Light-colored binder composition

Abstract

[Problem] To provide a light-colored binder composition that makes it possible to improve weather resistance, workability, and durability while suppressing adhesion / peeling properties with respect to a tire. [Solution] The present invention is characterized by comprising a petroleum-based solvent extract oil, a petroleum resin, 1.6-2.8 wt% of a thermoplastic elastomer, 3.5-6.0 wt% of an ethylene copolymer, and 0.4-0.99 wt% of FT wax.

Description

Light-colored binder composition

[0001] The present invention relates to a colorable bright-color binder composition for use in road paving and the like, and particularly to a bright-color binder composition that is suitable for improving weather resistance, workability, and durability while suppressing adhesion to and peeling from tires.

[0002] For road paving in areas where scenery is important, such as parks and tourist spots, a colorable binder called a light-colored binder is often used instead of the typical black asphalt binder. Light-colored binders are an asphalt binder substitute made from a mixture of petroleum resin, rubber, elastomer, and heavy petroleum oil. Because they have a bright hue and high transparency, they can be colored with pigments or road paving that makes use of the texture of the aggregate.

[0003] Such light-colored binders have traditionally been improved in terms of weather resistance and workability. Weather resistance has been improved by incorporating polymers that are resistant to UV degradation. Workability is particularly affected by the binder's adhesion to the rake, which causes stringing when the binder mixture is applied by hand using a rake. For this reason, efforts have traditionally been made to suppress stringing and improve workability by selecting the optimal polymer to be mixed into the binder. Furthermore, light-colored paving binder compositions have been proposed that reduce the polymer content to prevent stringing during paving and add ethylene ethyl acrylate (EEA) to maintain durability (see, for example, Patent Document 1).

[0004] JP 2017-88643 A

[0005] Light-colored pavements using such light-colored binders are often applied in areas with relatively low traffic, such as parks and tourist spots. Meanwhile, in recent years, light-colored binders have increasingly been used to improve the visibility of road surfaces inside tunnels, etc. Because the traffic inside such tunnels is heavy, when light-colored binders are used there, durability that can withstand the force of passing vehicles is also important. To improve the durability of conventional light-colored binders, it is conceivable to increase the amount of polymer added.

[0006] However, while simply increasing the amount of polymer added to conventional light-colored binders can improve durability, the increased amount of polymer can cause the mixture containing the light-colored binder and aggregate to adhere to tires, increasing the likelihood of the pavement adhering to the tires peeling off as the vehicle moves. This is because the affinity of the binder surface for tires increases with the increased amount of polymer. When this peeling occurs, the pavement surface is scraped and loses its flatness, leading to early deterioration of the pavement from the damaged areas, and improvements were needed.

[0007] Therefore, the present invention has been devised in consideration of the above-mentioned problems, and an object of the present invention is to provide a bright color binder composition that can improve weather resistance, workability, and durability, and can also suppress adhesion to and peeling from tires.

[0008] The bright color binder composition according to the first aspect of the present invention is characterized by containing a petroleum-based solvent-extracted oil, a petroleum resin, a thermoplastic elastomer in an amount of 1.6% by weight or more and 2.8% by weight or less, an ethylene copolymer in an amount of 3.5% by weight or more and 6.0% by weight or less, and an FT wax in an amount of 0.4% by weight or more and 0.99% by weight or less.

[0009] A bright color binder composition according to a second invention is the bright color binder composition according to the first invention, characterized in that the thermoplastic elastomer is SEBS having a styrene content of 25.0% or more and 35.0% or less, and the ethylene copolymer is one or both of a methacrylate copolymer and an acrylate copolymer.

[0010] A light color binder composition according to a third invention is the same as that of the second invention, wherein the methacrylate copolymer is ethylene methyl methacrylate (EMMA) and the acrylate copolymer is ethylene ethyl acrylate (EEA).

[0011] A bright color binder composition according to a fourth aspect of the present invention is the bright color binder composition according to the third aspect of the present invention, characterized in that the EMMA has a methyl methacrylate (MMA) content of 10.0% or more and 20.0% or less and a melt mass-flow rate (MFR) of 0.2 g / 10 min or more and 1.0 g / 10 min or less, and the EEA has an EA content of 10.0% or more and 20.0% or less and an MFR of 0.2 g / 10 min or more and 1.0 g / 10 min or less.

