METHOD AND SYSTEM FOR REPAIRING POTHOLES IN ROADS

BACKGROUND

1. Field

The disclosure generally relates to a unique method and system for repairing potholes. In particular, the disclosure pertains to a lightweight portable polyurethane and/or polyisocyanurate foam used in combination with a ground anchoring and reinforcement system.

2. Discussion of the Background Art

Due to many environmental, usage and sabotage factors, significant damage to road surfaces can occur which create large holes or craters which make movement of vehicular traffic and the like extremely difficult or dangerous. Unfortunately, current techniques for repairing such potholes or craters is very time consuming, labor intensive, costly, material intensive and requires a substantial transportation investment. Accordingly, in remote areas or areas of high traffic flow it is not always practical or financially feasible to await for the delivery and slow repairs to such potholes, as the current technology provides.

Such current technology typically involves the use of either asphalt or concrete. As an example, a concrete repair requires delivery of the concrete mix and water directly to the repair site, which may, in many instances, not be practical or expeditious. Such concrete systems require the delivery of, in some instances, twelve 60 Ib. bags of concrete mix and 20 gallons of water. Another disadvantage is that it typically takes at least one day to cure, requiring monitoring during the cure period to avoid damage if used prior to curing.

The present disclosure provides numerous advantages over the asphalt and concrete systems of the prior art. In particular, this disclosure is portable (i.e., light weight and can be carried by the user without the need for special transportation equipment used to deliver to the repair site), inexpensive, and cures in a fraction of the time required by conventional repair systems.

The present disclosure also provides many additional advantages, which shall become apparent as described below.

SUMMARY

A system and method for repairing potholes which comprises: placing a securing mechanism within the existing pothole bottom or sidewalls, securing a reinforcing material to the securing mechanism to ensure its retention within the pothole, and filling or injecting a foam material to fill the pothole such that it encapsulates the securing mechanism and reinforcing material so that it is securingly retained within the potholes and substantially level to the surface of the roadway.

A preferred foam material is polyurethane and/or polyisocyanurate closed-cell foam prepared with a blowing agent comprising a hydrofluorocarbon selected from the group consisting of 1,1,1,3,3-pentafluoropropane, 1,1,1,2- tetrafluoroethane, 1 , 1 ,2,2-tetrafluoroethane, 1,1,1,3 ,3 -pentafluorobutane, 1 ,1,1 ,2,3,3,3-heptafluoropropane, and mixtures thereof.

The present disclosure includes a unique foam-based pothole repair method and kit, wherein the preferred foam is formed by a method of preparing polyurethane and polyisocyanurate foam compositions comprising the step of reacting and foaming a mixture of ingredients which react to form polyurethane or polyisocyanurate foams in the presence of a blowing agent comprising one or

more of the following: water, carbon dioxide, methyl formate, a hydrocarbon, and/or a hydro fluorocarbon; and an effective amount of a blowing agent additive. The foam can be a closed cell foam.

The additive is present in the amount of from about 0.02 to about 10 weight percent, based on the amount of blowing agent. Preferably, the additive includes α-methyl styrene. The α-methyl styrene is present in an amount of from about 0.02 to about 5 weight percent, based on the amount of blowing agent.

The blowing agent preferably comprises 1,1,1,3 ,3-pentafluoropropane and an effective amount of α-methyl styrene. The α-methyl styrene is present in the amount of from about 0.02 to about 5 weight percent, based on the amount of blowing agent. More preferably, the α-methyl styrene is present in the amount of from about 0.02 to about 2 weight percent, based on the amount of blowing agent.

Optionally, the closed cell foam containing a cell gas comprises a blowing agent as defined above.

Further objects, features and advantages of the present disclosure will be understood by reference to the following drawings and detailed description.

