JP2002121387A - Asphalt modifier and modified asphalt composition - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide an asphalt modifier which is possible to improve fluidity resistance of asphalt at a high temperature and bending characteristics thereof at a low temperature, and which has excellent mechanical stability, and excellent dispersion and solubility in the asphalt, and to provide a composition comprising compounding the modifier. SOLUTION: In the modifier for oily components-containing asphalt comprising a saturated content of 7-25% and an aromatic content of 65-80%, the asphalt modifier comprises, as a principal component, a conjugated diene type copolymer comprising (A) a conjugated diene unit of 55-99.9 wt.%, (B) an unsaturated carboxylic acid alkali metal salt unit of 0.1-5 wt.%, (C) an unsaturated carboxylic acid unit of 0-4.9 wt.%, and (D) an aromatic vinyl compound unit of 0-44.9 wt.%. The modified asphalt composition comprises adding the asphalt modifier of 0.2-20 wt.% in terms of a solid content to the oily components- containing asphalt.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

The present invention relates to a conjugated diene copolymer containing an alkali metal salt of an unsaturated carboxylic acid as a main component, which is added to asphalt which is oily at room temperature and contains a large amount of saturated or aromatic components. The present invention relates to an asphalt modifier which can improve the flow resistance at high temperatures and the bending characteristics at low temperatures of asphalt, and is excellent in mechanical stability and dispersibility and solubility in asphalt, and a composition containing the same.

[0002]

2. Description of the Related Art Bituminous materials such as asphalt and tar have waterproofness and antiseptic properties, and have been used for road paving materials, roofing materials, coating materials and the like since ancient times. In particular, asphalt is usually used as an asphalt mixture in which an appropriate amount of aggregate, filler and the like are mixed. However, such asphalt mixture has high temperature sensitivity, adhesiveness, It has disadvantages such as low abrasion resistance and impact resistance and poor low temperature characteristics. On the other hand, by blending a rubber component such as SBR (styrene butadiene copolymer latex) or CR (chloroprene rubber latex) or a thermoplastic elastomer such as SBS block copolymer into asphalt as a modifier, The modified asphalt mixture has an effect of decreasing the heat resistance, increasing the adhesion to the aggregate and the abrasion resistance, and improving the flexibility, and as a result, the high temperature characteristics and the low temperature characteristics are remarkably improved. Obtainable. These reforming effects can be attributed to the fact that when asphalt is separated by thin-layer chromatography and quantitatively analyzed by a flame ionization detector, the oil-saturated content is generally 4 to 6% and the aromatic content is generally at room temperature. In particular, it is known that 60-64% of asphalt produced from Middle Eastern crude oil is easy to obtain. However, asphalt produced from crude oil produced in China, India, Russia, etc., generally has a large amount of oily saturated and aromatic components at room temperature, and SB
It is known that even when a modifier such as R or SBS is added, it is difficult to obtain high-temperature fluid resistance and low-temperature bending characteristics.

[0003]

DISCLOSURE OF THE INVENTION The present invention has been made as a result of intensive studies to solve the above-mentioned problems of the prior art, and an object of the present invention is to provide a large amount of oily saturated or aromatic components at room temperature. An object of the present invention is to provide an asphalt modifier excellent in mechanical stability and excellent dispersibility and solubility in asphalt, and an asphalt composition containing the same, in order to improve the high-temperature flow resistance and low-temperature bending characteristics of asphalt.

[0004]

The present invention relates to a modifier for asphalt containing an oily component, comprising (A) 55 to 99.9% by weight of a conjugated diene unit and (B) an alkali unsaturated carboxylic acid. 0.1 to 5% by weight of a metal salt unit and 0 to 4.9% by weight of an unsaturated carboxylic acid unit (C) (provided that the total amount of (B) and (C) is 0.1 to 5% by weight). And (D) an asphalt modifier characterized by comprising a conjugated diene-based copolymer comprising from 0 to 44.9% by weight of an aromatic vinyl compound unit as a main component. Also,
Asphalt containing the oily component, when separated by thin-layer chromatography and quantitatively analyzed by a flame ionization detector, has a saturated content of 7 to 25% and / or an aromatic content of 65 to 80%. An object of the present invention is to provide the asphalt modifier as described above. Further, the present invention provides a modified asphalt composition obtained by adding the above-mentioned asphalt modifier to the asphalt containing the oil component described in the preceding section in a solid content of 0.2 to 20% by weight.