[0012] The bright color binder composition according to a fifth aspect of the present invention is the bright color binder composition according to any one of the first to fourth aspects of the present invention, characterized in that the bright color binder composition contains an anti-stripping agent.

[0013] The bright color binder composition according to a sixth aspect of the present invention is the bright color binder composition according to the fifth aspect of the present invention, characterized in that the anti-stripping agent is a dimer acid, and the content thereof is 0.2% by weight or more and 2.0% by weight or less based on the total weight of the composition.

[0014] The light color binder composition according to the seventh invention is characterized by containing the light color binder composition according to any one of the first to sixth inventions and aggregate.

[0015] According to the present invention having the above-mentioned configuration, all of the compositions have a penetration (25°C) of 40 (0.1 mm) or more and 70 (0.1 mm) or less, a softening point of 56°C or more, a viscosity (180°C) of 800 mPa·s or less, a DS (index for measuring the strength of road pavement) of 1000 times / mm or more, adhesion / detachment of 50% or less, and no stringiness was observed in any of the compositions. Therefore, it is possible to provide a bright-colored binder composition that can improve weather resistance, workability, and durability while suppressing adhesion / detachment to tires.

[0016] Fig. 1 is a diagram for explaining the details of the DS measurement method, and Fig. 2 is a diagram showing an example of the subsidence amount (mm) versus test time (minutes) when the DS measurement test start time is used as the starting point.

[0017] The light color binder composition according to an embodiment of the present invention will be described in detail below.

[0018] In order to solve the above-mentioned problems, the present inventors have invented a bright-color binder composition that can improve weather resistance, application ease, and durability and can suppress adhesion to and peeling from tires by adding appropriate amounts of SEBS, EMMA or EEA, and FT wax, and, if necessary, adding an appropriate amount of an anti-stripping agent.

[0019] The bright color binder composition according to the present invention contains a petroleum-based solvent-extracted oil, a petroleum resin, a thermoplastic elastomer (1.6% by weight or more and 2.8% by weight or less), an ethylene copolymer (3.5% by weight or more and 6.0% by weight or less), and an FT wax (0.4% by weight or more and 0.99% by weight or less).

[0020] The component composition of the light-colored binder composition to which the present invention is applied and the reasons for limiting the components will be explained below.

[0021] Petroleum-based solvent-extracted oil is an extracted oil produced in the solvent extraction process when producing lubricating oil from crude oil, and is an oily substance rich in aromatics and naphthenes (see "How Petroleum Products Are Made," Figure 3-1 "General Lubricating Oil Manufacturing Process," published by the Petroleum Association of Japan, April 1998, p. 97, and "New Petroleum Dictionary," edited by the Japan Petroleum Institute, 1982, p. 304). This petroleum-based solvent-extracted oil is a component that acts as a softener when added to a binder composition, and has a boiling point of 350°C or higher and a kinematic viscosity at 60°C of 300mm. 2 / s or more 800mm 2 / s or less, a flash point of 250°C or more, and an aromatic content of 65% or more.

[0022] Examples of such petroleum-based solvent-extracted oils include bright stock solvent extracts extracted with solvents such as phenol, N-methylpyrrolidone, liquid sulfur dioxide, and furfural during the crude oil refining process. From the perspective of achieving good workability and rutting resistance, the content of this petroleum-based solvent-extracted oil is desirably 40% by weight to 80% by weight, 45% by weight to 75% by weight, or 50% by weight to 70% by weight, based on the total weight of the bright-colored binder composition. By keeping the content of the petroleum-based solvent-extracted oil within the above-mentioned range, the binder does not become too soft, improving its flow resistance (rutting resistance). Furthermore, the binder's viscosity does not become too high, making it suitable for application.

[0023] Petroleum Resins Petroleum resins are polymers of decomposition products produced when naphtha is thermally decomposed to produce ethylene, propylene, and the like. Those with a high content of cyclopentadiene (CPD) or dicyclopentadiene (DCPD) have a high softening point. Petroleum resins have a molecular weight of approximately 200 to 2000, generally 1000 to 1500, a softening point of 100°C to 150°C, and are colorless to pale yellow resins. From the perspective of achieving good workability, the content of this petroleum resin is preferably 10% by weight to 50% by weight, 15% by weight to 45% by weight, or even 20% by weight to 40% by weight.

