NATIONAL BUREAU OF STANDARDS REPORT

8607

AIR BLOWING ASPHALTS IN THE PRESENCE OF

ADDITIVE 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 methods

for testing materials, mechanisms, and structures, and making such tests as may be necessary, particularly for government agencies; cooperation in the establishment of standard practices for incorporation 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 and

simplified trade practice recommendations; administration of programs in cooperation with United

States business groups and standards organizations for the development of international standards of practice; and maintenance of a clearinghouse for the collection and dissemination of scientific, technical, 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. Applied Mathematics. Atomic Physics. Physical Chemistry. Laboratory Astrophysics.* Radio Standards Laboratory: Radio Standards Physics; Radio Standards Engineering.** Office of Standard Ref- erence Data. Institute for Materials Research. Analytical Chemistry. Polymers. Metallurgy. Inorganic Materials. 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.

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* 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 8607

15 December 1964

AIR BLOWING ASPHALTS IN THE PRESENCE OF

ADDITIVE OILS, CATALYSTS AND POLYMERS

by

Sidney Ho Greenfeld

Research Associate

Asphalt Roofing Industry Bureau

Organic Building Materials Section

Building 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 waterproofing

applications. For the first 5000 years of its use by man, it was applied

essentially as it came from nature. Bitumens from various sources were more-or-less in demand because of their special properties. However, in

the second half of the nineteenth century, organized efforts were first

made to modify bitumens by various processes and treatments and divorce

the 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 described

a rather crude process for drawing air through petroleum residua to harden

these residua. Although the process has been modified and improved many

times, it still has its limitations for changing the properties of bitumens.

In recent years, a number of publications have appeared which describe the

effect 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 composition

of the flux which was blown.

Asphalt producers have been concerned with these limitations and have

tried numerous additives during the blowing process to produce asphalts

with desired properties. Amond the earlier modifying endeavors was

the blending of crudes or residua to produce fluxes that would air-blow

to the required specifications (3). Oils, called fluxing oils, and other

organic products were added either before or after blowing to produce

products with higher penetrations for a given softening point. Many

varieties of inorganic and organic compounds have been used to make

specific adjustements in a given, asphalt (4, 5) . Abraham (4) reports

many 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 and

only a few publications with substantiating data for the effects of

additives during blowing on the properties of blown asphalts, it seemed

that further investigation of this phase was in order„ The effects of

a selected few representative additives on the blowing characteristics

of four fluxes and on the properties of the blown asphalts were studied.

The fluxes were those the blowing characteristics of which have been

reported (2f).

2 . MATERIALS

The physical properties of the fluxes used in this program are tabulated

in Table 1. The California flux was supplied in one grade only; each of

the other three was supplied in two grades. The softer grade was selected such that it could be blown to coating softening point-penetration requirements without modification. The harder grade was selected

to require modification to meet this specification. In practice,, however, the harder grades of these three fluxes could be blown to these

requirements under certain processing conditions without the use of

additives.

The California flux could not be obtained sufficiently soft to permit

blowing to coating requirements. The limiting factor was the flash

point; the crude was reduced to a flash point of 460°F (COC) to permit

safe handling. A discussion of the effects of processing variables on this California flux and the soft fluxes from the other three sources

has 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 durabilities are those described previously (2f). In the runs in which the

flux-additive mixtures were blown without agitation, the additives were mixed 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 which

agitation was used, the additives were mixed with the fluxes in the stills

with 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

Flux

California

Coastal

Kansas

Soft Hard

Talco

Soft Hard

Tia

Soft-i/

Juana

Hard

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

Penetration at 32°F S 0 . 1 mm 20 42 18 44 27 44 25

Penetration at 77 C F, 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 1.011

Flash Point (C.O.C.) , ° F 460 635 645 555 560 575 620

Asphaltenes, °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

Material Flash Point

(COE) °

F

Viscosity

at 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 Reagent

Phosphoric Acid 86% Solution Baker 6c Adamson Company Reagent

Phytic Acid

Pyromellitic

707o Solution A. E. Staley Mfg . Co

.

Experimental

Dianhydride (PMDA)

Trimellitic Anhydride

White Powder E. I. duPont de Nemours 6c Co

.

Sample

Experimental

(TMA)

VR-1 Acid 1 / White Powder

Brown Liquid

Amoco

Rohm

Chemicals

and Haas

Corp

.

Products

~ By-product of manufacture of sebacic acid from castor oil. Ratio

of dibasic to monobasic acids = 1„2.

Polymer Form Manufacturer Manufacturer 1 s Designation _ _ __

I

I

1

Neoprene

Silicone

Epoxy

Polyvinyl Formal

Polyvinyl Butral

Latex 6670 Solids

Liquid 6c Catalyst

507, Epoxy Liquid

50% Amide Liquid

Powder

Powder

E. I. duPont de Nemours & Co,

Dow-Corning

Dow Chemical Company

General Mills, Inc.