Hereinafter, the present invention will be described in detail. Hereinafter, “modified asphalt composition” means a composition obtained by kneading asphalt modifier and asphalt, and “modified asphalt mixture” refers to a mixture of asphalt modifier and asphalt together with aggregates and the like. Shall mean the mixture obtained. In the conjugated diene copolymer which is a main component of the asphalt modifier of the present invention, (A) the conjugated diene includes, for example, 1,3-butadiene, isoprene,
2,3-dimethyl-1,3-butadiene, 1,3-pentadiene, 2-methyl-1,3-pentadiene, 1,3
-Hexadiene, 1,3-heptadiene, 1,3-octadiene, 4,5-diethyl-1,3-octadiene,
Examples thereof include 3-butyl-1,3-octadiene and chloroprene. Among these conjugated dienes, 1,3-butadiene, isoprene, 1,3
-Pentadiene is preferred, and 1,3-butadiene is particularly preferred. The conjugated dienes can be used alone or as a mixture of two or more. The conjugated diene content in the conjugated diene-based copolymer in the present invention is 55%.
９９99.9% by weight, preferably 60-80% by weight. In this case, if the content of the conjugated diene is less than 55% by weight, the flexibility of the modified asphalt composition is reduced, and the tenacity, low-temperature elongation and the like are impaired. The mechanical stability of the diene copolymer latex, the dispersibility and solubility in asphalt, the toughness of the modified asphalt composition, the dynamic stability of the modified asphalt mixture, and the like are reduced. Examples of the unsaturated carboxylic acid (C) include acrylic acid, methacrylic acid, crotonic acid, α-chloroacrylic acid, maleic acid, fumaric acid, itaconic acid, citraconic acid, and mesaconic acid. Among these unsaturated carboxylic acids, acrylic acid, methacrylic acid and maleic acid are particularly preferred. The unsaturated carboxylic acids can be used alone or in combination of two or more. Examples of the alkali metal in the alkali metal salt of the unsaturated carboxylic acid (B) include lithium, sodium, and potassium. These unsaturated carboxylic acid alkali metal salts can be used alone or in combination of two or more.
The content of the alkali metal salt of unsaturated carboxylic acid in the conjugated diene copolymer in the present invention is 0.1 to 5% by weight, preferably 0.3 to 3% by weight, and the content of unsaturated carboxylic acid is The amount is between 0 and 4.9% by weight, preferably between 0 and 3% by weight. However, the total content of the unsaturated carboxylic acid alkali metal salt and the unsaturated carboxylic acid is 0.1 to 5% by weight. In this case, if the content of the alkali metal salt of unsaturated carboxylic acid is less than 0.1% by weight, the mechanical stability of the conjugated diene-based copolymer latex and the dispersibility and solubility in asphalt, the toughness of the modified asphalt composition and If the tenacity, the dynamic stability of the modified asphalt mixture, etc. are reduced, on the other hand, if it exceeds 5% by weight, the viscosity of the conjugated diene copolymer latex increases, and the dispersibility and solubility in asphalt, the modified asphalt composition Toughness and tenacity, and the dynamic stability of the modified asphalt mixture. The content of the saturated carboxylic acid is 4.
Even when the content exceeds 9% by weight, the viscosity of the conjugated diene copolymer latex becomes high, and the dispersibility and solubility in asphalt, the toughness and tenacity of the modified asphalt composition, the dynamic stability of the modified asphalt mixture, and the like are increased. descend. Examples of the aromatic vinyl compound (D) include styrene, α-methylstyrene, vinyltoluene, vinylxylene, ethylstyrene, pt-butylstyrene, monochlorostyrene, dichlorostyrene, monobromostyrene, dibromostyrene, , 1-diphenylstyrene, N, N-dimethyl-p-aminostyrene, N,
N-diethyl-p-aminostyrene, N, N-dimethyl-p-aminoethylstyrene, N, N-diethyl-p-
Examples thereof include aminoethylstyrene, divinylbenzene, vinylnaphthalene, and vinylpyridine. Of these aromatic vinyl compounds, styrene and α-styrene are particularly preferred. Further, the aromatic vinyl compound,
They can be used alone or in combination of two or more. The content of the aromatic vinyl compound in the conjugated diene copolymer in the present invention is 0 to 44.9% by weight, preferably 15 to 40% by weight. In this case, if the content of the aromatic vinyl compound exceeds 44.9% by weight, the flexibility of the modified asphalt composition is reduced, tenacity, low-temperature elongation, etc. are impaired, and the dynamics of the modified asphalt mixture are reduced. The target stability also decreases.

