WO2015127561A1

WO2015127561A1 - Polymer modified asphalt compositions utilizing an ionomeric elastomer and methods of preparation for crack and joint sealers

Info

Publication number: WO2015127561A1
Application number: PCT/CA2015/050149
Authority: WO
Inventors: Dana Adkinson
Original assignee: Lanxess Inc.
Priority date: 2014-02-27
Filing date: 2015-02-27
Publication date: 2015-09-03

Abstract

A polymer modified asphalt composition has asphalt, an oil, a polymer additive and an ionomer. The composition may be used in a sealant to seal a crack or joint in a concrete or asphalt structure. The sealant is applied to the crack or joint in an amount sufficient to fill the crack or joint and the sealant is cured to cause bonding of the sealant to the crack or joint. The composition may be prepared by heating a mixture of asphalt, an oil, a polymer additive, an aggregate and an ionomer, and blending the mixture for a time sufficient to homogeneously mix the ingredients.

Description

Polymer Modified Asphalt Compositions Utilizing An lonomeric Elastomer And Methods Of Preparation for Crack and Joint Sealers

Field

This invention relates to a polymer modified asphalt composition containing an asphalt, a polymer additive, oil and an ionomer prepared by reacting a halogenated butyl polymer with at least one nitrogen and/or phosphorus based nucleophile.

BACKGROUND OF THE INVENTION

Open cracks and joints in concrete or asphaltic concrete pavements present a path for intrusion of water into the base and sub-base of the highway. Water intrusion beneath the pavement causes erosion of the foundation and accumulated water can cause the pavement to break up due to alternate freezing and thawing cycles. Water intrusion ultimately contributes to the failure of the pavement structure.

In the maintenance of concrete or asphaltic roads, sidewalks, highways, driveways and the like, various types of crack and joint fillers or sealants have been employed to connect adjacent segments of the surface structure or to repair cracks or small holes. Such sealants must exhibit several properties to be satisfactory. The sealant must adhere well to the substrate and must maintain its strength and adhesive properties over a wide range of temperatures and in dry, wet and icy conditions. In addition, the sealant must be capable of withstanding movements of the substrate surface to which it is adhered which may result from deformation when a load is placed on the surface or from surface movement during temperature changes.

The most commonly used sealants are asphalt-based sealants, such as rubberized asphalt. Such sealants are often poor in adhesion to surfaces such as concrete or asphalt. In concrete highways, joints sealed with asphalt-based sealants commonly fail within 3 to 6 months. When the concrete or asphalt substrate moves slightly, the adhesive bond to the substrate is often ruptured. In addition, due to the inherent composition of asphalts, certain physical properties can vary widely with changes in temperature. Plastic deformation may occur easily due to temperature or load, leading to crack formation. In the evaluation of crack resistance, ductility is an important consideration. High ductility results in increased flexibility of asphalt particularly at low temperature, thereby significantly reducing fatigue caused by loads or crack due to thermal expansion and contraction. Accordingly, ductility can be considered as an important factor in evaluating crack resistance caused by loads particularly in cold regions

Resistance to plastic deformation, temperature sensitivity, fatigue crack, cold crack, etc. may be deteriorated significantly as time goes by and depending on traffic volume. For this reason, polymers are often added to asphalt to extend the range of physical properties. Several polymers have been identified that are effective modifiers for use in polymer modified asphalt sealants, such as low density polyethylene, ethylene vinyl acetate, styrene-butadiene rubber, butyl rubber. Different polymers give different effects, however, on the physical and rheological properties depending on the structure of the polymer.

U.S. Patent No. 3,985,694 and U.S. Patent No. 4, 130,516 disclose an asphalt/polymer composition with improved properties comprising asphalt and a thermoplastic elastomer such as linear polyethylene, ethylene vinyl acetate or styrene-butadiene rubber.

U.S. Patent No. 3,345,316 discloses an asphalt composition prepared by adding 10 to 30 parts by weight of a thermoplastic elastomer such as a linear styrene-butadiene-styrene triblock copolymer or a styrene-ethylene-butylene- styrene block copolymer obtained by anionic polymerization to a chlorinated polyphenylene resin, without the necessity for a vulcanizing treatment or vulcanizing agent.

U.S. Patent No. 4, 130,516 discloses an asphalt composition comprising asphalt, sulfur and a polymer. The polymer is included in an amount of 1 weight % and may be either natural rubber or synthetic rubber. But, whereas the addition of a radial styrene-butadiene random copolymer does not provide improved ductility, a linear styrene-butadiene random copolymer results in improved ductility.

In general, polymer modified asphalt sealants have improved flexibility and reduced temperature sensitivity at low temperature, and improved flow resistance and restricted deformation at high temperature. In addition, it has improved tensile strength, stiffness, tenacity, adhesion to aggregate and, thus, prevents the breakage of paving caused by the flow of aggregate.

The improvement of the properties of an asphalt composition by the addition of a polymer is largely affected by the properties of the added polymer. Therefore, it desired to provide an polymer modified asphalt sealant with improved properties.

SUMMARY

According to an aspect of the invention, there is provided a polymer modified asphalt composition, comprising: asphalt; an oil, a polymer additive; and an ionomer.