BRIEF DESCRIPTION OF THE DRAWINGS

Fig. 1 is an example of a pothole in a road surface;

Fig. 2 depicts a pair of securing members disposed within the pothole according to the present disclosure;

Fig. 3 depicts a reinforcing mesh disposed within the pothole and secured thereto by the pair of securing members according to the present disclosure;

Fig. 4 is an example of a two component polyurethane foam system which can be used according to the present disclosure;

Fig. 5 demonstrates the portability of the two component polyurethane foam system of Fig. 4; Fig. 6 demonstrates the application of the foam of the present disclosure to the secured reinforcing mesh of Fig. 3;

Fig. 7 depicts the finished foam pothole repair system according to the present disclosure; and

Fig. 8 demonstrates a vehicle traveling over a newly repaired pothole filled with the foam-based repair system according to the present disclosure.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENT

The present disclosure can best be described by referring to the figures, wherein Fig. 1 depicts a standard pothole or crater 1 disposed within a surface or roadway 3. Fig. 2 depicts the initial preparation of the repair system according to the present disclosure, wherein a securing mechanism, such as a pair of securing rods or stakes 5 are disposed or embedded within the bottom or sidewalls of a pothole 1 for the purpose of securing a reinforcing material 7, e.g., mesh or wire, within pothole 1.

Securing rods or stakes 5 can be made from any suitable material, such as metal, wood, plastic, etc., wherein the length will be dependent upon the size of the pothole being repaired.

Reinforcing material 7 can be any material which provides suitable reinforcement and/or strength to the foam material of the present disclosure. For example, reinforcing material 7 can be any mesh or wire configuration and can be made out of metal, synthetic material, rope, fabric, or plastic wood. One preferred reinforcing material 7 is a wire made into a grid, preferably a metal

wire. Optionally, reinforcing material 7 can be a rope made into the form of a grid.

Figs. 4 and 5 depict an optional canister based system having two canisters 9 and 1 1, a pair of hoses 13 and 15, and a spray nozzle 17, wherein hoses (13,15) are connected to canisters (9,11 ), respectively, at one end thereof, and connected to spray nozzle 17, at the other end. Fig. 6 demonstrates the use of the canister based system of Figs. 4 and 5 to inject a foam product 19 of the present disclosure into pothole 1 of roadway 3. Fig. 7 demonstrates a completed repair, wherein the reinforced foam 19 is substantially level to the surface of roadway 3. Finally, Fig. 8 demonstrates the strength of reinforced foam 19, as a vehicle 21 traverses thereover.

It is critical to the present invention that a foam material 19 be used that provides the quick set, strength and durability for roadways and the like. One preferred foam is recited in U.S. Patent No. 6,545,063, "Hydrofluorocarbon blown foam and method for preparation thereof," which is incorporated herein in its entirety.

The preferred foam material is a polyurethane and/or polyisocyanurate closed-cell foam. More particularly, this foam material includes the addition of α- methyl styrene, isobutanol and/or isopropanol to reduce vapor pressure, improve k-factor, enhance the solubility of the blowing agent in the premix and/or improve the processing characteristics of polyurethane and polyisocyanurate closed-cell foams prepared with a blowing agent. The blowing agent can be, but is not limited to, water, carbon dioxide, methyl formate, a hydrocarbon, and/or a hydrofluorocarbon selected from the group consisting of HCFC, HFC, low GWP HFC, e.g., 1 ,1,1,3,3-pentafluoropropane (HFC-245fa), 1,1 ,1 ,2-tetrafluoroethane (HFC-134a), 1,1 ,2,2-tetrafluoroethane (HFC-134), 1 ,1 ,1,3,3-pentafluorobutane (HFC-365mfc), 1 ,1 ,1,2,3,3,3-heptafluoropropane (HFC-227ea), and mixtures thereof.

The preferred foam of the present disclosure includes the addition of one or more of α-methyl styrene, isobutanol and/or isopropanol to the B-side of a polyurethane or polyisocyanuate foam formulation comprising a blowing agent comprising a hydrofluorocarbon selected from the group consisting of 1,1 ,1,3,3- pentafluoropropane, 1,1,1 ,2-tetrafluoroethane, 1 , 1 ,2,2-tetrafluoroethane, 1,1,1 ,3,3-pentafluorobutane, 1 ,1,1,2,3,3,3-heptafluoropropane, and mixtures thereof, resulting in reduced vapor pressure, improved k- factor, enhanced solubility of the blowing agent and/or improved processing characteristics of the foams. The addition of α-methyl styrene to the foam formulation results in improved thermal conductivity (k-factor) and thermal aging characteristics. With respect to thermal conductivity, the term "improved" refers to a decrease in the k- factor of the foam.

