NATIONAL BUREAU OF STANDARDS REPORT

8607

AIR BLOWING ASPHALTS IN THE PRESENCE OFADDITIVE OILS, CATALYSTS AND POLYMERS

by

Sidney H. Greenfeld

NBS

U. S. DEPARTMENT OF COMMERCE

NATIONAL BUREAU OF STANDARDS

Lo°)B

The National Bureau of Standards is a principal focal point in the Federal Government for assuring

maximum application of the physical and engineering sciences to the advancement of technology in

industry and commerce. Its responsibilities include development and maintenance of the national stand-

ards of measurement, and the provisions of means for making measurements consistent with those

standards; determination of physical constants and properties of materials; development of methodsfor testing materials, mechanisms, and structures, and making such tests as may be necessary, particu-

larly for government agencies; cooperation in the establishment of standard practices for incorpora-

tion in codes and specifications; advisory service to government agencies on scientific and technical

problems; invention and development of devices to serve special needs of the Government; assistance

to industry, business, and consumers in the development and acceptance of commercial standards andsimplified trade practice recommendations; administration of programs in cooperation with United

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practice; and maintenance of a clearinghouse for the collection and dissemination of scientific, tech-

nical, and engineering information. The scope of the Bureau’s activities is suggested in the following

listing of its four Institutes and their organizational units.

Institute for Basic Standards. Electricity. Metrology. Heat. Radiation Physics. Mechanics. Ap-

plied Mathematics. Atomic Physics. Physical Chemistry. Laboratory Astrophysics.* Radio Stand-

ards Laboratory: Radio Standards Physics; Radio Standards Engineering.** Office of Standard Ref-

erence Data.

Institute for Materials Research. Analytical Chemistry. Polymers. Metallurgy. Inorganic Mate-

rials. Reactor Radiations. Cryogenics.** Office of Standard Reference Materials.

Central Radio Propagation Laboratory.** Ionosphere Research and Propagation. Troposphere

and Space Telecommunications. Radio Systems. Upper Atmosphere and Space Physics.

Institute for Applied Technology. Textiles and Apparel Technology Center. Building Research.

Industrial Equipment. Information Technology. Performance Test Development. Instrumentation.

Transport Systems. Office of Technical Services. Office of Weights and Measures. Office of Engineer-

ing Standards. Office of Industrial Services.

* NBS Group, Joint Institute for Laboratory Astrophysics at the University of Colorado.** Located at Boulder, Colorado.

NATIONAL BUREAU OF STANDARDS REPORT

NBS PROJECT NBS REPORT

421 .04-12-4210141 860715 December 1964

AIR BLOWING ASPHALTS IN THE PRESENCE OF

ADDITIVE OILS, CATALYSTS AND POLYMERS

by

Sidney Ho Greenfeld

Research AssociateAsphalt Roofing Industry Bureau

Organic Building Materials SectionBuilding Research Division

Institute for Applied Technology

Sponsored by

Asphalt Roofing Industry Bureau

IMPORTANT NOTICE

NATIONAL BUREAU OF S

for use within the Government,

and review. For this reason, t

whole or in part, is not auth

Bureau of Standards, Washint

the Report has been specificall

Approved for public release by the

Director of the National Institute of

Standards and Technology (NIST)

on October 9, 2015.

ess accounting documents intended

s subjected to additional evaluation

e listing of this Report, either in

he Office of the Director, National

ly the Government agency for which

copies for its own use.

II. $. DEPARTMENT OF COMMERCE

NATIONAL BUREAU OF STANDARDS

AIR BLOWING ASPHALTS IN THE PRESENCE OF

ADDITIVE OILS, CATALYSTS AND POLYMERS

Sidney H. Greenfeld

1 o INTRODUCTION

Bitumen has been used for many centuries in a wide variety of waterproofingapplications. For the first 5000 years of its use by man, it was appliedessentially as it came from nature. Bitumens from various sources weremore-or-less in demand because of their special properties. However, in

the second half of the nineteenth century, organized efforts were firstmade to modify bitumens by various processes and treatments and divorcethe dependence of their end uses from their sources.

a/In 1894 (1)~ ,

the first commercial process for the modification of

asphalt by air blowing was patented by F. X. Byerley. This patent describeda rather crude process for drawing air through petroleum residua to hardenthese residua. Although the process has been modified and improved manytimes, it still has its limitations for changing the properties of bitumens.In recent years, a number of publications have appeared which describe theeffect of various processing variables, such as air rate, temperature,agitation and still design, on the properties of blown asphalts (2). In

all instances the improvements in properties were limited by the compositionof the flux which was blown.

