CA1037706A - Heat - and electromagnetic radiation-reflecting composition - Google Patents

Abstract

Abstract of the Disclosure Petroleum derived oil-modified polyurethane compositions incor-porating heat-reflecting and/or e.m. radiation reflecting agents are dis-closed. The compositions may be employed for insulating and protecting a variety of surfaces, substrates and areas, particularly in connection with application to tundra and permafrost. The compositions may also be used to prevent undue expansion and contraction on structures of all types such as runways or roadways, canals, beams, etc. to thereby prevent dis-tortion and cracking; and to prevent deterioration by the sun's rays react-ing on a substrate. The compositions reflect infrared rays from the surface and thereby prevent damage to structures from expansion and contraction or distortion caused by the sun's rays.

Description

- ` -: ~037706 , :
The present invention relates to a method of insulating and pro-tecting a variety of surfaces and substrates, including tundra and perma-frost regions, roadways, runways, areas, buildings, dams, canals, beams, etc. from expansion and contraction, stresses, cracking and deterioration by the sun's rays, and in particular to a petroleum derived oil-modified polyurethane composition incorpora~ing a heat-reflecting agent and/or e.m. radiation reflecting agent.
Problems have been encountered in working in areas where perma-frost exists, for example, on the north slope of Alaska and in Northern Canada. Permafrost is perennially frozen ground found in the Artic regions.
The permafrost zone may contain some layers of gravel free of ice known ~ as "dry permafrost", but the bulk of the zone is usually composed of - sand and rocks or of unconsolidated aggregates of sand, silt and gravel ; in which interstitial water is frozen to ice. Permafrost also contains ice lenses and/or layers of almost pure ice. Permafrost is formed by the spreading downward of the low temperatures found at the surface in Artic winters, particularly in regions of low snowfall. There is seasonal thaw-ing and freezing at the surface, but thawing rarely penetrates more than 18 inches where the permafrost is protected by tundra or vegetation. The `~
downward spread of freezing temperatures to form permafrost continues ;
until an equilibrium is reached with heat flow from the earth's interior.
The thickness of the permafrost 70ne varies with latitude and with particular geographic location. Permafrost is not believed to exist under most deep large Artic lakes or under the Artic Ocean. Permafrost consists of both a frozen matrix of water and soil and lenses of ice without any soil. This zone extends in thickness from a few feet to two thousand feet or more. It is said to be almost a mile deep in Siberia. When the permafrost section is frozen it is a rigid mass. However, upon thawing, the thawed portion becomes rather fluid. Ordinarily this thawing under natural conditions only takes place to a depth of not over about five feet 1~)37706 ~:
in the summer and then it refreezes in the winter. Thawing in the perma-frost will cause subsidence. This subsidence can impose stresses and strains on structures such as roadways, runways, buildings and foundations which have depended upon the rigidity of frozen permafrost for their support.
The surface layer which overlays the permafrost is of course frozen during the ~inter when temperatures sometimes approach minus 70F.