[0024] By setting the content of the petroleum resin within the above range, the viscosity can be optimized, thereby further improving the workability and preventing a further decrease in the resistance to flow.

[0025] Thermoplastic elastomer: 1.6 wt% to 2.8 wt%. The content of this thermoplastic elastomer is 2 wt% to 2.8 wt% based on the total weight of the light-colored binder composition. If the thermoplastic elastomer content exceeds 2.8 wt%, stringiness occurs when the light-colored binder is handled if its temperature drops below approximately 120-130°C. This stringiness refers to a condition in which the binder becomes viscous and stretches into threads upon contact. Furthermore, if the thermoplastic elastomer content exceeds 2.8 wt%, the binder surface has high affinity for tires, resulting in poor adhesion and peelability. Therefore, in the present invention, by limiting the thermoplastic elastomer content to 2.8 wt% or less, stringiness during application is suppressed and a significant decrease in application performance is prevented. If the thermoplastic elastomer content is less than 1.6 wt%, the effect of preventing brittle fracture due to curing cannot be achieved, resulting in reduced dynamic stability (DS).

[0026] Therefore, the content of the thermoplastic elastomer is set to 1.6 wt % or more and 2.8 wt % or less, more preferably 2.0 wt % or more and 2.8 wt % or less, even more preferably 2.3 wt % or more and 2.7 wt % or less, and particularly preferably 2.4 wt % or more and 2.6 wt % or less, based on the total weight of the light color binder composition.

[0027] In the present invention, any thermoplastic elastomer may be added, but the addition of SEBS is particularly desirable. SEBS is obtained by completely hydrogenating the butadiene block in a styrene-butadiene-styrene block copolymer (SBS) to eliminate double bonds, resulting in significantly improved heat resistance and weather resistance compared to SBS. However, because this hydrogenation treatment changes the flexibility of the molecular chain, the effect of adding SEBS to an asphalt binder composition differs from that of SBS.

[0028] The SEBS preferably has a styrene content in the range of 25% to 35%, more preferably 28% to 33%.

[0029] SEBS having the above-described physical properties can be configured to have excellent elasticity, and by adding this to the light-colored binder composition of the present invention, it is possible to achieve both an improvement in DS, which is an index for measuring the strength of road pavement, and prevention of brittle fracture due to hardening.

[0030] Ethylene copolymer: 3.5 wt% to 6.0 wt% The ethylene copolymer content is 3.5 wt% to 6.0 wt% based on the total weight of the light-colored binder composition. If the ethylene copolymer content is less than 3.5 wt%, the DS decreases, adhesion / release properties deteriorate, and stringiness occurs during application. If the ethylene copolymer content exceeds 6.0 wt%, adhesion / release properties deteriorate.

[0031] In the present invention, the ethylene copolymer may be either one or both of a methacrylate copolymer and an acrylate copolymer. The methacrylate copolymer may be ethylene methyl methacrylate (EMMA), and the acrylate copolymer may be ethylene ethyl acrylate (EEA).

[0032] For example, any ethylene copolymer such as ethylene-acrylic acid resin (EAA) or modified ethylene-vinyl acetate copolymer (modified EVA) may be added, but it is particularly desirable to add one or both of EMMA and EEA.

[0033] EMMA is a thermoplastic resin that is a copolymer of ethylene and methyl methacrylate, and has high flexibility and transparency. By using EMMA with a methyl methacrylate (MMA) content of 10% to 20% and a melt mass-flow rate (MFR) of 0.2 g / 10 min to 1.0 g / 10 min, the decrease in flexibility of the binder composition due to an increase in viscosity can be suppressed, and the increase in viscosity can be suppressed, thereby preventing a decrease in DS. By setting the EMMA content to 3.5 wt% to 6.0 wt% based on the total weight of the light-color binder composition, the DS can be improved, deterioration of adhesion / detachment properties can be prevented, and stringiness during application can be prevented.

[0034] EMMA may also be substituted with ethylene ethyl acrylate (EEA). The EEA, like EMMA, is limited by its EA content and MFR. The EEA substituted for EMMA has an EA content of 10% to 20% and an MFR of 0.2 g / 10 min to 1.0 g / 10 min. By setting the EEA content to 3.5 wt% to 6.0 wt% based on the total weight of the light-color binder composition, the DS can be improved, deterioration of adhesion / detachment properties can be prevented, and stringiness during application can be prevented.