Asphalt producers have been concerned with these limitations and havetried numerous additives during the blowing process to produce asphaltswith desired properties. Amond the earlier modifying endeavors wasthe blending of crudes or residua to produce fluxes that would air-blowto the required specifications (3). Oils, called fluxing oils, and otherorganic products were added either before or after blowing to produceproducts with higher penetrations for a given softening point. Manyvarieties of inorganic and organic compounds have been used to makespecific adjustements in a given, asphalt (4, 5) . Abraham (4) reportsmany patents issued on these various treatments and Mertens and Greenfeld

(5) have shown that a given agent may be beneficial to asphalt from one

source and detrimental to asphalts from another.

a /

Numbers in parentheses refer to the references listed at the end of

this paper.

1

- 2 -

With all of the claims and counter claims in the patent literature andonly a few publications with substantiating data for the effects ofadditives during blowing on the properties of blown asphalts, it seemedthat further investigation of this phase was in order„ The effects ofa selected few representative additives on the blowing characteristicsof four fluxes and on the properties of the blown asphalts were studied.The fluxes were those the blowing characteristics of which have beenreported (2f).

2 . MATERIALS

The physical properties of the fluxes used in this program are tabulatedin Table 1. The California flux was supplied in one grade only; each of

the other three was supplied in two grades. The softer grade wasselected such that it could be blown to coating softening point-penetra-tion requirements without modification. The harder grade was selectedto require modification to meet this specification. In practice,, how-ever, the harder grades of these three fluxes could be blown to theserequirements under certain processing conditions without the use of

additives.

The California flux could not be obtained sufficiently soft to permitblowing to coating requirements. The limiting factor was the flashpoint; the crude was reduced to a flash point of 460°F (COC) to permitsafe handling. A discussion of the effects of processing variables on

this California flux and the soft fluxes from the other three sourceshas been published (2f)„

A number of materials were added to the asphalt fluxes prior to blowing.These materials are described in Table 2.

3. APPARATUS AND PROCEDURE

The apparatus used for blowing the asphalts and determining their dura-bilities are those described previously (2f). In the runs in which theflux-additive mixtures were blown without agitation, the additives weremixed with the fluxes externally with the aid of a laboratory stirrer.The mixtures were added to the stills at 300-350°F. In the runs in whichagitation was used, the additives were mixed with the fluxes in the stillswith the aid of the agitators. All fluxes were blown at 465~475°F, 0 or

1400 rpm agitation and 75 or 150 ft^/ton-min. air rate as reported.Initially the lower air rate had been arbitrarily selected, but because

* V.

‘

TABLE I.

ASPHALT FLUXES

FluxCalifornia

CoastalKansas

Soft HardTalco

Soft HardTia

Soft-i/

JuanaHard

Softening Point, °F 122 101 120 104 120 104 111

Penetration at 32°FS

0 . 1 mm 20 42 18 44 27 44 25

Penetration at 77CF, 0 . 1 mm 64 249 80 190 92 152 91

Penetration at 115°F,0*1 mm TS TS TS TS TS 222 232

Specific Gravity at 77°F 1 .030 0.994 1.004 1.020 1.022 1 .004 1.011Flash Point (C.O.C.)

,

° F 460 635 645 555 560 575 620Asphaltenes, °L 30 .7 19.3 24.9 26.7 28.1 23.4 20.8

Sulfur, 70 5*6 1.4 1.4 4.6 4.8 2.9 3.1

— Partially blown

2 /—' Too Soft

i,

.

tv[.

.

