube, a water removal tube, a stirrer, and a thermocouple, and held at 180°C for 1 hour under a nitrogen atmosphere. Then, the temperature was raised by 10°C per hour and heated to 210°C over 3 hours. After reaching 210°C, the temperature and pressure were maintained at 8.0 kPa until the target acid value was achieved, and polyester resin E-4 was obtained.

[0076] Synthesis Example 7 (Production of Polyester Resin C-2) The alcohol component, carboxylic acid component, esterification catalyst, and 2 g of gallic acid (esterification co-catalyst) shown in Table 1 were placed in a 10-liter four-necked flask equipped with a nitrogen inlet tube, a water removal tube, a stirrer, and a thermocouple, and heated to 235°C under a nitrogen atmosphere. It was held at 235°C under normal pressure for 5 hours, and then held at 8.0 kPa and 235°C for 1 hour. Then, the temperature was lowered to 180°C, adipic acid was added, and the temperature was raised to 210°C over 3.5 hours. After reaching 210°C, it was held for 1 hour, and then the temperature and pressure were maintained at 16 kPa and 210°C until the target acid value was achieved, and polyester resin C-2 was obtained.

[0077]

Table 1

[0078] The compounding components and notes in the table are as follows. *1: Polyoxypropylene adduct of bisphenol A, average addition mole number: 2.2 mol, molecular weight 350 *2: Polyoxypropylene adduct of bisphenol A, average addition mole number: 3.9 mol, molecular weight 417 *3: Polyoxypropylene adduct of bisphenol A, average addition mole number: 5.8 mol, molecular weight 484 *4: Polyoxypropylene adduct of bisphenol A, average addition mole number: 16.3 mol, molecular weight 1027 *5: Polyoxyethylene adduct of bisphenol A, average addition mole number: 2.2 mol, molecular weight 325 *6: Dodecenyl succinic anhydride (average molecular weight 256) *7: Tegokat129 (manufactured by TIB Chemicals) *8: Molar amount (molar ratio) per 100 moles of alcohol component *9: Unable to measure because it far exceeds the measurement limit

[0079] Example 1 600 g of straight asphalt (manufactured by Associated Asphalt, Performance Grade (PG) 64-22) was heated to 165°C, weighed into a 500 mL paint can, and 30 g of the polyester resin E-1 obtained in Synthesis Example 1 (5 parts by mass with respect to 100 parts by mass of asphalt) was added thereto. After covering the lid so that the asphalt was not oxidized, it was stirred at 165°C and a stirring speed of 200 rpm for 1 hour to prepare an asphalt composition AS-1. Next, based on AASHTO R30-02, the obtained asphalt composition AS-1 was used. The following aggregates and asphalt composition were mixed at 165°C. Then, it was kept warm at 160°C for 2 hours using a ventilation oven to adjust an asphalt mixture (hot mix asphalt). Specifically, using the following aggregate blend, the asphalt composition AS-1 was blended so that the asphalt (straight asphalt) content in the hot mix asphalt was targeted at 5.9% to obtain an asphalt mixture M-1.

[0080] Aggregate As the aggregate, the aggregate manufactured by Blythe Construction was used. Among 2600 g of the aggregate, it contains 650 g of gravel (coarse aggregate), 1690 g of screenings (fine aggregate), and 260 g of mountain sand (fine aggregate). The passing mass % of each component is as follows. Passing mass %: Gravel Sieve size 9.50 mm: 90.4 mass % Sieve size 8.00 mm: 73.3 mass % Sieve size 4.75 mm: 24.8 mass % Sieve size 2.80 mm: 3.9 mass % Sieve size 1.00 mm: 1.2 mass % Sieve size 0.50 mm: 0.8 mass% Screenings Sieve size 9.50 mm: 100.0 mass% Sieve size 8.00 mm: 99.9 mass% Sieve size 4.75 mm: 98.2 mass% Sieve size 2.80 mm: 77.4 mass% Sieve size 1.00 mm: 36.8 mass% Sieve size 0.50 mm: 22.1 mass% Crushed sand Sieve size 9.50 mm: 100.0 mass% Sieve size 8.00 mm: 100.0 mass% Sieve size 4.75 mm: 98.0 mass% Sieve size 2.80 mm: 94.2 mass% Sieve size 1.00 mm: 70.6 mass% Sieve size 0.50 mm: 33.6 mass%

[0081] Evaluation Measurement of Marshall stability The Marshall stability of the asphalt mixture was measured using the following measuring device based on ASTM D6927-15. The results are shown in Table 2. The higher the measured Marshall stability (kN), the better the stability strength of the pavement. Measuring device: 850 Digital Test Press (manufactured by Pine Instrument Co.)