[0035] The content of EMMA and EEA is preferably in the range of 3.5% by weight or more and 6.0% by weight or less, but in order to achieve the above-mentioned effects, it may be more preferably in the range of 3.5% by weight or more and 5.0% by weight or less, and even more preferably in the range of 4.0% by weight or more and 4.5% by weight or less.

[0036] FT wax: 0.4 wt% or more and 0.99 wt% or less. FT wax is a wax made from long-chain linear hydrocarbons produced by the Fischer-Tropsch process. This wax is solid at room temperature and normal pressure and has a high melting point and low viscosity. That is, the viscosity of FT wax is significantly lower than that of general waxes. It also has high heat resistance and abrasion resistance, and is excellent in waterproofing and protection. FT waxes with a melting point of 100°C or higher are preferred. Using a wax with a low melting point is thought to affect binder properties. In the present invention, FT wax is localized on the binder surface and reduces the adhesion between the binder and the rubber tire, thereby improving adhesion and release properties. While other waxes such as paraffin wax and polyethylene-based waxes are also available, FT wax is preferred due to compatibility issues.

[0037] The FT wax content is 0.4 wt % or more and 0.99 wt % or less based on the total weight of the binder composition. If the FT wax content is less than 0.4 wt %, the effect of reducing the adhesion between the binder and the rubber tire described above cannot be obtained, and adhesion / detachment properties deteriorate. If the FT wax content exceeds 0.99 wt %, there is no correlation between toughness in the low temperature range and a decrease in DS, so adding excessive wax makes it impossible to maintain the uniformity of the binder components, causing a decrease in DS.

[0038] Anti-stripping Agent In the present invention, it is preferable to add an anti-stripping agent to prevent peeling between the light-colored binder composition and the aggregate. Dimer acid can be suitably used as the anti-stripping agent, and this dimer acid is produced by polymerization of C18 unsaturated fatty acid derived from vegetable oils and fats. By including this dimer acid in the binder composition, it acts to prevent peeling from the aggregate when mixed with the binder composition. In the present invention, dimer acid is used as a preferred anti-stripping agent, but the present invention is not limited to this.

[0039] As the anti-stripping agent, a resin acid may be used in addition to the dimer acid.

[0040] Resin acid is a polycyclic diterpene having 20 carbon atoms and a carboxyl group, and is a rosin containing one or more of abietic acid, dehydroabietic acid, neoabietic acid, pimaric acid, isopimaric acid, and palustric acid.

[0041] Examples of rosin used herein include gum rosin, wood rosin, and tall oil rosin. These rosins can be classified as gum rosin, wood rosin, and the like depending on their origin, raw materials, and extraction method. However, they are generally obtained as the residue component of steam distillation of pine resin. This rosin is a mixture containing abietic acid, palustric acid, neoabietic acid, dehydroabietic acid, pimaric acid, sandaracopimaric acid, isopimaric acid, and the like. This rosin typically softens at approximately 80°C and melts between 90°C and 100°C. Rosin contains various resin acids, such as abietic acid, dehydroabietic acid, dihydroabietic acid, tetrahydroabietic acid, palustric acid, neoabietic acid, and levopimaric acid. These resin acids may be purified and used individually.

[0042] In the present invention, the addition of an anti-stripping agent is not essential, and its content may be 0.0 wt % based on the total weight of the light color binder composition. However, if an anti-stripping agent is added, it is desirable to add it in an amount of 0.2 wt % to 2.0 wt % based on the total weight of the light color binder composition. If the content of this anti-stripping agent is 0.2 wt % or more, peeling when mixed with aggregate can be prevented, and the stability of the final binder composition can be further improved. On the other hand, if the content of this anti-stripping agent exceeds 2.0 wt %, not only will the stability improvement effect saturate, but the increased amount of expensive anti-stripping agent will significantly increase raw material costs. In other words, adding an anti-stripping agent in an amount exceeding 2.0 wt % will not significantly improve stability and will actually be disadvantageous in terms of raw material costs.

[0043] The anti-stripping agent is preferably contained in an amount of 0.2% by weight to 1.0% by weight based on the total weight of the binder composition. By setting the upper limit of the anti-stripping agent content at 1.0% by weight, it is possible to improve the stability of the binder composition while minimizing increases in raw material costs, thereby improving cost-effectiveness.

