High durometer, polymeric roofing shingles with varying colors and shades of color may be prepared from a composition of matter comprising 100 parts by weight of a ethylene-propylene-diene (EPDM) terpolymer; from 25 to about 400 parts by weight of at least one non-combustible filler per 100 parts of ethylene-propylene-diene (EPDM) terpolymer; from 0 to about 125 parts by weight of at least one combustible filler, per 100 parts of ethylene-propylene-diene (EPDM) terpolymer; from 0 to about 135 parts by weight of a thermoplastic modifying polymer; from 0 to about 10 parts by weight of reinforcing fibers, per 100 parts of ethylene-propylene-diene (EPDM) terpolymer; from about 20 to about 75 parts by weight of a processing oil per 100 parts of ethylene-propylene-diene (EPDM) terpolymer; and from about 1 to about 6 parts by weight of a sulfur cure package having at least two curing accelerators. Fiber reinforced, high durometer, EPDM-based roofing shingles of the present invention are a suitable replacement for traditional slate, wood or asphalt roofing shingles used to cover sloped roofs. A method is further provided for covering sloped roofs comprising applying a plurality of the fiber reinforced, high durometer EPDM-based roofing shingles of the present invention to a sloped roof in a preselected installation pattern.

TECHNICAL FIELD OF THE INVENTION 
The present invention relates generally to covering elements, preferably 
for roofs, of the type commonly known as roofing shingles. More 
particularly, the present invention relates to uncolored and colored, 
fiber reinforced, high durometer EPDM-based polymeric roofing shingles, 
having improved heat aging, ozone, oxidation and moisture resistance as 
compared to traditional asphalt-based roofing shingle compositions. The 
fiber-reinforced EPDM-based polymeric roofing shingles of the present 
invention feature virgin and recycled EPDM polymer compositions as well as 
compositions containing at least 100 parts by weight of recycled EPDM 
materials. 
BACKGROUND OF THE INVENTION 
High durometer roofing shingles used to cover sloped roofs are known in the 
art. Typically, these roofing shingles are used to replace shingles, 
shakes, or other covering elements made of slate, wood, asphalt, or other 
hard, natural materials known in the art. These shingles are designed 
essentially to match the size, shape and texture of the shingle to be 
replaced, thereby maintaining essentially the same installation pattern, 
architectural perspective or aesthetic appearance for the roof on which 
they are placed. 
Heretofore, polymer blends of vulcanized scrap rubber or ground rubber and 
polyolefin resin have consistently been employed to produce these high 
durometer roof covering elements. For example, U.S. Pat. Nos. 5,312,573 
and 5,157,082 refer to processes for the production of useful articles 
made from reclaimed vulcanized rubber, preferably from tires, and 
polyolefin resins such as polyethylene or polypropylene. In each instance, 
the major component of the polymer blend is the inert vulcanized rubber. 
More particularly, the inert vulcanized scrap rubber is often reclaimed 
from recycled tires, as noted hereinabove, or from off-specification 
rubber compounds available from tire manufacturing facilities or various 
other industrial facilities. Such rubber typically includes rubber 
materials such as natural rubber, synthetic polyisoprene, styrene 
butadiene rubber (SBR), polybutadiene, butyl rubber (IR) or the like or 
mixtures and blends thereof. While such rubber may be particularly useful 
for the processes developed in the above-mentioned patents, these rubbers 
are not easily converted into new products and must oftentimes be employed 
with additional polymeric ingredients and/or compatibilizers in order to 
form the articles desired. For example, both patents noted hereinabove 
require the use of additional thermoplastic resins such as polyethylene 
and polypropylene, or copolymers thereof. 
Ethylene-propylene-diene (EPDM) terpolymers have gained wide acceptance in 
the construction industry as a suitable material for single-ply EPDM-based 
roofing membrane or sheeting compositions. To the extent that EPDM may be 
included in the scrap or ground vulcanized rubber products of the prior 
art, EPDM has not been used in significant portions and is essentially 
inert in the scrap rubber compositions, acting, for the most part, as a 
filler material since the rubber has already been cured. Nevertheless, 
single-ply EPDM-based roofing membrane or sheeting has rapidly gained 
acceptance as an effective covering and barrier to prevent the penetration 
of moisture through industrial and commercial flat roofs. Such EPDM 
membranes have outstanding weathering resistance, flexibility and low 
temperature properties. EPDM-based polymeric roofing compositions are 
normally prepared by vulcanizing or curing it in the presence of sulfur or 
sulfur-containing compounds, such as mercaptans. The use of EPDM is also 
advantageous in that it can be easily mixed with other ingredients, such 
as mineral fillers, processing oils and the like to provide a suitable 
single-ply polymeric roofing membrane composition. These membranes are 
typically applied to the roof surface in a vulcanized or cured state, but 
are flexible enough to be transported in the form of a roll. However, 
these membranes are not used on sloped roofs, would be difficult to 
install on sloped roofs, and do not possess the required hardness to be 
suitable for use on sloped roofs. 
