Classifications

• • E—FIXED CONSTRUCTIONS
  • E01—CONSTRUCTION OF ROADS, RAILWAYS, OR BRIDGES
  • E01C—CONSTRUCTION OF, OR SURFACES FOR, ROADS, SPORTS GROUNDS, OR THE LIKE; MACHINES OR AUXILIARY TOOLS FOR CONSTRUCTION OR REPAIR
  • E01C7/00—Coherent pavings made in situ
  • E01C7/08—Coherent pavings made in situ made of road-metal and binders
  • E01C7/18—Coherent pavings made in situ made of road-metal and binders of road-metal and bituminous binders
  • E01C7/26—Coherent pavings made in situ made of road-metal and binders of road-metal and bituminous binders mixed with other materials, e.g. cement, rubber, leather, fibre
  • E01C7/265—Coherent pavings made in situ made of road-metal and binders of road-metal and bituminous binders mixed with other materials, e.g. cement, rubber, leather, fibre with rubber or synthetic resin, e.g. with rubber aggregate, with synthetic resin binder
• • C—CHEMISTRY; METALLURGY
  • C08—ORGANIC MACROMOLECULAR COMPOUNDS; THEIR PREPARATION OR CHEMICAL WORKING-UP; COMPOSITIONS BASED THEREON
  • C08L—COMPOSITIONS OF MACROMOLECULAR COMPOUNDS
  • C08L25/00—Compositions of, homopolymers or copolymers of compounds having one or more unsaturated aliphatic radicals, each having only one carbon-to-carbon double bond, and at least one being terminated by an aromatic carbocyclic ring; Compositions of derivatives of such polymers
  • C08L25/02—Homopolymers or copolymers of hydrocarbons
  • C08L25/04—Homopolymers or copolymers of styrene
  • C08L25/08—Copolymers of styrene
• • C—CHEMISTRY; METALLURGY
  • C08—ORGANIC MACROMOLECULAR COMPOUNDS; THEIR PREPARATION OR CHEMICAL WORKING-UP; COMPOSITIONS BASED THEREON
  • C08L—COMPOSITIONS OF MACROMOLECULAR COMPOUNDS
  • C08L53/00—Compositions of block copolymers containing at least one sequence of a polymer obtained by reactions only involving carbon-to-carbon unsaturated bonds; Compositions of derivatives of such polymers
• • C—CHEMISTRY; METALLURGY
  • C08—ORGANIC MACROMOLECULAR COMPOUNDS; THEIR PREPARATION OR CHEMICAL WORKING-UP; COMPOSITIONS BASED THEREON
  • C08L—COMPOSITIONS OF MACROMOLECULAR COMPOUNDS
  • C08L95/00—Compositions of bituminous materials, e.g. asphalt, tar, pitch
• • C—CHEMISTRY; METALLURGY
  • C08—ORGANIC MACROMOLECULAR COMPOUNDS; THEIR PREPARATION OR CHEMICAL WORKING-UP; COMPOSITIONS BASED THEREON
  • C08L—COMPOSITIONS OF MACROMOLECULAR COMPOUNDS
  • C08L2555/00—Characteristics of bituminous mixtures
  • C08L2555/40—Mixtures based upon bitumen or asphalt containing functional additives
  • C08L2555/80—Macromolecular constituents
  • C08L2555/84—Polymers comprising styrene, e.g., polystyrene, styrene-diene copolymers or styrene-butadiene-styrene copolymers
• • C—CHEMISTRY; METALLURGY
  • C08—ORGANIC MACROMOLECULAR COMPOUNDS; THEIR PREPARATION OR CHEMICAL WORKING-UP; COMPOSITIONS BASED THEREON
  • C08L—COMPOSITIONS OF MACROMOLECULAR COMPOUNDS
  • C08L2666/00—Composition of polymers characterized by a further compound in the blend, being organic macromolecular compounds, natural resins, waxes or and bituminous materials, non-macromolecular organic substances, inorganic substances or characterized by their function in the composition
  • C08L2666/02—Organic macromolecular compounds, natural resins, waxes or and bituminous materials
  • C08L2666/24—Graft or block copolymers according to groups C08L51/00, C08L53/00 or C08L55/02; Derivatives thereof
• • C—CHEMISTRY; METALLURGY
  • C08—ORGANIC MACROMOLECULAR COMPOUNDS; THEIR PREPARATION OR CHEMICAL WORKING-UP; COMPOSITIONS BASED THEREON
  • C08L—COMPOSITIONS OF MACROMOLECULAR COMPOUNDS
  • C08L53/00—Compositions of block copolymers containing at least one sequence of a polymer obtained by reactions only involving carbon-to-carbon unsaturated bonds; Compositions of derivatives of such polymers
  • C08L53/02—Compositions of block copolymers containing at least one sequence of a polymer obtained by reactions only involving carbon-to-carbon unsaturated bonds; Compositions of derivatives of such polymers of vinyl-aromatic monomers and conjugated dienes

Definitions

• the present invention relates to a modified asphalt composition containing asymmetric styrene-butadiene-styrene triblock copolymer as modifier. More particularly, this invention relates to a modified asphalt composition containing asymmetric styrene-butadiene-styrene triblock copolymer showing an excellent balance of ductility at low temperatures and high flow resistance at high temperatures.