[0044] The anti-stripping agent is preferably contained in an amount of 0.3% by weight to 0.9% by weight, more preferably 0.4% by weight to 0.6% by weight, based on the total weight of the binder composition.

[0045] An asphalt pavement material containing the light-colored binder composition having the above-described composition and aggregate is formed. It is known that the light-colored binder content of the mixture types presented in the Pavement Design and Construction Guidelines is 3.5% by weight or more and 9.0% by weight or less based on the total amount of the asphalt pavement material. Therefore, in the present invention, the light-colored binder content may be 3.5% by weight or more and 9.0% by weight or less based on the total amount of the asphalt pavement material, but is not limited to this range.

[0046] The present invention will be described in detail below with reference to the test methods, examples, and comparative examples used in the present invention, but the present invention is not limited to these examples. In the following examples, when only % is given, it means % by weight.

[0047] In the present invention, samples of examples and comparative examples were prepared for experimental investigation. These samples were prepared by melting petroleum-based solvent-extracted oil at approximately 180°C, adding a predetermined amount of the above-mentioned SEBS, and then adding the above-mentioned petroleum resin, EMMA or EEA, FT wax, and dimer acid in the above-mentioned blending ratios. Mixing was performed using a homomixer or propeller mixer, and mixing and stirring were performed for approximately 3 to 4 hours at a rotation speed of 2000 to 3500 rpm. The temperature of the binder composition at the end of mixing was adjusted to 190 to 200°C.

[0048] Each sample obtained in the Examples and Comparative Examples was subjected to performance tests including penetration (25°C), softening point, viscosity (180°C), DS, degree of adhesion / peeling during a WT (Wheel Tracking) test, and the presence or absence of stringiness, as shown in Table 1. The test methods are described in detail below.

[0049]

[0050] The penetration (25°C) was measured according to JIS K 2207 "Petroleum asphalt - Penetration test method." This value is preferably 40 (0.1 mm) or more and 70 (0.1 mm) or less.

[0051] The softening point was measured according to JIS K2207 "Petroleum asphalt - softening point test method." This value is preferably 56 (°C) or higher.

[0052] The viscosity (180°C) was measured under the conditions of JPI-5S-54-99 "Asphalt - Viscosity test method using a rotational viscometer" at a measurement temperature of 180°C, using a spindle SC4-21, and a spindle rotation speed of 20 rpm.

[0053] This viscosity (at 180°C) is related to the hardness of the asphalt mixture during application, and if the viscosity becomes too high, application will become difficult and it will not be possible to create the desired pavement. Therefore, a viscosity of 800 mPa·s or less is preferable.

[0054] The strength of this asphalt binder composition is determined from DS based on the "B003 Wheel Tracking Test Method" described in the Pavement Survey and Testing Method Handbook (compiled by the Japan Road Association, a public interest incorporated association). DS is used exclusively as an index for measuring the strength of road pavements. However, when using binder compositions for waterproofing, adhesives, etc., similar improvements in strength may be required, and it is therefore entirely conceivable that this can be evaluated using DS. For this reason, while DS is used as an evaluation index, the present invention may be applied to any application, including not only road pavements but also waterproofing, adhesives, and the like.

[0055] The method for measuring DS will be explained below. DS is an index for evaluating the flow resistance (resistance to rutting) of a binder composition at high temperatures, and is measured using a wheel tracking tester. The wheel tracking test is carried out at 60°C, simulating a summer road surface. A test sample is prepared by mixing the binder composition with aggregate adjusted to a predetermined particle size as shown in Table 2 below, and is cured at 60°C for at least 5 hours, after which a wheel is driven over the sample for 1 hour. In the examples and comparative examples, a test sample 5 measuring 30 x 30 x 5 cm was cured, as shown in Figure 1.

[0056]

[0057] Next, this test piece 5 is made to travel back and forth at a pace of 42 times per minute in the direction of the arrow in the figure while a downward load of 686 N is applied by the wheels 11. Incidentally, the travel position of this wheel 11 is kept constant on the same travel path.

[0058] 2 shows an example of the amount of subsidence (mm) versus test time (minutes) when the start time of the DS measurement test is taken as the starting point. As the test time increases from the start time of the test, the amount of subsidence due to the reciprocating movement of the wheel 11 increases. This amount of subsidence is the depth (mm) of subsidence from the surface of the test specimen 5 in the depth direction.