Furthermore, in the conjugated diene copolymer of the present invention, if desired, other than the above-mentioned conjugated diene, unsaturated carboxylic acid alkali metal salt, unsaturated carboxylic acid and aromatic vinyl compound, Other unsaturated monomers copolymerizable with the monomer, for example, methyl (meth) acrylate, ethyl (meth) acrylate, n-butyl (meth)
Acrylate, t-butyl (meth) acrylate, n-
Hexyl (meth) acrylate, 2-ethylhexyl (meth) acrylate, 2-hydroxyethyl (meth)
Acrylate, 2-hydroxypropyl (meth) acrylate, 3-hydroxypropyl (meth) acrylate, N, N-dimethylaminoethyl (meth) acrylate, N, N-diethylaminoethyl (meth) acrylate, glycidyl (meth) acrylate, etc. (Meth) acrylic esters; unsaturated amides or unsaturated imides such as (meth) acrylamide, N-methylol (meth) acrylamide, and maleimide; vinyl cyanide compounds such as (meth) acrylonitrile and vinylidene cyanide; More than one species may be copolymerized. The usage ratio of these other unsaturated monomers is usually
20% by weight or less. In the present invention, when the conjugated diene-based copolymer contains the other unsaturated monomer, the content of each unit of (A), (B), (C), (D) and (E) Means that the total content of the units (A) to (E) is 100
It means the content when it is expressed as% by weight.

The conjugated diene copolymer according to the present invention comprises:
It is preferably used in the form of a latex dispersed in water. As a method for producing such a conjugated diene-based copolymer latex, preferably, a predetermined amount of each of a conjugated diene and an unsaturated carboxylic acid is added, if necessary, to an unsaturated carboxylic acid alkali metal salt and / or an aromatic vinyl compound or another aromatic vinyl compound. By copolymerizing with the unsaturated monomer by a known emulsion polymerization method, neutralizing the carboxyl group in the copolymer latex with caustic during the polymerization and / or after the polymerization is completed, and adjusting the pH to 6 or more. Manufactured. In this case, if the pH is less than 6, a predetermined amount of the unsaturated carboxylic acid alkali metal salt cannot be contained in the obtained conjugated diene-based copolymer, and the mechanical stability and asphalt of the conjugated diene-based copolymer latex cannot be contained. Becomes insufficient in dispersibility and solubility, and the toughness and tenacity of the modified asphalt composition,
The dynamic stability of the modified asphalt mixture decreases. The conjugated diene-based copolymer latex in the present invention may contain a predetermined amount of each of a conjugated diene and an alkali metal salt of an unsaturated carboxylic acid, if necessary, and optionally an unsaturated carboxylic acid and / or an aromatic vinyl compound or another unsaturated vinyl compound. It can also be obtained by copolymerization with a saturated monomer by a known emulsion polymerization method. The emulsifier, polymerization initiator, chain transfer agent and the like used in the emulsion polymerization method are not particularly limited.Examples of the emulsifier include sodium sulfonate of oleic acid, sodium dodecylbenzenesulfonate, sodium lauryl sulfate, Examples thereof include one or more anionic emulsifiers such as sodium diphenyl ether disulfonate and sodium dialkyl succinate sulfonate, and fluorine surfactants. In the present invention, particularly excellent effects can be achieved by using sodium sulfonate of oleic acid as an emulsifier. The amount of the emulsifier to be used is generally 0.5 to 10% by weight, preferably 1 to 8% by weight, based on all monomer components. In this case, if the use amount of the emulsifier is less than 0.5% by weight, the polymerization stability of the latex may be reduced due to the formation of aggregates, which may hinder the production of the conjugated diene-based copolymer latex, On the other hand 10
If the amount exceeds the weight percentage, the toughness and tenacity of the modified asphalt composition tend to decrease. Examples of the polymerization initiator include inorganic polymerization initiators such as potassium persulfate, sodium persulfate, and ammonium persulfate; and hydropolymers such as benzene hydroperoxide, paramenthane hydroperoxide, cumene hydroperoxide, and t-butyl hydroperoxide. Peroxides,
Examples include organic polymerization initiators such as azo compounds such as azoisobutyronitrile and azobisisovaleronitrile. These polymerization initiators can be used alone or in combination of two or more. The amount of the polymerization initiator to be used is generally 0.03 to 2% by weight, preferably 0.05 to 1% by weight, based on all monomer components. Further, in order to promote emulsion polymerization, together with the polymerization initiator, sodium pyrobisulfite, sodium sulfite, sodium bisulfite, ferrous sulfate, glucose, sodium formaldehyde sulfoxylate, L-ascorbic acid and salts thereof and the like A reducing agent and a chelating agent such as glycine, alanine and sodium ethylenediaminetetraacetate can be used in combination. As the chain transfer agent, for example, α-styrene dimer, preferably α-styrene dimer containing at least 60% by weight of 2,4-diphenyl-4-methyl-1-pentene component, terpinolene, α-terpinene, γ
-Terpinene, dipentene, n-octyl mercaptan, n-dodecyl mercaptan, t-dodecyl mercaptan, n-hexadecyl mercaptan, dimethyl xangen disulfide, diethyl xangen disulfide,
Examples thereof include diisopropylxangen disulfide, tetramethylthiuram disulfide, tetraethylthiuram disulfide, tetrabutylthiuram disulfide, dipentamethylenethiuram disulfide, and the like.
These chain transfer agents can be used alone or in combination of two or more. The amount of the chain transfer agent to be used is generally 0.01 to 5% by weight, preferably 0.03 to 1% by weight, based on all monomer components. For emulsion polymerization,
In addition to the emulsifier, polymerization initiator, chain transfer agent, if necessary, various electrolytes, a pH adjuster, and the like are used in combination, and for a total of 100 parts by weight of the monomer components, for example, water is usually used.
The polymerization temperature is usually 10 to 300 parts by weight.
To 80 ° C, preferably 30 to 60 ° C, usually 15 to
Polymerize for 40 hours. The method of adding each monomer at the time of emulsion polymerization may be any of a batch addition method, a division addition method, and a continuous addition method, or may be added by emulsifying a part or all of the monomer components in advance. Alternatively, these methods may be combined.