• a modified asphalt composition has been developed by addition of polymer to the asphalt.
• polymer for example, low density polyethylene, ethylenevinylacetate, styrene-butadiene rubber, buthyl rubber and/or mixture of them have been used for asphalt modifier to resist the permanent deformation at high temperature as well as to resist impact crack caused by repeated weight pressure and tensile strength at low temperature.
• modified asphalt has been increasing in the field of industry.
• asphalt modifier a radial type of styrene-butadiene block copolymer has been also suggested as asphalt modifier, because it enhances the processibility, softening point, stability and/or viscosity of asphalt composition.
• asphalt composition can be used as looping, coating, hot-melt, asphalt concrete and/or silant composition.
• modified asphalt composition shows excellent physical properties, such as, good thermal resistance, anti-aging property and resistance against permanent deformation.
• Such enhancement of physical properties in modified asphalt composition results from the increase of liquidity resistance caused by high viscosity at high temperature, the increase of impact resistance at low temperature and the increase of anti-aging property from light or air, because the polymers in asphalt composition enhances the matrix of asphalt by forming polymer domain.
• the anti-crack property at low temperature depends on the ductility of asphalt composition. If the ductility of asphalt composition increases, the liquidity of modified asphalt composition is enhanced at low temperature. Of course, the crack of asphalt caused by pressure fatigue or thermal deformation is also declined if the ductility of asphalt composition increases. Therefore, ductility is very important factor for estimating the crack resistance at low temperature.
• asphalt polymer modifier has a role for enhancing liquidity and declining the thermal sensitivity in low temperature as well as for resisting the deformation in high temperature. Further, it has a role for improving physical properties, such as, tensile strength, stiffness, tenesity, adhesion with aggregate.
• the improvement of stability in low temperature depends on the kinds of polymers inserted as modifier. Even though the structure of polymer is similar, the resistance against thermal sensitivity can be varied.
• polyolefin, styrene-butadiene random copolymer rubber and/or styrene-butadiene block copolymer rubber can be used as polymer asphalt modifier.
• styrene-butadiene random copolymer rubber or styrene-butadiene block copolymer rubber has a role for enhancing ductility, which prevents the crack caused by repeated tensile force at low temperature.
• the inventors of present invention have researched an enhanced asphalt modifier showing excellent ductility at low temperature, while the physical properties in high temperature have been still maintained.
• asymmetric styrene-butadiene-styrene block copolymer enhances the ductility and thermal stability of asphalt composition at low temperature, which has not been anticipated from conventional asphalt modifier, such as, linear or radial styrene-butadiene block copolymer rubber.
• the object of the present invention is to provide a modified asphalt composition containing asymmetric styrene-butadiene-styrene triblock copolymer as modifier showing excellent ductility and thermal stability at low temperature and the resistance to permanent deformation at high temperature.
• the object of the present invention is to provide a modified asphalt composition
• a modified asphalt composition comprising i) 100 wt. part of natural asphalt; and ii) 0.5 ⁇ 40 wt. part of asymmetric triblock copolymer having number average molecular weight of 20,000 ⁇ 1,000,000 represented as following formula 1.