The polyurethane and polyisocyanurate foam compositions is preferably prepared by: reacting and foaming a mixture of ingredients which react to form polyurethane or polyisocyanurate foams in the presence of a blowing agent comprising a hydrofluorocarbon selected from the group consisting of 1,1,1,3,3- pentafluoropropane, 1,1 ,1 ,2-tetrafluoroethane, 1 , 1 ,2,2-tetrafluoroethane, 1 ,1,1 ,3,3-pentafluorobutane, 1,1,1,2,3,3,3-heptafluoropropane, and mixtures thereof, and an effective amount of a blowing agent additive ("additive") selected from the group consisting of α-methyl styrene, isobutanol, isopropanol, and mixtures thereof, preferably from about 0.02 to about 10 weight percent of said additive, based on the amount of blowing agent. In another embodiment, the method of preparing polyurethane and polyisocyanurate foam compositions comprises the step of reacting and foaming a mixture of ingredients which react to form polyurethane or polyisocyanurate foams in the presence of a blowing agent comprising 1,1,1 ,3,3-pentafluoropropane and α-methyl styrene, preferably from about 0.02 to about 5 weight percent α-methyl styrene, based on the amount of blowing agent.

In one embodiment, the closed cell foam is prepared from a polymer foam formulation containing a blowing agent comprising 1,1,1,3,3-pentafluoropropane and α-methyl styrene, preferably from about 0.02 to about 5 weight percent α- methyl styrene, based on the amount of blowing agent.

In another embodiment, the closed cell foam contains a cell gas comprising a blowing agent comprising a hydro fluorocarbon selected from the group consisting of 1,1,1 ,3,3-pentafluoropropane, 1 , 1 , 1 ,2-tetrafluoroethane, 1 ,1 ,2,2-tetrafluoroethane and mixtures thereof and an additive selected from the group consisting of α-methyl styrene, isobutanol, isopropanol and mixtures thereof, preferably from about 0.02 to about 10 weight percent of said additive, based on the amount of blowing agent. In one embodiment, the closed cell foam contains a cell gas comprising a blowing agent comprising 1,1 ,1,3,3- pentafluoropropane and α-methyl styrene, preferably from about 0.02 to about 5 weight percent α-methyl styrene, based on the amount of blowing agent.

The preferred blowing agent composition comprises a hydrofluorocarbon selected from the group consisting of 1,1,1 ,3,3-pentafluoropropane, 1,1,1 ,2- tetrafluoroethane, 1,1,2,2-tetrafluoroethane, 1,1,1,3,3-pentafluorobutane,

1,1,1 ,2,3,3,3-heptafluoropropane, and mixtures thereof, and an additive selected from the group consisting of α-methyl styrene, isobutanol, isopropanol, and mixtures thereof, preferably from about 0.02 to about 10 weight percent of said additive, based on the amount of blowing agent. In one embodiment, the closed cell foam contains a cell gas comprising a blowing agent comprising 1,1,1,3,3- pentafluoropropane and α-methyl styrene, preferably from about 0.02 to about 5 weight percent α-methyl styrene, based on the amount of blowing agent.

As used herein, an effective amount of additive means an amount, based on the amount of blowing agent, which reduces the vapor pressure of a foam

formulation B-side to below the vapor pressure of the corresponding foam prepared in the absence of additive. Generally, an effective amount is from about 0.02 to about 10 weight percent, based on the amount of blowing agent. For example, α-methyl styrene is preferably added in an amount of from about 0.5 to about 2 weight percent, based on the amount of blowing agent.

As used herein, blowing agent composition refers to HFC-245fa or HFC- 134a singly or in combination with other non-ozone depleting blowing agents, such as, for example, other hydrofluorocarbons, e.g., difluoromethane (HFC-32), difluoroethane (HFC-152), trifluoroethane (HFC- 143), tetrafluoroethane (HFC- 134), pentafiuoropropane (HFC-245), pentafluorobutane (HFC-365), hexafluoropropane (HFC-236), and heptafluoropropane (HFC-227); C ₄ C ₇ hydrocarbons, including but not limited to butane, isobutane, n-pentane, isopentane, cyclopentane, hexane and isohexane; inert gases, e.g., air, nitrogen, carbon dioxide; and water, in an amount of from about 0.5 to about 2 parts per 100 parts of polyol. Where isomerism is possible for the hydrofluorocarbons mentioned above, the respective isomers may be used either singly or in the form of a mixture.