Shawinigan Resins Corp

.

Shawinigan Resins Corp.

LD-260

RTV-521

DER 332

Versamid 140

Formyar 7/95S

Butvar 72A

3

-

some runs could not be completed in one day^, the higher rate was adopted

for the later runs.

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

produced. The change in softening point was used to follow the progress

of the blowing process; the penetrations were measured only on the

finished products.

All of the asphalts were exposed in two weatherometers^ two specimens

of each in each machine. The figures reported are the averages of

these four specimens. In a few instances these replicates failed

widely apart; second sets of four specimens were exposed.

4. RESULTS

The blowing conditions and physical, properties of asphalts blown without

additives are summarized in Table 3. These results are used in comparisons with the modified coatings and are compiled in Table 3 to demonstrate 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^ catalysts and polymers,, respectively, on the physical properties of the

blown asphalts. Table 8 contains the durability data on all three of

these systems.

5. DISCUSSION

The roofing manufacturer and the asphalt refiner j, to a lesser extent s are usually limited by economic considerations to a choice from a relatively few asphalt fluxes. Occasionally normal processing of these

fluxes produces products of somewhat less-than-d'esired quality. The

question always arises concerning how the best qualities can be produced 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 processing variables ( temper ature^ air rate or agitation) } asphalts could
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be blown to the same softening point with large variations in durability

and production time and lesser variations in penetrations ( 2 f ) . Table 3 shows still another way of changing the softening point-penetration

relation and the durabilities of asphalts. While not specifically designed

as a part of this study,, this consideration is sufficiently important to

the discussion of the results to be considered before the discussion.

It was found that asphalts blown from fluxes which came from the same batch of crude, but reduced to different extents, were different both in

physical properties and in durability. As might be expected, the asphalts

produced from the harder fluxes had lower penetrations than those produced

from 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 harder

fluxes were invariably, and in many cases appreciably, more durable—

From these results it would seem that crude reduction to the greatest

extent consistent with the production of a flux that can be blown to

coating-grade specifications is desirable for durability as well as flash

point considerations.

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

be supplied in a sufficiently soft grade to permit blowing to coating

grade without modification. This point was discussed in. detail in

reference (2f) s Thus, reference California asphalts could not be produced

within coating-grade specifications. Very few of the additives were

capable 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 used

to modify coating-grade asphalts is to dilute, or flux, the material

charged to the blowing still with an oil. The oils used range from

reclaimed lubricating oil. through various refinery distillates to

heavy residual materials, which in themselves may be considered asphalt

fluxes. It is quite difficult, to obtain what might be termed representative materials because of the unlimited number available. Therefore,

only a limited sampling of two of the more-common types of oil were

evaluated; two samples of each were used.

b/

There is some question concerning the exact processing of the Tia

Juana Medium soft flux. It is believed that this material was partially 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 coastal

segregation, both of which are normally used as base materials with which

additives are mixed to produce premium motor oils. They are paraffinic

in nature; the aromatics, unsaturates and waxes have been largely removed

through 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 case drainings, 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 characteristics of the unmodified fluxes are reproduced for easy comparison

in this and the following tables. In order to provide a basis for

discussion and a plane of reference, the specification for a hypothetical

asphalt presented in reference (2 f ) is reproduced in Table 5. It should

be recalled that this specification is not one used by any one manufacturer, 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 215-225

Penetration at 32°F, 1/10 mm 10 minimum

Penetration 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 specification were not produced from the California flux without modification

either with or without agitation. The use of agitation, with a muchshorter residence time in the still, produced a product of considerably

improved 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 Oil

and Mid-Continent Bright Stock were close. However, neither of these

oils is available in areas in which this flux is used. A larger percentage 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 sufficiently

to meet the specification in Table 5. Despite the addition of these

oils, 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 agitation

the coating-grade product failed to meet the specification by only one penetration unit at 32°F. All of the modified fluxes produced specification products. Unlike the modified California fluxes, all but one of

the modified Kansas fluxes blew into grade more slowly than did the

hard flux. (The run without agitation using Mid-Continent Bright Stock

was the exception). However, these runs were shorter than when the

soft flux was used alone. The high- temperature penetrations seemed

to benefit least from the fluxing oils, and, in most instances, were actually lower than the coating asphalt produced from the hard flux

without modification.

The reclaimed lubricating oils had almost no effect on the penetrations

of the asphalts produced from the Talco flux, but the Bright Stocks

changed 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 make

coating 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 flux

produced asphalts that were marginally acceptable without fluxing oils

and well within the specification range with them. The blowing times were increased appreciably in the absence of agitation, but only

slightly when agitation was used.

