CA1282887C - Asphalt adhesives - Google Patents

Abstract

ABSTRACT OF THE DISCLOSURE
An adhesive is provided for adhering roofing shingles wherein the aldhesive is a blend of asphalt, an elastomer, a tackfying resin and a petroleum oil.

Description

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The pre~ent invent:ion relates to asphaltic compositions, and more particularly to an asphalt adhesive for retalning shingles. The adhesive i~ a blend of a~phalt, an elastomer, a tackifying resin and a petroleum oil. The present inventlon also relate~ to a roofing sheet or sningle employing thi~ elastomer-modlfied asphalt adheslve to retain the tabs of shingles agalnst windlift.
The use of adhesives, including asphaltic compounds, to provide a bond b~tween roo~ing shlnglas when applied to a roo~ is known. During a typical shingle manufacturing process, a pattern of adhesive is applied to the headlap portion o~ the shingles so that the tab portlon of the sub~equently laid courne of ~hlngles on the roo~ will adhere to the headlap portion of the lower course, to h~lp prevent wind upllft of the shingles. To seal properly, most 1 adh~si.ves or sealants require relatively high roof temperatures. U.S. Patent No. 4,559,267 discloses an adh~sive, of a compounded hitumen containing 3-20% rubber and/or thermoplastic resins, which re~uires an activation 5 temperature o~ at least 90~F. Many other adhesives require roof temperatures of about 135'F or higher. In relatively colder climates, these roof temperatures may never be reached or irl certain climates, these temperatures may not be reached until seasons subsequent ~o installation, which 10 may be months later. Consequently, under conditions where relatively low temperatures do not permit proper sealing of the adhesive, the shingles may be susceptible to blow-off in rela~ively higher winds. Another problem with conventional sealants is that colder temperatures tend to cause the 15 sealant on properly sealed shingles to become brittle and crack, resulting in bond failuxes and blow-o~fs.
U.S. Pa~ent No. 3,138,897 to McCorkle addrPsses the blow-off problem by using an adhesive strip on the shingle composed of distinct bands of two different 20 adhesives one is pressure sensi~ive while the other is temperature sensitive. As with conventional adhesives, the temperature sensitive adhesive of McCoxkle seals at relatively higher temperatures and since it doesn't even begin to get tacky until about 70'F, a second adhesive must 25 be used to permit sticking at lower temperatures, which is the pressure sensitive adhesive. The pressure sensitive adhesive is ~ffective only at lower temperatures since it loses its tackiness beyond temperatures of about lOO-F.
An asphalt-based adhesive has now been discovered 30 which is both pressure and temperature sensitive and ef~ectively works to greatl~ reduce the vulnerability o~ a shingle to the cold and wind. The adhesive of the instant invention remains tacky at roof temperatures as low as SO-F
to provlde a yood lnltial bond upon shingle installation at 35 these temperatures. While the adhesive seals the shingles at temperatures re~uired by most sealants, i.e., 135-F or higher, this adhesive also efectively sealfi the shingles at ~L~ 8~::8~7 roof temperature as low as 50F. This means that air temperature may be as low as 2~DF. Additionally, the adheslve retains appreciable strength and flexibility at lower temperatures which means that the adhesive does not get brittle and crack and will not break an already formed seal.
A further advantage of havin0 to apply only a single adhesive to the shinyle is provided ~y the adhesive of the instant invention. The cost benefits of ~pplying one sealant as opposed to two or more different sealants will beGome readily apparent to those skilled in the art, particularly when viewed from the standpoint of shingle manu~acturing.
According to this inventlon, there is provided an adhesive composition for retaining the tabs of shingles against windlift at temperatures of about 50~F and greater, comprising a blend of asphalt, an elastomer Gontaining about ~0% tribloGk styrene-butadiene-styrene eopolymer and about 20% dibloGk styrene-butadiene ~opolymer, a tackifylng resin and a petroleum oil, wherein the asphalt is ~haracterized by a kinematic viscosity in the range of from about 500 _ 100 poise to about 250 ~ 60 poise at 140F ~0G), a minimum viscosity of from about 110 cs ~Gentistokes) to about 80 centistokes at 275F
(135C), a penetration (ASTM D5 ~3) of from about 120 to about 300 dmm (decimillimeters) at ~7F (25C), and a rlng and ball so~tening point from about ~0F to about 130F.
A~Gording to this invention, there is also provided an asphalt roofing sheet having applied on at least one surfaGe the above-desGribed adhesive oomposition, a contact surface and a release material.
Embodiments of the invention will now be de6~ribed, by way of example, with referenGe to the accompanying drawings, in whiGh:
FIG. 1 is a plan view of the top side of a shingle with tab sealant adhesive;
FIG. 2 i~ a plan view of the hottom side of a shingle w~th ~ release surfaGe and a contact surfaGe;