Nevertheless summer temperatures in these regions can reach into the 70's ; and 80's. During the summer, when the surface layer overlaying the perma-frost has melted, a delicate relationship exists between the surface layer and the ground beneath it. It has been found that compressions of any sort, even footprints may leave long-lasting scars. In fact, State regulations in Alaska require that vehicles stay off the thawed surface during the summer, except for emergencies and scientific projects. Other-wise, ground transportation is undertaken only in winter, when the sur-face is frozen. Clearly, an effective method of insulating and protect-ing permafrost regions from thawing is needed.
The present inventive method of insulating and protecting a variety of areas, surfaces and substrates, is particularly intended for protecting the tundra and permafrost regions from thawing. A petroleum derived oil-modified polyurethane composition incorporating a heat and/or e.m. radiation reflecting agent is used for this purpose. The polyurethane composition may be used for a great variety of other purposes.
The petroleum oil-modified polyurethane compositions of the present invention may incorporate a wide variety of filler materials.
For example, sand, gravel, rock, muskeg, sawdust, woodpulp, clays, vermi-culite, flyash, cinders, coal, mud, crushed glass, sulphur, grainsJ fibers .
; of all types as well as many other materials whether found in nature or a product of manufacture may be used as fillers. Thus the present invent-ion further provides synthetic resin compositions made from readily avail- ~ -- 30 able materials useful for the purpose of protecting the ecology and for ~ ~03~06 purposes of providing an economical construction material.
According to the present invention there is provided a method of insulating, stabilizing and protecting tundra and permafrost from thawing and -- unwanted subsidence which comprises applying to a surface a composition which includes about 10 to about 90% by weight of hydrocarbon oil, about 90 to about 10% by weight of polyurethane prepolymer, and a solar radiation reflecting agent, said composition being applied in sufficient amount to coat said sur-face which is either permafrost or a substrate on permafrost, and permitting said composition to harden, whereby said composition acts to reflect solar radiation from said surface, to prevent thawing of said permafrost.
In another aspect, the present invention comprises a composition for treating tundra and permafrost to reduce thawing and subsidence thereof comprising about 10 to about 90% by weight of a hydrocarbon oil, about 90 to about 10% by weight of a polyurethane prepolymer, a catalyst for said pre-polymer and a solar energy reflecting agent.
The inventive composition reflects infrared rays and thereby prevents damage to permafrost as well as preventing cracking, distortion or deterioration of other substrates to which it may be applied such as runways, roadways, areas, beams, or canals due to expansion and contraction. The re-flecting composition may be placed between structures and objects aboveambient temperatures such as automobile roadways, aeronautical runways, building floors and walls, foundations, or a permafrost surface thereby to prevent thawing of the permafrost and other areas or structures and consequent damages.
The inventive composition will of course also reflect visible, artificial light thereby aiding the illumination of automobile roadways, aeronautical runways and structures at night by means of reflected light.
The new and useful compositions comprise a particular petroleum derived oil, a urethane polymer which will set at ambient temperatures as well as at elevated temperatures and a reflecting agent. It has been found that the composition of a petroleum derived oil having a boiling range within the temperature range of 230 to 580C and preferably 260 to 550C is suitable for ~ ~ _ 3 _ :

