Note: Descriptions are shown in the official language in which they were submitted.
~:~2~
-- 1 --
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
37
21948A
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;
F7~
- 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-
~, ~
~f~ 8if2~
21948~
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
,~
21948A
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~
21948A
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
21948A
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
~.
21948A
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.
21948A
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
21948A
11
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.