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- 3a -FIG. 3 i~ a cross-sectional view of two shingles re~resenting their relative positions upon installation;
FIG. 4 is a cross-~eçtional ~iew of two shingles representing their relative positions in a pa~kage, before installation;
FIG. 5 is a graph of measured values for bond strengths of adhesives; and r-~, ~

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1 FIG. 6 is a graph o~ measur~d values for bond strengths of adhesives.

The adh~ive o~ the instant invention maintains 5 sufficient tack at ].ower temperatures to provide a quick and good initial bond duri.ng installation and will seal shingles at roof temperatures as low as 50-F when the air temperature may be as low as 25'F. Although the adhesive effectively seals at hiyher roof temperatures, it is especially useful 10 or winter applications in colder northern climates and provides good resistance to blow-off.
The present adhesive uses an asphalt characterized by a kinematic viscosity in the range of from about 500 poise ~ 100 to about 250 ~ 50 poise at 140'F (60 C) and a 15 minim~m viscosity of from about 110 cs (centistokes) to about 80 centistokes at 275 F (135~C). The asphalt can also be characterized by a penetration (ASTM D5 73) of from about 120 to about 300 dmm (deci millimeters) at 77-F (25 C). The asphalts of the instant invention exhibit a ring and ball 20 softening point from about 9 a F to about 130'F~
Particularly good results were obtained with paving grade asphalts having a kinematic viscosity of about SOO poise + 100 at 140F (60 C~, a minimum viscosity of about 110 cs at 275'F ~135~C~, a penetration of 120-175 dmm 25 at 77 F and a softening point ~rom about 110-F to about 120^F. These ~ypes of asphalts are known as viscosity-graded asphalt or AC-5 paving grade asphalt which is commercially available from Amoco Chemical Corporation ~Chicago, Illinois, V.S.~.).
- 30 Also useful is an AC~2.5 grade asphal~, also commercially available from Amoco, which has been mixed with oil to achieve a blend of about 90% AC-2.5 asphalt and 10%
oil. A suitable oil is one charac~eri~ed as a soft flux oil having a kinematic viscosity at 210-F of about 60-90 cs 35 which is commercially available from Marathon Oil Company (Findlay, Ohio, U.S.A.) and known as 432 oil. The asphalt blend is characterized by a so~tening point of about ,~

1 100-llO F, a penetration of from about 250-300 dmm at 77 F
and a viscosity of about 250 + 50 poise at 140'F.
The elastomers of the present invention are thermoplastic an~ æelected for their ability to impart 5 strength to the adhesive at colder temper~tures. As with conventional thermoplastic or~anic polymers, these elastomers can be processed, i~e., melted and extruded, and can be repeatedly heated and cooled with no substantial loss in their properties, especially their elastomeric 10 properties. Therefore, the elastomers employed herein substantially retain their properties when subjected to heating and cooling cycles. Particularly desirable is the retention of strength upon cooling the elastomer which gives strength and flexibility to the sealant at colder 15 temperatures-The ela~tomers employed in the present inventionare blosk copolymers, usually triblock (A~~-A) and may be linear or radial in structuxe. Either block, A or B, may comprise more than one monomer. Preferred are those 20 triblock copolymers having styrene or polystyrene as ~he "A"
block or end block units. Suitable elastomers include thermoplastic rubbers of styrene-butadiene-styrene (S-B-S), styrene-isopr~ne-styrene (S-I-S) and s~yrene-ethylene-butylene-styrene (S-E-B-S3 block copolymers. Preferred is a 25 styrene-butadiene styrene block copolymer, and especially one containing about 80% ~tyrene-butadiene-styrene triblock copol~ner and about 20% styrene-butadiene diblock copolymer.
Suitable elastomers are commercially available from the Shell Chemical Company (Houston, Texas, ~.S.A.) as Kraton~
30 thermoplastic rubbers, ~raton D and Kraton G grades. Most preferred is 5hell's Rraton D-1101 (S-~-S) rubber product which is a linear ~riblock copolymer containing about 80%
triblock styrene-butadiene-styrene copolymer and about 20%
diblock containing about 31% styrene and 69% butadiene, and 3~ which has a nominal molecular weight of about 100,000.
The tackifying resin can be any resinous material recognized in the art as enhancing the tack of the adhe ive ~8~