The conjugated diene copolymer latex produced in this manner usually has a viscosity of 10 to 1,000.
mPa · s, preferably 20 to 500 mPa · s, and the solid content is usually 40 to 70% by weight, preferably 45 to 60% by weight. The average particle size of the conjugated diene-based copolymer latex is usually 60 to 300 nm,
Preferably it is 80 to 200 nm. In this case, if the average particle diameter is less than 60 nm, the viscosity of the conjugated diene-based copolymer latex increases and handling becomes difficult, and the dispersibility and solubility in asphalt also tends to decrease. Dispersion on asphalt
Solubility tends to decrease. Here, the average particle diameter is a value calculated by a measurement method described later. The average particle diameter of the conjugated diene copolymer latex can be easily adjusted to the target value by appropriately combining the conditions such as the amount of water, emulsifier or polymerization initiator used during emulsion polymerization, and the polymerization temperature. can do. The conjugated diene copolymer latex has a gel content of usually 0.1 to 80% by weight, preferably 0.1 to 50% by weight, and more preferably 0.1 to 30% by weight. In this case, if the gel content is less than 0.1% by weight, the toughness and tenacity of the modified asphalt composition tends to decrease, while
If the content is more than 100% by weight, the dispersibility and solubility in asphalt tends to decrease. In addition, the gel content referred to herein is a toluene-insoluble content determined by a measurement method described later. The gel content of the conjugated diene-based copolymer latex can be easily adjusted to a target value by appropriately selecting the type and amount of a chain transfer agent that acts as a molecular weight modifier during emulsion polymerization, and The amount of the polymerization initiator at the time of the emulsion polymerization, it can also be adjusted by the polymerization temperature and the like,
It is preferable to combine these conditions appropriately. The conjugated diene-based copolymer in the present invention has a Mooney viscosity (ML _{1 + 4} , 100 ° C .; the same applies hereinafter) when used as a solid rubber.
Usually, it is 50 to 200, preferably 80 to 180.
In this case, if the Mooney viscosity is less than 50, the toughness and tenacity of the modified asphalt composition tends to decrease, while if it exceeds 200, the dispersibility and solubility in asphalt tends to decrease. The Mooney viscosity of the conjugated diene copolymer can be easily adjusted to a target value by appropriately combining conditions such as the type and amount of the chain transfer agent during the emulsion polymerization and the amount of the polymerization initiator. it can. The asphalt modifier of the present invention can be used by mixing a plurality of conjugated diene-based copolymers. The asphalt modifier of the present invention may be modified with other SBR latex, CR latex, SBS emulsion, etc. within the range that does not impair the performance of the intended modified asphalt composition, modified asphalt mixture or asphalt modifier itself. It is possible to mix and use materials. The conjugated diene-based copolymer that is the main component of the asphalt modifier of the present invention is preferably used as a latex produced by the emulsion polymerization. It can be recovered by salting out and coagulation and used as a crumb-like or powdery solid rubber. The asphalt modifier of the present invention, if necessary, a dispersant, a stabilizer, an antioxidant, an ultraviolet absorber, an anti-peeling agent, a preservative,
An antifoaming agent and the like, and a protective colloid such as sodium polyacrylate, polyvinyl alcohol, casein, gelatin, carboxymethyl cellulose, and hydroxyethyl cellulose can also be added.