According to another aspect of the invention, there is provided a method to seal a crack or joint in a concrete or asphalt structure comprising: applying a sealant to the crack or joint, said sealant comprising an asphalt, an oil, a polymer additive, and an ionomer, said sealant applied in an amount sufficient to fill said crack or joint; and, curing said sealant under suitable conditions to cause bonding of the sealant to the crack or joint.

According to yet another aspect of the invention, there is provided a method to prepare a hot mix asphalt composition comprising the steps of: heating ingredients comprising an asphalt, an oil, a polymer additive an aggregate and an ionomer; and, blending for a time sufficient to homogeneously mix the ingredients. DETAILED DESCRIPTION

The present invention relates to polymer modified asphalt compositions comprising asphalt, a polymeric additive, oil and an ionomeric copolymer, and the process of making such asphalt compositions.

Asphalt is a bituminous material which is produced during the distillation of crude oil. Typically, asphalt is derived from the high molecular weight bottoms of vacuum distillation towers and has an atmospheric equivalent boiling point of at least 350 °C. Due to the hydrophobic nature of the asphalt the material and its good adhesive properties and weathering characteristics, asphalt can be used as an adhesive (in particular in the construction industry) or as a binder component of road paving materials. In general, the asphalt can be mixed with aggregate material such as rock, sand, gravel, crushed stone, etc. for use in paved surfaces. As used herein, the term "asphalt" may also be referred to as "bitumen" in either natural or manufactured forms.

A wide variety of asphalts may be used in accordance with certain embodiments of the present invention. The asphalt used in the present invention may be obtained from a variety of sources, for example, but not limited to, straight-run vacuum residue; mixtures of vacuum residue with diluents such as vacuum tower wash oil, paraffin distillate, aromatic and naphthenic oils, and mixtures thereof; oxidized vacuum residues or oxidized mixtures of vacuum residues and diluent oils; and the like. Other asphaltic materials such as coal tar pitch, rock asphalt, and naturally occurring asphalt may also be used, as part or whole of the asphalt composition. The asphalt may also conform to specification of viscosity graded and/or penetration graded bitumens. In an embodiment, the asphalt will typically comprise about 30 to about 99% by weight of the final asphalt-polymer composition, or any amount therebetween.

Polymer additives which are traditionally added to asphalt to produce a modified asphalt meeting performance-grade standards may include but are not limited to natural rubbers, synthetic rubbers, plastomers, thermoplastic resins, thermosetting resins, elastomers, and combinations thereof. Examples of these modifiers include styrene-butadiene-styrene (SBS), styrene-butadiene rubber (SBR), styrene-butadiene (SB), styrene-isoprene-styrene(SIS), styrene-isoprene- butadiene-styrene (SIBS), poly-isoprene, polybutylenes, butadiene-styrene rubbers, vinyl polymers, ethylene vinyl acetate, ethylene vinyl acetate derivatives, atactic polypropylene (APP), isotactic polypropylene, ethylene-propylene copolymer, thermoplastic polyolefin (TPO), amorphous poly alpha olefin (APAO) or polyethylene (PE), ethyl vinyl acetate (EVA) and the like. The styrene- butadiene copolymers are copolymers that may or may not be hydrogenated (preferably are non-hydrogenated), such as styrene-butadiene, diblock ("SB") and styrene-butadiene-styrene linear and radial triblock ("SBS") polymer (hereinafter collectively and severally "styrene-butadiene"). Various other polymers such as EPDM refers to terpolymers containing ethylene and propylene units in the polymer backbone and a diene-containing monomer with the diene moiety usually in the pendant position to the chain backbone; the term "EPDM" is further defined as ASTM D-1418-64. These polymers may be incorporated as the primary polymer or as a mixture of one or more polymers. Asphalt modified compositions may additionally contain recycled crumb rubber (either coarse of fine grain) from recycled tires or ground plastics. In an embodiment, the polymer additive can be present in the modified asphalt composition in an amount from about 0.5-30%, preferably 0.5-25% and more preferably 1 -20% by weight of the final asphalt- polymer composition.

Additionally, other polymeric materials that may be suitable for use as binders are not particularly limited and include: curable resins such as epoxy resin/hardener systems, acrylic latex, vinyl, neoprene latex, water based epoxy, water based polyurethane, fluorocarbons, modified phenylene oxides, nylons, polyethylene terephthalate, polybutylene, terephthalate, phenolics, polyamides, polycarbonates, polyetheretherketones, polyaryletherketones, polyether imides, polyphenylene sulfides, polysulfones, polyarylsulfones, styrene, polyester copolymers, styrenics, such as, polystyreneacrylonitrile-butadiene-styrene, styrene-acrylonitrile, styrene-butadiene, and styrene-maleic anhydride copolymers and the like. For the purposes of the subject matter disclosed herein, the terms "halobutyl rubber", "halobutyl polymer" and "halogenated isoolefin copolymer" may be used interchangeably. The halogenated copolymers used in the present invention are copolymers of at least one isoolefin monomer and one or more multiolefin monomers and optionally one or more alkyl substituted aromatic vinyl monomers.