TABLE 2 . ADDITIVES

I

II

OILS

MaterialFlash Point

(COE) °

F

Viscosityat 2 10° F SSU

Pour Point,°F

Mid Continent Bright Stock 600 160 5

Western Bright Stock 615 196 10

Western Reclaimed Lube Oil 440 68 -

Eastern Reclaimed Lube Oil 460 61 -

"CATALYSTS"

Material Form Manufacturer Designation

Ferric Chloride Hexahydrate Baker 6c Adamson Company ReagentPhosphoric Acid 86% Solution Baker 6c Adamson Company ReagentPhytic AcidPyromellitic

707o Solution A. E. Staley Mfg . Co

.

ExperimentalDianhydride (PMDA)

Trimellitic AnhydrideWhite Powder E. I. duPont de Nemours 6c Co

.

SampleExperimental

(TMA)

VR-1 Acid 1 /

White PowderBrown Liquid

AmocoRohm

Chemicalsand Haas

Corp

.

Products

~ By-product of manufacture of sebacic acid from castor oil. Ratioof dibasic to monobasic acids = 1„2.

Polymer Form Manufacturer Manufacturer 1

sDesignation _ _ __

I

I

1

NeopreneSiliconeEpoxy

Polyvinyl FormalPolyvinyl Butral

Latex 6670 SolidsLiquid 6c Catalyst507, Epoxy Liquid50% Amide LiquidPowderPowder

E. I. duPont de Nemours & Co,

Dow-CorningDow Chemical CompanyGeneral Mills, Inc.

Shawinigan Resins Corp

.

Shawinigan Resins Corp.

LD-260RTV-521DER 332Versamid 140

Formyar 7/95SButvar 72A

3 -

some runs could not be completed in one day^, the higher rate was adoptedfor the later runs.

Softening points and penetrations (2f) were determined on each asphalt,

produced. The change in softening point was used to follow the progressof the blowing process; the penetrations were measured only on the

finished products.

All of the asphalts were exposed in two weatherometers^ two specimensof each in each machine. The figures reported are the averages of

these four specimens. In a few instances these replicates failedwidely apart; second sets of four specimens were exposed.

4. RESULTS

The blowing conditions and physical, properties of asphalts blown withoutadditives are summarized in Table 3. These results are used in compari-sons with the modified coatings and are compiled in Table 3 to demon-strate the variations in properties and durabilities that can be ex-

pected from variations In the flux and blowing conditions.

Tables 4,, 6 and 7 are summaries of the effects of fluxing oils^ cata-

lysts and polymers,, respectively,

on the physical properties of theblown asphalts. Table 8 contains the durability data on all three ofthese systems.

5. DISCUSSION

The roofing manufacturer and the asphalt refinerj,

to a lesser extents

are usually limited by economic considerations to a choice from a

relatively few asphalt fluxes. Occasionally normal processing of thesefluxes produces products of somewhat less-than-d'esired quality. Thequestion always arises concerning how the best qualities can be pro-duced within economic reason.

In 1957., it was reported that blown asphalts from a particular flux

decreased in durability as the softening point increased (6). In

1 964^ it was shown that by suitably changing one or more of the pro-cessing variables (temperature^ air rate or agitation ) }

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be blown to the same softening point with large variations in durabilityand production time and lesser variations in penetrations ( 2 f ) . Table 3

shows still another way of changing the softening point-penetrationrelation and the durabilities of asphalts. While not specifically designedas a part of this study,, this consideration is sufficiently important tothe discussion of the results to be considered before the discussion.It was found that asphalts blown from fluxes which came from the samebatch of crude, but reduced to different extents, were different both inphysical properties and in durability. As might be expected, the asphaltsproduced from the harder fluxes had lower penetrations than those producedfrom the corresponding softer fluxes blown under the same conditions.The blowing times in all but one instance were also shorter. However,despite the poorer properties, the asphalts produced from the harderfluxes were invariably, and in many cases appreciably, more durable—From these results it would seem that crude reduction to the greatestextent consistent with the production of a flux that can be blown tocoating-grade specifications is desirable for durability as well as flashpoint considerations.

Because of the flash point restrictions, the California flux could not

be supplied in a sufficiently soft grade to permit blowing to coatinggrade without modification. This point was discussed in. detail in

reference (2f) s Thus, reference California asphalts could not be producedwithin coating-grade specifications. Very few of the additives werecapable of modifying this flux sufficiently to permit the production of

specification coating-grade asphalts from it.

