Asphalt composition

Abstract

The present invention relates to an asphalt composition comprising asphalt (A) and a composite resin (B), wherein the composite resin (B) is a composite resin in which a polyester resin (b1) unit and a vinyl polymer (b2) unit are bonded via a covalent bond, the polyester resin (b1) unit comprises a structural unit derived from an alcohol component and a structural unit derived from a carboxylic acid component, and the vinyl polymer unit comprises a structural unit derived from styrene.

Description

[Technical Field]

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

[0002] Asphalt pavement containing asphalt mixtures is relatively easy to lay for paving roads, parking lots, freight yards, sidewalks, etc., and the time from the start of paving work until traffic resumes is short. Asphalt pavement has a road surface formed from an asphalt mixture in which aggregate is bound with asphalt, the paved road has good hardness and durability.

[0003] U.S. Patent Application Publication No. 2019-0233647 (Patent Document 1) discloses an asphalt composition that provides pavement surfaces with excellent storage stability at high temperatures and excellent dry strength. The asphalt composition contains asphalt, a polyester resin, and a dispersant. US Pat. No. 10,392,509 (Patent Document 2) discloses a high-performance asphalt composition having a waterproof function. Summary of the Invention

[0004] The present invention relates to an asphalt composition comprising asphalt (A) and a composite resin (B), wherein the composite resin (B) polyester A composite resin in which a (b1) unit and a vinyl polymer (b2) unit are bonded via a covalent bond, polyester The asphalt composition includes a (b1) unit containing a structural unit derived from an alcohol component and a structural unit derived from a carboxylic acid component, and the vinyl polymer unit contains a structural unit derived from styrene. DETAILED DESCRIPTION OF THE INVENTION

[0005] In the asphalt composition described in Patent Document 1, the mixture of asphalt and polyester resin may have a small amount of polyester resin precipitate formed in the asphalt mixture due to the difference in their specific gravities. This precipitate may cause variations in the strength of the asphalt mixture (hot mix asphalt). Even with the asphalt composition described in Patent Document 2, variations in strength of the asphalt mixture (hot mix asphalt) sometimes occurred. At asphalt paving sites, asphalt compositions are stored in tanks at high temperatures for long periods of time. Asphalt mixtures are also sometimes stored in silos for long periods of time. Therefore, there is a demand for improving the storage stability of asphalt compositions. The asphalt mixtures of the present invention exhibit improved storage stability, maintaining a homogeneous state for extended periods of time. Furthermore, the asphalt compositions of the present invention provide improved resistance to deterioration of asphalt pavement caused by fuel oils / oils.

[0006] The present invention relates to the following [1] to

[14] . [1] An asphalt composition comprising asphalt (A) and a composite resin (B), The composite resin (B) polyester A composite resin in which a (b1) unit and a vinyl polymer (b2) unit are bonded via a covalent bond, polyester An asphalt composition, wherein the (b1) unit contains a structural unit derived from an alcohol component and a structural unit derived from a carboxylic acid component, and the vinyl polymer (b2) unit contains a structural unit derived from styrene. [2] The asphalt composition according to [1], wherein the alcohol component contains an alkylene oxide adduct of bisphenol A. [3] The asphalt composition according to [1] or [2], wherein the carboxylic acid component contains an aromatic dicarboxylic acid. [4] The asphalt composition according to any one of [1] to [3], wherein the carboxylic acid component contains succinic acid substituted with an alkenyl group having 2 to 20 carbon atoms. [5] The asphalt composition according to any one of [1] to [4], wherein the vinyl polymer (b2) further contains a structural unit derived from a (meth)acrylic acid alkyl ester in which the alkyl group has 4 to 22 carbon atoms. [6] polyester The asphalt composition according to any one of [1] to [5], wherein the molar ratio of vinyl polymer (b2) units to (b1) units [(b2) / (b1)] is 10 / 90 to 45 / 55. [7] The asphalt composition according to any one of [1] to [6], wherein the SP value of the vinyl polymer (b2) is 9.5 to 10.5. [8] The asphalt composition according to any one of [1] to [3], wherein the glass transition temperature of the composite resin (B) is 40 to 100°C. [9] The asphalt composition according to any one of [1] to [8], wherein the polydispersity [Mw / Mn] of the composite resin (B) is 4 to 25.

[10] The asphalt composition according to any one of [1] to [9], wherein the composite resin (B) has a hydroxyl value of 10 to 35 mgKOH / g.

[11] The asphalt composition according to any one of [1] to

[10] , wherein the softening point of the composite resin (B) is 95 to 130°C.

[12] The asphalt composition according to any one of [1] to

[11] , wherein the content of the asphalt (A) is 85 to 99.5 wt.%.

[13] The asphalt composition according to any one of [1] to

[12] , wherein the content of the composite resin (B) is 0.5 to 15 wt. %.

[14] The asphalt composition according to any one of [1] to

[13] , wherein the content of the thermoplastic elastomer is ≦1 wt.%.

[0007] [Asphalt composition] The asphalt composition of the present invention comprises asphalt (A) and a composite resin (B), and the composite resin (B) polyester A composite resin in which a (b1) unit and a vinyl polymer (b2) unit are bonded via a covalent bond, polyesterThe (b1) unit contains a structural unit derived from an alcohol component and a structural unit derived from a carboxylic acid component, and the vinyl polymer unit contains a structural unit derived from styrene.

[0008] The present inventors have discovered that the above problems can be solved by making the asphalt composition contain asphalt and a specific composite resin. The reason why the effects of the present invention are obtained is not clear, but polyester The composite resin in which the vinyl polymer unit and the specific vinyl polymer unit are bonded via a covalent bond is polyester It has affinity with both asphalt and units. polyester It is believed that by improving the stability of the interface between the units, excellent storage stability can be achieved.

[0009] The definitions of various terms used in this specification are shown below. In the statement, polyester The carboxylic acid component includes not only the compound but also anhydrides that decompose during the reaction to produce an acid, and alkyl esters of each carboxylic acid (alkyl group having 1 to 3 carbon atoms). "Bisphenol A" is "2,2-bis(4-hydroxyphenyl)propane." "(Meth)acrylic acid" means at least one selected from methacrylic acid and acrylic acid, and the same applies to (meth)acrylate and (meth)acryloyl groups. The "solubility parameter value" and "SP value" in this specification are calculated by the method proposed by Fedors et al. [POLYMER ENGINEERING AND SCIENCE, FEBRUARY, 1974, Vol. 14, No. 2, ROBERT F. FEDORS. (pp. 147-154)].

[0010] <Asphalt> The asphalt composition of the present invention comprises asphalt. As the asphalt, various types of asphalt can be used, including, for example, straight asphalt, which is petroleum asphalt for paving, and modified asphalt. Straight asphalt is the residual bitumen material obtained by subjecting crude oil to atmospheric distillation or vacuum distillation. Modified asphalts include blown asphalt, polymer-modified asphalt modified with polymeric materials such as thermoplastic elastomers and thermoplastic resins (hereinafter also referred to as "polymer-modified asphalt"). Blown asphalt refers to asphalt obtained by heating a mixture of straight asphalt and heavy oil and then blowing air into it to oxidize it. The asphalt is preferably selected from straight asphalt and polymer-modified asphalt, with polymer-modified asphalt being more preferred from the viewpoint of durability of the asphalt pavement, and straight asphalt being more preferred from the viewpoint of versatility.