[0059] When measuring DS, the amount of settlement from the start of the first test until 45 minutes has elapsed is not taken into consideration. This is because the amount of settlement is determined by factors such as the engagement with the added aggregate during the period from the start of the first test until 45 minutes has elapsed, making it impossible to evaluate the flow resistance in the true sense of the word.

[0060] When measuring DS, the focus is on the deformation d (mm) of the asphalt binder mixture over a 15-minute period, from 45 minutes to 60 minutes after the test start time. This d can be calculated by determining the difference between the settlement at 60 minutes after the test start time and the settlement at 45 minutes after the test start time. DS can be calculated using the following formula (2):

[0061] DS (times / mm) = Number of tire runs from 45 minutes to 60 minutes (times) / d (mm) (2) If the reciprocating frequency of the wheel 11 is 42 (times / min), equation (2) can be modified to the following equation (2)'.

[0062] DS (times / mm) = 630 (times) / d (mm) (2)'

[0063] The numerator in formula (2)' is 42 (cycles / min) x 15 (min) = 630 (cycles). In other words, this DS can be calculated from the number of tire runs per 15 minutes per d (mm). The higher this DS, the less deformation the binder mixture itself undergoes, making it a material that is resistant to rutting and has high strength.

[0064] DS is not measured using only the binder composition, but is measured using a specimen obtained by mixing aggregate (crushed stone, sand, stone powder (limestone), etc.) adjusted to the particle size shown in Table 2 with the binder composition under the specified conditions described below, just like in actual road pavement. In this example, the binder composition was mixed so that the content was 5.7% by weight based on the total amount of the asphalt pavement material (specimen).

[0065] The higher the DS, the stronger the asphalt, meaning that a paving material with high resistance to rutting can be provided. In the present invention, the desirable DS is set to 1000 times / mm or more.

[0066] A specific method for preparing a specimen for measuring DS using the binder composition of the present invention will be described below.

[0067] Crushed hard sandstone is used as aggregate, and crushed sand obtained by crushing hard sandstone, sea sand, and stone powder made from crushed limestone are used to prepare the fine particles (components with small particle diameters) used to prepare the test specimens.

[0068] The stone powder made from crushed limestone used to adjust the particle size of the aggregate conforms to JIS A 5008 "Limestone powder for paving" and has a passing mass percentage of 100% for a sieve opening of 600 μm, 90% to 100% for a sieve opening of 150 μm, and 70% to 100% for a sieve opening of 75 μm, and a moisture content of 1% or less.

[0069] The aggregate other than stone powder is crushed stone made of hard sandstone, and the aggregate satisfies the properties shown in (1) to (6) below.

[0070] (1) Water absorption rate of less than 1.5%, preferably less than 1.0% (JIS A1110). Here, crushed stone with a water absorption rate of 0.64% is used. If the aggregate has a high water absorption rate, the aggregate will absorb the coated asphalt binder, resulting in a mixture with a low amount of asphalt binder. Furthermore, aggregate with a high water absorption rate will absorb significantly depending on the humidity and surface wetness at the time of use, resulting in fluctuations in the amount of asphalt binder in the mixture. Therefore, in order to maintain a constant amount of asphalt binder in the mixture, the water absorption rate must be less than 1.5%, preferably less than 1.0%.

[0071] (2) Apparent density 2.60g / cm 3 Above, 2.70g / cm 3 Below (JIS A1110) Here, the apparent density is 2.66 g / cm 3 Crushed stone was used.

[0072] (3) Stability of 6% or less, preferably 3% or less (JIS A1122) Here, crushed stone with a stability of 2.4% was used. Stability here refers to stability against freezing and thawing. The smaller the stability value, the less aggregate destruction occurs during freezing and thawing. The pavement design and construction guidelines specify a stability of 12% or less, but in order to suppress variations in aggregate properties, we set it at half of the specified value.

[0073] (4) Abrasion loss of 20% or less, preferably 15% or less (JIS A1121) Here, crushed stone with an abrasion loss of 12.6% was used. The abrasion loss test is a test to evaluate the hardness of aggregate and its resistance to abrasion, i.e., the durability of aggregate. If the abrasion loss exceeds 20%, rutting will become severe, so here the abrasion loss was set to 20% or less, preferably 15% or less.

