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 invention is asphalt to Regarding compositions. [Background technology]

[0002] Asphalt mixtures are designed with aggregates to provide a paved surface with the desired durability for use in surface paving of highways, parking lots, freight yards, sidewalks, and the like.

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

[0004] The present invention relates to an asphalt composition comprising asphalt and polyester resin, The polyester resin comprises structural units derived from an alcohol component and structural units derived from a carboxylic acid component, wherein 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. The asphalt composition contains polyester resin in an amount 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 pavement develops cracks due to the weight of vehicles and the stress caused by repeated vibrations from driving over long periods. Such cracks significantly impair the safety of the asphalt pavement and the aesthetic appearance of the surface. One of the causes of cracking in asphalt pavements is insufficient asphalt binder. Asphalt pavements maintain their strength through the binding of aggregates with a certain particle size distribution to the asphalt. Each type and size of aggregate has a different efficiency of interaction with the asphalt binder (also known as wettability). When the binder amount is adjusted to the desired level, aggregate portions that are not covered by the asphalt binder, such as aggregates with small particle sizes, tend to become trigger points for cracking. Increasing the binder amount more than necessary improves the coverage of the aggregate portions, but excessive binder affects the stability and durability of the pavement. In the technology described in Patent Document 1, the strength and interaction at the interface between the aggregate and asphalt can be increased by coating the aggregate with an asphalt binder. However, aggregate that is not sufficiently coated with an asphalt binder may have insufficient interaction at the interface. This invention relates to an asphalt composition that can improve the crack resistance of paved surfaces.

[0006] The present invention relates to the following [1]. [1] An asphalt composition comprising asphalt and polyester resin, The polyester resin comprises structural units derived from an alcohol component and structural units derived from a carboxylic acid component, and the alcohol component comprises 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. An asphalt composition in which the polyester resin content is ≥0.5 parts by mass and ≤15 parts by mass per 100 parts by mass of asphalt.

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

[0008] The inventors have found that the above advantages can be achieved by including a specific amount of polyester resin having a specific structure and thermal properties in the asphalt composition. Although the mechanism of action of this invention is not clearly understood, it can be explained as follows. The low molecular weight components of asphalt are thought to form a composite with polyester resin, and this composite is believed to efficiently coat the aggregate. The polyester resin used in this invention has a low glass transition temperature (Tg), resulting in a liquid state that allows for molecular motion over a long period during the cooling process after paving. As a result, the liquid state increases the contact area with the asphalt, improving the formation rate and amount of the composite between the low molecular weight components of the asphalt and the polyester resin, thereby improving the crack resistance of the asphalt mixture.

[0009] The definitions of various terms used in this specification are shown below. In polyester resins, "constituent units derived from alcohol components" refers to the structure obtained by removing a hydrogen atom from the hydroxyl group of an alcohol component, and "constituent units derived from carboxylic acid components" refers to the structure obtained by removing a hydroxyl group from the carboxyl group of a carboxylic acid component. The term "carboxylic acid component" is a concept that includes not only the carboxylic acid itself, but also the anhydride that decomposes during the reaction to produce acid, and alkyl esters of carboxylic acids (for example, alkyl groups with 1 and 3 carbon atoms). When the carboxylic acid component is an alkyl ester of a carboxylic acid, the number of carbon atoms in the alkyl group, which is the alcohol residue of the ester, is not included in the number of carbon atoms of the carboxylic acid. Bisphenol A is 2,2-bis(4-hydroxyphenyl)propane.

[0010] asphalt The asphalt composition of the present invention contains asphalt. Various types of asphalt can be used. Examples include straight asphalt binder, non-polymerized bitumen, and modified asphalt. Straight asphalt refers to the residual bituminous substance obtained by subjecting crude oil to atmospheric distillation, vacuum distillation, etc. Modified asphalts include blown asphalt and polymer-modified asphalt (hereinafter also referred to as "polymer-modified asphalt") which is modified with polymer materials such as thermoplastic elastomers and thermoplastic resins. Blown asphalt refers to asphalt obtained by heating a mixture of straight asphalt and heavy oil, and then blowing air into it to oxidize it. The asphalt is preferably selected from straight asphalt and polymer-modified asphalt. Of these, polymer-modified asphalt is preferred from the viewpoint of durability of the asphalt pavement, while straight asphalt is preferred from the viewpoint of versatility.