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the invention. The petroleum derived oil generally is aromatic and/or naphthenic in character. In the use of urethane prepolymers and a polymer and a polymer forming agent, the urethane prepolymers are polymerized in situ in the petroleum derived oil. Compositions prepared according to the present invention have been found to cure at ambient temperatures ", ~ ~ ''''"

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~037706 (20C to 40C) as well as at elevated temperatures.
The term urethane is used herein in a broad generic sense to include the well known classes of monomeric materials which contain at least one urethane linkage. The term is intended to include compositions which may also contain other types of linkage such as vinyl-modified ure-thanes and polyes~er-modified urethanes. The urethanes in this invention may be self-curing or may be cured by means of well known catalysts for polyurethanes such as tertiary amines, inorganic acids like sulphuric acid and phosphoric acid, metallic carbonyl compounds, nickel carbonyl compounds and phosphines. Included are polyurethanes prepared from poly-isocyanates and polyesters and polyethers.
In addition, urethanes also include adducts of polyisocyanates with other materials having reactive components such as castor oil, linseed oil, soya oil and the like, polyols obtained by polymerising compounds containing ethylene oxide groups, polyester containing hydroxyl groups, obtained by condensing aromatic and/or aliphatic glycols with aromatic and/or aliphatic carboxylic acids. Also included are isocyanates con-densed with hydroxy compounds such as allyl alcohol and the like wherein the polymer structure comprises linear and/or cross linked hydrocarbon groups formed by reactions in addition to the urethane reaction.
The preferred urethanes are those which may be produced by the well known reaction between organic isocyanates or polyisocyanates and monofunctional or poly-functional hydroxy compounds. It is further pre-ferred that the urethanes be prepared from polymeric polyisocyanates con-taining urethane linkages that may be obtained by reacting an excess of a monomeric polyisocyanate with a monomeric or polymeric polyfunctional hydroxy compound although monomeric polyisocyanates are equally appli-cable. Polyurethane resins cross linked with polythic ethers and vinyl-idene may also be used.
Catalyst compounds such as bismuth nitrate, lead-2-ethylhexoate, ~ , 10377~6 lead benzoate, lead oleate, sodium trichlorophenate, tetrabutyltitanate, ferric chloride, stannous octoate, stannous oleate, butyltin trichloride, magnesium stearate and tertiary amines such as triethylene diamine may be used for purposes of this invention. Other catalysts for the reaction may also be used.
The proportions of filler to petroleum derived oil will vary considerably depending upon the final use for the product. The filler, if any, is added in an amount ranging from 5 to 35% by weight, based on the total weight of composition.
For the present invention, an aromatic oil is defined as one in which at least 55% of the carbon atoms occur in benzene or condensed benzene ring structures. A naphthenic oil for the purpose of the present invention is one containing less than 55% by weight of aromatics and more than 60%
by weight combined aromatics and naphthenes but no less than 35% by weight -of naphthenes. Such oils as these contemplated herein may be obtained from petroleum refinery streams by the solvent extraction or distillat-ion of heavycatalytic cycle oils, light catalytic cycle oils, lube oils, gas oils, and thermally cracked residues. The light catalytic cycle oils represent a heavy material somewhat comparable in molecular weight to diesel fuel, and is the fraction produced by catalytic cracking which is immediately below the heavy catalytic cycle oil in boiling point. Regard-less of the method whereby the aromatic or naphthenic oils are obtained it will be generally preferred that they have the following physical properties:
boiling range of 260 to 550 at 760 mm. Hg.
specific gravity of 0.93 to 1.11 at 60/60F.
refractive index of 1.50 to 1.68 at 20C.
Thus, particular useful oils are as follows: a Furfural extract of petro-leum refinery heavy catalytic cycle oil having the following properties:
specific gravity C60~60F~ 1.07 ~037706 .
boiling range, 95-260C at 2 mm Hg.
refractive index ~20C) 1.64 A select cut of a furfural extract of a heavy petroleum lube oil having the following properties:
boiling range 187-208C at lO mm Hg.
specific gravity 1.04 (60)F.
refractive index (20C) 1.625. ~;
Well head crude oils may also be used.
The useful materials of this invention generally are comprised of from 10 to about 90% by weight of the petroleum derived oil and from about 90 to 10% by weight of a urethane polymer. However, for most applications the preferred compositions are those comprised of from 10 to about 50% by weight of urethane polymer.
The most useful compositions of the present invention are comprised of approximately from 20 to 40% by weight of the petroleum derived oil and 80 to 60% by weight of a urethane polymer.
The amount of reflecting agent incorporated into the composition may vary widely. However, relatively small amounts are required, about one pound of agent in a composition is sufficient to cover a conventional sized runway or airstrip. Similarly the amount of the composition to be applied to a substrate will depend upon the ultimate use, weight to be supported, etc.
The method of preparing the composition of the present invent-ion comprises intimately mixing the petroleum derived oil and a urethane polymer or urethane polymer forming materials.

Generally this will be carried out by comingling the petroleum 1~ ~ a~
~Ll derived oil and urethane polymer or polymer forming materialsi~}~ then allowing the reaction mass to set. The mixing of these components may be carried out at virtually any temperature though generally ambient temp-erature C2Q to 4QC) are preferred from a practical standpoint. HoweverJ