[0009] The asphalt modifier of the present invention may be a modified asphalt composition kneaded with the following specific asphalt, or may further contain, in addition to aggregate, a filler,
It is used as a modified asphalt mixture containing a reinforcing material and the like. As the asphalt to which the asphalt modifier of the present invention is applied, when the asphalt is separated by thin-layer chromatography and quantitatively analyzed by a flame ionization detector, the saturated content is 7 to 25% and / or aromatic 6 minutes
Examples thereof include petroleum asphalt containing 5 to 80% of oily components at room temperature and mixed asphalt in which natural asphalt and regenerated asphalt are mixed in the above component range. As an apparatus for separating asphalt by thin-layer chromatography and quantitatively analyzing it with a flame ionization detector, Iatroscan MK-5 manufactured by Yatron Corporation can be used. Examples of the petroleum asphalt include straight asphalt of various penetration grades obtained by distillation of crude oil, blown asphalt and semi-manufactured by blowing these straight asphalts in the presence or absence of a catalyst. Examples include blown asphalt and solvent deasphalted asphalt obtained by separating a petroleum fraction containing asphalt with a solvent such as propane or butane. These petroleum asphalts can be used alone or in combination of two or more. Examples of the natural asphalt include Gilsonite, Glance Pitch, Grahamite, Trinidad Lake Asphalt and the like. These natural asphalts can be used alone or in combination of two or more. The recycled asphalt is obtained, for example, from used asphalt-based road pavement. When using such a recycled asphalt, along with the asphalt modifier of the present invention, additives for regeneration, such as aromatic oils, naphthenic oils, paraffin oils, etc.
It is preferable to use a single compound or a combination of two or more compounds. Among these asphalts, the most preferred asphalt is straight asphalt, and in particular, straight asphalt having a 25 ° C penetration of 40 to 150, preferably 60 to 120 is preferable. The amount used when kneading the asphalt modifier of the present invention with asphalt varies depending on the purpose of use of the resulting modified asphalt composition or modified asphalt mixture.For example, in the case of a road pavement, asphalt 100 parts by weight The solid content is usually 0.2 to 20 parts by weight, preferably 1 to 10 parts by weight. When preparing a modified asphalt composition or a modified asphalt mixture using the asphalt modifier of the present invention, a suitable plant, for example, a plant for producing a heated asphalt mixture for road pavement, optionally aggregates, fillers A suitable amount of asphalt modifier is added to the asphalt mixed with the above and kneaded sufficiently. In this case, for example, after kneading the asphalt modifier, asphalt, aggregate, and the like, and then adding a solvent such as kerosene, a room temperature modified asphalt mixture for road pavement can be obtained. In addition, (b) asphalt and aggregates are added to an asphalt mixture having a relatively low temperature, for example, an aggregate temperature of 80 to 120 ° C., and an asphalt modifier and, if necessary, a foaming additive are added and kneaded. A semi-heat-modified asphalt mixture for road paving can be obtained. Further, (c) a heat-modified asphalt mixture for road paving by adding and kneading an asphalt modifier to an asphalt mixture obtained by mixing aggregate and the like at a temperature exceeding 120 ° C. in the same manner as a general heated asphalt mixture. Can be obtained. Although the effects of the present invention are sufficiently exhibited by any of these methods, it is particularly preferable in the case of the heating and kneading method (c) in that the effects of the present invention can be most achieved. The modified asphalt composition or the modified asphalt mixture using the asphalt modifying material of the present invention is useful as a roofing material, a covering material, a waterproof / waterproof material, a sealing material, a vibration damping material, and the like, in addition to a road pavement material. is there.