1 composition. Desirably, tackifiers will also impart cohesive strength or body to the adhesive so as to make it ~irm and not too soft. Sultable tackifying resins include rosin, rosin derivatives, polyterpene resins, thermoplastic 5 phenolic resins~ hydrogenated rosin esters o~
pentaerythritol, cumaroneindene and the like. Particularly ~ood results were obtained using a modified hydrocarbon resin commercially available from the Neville Chemical Company (Pittsburgh, Pennsylvania, U.S.A.) known as Nevpene~
10 9500 Tackifying Resin. Other suitable tackifiers commerci~lly available include terpene xesins called Wingtack~, from the Goodyear Tire & Rubber Co. (Akron, Ohio, U.S.A.) and Piccolite~ from Hercules Chemical Company (Wilmington, Delaware, UoS~A~ ) ~ It will be appreciated by lS those skilled in the art that the particular tackifier selected may vary with th~ specific asphalt used in order to achieve ~he desired propertie~ of ~he final adhesive.
The pe~roleum oil used herein is the resinous by~product of a lubricating oil tower used in the crude oil 20 refining process~ Generally, in the oil refi.ning process, a mixtur~ of volatile hydrocarbons is ~eparated from an asphaltic residue. one subsequent treatment of this residue is to further process it in a lu~ricating oil t~wex to yield a light fraction high in heterocyclic hydrocarbons and 25 another residue, This residue is a petroleum oil gen~rally characterized as being relatively eoft and high in resins.
When used in the instant invention, this petroleum oil is believed to aid in holding the other components toge~her and to impart a tacky characteristic to the sealant. Another 30 desirable characteristic of this resin-containing petroleum oil ls its thermal stability. Without being limited as to theory, it is believed tha~ thls petroleum oil compatibilizes the ~ystem to help prevent phase ~eparation.
This petroleum oil is also believed to improve the tackiness 35 of the adhesive at lower temperatures. This material is commercially available as Hub P-Resin from Bvrcke Associates, Inc~ (Great Neck, New York, U.S.A.~. Hub-P

1 resin is characterized by a viscosity at 210-F of 2300/2800, a pour point in 'F of +85, an acid number of about 0.15, and contains about 0.10% hard asphalt, 0O15% sulphur and 12.0%
carbon residue.
Conventional mixing or blending teehniques may be used to make the sealant. Generally, throughout the mix, the temperat~re is desirably maintained from about 260'F
~126.6-C) to about 360'F (182.2-C). Typically, the adhesive is cooled for packing an~ then melted for application to a 10 shingle. It may be desirable to circulate and maintain the adhesive at an elevated temperature during processing and application to the shingles to aid in the prevention of phase separation.
Satisfactory results have been obtained when the 15 ingredients of the sealant are present in an amount, in : approximate weight percent, of about 25% to about 80%
asphalt, about 3% to About 18% elastomer, about 5% to abou~
25% tackifying resin, and about 10% to about 50% petrol~um oil. Preferably, the sealant contains from about 35% to 20 about 60% asphalt, from about 5% to about 12% elastomer, ~rom about 8% to about 20% tackifying resin and from about 15% to about 35% petroleum oil. The most preferred composition is one consisting essentially of, in approximate weight percent, 42% to 48% paving grade asphalt, 10% to 11%
25 elastomer, 17% to 19% tacki~yiny resin and 22% to 28%
petroleum oil.
The present invention also provides a roofing shlngle employing the above-described adhesive.
With reference to the drawings, the preferred embodiment~, FIG. 1 shows the top surface 11 of a shin~le 10 havin~ the tab sealant adhesive 12 applled in the headlap portlon 13 of the shingle. The shingle 10 can be any conventlonal shin~le known in the art. Particularly suitable shingles are those made of a~phalt reinforced by glae~ fibers, as exemplified by U.S. Patent No. 3,332,830.
The adhesive i~ preferably applied to the headlap portion 13 o~ the shin~le ~.