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

[0012] Among these, the thermoplastic elastomer is preferably at least one selected from styrene / butadiene block copolymer, styrene / butadiene / styrene block copolymer, styrene / butadiene random copolymer, styrene / isoprene block copolymer, styrene / isoprene / styrene block copolymer, styrene / isoprene random copolymer, and ethylene / acrylic acid ester copolymer, more preferably at least one selected from styrene / butadiene block copolymer, styrene / butadiene / styrene block copolymer, styrene / butadiene random copolymer, styrene / isoprene block copolymer, styrene / isoprene / styrene block copolymer, and styrene / isoprene random copolymer, and even more preferably at least one selected from styrene / butadiene random copolymer and styrene / butadiene / styrene block copolymer. From the viewpoint of durability of asphalt pavement, the content of thermoplastic elastomer in polymer-modified asphalt is preferably ≥0.1% by mass, more preferably ≥0.5% by mass, even more preferably ≥1% by mass, and preferably ≤30% by mass, more preferably ≤15% by mass, and even more preferably ≤5% by mass.

[0013] From the viewpoint of exhibiting asphalt performance, 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; and from the viewpoint of storage stability, it is preferably ≤99.5% by mass, more preferably ≤99% by mass, still more preferably ≤98% by mass.

[0014] Polyester resin The asphalt composition of the present invention comprises a polyester resin. The polyester resin comprises a structural unit derived from an alcohol component and a structural unit derived from a carboxylic acid component, wherein the alcohol component comprises 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. Hereinafter, the alcohol component, the carboxylic acid component, physical properties of the polyester resin and the like will be described.

[0015] Alcohol component From the viewpoint of crack resistance, the alcohol component comprises an alkylene oxide adduct of bisphenol A in an amount of ≥30 mol%. The alkylene oxide adduct of bisphenol A is a diol compound obtained by adding one or more alkylene oxides to bisphenol A, and specific examples thereof include an alkylene oxide adduct of bisphenol A represented by the following formula (I).

[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 each represent the number of added moles of alkylene oxide, and are each independently a positive number of 0 or more.

[0018] In the alkylene oxide adduct of bisphenol A, the one or more added alkylene oxides include alkylene oxides having ≥1 and ≤4 carbon atoms, and are preferably ethylene oxide or propylene oxide. In other words, the alkylene oxide adduct of bisphenol A has one or more oxyalkylene groups having ≥1 and ≤4 carbon atoms, preferably an oxyethylene group or an oxypropylene group. In formula (I) above, the oxyalkylene group is OR 1 and R 1 O indicates this.

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

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

[0021] These alkylene oxide adducts of bisphenol A can be used individually or in combination of two or more. The content of the alkylene oxide adduct of bisphenol A in the alcohol component is ≥30 mol%, preferably ≥50 mol%, more preferably ≥70 mol%, even more preferably ≥80 mol%, even more preferably ≥90 mol%, and ≤100 mol%. In one preferred embodiment of the present invention, the alcohol component consists solely of an alkylene oxide adduct of bisphenol A.

[0022] The alcohol component may include 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, and polyhydric alcohols of trihydric or higher hydric value. These alcohol components can be used individually or in combination of two or more.

[0023] Preferably, the aliphatic diol is a linear or branched aliphatic diol with a main chain having ≥2 and ≤12 carbon atoms, and more preferably a linear or branched aliphatic diol with a main chain having ≥2 and ≤8 carbon atoms. Furthermore, the aliphatic diol is preferably a saturated aliphatic diol. Specific examples of aliphatic diols 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 alicyclic diols include hydrogenated bisphenol A (2,2-bis(4-hydroxycyclohexyl)propane), alkylene oxide adducts of hydrogenated bisphenol A, cyclohexanediol, and cyclohexanedimethanol.

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

[0026] The polyhydric alcohol with a valency of three or higher is preferably a trihydric alcohol. Examples of polyhydric alcohols with a valency of three or higher include glycerin, pentaerythritol, trimethylolpropane, and sorbitol.