[0011] (thermoplastic elastomer) Examples of thermoplastic elastomers in polymer-modified asphalt include styrene / butadiene block copolymers (hereinafter also referred to as "SB"), styrene / butadiene / styrene block copolymers (hereinafter also referred to as "SBS"), styrene / butadiene random copolymers (hereinafter also referred to as "SBR"), styrene / isoprene block copolymers (hereinafter also referred to as "SI"), styrene / isoprene / styrene block copolymers (hereinafter also referred to as "SIS"), styrene / isoprene random copolymers (hereinafter also referred to as "SIR"), ethylene / vinyl acetate copolymers, ethylene / acrylic acid 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 those mentioned above, and at least one polymer selected from natural rubber.

[0012] Among these, from the viewpoint of durability of asphalt pavement, preferred thermoplastic elastomers are SB, SBS, SBR, SI, SIS, SIR, and ethylene / acrylic acid ester copolymers, more preferred are SB, SBS, SBR, SI, SIS, and SIR, and even more preferred are SBR and SBS. From the viewpoint of durability of the asphalt pavement, the content of the thermoplastic elastomer in the polymer modified asphalt is preferably ≦3 wt.% (mass %), more preferably ≦1.5 wt.%, and even more preferably ≦1 wt.%.

[0013] The total content of asphalt in the asphalt composition is preferably ≧85 wt.%, more preferably ≧90 wt.%, and even more preferably ≧95 wt.%, from the viewpoint of exhibiting asphalt performance, and is preferably ≦99.5 wt.%, more preferably ≦99 wt.%, and even more preferably ≦98 wt.%, from the viewpoint of storage stability.

[0014] <Composite resin (B)> The asphalt composition of the present invention further contains a composite resin (B), which is polyester A composite resin in which a (b1) unit and a vinyl polymer (b2) unit are bonded via a covalent bond, polyester The (b1) unit contains a structural unit derived from an alcohol component and a structural unit derived from a carboxylic acid component, and the vinyl polymer unit contains a structural unit derived from styrene. The composite resin (B) can be used alone or in combination of two or more types.

[0015] [ polyester (b1) polyester (b1) contains a structural unit derived from an alcohol component and a structural unit derived from a carboxylic acid component. polyester (b1) can be obtained by polycondensation of a carboxylic acid component and an alcohol component. The alcohol component and the carboxylic acid component will be described below. polyester (b1) can be used alone or in combination of two or more kinds.

[0016] (alcohol content) Examples of the alcohol component include aliphatic diols, aromatic diols, trihydric or higher polyhydric alcohols, etc. These alcohol components can be used alone or in combination of two or more. The alcohol component preferably contains a dihydric alcohol such as an aliphatic diol or an aromatic diol. From the viewpoint of the dry strength of the asphalt pavement, the alcohol component preferably contains an alkylene oxide adduct of bisphenol A (2,2-bis(4-hydroxyphenyl)propane), and more preferably contains an alkylene oxide adduct of bisphenol A represented by the following formula (I):

[0017] [ka]

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

[0019] 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 these, the propylene oxide adduct of bisphenol A alone, and a combination of the propylene oxide adduct of bisphenol A and the ethylene oxide adduct of bisphenol A are preferred.

[0020] In terms of obtaining excellent dry strength, the content of the alkylene oxide adduct of bisphenol A in 100 mol% of the alcohol component is preferably ≧65 mol%, more preferably ≧75 mol%, even more preferably ≧90 mol%, and even more preferably 100 mol%.

[0021] When the alcohol component contains a combination of a propylene oxide adduct of 2,2-bis(4-hydroxyphenyl)propane and an ethylene oxide adduct of 2,2-bis(4-hydroxyphenyl)propane, the molar ratio of the propylene oxide adduct of bisphenol A / the ethylene oxide adduct of bisphenol A is preferably ≧40 / 60, more preferably ≧50 / 50, and even more preferably ≧60 / 40, from the viewpoint of improving melt dispersibility in asphalt and obtaining dry strength, and is preferably ≦90 / 10, more preferably ≦80 / 20, and even more preferably ≦75 / 25, from the viewpoint of further improving melt dispersibility in asphalt. From the viewpoint of adjusting the physical properties, the alcohol component may contain a monohydric alcohol.

[0022] (carboxylic acid component) The carboxylic acid component preferably contains a dicarboxylic acid compound such as an aliphatic dicarboxylic acid or an aromatic dicarboxylic acid. Among these, from the viewpoint of the dry strength of the asphalt pavement, the carboxylic acid component preferably contains an aromatic dicarboxylic acid, more preferably one or more selected from terephthalic acid and isophthalic acid, and more preferably terephthalic acid. From the viewpoint of the dry strength of asphalt pavement made from the composite resin, the content of one or more selected from terephthalic acid and isophthalic acid in the carboxylic acid component is preferably ≧50 mol%, more preferably ≧60 mol%, even more preferably ≧80 mol%, and even more preferably 100 mol%, based on 100 mol% of the carboxylic acid component.

[0023] Examples of other carboxylic acid components include aromatic dicarboxylic acids other than terephthalic acid and isophthalic acid (hereinafter also referred to as "other aromatic dicarboxylic acids"), aliphatic dicarboxylic acids, trivalent or higher polycarboxylic acids, and their acid anhydrides and alkyl (C1 to C3) esters, etc. These carboxylic acid components can be used alone or in combination of two or more. The number of carbon atoms in the main chain of the aliphatic dicarboxylic acid is preferably within a range of 4 to 10, more preferably within a range of 4 to 8, and more preferably within a range of 4 to 6, from the viewpoint of improving dry strength. Specific examples include oxalic acid, malonic acid, maleic acid, fumaric acid, citraconic acid, itaconic acid, glutaconic acid, succinic acid, adipic acid, suberic acid, azelaic acid, sebacic acid, and dodecanedioic acid. Examples of aliphatic dicarboxylic acids also include succinic acids substituted with an alkyl group having 1 to 20 carbon atoms or an alkenyl group having 2 to 20 carbon atoms, such as dodecylsuccinic acid, dodecenylsuccinic acid, and octenylsuccinic acid, and preferably succinic acids substituted with an alkenyl group having 2 to 20 carbon atoms. The alkenyl group has 2 to 20 carbon atoms, and from the viewpoint of improving melt dispersibility in asphalt, it is preferably ≧9, more preferably ≧10, and preferably ≦18, more preferably ≦14. The alkenyl group may be either a straight chain or a branched chain, and is preferably a branched chain from the viewpoint of the dry strength of the asphalt pavement. Furthermore, from the viewpoint of melt dispersibility in asphalt and dry strength of asphalt pavement, the alkenyl succinic acid preferably consists of two or more types. Here, the "type" refers to the alkenyl group, and those with different chain lengths of the carbon number of the alkenyl group and structural isomers refer to different types of alkenyl succinic acid. Of these aliphatic dicarboxylic acids, from the viewpoint of further enhancing melt dispersibility in asphalt, preferred are fumaric acid and succinic acid substituted with an alkyl group having 1 to 20 carbon atoms or an alkenyl group having 2 to 20 carbon atoms, and more preferred is succinic acid substituted with an alkenyl group having 2 to 20 carbon atoms.