Isoolefins having from 4 to 7 carbon atoms are suitable for use in the present invention. Specific examples of such C₄ to C₇ isomonoolefins include isobutylene, 2-methyl-1 -butene, 3-methyl-1 -butene, 2-methyl-2-butene, 4-methyl- 1 -pentene and mixtures thereof. The preferred C₄ to C₇ isomonoolefin monomer is isobutylene.

Suitable Multiolefin monomers copolymerizable with the isoolefin monomers may include dienes, for example conjugated dienes. Particular examples of multiolefin monomers include those having in the range of from 4-14 carbon atoms. Examples of suitable multiolefin monomers include isoprene, butadiene, 2-methylbutadiene, 2,4-dimethylbutadiene, piperyline, 3-methyl-1 ,3- pentadiene, 2,4-hexadiene, 2-neopentylbutadiene, 2-methyl-1 ,5-hexadiene, 2,5- dimethyl-2,4-hexadiene, 2-methyl-1 ,4-pentadiene, 4-butyl-1 ,3-pentadiene, 2,3- dimethyl-1 ,3-pentadiene, 2,3-dibutyl-1 ,3-pentadiene, 2-ethyl-1 ,3-pentadiene, 2- ethyl-1 ,3-butadiene, 2-methyl-1 ,6-heptadiene, cyclopentadiene, methylcyclopentadiene, cyclohexadiene, 1 -vinyl-cyclohexadiene and mixtures thereof. A particularly preferred conjugated diene is isoprene. β-pinene may also be used instead of or in addition to the multiolefin monomer. Herein multiolefin/β- pinene monomers refers to the presence or use of one or more multiolefin monomers and/or β-pinene monomer.

The butyl polymer may optionally include one or more additional copolymerizable monomers along with the isoolefin and multiolefin/ -pinene monomers. Additional copolymerizable monomers include monomers copolymerizable with the isoolefin and/or multiolefin/ -pinene monomers. Suitable copolymerizable monomers include, for example, styrenic monomers, such as alkyl-substituted vinyl aromatic co-monomers, including but not limited to a C C₄ alkyl substituted styrene. Specific examples of copolymerizable monomers include, for example, a-methyl styrene, p-methyl styrene, chlorostyrene, cyclopentadiene and methylcyclopentadiene. In one embodiment, the butyl rubber polymer may comprise random copolymers of isobutylene, isoprene and p- methyl stryene.

The butyl polymers are formed from a mixture of monomers described herein. In one embodiment, the monomer mixture comprises from about 80% to about 99% by weight of an isoolefin monomer and from about 1 % to 20% by weight of a multiolefin/ -pinene monomer. In another embodiment, the monomer mixture comprises from about 85% to about 99% by weight of an isoolefin monomer and from about 1 % to 15% by weight of a multiolefin/ -pinene monomer. In certain embodiments, three monomers may be employed. In these embodiments, the monomer mixture may comprise about 80% to about 99% by weight of isoolefin monomer, from about 0.5% to about 5% by weight of a multiolefin/ -pinene monomer, and from about 0.5% to about 15% by weight a third monomer copolymerizable with the isoolefin and/or multiolefin/ -pinene monomers. In one embodiment, the monomer mixture comprises from about 68% to about 99% by weight of an isoolefin monomer, from about 0.5% to about 7% by weight of a multiolefin/ -pinene monomer and from about 0.5% to about 25% by weight of a third monomer copolymerizable with the isoolefin and/or multiolefin/β- pinene monomers.

The butyl polymer may be prepared by any suitable method, of which several are known in the art. For example, the polymerization of monomers may be performed in the presence of AICI₃ and a proton source and/or cationogen capable of initiating the polymerization process. A proton source includes any compound that will produce a proton when added to AICI₃ or a composition containing AICI₃. Protons may be generated from the reaction of AICI₃ with proton sources such as water, alcohol or phenol to produce the proton and the corresponding by-product. Such reaction may be preferred in the event that the reaction of the proton source is faster with the protonated additive as compared with its reaction with the monomers. Other proton generating reactants include thiols, carboxylic acids, and the like. The most preferred proton source is water. The preferred ratio of AICI₃ to water is from 5:1 to 100:1 by weight. It may be advantageous to further introduce AICI₃ derivable catalyst systems, diethylaluminium chloride, ethylaluminium chloride, titanium tetrachloride, stannous tetrachloride, boron trifluoride, boron trichloride, or methylalumoxane. Inert solvents or diluents known to the person skilled in the art for butyl polymerization may be considered as the solvents or diluents (reaction medium). These include alkanes, chloroalkanes, cycloalkanes or aromatics, which are frequently also mono- or polysubstituted with halogens. Hexane/chloroalkane mixtures, methyl chloride, dichloromethane or the mixtures thereof may be preferred. Chloroalkanes are preferably used. The monomers are generally polymerized cationically, preferably at temperatures in the range from -120^ to +20^, preferably in the range from -l OO'C to -20°C, and pressures in the range from 0.1 to 4 bar.