One of the most generally used and widely acceptable procedures usedto modify coating-grade asphalts is to dilute, or flux, the materialcharged to the blowing still with an oil. The oils used range fromreclaimed lubricating oil. through various refinery distillates to

heavy residual materials, which in themselves may be considered asphaltfluxes. It is quite difficult, to obtain what might be termed represen-tative materials because of the unlimited number available. Therefore,only a limited sampling of two of the more-common types of oil wereevaluated; two samples of each were used.

b/

There is some question concerning the exact processing of the TiaJuana Medium soft flux. It is believed that this material waspartially blown by the refinery.

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- 5

The two Bright Stock oils are high-viscosity-index distillate oils, one

from a Mid-Continent crude segregation and one from a California coastalsegregation, both of which are normally used as base materials with whichadditives are mixed to produce premium motor oils. They are paraffinicin nature; the aromatics, unsaturates and waxes have been largely removedthrough solvent extraction and dewaxing processes. Their name is

descriptive of their bright, clear appearance in contrast to the cloudy,

dark color of the straight distillate oils.

The eastern and western reclaimed lubricating oils are crank casedrainings, which have been filtered to remove sludge and solids and

topped to remove all light materials and water. They are dark in

color, almost as if they have finely divided, suspended carbon present.

The effects of the addition of 57o of each of these oils to each of the

hard fluxes before blowing are shown in Table 4. The blowing charac-teristics of the unmodified fluxes are reproduced for easy comparisonin this and the following tables. In order to provide a basis for

discussion and a plane of reference, the specification for a hypotheticalasphalt presented in reference (2 f ) is reproduced in Table 5. It shouldbe recalled that this specification is not one used by any one manufac-turer, but is one that tends to bracket, or include, a large number of

specifications in current use.

TABLE 5.

SPECIFICATION FOR A HYPOTHETICAL COATING-GRADE ASPHALT

'Property Range

Softening Point, °F 215-225Penetration at 32°F, 1/10 mm 10 minimumPenetration at 77°F, 1/10 mm 15-25

Penetration at 115°F, 1/10 mm 25-45

It is quite obvious from Table 4 that blown asphalts meeting this speci-fication were not produced from the California flux without modificationeither with or without agitation. The use of agitation, with a much-shorter residence time in the still, produced a product of considerablyimproved penetrations over the one produced without agitation, but still

short of the specification. None of the fluxing oils at the 5% level

- 6 -

was able to improve the penetrations sufficiently in the absence of

agitation to make the grade, but both the Eastern Reclaimed Lube Oiland Mid-Continent Bright Stock were close. However, neither of theseoils is available in areas in which this flux is used. A larger percen-tage of the western oils would have to be used to accomplish the same

effects

.

When agitation was used along with the fluxing oils, all except the

Mid-Continent Bright Stock increased the penetrations sufficientlyto meet the specification in Table 5. Despite the addition of theseoils, the blowing times were shorter in all of these runs than for the

unmodified flux.

The soft Kansas flux blew into grade whether or not agitation was used;the hard flux, only when agitation was used. However, without agitationthe coating-grade product failed to meet the specification by only one

penetration unit at 32°F. All of the modified fluxes produced specifi-cation products. Unlike the modified California fluxes, all but one of

the modified Kansas fluxes blew into grade more slowly than did thehard flux. (The run without agitation using Mid-Continent Bright Stockwas the exception). However, these runs were shorter than when the

soft flux was used alone. The high- temperature penetrations seemedto benefit least from the fluxing oils, and, in most instances, wereactually lower than the coating asphalt produced from the hard fluxwithout modification.

The reclaimed lubricating oils had almost no effect on the penetrationsof the asphalts produced from the Talco flux, but the Bright Stockschanged the high temperature penetrations. Without agitation, the

penetrations at 115°F were raised; with agitation, they were lowered.All of the fluxing oils increased the blowing times required to makecoating asphalts from the hard Talco flux.

The penetrations of the coating asphalts produced from 57. of each of

the fluxing oils in the hard Tia Juana flux were increased. This fluxproduced asphalts that were marginally acceptable without fluxing oilsand well within the specification range with them. The blowing timeswere increased appreciably in the absence of agitation, but onlyslightly when agitation was used.