[0024] polyester When an aliphatic dicarboxylic acid is contained in the carboxylic acid component that is a raw material monomer, the content of the aliphatic dicarboxylic acid is, from the viewpoint of further improving dry strength, preferably ≧1 mol %, more preferably ≧5 mol %, even more preferably ≧10 mol %, and is preferably ≦40 mol %, more preferably ≦35 mol %, even more preferably ≦30 mol %, relative to 100 mol % of the carboxylic acid component.

[0025] Examples of trivalent or higher polyvalent carboxylic acids include trimellitic acid, 2,5,7-naphthalenetricarboxylic acid, pyromellitic acid, and acid anhydrides thereof. From the viewpoint of further improving dry strength, trimellitic acid or its acid anhydride is preferred. When the carboxylic acid component contains a trivalent or higher polycarboxylic acid, the content of the trivalent or higher polycarboxylic acid, relative to 100 mol% of the carboxylic acid component, is preferably ≧1 mol%, more preferably ≧3 mol%, even more preferably ≧5 mol%, and is preferably ≦30 mol%, more preferably ≦20 mol%, even more preferably ≦15 mol%, from the viewpoint of further improving dry strength. From the viewpoint of adjusting the physical properties, the carboxylic acid component may contain a monocarboxylic acid compound.

[0026] (molar ratio of structural units derived from carboxylic acid components to structural units derived from alcohol components) From the viewpoint of adjusting the hydroxyl value, the molar ratio of the structural units derived from the carboxylic acid component to the structural units derived from the alcohol component [carboxylic acid component / alcohol component] is preferably ≧0.7, more preferably ≧0.8, and is preferably ≦1.5, more preferably ≦1.3, even more preferably ≦1.1, and even more preferably ≦1.0.

[0027] [Vinyl polymer (b2)] The vinyl polymer (b2) contains a structural unit derived from styrene, that is, the vinyl polymer (b2) is an addition polymer of raw material monomers containing styrene.

[0028] The styrene content in the raw material monomers of the vinyl polymer (b2) is preferably ≧50 wt.%, more preferably ≧65 wt.%, even more preferably ≧70 wt.%, and is ≦100 wt.%, preferably ≦95 wt.%, more preferably ≦90 wt.%, even more preferably ≦85 wt.%. Examples of raw material monomers other than styrene include styrene-based compounds other than styrene, such as methylstyrene, α-methylstyrene, β-methylstyrene, tert-butylstyrene, chlorostyrene, chloromethylstyrene, methoxystyrene, and styrenesulfonic acid or a salt thereof; (meth)acrylic acid esters, such as alkyl (meth)acrylate, benzyl (meth)acrylate, and dimethylaminoethyl (meth)acrylate; olefins, such as ethylene, propylene, and butadiene; halovinyl compounds, such as vinyl chloride; vinyl esters, such as vinyl acetate and vinyl propionate; vinyl ethers, such as vinyl methyl ether; vinylidene halides, such as vinylidene chloride; and N-vinyl compounds, such as N-vinylpyrrolidone. Among these, (meth)acrylic acid esters are preferred, and (meth)acrylic acid alkyl esters are more preferred.

[0029] From the viewpoints of storage stability and oil resistance, the number of carbon atoms in the alkyl group in the alkyl (meth)acrylate is preferably ≧1, more preferably ≧4, even more preferably ≧10, still more preferably ≧14, and preferably ≦24, more preferably ≦22, even more preferably ≦20.

[0030] Examples of alkyl (meth)acrylates include methyl (meth)acrylate, ethyl (meth)acrylate, (iso)propyl (meth)acrylate, (iso- or tertiary)butyl (meth)acrylate, (iso)amyl (meth)acrylate, cyclohexyl (meth)acrylate, 2-ethylhexyl (meth)acrylate, (iso)octyl (meth)acrylate, (iso)decyl (meth)acrylate, (iso)dodecyl (meth)acrylate, (iso)palmityl (meth)acrylate, (iso)stearyl (meth)acrylate, and (iso)behenyl (meth)acrylate. Among these, preferred are butyl (meth)acrylate, 2-ethylhexyl (meth)acrylate, and stearyl (meth)acrylate, more preferred are 2-ethylhexyl (meth)acrylate, and even more preferred are 2-ethylhexyl acrylate. The raw material monomer other than styrene in the vinyl polymer (b2) is preferably an alkyl (meth)acrylate having ≧4 and ≦22 carbon atoms.

[0031] The content of (meth)acrylic acid ester in the raw material monomers of the vinyl polymer (b2) is preferably ≧5 wt.%, more preferably ≧10 wt.%, even more preferably ≧15 wt.%, and preferably ≦50 wt.%, more preferably ≦40 wt.%, even more preferably ≦30 wt.%.

[0032] The total content of styrene and (meth)acrylic acid ester in the raw material monomers of the vinyl polymer (b2) is preferably ≧80 wt.%, more preferably ≧90 wt.%, even more preferably ≧95 wt.%, and still more preferably 100 wt.%, based on 100 wt.% of the total amount of raw material monomers.

[0033] [Ambireactive Monomer] Composite resin (B) is polyester The vinyl polymer unit preferably has a structural unit derived from a bireactive monomer that is bonded to the vinyl polymer unit via a covalent bond. The "structural unit derived from a bireactive monomer" refers to a unit formed by reaction of the functional group and the unsaturated bond site of the bireactive monomer.

[0034] Examples of bireactive monomers include addition-polymerizable monomers having at least one functional group selected from a hydroxy group, a carboxy group, an epoxy group, a primary amino group, and a secondary amino group in the molecule. Among these, from the viewpoint of reactivity, addition-polymerizable monomers having at least one functional group selected from a hydroxy group and a carboxy group are preferred, and addition-polymerizable monomers having a carboxy group are more preferred. Examples of addition-polymerizable monomers having a carboxy group include acrylic acid, methacrylic acid, fumaric acid, and maleic acid. Examples of addition-polymerizable monomers having a hydroxy group include 2-hydroxyethyl methacrylate. Among these, from the viewpoint of reactivity in both polycondensation reactions and addition polymerization reactions, acrylic acid and methacrylic acid are preferred, and acrylic acid is more preferred.

[0035] The amount of the bireactive monomer-derived structural unit of the composite resin is polyester The amount is preferably ≧1 molar part, more preferably ≧5 molar parts, and even more preferably ≧8 molar parts, and is preferably ≦30 molar parts, more preferably ≦25 molar parts, and even more preferably ≦20 molar parts, relative to 100 molar parts of the alcohol component of the unit.

[0036] [Hydrocarbon wax] The composite resin may further contain a structural unit derived from a hydrocarbon wax having at least one of a carboxy group and a hydroxyl group.