The butyl polymer may also be produced via a solution process as outlined in WO201 1089083 A1 and references therein. A C₆ solvent is a particularly preferred choice for use in a solution process. C₆ solvents suitable for use in the present invention preferably have a boiling point of between 50 °C and 69 °C. Examples of preferred C₆ solvents include n-hexane or hexane isomers, such as 2-methyl pentane or 3-methyl pentane, or mixtures of n-hexane and such isomers as well as cyclohexane.

The butyl polymer may comprise at least 0.5 mol% repeating units derived from the multiolefin/ -pinene monomers. In some embodiments, the repeating units derived from the multiolefin/ -pinene monomers may be present in the butyl rubber polymer in an amount of at least 0.75 mol%, or at least 1 .0 mol%, or at least 1 .5 mol%, or at least 2.0 mol%, or at least 2.5 mol%, or at least 3.0 mol%, or at least 3.5 mol%, or at least 4.0 mol%, or at least 5.0 mol%, or at least 6.0 mol%, or at least 7.0 mol%. In one embodiment, the butyl rubber polymer may comprise from 0.5 to 2.2 mol% of the multiolefin/ -pinene monomers. In another embodiment, the butyl rubber polymer may comprise higher multiolefin/ -pinene monomer content, e.g. 3.0 mol% or greater. The preparation of suitable high multiolefin/ -pinene butyl rubber polymers is described in Canadian Patent Application 2,418,884, which is incorporated herein by reference. In one embodiment, the halogenated butyl rubber polymer may be obtained by first preparing a butyl rubber polymer from a monomer mixture comprising one or more isoolefins, and one or more multiolefins and/or β-pinene, followed by subjecting the resulting copolymer to a halogenation process to form the halogenated butyl rubber polymer. Halogenation can be performed according to the process known by those skilled in the art, for example, the procedures described in Rubber Technology, 3rd Ed., Edited by Maurice Morton, Kluwer Academic Publishers, pp. 297-300 and further documents cited therein. Halogenation may involve bromination and/or chlorination. Brominated butyl rubber polymers may be of particular note. For example, a brominated butyl rubber comprising isobutylene and less than 2.2 mole percent isoprene is commercially available from LANXESS Deutschland GmbH and sold under the name BB2030™.

In the halogenated butyl polymers one or more of the repeating units derived from the multiolefin monomers comprise an allylic halogen moiety. During halogenation, some or all of the multiolefin and/or β-pinene content of the copolymer is converted to units comprising allylic halides. These allylic halide sites in the halobutyl rubber polymer result in repeating units derived from the multiolefin monomers and/or β-pinene originally present in the butyl rubber polymer. The total allylic halide content of the halogenated butyl rubber polymer cannot exceed the starting multiolefin and/or β-pinene content of the parent butyl rubber polymer, however residual allylic halides and/or residual multiolefins may be present. The allylic halide sites allow for reacting with and attaching one or more nucleophiles to the halobutyl rubber polymer. The halogenated butyl rubber polymer may have a total allylic halide content from 0.05 to 2.0 mol%. The halogenated butyl rubber polymer may also contain residual multiolefin levels ranging from 2 to 10 mol %.

In an embodiment, the ionomers of the present invention may be obtained by reacting a halogenated butyl rubber polymer with a nucleophile having no pendant vinyl group, a nucleophile comprising a pendant vinyl group or a mixture thereof. The halogenated rubber polymer may be reacted first with a nucleophile having no pendant vinyl group and then with a nucleophile having a pendant vinyl group.

Nucleophiles suitable for the preparation of the butyl rubber ionomers may contain at least one neutral phosphorus or nitrogen center, which possess a lone pair of electrons, the lone pair being both electronically and sterically accessible for participation in nucleophilic substitution reactions. The butyl rubber ionomers obtained from such nucleophiles would comprise phosphorus-based or nitrogen- based ionic moieties.

In one embodiment, the allylic halide sites of the halogenated butyl rubber polymers are reacted with nucleophiles (with or without a pendant vinyl group) having of formula (I):

wherein,

A is a nitrogen or phosphorus; and,

R1 , R2 and R3 are independently: a vinyl group, a linear or branched C1 -C18 alkyl group; a linear or branched C1 -C1 8 alkyl group comprising one or more hetero atoms selected from the group consisting of O, N, S, B, Si and P; C6-C1 0 aryl group; C3-C6 heteroaryl group; C3-C6 cycloalkyl group; C3-C6 heterocycloalkyl group; or combinations thereof. If the nucleophile has a pendant vinyl group, the vinyl group may be one of R1 , R2 or R3 or could be pendant from one or more of the R1 , R2 or R3 groups. Two or all three of the R1 , R2 and R3 moieties may be fused together.