- 7 -

From this discussion, it is quite obvious that the fluxing oils and basestocks must be carefully paired in order to improve the physical charac-teristics of the coating asphalt produced. While lowering of the pene-trations occurred only infrequent ly, many combinations produced littleimprovement and quite frequently the improvement was obtained at the

expense of an increase in blowing time.

The effects of these fluxing oils on the durabilities of coating asphaltswere also extremely variable. The largest improvements were manifestedby the western oils in the Talco asphalts blown without agitation. Thisflux produced asphalts with durabilities in the range of 32-56 days (2f)

under a wide variety of processing conditions, but with these fluxing oilsdurabilities of 85 days were obtained. Again, these western oils arenot normally available in areas in which Talco flux is processed, butthe Mid-Continent Bright Stock and similar oils are and produce comparableimprovements in durability.

The Western Bright Stock and Reclaimed Lubricating Oil and Mid-ContinentBright Stock also improved the California asphalts blown without agitation.These asphalts had durabilities comparable to the best California asphaltsproduced with agitation. However, these same oils were not beneficialwhen agitation was used.

When the Kansas flux was blown with 57, of each of the fluxing oils with-out agitation, there was marked improvement in each case over the

asphalt from the soft flux, but the asphalt produced with the EasternReclaimed Lubricating Oil was not as durable as the asphalt producedfrom the hard Kansas flux. When agitation was used, the EasternReclaimed Lube was definitely detrimental and, while the use of the

other fluxing oils produced asphalts more durable than the one fromthe soft flux, none was as durable as the asphalt produced from the

hard flux. Thus, for the Kansas flux, processing changes seemed to

accomplish more than the fluxing oils.

The effects of these four fluxing oils on the durabilities of the TiaJuana asphalts were less than the effects of processing to the harderf lux.

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The results presented above corroborate in more detail those reportedby Mertens and Greenfeld (5) and stress the importance of matchingthe fluxing oil to the flux with which it is to be used.

Certain materials when added to fluxes in small concentrations beforeblowing produce large changes in the blown asphalts. These materialshave come to be known as catalysts,, even though they are, in manycases, consumed in the reaction. Abraham (7) lists large numbers of

these for accelerating the blowing reaction, increasing or decreasingthe penetrations, increasing the ductility and improving the weatheringcharacteristics of the blown asphalts. A few of these many types of

materials haA/e been investigated.

Ferric chloride, typical of the Lewis Acids, has been used for manyyears to accelerate blowing, increase penetrations and improve the

fire tests of the finished products. While its advantages are many,it has two inherent deficiencies, which have seemed to limit itsuse. Ferric chloride tends to accelerate photooxidation (8) andasphalts containing ferric chloride have been reported to be corrosiveunder some circumstances (9)

.

In this study, the four fluxes were each blown with 1% ferric chlorideboth with and without agitation. The effects on blowing time wereamazing (Table 6). The air rate of 150 ft^/TM could not be used withthe California flux because the reaction was too rapid; thus, the airrate was halved and the blowing time was still reduced to 20~257o ofnormal. The penetrations were increased appreciably, but the low-

temperature penetrations were not raised enough to meet the specifica-tion.

Ferric chloride (1%) also accelerated the blowing of the fluxes fromthe other three sources. Kansas flux with 1% ferric chloride blew to

2i9°F softening point in 4 minutes with, and 19 minutes without, agita-tion instead of 62 and 202 minutes, respectively. The Talco and TiaJuana fluxes responded similarly, but to different degrees. The pene-trations at ail three temperatures were increased for the Kansas,Talco and Tia. Juana asphalts. The asphalts made from the Kansas and

Tia Juana fluxes actually had penetrations exceeding the specificationmax ima

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The effects of the ferric chloride on durability were not uniform

.

Appreciable improvement was observed only in the case of Tia Juanaasphalt blown without agitation. Kansas asphalt blown with agitation,on the other hand, had its durability seriously impaired.