[0074] (5) Soft stone content: 5.0% or less, preferably 3.0% or less (JIS A1126) Here, crushed stone with a soft stone content of 2.5% was used. The soft stone content is determined by a test to see if a scratch can be made with a brass rod (Mohs hardness 3-4), and is a test to determine whether the aggregate is harder or softer than brass. Like the abrasion loss test, the soft stone content is a test to evaluate the hardness and resistance to abrasion of the aggregate, that is, the durability of the aggregate. The soft stone content generally needs to be 5% or less. (See Pavement Survey and Testing Methods Handbook A008.)

[0075] (6) The content of elongated or flat stone chips is 10.0% or less, preferably 5.0% or less (Pavement Design and Construction Guidelines (Regulatory Values) and Pavement Survey and Testing Methods Handbook A008 (Test Methods)). Here, crushed stone with a content of elongated or flat stone chips of 2.8% was used. The stone chips referred to here generally have a long axis / short axis ratio of 3 or more and are considered elongated or flat. If elongated or flat stone chips are mixed in, the pavement or test specimen may be more susceptible to deformation when subjected to a load from a certain direction. In other words, if a large number of elongated or flat stone chips are mixed in, they will be oriented in the same direction, and will be more susceptible to deformation when subjected to a load parallel to that direction than when subjected to a load perpendicular to that direction.

[0076] Therefore, when measuring rutting resistance (DS), unless the amount of elongated or flat stone chips mixed in is limited, the obtained value will vary greatly.

[0077] Crushed stone and stone powder satisfying these properties were used as aggregates, and the aggregate mix shown in Table 2 was adjusted to prepare test specimens under the conditions shown in Table 3.

[0078] The actual preparation of the specimens can be broadly classified into two steps: mixing the binder composition with the aggregate, and rolling. For the mixing, 608 g of the binder composition heated to 175°C and 10,065 g of aggregate heated to 175°C and compounded to the above-mentioned particle size (hereinafter, this adjusted particle size will be referred to as the compound particle size) are prepared.

[0079] First, the aggregate was placed in the mixer and mixed for 60 seconds to make it uniform. Mixing was stopped temporarily, and 608 g of the binder composition was added to the mixer. The binder composition and the aggregate were then mixed for 120 seconds.

[0080] After mixing, the binder composition and aggregate were placed in a frame for wheel tracking testing (inner dimensions: length 30.0 cm, width 30.0 cm, depth 5.0 cm) and roll-compacted.

[0081] Regarding the rolling compaction, a cylindrical roller with a radius of 460 mm is rolled over the mixed binder at the rolling temperature shown in Table 3 below, to apply rolling pressure to the binder. This rolling compaction is carried out in two stages, a primary rolling compaction and a secondary rolling compaction, and then the mixture is dried for 8 hours.

[0082]

[0083] The following explains the method for measuring the degree of adhesion and delamination during the WT test. Because light-colored binders have a higher affinity for rubber tires than typical black asphalt, a mixture containing the light-colored binder and aggregate adheres to the tires, easily causing the pavement adhered to the tires to peel off as the vehicle moves. To evaluate the performance of the pavement against this phenomenon, the extent to which the asphalt binder had peeled off from the pavement surface in the rutted areas where the tires had driven during the WT test was evaluated for test specimens that had undergone the WT test for DS measurement. The specific evaluation method is described below. Focusing on the rutted areas of the test specimens after the WT test, the state of binder peeling on the surface was traced on graph paper. The percentage (%) of the surface where binder had peeled off relative to the total area of ​​the rut was then estimated from the area of ​​the graph paper. If it was difficult to determine whether peeling had occurred, the pavement surface was illuminated with a light in a dark place and judged based on the light reflection. If the degree of adhesion / detachment is high, the surface of the pavement will be scraped and its flatness will be lost, so it is desirable that the degree of adhesion / detachment be 50% or less.

[0084] Since there are no specific regulations for testing for the occurrence of stringing in JIS or other standards, work gloves were worn on both hands, preferably double-layered, and samples of the asphalt binder compositions of the Examples and Comparative Examples obtained were heated to approximately 130°C, approximately 3 to 5 g were placed in the palm of the left or right hand, and the hands were placed together. The hands were then gradually moved apart by 5 cm or more, and the occurrence of stringing was confirmed by visual observation. If one or more strings were observed, the test was marked with an "X" indicating that stringing had occurred, and if no strings were observed, the test was marked with an "O" indicating that no stringing had occurred.