[0027] The alcohol component may further contain monohydric aliphatic alcohols from the viewpoint of adjusting physical properties. Examples of monohydric aliphatic alcohols include lauryl alcohol, myristyl alcohol, palmityl alcohol, and stearyl alcohol. These monohydric aliphatic alcohols can be used individually or in combination of two or more.

[0028] Carboxylic acid components Examples of carboxylic acid components include aliphatic dicarboxylic acids, aromatic dicarboxylic acids, and polycarboxylic acids with a valency of 3 to 6. These carboxylic acid components can be used individually or in combination of two or more.

[0029] Examples of aliphatic dicarboxylic acids include those having a main chain with a carbon number of preferably ≥4, 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, dodecanediic acid, succinic acid substituted with an alkyl group having ≥1 and ≤20 carbon atoms or an alkenyl group having ≥2 and ≤20 carbon atoms, or their anhydrides, or their alkyl esters (for example, alkyl groups having ≥1 and 3 carbon atoms). Examples of substituted succinic acids include dodecyl succinic acid, dodecenyl succinic acid, and octenyl succinic acid. From the viewpoint of crack resistance, the aliphatic dicarboxylic acid is preferably the aforementioned alkenyl succinic acid, sebaciac acid, adipic acid, or their anhydrides, more preferably the aforementioned alkenyl succinic acid or sebaciac acid, or their anhydrides, and even more preferably the aforementioned alkenyl succinic acid or its anhydride.

[0030] Examples of aromatic dicarboxylic acids include phthalic acid, terephthalic acid, isophthalic acid, naphthalenedicarboxylic acid, or their anhydrides, or their alkyl esters (e.g., alkyl groups with ≥1 and ≥3 carbon atoms). Among the above aromatic dicarboxylic acids, isophthalic acid and terephthalic acid are preferred from the viewpoint of durability of asphalt pavement, and terephthalic acid is more preferred.

[0031] The polycarboxylic acid with a valency of 3 to 6 is preferably a tricarboxylic acid. Examples of polycarboxylic acids with a valency of 3 to 6 include trimellitic acid, 2,5,7-naphthalentricarboxylic acid, pyromellitic acid, or their acid anhydrides.

[0032] From the viewpoint of adjusting physical properties, the carboxylic acid component may further contain monovalent aliphatic carboxylic acids. Examples of monovalent aliphatic carboxylic acids include lauric acid, myristic acid, palmitic acid, stearic acid, and monovalent aliphatic carboxylic acids with ≥12 and ≤20 carbon atoms, such as alkyl (≥1 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 preferred embodiment of the present invention, the carboxylic acid component includes succinic acid (alkenyl succinic acid) substituted with an alkenyl group having ≥2 and ≤20 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%, more preferably ≥70 mol%, even more preferably ≥80 mol%, even more preferably ≥90 mol%, and ≤100 mol% from the same viewpoint as above. In one preferred embodiment of the present invention, the carboxylic acid component consists solely of succinic acid substituted with an alkenyl group having ≥2 and ≤20 carbon atoms.

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

[0035] Ester group concentration of 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, even more preferably ≥1.1 mmol / g, and preferably ≤3.0 mmol / g, more preferably ≤2.8 mmol / g, and even more preferably ≤2.5 mmol / g. Specifically, it is believed that when the ester group concentration of the polyester resin is within the above range, the self-cohesive force of the polyester resin is reduced, resulting in improved efficiency of the asphalt binder in coating the aggregate and thus improved crack resistance. The ester group concentration of the polyester resin can be determined by the method described in the examples.

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

[0037] The parameters of the polyester resin, including the glass transition temperature, acid value, hydroxyl value, melt viscosity at 90°C, number average molecular weight, and weight average molecular weight, can be measured by the method described in the examples. Note that the glass transition temperature, 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 modified polyester resin to the extent that its properties are not substantially impaired. Specifically, modified polyester resins include polyester resins that have been grafted or blocked with phenol, urethane, epoxy, etc., by methods described in Japanese Patent Publication No. 11-133668, Japanese Patent Publication No. 10-239903, Japanese Patent Publication No. 8-20636, etc. A preferred modified polyester resin is a urethane-modified polyester resin obtained by urethane elongation of a polyester resin with a polyisocyanate compound.