• A-B-A′ (formula 1)
• A represents a vinyl aromatic polymer block having number average molecular weight of 8,000 ⁇ 30,000;
• B represents a conjugated-diene polymer block or a conjugated-diene copolymer block having a small amount of vinyl aromatic monomers
• A′ represents a vinyl aromatic polymer block having number average molecular weight of 500 ⁇ 5,000;
• weight amount of A and A′ block is 5 ⁇ 40 wt % of total A-B-A′ triblock copolymer, and the percentage of vinyl aromatic monomer in the block A+A′ as to total vinyl aromatic monomer amount in A-B-A′ is 50 ⁇ 98%.
• said vinyl aromatic polymer block (A or A′) comprises monomers at least one selected from the group consisting of styrene, a-methylstyrene, o-methylstyrene, p-methylstyrene and p-tert-butylstyrene, and said vinyl aromatic monomer is preferably a styrene.
• said conjugated-diene polymer block (B) is a homopolymer block consisting of butadiene or a tapered block consisting of most of butadienes and a small amount of conjugated diene monomers.
• the number average molecular weight of said compound of formula 1 is 50,000 ⁇ 400,000.
• the asphalt composition preferably comprises i) 100 wt. part of natural asphalt and ii) 1 ⁇ 20 wt. part of asymmetric triblock copolymer represented by formula 1.
• the present invention also provide a modified asphalt composition further comprising linear or radial block copolymer as to the modified asphalt composition described above.
• the present invention also provide a usage of said modified asphalt composition as to pavement of road or manufacturing water proof sheet.
• the asphalt modifier of the present invention can be an asymmetric styrene-butadiene-styrene block copolymer represented by formula 1.
• the number average molecular weight of asymmetric styrene-butadiene-styrene block copolymer represented by formula 1 is 20,000 ⁇ 1,000,000, preferably 50,000 ⁇ 400,000.
• the number average molecular weight of said block copolymer is less than 20,000, the mechanical properties of copolymer can not be fully expressed. On the other hand, if the number average molecular weight is more than 1,000,000, the processibility of copolymer can be declined.
• Said vinyl aromatic polymer block (A or A′) comprises monomers at least one selected from the group consisting of styrene, a-methylstyrene, o-methylstyrene, p-methylstyrene and p-tert-butylstyrene, and said vinyl aromatic monomer is preferably a styrene.
• the weight amount of A and A′ block is 5 ⁇ 40 wt % of total A-B-A′ triblock copolymer, and the percentage of vinyl aromatic monomer in the blocks A+A′ as to total vinyl aromatic monomer amount in A-B-A′ is 50 ⁇ 98%.
• the difference of number average moleculae weight between block A and block A′ can be 3,000 ⁇ 29,500, which shows that block A and block A′ are asymmetric blocks.
• Said conjugated-diene polymer block (B) is a homopolymer block consisting of butadiene or a tapered block consisting of most amount of butadienes and a small amount of conjugated diene monomers.
• Said asymmetric styrene-butadiene-styrene triblock copolymer represented by formula 1 can be prepared by conventional continuous polymerization method in the presence of anion initiator, such as, organic lithium compound.
• the asphalt composition of the present invention comprises i) 100 wt. part of natural asphalt and ii) 0.5 ⁇ 40 wt. part of asymmetric triblock copolymer represented by formula 1, preferably, 1 ⁇ 25 wt. part of asymmetric triblock copolymer represented by formula 1. If the amount of asymmetric triblock copolymer represented by formula 1 is less than 0.5 wt. part, this triblock copolymer cannot make a role as asphalt modifier, because it cannot fully express the function of polymer. On the other hand, if the amount of asymmetric triblock copolymer represented by formula 1 is more than 40 wt.
• this triblock copolymer can result in extremely high viscosity, which causes the decline of dispersion between asphalt and modifier as well as the decline of liquidity by the delay of dispersion. Further, in this case, the mechanical cracking or thermal decomposition of binder can be occur.
• the amount of sulfur in modified asphalt composition can be 0.1 ⁇ 20 wt. part as to 100 wt. part of styrene-butadiene-styrene block copolymer, preferably, 1 ⁇ 10 wt. part.
• styrene-butadiene-styrene triblock copolymer represented by formula 1 has asymmetric styrene blocks. Of course, it has excellent ductility in low temperature, which results in excellent ductility and thermal stability at low temperature and the resistance to permanent deformation at high temperature.