Traditional asphalt-based roofing shingles are well known, but typically do 
not weather well in cold temperatures. These traditional roofing shingles 
are also somewhat susceptible to damage by hail. Furthermore, it is known 
that roofing shingles of this type do not provide the heat aging, ozone, 
oxidation and moisture resistance of roofing membranes employing EPDM 
terpolymers. Slate roofing shingles, while suitable for most purposes, are 
very heavy and very expensive in comparison to asphalt or polymeric 
roofing shingles. Thus, neither of these alternatives, i.e., asphalt or 
slate roofing shingles are particularly desirable. 
Roofing shingles of the type described hereinbelow are generally stiff, and 
can be molded into flat sheets of essentially any size or shape. Where the 
roofing shingle to be developed will replace slate or asphalt shingles, it 
has been found that production of a rectangular roofing shingle which is 
about 0.25 inches thick, about 18 inches long and about 12 inches wide, is 
desirable. It will be appreciated, however, that other sizes and shapes 
may be more suitable and preferred when used to replace shingles of other 
types or when the slate or asphaltbased shingles being replaced are not of 
that same general size or shape, and the present invention should not be 
limited thereto. 
Accordingly, it is believed desirable to develop low cost, high durometer 
polymeric roofing shingles to replace traditional shingles, shakes or 
other covering elements made of slate, wood, asphalt, and the like. The 
roofing shingles should also impart improved burn resistivity, weathering 
resistance, stress-strain properties, die-C tear characteristics, Shore 
"A" hardness and protective properties over the traditional roofing 
shingles used to cover sloped roofs. 
The resulting roofing shingle compositions of the present invention are 
seen as being useful to the manufacture of high durometer roofing 
shingles, suitable as a replacement for traditional roofing shingles used 
to cover sloped roofs, where aesthetic appearance, improved burn 
resistivity, resistant to hail and wind damage and weathering performance 
are some of the more desirable characteristics of roofing shingles. 
SUMMARY OF THE INVENTION 
It is, therefore, an object of the present invention to provide a high 
durometer polymeric roofing shingle suitable for covering sloped roofs. 
It is another object of the present invention to provide a high durometer, 
polymeric roofing shingle, as above, which comprises 
ethylenepropylene-diene (EPDM) terpolymer as the polymeric component of 
the roofing shingle. 
It is still another object of the present invention to provide a high 
durometer, EPDM-based roofing shingle, as above, which further comprises 
reinforcing fibers or filaments. 
It is yet another object of the present invention to provide a high 
durometer, EPDM-based roofing shingle, as above, which is sulfur curable. 
It is still a further object of the present invention to provide a high 
durometer, EPDM-based roofing shingle, as above, which comprises an EPDM 
rubber dust to impart color to the roofing shingle composition. 
It is a further object of the present invention to provide a polymeric 
roofing shingle, as above, which comprises 100 weight percent recycled 
EPDM as the polymeric component of the roofing shingle. 
It is yet a further object of the present invention to provide a polymeric 
roofing shingle, as above, which is composed entirely of recycled 
material. 
It is still a further object of the present invention to provide a 
polymeric roofing shingle, as above, optionally comprising mineral fillers 
and fire retardant additives. It is yet a further object of the present 
invention to provide a polymeric roofing shingle, as above, having 
improved heat aging, ozone, oxidation and moisture resistance as compared 
to traditional roofing shingles made of asphalt. 
It is still a further object of the present invention to provide a 
polymeric roofing shingle, as above, having improved stress-strain 
properties, die C tear resistance and Shore "A" hardness as compared to 
traditional roofing shingles made of asphalt. 