[0039] Polyester resin manufacturing method The method for producing the polyester resin constituting the asphalt modifier of the present invention is not particularly limited, but for example, it can be produced by polycondensation of the alcohol component and carboxylic acid component described above. The respective amounts of alcohol and carboxylic acid are such that the molar ratio of constituent units derived from the carboxylic acid component to those derived from the alcohol component (carboxylic acid component / alcohol component) falls within the numerical range mentioned above. From the viewpoint of reactivity, the temperature of the polycondensation reaction is preferably ≥160°C, more preferably ≥180°C, even more preferably ≥190°C, and preferably ≤260°C, more preferably ≤250°C, and even more preferably ≤240°C.

[0040] From the viewpoint of 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 di(2-ethylhexanoic acid)tin(II). From the viewpoint of reaction rate, the amount of esterification catalyst used is preferably ≥0.01 parts by mass, more preferably ≥0.1 parts by mass, even more preferably ≥0.2 parts by mass, and preferably ≤1.5 parts by mass, more preferably ≤1.0 parts by mass, and even more preferably ≤0.6 parts by mass, per 100 parts by mass of the total amount of alcohol and carboxylic acid components. In addition to the esterification catalyst, a co-catalyst can be used in the polycondensation reaction. Examples of co-catalysts include pyrogallol compounds such as gallic acid. The amount of co-catalyst used is preferably ≥0.001 parts by mass, more preferably ≥0.005 parts by mass, even more preferably ≥0.01 parts by mass, and preferably ≤0.15 parts by mass, more preferably ≤0.10 parts by mass, and even more preferably ≤0.05 parts by mass, based on 100 parts by mass of the total amount of the alcohol component and the carboxylic acid component.

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

[0042] Method for manufacturing asphalt composition The asphalt composition of the present invention can be produced by mixing asphalt with the polyester resin described above. Specifically, the asphalt composition is obtained by heating and melting asphalt, adding polyester resin, and stirring and mixing in a standard mixer until the polyester resin is uniformly dispersed in the asphalt. Standard mixers include homomixers, dissolvers, paddle mixers, ribbon mixers, screw mixers, planetary mixers, vacuum backflow mixers, roll mills, and twin-screw extruders.

[0043] The mixing temperature of the asphalt and the composite resin is preferably ≥140°C, more preferably ≥150°C, and more preferably ≤190°C, more preferably ≤180°C, and even more preferably ≤170°C, from the viewpoint of uniformly dispersing the polyester resin in the asphalt. Furthermore, the mixing time between the asphalt and the polyester resin is preferably ≥1 minute, more preferably ≥10 minutes, and even more preferably ≥30 minutes, from the viewpoint of uniformly dispersing the polyester resin in the asphalt, and preferably ≤48 hours, more preferably ≤30 hours, and even more preferably ≤24 hours, from the viewpoint of preventing thermal degradation of the asphalt composition. The asphalt composition of the present invention contains a binder that, when mixed with aggregate, forms a hot-mix asphalt composition. That is, the asphalt composition of the present invention is suitable for surface paving, and is particularly suitable for road paving.

[0044] Asphalt mixture This section describes asphalt mixtures, which are a suitable example of the use of asphalt compositions. The asphalt mixture comprises at least aggregate, asphalt binder, and polyester resin.

[0045] aggregate As aggregate, crushed stone, pebbles, gravel, sand, recycled aggregate, ceramics, etc., can be arbitrarily selected and used. In addition, either coarse aggregate with a particle size of ≥2.36 mm or fine aggregate with a particle size of ≤2.36 mm can be used. A combination of coarse and fine aggregate is preferred. From the viewpoint of durability of asphalt pavement, the aggregate content in the asphalt mixture is preferably ≥85% by mass, more preferably ≥90% by mass, more preferably ≥92% by mass, and more preferably ≤98% by mass, more preferably ≤97% by mass, and even more preferably ≤96% by mass, based on 100% by mass of the asphalt mixture.