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' `; elevated temperatures may be used. The curing of the petroleum derived ;
oil urethane polymer compositions is carried out at temperatures ranging from ambient temperatures up to and including temperatures as high as 125C and higher. Generally, the higher the temperature, the more rapid is the curing.
Other aspects, objects, and advantages of this invention will ~ `
: be apparent to those skilled in the art from the following detailed description thereof.
According to one feature of the invention, a thermally insulat-ing and reflecting oil-modified polyurethane composition is provided com-prising a polyurethane prepolymer, an effective amount of an e.m. radiat-ion or heat-reflecting agent, an appropriate curing catalyst for the pre-polymer capable of converting the prepolymer into a resin and a selected amount of a petroleum derived oil as defined above. The resulting oil-modified polyurethane compositions are relatively inexpensive, able to withstand exposure to the sun's rays without deterioration, high or low temperatures without buckling or cracking, flexible, resilient, exhibit great compressive strength and tensile strength, can be easily sawed, drilled, nailed or screwed and may be readily joined to existing structure. The polyurethane compositions are waterproof and able to withstand the effects of acids, oils and corrosive solvents.
Polyurethane prepolymers are the condensates resulting from, for example, the reaction of a polyhydroxylated alkane with an excess of an aromatic or aliphatic di- or poly-isocyanate at temperatures ranging from about 50-120C for 1/2 to 4 hours. The condensation react-ion can be conducted in the presence of an inert solvent or the solvent can be dispensed with. Suitable polyhydroxylated alkanes have from 2-8 free hydroxyl groups and a molecular weight of between 200-1,000. An excess of diisocyanate in an amount over and above the quantity is required by stoichometry to react with each of the free hydroxyl groups - "
` 1037~06 of the polyhydroxylated reactant. A catalyst may not be necessary for the condensation reaction because of the high reactivity of the react-ants. In order to produce a prepolymer having long-term stability, it is desirable to have a slight acidity. Control of the acidity can be achieved by methods known in the art.
Among the many polyhydroxylated reactants which may be used are the carbohydrates, glycols and polyglycols including the tri-, tetr-, pent-, hex-, hept- and octols and their derivatives. More specifically, suitable polyhydroxylated reactants include ethylene, pro-pylene and butylene glycols, hexanediol, methylhexanediol, diethylene glycol, glycerol, trimethyol ethane, trimethylol propane, 1,2,4-tri-hydroxyl-butane triethanolamine, 4-methyl, 3-cyclohexene, l,l-dimethanol, pentaerythritol, mannitol, sorbitol, sucrose, and methyl glucoside.
Polyesters may also be used for reaction with the poly-cyanates. Suitable polyesters may be obtained from polyfunctional acids and polyols such as the adipates, succinates, sebacates, azelates and phthalates as well as pentaerythritol, xylitol and sorbitol. It is desirable that the polyols have a hydroxyl number of at least 250 and preferably at least 350.
The isocyanate co-reactant of the polyurethane prepolymer - component can be aromatic, aliphatic, heterocyclic or cyclic. Among the satisfactory di-isocyanates that can be used are: hexyl and octyl diisocyanate, tetramethylene, tetraethylene, pentamethylene, octamethylene, and dodecamethylene diisocyanates, 3,3-diisocyanate dipropylether, cyclo-- hexyl diisocyanates, the xylylene diisocyanates, diphenylmethane 4,4'-diisocyanate, B,B'-diphenylpropane 4,4'-diisocyanate unadecamethylene ; diisocyanates, methaphenyl diisocyanate, p-phenyl diisocyanate, l-methyl phenylene 2, 4-diamine naphthalene 1, 4-diisocyanate, 2,8 and 2,6-toluene diisocyanate, 1,3,5-benzene triisocyanate, tetrahydrofurfuryl diisocyanate, 4-chloro-1, 3 penylene diisocyanate, 4,4-biphenylene diisocyanate, 1,5-.

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naphthalene diisocyanate, 1,4-cyclohexylene diisocyanate, 4,4'-methylene bis-(cyclohexyl-isocyanate), and polyarylpolyisocyanate, and mixtures thereof.
Because of availability, the preferred diisocyanate reactants are the aryl isocyanates such as ben~ene, toluene, xylene, di- and poly-isocyanates.
To the polyurethane prepolymer is added a suitable catalyst.
Catalysts for these polyurethane prepolymers are well known in the art and include compounds such as bisrnuth nitrate, lead tertiary-ethylhexo-ate, lead ben~oate, lead oleate, sodiumtrichlorophenate, tetrabutyl-titanate, ferric chloride, stannous octoate, stannous oleate, butyltin-trichloride and tertiary amines such as triethylene diamine. Many other - catalysts are known in the art for this purpose.
In equal amount with oil it is found that the composition can be made soft and ductile by using lesser amounts of catalyst. One test was conducted with only about five drops of the catalyst in one gallon of oil at approximately seventy degrees F. The material throughout became like a heavy gum in about four hours.
It is a feature of this invention that a heat-reflecting agent incorporated in the above-described oil modified polyurethane prepolymer composition can be compatible with the various types of hydrocarbonaceous oils which may be used. It has been found that a preferred heat-reflecting agent is 4,4'-bis (3 phenyl-ureido)-2,2' stilbenedisulfonic acid. This chemical is found as the active ingredient in heat-reflect-ing agents sold commercially under the Trade Marks Pontamine and Calcofluor; (see British Patent 683,895, German Patent 746,569 and French Patent 878,155). The materials are of the general class of substances of the formula:
~ N \
- Ar N - G - X
N

_g_ ,, , . : : ,: , .