1 and holds down the overlying tabs 15 o~ a shingle in the nex~ upper row when installed on a roof. Although FIG. 1 shows the adhesive 12 applied as three discontinuous strips, the adhesive can be applied in any form or con~iguration 5 which provides an ade~uate surface area for adhering an overlying shingle. For example, the adhesive may be applied as one continuous strip, or any combination of a number of continuous and/or discontinuous strips of varyinq dimensions. The sealant may also be placed anywhere on the 10 shlngle which would he effective in adhering overlapping shingles, including the bottom side of the shingle.
As shown in FIG. 3, the top surfaces 11 of the shingles are typically covered with granules 18 of crushed rock, and the adhesive 12 is applied over the granules 18.
FIG. 2 shows the bottom surface 17 of a shingle 10 having a strip of release material 14 and a strip of contact surface 16 on the shingle tab 15. Although this location represents the preferred embodiment, the release material 14 and the contact surface 16 may be located on the top surface 20 11 of a shingle. When the stxip of release material 14 is located on the bottom surface 17 of the shingle in a position which coxresponds to the position of the strip of tab sealant adhesive 1~ on the top ~urfac~ 11, as shown in FIG. 4, the shingles are prevented from sticking together 25 during packing where they are usually stacked upon each other~ The release paper may be removed or left on during installation without any adverse effect on the per~ormance of the shingle.
The release material can be of any material which 30 does not adhere to ~he ~ealant so as to prevant the shingles ~rom stickiny to each other, particularly before installation. Suitable release materials include paper or polyesters which have to be treated with a non-adhering substance such as silicone or fluorocarbons. Alternatively, 35 the release material may be a liqu~d or emulsion of silicone- or fluorocarbon-based substances which are applied directly to the shingla by any method, including spraying.

21948A ~
g 1 Silicone-tre~ted pap~r is colNmercially available from James River Corporation ~Parchment, MI, U.S.A.~ and a silicone-based emulsion for spray applications is commercially available from Paper-Chem Labs (Rockhill, North 5 Caxolina, U.S.A.).
As shown in FI~. 3, the con~act surface 16 works together with ~he adhesive 12 to form an extra~tight bond between ove.rlapping shingles after installation. The location of the contact surface 16 on ~he bottom surface 17 10 of one shingle 10 corresponds ~o the pos.ition of the tab sealant 12 on the top surface 11 of the underlying shingle 10 to form a tight bond between shingles upon installation.
The contact surface 16 may be covered with any material to which the adhesive will adhere, especially in 15 colder temperatures~ Suitable materials include polyester, polypropylene, polyethylene, polybutylene, a copolymer of polyethylene and vinyl acetate and may be applied in any form, including strips, films, liquids or emulsions.
Preferred is a polyPster film commercially available as 20 ~ylax~ from E~I. DuPont de Nemours & Co. (Wilmington, Delaware, U.S.A.).
The following Examples illustrate ~e invention.
Example 1 The following experiment was conducted to test the 25 bond strength of adhesives after shingles bearing the adhesives were sealed at about 135-F. The bond strength test was conducted by sealing, at 135-F for 16 hours, two overlapping pieces of roofing shingles bearing various adhesives. Upon cooling, the bond s~rengths o~ the 30 adhesives were measured at various temperatures. To measure the bond strengths of the adhesives, an Instron tensile pulling machine, or equivalent apparatus, was used. The machine permits the bottom and top shingle sections to be clamped into place and then pulled while a load cell 35 attached to the upper clamp measures the amount of force required to pull the shingles apart, which is recorded in units of pounds.