It is yet another object of the present invention to provide a polymeric 
roofing shingle, as above, having an increased stiffness (i.e., more 
resistant to wind uplift) as compared to traditional roofing shingles made 
of asphalt. 
It is still another object of the present invention to provide a polymeric 
roofing shingle, as above, having improved burn resistivity as compared to 
traditional roofing shingles made of asphalt. 
It is yet a further object of the present invention to provide a polymeric 
roofing shingle, as above, having an improved low temperature performance 
as compared to traditional roofing shingles made of asphalt. 
It is still a further object of the present invention to provide a 
polymeric roofing shingle, as above, having an improved resistance to hail 
damage as compared to traditional roofing shingles made of asphalt. 
It is yet a further object of the present invention to provide a method for 
covering sloped roofs using the rubber roofing shingle described herein. 
At least one or more of the foregoing objects, together with the advantages 
thereof over the known art relating to roofing shingle compositions, which 
shall become apparent from the specification which follows, are 
accomplished by the invention as hereinafter described and claimed. 
In general, the present invention provides, a normal colored i.e., dark 
gray or black, or a uniquely colored, e.g., red, green, tan, etc., high 
durometer ethylene-propylene-diene (EPDM) roofing shingles comprising 100 
parts by weight of an amorphous, sulfur-curable, ethylene-propylene-diene 
(EPDM) terpolymer, having a crystallinity of less than about 1.5 percent, 
as the polymeric component, from about 20 to about 135 parts by weight of 
at least one thermoplastic modifying polymer per 100 parts of the 
ethylene-propylene-diene (EPDM) terpolymer, from about 25 to about 400 
parts by weight of a non-combustible filler, per 100 parts of 
ethylene-propylene-diene (EPDM) terpolymer, from 0 to about 125 parts by 
weight of a combustible filler, per 100 parts of the 
ethylene-propylene-diene (EPDM) terpolymer; from 0 to about 20 part by 
weight of reinforcing glass fibers per 100 parts of the 
ethylene-propylene-diene (EPDM) terpolymer, from 20 to about 75 parts by 
weight of a processing oil per 100 parts of the ethylene-propylene-diene 
(EPDM) terpolymer, from about 1 to about 6 weight percent of a sulfur cure 
package per 100 parts of the ethylene-propylene-diene (EPDM) terpolymer, 
and optionally from 0 to about 150 parts by weight of a colored EPDM 
rubber dust per 100 parts of the ethylene-propylene-diene (EPDM) 
terpolymer. The acceptable roofing shingles of the present invention may 
be manufactured using 100 percent recycled EPDM-based composition. These 
recycled compositions include a mixture of uncured roof shingle edge 
trimmings and/or cured flashing trimmed from the edges of compression 
molded EPDM-based roofing shingles. 
The present invention also provides a method for covering sloped roofs 
comprising: applying a plurality of the normal colored or uniquely 
colored, fiber-reinforced, high durometer roofing shingles of the present 
invention to a sloped roof in a preselected installation pattern, the 
roofing shingles being prepared from a composition of matter comprising 
100 parts by weight of an amorphous, sulfurcurable, 
ethylene-propylene-diene (EPDM) terpolymer, having a crystallinity of less 
than about 1.5 percent, as the polymeric component, from about 20 to about 
135 parts by weight of at least one thermoplastic modifying polymer per 
100 parts of the ethylene-propylene-diene (EPDM) terpolymer, from about 25 
to about 400 parts by weight of at least one non-combustible filler, per 
100 parts of the ethylenepropylene-diene (EPDM) terpolymer, from 0 to 
about 125 parts by weight of a combustible filler, per 100 parts of the 
ethylene-propylene-diene (EPDM) terpolymer, from 0 to about 20 part by 
weight of reinforcing fibers per 100 parts of the ethylene-propylene-diene 
(EPDM) terpolymer, from 20 to about 75 parts by weight of a compatible 
processing oil, per 100 parts of the ethylene-propylene-diene (EPDM) 
terpolymer, from about 1 to about 6 weight percent of a sulfur cure 
package per 100 parts of the ethylene-propylene-diene (EPDM) terpolymer, 
and optionally from 0 to about 150 parts by weight of a colored EPDM 
rubber dust per 100 parts of the ethylene-propylene-diene (EPDM) 
terpolymer.