Suitable nucleophiles include, but are not limited to trimethylamine, triethylamine, triisopropylamine, tri-n-butylamine, trimethylphosphine, triethylphosphine, triisopropylphosphine, tri-n-butylphosphine, triphenylphosphine, diphenylphosphinostyrene, allyldiphenylphosphine, diallylphenylphosphine, diphenylvinylphosphine, triallylphosphine, 2-dimethylaminoethanol, 1 - dimethylamino-2-propanol, 2-(isopropylamino)ethanol, 3-dimethylamino-1 - propanol, N-methyldiethanolamine, 2-(diethylamino)ethanol, 2-dimethylamino-2- methyl-1 -propanol, 2-[2-(dimethylamino)ethoxy]ethanol, 4-(dimethylamino)-1 - butanol, N-ethyldiethanolamine, triethanolamine, 3-diethylamino-1 -propanol, 3- (diethylamino)-l ,2-propanediol, 2-{[2-(dimethylamino)ethyl]methylamino}ethanol, 4-diethylamino-2-butyn-1 -ol, 2-(diisopropylamino)ethanol, N-butyldiethanolamine, N-tert-butyldiethanolamine, 2-(methylphenylamino)ethanol, 3-

(dimethylamino)benzyl alcohol, 2-[4-(dimethylamino)phenyl]ethanol, 2-(N- ethylanilino)ethanol, N-benzyl-N-methylethanolamine, N-phenyldiethanolamine, 2- (dibutylamino)ethanol, 2-(N-ethyl-N-m-toluidino)ethanol, 2,2'-(4- methylphenylimino)-diethanol, tris[2-(2-methoxyethoxy)ethyl]amine, 3- (dibenzylamino)-l -propanol, N-vinyl caprolactam, N-vinyl phthalimide, 9-vinyl carbazole, N-[3-(dimethylamino)propyl]methacrylamide or mixtures thereof.

The reaction between the nucleophile and the halogenated butyl rubber polymer may be carried out at a temperature in a range of from about 60 °C to about 250 °C. In one embodiment, the reaction between the nucleophile and the halogenated butyl rubber polymer may be carried out at a temperature about 80 °C to about 200 °C. In another embodiment, the reaction between the nucleophile and the halogenated butyl rubber polymer may be carried out at a temperature about 100°C to about 160°C. The reaction may be carried out for a time in a range of from about 0.5 to 90 minutes, preferably from 1 to 60 minutes, more preferably from 5 to 30 minutes. The amount of nucleophile reacted with the halogenated butyl rubber polymer may be in the range of from 0.01 to 5 molar equivalents, more preferably about 0.1 to 2 molar equivalents, even more preferably about 0.5 to 1 molar equivalents, based on the total molar amount of allylic halide present in the halogenated butyl rubber polymer. The resulting butyl rubber ionomer preferably possesses from about 0.01 to 10 mol%, more preferably from about 0.1 to 5.0 mol%, even more preferably from about 0.2 to 0.8 mol% of ionomeric moieties. The resulting butyl rubber ionomer may be a mixture of the polymer- bound ionomeric moiety and allylic halide such that the total molar amount of ionomeric moiety and allylic halide functionality are present in an amount not exceeding the original allylic halide content. Aggregates which are traditionally employed in the production of bituminous paving compositions include dense graded aggregate, gap-graded aggregate, open-graded aggregate, stone-matrix asphalt, recycled asphalt paving, and mixtures thereof. Drying and/or pretreating of the aggregate are optional. Aggregates or mineral aggregates can compromise coarse particulate materials used in construction, including sand, gravel, crushed stone, soil, slag, recycled concrete, or mixtures thereof.

As used herein, the term filler generally refers to particles that are added to a binder to lower the consumption of more expensive binder material and or to improve some properties of the resulting composition. Unless otherwise specified, the term filler means any inorganic or organic solid form of particle, particulate, aggregate, colloid or fiber that is not a binder material. The size of the particles that make up the filler of the present invention depends on the composition being prepared and physical properties desired. Examples of filler that may be suitable for use in the present invention are not particularly limited and include: mica, talc, aluminum, limestone dust, calcium sulfate, calcium carbonate, calcium oxide, magnesium oxide, crystalline silica, alumina, silicates, carbonates, sulfates, oxides or hydroxides which may or may not have a stoichiometric amount of a metal such as Na, Mg, Zn, Al, Ca, Ba and Fe; clays such as bentonites, kaolinites; aggregates such as sand; gravel, crashed stone, slag; minerals such as gypsum, borate, potash, vermiculite, flyash; organic materials such as acetates, nitrates, nitramines, aramid fibers, organic pigments, cellulosics, carbon black, carbon fibers, cellulose, nylon fibers, glass fibers, polyesther fibers, polytetrafluoroethylene, graphite and the like, as well as vegetation or other organic debris, such as straw, sawgrass, weeds, small organisms such as insects, and the like. In an embodiment, the filler is present in an amount of about 5-80%, preferably 10-60%, more preferably 20—50% and most preferably 30-40% by weight of the asphalt-polymer composition.

As used herein, the term oil generally refers to a variety of liquid or easily liquefiable, combustible substances that may be soluble in ether but not very soluble in water, and which are not naturally occurring in the asphalt. The oil of the present invention is not particularly limited and includes, for example animal, vegetable, fossil (petroleum) and synthetic oils. Preferably, the term oil refers to petroleum or petroleum based oil that may be either crude oil or oil at any stage of refinement. The oil may contain any combination of hydrocarbons, for example, paraffins, olefins, naphthenes, anthracenes, and high-boiling aromatics. In an embodiment, the oil may be present in an amount of about 0.5-30%, preferably, 0.5-25%, more preferably, 1 -20% by weight of the composition.