[0046] additives In addition to the aggregate, asphalt, and polyester resin mentioned above, the asphalt mixture may also contain, if necessary, various additives conventionally used in asphalt mixtures, such as film-forming agents, thickening and stabilizing agents, and emulsifiers. The total content of these additives is preferably ≤50% by mass, more preferably ≤25% by mass, and even more preferably ≤5% by mass, of 100% by mass of the asphalt mixture.

[0047] Method for manufacturing asphalt mixtures There are no particular restrictions on the method for producing the asphalt mixture, and it may be produced by any method. Generally, it can be produced in accordance with the method for producing an asphalt mixture containing aggregate and asphalt. Specifically, one method involves adding and mixing the above-mentioned asphalt composition with heated aggregate.

[0048] From the viewpoint of uniformly mixing the materials, the temperature of the heated aggregate is preferably ≥130°C, more preferably ≥150°C, and even more preferably ≥160°C. From the viewpoint of preventing thermal degradation of the asphalt, it is preferably ≤230°C, more preferably ≤200°C, and even more preferably ≤170°C.

[0049] The mixing temperature of the aggregate and the asphalt composition is preferably ≥130°C, more preferably 150°C, and even more preferably ≥160°C, from the viewpoint of uniformly mixing the materials, and preferably ≤230°C, more preferably ≤200°C, and even more preferably ≤170°C, from the viewpoint of preventing thermal degradation of the asphalt. The mixing time between the aggregate and the asphalt composition is not particularly limited, but is preferably ≥30 seconds, more preferably ≥1 minute, even more preferably ≥2 minutes, and preferably ≤2 hours, more preferably ≤1 hour, and even more preferably ≤30 minutes.

[0050] From the viewpoint of durability of asphalt pavement, the method for producing the asphalt mixture preferably includes a curing step, which involves mixing aggregate and asphalt composition, and then holding the resulting asphalt mixture at the mixing temperature or a temperature higher than the mixing temperature. In the curing process of the asphalt mixture, the mixture may be further mixed. The holding time is preferably ≥0.5 hours, more preferably ≥1 hour, and even 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 methods Asphalt mixtures are suitable for road paving, and as described above, asphalt mixtures obtained by adding aggregate to an asphalt composition are used for road paving. The road paving method includes the step of applying the aforementioned asphalt mixture to the road to form an asphalt pavement layer. Specifically, the road paving method includes the step of mixing the aforementioned asphalt composition with heated aggregate to obtain an asphalt mixture (step 1), and the step of applying the asphalt mixture obtained in step 1 to the road to form an asphalt pavement layer (step 2). The asphalt pavement layer is preferably a base layer or a surface layer.

[0052] With regard to the embodiments described above, the present invention further discloses the following asphalt compositions.

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

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

[0055] <3> An asphalt composition comprising asphalt and polyester resin, An asphalt composition wherein the polyester resin comprises structural units derived from an alcohol component and structural units derived from a carboxylic acid component, and the alcohol component comprises an alkylene oxide adduct of bisphenol A in an amount of ≥70 mol%.

[0056] <4> The above conditions apply, where the average number of added moles of alkylene oxide in the alkylene oxide adduct of bisphenol A is ≥ 5 and ≤ 20. <1> ~ <3> An asphalt composition as described in any of the following.

[0057] <5> The alkylene oxide in the alkylene oxide adduct of bisphenol A is propylene oxide, as described above. <1> ~ <4> An asphalt composition as described in any of the following.

[0058] <6> The glass transition temperature of the polyester resin is ≥-70°C and ≤10°C. <1> ~ <5> An asphalt composition as described in any of the following.

[0059] <7> The glass transition temperature of the polyester resin is ≥-70°C and ≤3°C. <1> ~ <5> An asphalt composition as described in any of the following.

[0060] <8> The glass transition temperature of the polyester resin is ≥-70°C and ≤0°C, as described above. <1> ~ <5> An asphalt composition as described in any of the following.

[0061] <8> The glass transition temperature of the polyester resin is ≥-70°C and ≤-5°C. <1> ~ <5> An asphalt composition as described in any of the following.