HFC-245fa is a known material and can be prepared by methods known in the art such as those disclosed in WO 94/14736, WO 94/29251 , WO 94/29252 and U.S. Pat. No. 5,574,192. Difluoroethane, trifluoroethane, tetrafluoroethane, pentafiuoropropane, pentafluorobutane, hexafluoropropane and heptafluoropropane are available for purchase from Honeywell, Inc., Morristown, New Jersey, USA. The α-methyl styrene, isobutanol and isopropanol components of the disclosure are also commercially available.

With respect to the preparation of rigid or flexible polyurethane or polyisocyanurate foams using a blowing agent comprising 1 ,1 ,1 ,3,3- pentafiuoropropane or 1 ,1 ,1 ,2-tetrafluoroethane, any of the methods well known

in the art can be employed. See Saunders and Frisch, Volumes I and II Polyurethanes Chemistry and Technology (1962). In general, polyurethane or polyisocyanurate foams are prepared by combining under suitable conditions an isocyanate (or isocyanurate), a polyol or mixture of polyols, a blowing agent or mixture of blowing agents, and other materials such as catalysts, surfactants, and optionally, flame retardants, colorants, or other additives.

It is convenient in many applications to provide the components for polyurethane or polyisocyanurate foams in pre -blended foam formulations. Most typically, the foam formulation is pre-blended into two components. The isocyanate or polyisocyanate composition comprises the first component, commonly referred to as the "A" component or "A-side." The polyol or polyol mixture, surfactant, catalysts, blowing agents, flame retardant, water and other isocyanate reactive components comprise the second component, commonly referred to as the "B" component or "B-side." While the surfactant and fluorocarbon blowing agent are usually placed on the polyol side, they may be placed on either side, or partly on one side and partly on the other side. Accordingly, polyurethane or polyisocyanurate foams are readily prepared by bringing together the A and B side components either by hand mix, for small preparations, or preferably machine mix techniques to form blocks, slabs, laminates, pour-in-place panels and other items, spray applied foams, froths, and the like. Optionally, other ingredients such as fire retardants, colorants, auxiliary blowing agents, water and even other polyols can be added as a third stream to the mix head or reaction site. Most conveniently, however, they are all incorporated into one B component.

The α-methyl styrene, isobutanol and isopropanol additives of the present invention may be added to B-side of the foam formulation, or to the blowing agent per se, by any manner well known in the art.

Any organic polyisocyanate can be employed in polyurethane or polyisocyanurate foam synthesis inclusive of aliphatic and aromatic polyisocyanates. Preferred as a class are the aromatic polyisocyanates. Preferred polyisocyanates for rigid polyurethane or polyisocyanurate foam synthesis are the polymethylene polyphenyl isocyanates, particularly the mixtures containing from about 30 to about 85 percent by weight of methylenebis(phenylisocyanate) with the remainder of the mixture comprising the polymethylene polyphenyl polyisocyanates of functionality higher than 2. Preferred polyisocyanates for flexible polyurethane foam synthesis are toluene diisocyanates including, without limitation, 2,4-toluene diisocyanate, 2,6-toluene diisocyanate, and mixtures thereof.

Typical polyols used in the manufacture of rigid polyurethane foams include, but are not limited to, aromatic amino-based polyether polyols such as those based on mixtures of 2,4- and 2,6-toluenediamine condensed with ethylene oxide and/or propylene oxide. These polyols find utility in pour-in-place molded foams. Another example is aromatic alkylamino-based polyether polyols such as those based on ethoxylated and/or propoxylated amino ethyl at ed nonylphenol derivatives. These polyols generally find utility in spray applied polyurethane foams. Another example is sucrose-based polyols such as those based on sucrose derivatives and/or mixtures of sucrose and glycerine derivatives condensed with ethylene oxide and/or propylene oxide. These polyols generally find utility in pour-in-place molded foams.

Typical polyols used in the manufacture of flexible polyurethane foams include, but are not limited to, those based on glycerol, ethylene glycol, trimethylolpropane, ethylene diamine, pentaerythritol, and the like condensed with ethylene oxide, propylene oxide, butylene oxide, and the like. These are generally referred to as "polyether polyols." Another example is the graft copolymer polyols which include, but are not limited to, conventional polyether polyols with vinyl polymer grafted the polyether polyol chain. Yet another

example is polyurea modified polyols which consist of conventional polyether polyols with polyurea particles dispersed in the polyol.

Examples of polyols used in polyurethane modified polyisocyanurate foams include, but are not limited to, aromatic polyester polyols such as those based on complex mixtures of phthalate-type or terephthalate-type esters formed from polyols such as ethylene glycol, diethylene glycol, or propylene glycol. These polyols are used in rigid laminated boardstock, and may be blended with other types of polyols such as sucrose based polyols, and used in polyurethane foam applications.