[0037] The hydrocarbon wax-derived structural unit may be, for example, a hydroxyl group or a carboxyl group that has reacted, polyester The units are covalently bonded to a hydrocarbon wax. The hydrocarbon wax preferably has at least one of a carboxy group and a hydroxyl group. The hydrocarbon wax may have either a hydroxyl group or a carboxy group, or both, but preferably has a hydroxyl group and a carboxyl group. The hydrocarbon wax can be obtained, for example, by modifying an unmodified hydrocarbon wax by a known method. Examples of raw materials for the hydrocarbon wax include paraffin wax, Fischer-Tropsch wax, microcrystalline wax, polyethylene wax, and polypropylene wax. Among these, paraffin wax and Fischer-Tropsch wax are preferred.

[0038] Commercially available hydrocarbon waxes having hydroxyl groups include, for example, "Unilin 700," "Unilin 425," and "Unilin 550" (all manufactured by Baker Petrolite).

[0039] Examples of hydrocarbon waxes having a carboxy group include acid-modified hydrocarbon waxes. An example of a commercially available hydrocarbon wax having a carboxy group is maleic anhydride-modified ethylene-propylene copolymer "HIWAX 1105A" (manufactured by Mitsui Chemicals, Inc.).

[0040] Commercially available hydrocarbon waxes having a hydroxyl group and a carboxyl group include, for example, "Paracol 6420," "Paracol 6470," and "Paracol 6490" (all manufactured by Nippon Seiro Co., Ltd.).

[0041] The hydroxyl value of the hydrocarbon wax is preferably ≧35 mgKOH / g, more preferably ≧50 mgKOH / g, even more preferably ≧70 mgKOH / g, and preferably ≦180 mgKOH / g, more preferably ≦150 mgKOH / g, even more preferably ≦120 mgKOH / g.

[0042] The acid number of the hydrocarbon wax is preferably ≧1 mgKOH / g, more preferably ≧5 mgKOH / g, even more preferably ≧10 mgKOH / g, and preferably ≦30 mgKOH / g, more preferably ≦25 mgKOH / g, even more preferably ≦20 mgKOH / g.

[0043] The sum of the hydroxyl number and the acid number of the hydrocarbon wax is preferably ≧35 mgKOH / g, more preferably ≧40 mgKOH / g, even more preferably ≧60 mgKOH / g, and preferably ≦210 mgKOH / g, more preferably ≦175 mgKOH / g, even more preferably ≦140 mgKOH / g.

[0044] The number average molecular weight of the hydrocarbon wax is preferably ≧500, more preferably ≧600, even more preferably ≧700, and preferably ≦2,000, more preferably ≦1,700, even more preferably ≦1,500. The hydroxyl value and acid value of the hydrocarbon wax are measured by the methods described in the Examples. The number average molecular weight of the hydrocarbon wax is measured by gel permeation chromatography using chloroform as a solvent and polystyrene as a standard substance.

[0045] In composite resin polyester The unit content is polyester The content of the vinyl polymer unit is preferably ≧40 wt.%, more preferably ≧45 wt.%, even more preferably ≧55 wt.%, and is preferably ≦90 wt.%, more preferably ≦85 wt.%, even more preferably ≦75 wt.%, based on the total amount of the vinyl polymer unit, the vinyl polymer unit, and the bireactive monomer-derived structural units.

[0046] The content of vinyl polymer units in the composite resin is polyester It is preferably ≧10 wt.%, more preferably ≧15 wt.%, even more preferably ≧25 wt.%, and is preferably ≦60 wt.%, more preferably ≦55 wt.%, even more preferably ≦45 wt.%, based on the total amount of the units, vinyl polymer units, and structural units derived from bireactive monomers.

[0047] The content of the constitutional unit derived from the bireactive monomer in the composite resin is polyesterIt is preferably ≧0.1 wt.%, more preferably ≧0.5 wt.%, even more preferably ≧0.8 wt.%, and is preferably ≦10 wt.%, more preferably ≦5 wt.%, even more preferably ≦3 wt.%, based on the total amount of the units, vinyl polymer units, and structural units derived from bireactive monomers.

[0048] In composite resin polyester The mass ratio of the vinyl polymer (b2) unit to the (b1) unit [(b2) / (b1)] is preferably ≧10 / 90, more preferably ≧15 / 85, and also preferably ≦45 / 55, more preferably ≦40 / 60, and even more preferably ≦25 / 75.

[0049] The amount of hydrocarbon wax-derived constituent units in the composite resin is polyester The content of the vinyl polymer unit, vinyl polymer unit, and bireactive monomer-derived structural unit is preferably ≧0.1 parts by mass, more preferably ≧0.5 parts by mass, and even more preferably ≧1 part by mass, and is preferably ≦10 parts by mass, more preferably ≦8 parts by mass, and even more preferably ≦6 parts by mass, relative to 100 parts by mass in total of the vinyl polymer unit, vinyl polymer unit, and bireactive monomer-derived structural unit.

[0050] In the composite resin, polyester The total amount of the units, vinyl polymer units, structural units derived from bireactive monomers, and structural units derived from hydrocarbon waxes is preferably ≧80 wt.%, more preferably ≧90 wt.%, even more preferably ≧95 wt.%, and is ≦100 wt.%, preferably 100 wt.%.

[0051] The above amount is polyester The ratio of the amount of the unit, raw material monomer of the vinyl polymer unit, bireactive monomer, hydrocarbon wax-derived structural unit, and radical polymerization initiator is calculated as a standard. polyester It does not include the amount of water removed by polycondensation in the unit, etc. When a radical polymerization initiator is used, the mass of the radical polymerization initiator is calculated by including it in the vinyl polymer unit.

[0052] [Physical properties of composite resin] The softening point of the composite resin is preferably ≧95°C, more preferably ≧100°C, and preferably ≦130°C, more preferably ≦125°C, and even more preferably ≦120°C.

[0053] The glass transition temperature of the composite resin is preferably ≧40°C, more preferably ≧42°C, even more preferably ≧45°C, and preferably ≦100°C, more preferably ≦88°C, even more preferably ≦70°C.