In an embodiment cross-linking agents or compatibilizers such as sulphur and the like are utilized. Cross-linking agents for asphalt applications are also well known in the art. As examples, U.S. Pat. No. 5,017,230, U.S. Pat. No. 5,756,565, U.S. Pat. No. 5,795,929 and U.S. Pat. No. 5,605,946 disclose various cross-linking compositions and refer to other patents that disclose cross-linking compositions. For various reasons including costs, environmental impact, and ease of use, elemental sulphur with inorganic zinc compounds are preferred. Most cross-linking formulations use elemental sulphur due to cost. In special situations, the sulphur can be added with a sulphur donor such as dithiodimorpholine, zinc thiuram disulfide, or any compound with two or more sulphur atoms bonded together. The zinc is added as zinc 2-mercaptobenzothiazole, zinc tetra alkylthiuram disulfide, zinc oxide, zinc dialkyl-2-benzosulfenamide, or other suitable zinc compound or mixtures thereof.

In addition to the foregoing, accelerators, free radical initiators, surfactants, dyes and other additives may be employed in the sealant for their recognized function.

In an embodiment of the present invention, the method encompasses the sealing of joints or cracks in concrete and/or asphalt structures. By "joints or cracks in concrete or asphalt structures" is meant any discontinuity or gap between a concrete or asphalt member of such structure and any adjacent member thereof. Said adjacent member may be concrete or asphalt or any other solid material to which the polysulfide adheres, including wood, plastic, rubber, metal, glass or other surface. Preferably, the adjacent surface is also asphalt or concrete. The method is particularly suitable for sealing joints or cracks in concrete structures such as roads, highways, parking lots, driveways, sidewalks, masonry and the like.

Hot Mix Asphalts (HMA) are made by heating and homogeneously blending an aggregate and asphalt binder, e.g., in a batch plant or a drum mix plant. During mixing, the hot asphalt binder must be readily able to coat the dried and heated mineral aggregate, given the shearing conditions employed, in a relatively short period of time (typically 30 to 90 seconds). Whilst the mixing temperature must be sufficiently high to allow rapid distribution of the asphalt binder on the aggregate, the use of the lowest temperature possible is advocated to avoid excessive oxidation of the bitumen. There are therefore upper and lower limits to mixing temperature. The material so produced is generally stored in silos before being discharged into trucks.

Typically, asphalt or rubber-asphalt sealers must be "hot-poured" at temperatures ranging from about 300+ and they are typically applied from double boiler, oil- jacketed melter applicators which are equipped with an agitator and separate temperature indicators for the oil bath and the melting vat.

The asphalt mixture may be hot poured or may be provided in a water- based emulsion which can be poured at ambient temperature. This is advantageous as it reduces the occurrence of accidents with the equipment required to apply the hot melt asphalt as well as the thermal degradation of the fillers and other additives in the asphalt composition. Using a water-based emulsion avoids some or all of these dangers and the expenses of the conventional hot-poured fillers. Generally, the emulsion is prepared by reaction of the asphaltic composition at an elevated temperature under reflux; the reaction product is then emulsified in an emulsification medium comprising water, a surfactant, and a thixotropic agent. The aqueous emulsion medium utilized in emulsifying either a chemically-modified asphalt or the asphalt-elastomer blend preferably is water containing from about 0.5 to about 20% by weight of a surfactant, an amount of surfactant ranging from about 1 to about 7% by weight being preferred. The surfactant can be cationic, anionic or non-ionic, cationic being preferred. The fatty amines, most desirably fatty primary monoamines, are particularly useful. A thickener or thixotropic agent such as a polyacrylaminde in an amount of 0.25 - 10 % is added to the emulsion medium as a viscosity control and as an aid in drying the emulsion in place after the emulsion has been used as a crack or joint filler.

Warm mix asphalt technology also allows for a reduction in temperature during the mixing, laying and compacting of asphalt pavements. This technology generally allows for a temperature reduction in the range of 10 - 40 °C. One approach includes the practice of foaming an asphalt binder (bitumen based) by introducing water into mixes at a temperature above 1 00 °C. Water containing zeolite or fillers and water-in-oil emulsion may also be added.

The preparation of a foamed asphalt binder composition entails initially heating the asphalt binder to a temperature sufficient to obtain a flowable substance. Such asphalt binders may be heated to a temperature from about 100 °C to about 180 °C. The addition of butyl ionomer defined in the present invention to a foamed asphalt binder composition may also show improvements in adhesion, tack and viscosity.

The addition of water injection or zeolite or filler containing water has a disadvantage that the stability of foamed bitumen is poor. In particular, the formed bubbles are large and break easily. As a result, expansion of the bitumen surface and its stabilization during mechanical mixing is very poor, resulting in only marginal improvements in coating and workability compared to normal hot mix. The addition of a charged polymeric additive such as the butyl ionomer has a positive influence on this.