- 7

-

From this discussion, it is quite obvious that the fluxing oils and base

stocks must be carefully paired in order to improve the physical characteristics of the coating asphalt produced. While lowering of the penetrations occurred only infrequent ly, many combinations produced little

improvement 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 asphalts were also extremely variable. The largest improvements were manifested

by the western oils in the Talco asphalts blown without agitation. This

flux produced asphalts with durabilities in the range of 32-56 days (2f)

under a wide variety of processing conditions, but with these fluxing oils

durabilities of 85 days were obtained. Again, these western oils are not normally available in areas in which Talco flux is processed, but

the Mid-Continent Bright Stock and similar oils are and produce comparable

improvements in durability.

The Western Bright Stock and Reclaimed Lubricating Oil and Mid-Continent

Bright Stock also improved the California asphalts blown without agitation.

These asphalts had durabilities comparable to the best California asphalts

produced with agitation. However, these same oils were not beneficial

when agitation was used.

When the Kansas flux was blown with 57, of each of the fluxing oils without agitation, there was marked improvement in each case over the

asphalt from the soft flux, but the asphalt produced with the Eastern

Reclaimed Lubricating Oil was not as durable as the asphalt produced

from the hard Kansas flux. When agitation was used, the Eastern

Reclaimed Lube was definitely detrimental and, while the use of the

other fluxing oils produced asphalts more durable than the one from

the 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 Tia

Juana asphalts were less than the effects of processing to the harder

f lux.

I

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- 8 -

The results presented above corroborate in more detail those reported

by Mertens and Greenfeld (5) and stress the importance of matching

the fluxing oil to the flux with which it is to be used.

Certain materials when added to fluxes in small concentrations before

blowing produce large changes in the blown asphalts. These materials

have come to be known as catalysts,, even though they are, in many

cases, consumed in the reaction. Abraham (7) lists large numbers of

these for accelerating the blowing reaction, increasing or decreasing

the penetrations, increasing the ductility and improving the weathering

characteristics 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 many

years 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 its use. Ferric chloride tends to accelerate photooxidation (8) and

asphalts containing ferric chloride have been reported to be corrosive

under some circumstances (9)

In this study, the four fluxes were each blown with 1% ferric chloride

both with and without agitation. The effects on blowing time were amazing (Table 6). The air rate of 150 ft^/TM could not be used with

the California flux because the reaction was too rapid; thus, the air

rate was halved and the blowing time was still reduced to 20~257o of

normal. The penetrations were increased appreciably, but the lowtemperature penetrations were not raised enough to meet the specification.

Ferric chloride (1%) also accelerated the blowing of the fluxes from

the other three sources. Kansas flux with 1% ferric chloride blew to

2i9°F softening point in 4 minutes with, and 19 minutes without, agitation instead of 62 and 202 minutes, respectively. The Talco and Tia

Juana fluxes responded similarly, but to different degrees. The penetrations 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 specification

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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 Juana

asphalt 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 chloride

might be an oxidation inhibitor in the absence of light and an oxidation

promoter in its presence. It appeared that the rapid increase in

softening point during blowing is the result of other than reactions

in which oxygen is taken into the molecules in asphalt. They describe

alkylation 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 large

quantities of water formed during blowing. All of these reactions

can be accelerated by ferric chloride, but the latter also requires

oxygen. This may partially explain why despite the fact that little

oxygen remains in the blown asphalt, blowing with nitrogen requires

a much longer time than blowing with air.

Based on a paper by Goppel and Knotnerus (10), an appreciable amount

of ester formation occurred during blowing, especially at the lower

blowing temperatures. Recently this conclusion was challenged by

Campbell and Wright (11) because they were unable to find reinforcement of the carbonyl absorbance at 1700 cm" 1

' by the addition of model

ester compounds to asphalts. Whether or not ester formation occurs

to any appreciable degree, certain acids and anhydrides added to

asphalt fluxes before blowing modify the blown asphalt. A number

of these materials will be discussed.

Phosphoric acid, or phosphorus pentoxide, has been used for many

years 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 into

the 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, some

of the runs show an appreciable shortening in blowing time while others

show an actual increase. The California asphalt was improved by the use

of one percent phosphoric acid. The penetrations were raised into the

specification ranges and the blowing times were reduced about 40%. The

durabilities were increased between 30 and 80%,. The penetrations of

all of the other asphalts were also increased, but not as spectacularly

as in the case of the California asphalt. The blowing times of Kansas

and Tia Juana fluxes were reduced when agitation was used, but not in

the absence of agitation. The blowing times of the Talco flux were

increased. The durabilities of the Kansas asphalts were increased, but

those of the Talco and Tia Juana asphalts, not affected. Thus, while

phosphoric 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 many

more reaction sites per molecule than does phosphoric acid. If ester

formation were the route by which asphalt hardening occurred, this

material with its twelve reactive sites could conceivably become the

nucleus of large molecules. However, in practice it reacted very much

like phosphoric acid at the same weight concentration. The increases

in penetrations were about the same; as were the blowing times. However,

in all but the Talco asphalts blown with agitation, the durability

increase was greater for the asphalts produced with phytic acid. The

improvements ranged from an insignificant single day to 16 days.