[0054] The acid value of the composite resin is preferably ≧1 mgKOH / g, more preferably ≧3 mgKOH / g, even more preferably ≧5 mgKOH / g, and preferably ≦40 mgKOH / g, more preferably ≦30 mgKOH / g, even more preferably ≦25 mgKOH / g. The hydroxyl value of the composite resin is preferably ≧10 mgKOH / g, more preferably ≧11 mgKOH / g, even more preferably ≧15 mgKOH / g, and preferably ≦35 mgKOH / g, more preferably ≦33 mgKOH / g, even more preferably ≦30 mgKOH / g. The number average molecular weight (Mn) of the composite resin is preferably ≧1,800, more preferably ≧2,000, even more preferably ≧2,200, and preferably ≦5,000, more preferably ≦4,500, even more preferably ≦4,000. The weight average molecular weight (Mw) of the composite resin is preferably ≧15,000, more preferably ≧20,000, even more preferably ≧25,000, and preferably ≦100,000, more preferably ≦80,000, even more preferably ≦60,000. From the same viewpoint, the polydispersity (Mw / Mn) of the composite resin is preferably ≧4, more preferably ≧10, preferably ≧15, and preferably ≦25, more preferably ≦23, and even more preferably ≦20. The SP value of the composite resin is preferably ≥ 9.5 (cal / cm 3 ) 1 / 2 , more preferably ≧9.6 (cal / cm 3 ) 1 / 2 , and more preferably ≧9.7 (cal / cm3 ) 1 / 2 and preferably ≦10.5 (cal / cm 3 ) 1 / 2 , more preferably ≦10.3 (cal / cm 3 ) 1 / 2 , and more preferably ≦10.2 (cal / cm 3 ) 1 / 2 , more preferably ≦10.1 (cal / cm 3 ) 1 / 2 is. Composite resin polyester The SP value of the unit is preferably ≥ 10.5 (cal / cm 3 ) 1 / 2 , more preferably ≧10.6 (cal / cm 3 ) 1 / 2 , and more preferably ≧10.7 (cal / cm 3 ) 1 / 2 and preferably ≦12.0 (cal / cm 3 ) 1 / 2 , more preferably ≦11.5 (cal / cm 3 ) 1 / 2 , and more preferably ≦11.2 (cal / cm 3 ) 1 / 2 is. The SP value of the vinyl polymer unit of the composite resin is preferably ≥ 9.5 (cal / cm 3 ) 1 / 2 , more preferably ≧9.6 (cal / cm 3 ) 1 / 2 , and more preferably ≧9.7 (cal / cm 3 ) 1 / 2 and preferably ≦10.5 (cal / cm 3 ) 1 / 2 , more preferably ≦10.3 (cal / cm 3 ) 1 / 2 , and more preferably ≦10.2 (cal / cm 3 ) 1 / 2 , more preferably ≦10.1 (cal / cm 3 ) 1 / 2 is.

[0055] The softening point, glass transition temperature, and acid value of the composite resin can be appropriately adjusted by the type and amount of raw material monomers, as well as production conditions such as reaction temperature, reaction time, and cooling rate, and these values ​​can be determined by the method described in the Examples. When two or more composite resins are used in combination, it is preferable that the softening point, glass transition temperature, and acid value of the mixture thereof each fall within the above-mentioned ranges.

[0056] [Method for producing composite resin] The composite resin is, for example, polyester The vinyl polymer may be produced by a method including a step A of carrying out a polycondensation reaction between an alcohol component and a carboxylic acid component of the unit, and a step B of carrying out an addition polymerization reaction between a raw material monomer of the vinyl polymer unit and a bireactive monomer. When the composite resin has structural units derived from a hydrocarbon wax, in the above-mentioned step A, for example, a polycondensation reaction of an alcohol component and a carboxylic acid component is carried out in the presence of a hydrocarbon wax having at least one of a hydroxyl group and a carboxyl group. Step B may be carried out after step A, step B may be carried out after step A, or step A and step B may be carried out simultaneously.

[0057] (Process A) In step A, if necessary, polycondensation may be carried out using an esterification catalyst such as tin(II) di(2-ethylhexanoate), dibutyltin oxide, or titanium diisopropylate bistriethanolamine in an amount of 0.01 to 5 parts by mass per 100 parts by mass of the total amount of the alcohol component and the carboxylic acid component, and an esterification promoter such as gallic acid (same as 3,4,5-trihydroxybenzoic acid) in an amount of 0.001 to 0.5 parts by mass per 100 parts by mass of the total amount of the alcohol component and the carboxylic acid component. When a monomer having an unsaturated bond such as fumaric acid is used in the polycondensation reaction, a radical polymerization inhibitor may be used, if necessary, in an amount of preferably 0.001 to 0.5 parts by mass per 100 parts by mass of the total amount of the alcohol component and the carboxylic acid component. Examples of the radical polymerization inhibitor include 4-tert-butylcatechol.

[0058] The temperature of the polycondensation reaction is preferably ≧120° C., more preferably ≧160° C., even more preferably ≧180° C., and preferably ≦250° C., more preferably ≦245° C., even more preferably ≦240° C. The polycondensation may be carried out in an inert gas atmosphere.

[0059] (Process B) Examples of polymerization initiators for the addition polymerization reaction include peroxides such as di-tert-butyl peroxide, persulfates such as sodium persulfate, and azo compounds such as 2,2'-azobis(2,4-dimethylvaleronitrile). The amount of the radical polymerization initiator used is preferably ≧1 part by mass and ≦20 parts by mass relative to 100 parts by mass of the raw material monomers of the addition polymerization resin unit. The temperature of the addition polymerization reaction is preferably ≧110°C, more preferably ≧130°C, and preferably ≦220°C, more preferably ≦200°C, and even more preferably ≦180°C.

[0060] A preferred method is to subject a part of the carboxylic acid component to a polycondensation reaction in step A, then carry out step B, and then add the remainder of the carboxylic acid component to the polymerization system, thereby further promoting the polycondensation reaction of step A and, if necessary, the reaction with the bireactive monomer. polyester Of the carboxylic acid components that are raw materials for the units, it is preferable that trivalent or higher polycarboxylic acids (for example, trimellitic acid) are not added in the initial polycondensation reaction of step A, but are added after step B is carried out. When the reaction rate of the polycondensation reaction in the first step A reaches, for example, 90% or more, the pressure in the system is reduced and cooled, and then raw material monomers for the vinyl polymer unit and a bireactive monomer are added dropwise to the system to carry out the addition polymerization reaction in step B. The dropwise addition temperature of the raw material monomers for the vinyl polymer unit and the bireactive monomer in step B is preferably ≥ 155°C, more preferably ≥ 157°C, even more preferably ≥ 160°C, and preferably ≤ 190°C, more preferably ≤ 180°C, and even more preferably ≤ 170°C. The dropwise addition time of the raw material monomers for the vinyl polymer unit and the bireactive monomer in step B is preferably ≥ 0.5 hours, more preferably ≥ 1.5 hours, even more preferably ≥ 2.5 hours, and preferably ≤ 5 hours, more preferably ≤ 4 hours, and even more preferably ≤ 3.5 hours. After carrying out step B, polyester The remainder of the carboxylic acid component, which is the raw material for the unit, is added to the polymerization system, and the polycondensation reaction of step A and the reaction with the bireactive monomer, if necessary, are further promoted. The reaction time for the trivalent or higher polycarboxylic acid (e.g., trimellitic acid) is preferably ≧4 hours, more preferably ≧5 hours, even more preferably ≧6 hours, and preferably ≦8 hours, more preferably ≦7.5 hours, even more preferably ≦7 hours.

[0061] From the viewpoint of storage stability, the content of the composite resin in the asphalt composition is preferably ≧0.5 wt.%, more preferably ≧1 wt.%, and even more preferably ≧2 wt.%, and from the viewpoint of exhibiting asphalt performance, it is preferably ≦15 wt.%, more preferably ≦10 wt.%, and even more preferably ≦5 wt.%.

[0062] [Method for producing asphalt composition] The asphalt composition of the present invention can be produced by mixing asphalt with the composite resin. Specifically, the asphalt is heated and melted, the composite resin is added, and the mixture is stirred and mixed in a commonly used mixer until the composite resin is uniformly dispersed in the asphalt, thereby obtaining the asphalt composition. Commonly used mixers include a homomixer, a dissolver, a paddle mixer, a ribbon mixer, a screw mixer, a planetary mixer, a vacuum countercurrent mixer, a roll mill, and a twin-screw extruder.