[0085] Examples and comparative examples will be described in detail below.

[0086] The petroleum-based solvent-extracted oil used in this study has the following typical properties: a kinematic viscosity of 512 mmHg at 60°C; 2 / s, flash point 338°C, aromatic content 65.9%.

[0087] The petroleum resin used in this verification has the following typical properties: a softening point of 140°C, an acid value specified in JIS K0070 of 0.1 mg KOH, a bromine value specified in JIS K2543 of 25 g, and a polyethylene-equivalent number average molecular weight of approximately 1,000 as measured by Gel Permeation Chromatography (GPC).

[0088] The SEBS used in this verification had a viscosity of 1800 mPa·s in a 10% toluene solution at 25° C. and a styrene content of 30%.

[0089] The MMA used in this verification had an MFR of 0.25 g / 10 min and an MMA blending ratio of 17 wt %.

[0090] The EEA used in this verification had an MFR of 0.5 g / 10 min and an EA blending ratio of 16 wt %.

[0091] The FT Wax 1 used in this test has a viscosity of 20 cP at 140°C, a freezing point of 99°C (measurement method D938), and a softening point of 110°C (measurement method ASTM D3954).

[0092] FT Wax 2 has a viscosity of 12.5 cP at 140°C and a melting point (JIS K2235.5.3.1)

[0093] The viscosity measurement method is based on JPI-5S-54-99 (Asphalt - Viscosity test method using a rotational viscometer).

[0094] The paraffin wax used had a melting point of 82°C ± 2°C.

[0095] The anti-stripping agent used in this verification was dimer acid (tall oil fatty acid dimer with 36 carbon atoms and an acid value of 190 to 210) to provide anti-stripping properties and compatibility with the aggregate.

[0096] The content ratios of the components in Examples 1 to 7 were all within the ranges specified in the present invention. All of Examples 1 to 7 met the criteria for the above-mentioned evaluation items. That is, the light-colored binder compositions of Examples 1 to 7 all had a penetration (25°C) of 40 (0.1 mm) to 70 (0.1 mm), a softening point of 56°C or higher, a viscosity (180°C) of 800 mPa·s or lower, a DS of 1000 times / mm or higher, an adhesion / detachment ratio of 50% or lower, and no stringiness was observed, earning them a rating of "Good." Therefore, it can be seen that by keeping the components within the ranges specified in the present invention, weather resistance, application ease, and durability can be improved while also suppressing adhesion / detachment to tires.

[0097] 5 Specimen 11 Wheel

Claims

1. A bright color binder composition comprising: a petroleum-based solvent-extracted oil; a petroleum resin; a thermoplastic elastomer: 1.6% by weight or more and 2.8% by weight or less; an ethylene copolymer: 3.5% by weight or more and 6.0% by weight or less; and an FT wax: 0.4% by weight or more and 0.99% by weight or less.

2. The bright color binder composition according to claim 1, wherein the thermoplastic elastomer is SEBS having a styrene content of 25.0% or more and 35.0% or less, and the ethylene copolymer is one or both of a methacrylate copolymer and an acrylate copolymer.

3. The light color binder composition of claim 2, wherein said methacrylate copolymer is ethylene methyl methacrylate (EMMA) and said acrylate copolymer is ethylene ethyl acrylate (EEA).

4. The bright color binder composition according to claim 3, wherein the methyl methacrylate (MMA) content of the EMMA is 10.0% or more and 20.0% or less, and the melt mass-flow rate (MFR) is 0.2 g / 10 min or more and 1.0 g / 10 min or less, and the EA content of the EEA is 10.0% or more and 20.0% or less, and the MFR is 0.2 g / 10 min or more and 1.0 g / 10 min or less.

5. The light color binder composition according to any one of claims 1 to 4, characterized in that the light color binder composition contains an anti-stripping agent.

6. The bright color binder composition according to claim 5, wherein the anti-stripping agent is a dimer acid, and the content thereof is 0.2% by weight or more and 2.0% by weight or less based on the total weight of the composition.

7. An asphalt pavement material comprising the light-colored binder composition according to any one of claims 1 to 6 and aggregate.

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