Polyfunctional carboxylic acids and anhydrides are readily available

and more like the acids that would be formed by the oxidation of hydrocarbons. 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 anhydride

is trifunctional and the VR- 1 acids larely difunctional. All of these

acids 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 any

asphalt related to the number of carboxyl groups per molecule. However,

for three of the four fluxes, one percent of any of these compounds

tended to raise the penetrations of the blown asphalts. Talco asphalts

tended to have reduced penetrations. Similarly, the blowing times were

usually, but not always, decreased by these additives. In extreme instances, the blowing time was halved.

These carboxylic acids and anhydrides also produced mixed effects on the

durabilities of the asphalts. These ranged from an increase to 100 days

for the durability of the Tia Juana asphalt blown with TMA withoug agitation to a decrease to 60 days of the Kansas asphalt blown with TMA with

agitation. TMA was the most effective additive for improving the durability of the Tia Juana asphalt; phytic acid was next most effective.

Phytic acid was also most effective at the one percent level for improving the durabilities of the California and Kansas asphalts. While

none of these materials improved the durability of the Talco asphalts

blown with agitation, the phytic acid and the carboxylic additives improved 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 effects

of a hydrocarbon polymer on the durability of asphalts.

Polymers added to the extent of 57. of the asphalt produced varied, but

not large, changes in the penetrations (Table 7). The only polymer

that changed the penetrations of the California asphalt sufficiently

to bring it "into grade" was Saran. Saran also improved the susceptibility appreciably, but it simultaneously dropped the durability from

62 to 37 days. The epoxy resin improved the durability of the California

asphalt to 77 days even though it did not raise the penetrations sufficiently to meet the specification. Poly(vinyl formal) and poly (vinyl

butral) had no effect on the penetrations, but. increased the durabilities

of the California asphalts to 96 and 100 days, respectively.

None of the three polymers used improved the penetrations of the Kansas

asphalt more than two units; all of them actually decreased the high

temperature penetration. Simularly, none of them, increased the durabilities; 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 asphalts

from two to nine units. The effect on durability was small except for

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

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EFFECT

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TABLE 8 . EFFECT OF ADDITIVES ON DURABILITY

DURAB XLITY (5 l-9c ) , DAYS

Asphalt California Kansas Talco Tia Juana

Blowing

Additive

Conditions AB AB A BAB

FLUXING OILS

Alone (Hard) 45 62 81 100 57 62 68

61I

5^//L

l

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

45 i/ 54-

62

54

81

62

100

64

57

61

62

58

68

85T

71I

80

68 + 1% H3PO4

84

1 / 89“

81 9 7 106

2 / 63 60 82 + 17o Phytic Acid 85 110 10 7 2 S5f

60=-'

72 59 85t 86—7 98 + 1% FMDA = 53 - 74 48 69

4- 17. TMA 77 70 77 74 62 100 74

+ 17o ¥R~ 1 76 60 - - 73 47 82

59-

73

Alone (Soft) = - 65 81 56 47 50

POLYMERS

Alone (Hard) 45 62

2 / V.H

2 3 ?i/

34i/

ioof',

S 61'

81 100 57 62 68 80

4- 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 resin

reduced the penetrations of Tia Juana asphalt while Silicone increased

them.. 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 quite

irregular. Each asphalt “polymer system must be evaluated on its own merits

.

6. SUMMARY AND CONCLUSIONS

The properties of blown asphalts can be modified by the addition of

small quantities of fluxing oils, catalysts or polymers to their fluxes

before blowing. The effects are not uniformly the same, but vary

with both the source of the flux and the processing. Deleterious as well as beneficial results can be obtained; it is critically important

to 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 products

produced from each flux with additives were”

Concen- Blowing Durability

Flux 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 1 co Western Bright Stock 5 A 84

Talco Mid“Cont„ Bright Stock 5 B 83

Tia 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) Mur aya, 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. Van

Nostrand & Co. , 1961.

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

Composition and Processing on Weatherability of Coating-Grade

Asphalts, 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. Van

Nostrand & 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 steering

committee for this project, and the help of J. C. Weeks and T, R. Davis

in collecting the data.

USCOMM-NBS-DC