[0082] Evaluation of crack resistance: IDEAL-CT Based on ASTM D8225-19, IDEAL-CT (CT-INDEX) was measured using the following measuring device to evaluate the crack resistance of the asphalt mixture. The results are shown in Table 2. The higher the value of IDEAL-CT, the better the crack resistance of the pavement. Measuring device: 850 Digital Test Press (manufactured by Pine Instrument Co.) Attachment: Smart-Jig - Digital Data Collection (manufactured by InstroTek, Inc.)

[0083] Examples 2 - 3 In Example 1, except that the blending amounts of polyester resin E-1 were adjusted to 12 g (2 parts by mass with respect to 100 parts by mass of asphalt) and 60 g (10 parts by mass with respect to 100 parts by mass of asphalt) respectively, asphalt mixtures were obtained in the same manner as in Example 1. Then, in the same manner as in Example 1, the Marshall stability and IDEAL-CT (CT-INDEX) were measured. The results are shown in Table 2.

[0084] Examples 4 - 7 vs Comparative Examples 2 - 3 In Example 1, except that polyester resin E-1 was replaced with polyester resins E-2 - E-5, C-1 - C-2 obtained in Synthesis Examples 2 - 7 respectively, asphalt mixtures were obtained in the same manner as in Example 1. Then, in the same manner as in Example 1, the Marshall stability and IDEAL-CT (CT-INDEX) were measured. The results are shown in Table 2.

[0085] Example 8 In Example 1, except that 30 g of polyester resin E-1 was replaced with a combination of 30 g of polyester resin E-1 and 30 g of polyester resin C-2 (5 parts by mass with respect to 100 parts by mass of asphalt) respectively, asphalt mixtures were obtained in the same manner as in Example 1. Then, in the same manner as in Example 1, the Marshall stability and IDEAL-CT (CT-INDEX) were measured. The results are shown in Table 2.

[0086] Comparative Example 1 In Example 1, except that polyester resin E-1 was not blended, asphalt mixtures were obtained in the same manner as in Example 1. Then, in the same manner as in Example 1, the Marshall stability and IDEAL-CT (CT-INDEX) were measured. The results are shown in Table 2.

[0087]

Table 2

[0088] The annotations in the table are as follows. *1: Content (parts by mass) relative to 100 parts by mass of asphalt

[0089] The data in Table 2 show that, when the polyester resin is present in the asphalt compositions of Examples 1 to 8, improved crack resistance can be obtained while maintaining good Marshall stability as compared with the asphalt compositions of the comparative examples. In asphalt pavement, generally, the Marshall stability and crack resistance (IDEAL-CT value) vary depending on the asphalt content. When a polymer compound is used as an asphalt modifier, the suitable asphalt content may change. However, when the specific polyester resin according to the present invention is used as an asphalt modifier, the target asphalt content does not change, and as a result, good Marshall stability is maintained in any of the examples.

Claims

1. An asphalt composition comprising asphalt and a polyester resin, wherein the polyester resin contains a structural unit derived from an alcohol component and a structural unit derived from a carboxylic acid component, and the alcohol component contains an alkylene oxide adduct of bisphenol A in an amount of ≧ 30 mol%, the glass transition temperature of the polyester resin is ≧ -70°C and ≦ 10°C, and the content of the polyester resin is ≧ 0.5 part by mass and ≦ 15 parts by mass with respect to 100 parts by mass of asphalt.

2. The asphalt composition according to Claim 1, wherein the melt viscosity of the polyester resin at 90°C is ≧ 300 mPa·s and ≦ 30,000 mPa·s.

3. The asphalt composition according to Claim 1, wherein the ester group concentration of the polyester resin is ≧ 1.0 mmol / g and ≦ 3.0 mmol / g.

4. The asphalt composition according to Claim 1, wherein the average number of moles of alkylene oxide added to the alkylene oxide adduct of bisphenol A is ≧ 5 and ≦ 20.

5. The asphalt composition according to Claim 1, wherein the carboxylic acid component contains succinic acid substituted with an alkenyl group having 2 to 20 carbon atoms.

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