1~)3770~
wherein Ar is an aromatic group linked to the triazole group by two adjacent carbon atoms and G is an aromatic group which in combination with the two groups attached imparts substantivity whereas X is an aromatic group which is linked to G by means of a heterocyclic system such as:
/ N~
-N ¦ or -C ¦
N- S-said compound carrying sulfonic acid groups and being substantive towards the said material.
The heat-reflecting compounds may be derived from amines such as dihydrothiotoluidine sulphonic acid, benzidine or diaminostilbenedi-sulphonic acid. Examples of the compounds are 4,4'-bis-(5'-sulphonaptho-1', 2' : 4,5-triazolyl-(2))-stilbene-2,2'-disulphonic acid; 2-~4'-(5'-sulphonaptho-l', 2' : 4,5-triazolyl-(2))-phenyl)-6-methylbenzthiazole sulphonic acid. The compounds derived from stilbene are distinguished by a particular strength. The compounds in question may be obtained by diazotising or tetrazotising the said amines in the usual manner, coupling the diazo or tetrazo compounds with amines, which couple in a position adjacent to the amino group -- for instance with 2-amino napthalene or its sulphonic acids or their substitution products, with esters or arylides of 3-amino crotonic acid -- and converting the orthoamino azo compounds thus obtained in known manner into the triazoles.
Foaming or blowing agents may be also incorporated into the admixture of reactants whenever appropriate.
Foaming agents useful in the practice of the invention include low-boiling compounds such as CCC13F, CC12FCClF2, CClF2CClF2, CBrF2CBrF2 and mixtures thereof. Any substance that will cause foaming of the pre-polymer components and their curing systems can be employed. These include water, inert ~ases, and solids. The gaseous group of foaming agents .

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10377~6 ... . .
- includes azo, diazo or other nitrogen containing foaming agents. When a solid is used as the foaming agent, the decomposition temperature of the solid must be exceeded by the temperature of the composition during the mixing and application thereof.
A unicelled foam of the composition can be formed by the addition of the foaming agents or water depending on the type of oils being used, as for instance, when using number six bunker fuel as an oil the use of water works well as a foaming agent. The foaming agents can also be introduced in the form of gases. Nitrogen may be used very effectively. A large mass of the polyurethane composition can be made to foam in water, allowed to set, and then more composition can be made into foam alongside of the original mass, all underwater. Both masses of foam so made may be subsequently joined together. The foam -~ -so made is all of unicelled construction and because of its very light weight it has a very high bouyancy factor. The cell size of the foam is controlled by the amount of foaming agent used. The foam can also be ; made to resist fire or burning by the addition of a fire retardant. The percentage to be applied to the composition being about the same as for the material when used for other purposes than as a foam. As the mass of foam joins together underwater as well as above water one mass is formed against another which is already formed, it is possible to thus build a large floating mass which can be used to support structures of almost any type.
In its process aspects, it has been determined that the best method of application is to spray the material, as for instance, for the use on roadways, runways, embankments, dams, tunnels, beams, subways, mineshafts, canals, penstocks. Other applications include areas such as a tarmac, heliport, floors to replace concrete in buildings such as in a hanger or storage yards and numerous other applications where the composition can be allo~ed to soak into the material to be hardened or . . , : , . : . . , sealed. ~037706 ~:
When used, as for instance, to build walls, pipe such as sewer or water pipes or any other type of construction where forms have to be used the curing of the composition should be retarded by using less catalyst to thereby retard the setting rate of the composition thus allowing time for handling.
When used as a paint, the composition could also be sprayed on through a mixing nozzle whereby the oil containing the catalyst is mixed with the prepolymer only moments before it hits the surface to be painted. Underwater surfaces can best be painted through the brush or roller method. The composition adheres readily to a wet surface. From experience, it has been found that a surface painted with the present composition and subjected to conditions whereby barnacles normally attached themselves remained free of barnacle formation.
The economics of using the composition of this invention especially in remote areas is of great importance because all materials at hand may be used as filler, including gravel, unwashed sand, shales, stone fragments, muskeg, common dirt, straw, wood fibers, sawdust, cloth, fiberglass, wood chips, broken glass, concrete and brick fragments, shredded tires and metal as well as mixtures of various combinations of the above outlined fillers.
It is well known that structures exposed to the rays of the sun may absorb solar rays and rise above ambient temperature. For example, dark colored objects such as asphalt pavement as well as objects which are enclosed structures will rise above ambient temperature when exposed to the sun's energy. Other structures such as buildings may rise above ambient temperature due to activities within the building. In any case, infrared radiation from objects above ambient temperature may cause thaw-ing of the permafrost and consequent damage to the ecology and environ-ment of the area.