Both hot melt asphalt and warm melt asphalt applications benefit from the addition of butyl ionomer due to the inherently charged polymeric materials. Charged anti-stripping additives such as organic amine or quaternary ammonium compounds (for example those described in US2013276668A1 ) can be used for warm melt asphalt compositions to form a stable foam that is exceptional for coating aggregates. Thus, without being bound by theory, it is believed the presence of such an ionomeric polymer species would have a similar effect on such asphalt compositions. Addition of a butyl ionomer as additive to asphalt based binders can allow for the hot melt or warm melt asphalt to be more easily mixed with, sprayed onto, poured, or otherwise coated to the outer surface of a variety of aggregates. The described modified binder may additionally interact more strongly with charged species leading to improved dispersion, and physical properties of the composite material. The presence of such a charged polymeric additive is also expected to increase the adherence to various additives such as sand, silica, aggregates, rocks, limestone and other fillers typically used for the production of such asphalt based applications

The modified asphalt compositions of the present invention may be used in variety of applications, including but not limited to a binder in asphalt pavement, hot mix road paving binder, crack filling and sealing on asphalt and concrete pavements (e.g. expressways, urban roads, airport tarmacs, parking lots, driveways and other high-traffic areas), hot pour crack and joint sealants or filler, paving emulsions, molded asphaltic plug joints for use in expansion joint sealing on asphalt concrete overlay and Portland cement concrete decks. It can also be used as a flashing cement on asphalt, concrete or metal roofs, on modified roofs (SBS and APP), skylights, chimneys, flashings, gutters, wall flashing and leaks in shingles. Additional applications may include below grade water and air barrier coatings as well as shingle underlayment on entire asphalt or metal roofing, shingles or roof panels including around critical areas such as eaves, valleys, ridges, dormers and skylights to protect structures and the interior from water penetration caused by ice dams and wind driven rain. Further applications include reflective roof coatings utilizing aluminum or other metallic or reflective fillers. More applications include peel-and-stick self-adhesive waterproofing membranes that are used for waterproofing bridge decks and other paved or structural surfaces before placement of hot mix asphalt concrete wearing surfaces for use in expansion, fixed end, and pressure relief joints, in both new construction or rehabilitation projects. Additionally, they could be used in a hot-applied polymer modified asphalt composition suitable for a variety of laminating and adhesive applications in the construction industry with such uses include packaging adhesives and roofing shingle laminating as well as waterproofing and water storage systems. The butyl ionomer would also be suitable in asphalt emulsions for corrosion protection applications to the coatings, linings and roofing industries for industrial coatings for refractory, water/wastewater, underbody coatings, RV and trailer manufacturing industries as well as in the heavy industrial, chemical process, pulp and paper, power, meat processing, dairy and pharmaceutical industries. Suitable coatings may be applied as mopping grade asphalts, cutbacks in solvents, single ply membranes, shingles, roll roofing membranes, etc.

The weight percent of the ionomeric copolymer in the total asphaltic composition is selected based on the desired physical properties of the resulting asphaltic composition and may be any suitable amount greater than zero. The current examples outline the positive effect of the addition of the modified butyl ionomer to a standard polymer modified asphalt formulation.

To one skilled in the art, such polymer modified formulations can involve a variety of different polymers types and amounts based on the desired properties of the final asphalt compound. It is anticipated that the addition of more than zero amount of the butyl ionomer to any representative asphaltic formulations would lead to benefits in one or more physical property including viscosity, adhesion, storage stability and tack. In addition, due to the improved adhesion noted, road reflectors may benefit due to increased adhesion to metal.

Asphaltic compositions according to the present invention exhibit surprising benefits in terms of adhesion, ductility, or a combination thereof, especially at ambient temperatures of less than or equal to 25 °C. For example, inventive compositions may exhibit adhesion of the composition to a concrete substrate that is greater by at least 30% as compared with the adhesion of an otherwise identical composition wherein the ionomeric copolymer is replaced with a linear SBS copolymer. The adhesion may be measured according to test methods as described herein. This adhesion value may be greater than 25%, greater than 20%, greater than 1 5% or greater than 10% as compared with the adhesion of an otherwise identical composition wherein the ionomeric copolymer is replaced with a linear SBS copolymer. Inventive compositions may exhibit ductility of the composition that is greater by at least 50% as compared with the ductility of an otherwise identical composition wherein the ionomeric copolymer is replaced with a linear SBS copolymer. The ductility may be measured according to test methods as described herein. This ductility value may be greater than 75%, greater than 100%, greater than 150% or greater than 200% as compared with the ductility of an otherwise identical composition wherein the ionomeric copolymer is replaced with a linear SBS copolymer. A combination of the foregoing properties may also be exhibited by the inventive composition. These properties and combinations of properties are advantageous in the previously recited uses of the asphaltic composition.

EXAMPLES

Materials: Bromobutyl 2030 (LANXESS Inc.), triphenylphosphine (BASF), AC-5 Asphalt (Marathon), Radial SBS (Kraton D1 184, Kraton and KTR 40, Dynasol), Linear SBS (Soloprene 1205), and calcium carbonate were used as received.

Testing: Testing was done in accordance to the ASTMs in Table 1 .

Table 1 .

Example 1: LANXESS Bromobutyl 2030 was combined with triphenylphosphine in an internal mixer. After mastication, the mixture was passed through a steam heated extruder. The resulting polymer was found to have an ionic content of 0.4 mol%.