• the analysis of molecular weight is measured by high performance liquid chromatography ‘separation's module Waters 2690’ as well as by detector ‘differential refractometer Waters 410’. Following are analysis conditions. The temperature of column is 41° C., solvent is THF and flow rate is 0.3 mL/min. Column is used by linear connection of divinylbenzene Styragel HR 5E, HR 4, HR 2. The standard of polystyrene is employed to measure the difference of refraction rate by the refraction detector.
• the amount of styrene and butadiene as well as the micro structure of polymer are measured by Bruker NMR-200 and NMR400.
• the testing materials are prepared using chloroform-d solvent.
• copolymer solution viscosity is carried out using polymer solution dissolved with toluene in a concentration of 5.23 wt %. At 25° C. constant temperature, the visicosity is measured by Ubbelohde visicosity meter under the condition that constant K is 0.09048 mm 2 /s 2 . TABLE 1 Styrene Percentage Molecular Solution Amount of Block(%) Weight(Mn) Viscosity(cps) Pre. Ex. 1 14.8 92 192,000 21 Pre. Ex. 2 14.5 83 201,000 21 Pre. Ex. 3 15.2 88 190,000 20 Pre. Ex. 4 14.8 78 195,000 21 Pre. Ex. 5 22.3 93 202,000 18 Com. Pre. 14.8 91 198,000 21 Ex. 1 Com. Pre. 29.8 97 195,000 12 Ex. 2 Com. Pre. 30.1 96 209,000 21 Ex. 3
• the testing materials are prepared according to the process comprising the steps of i) heating the modified asphalt composition, ii) pouring the melting composition to the mold, and iii) cooling the composition (KS M 2254).
• measurement protocol comprising the steps of i) inserting the testing materials into 5° C. water bath, ii) forcing tensile strength at both ends in a velocity of 3 cm/min, and iii) measuring the length when the testing materials are divided are employed.
• Table 2 shows the softening point and ductility length of testing materials.
• the testing materials are prepared according to the process comprising the steps of i) heating the modified asphalt composition, ii) pouring the melting composition to the mold, and iii) cooling the composition (KS M 2254).
• measurement protocol comprising the steps of i) inserting the testing materials into 5° C. water bath, ii) forcing tensile strength at both ends in a velocity of 3 cm/min, and iii) measuring the length when the testing materials are divided are employed.
• Table 2 shows the softening point and ductility length of testing materials.
• TABLE 2 Amount of Ductility block Before After copolymer Softening RTFO(rolling RTFO(rolling modifier point thin film oven) thin film oven) (wt. part) (° C.) (5° C., cm) (5° C., cm) Ex. 1 3.5 74 39.5 24.5 Ex. 2 3.5 77 36.1 26.1 Ex. 3 3.5 79 36.4 26.1 Ex. 4 3.5 92 40.5 26.5 Ex. 5 3.5 94 33.8 24.9 Com.
• an asphalt compositions comprising asymmetric styrene-butadiene-styrene block copolymer prepared in Example 4 and 5 show higher softening point compared to Example 1, which means that the resistance against permanent deformation has been maintained at high temperature.
• the softening points of compositions prepared in Example 4 and 5 are similar to that of Comparative Example 2 having high styrene amount.
• the compositions prepared in Example 4 and 5 show that the ductility after rolling thin film oven has been remarkably enhanced. Of course, it means that the ductility of at low temperature is also enhanced, while the crack caused by fatigue or thermal deformation is declined. Therefore, the asphalt composition prepared in Examples can be regarded as suitable asphalt composition for pavement of road.
• comparing radial type polymer in Comparative Example 3 the asphalt compositions prepared in Examples show the better ductility, while softening points are not better than that of radial type polymer.

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• Chemical & Material Sciences (AREA)
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• Structural Engineering (AREA)
• Engineering & Computer Science (AREA)
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• Medicinal Chemistry (AREA)
• Polymers & Plastics (AREA)
• Organic Chemistry (AREA)
• Architecture (AREA)
• Materials Engineering (AREA)
• Compositions Of Macromolecular Compounds (AREA)
• Graft Or Block Polymers (AREA)

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• 2005
  • 2005-04-20 KR KR1020050032650A patent/KR100639893B1/ko active IP Right Grant
  • 2005-08-30 US US11/213,892 patent/US20060241218A1/en not_active Abandoned
  • 2005-09-28 CN CNB2005101054902A patent/CN100549099C/zh not_active Expired - Fee Related

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