[0063] From the viewpoint of uniformly dispersing the composite resin in the asphalt, the mixing temperature of the asphalt and the composite resin is preferably ≧140°C, more preferably ≧150°C, even more preferably ≧160°C, and preferably ≦230°C, more preferably ≦210°C, even more preferably ≦200°C. The mixing time between the asphalt and the composite resin is preferably ≧1 minute, more preferably ≧10 minutes, and even more preferably ≧30 minutes from the viewpoint of uniform dispersion of the composite resin in the asphalt, and is 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 is a binder composition, and can be used for paving after, for example, adding aggregate to the asphalt composition to form an asphalt mixture. In other words, the asphalt composition of the present invention is suitable for paving, and particularly suitable for road paving.

[0064] [Asphalt mixture] An asphalt mixture, which is a suitable example of the use of the asphalt composition, will now be described. The asphalt mixture contains aggregate and the asphalt composition. That is, the asphalt mixture contains at least aggregate, asphalt, and the composite resin.

[0065] <Aggregate> The aggregate can be selected from crushed stone, boulders, gravel, sand, recycled aggregate, ceramics, etc. In addition, the aggregate can be either coarse aggregate with a particle size of ≥ 2.36 mm or fine aggregate with a particle size ≤ 2.36 mm, with a combination of coarse and fine aggregate being preferred. From the viewpoint of the durability of the asphalt pavement, the aggregate content in the asphalt mixture is preferably ≧85 wt.%, more preferably ≧90 wt.%, more preferably ≧92 wt.%, and preferably ≦98 wt.%, more preferably ≦97 wt.%, and even more preferably ≦96 wt.%, out of 100 wt.% of the asphalt mixture.

[0066] <Additives> In addition to the aggregate, asphalt, and polyester described above, various additives conventionally used in asphalt mixtures, such as film-forming agents, thickening stabilizers, and emulsifiers, may be added to the asphalt mixture as necessary. The total content of these additives is preferably ≦50 wt.%, more preferably ≦25 wt.%, and even more preferably ≦5 wt.%, based on 100 wt.% of the asphalt mixture.

[0067] [Asphalt mixture manufacturing method] There are no particular limitations on the method for producing the asphalt mixture, and any method may be used. Generally, the method can be carried out in accordance with the method for producing an asphalt mixture containing aggregate and asphalt. Specifically, the asphalt composition described above can be added to heated aggregate and mixed.

[0068] The temperature of the heated aggregate is preferably ≧130°C, more preferably ≧150°C, and even more preferably ≧170°C from the viewpoint of uniformly mixing the materials, and is preferably ≦230°C, more preferably ≦210°C, and even more preferably ≦200°C from the viewpoint of preventing thermal degradation of the asphalt.

[0069] The mixing temperature for the aggregate and asphalt composition is preferably ≧130°C, more preferably ≧150°C, and even more preferably ≧170°C from the viewpoint of uniformly mixing the materials, and is preferably ≦230°C, more preferably ≦210°C, and even more preferably ≦200°C from the viewpoint of preventing thermal degradation of the asphalt. The mixing time of 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 is preferably ≦2 hours, more preferably ≦1 hour, even more preferably ≦30 minutes.

[0070] From the viewpoint of the durability of the asphalt pavement, the method for producing an asphalt mixture preferably includes a step of mixing aggregate and an asphalt composition and then holding the resulting asphalt mixture at the above-mentioned mixing temperature or at a temperature equal to or higher than the mixing temperature. In the step of holding the asphalt mixture, the mixture may be further mixed. The retention 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.

[0071] [Road paving method] The asphalt mixture is suitable for road paving, and as described above, an asphalt mixture obtained by adding aggregate to an asphalt composition is used for road paving. The road paving method includes the steps of applying the asphalt mixture to a road to form an asphalt pavement layer. Specifically, the road paving method includes the steps of mixing the asphalt composition with heated aggregate to obtain an asphalt mixture (Step 1), and applying the asphalt mixture obtained in Step 1 to a road to form an asphalt pavement layer (Step 2). The asphalt pavement layer is preferably a base layer or a surface layer.

[0072] The asphalt mixture may be compacted and applied using known equipment and methods. When used as a hot asphalt mixture, the compaction temperature is preferably ≥ 100°C, more preferably ≥ 120°C, even more preferably ≥ 130°C, and preferably ≤ 200°C, more preferably ≤ 180°C, from the viewpoint of adjusting the void ratio. The porosity of the resulting pavement can be, for example, preferably ≧3%, more preferably ≧4%, and preferably ≦8%, more preferably ≦7.5%.

[0073] In the following Preparation Examples, Production Examples, Examples and Comparative Examples, "parts" and "%" mean "parts by mass", "% by mass" or "wt. %" unless otherwise specified.

[0074] The physical properties of the resin were measured and evaluated by the following methods. (1) Method for measuring the softening point of resin Using a flow tester (Shimadzu Corporation, product name: CFT-500D), 1 g of sample was heated at a temperature increase rate of 6°C / min, while applying a load of 1.96 MPa with the plunger, and extruded from a nozzle 1 mm in diameter and 1 mm in length. The plunger depression distance of the flow tester was plotted against the temperature, and the temperature at which half of the sample flowed out was taken as the softening point.

[0075] (2) Method for measuring the glass transition temperature of composite resins Using a differential scanning calorimeter (TA Instruments Japan, product name: DSC Q20), 0.01-0.02 g of sample was weighed into an aluminum pan and heated to 200°C and then cooled to 0°C at a rate of 10°C / min. The sample was then heated at a rate of 10°C / min, and the endothermic peak was measured. The glass transition temperature (Tg) was determined as the temperature at the intersection of the extension of the baseline below the highest endothermic peak temperature and the tangent line representing the maximum slope from the rising part of the peak to the peak apex.

[0076] (3) Method for measuring the acid value of composite resin Measurements were performed according to the neutralization titration method described in JIS K0070:1992, except that the measurement solvent was changed from a mixed solvent of ethanol and ether to a mixed solvent of acetone and toluene (acetone:toluene = 1:1 (volume ratio)).

[0077] (4) Measurement method for hydroxyl value of composite resin The measurement was carried out according to the neutralization titration method described in JIS K0070:1992, except that the measurement solvent was changed from a mixed solvent of ethanol and ether to tetrahydrofuran.

[0078] (5) Methods for measuring number-average molecular weight, weight-average molecular weight, and polydispersity of resin The molecular weight distribution was measured by gel permeation chromatography (GPC) using the following method to determine the number average molecular weight (Mn), weight average molecular weight (Mw), peak top molecular weight (Mp) and polydispersity (Mw / Mn). (5-1) Preparation of sample solution The sample was dissolved in tetrahydrofuran at 60° C. to a concentration of 0.5 g / 100 mL. Next, at room temperature, this solution was filtered using a PTFE-type membrane filter with a pore size of 0.2 μm (manufactured by Toyo Roshi Kaisha, Ltd., trade name: DISMIC-25JP) to remove insoluble components, thereby obtaining a sample solution. (5-2) Molecular weight measurement The following measurement equipment and analytical column were used, and tetrahydrofuran was used as the eluent at a flow rate of 1 mL / min. The column was stabilized in a thermostatic bath at 40°C. 100 μL of the sample solution obtained in (5-1) 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" (Tosoh Corporation) Analytical column: "GMHXL" + "G3000HXL" (manufactured by Tosoh Corporation) The calibration curve is based on several types of monodisperse polystyrene "A-500" (5.0 × 10 2 ), "A-1000" (1.01 x 10 3 ), "A-2500" (2.63 x 10 3 ), "A-5000" (5.97 x 10 3 ), "F-1" (1.02 x 10 3 ), "F-2" (1.81 x 10 4 ), "F-4" (3.97 x 10 4 ), "F-10" (9.64 x 10 4 ), "F-20" (1.90 x 10 5 ), "F-40" (4.27 x 10 5 ), "F-80" (7.06 x 10 5 ), "F-128" (1.09 x 10 6 ) (all manufactured by Tosoh Corporation) were used as standard samples. The numbers in parentheses indicate molecular weights.