[0010]

DESCRIPTION OF THE PREFERRED EMBODIMENTS The embodiments of the present invention will be specifically described below with reference to examples. However, the present invention is not limited to these embodiments. Parts and% in Examples and Comparative Examples are based on weight unless otherwise specified.

EXAMPLES Examples 1 to 9 and Comparative Examples 1 to 7 Straight asphalt The compositions of the straight asphalts (AS-1 to AS-5 and standard AS) used in Examples 1 to 9 and Comparative Examples 1 to 7 were as follows: Table 1 shows the results measured by Iatroscan MK-5 manufactured by Yatron Co., Ltd. The standard asphalt used was a straight asphalt having a penetration of 60 to 80 manufactured by Mitsubishi Nisseki Co., Ltd. The copolymer latex monomer composition was as shown in Table 2 (Examples 1 to 9) and Table 3 (Comparative Examples 1 to 5), and each copolymer was prepared by an emulsion polymerization method using an autoclave having an internal volume of 100 liters. A polymer latex was prepared. The properties of each of the obtained copolymer latexes were measured and evaluated as follows. Average particle size: Otsuka Electronics Co., Ltd.
It was measured by using a laser particle size analysis system LPA-3100 manufactured by KK. Gel content: A dry film (a milligram) formed from each copolymer latex was immersed in 100 ml of toluene at 50 ° C. for 2 hours under stirring, and then dried.
The mixture was filtered using a 0 mesh wire mesh. Then, a part (c milliliter) of the filtrate is accurately collected and evaporated to dryness.
The obtained residual solid content (b milligram) was weighed and measured by the following equation. Gel content (%) = {[(ab) × (100 / c)] / a} × 100 Mooney viscosity: A copolymer was recovered from each copolymer latex and measured according to JIS K6387. Mechanical stability: JIS K63 by Malon type testing machine
The evaluation was carried out in accordance with No. 87. SBS block copolymer: SB in Table 3 (Comparative Examples 6, 7)
For S, TR2601C manufactured by JSR Corporation was used. The amount added to asphalt was 4%.

Modified Asphalt Composition Using the compounding recipe shown in Table 2 (Examples 1 to 9) and Table 3 (Comparative Examples 1 to 5), a modifier was added to each asphalt in a solid content of 4%. With a stirrer equipped with a single blade stirring blade, 1
Each modified asphalt composition was prepared by kneading at 70 ° C. and a rotation speed of 400 to 500 rpm. Using the formulation shown in Table 3 (Comparative Examples 6 and 7), 300 g of each asphalt was mixed with a homomixer (manufactured by Tokushu Kika Kogyo Co., Ltd.).
Each of the modified asphalt compositions was prepared by kneading the crumb-like SBS while stirring at 70 ° C. and a rotation speed of 3000 rpm. For each of the obtained modified asphalt compositions, the appearance after kneading was visually observed, and the dispersibility and solubility of each copolymer latex in asphalt was determined by the following 3 methods.
It was evaluated on a scale. Excellent (O): Uniformly dispersed or dissolved within 30 minutes, Normal (△): Uniformly dispersed or dissolved within 30 minutes and within 1 hour, Poor (X): Mixing for more than 1 hour Physical properties other than the dispersibility / solubility described above were evaluated in accordance with the method described in “Pavement Test Method Handbook” (November 10, 1988, published by The Japan Road Association). did. Table 4 shows asphalt properties of the straight asphalt used for the evaluation. Modified asphalt mixture “Asphalt Pavement Summary” (June 20, 1994, 6th
Plate, issued by the Japan Road Association) according to the dense grain asphalt mixture (20), 21% crushed stone, 25% 6th crushed stone, 13% 7th crushed stone, 6% screenings, 19% coarse sand, A modified asphalt composition in which an asphalt composition composed of 12% of fine sand and 4% of stone powder is used, and 100% of this asphalt is added to each asphalt with a modifier of 4% in solid content. 6%, mix at 170-180 ° C,
Each modified asphalt mixture was prepared. Each of the obtained modified asphalt mixtures was compacted by a roller compactor to prepare a test specimen, which was prepared in a “Handbook of Paving Test Methods” (Showa 6
The high-temperature dynamic stability (flow resistance) and the low-temperature bending characteristics were evaluated based on the wheel tracking test method and the bending test method described on November 10, 3rd, published by The Japan Road Association. Table 4 shows the mixture performance of the used straight asphalt.