lV377~6 The present invention is particularly useful for application in areas where the ecology or environment may be damaged or hurt, as for instance, in the building of roads, pipelines, berms, runways for aircraft, ; tarmacs, building foundations or when it is necessary to remove or cut through hills or places where permafrost is present or in the placing of piling into permafrost. In fact, the invention is applicable in any place on permafrost where a structure or an installation or any type of construct-ion is required without thawing of the permafrost. It has been found that damage can be prevented to the ecology and/or environment by the addition of a reflective agent to the composition to thereby reflect the ultra-violet and infrared rays from the sun. The roadway, runway, tarmac or other structures coated with the composition of the invention do not absorb sufficient heat to melt the permafrost beneath it and thereby - prevent the ecological and environmental damage, which is now caused when the surface of the tundra is disturbed. It has been found that when the reflective agent is added to the resin composition and the composition used in construction or applied to an existing structure, roadbed, run-way, tarmac, or area of gravel, sand, or asphalt, the heat from the sun's rays is not absorbed and therefore the permafrost is not disturbed beneath or alongside of the test areas.
The composition of this invention when subjected to the heat-thaw cycle for a twenty-eight day test did not show signs of deteriorat-ion, discoloration, cracking or deformation in any way and it had the same strength as before being subjected to the heat-thaw cycle test.
When the reflective agent is used with the urethane composition, the deterioration effects of sunlight on the urethanes, paints, or asphalt or on any other substance where infrared rays cause damage and to which the composition can be applied is almost nullified.
When ultra-violet or infrared light is reflected from any surface ~-hich ha5 ~een treated with the reflective agent in the composit- ~-` 10377~6 ' ion, the surface appears white. Therefore runways, roadways, areas, build-ings or any structure painted or coated with the reflective agent in the composition would become illuminated at night through reflection. It is not necessary to treat the entire volume of composition used, only the surface layer need be treated unless the surface is subjected to very severe wear, in which case, the reflective agent should penetrate so as to allow for wear. When used in a paint, it should be incorporated throughout the volume or mixture. The quantity of the reflective agent to be used is relatively small. About one pound of the agent is sufficient to treat the composition necessary to cover an area of 200 - feet wide by 6,000 feet long at a thickness of about 1/4 to 1/2 an inch.
The ultra-violet and infrared rays are then totally reflected.
It has been further established that when the reflective agent was applied to an area of runway, the heat waves normally visible on a hot day are not present over the treated area and the area is cold to the touch. The untreated area is quite warm, in fact, the surface is soft because of the heat absorbed.
. .~
Temperature of course affects composition setting rate. The ;~ warmer the components are, say up to 125F, the faster they will set. It is therefore desirable in cold or subzero temperatures, to heat the oils being used to make the composition to thereby increase the setting rate.
The warm composition also has a tendency to increase the bond strength between a substrate and the composition.
Further details of this invention will be apparent from the following illustrative examples.
EXAMPLE I

PREPARATION OF A REPRESENTATIVE
POLYURETHANE PREPOLYMER

A polyurethane prepolymer is prepared by reacting tolylene di-cas 7Lor isocyanate ~60~20 type) ~ith a commercially available polymerized castor :