[0062] <9> The melt viscosity of the polyester resin at 90°C is ≥300 mPa·s and ≤30,000 mPa·s. <1> ~ <8> An asphalt composition as described in any of the following.

[0063] <10> The ester group concentration of the polyester resin is ≥1.0 mmol / g and ≤3.0 mmol / g. <1> ~ <9> An asphalt composition as described in any of the following.

[0064] <11> The carboxylic acid component includes succinic acid substituted with an alkenyl group having ≥2 and ≤20 carbon atoms. <1> ~ <10> An asphalt composition as described in any of the following.

[0065] <12> The carboxylic acid component comprises ≥50 mol% and ≤100 mol% succinic acid substituted with an alkenyl group having ≥2 and ≤20 carbon atoms. <1> ~ <10> An asphalt composition as described in any of the following.

[0066] <13> The polyester resin content is ≥2 parts by mass and ≤5 parts by mass per 100 parts by mass of asphalt. <1> ~ <12> An asphalt composition as described in any of the following. [Examples]

[0067] Measurement method (1) Method for measuring the ester group concentration of polyester resin The ester group concentration of the polyester resin was calculated using the following formula. Ester group concentration (mmol / g) = A / B In the formula, A is the number of moles (mmol) of ester groups in the polyester resin, and B is the mass (g) of the resin, both of which were calculated using the following formulas. A(mmol) = 2 × (the smaller number of moles of the monomer component (alcohol component or carboxylic acid component) used in the charge (mmol)) × reaction rate B(g) = Total mass of alcohol component (g) - Mass of water produced during resin synthesis (g)

[0068] The reaction rate and the mass of water produced during polyester resin synthesis were calculated using the following formula. (i) Reaction rate when the alcohol component is in excess of the carboxylic acid component Reaction rate = 1 - (Acid value of polyester resin (mgKOH / g) / Acid value of monomer component at the time of charging (mgKOH / g)) Here, the acid value at the time of charging the monomer component was calculated as 2 × total number of moles of carboxylic acid component charged (mmol) × 56.1 / (total mass of alcohol component and carboxylic acid component charged (g)). (ii) Reaction rate when the carboxylic acid component is in excess of the alcohol component Reaction rate = Hydroxyl value of polyester resin (mgKOH / g) / Hydroxyl value of monomer component at the time of charging (mgKOH / g) Here, the hydroxyl value at the time of monomer component charging was calculated as 2 × total number of moles of alcohol component charged (mmol) × 56.1 / total mass of alcohol component and carboxylic acid component charged (g). (iii) The mass of water produced during the synthesis of polyester resin The mass of water produced during polyester resin synthesis (g) = 2 × 18 (molecular weight of water) × A

[0069] (2) Method for measuring the 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)).

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

[0071] (4) Method for measuring the melt viscosity of polyester resin at 90°C The melt viscosity of the polyester resin at 90°C was measured as follows. 15g of heated polyester resin was injected into the sample tube attached to the measuring device shown below. The spindle and heating device shown below were attached to the measuring device. The heating device was set to 90°C and heated for 2 hours. After that, the viscosity of the polyester resin was measured. Measurement 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 revolutions / minute Temperature: 90℃

[0072] (5) Method for measuring the number-average molecular weight and weight-average molecular weight of polyester resins The molecular weight distribution was measured by gel permeation chromatography (GPC) using the following method, and the number-average molecular weight (Mn) and weight-average molecular weight (Mw) were determined. (i) Preparation of sample solution The sample was dissolved in tetrahydrofuran at 60°C to a concentration of 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 Co., Ltd.) to remove insoluble components and obtain the sample solution. (ii) Measurement of molecular weight Using the measuring apparatus and analytical column described below, tetrahydrofuran was flowed as the eluent at a flow rate of 1 mL / min, and the column was stabilized in a constant temperature bath at 40°C. 100 μL of the sample solution obtained in (i) above was injected into the column, and the measurement was performed. The molecular weight of the sample was calculated based on a calibration curve prepared in advance. Measuring device: "HLC-8320GPC" (manufactured by Tosoh Corporation) Analysis columns: "GMHXL" + "G3000HXL" (manufactured by Tosoh Corporation) The calibration curve includes several types of monodisperse polystyrene "A-500" (5.0 x 10 2 ), "A-1000" (1.01 x 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 ) (all manufactured by Tosoh Corporation) were used in the form of a prepared calibration curve with the above as standard samples. Values in parentheses indicate 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 charged into a 10-liter four-necked flask equipped with a nitrogen inlet tube, a dehydration tube, a stirrer and a thermocouple. The mixture was held at 180°C for 1 hour under a nitrogen atmosphere, then heated at a rate of 10°C per hour and warmed 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, to obtain polyester resin E-1.