Catalysts used in the manufacture of polyurethane foams are typically tertiary amines including, but not limited to, N-alkylmorpholines, N- alkylalkanolamines, I^N-dialkylcyclohexylamines, and alkylamines where the alkyl groups are methyl, ethyl, propyl, butyl and the like and isomeric forms thereof, as well as heterocyclic amines. Typical, but not limiting, examples are triethylenediamine, tetramethyl ethyl enediamine, bis(2-dimethylaminoethyl)ether, triethylamine, tripropyl amine, tributylamine, triamylamine, pyridine, quinoline, dimethylpiperazine, piperazine, N,N-dimethylcyclohexylamine, N- ethylmorpholine, 2-methylpiperazine, N,N-dimethylethanolamine, tetramethylpropanediamine, methyltriethylenediamine, and mixtures thereof.

Optionally, non-amine polyurethane catalysts are used. Typical of such catalysts are organometallic compounds of lead, tin, titanium, antimony, cobalt, aluminum, mercury, zinc, nickel, copper, manganese, zirconium, and mixtures thereof. Exemplary catalysts include, without limitation, lead 2-ethylhexoate, lead benzoate, ferric chloride, antimony trichloride, and antimony glycolate. A preferred organo-tin class includes the stannous salts of carboxylic acids such as stannous octoate, stannous 2-ethylhexoate, stannous laurate, and the like, as well as dialkyl tin salts of carboxylic acids such as dibutyl tin diacetate, dibutyl tin dilaurate, dioctyl tin diacetate, and the like.

In the preparation of polyisocyanurate foams, trimerization catalysts are used for the purpose of converting the blends in conjunction with excess A component to polyisocyanurate-polyurethane foams. The trimerization catalysts employed can be any catalyst known to one skilled in the art including, but not limited to, glycine salts and tertiary amine trimerization catalysts, alkali metal carboxylic acid salts, and mixtures thereof. Preferred species within the classes are potassium acetate, potassium octoate, and N-(2-hydroxy-5-nonylphenol) methyl-N-methylglycmate.

Also included in the mixture are blowing agents or blowing agent blends. Generally speaking, the amount of blowing agent present in the blended mixture is dictated by the desired foam densities of the final polyurethane or polyisocyanurate foams products. The polyurethane foams produced can vary in density, for example, from about 0.5 pound per cubic foot to about 40 pounds per cubic foot, preferably from about 1 to about 20 pounds per cubic foot, and most preferably from about 1 to about 6 pounds per cubic foot. The density obtained is a function of how much of the blowing agent, or blowing agent mixture, is present in the A and/or B components, or that is added at the time the foam is prepared. The proportions in parts by weight of the total blowing agent or blowing agent blend can fall within the range of from 1 to about 60 parts of blowing agent per 100 parts of polyol. Preferably from about 10 to about 35 parts by weight of blowing agent per 100 parts by weight of polyol are used.

Dispersing agents, cell stabilizers, and surfactants may be incorporated into the blowing agent mixture. Surfactants, better known as silicone oils, are added to serve as cell stabilizers. Some representative materials are sold under the names of DC-193, B-8404, and L-5340 which are, generally, polysiloxane polyoxyalkylene block co-polymers such as those disclosed in U.S. Patent Nos. 2,834,748, 2,917,480, and 2,846,458.

Other optional additives for the blowing agent mixture may include flame retardants such as tris(2-chloroethyl)phosphate, tris(2-chloropropyl)phosphate, tris(2,3-dibromopropyl)phosphate, tris(l,3-dichloropiOpyl)phosphate, diammonium phosphate, various halogenated aromatic compounds, antimony oxide, aluminum trihydrate, polyvinyl chloride, and the like.

The foam kit includes the polyurethane foam system with disposable spray nozzle or dispensing apparatus or non-disposable dispensing apparatus. Surfacing compounds are optional, e.g., dirt, paint, asphalt or other coating disposed on top of the installed foam material.

While I have shown and described several embodiments in accordance with my invention, it is to be clearly understood that the same may be susceptible to numerous changes apparent to one skilled in the art. Therefore, I do not wish to be limited to the details shown and described but intend to show all changes and modifications that come within the scope of the appended claims.