l Three asphaltic adhesives were tested for bond strength usir-g this method and are identified in Table 1.
Adhesives A and B represented formulas of the instant invention while adhesive C was a standard commercially 5 available asphaltic adhesive known as Seal Rite~ , commercially available from Gwens-Corning Fi~erglas Corporation (Toledo, Ohio, U.S.A.~.
Table 1 Adhesive Content A asphalt~ s.p. 110 F-120 F
elastomer tackifying resin petroleum oil B asphalt, s~p. 100-F-110-F
elastomer tackifying resin petroleum oil C asphalt - approx. 60% propane washed ~ approx. 40% roofing grade The results are summarized in FIG. 5, which is a graph depicting the measured bond strengths of adhesives A, ~ and C represented by lines A, B and C, respectively. Each data point on the graph represents a value which-is the av~rage of values obtained from several tests under similar 30 conditions. The bond strength values obtained for adhesive B at 50-F and 75-F were the same values obtained for adhesive A at these temperatures. Line B is depicted as a separate dashed line for purposes of clarit~ in presenting the data.
As can be seen ~rom the test results, the adhesives of the instant invention retained substantially 1 greater bond strength as compared to the standard adhesive at 50-F when the temperature of the shingles was reduced after sealing at 135-F.
Example 2 The above adhesives were also tested according to the Underwriter's Laboratory wind test UL 997 for shingles.
To conduct the test~ shingles bearing the adhesive were stapled to a plywood deck measuring about 54 in. by 4 ft.
The shingles were then sealed in an oven at a temperature of lO about 135-140^F for about 16 hours. After the deck cooled to room temperature, it was placed at a 4 in 12 slope and a 60 mph wind was blown on the deck. It was found that after

2 hours, no tabs lifted on shingles bearing adhesives A and C, while 3 tabs lifted after 45 minutes on shingles bearing 15 adhesive B. Consequently, the inventive adhesive containing the harder asphalt (Adhesive A~ provided better resistance than the inventive adhesive with the softer asphalt ~ (Adhesive B) against the winds encountered in the Underwriter'~ Laboratory wind test.
20 ~ E~
An experiment was conducted to test the bond strength of adhesives at the same temperature at which shingles bearinq the adhesive were sealed.
To test the adhesive, the shingles were placed 25 together and allowed to adhere at testing temperature for a period of about 16 to 24 hours. A~ the same temperature, the bond strength of the adhesive wa~ tested using the same apparatus and testing technique described in ~xample 1.
When ~he testing temperature was below room temperature, 30 i.e., 50~F, the shin~les were cooled for 1 hour at 50-F
before sealing them.
The same thrPe adhesives, A and B of the invention and C, a standard adhesive, as in Example 1, were tested.
The results are summarized in FIG. 6 which is a 35 graph depicting the measured bond strengths of adhesives A, B and C, represented by lines A, ~ and C respectively, according to the procedure descrlbed above. Each data point .1948A
1~
1 on the graph represents a value which is the average of values obtalned from several tests under simi.lar conditions.
As carl be seen in FIG. 6, the inventive adhesives, ~ and B, provided especially good initial cold-temperature 5 bonding strenqth a~ 50-F as compared to the standard adhesive, C, which demonstrated no bond strength at 50'F, 75-F and lOO F.
Although the invention has been described in terms of specific embodiments of a manner the invention may be 10 practiced, this is by way of illustration only and the invention is not necessarily limited thereto since alternative embodiments and opera~ing techniques will become apparent to those skilled in the art. Accordingly, modifications are contemplated which can be made without l5 departing from the spirit of the described lnvention.

Claims (11)

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

1. An adhesive composition for retaining the tabs of shingles against windlift at temperatures of about 50°F and greater, comprising a blend of asphalt, an elastomer containing about 80% triblock styrene-butadiene-styrene copolymer and about 20% diblock styrene-butadiene copolymer, a tackifying resin and a petroleum oil;
wherein the asphalt is characterized by a kinematic viscosity in the range of from about 500 ? 100 poise to about 250 ? 50 poise at 140°F (60°C), a minimum viscosity of from about 110 cs (centistokes) to about 80 centistokes at 275°F (135°C), a penetration (ASTM D5 73) of from about 120 to about 300 dmm (decimillimeters) at 77F (25°C), and a ring and ball softening point from about 90°F to about 130°F.

2. An adhesive composition as in claim 1, wherein the blend contains about 25-80% asphalt, 3-18%
elastomer, 5-25% tackifying resin and 10-50% petroleum oil.

8. An adhesive composition as in claim 1, wherein the blend contains about 35 60% asphalt, 5-12 elastomer, 8-20% tackifying resin and 15-35% petroleum oil.

4. An adhesive composition as in claim 1, wherein the blend contains in approximate weight percent, about 42-48% asphalt, 10-11% elastomer, 17-19% tackifying resin and 22-28% petroleum oil.

5. An adhesive composition as in claim 1, wherein the blend contains, in approximate weight percent, 45.5% asphalt, 10.4% elastomer, 18.3% tackifying resin and 25.8% petroleum oil.