[0079] (6) polyester Calculation method for SP value of unit, vinyl polymer unit and entire composite resin polyester The solubility parameters (SP values) of the unit, the vinyl polymer unit and the entire composite resin were calculated using the method of Fedors et al. [Polym. Eng. Sci., 14(2)147(1974)].

[0080] (7) Method for measuring the glass transition temperature of vinyl polymer units During the composite resin production process, unreacted monomers from the vinyl polymer unit were removed at 8.3 kPa, and then a 10 g sample was taken. To remove unreacted alcohol and carboxylic acid monomers, the mixture was mixed with 50 g of ethanol, and the insoluble matter was collected by vacuum filtration. The insoluble matter was dried under reduced pressure at room temperature for at least one day, and the glass transition temperature of the vinyl polymer unit was measured according to the "Glass transition temperature of composite resin" method described above.

[0081] Production Example 1 (Production of Composite Resin A-1) The alcohol and carboxylic acid components shown in Table 1 were placed in a 10-liter four-neck flask equipped with a nitrogen inlet tube, dehydration tube, stirrer, and thermocouple, and heated to 160°C to dissolve. The bireactive monomer, polymerization initiator, and vinyl polymer raw material monomers shown in Table 1 were added dropwise over 1 hour using a dropping funnel while maintaining the temperature in the bath at 160±3°C. Stirring was then continued for 1 hour while maintaining the temperature in the bath at 160±3°C to polymerize the vinyl polymer raw material monomers and acrylic acid. The mixture was then stirred at 8.3 kPa for 1 hour to remove unreacted vinyl polymer raw material monomers. The esterification catalyst and esterification cocatalyst were then added, heated to 235°C, and reacted for 8 hours at atmospheric pressure, followed by reaction at 8.3 kPa until the softening point shown in Table 1 was reached. The reaction mixture was cooled, solidified, and pulverized to obtain Composite Resin A-1.

[0082] Production Example 2 (Production method of composite resin A-2) The alcohol components and carboxylic acid components other than trimellitic acid shown in Table 1 were placed in a 10-liter four-neck flask equipped with a nitrogen inlet tube, dehydration tube, stirrer, and thermocouple, and heated to 160°C to dissolve. The bireactive monomer, polymerization initiator, and raw monomers for the vinyl polymer unit shown in Table 1 were added dropwise over 1 hour using a dropping funnel while maintaining the temperature in the bath at 160°C ± 3°C. Stirring was continued for 1 hour while maintaining the temperature at 160°C to polymerize the raw monomers for the vinyl polymer unit and the bireactive monomer. The mixture was then stirred at 8.3 kPa for 1 hour to remove unreacted monomers. An esterification catalyst was then added, the temperature was raised to 230°C, and the mixture was maintained for 6.5 hours. The reaction was then carried out at a reduced pressure of 8.3 kPa for 1 hour while maintaining the temperature at 230°C. Trimellitic acid was then added at 215°C, and the reaction was continued at 210°C and 40 kPa until the target softening point was reached. The reaction mixture was cooled, solidified, and pulverized to obtain Composite Resin A-2.

[0083] Production Examples 3 and 4 (Production of Composite Resins A-3 and A-4) Composite resins A-3 and A-4 were obtained in the same manner as in Production Example 2, except that the raw material monomers shown in Table 1 were used.

[0084] Production Example 5 (Production of Composite Resin AA-1) The alcohol monomer, acid monomer, tin(II) 2-ethylhexanoate, and gallic acid shown in Table 1 were added, heated to 235°C, and reacted for 10 hours at normal pressure, then further reacted at 8.3 kPa until the target softening point was reached. The reaction product was cooled, solidified, and pulverized to obtain composite resin AA-1.

[0085] [Table 1]

[0086] The wax components used were as follows: Paracol 6490: manufactured by Nippon Seiro Co., Ltd., molecular weight average 800, melting point 76°C, acid value 18mgKOH / g, hydroxyl value 97mgKOH / g Fischer-Tropsch Wax H105: manufactured by Sasol Wax, melting point 105°C

[0087] Example 1-1 200 g of straight asphalt (Associated Asphalt, Performance Grade (PG) 64-22) preheated to 180°C was weighed into a 300 mL stainless steel beaker, and 10 g (5 parts by mass per 100 parts by mass of asphalt) of the composite resin A-1 obtained in Production Example 1 was added thereto. The mixture was stirred at 180°C and 400 rpm for 2 hours to prepare asphalt composition (AS-1).

[0088] Examples 1-2 to 1-4, Comparative Examples 1-1 to 1-3 Asphalt compositions AS-2 to AS-4 and AS-C1 to AS-C3 were prepared in the same manner as in Example 1-1, except that the blending ratios were changed as shown in Table 2. In Comparative Examples 1-3, modified asphalt (Performance Grade (PG) 76-22, manufactured by Ergon Asphalt & Emulsions) was used as the asphalt.

[0089] [evaluation] [Storage stability test] The prepared asphalt composition was weighed out into two 4 oz glass bottles (Piramal Glass, manufactured by Piramal Glass USA Inc.), each weighing 100 g. After storing in a 180°C oven for 18 hours, the bottle was cooled to room temperature. The height of the polyester precipitate in the asphalt composition at this time was measured visually, and the measured amount of polyester precipitate was used as an index of storage stability. The smaller the amount of polyester precipitate, the better the storage stability of the asphalt composition. Asphalt compositions with excellent storage stability have less variation in asphalt strength when used in pavements. The results are shown in Table 2.