Examples 2-3: The asphalt was heated to a stock temperature of 380-400 °F in a Ross high speed high shear mixer running at 2500-3000 rpm. Next the polymer was added and mixed until fully incorporated prior to adding filler and mixing for an additional 20 min. The resulting properties (Table 3) show that replacement of the radial SBS with Example 1 results in a compound with significantly higher adhesion to plywood as well as lower viscosity.

Table 2.

Table 3.

Examples 4-7: The asphalt was heated to a stock temperature of 380-400 °F in a Ross high speed high shear mixer running at 2500-3000 rpm followed by incorporation of oil and resin. Next the polymer(s) (as outlined in Table 4) was added individually until fully incorporated prior to adding filler and mixing for an additional 20 min. Comparison of Example 4 and Example 5 (Table 5) illustrate that replacement of the linear SBS with Example 1 results in a compound with significantly higher adhesion to plywood at both 77 F and 40 F as well as improved adhesion to glass and aluminum. Partial replacement of the linear SBS (Example 6) also showed improved adhesion over Example 4. Example 7 illustrates that replacement of the linear SBS with bromobutyl was detrimental to adhesion, demonstrating that it is the ionic functionality of Example 1 which provides adhesion benefits.

Table 4.

Table 5.

Examples 8-9: The asphalt was heated to a stock temperature of 380-400 °F in a Ross high speed high shear mixer running at 2500-3000 rpm followed by incorporation of oil and resin. Next the polymer(s) (as outlined in Table 6) was added individually until fully incorporated prior to adding filler and mixing for an additional 20 min. Comparison of Example 8 and Example 9 (Table 7) illustrate that replacement of the linear SBS with Example 1 results in a compound with significantly improved ductility and tensile adhesion.

Table 6.

Table 7.

Claims

1 . A polymer modified asphalt composition comprising, asphalt; an oil, a polymer additive; and an ionomer.

2. A polymer modified asphaltic composition according to claim 1 , wherein the asphalt is between 40 to 97% by weight of the composition, the oil is between 20 to 1 % by weight of the composition, the polymer additive is between 20 to 1 % by weight of the composition, and the ionomer is between 20 to 1 % by weight of the composition.

3. A polymer modified asphalt composition according to claims 1 or 2, wherein the ionomer is prepared by reacting a halogenated copolymer with at least one nitrogen and/or phosphorous based nucleophile to form an ionomeric butyl copolymer.

4. A polymer modified asphalt composition according to any one of claims 1 to 3, wherein the polymer additive comprises styrene-butadiene-styrene and/or styrene-butadiene polymers and/or polypropylene.

5. A polymer modified asphalt composition according to claims any one of claims 1 to 3, wherein the polymer additive is radial styrene-butadiene- styrene polymer.

6. A polymer modified asphalt composition according to any one of claims 1 to 5 wherein the at least one nitrogen and/or phosphorus containing nucleophile is according to the following formula,

wherein A is a nitrogen or phosphorus, R1 , R2 or R3 is selected from the group consisting of linear or branched C Ci₈ alkyl substituents, an aryl substituent which is monocyclic or composed of fused C₄-C₈ rings, and/or a hetero atom selected from a group consisting of B, N, O, Si, P, and S.

7. A polymer modified asphalt composition according to claim 6, wherein the at least one nitrogen and/or phosphorous based nucleophile comprises triphenylphosphine.

8. A polymer modified asphalt composition according to any one of claims 1 to

7, wherein the oil comprises animal, vegetable, petroleum or synthetic oil.

9. A polymer modified asphalt composition according to any one of claims 1 to

8, further comprising an organic or inorganic filler.

10. A polymer modified asphalt composition according to any one of claims 1 to

9, wherein the adhesion of the composition to a concrete substrate is greater by at least 30% as compared with the adhesion of an otherwise identical composition wherein the ionomer is replaced with a linear SBS copolymer.

1 1 . A polymer modified asphaltic composition according to any one of claims 1 to 10, wherein the ductility of the composition is greater by at least 50% as compared with the ductility of an otherwise identical composition wherein the ionomer is replaced with a linear SBS copolymer.

12. A shaped article comprising the polymer modified asphalt composition of claims 1 to 1 1 .

13. Use of the polymer modified asphalt composition according to any one of claims 1 to 1 1 in asphalt pavement, pavement crack filler, pavement sealant, hot pour crack and joint sealants or filler, paving emulsions, molded asphaltic plug joints, expansion joint sealing on asphalt concrete overlay, Portland cement concrete decks, flashing cement, air barrier coatings, shingle underlayment, waterproof membranes, asphalt emulsions or underbody coatings.

14. A method to seal a crack or joint in a concrete or asphalt structure comprising:

applying a sealant to the crack or joint, said sealant comprising

an asphalt,

an oil,

a polymer additive, and

an ionomer ,

said sealant applied in an amount sufficient to fill said crack or joint; and, curing said sealant under suitable conditions to cause bonding of the sealant to the crack or joint.

15. A method to prepare a hot mix asphalt composition comprising the steps of: heating ingredients comprising an asphalt, an oil, a polymer additive an aggregate and an ionomer, and

blending for a time sufficient to homogeneously mix the ingredients.