6. An adhesive compsoition as in claim 1, 2 or 3, wherein the diblook copolymer of said elastomer contains about 31% styrene and about 69% butadiene.

7. An asphalt-based roofing sheet having superposed thereon an adhesive composition, for retaining the tabs of shingles against windlift at temperatures of about 50°F and greater, a contact surface, and a release material, wherein said adhesive comprises a blend of asphalt, an elastomer containing about 80% triblock styrene-butadiene-styrene copolymer and about 20% diblock styrene-butadiene copolymer, a tackifying resin and a petroleum oil:
wherein the blend contains about 25-80% asphalt, 3-18% elastomer, 5-25% tackifying resin and 10-50%
petroleum oil;
wherein the asphalt is characterized by a kinematic viscosity in the range of from about 500 ? 100 poise to about 250 ? 50 poise at 140°F (60°C), a minimum viscosity of from about 110 cs (centistokes) to about 80 centistokes at 275°F (135°C), a penetration (ASTM D5 73) of from about 120 to about 300 dmm (decimillimeters) at 77°F l25°C), and a ring and ball softening point from about 90°F to about l30°F; and wherein the petroleum oil is a resinous by-product of a lubricating oil tower used in the crude oil refining process.

8. A roofing sheet having tabs, a headlap portion, a top surface and a bottom surface, where said top surface has applied thereon an adhesive in the headlap portion of said sheet and said bottom surfaces has a release material in said headlap portion of the sheet and a contact surface on the tabs, wherein said adhesive seals said sheets at 50°F and greater and said adhesive is a blend comprising asphalt, an leastomer containing about 80% triblock styrene-butadiene-styrene copolymer and about 20% diblock styrene-butadiene copolymer, a tackifying resin and a petroleum oil:

wherein the asphalt is characterized by a kinematic viscosity in the range of from about 500 ? 100 poise to about 250 ? 50 poise at 140°F (60°C), a minimum viscosity of from about 110 cs (centistokes) to about 80 centistokes at 275°F (135°C), a penetration (ASTM D5 73) of from about 120 to about 300 dmm (decimillimeters) at 77°F (25°C), and a ring and ball softening point from about 90°F to about 130°F; and wherein the petroleum oil is a resinous by-product of a lubricating oil tower used in the crude oil refining process.

9. A pair of superimposed shingles partially overlapped to form an overlapping area in which one shingle has applied on its surface an adhesive composition and the other shingle bears a contact surface for adhering said adhesive, wherein said adhesive is a composition for retaining the tabs of said shingles against windlift at temperatures of about 50°F and greater and said adhesive is a blend comprising asphalt, an elastomer containing about 80% triblock styrene-butadiene-styrene copolymer and about 20% diblock styrene-butadiene copolymer a tackifying resin and a petroleum oil:
wherein the asphalt is characterized by a kinematic viscosity in the range of from about 500 ? 100 poise to about 250 ? 50 poise at 140°F (60°C), a minimum viscosity of from about 110 C5 (centistokes) to about 80 centistokes at 275°F (135°C), a penetration (ASTM D5 73) of from about 120 to about 300 dmm (decimillimeters) at 77F (25°C), and a ring and ball softening point from about 90°F to about 130°F; and wherein the petroleum oil is a resinous by-product of a lubricating oil tower used in the crude oil refining process.

10. An asphalt-based roofing sheet having superposed thereon an adhesive composition for adhering the roofing sheet to an adjacent roofing sheet, a contact surface, and a release material, wherein said adhesive is one comprising a blend of asphalt, an elastomer containing about 80% triblock styrene-butadiene-styrene copolymer and about 20% diblock styrene-butadiene copolymer, a tackifying resin and a petroleum oil:
wherein the blend contains about 25-80% asphalt, 3-18% elastomer, 5-25% tackifying resin and 10-50%
petroleum oil;
wherein the asphalt is characterized by a kinematic viscosity in the range of from about 500 ? 100 poise to about 250 ? 50 poise at 140°F (60°C), a minimum viscosity of from about 110 cs (centistokes) to about 80 centisoles at 275°F (135°C), a penetration (ASTM D5 73) of from about 120 to about 300 dmm (decimillimeters) at 77°F (25°C), and a ring and ball softening point from about 90°F to about 130°F.

11. The roofing sheet of claim 10, comprising an asphalt roofing membrane.