[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 Synthesis Example 1, except that the alcohol component and carboxylic acid component 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, dehydration tube, stirrer, and thermocouple. The mixture was maintained at 180°C for 1 hour under a nitrogen atmosphere, and then the temperature was increased by 10°C per hour for 3 hours until it reached 210°C. After reaching 210°C, the temperature and pressure were maintained at 8.0 kPa until the target acid value was achieved, yielding polyester resin E-4.

[0076] Synthesis Example 7 (Production of Polyester Resin C-2) The alcohol component, carboxylic acid component, esterification catalyst, and 2g 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, dehydration tube, stirrer, and thermocouple. The mixture was heated to 235°C under a nitrogen atmosphere and maintained at 235°C under atmospheric pressure for 5 hours, then maintained at 8.0kPa and 235°C for 1 hour. After that, 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, the mixture was maintained for 1 hour, and then the temperature and pressure were maintained at 16kPa and 210°C until the target acid value was reached, yielding polyester resin C-2.

[0077] [Table 1]

[0078] The ingredients and notes in the table are as follows: *1: Bisphenol A polyoxypropylene adduct, average number of moles added: 2.2 mol, molecular weight 350 *2: Polyoxypropylene adduct of bisphenol A, average number of moles added: 3.9 mol, molecular weight 417 *3: Bisphenol A polyoxypropylene adduct, average number of moles added: 5.8 mol, molecular weight 484 *4: Polyoxypropylene adduct of bisphenol A, average number of moles added: 16.3 mol, molecular weight 1027 *5: Polyoxyethylene adduct of bisphenol A, average number of moles added: 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: Measurement impossible because it far exceeds the measurement limit.

[0079] Example 1 600 g of straight asphalt (Associated Asphalt, performance grade (PG) 64-22) was heated to 165°C and weighed into a 500 mL paint can. 30 g of polyester resin E-1 obtained in Synthesis Example 1 (5 parts by mass per 100 parts by mass of asphalt) was added to this. After covering the container to prevent oxidation of the asphalt, the mixture was stirred at 165°C and a stirring speed of 200 rpm for 1 hour to prepare asphalt composition AS-1. Next, the obtained asphalt composition AS-1 was used based on AASHTO R30-02. The following aggregates and the asphalt composition were mixed at 165°C. Then, the mixture was kept warm at 160°C for 2 hours using a ventilated oven to prepare the asphalt mixture (hot-mixed asphalt). Specifically, using the following aggregate composition, asphalt composition AS-1 was blended with the hot-mixed asphalt with a target asphalt (straight asphalt) content of 5.9%, to obtain asphalt mixture M-1.

[0080] aggregate Aggregates manufactured by Blythe Construction were used as the aggregate. 2600g of aggregate contained 650g of gravel (coarse aggregate), 1690g of screenings (fine aggregate), and 260g of mountain sand (fine aggregate). The percentage of each component passing through is as follows: Passed mass%: gravel Sieve mesh size 9.50 mm: 90.4% by mass Sieve mesh size 8.00 mm: 73.3% by mass Sieve mesh size 4.75 mm: 24.8% by mass Sieve mesh size 2.80 mm: 3.9% by mass Sieve mesh size 1.00 mm: 1.2% by mass Sieve mesh size 0.50 mm: 0.8% by mass Screenings Sieve mesh size 9.50 mm: 100.0% mass Sieve mesh size 8.00 mm: 99.9% by mass Sieve mesh size 4.75 mm: 98.2% by mass Sieve mesh size 2.80 mm: 77.4% by mass Sieve mesh size 1.00 mm: 36.8% by mass Sieve mesh size 0.50 mm: 22.1% by mass Mountain sand Sieve mesh size 9.50 mm: 100.0% mass Sieve mesh size 8.00mm: 100.0% mass Sieve mesh size 4.75 mm: 98.0% by mass Sieve mesh size 2.80 mm: 94.2% by mass Sieve mesh size 1.00 mm: 70.6% by mass Sieve mesh size 0.50 mm: 33.6% by mass