Campbell and Wright (8) presented evidence to show that ferric chloridemight be an oxidation inhibitor in the absence of light and an oxidationpromoter in its presence. It appeared that the rapid increase in

softening point during blowing is the result of other than reactionsin which oxygen is taken into the molecules in asphalt. They describealkylation and polymerization reactions which can account for the in-

creases in softening point without the addition of oxygen. The other,and generally conceded most important, reaction during blowing is

condensation, or dehydrogenation, which may account for the largequantities of water formed during blowing. All of these reactionscan be accelerated by ferric chloride, but the latter also requiresoxygen. This may partially explain why despite the fact that littleoxygen remains in the blown asphalt, blowing with nitrogen requiresa much longer time than blowing with air.

Based on a paper by Goppel and Knotnerus (10), an appreciable amountof ester formation occurred during blowing, especially at the lowerblowing temperatures. Recently this conclusion was challenged byCampbell and Wright (11) because they were unable to find reinforce-ment of the carbonyl absorbance at 1700 cm" 1

' by the addition of modelester compounds to asphalts. Whether or not ester formation occursto any appreciable degree, certain acids and anhydrides added toasphalt fluxes before blowing modify the blown asphalt. A numberof these materials will be discussed.

Phosphoric acid, or phosphorus pentoxide, has been used for manyyears to modify asphalts; a number of patents have been issued on

its use (7) and a number of articles have been published (12).

Phosphoric acid is probably not a catalyst (12a), but enters intothe reaction and cannot be extracted from the asphalt with water (12a).

As long as there was uncombined phosphoric acid or anhydride present,the reaction rate was higher than normal; when it was exhausted, the

reaction rate dropped appreciably. When concentrations lower than

one percent were used, this deceleration was always observed before

10

the coating-grade softening point was attained; at the one percent level

the point of exhaustion was not reached with all fluxes. Thus, someof the runs show an appreciable shortening in blowing time while othersshow an actual increase. The California asphalt was improved by the useof one percent phosphoric acid. The penetrations were raised into thespecification ranges and the blowing times were reduced about 40%. Thedurabilities were increased between 30 and 80%,. The penetrations of

all of the other asphalts were also increased, but not as spectacularlyas in the case of the California asphalt. The blowing times of Kansasand Tia Juana fluxes were reduced when agitation was used, but not in

the absence of agitation. The blowing times of the Talco flux wereincreased. The durabilities of the Kansas asphalts were increased, but

those of the Talco and Tia Juana asphalts, not affected. Thus, whilephosphoric acid always increased the penetrations of blown asphalts, it

had mixed effects on their blowing times and durabilities.

Phytic acid, the hexaphosphor ic acid ester of inositol, offers manymore reaction sites per molecule than does phosphoric acid. If esterformation were the route by which asphalt hardening occurred, thismaterial with its twelve reactive sites could conceivably become the

nucleus of large molecules. However, in practice it reacted very muchlike phosphoric acid at the same weight concentration. The increasesin penetrations were about the same; as were the blowing times. However,in all but the Talco asphalts blown with agitation, the durabilityincrease was greater for the asphalts produced with phytic acid. Theimprovements ranged from an insignificant single day to 16 days.

Polyfunctional carboxylic acids and anhydrides are readily availableand more like the acids that would be formed by the oxidation of hydro-carbons. While many carboxylic acids are notoriously heat sensitive,some remain stable for periods of time under the conditions of blowing.The pyromellitic dianhydride is tetrafunctional, the trimellitic anhydrideis trifunctional and the VR- 1 acids larely difunctional. All of theseacids could form polyester type polymers with alcohols either present in

the flux or generated during blowing. These acids and anhydrides did not

produce the same effects on all four fluxes. There was no trend in anyasphalt related to the number of carboxyl groups per molecule. However,for three of the four fluxes, one percent of any of these compoundstended to raise the penetrations of the blown asphalts. Talco asphaltstended to have reduced penetrations. Similarly, the blowing times wereusually, but not always, decreased by these additives. In extreme in-

stances, the blowing time was halved.