[0090] [Table 2]

[0091] Example 2-1 Of 150 g of asphalt, 4.5 g of composite resin A-1 obtained in Production Example 1, and 2500 g of aggregate, the aggregate was placed in a Hobart mixer and mixed at 180°C for 30 seconds. Asphalt was then added and mixed for 1 minute. Furthermore, asphalt modifier was added and mixed for 1 minute. After storing the resulting asphalt mixture at 180°C for 15 minutes, 1200 g of the mixture was filled into a formwork and compacted on both sides 75 times using an automatic asphalt compaction device (NA-507, manufactured by Nakajima Gihan Co., Ltd.), followed by cooling to room temperature over 15 hours to obtain an asphalt specimen. (aggregate) The aggregate used was manufactured by Blythe Construction Co., Ltd. 2500g of aggregate contained 625g of gravel (coarse aggregate), 1625g of screenings (fine aggregate), and 250g of pit sand (fine aggregate). The mass percentage of each component was as follows: Passed mass%: 〔gravel〕 Sieve size 9.50mm: 90.4% by mass Sieve size 8.00mm: 73.3% by mass Sieve size 4.75mm: 24.8% by mass Sieve size 2.80mm: 3.9% by mass Sieve size 1.00mm: 1.2% by mass Sieve size 0.50mm: 0.8% by mass [Screenings] Sieve size 9.50mm: 100.0% by mass Sieve size 8.00mm: 99.9% by mass Sieve size 4.75mm: 98.2% by mass Sieve size 2.80mm: 77.4% by mass Sieve size 1.00mm: 36.8% by mass Sieve size 0.50mm: 22.1% by mass [Mountain sand] Sieve size 9.50mm: 100.0% by mass Sieve size 8.00mm: 100.0% by mass Sieve size 4.75mm: 98.0% by mass Sieve size 2.80mm: 94.2% by mass Sieve size 1.00mm: 70.6% by mass Sieve size 0.50mm: 33.6% by mass

[0092] Examples 2-2 to 2-4, Comparative Examples 2-1 to 2-2 Except for changing the blending ratio as shown in Table 3, asphalt specimens were prepared in the same manner as in Example 2-1.

[0093] [evaluation] [Method for measuring void ratio] The theoretical density Gmm was measured using the asphalt mixture before compaction in accordance with AASHTO T209, as specified by the American Association of State Highway and Transportation Officials (AASHTO). In accordance with AASHTO T166, the asphalt mixture was compacted using an automatic compaction device to obtain an asphalt specimen. The bulk density Gmb of the asphalt specimen was calculated using the following formula: where D is the weight (g) of the specimen when dry, W is the weight (g) of the specimen when submerged, and S is the weight (g) of the specimen after wiping off any water droplets from the surface. Gmb=D / (SW)

[0094] The porosity Va (wt %) was calculated from the above-obtained Gmm and Gmb using the following formula: The average value and standard deviation of the three trial results are shown in Table 3. Va = {1-(Gmb / Gmm)} x 100

[0095] [Method for evaluating oil resistance of asphalt specimens] The asphalt specimen was immersed in kerosene (manufactured by Speedway) for 2 minutes. A 1-gallon oil-based round can was used as the immersion container, and a wire mesh stand approximately 1 cm high and 7 cm long and wide was placed at the bottom of the can, allowing the kerosene to thoroughly soak all surfaces of the specimen. After immersion for 2 minutes, the specimen was removed, the kerosene on the surface was wiped off with a paper towel, and the weight was measured. This weight was taken as Wa. After measuring the weight, the specimen was again immersed in kerosene for 24 hours. After 24 hours, the specimen was removed, the kerosene on the surface was wiped off with a paper towel, and the specimen was dried in air at room temperature (20°C) for another 24 hours before being weighed again. The weight at this time was taken as Wb. The weight loss rate, which is an index of oil resistance, was calculated using the following formula. The average and standard deviation of the results of three trials are shown in Table 3. Weight loss rate (%)=[(Wa-Wb) / Wa]×100 The smaller the weight loss rate, the better the oil resistance of the asphalt specimen.

[0096] Oil resistance was evaluated as an index of the strength of the asphalt specimen, especially strength unevenness. One known method for evaluating oil resistance is FAA P-404, a standard established by the U.S. Federal Aviation Administration (FAA) for oil-resistant asphalt pavements for airports. The standard requires a void content of 2.5±0.2% by weight. In contrast, dense-graded asphalt for general roads usually has a void ratio of 7.5±0.5% by weight. The evaluation results in this example are evaluation results corresponding to dense-graded asphalt for general roads. In this example, an asphalt specimen with a porosity of 7.5±0.5% by weight, which is higher than that specified by FAA P-404, was used to evaluate oil resistance under more severe conditions.

[0097] [Table 3]

[0098] Comparing the Examples and Comparative Examples, the asphalt compositions using the specific composite resins of the Examples exhibit superior storage stability at high temperatures compared to the asphalt compositions of the Comparative Examples, and when used in road paving, pavements with less variation in strength are obtained. Furthermore, asphalt specimens obtained from asphalt mixtures using the specific composite resins of the Examples exhibit superior oil resistance (low weight loss), and pavements with less variation in strength are obtained.

Claims

1. An asphalt composition comprising asphalt (A) and a composite resin (B), the composite resin (B) contains a structural unit derived from a bireactive monomer in which a polyester (b1) unit and a vinyl polymer (b2) unit are bonded via a covalent bond, the polyester (b1) unit contains a structural unit derived from an alcohol component and a structural unit derived from a carboxylic acid component, and the vinyl polymer (b2) unit contains a structural unit derived from styrene, the alcohol component comprises an alkylene oxide adduct of bisphenol A; the carboxylic acid component comprises an aromatic dicarboxylic acid; The asphalt composition, wherein the ambireactive monomer is acrylic acid.

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

3. The asphalt composition according to claim 1, wherein the vinyl polymer (b2) further contains a structural unit derived from a (meth)acrylic acid alkyl ester in which the alkyl group has 4 to 22 carbon atoms.

4. The asphalt composition according to claim 1, wherein the molar ratio of the vinyl polymer (b2) unit to the polyester (b1) unit [(b2) / (b1)] is 10 / 90 to 45 / 55.

5. The asphalt composition according to claim 1, wherein the SP value of the vinyl polymer (b2) is 9.5 to 10.

5.

6. The asphalt composition according to claim 1, wherein the glass transition temperature of the composite resin (B) is 40 to 100°C.

7. The asphalt composition according to claim 1, wherein the polydispersity [Mw / Mn] of the composite resin (B) is 4 to 25.

8. The asphalt composition according to claim 1, wherein the composite resin (B) has a hydroxyl value of 10 to 35 mg KOH / g.

9. The asphalt composition according to claim 1, wherein the softening point of the composite resin (B) is 95 to 130°C.

10. The asphalt composition according to claim 1, wherein the content of the asphalt (A) is 85 to 99.5 wt. %.

11. The asphalt composition according to claim 1, wherein the content of the composite resin (B) is 0.5 to 15 wt. %.

12. 2. The asphalt composition of claim 1, wherein the content of thermoplastic elastomer is ≦1% by mass.

13. An asphalt mixture comprising the asphalt composition of claim 1 and aggregate.

14. A method for producing an asphalt mixture, comprising: mixing asphalt (A) with a composite resin (B) to obtain an asphalt composition; and mixing the asphalt composition with heated aggregate, the composite resin (B) contains a structural unit derived from a bireactive monomer in which a polyester (b1) unit and a vinyl polymer (b2) unit are bonded via a covalent bond, the polyester (b1) unit contains a structural unit derived from an alcohol component and a structural unit derived from a carboxylic acid component, and the vinyl polymer (b2) unit contains a structural unit derived from styrene, the alcohol component comprises an alkylene oxide adduct of bisphenol A; the carboxylic acid component comprises an aromatic dicarboxylic acid; The method for producing an asphalt mixture, wherein the ambireactive monomer is acrylic acid.

15. A road paving method, comprising the step of applying the asphalt mixture according to claim 13 to a road to form an asphalt paving material layer.

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