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

[0082] Crack resistance evaluation: IDEAL-CT The crack resistance of asphalt mixtures was evaluated by measuring IDEAL-CT (CT-INDEX) using the following measuring device based on ASTM D8225-19. The results are shown in Table 2. A higher IDEAL-CT value indicates superior crack resistance of the pavement. Measurement device: 850 Digital Test Press (manufactured by Pine Instrument Co.) Additional device (attachment): Smart-Jig-Digital Data Collection (manufactured by InstroTek, Inc.)

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

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

[0085] Example 8 An asphalt mixture was obtained in the same manner as 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 of each per 100 parts by mass of asphalt). The Marshall stability and IDEAL-CT (CT-INDEX) were then measured in the same manner as in Example 1. The results are shown in Table 2.

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

[0087] [Table 2]

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

[0089] The data in Table 2 shows that the presence of polyester resin in the asphalt compositions of Examples 1 to 8 results in improved crack resistance while maintaining good Marshall stability, compared to the comparative asphalt composition. The Marshall stability and crack resistance (IDEAL-CT value) of asphalt pavement typically vary depending on the asphalt content. When polymer compounds are used as asphalt modifiers, the optimal 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 all examples.

Claims

1. An asphalt composition comprising asphalt and polyester resin, The polyester resin comprises structural units derived from an alcohol component and structural units derived from a carboxylic acid component, and the alcohol component comprises 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 ≤ 2.1°C. An asphalt composition in which the polyester resin content is ≥ 0.5 parts by mass and ≤ 15 parts by mass per 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 added moles of alkylene oxide in the alkylene oxide adduct of bisphenol A is ≥ 5 and ≤ 20.

5. The asphalt composition according to claim 1, wherein the carboxylic acid component comprises succinic acid substituted with an alkenyl group having ≥ 2 and ≤ 20 carbon atoms.

6. The asphalt composition according to claim 1, wherein the alkylene oxide adduct of bisphenol A is a propylene oxide adduct of bisphenol A.

7. The asphalt composition according to claim 1, wherein the carboxylic acid component is at least one selected from the group consisting of aliphatic dicarboxylic acids, aromatic dicarboxylic acids, and polycarboxylic acids with a valency of 3 to 6.

8. The asphalt composition according to claim 1, wherein the carboxylic acid component comprises an aliphatic dicarboxylic acid, and the number of carbon atoms in the main chain of the aliphatic dicarboxylic acid is ≥ 4 and ≤ 10.

9. The asphalt composition according to claim 1, wherein the acid value of the polyester resin is ≥ 2 mg KOH / g and ≤ 20 mg KOH / g.

10. The asphalt composition according to claim 1, wherein the number average molecular weight of the polyester resin is ≥ 2,500 and ≤ 10,000.

11. A method for producing an asphalt composition according to claim 1, A method for producing an asphalt composition, comprising the step of mixing the asphalt and the polyester resin at a mixing temperature of ≥140°C and ≤190°C.

12. An asphalt mixture comprising aggregate and the asphalt composition described in claim 1.

13. The asphalt mixture according to claim 12, wherein the aggregate content in the asphalt mixture is ≥85% by mass and ≤98% by mass of 100% by mass of the asphalt mixture.

14. A method for producing an asphalt mixture according to claim 12, A method for producing an asphalt mixture, comprising the step of mixing the aggregate and the asphalt composition at a mixing temperature of ≥130°C and ≤230°C.

15. A road paving method comprising: step 1 of mixing the asphalt composition described in claim 1 with heated aggregate to obtain an asphalt mixture; and step 2 of applying the asphalt mixture obtained in step 1 to a road to form an asphalt pavement layer.

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