These carboxylic acids and anhydrides also produced mixed effects on thedurabilities of the asphalts. These ranged from an increase to 100 daysfor the durability of the Tia Juana asphalt blown with TMA withoug agita-tion to a decrease to 60 days of the Kansas asphalt blown with TMA withagitation. TMA was the most effective additive for improving the dura-bility of the Tia Juana asphalt; phytic acid was next most effective.Phytic acid was also most effective at the one percent level for im-

proving the durabilities of the California and Kansas asphalts. Whilenone of these materials improved the durability of the Talco asphaltsblown with agitation, the phytic acid and the carboxylic additives im-

proved the durabilities of the Talco asphalts blown without agitation.

In recent years an effort has been made to modify asphalt through the

addition of polymers. Asphalt- and coal tar-epoxy coatings are on the

market. Various elastomers have been mixed with asphalt for paving (13)

and laminating uses. Mertens and Greenfeld (5) reported on the effectsof a hydrocarbon polymer on the durability of asphalts.

Polymers added to the extent of 57. of the asphalt produced varied, butnot large, changes in the penetrations (Table 7). The only polymerthat changed the penetrations of the California asphalt sufficientlyto bring it "into grade" was Saran. Saran also improved the suscep-tibility appreciably, but it simultaneously dropped the durability from62 to 37 days. The epoxy resin improved the durability of the Californiaasphalt to 77 days even though it did not raise the penetrations suffi-ciently to meet the specification. Poly(vinyl formal) and poly (vinyl

butral) had no effect on the penetrations, but. increased the durabilitiesof the California asphalts to 96 and 100 days, respectively.

None of the three polymers used improved the penetrations of the Kansasasphalt more than two units; all of them actually decreased the hightemperature penetration. Simularly, none of them, increased the dura-bilities; the Silicone reduced the durability by more than 507>. It

was obvious that the Silicone did not react with the asphalt, for it

appeared throughout the asphalt as a white powder. The variations in

durability among the individual specimens were very large.

All of the polymers decreased the penetrations of the Talco asphaltsfrom two to nine units. The effect on durability was small except for

that of the poly(vinyl butral) ; it increased the durability by 23

percent

.

EFFECT

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ON

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PROPERTIES

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TABLE 8 . EFFECT OF ADDITIVES ON DURABILITY

DURAB XLITY (5 l-9c ) , DAYS

Asphalt California Kansas Talco Tia JuanaBlowing Conditions AB AB A BAB

Additive

FLUXING OILS

Alone (Hard) 45 62 81 100 57 62 6861I

5^//Ll

5 5—

59^

80

+ 5% ERL 38 40 73 58 72 41 65

+ 5°L WRL 63 58 S3 84 86 55 68

+ 57o MCBS 58 41 87 91 76 83 72

+ 5% WBS 59 47 S3 87 84 63 67

Alone (Soft) - - 65 81 56 47 50

"CATALYSTS If

Alone (Hard)

+ 1% FeCl 3

45i/

54-62

54

81

62

100

64

57

61

62

58

68

85T71I

80

68

+ 1% H3PO4 841 /89“

81 9 7 1062 /

63 60 82

+ 17o Phytic Acid 85 110 10 72

S5f60=-'

72 59 85t86— 7

98

+ 1% FMDA = 53 - 74 48 694- 17. TMA 77 70 77 74 62 100 74

+ 17o ¥R~ 1 76 60 - - 73 47 8259-

73

Alone (Soft) = - 65 81 56 47 50

POLYMERS

Alone (Hard) 45 622 /

V.H2

3 ?i/

34i/

ioof',

S 61 '

81 100 57 62 68 804- 57c Epoxy 77 87 - 46 - 63 -

4- 57o Neoprene 45 82 - 64 - Curdles -

+ 57o Saran = - - - - - -

+ 57c Silicone 48 34 - 51 - 57 -

4- 57o Vinyl Butral - - - 70 - - -

+ 57c Vinyl Formal - - - - -

59- /

-

Alone (Soft.) = 65 81 56 47 50

Blowing Conditions . A =

B =475 °F,

475°F,0 r .p „nu

1400 r.p,

150

.m.

,

ft^/Ton Min.75 ft 3 /Ton Min.

- 12 -

The Neoprene latex curdled, when added to the Tia Juana asphalt at a

number of different temperatures, even though no difficulty was en-countered mixing it with the other three asphalts. The epoxy resinreduced the penetrations of Tia Juana asphalt while Silicone increasedthem.. Both reduced the durability slightly.