Evaluation Results The asphalt modifier comprising the conjugated diene copolymer of the present invention has high mechanical stability as a latex and high dispersibility and solubility in asphalt, and has an oily saturated or aromatic content at room temperature. Even in the case of asphalt containing a large amount of asphalt, the toughness and tenacity of the modified asphalt composition, the low-temperature elongation and the viscosity at 60 ° C. were excellent, and the high-temperature dynamic stability and the low-temperature bending properties of the modified asphalt mixture were also excellent. On the other hand, in Comparative Examples 1 to 5, the toughness and tenacity of the modified asphalt composition were inferior, the viscosity at 60 ° C. was low, and the dynamic stability and low-temperature bending characteristics of the modified asphalt mixture were inferior. In Comparative Examples 6 and 7, the toughness and tenacity of the modified asphalt composition were inferior, the viscosity at 60 ° C. was low, and the dynamic stability and low-temperature bending characteristics of the modified asphalt mixture were also inferior. Table 2 (Examples 1 to 9) and Table 3 (Comparative Examples 1 to 7,
Reference examples) are shown together.

[0013]

[Table 1]

[0014]

[Table 2]

[0015]

[Table 3]

[0016]

[Table 4]

[0017]

The asphalt modifier of the present invention, as a latex, has low viscosity and good handleability, excellent mechanical stability and excellent dispersibility and solubility in asphalt, and has an oily saturated or aromatic content at room temperature. When the modified asphalt composition is added to asphalt with a large content, it has a large toughness and tenacity with respect to the aggregate, has a high viscosity at 60 ° C., has a low temperature sensitivity, and has a modified asphalt mixture. It has high dynamic stability, excellent flow resistance and excellent low temperature bending properties. Therefore, the asphalt modifier of the present invention effectively modifies asphalt containing a large amount of oil-saturated or aromatic components at room temperature, which has conventionally been difficult to obtain high-temperature characteristics and low-temperature characteristics. It has characteristics that can effectively prevent "rudge digging" and "cracking" of road pavement materials, and also contributes to expanding the use of asphalt compositions for new applications, improving productivity and reducing costs. is there.

Continued on the front page F-term (reference) 4J002 AC023 AC083 AC093 AC103 AE05X AG00W GL00 4J100 AB00S AB02S AB03S AB04S AB07S AB08S AB09S AB13S AB16S AJ01Q AJ02Q AJ03Q AJ08Q AJ09Q AK08S04A03 AS03 AS04 AS03 AS03 AS03 AS04 AS01 JA67

Claims (3)

[Claims] 1. A modifier for asphalt containing an oily component, comprising: (A) 55 to 99.9% by weight of a conjugated diene unit;
1 to 5% by weight, (C) 0 to 4.9 unsaturated carboxylic acid units
% (Provided that the total amount of (B) and (C) is 0.1 to 5% by weight) and (D) aromatic vinyl compound unit 0
An asphalt modifier characterized by comprising a conjugated diene-based copolymer consisting of up to 44.9% by weight as a main component. 2. Asphalt containing an oily component, when it is separated by thin-layer chromatography and quantitatively analyzed by a flame ionization detector, the saturated content is reduced to 7 to 25% and / or the aromatic content is reduced. The asphalt modifier according to claim 1, which contains 65 to 80%. 3. The asphalt modifier according to claim 1,
For asphalt containing the oil component described in the preceding paragraph,
A modified asphalt composition containing 0.2 to 20% by weight of solid content.