1~)37706 oil. The polymerized castor oil is obtained by methods known in the art and has an estimated molecular weight of approximately 1040, a hydroxyl number of about 151, isocyanate equivalent weight 346, acid value 11, density at 25C .0980 g./cm., viscosity at 25C is approxima~ely 3,000 centipoises. The prepolymer has a viscosity at 25C of 5 poises, a density at 25 of 9.2 lbs./gal., NCO content 13.7% and an equivalent weight per NCO
of 30.6.
EXAMPLE II

PREPARATION OF A REPRESENTATIVE OIL CATALYST
SYSTEM WITH A HEAT-REFLECTING AGENT
- ~
In this example, a commercially available amine catalyst for polyurethanes was used. It is essentially triethylene diamine. A 10 parts by weight portion of the triethylene diamine is thoroughly mixed with 120 parts by weight of a furfural extract of a petroleum rçfinery heavy catalytic cycle oil having the following properties: specific gravity (60F/60F) 1.07, boiling range 95-260C at 2 mm Hg, refractive index (20C) 1.64. From 5 to 10 parts of the heat-reflecting agent, 4,4'-bis-~3 phenylureido)-2,2' stilbenedisulfonic acid may be used.
It should be noted that in place of the petroleum fractions mentioned above there may be used instead a furfural extract of a heavy petroleum lube oil having the following properties: boiling range 187-208C at 10 mm Hg, specific gravity 1.04 (60F), refractive index (20C) 1.625. This oil is mainly aromatic.
EXAMPLE III

FORMATION OF AN OIL MODIFIED
POLYURETHANE COMPOSITION

Equal weights of the curing system-oil component and the poly-urethane prepolymer which were described above in Examples I and II, are mixed by hand for 30 seconds until a uniform mixture is obtained. The mix- -ture is applied by spraying to a strip of sand or other material which may

Claims (6)

THE EMBODIMENTS OF THE INVENTION IN WHICH AN EXCLUSIVE
PROPERTY OR PRIVILEGE IS CLAIMED ARE DEFINED AS FOLLOWS:

1. A method of insulating, stabilizing and protecting tundra and permafrost from thawing and unwanted subsidence which comprises applying to a surface a composition which includes about 10 to about 90% by weight of hydrocarbon oil, about 90 to about 10% by weight of polyurethane prepolymer, and a solar radiation reflecting agent, said composition being applied in sufficient amount to coat said surface which is either permafrost or a sub-strate on permafrost, and permitting said composition to harden, whereby said composition acts to reflect solar radiation from said surface, to prevent thawing of said permafrost.

2. A method according to claim 1 wherein said composition is applied to said surface by spraying in an amount sufficient to cover and penetrate to a desired depth.

3. A method according to claim 1 which further comprises initially forming said prepolymer by mixing a member selected from the group consisting of polyethers and polyesters with a polyisocyanate to form said prepolymer which is a polyurethane prepolymer.

4. A method according to claim 1 which comprises adding a catalyst for the prepolymer whereby the prepolymer cures in the composition after application to said surface to form a barrier film on or adjacent to the surface to which the composition is applied.

5. A composition for treating tundra and permafrost to reduce thawing and subsidence thereof comprising about 10 to about 90% by weight of a hydro-carbon oil, about 90 to about 10% by weight of a polyurethane prepolymer, a catalyst for said prepolymer and a solar energy reflecting agent.

6. A composition according to claim 5 wherein said reflecting agent is an infra-red reflecting agent.

be present on top of the permafrost at the rate of 7 gallons per 100 sq.
ft. A few minutes after application, dependent on the amount of catalyst and temperature of the oils used, the resin hardens the material which may be on top of the permafrost so that it can be used as a road for vehicles.
Most types of oils may be used for modifying the polyurethanes according to this invention. Most suitable are cheap crude oil, bunker oils and mixtures thereof. By-product oil, naturally produced, oils as for example from an oil well, may be used. All grades and gravities may be used, whether very heavy, low grade or higher gravity. The color of the oil is not critical since it is not necessary that the composition be transparent.