As reported by Martens and Greenfeld (5) for a hydrocarbon polymer in

asphalts, the effects of these polymers on the asphalts were quiteirregular. Each asphalt“polymer system must be evaluated on its ownmerits

.

6. SUMMARY AND CONCLUSIONS

The properties of blown asphalts can be modified by the addition ofsmall quantities of fluxing oils, catalysts or polymers to their fluxesbefore blowing. The effects are not uniformly the same, but varywith both the source of the flux and the processing. Deleterious as

well as beneficial results can be obtained; it is critically importantto evaluate each flux-additive system on its own merits.

The improvements in durability produced by processing reported earlier(2 f ) were extended by the use of additives. The most durable productsproduced from each flux with additives were”

Concen- Blowing DurabilityFlux Additive tration Conditions (51-9C)

Days

California Poly (vinyl butral) 5 B 100

California Poly (vinyl formal) 5 B 96

Kansas Phytic acid 1 A 110

Kansas Phytic acid 1 B 107

Talco Western Reclaimed Lube 5 A 86

Ta 1co Western Bright Stock 5 A 84Talco Mid“Cont„ Bright Stock 5 B 83Tia Juana Trimellitic anhydride 1 A 100

A = 475°F, 0 r.p.m., 150 ft^/Ton-Min.B = 475 a

F, 1400 r,p.i. ; 75 ft^/Ton-Min.

13

7. REFERENCES

(1) Uo S» Patent 524,130 to F» X. Byerley, August 7 ,1894.

(2) (a) Rescorla, A. R., W, E„ Forney, A. F„ Blakey and M. J. Frino,Ind. Eng. Chem. 48, 378 (1956).

(b) Gun,, R. B„ and I. L. Gurevich, Novosti Neftyanoi. Tekh.,Neftepererabotka 1 958 , No. 5 ,

15-17.

(c) Che Iton, A. M,;

R. N. Traxler and J, W, Romberg, Xnd. Eng.

Chem. 5U 1353 (1959),..

(d) Muraya, K., T, Fukushima, Y. Fukuda, and A. Shimada, Bull.

Jap. Pet. Inst. 2 f 63 (1960).

(e) Zakar, P. and Mozes, G„, Erdol u Kohle 14 , 812 (1961).

(f) Greenfeld, S, H., Ind. Eng. Chem. P. R. & D, 3, 158 (1964).

(3) U. S, Patent 1,385,511 to H. R. Wardell, July 26, 1921 for example.

(4) Abraham,, H„ . Asphalts & Allied. Substances II , 166-172, D. VanNostrand & Co. , 1961.

(5) Mertens, E. W, and S. H, Greenfeld, Some Qualitative Effects of

Composition and Processing on Weatherability of Coating-GradeAsphalts, ASTM STP 280, 20=29 (I960).

(6) Greenfeld, S. H., NBS Building Materials and Structures Report

147, 6 (1957).

(7) Abraham, H., Asphalts & Allied Substances II , 168-172, D. VanNostrand & Go., 1961.

(8) Campbell, P» G. and J. R. Wright, Ind. Eng. Chem. Prod. Res.

Dev. 3>, 186 (1964).

(9) Private communication from G, W. Clarvoe.

(10)

Goppel, J. M'., and J. Knotnerus, Fourth World Pet. Cong. Proc,,

Sect. Ill/G, 399 (1955).

14

(11) Campbell, P. G. and J. R. Wright, J. Res. NBS 68C, 115 (1964).

(12) (a) Shearon, W. H., Jr. and A. J. Hoiberg, Ind. Eng. Chem. 45 ,

2122 (1953).

(b) Eng, J., G, W. Govier and D. Quon, Can. J. Technol. 33 ,

360-77 (1955).

(13) Endres, H, A. and W. W. Burr, U. S. Patent 3,127,367, March 31,

1964.

8. ACKNOWLEDGMENT

This work was sponsored by the Asphalt Roofing Industry Bureau at the

National Bureau of Standards. The author gratefully acknowledges the

guidance of the ARIB Research Committee, which performed as a steeringcommittee for this project, and the help of J. C. Weeks and T, R. Davisin collecting the data.

USCOMM-NBS-DC