DETAILED DESCRIPTION OF THE INVENTION 
As described hereinabove, the roofing shingle compositions of the present 
invention comprises an ethylene-propylene-diene terpolymer as the rubber 
component. The term EPDM is used in the sense of its definition as found 
in ASTM D-1418-94 and is intended to mean a terpolymer of ethylene, 
propylene and a diene monomer. Although not to be limited thereto, 
illustrative methods for preparing such terpolymers are found in U.S. Pat. 
No. 3,280,082, the disclosure of which is incorporated herein by 
reference. Other illustrative methods can be found, for example, in Rubber 
and Chemistry & Technology, Vol. 45, No. 1, Division of Rubber Chemistry 
(March 1992); Morton, Rubber Technology, 2d ed., Chapter 9, Van Nostrand 
Reinhold Company, New York (1973); Polymer Chemistry of Synthetic 
Elastomers, Part II, High Polymer Series, Vol. 23, Chapter 7, John Wiley & 
Sons, Inc. New York (1969); Encyclopedia of Polymer Science and 
Technology, Vol. 6, pp. 367-68, Interface Publishers, a division of John 
Wiley & Sons, Inc., New York (1967); Encyclopedia of Polymer Science and 
Technology, Vol. 5, p. 494, Interface Publishers, a division of John Wiley 
& Sons, Inc., New York (1966); and Synthetic Rubber Manual, 8th ed., 
International Institute of Synthetic Rubber Producers, Inc. (1980). 
The preferred EPDM terpolymers of the present invention are substantially 
amorphous. That is, the EPDM terpolymer comprising the rubber component of 
the roofing shingles of the present invention should have less than about 
1.5 percent crystallinity. More particularly, the EPDM roofing shingle 
composition of the present invention should have 100 parts by weight of an 
amorphous EPDM containing up to about 1.5 percent crystallinity, and more 
preferably, up to about 1.1 percent crystallinity. 
Any EPDM containing less than 1.5 percent, crystallinity from the ethylene 
component and exhibiting the properties discussed hereinbelow should be 
suitable for use in the present invention. Typically, amorphous EPDMs 
having less than about 68 weight percent ethylene and from about 1.5 to 
about 4 weight percent of the third monomer (diene portion) with the 
balance of the terpolymer being propylene or some other similar olefin 
type polymer is desired. Such EPDMs also preferably exhibit a Mooney 
viscosity (ML/1+4 at 125.degree. C.) of about 40 to 65 and more 
preferably, of about 45 to 55. Preferably, the EPDM does not have more 
than about 4 weight percent, and more preferably, not less than 2 weight 
percent, unsaturation. 
Typical EPDM terpolymers having less than 1.5 percent crystallinity are 
available from Uniroyal Chemical Co. under the tradename Royalene.RTM.. 
The most preferred EPDM terpolymer is an amorphous EPDM terpolymer having 
a Mooney Viscosity (ME/1+4 at 125.degree. C.) of about 47, an ethylene 
content of about 69 weight percent, about 2.7 weight percent unsaturation, 
and less than 1.5 percent crystallinity. Another preferred amorphous EPDM 
terpolymer is commercially available from DSM Copolymer under the 
trademark Keltan.RTM. and has a Mooney Viscosity (ML/1+4 at 125.degree. 
C.) of about 50, an ethylene content of about 69 weight percent, about 2.6 
weight percent unsaturation, less than 1.5 percent crystallinity and a 
specific gravity of about 0.87 at 23.degree. C. Yet another polymer having 
utility as the base polymer in the roof shingle composition is available 
as a developmental EPDM polymer produced by Exxon Chemical Company under 
the trademark Vistalon.RTM.. This EPDM terpolymer has a Mooney Viscosity 
(ML/1+4 at 125.degree. C.) of about 52, an ethylene content of about 69 
weight percent, about 2.9 weight percent unsaturation and less than 1.5 
percent crystallinity. In this invention, amorphous EPDM terpolymers are 
preferred over more crystallinity EPDM terpolymers. 
The diene monomer utilized in forming the EPDM terpolymer is preferably a 
non-conjugated diene. Illustrative examples of non-conjugated dienes which 
may be employed are dicyclopentadiene, alkyldicyclopentadiene, 
1,4-pentadiene, 1,4-hexadiene, 1,5-hexadiene, 1,4-heptadiene, 
2-methyl-1,5-hexadiene, cyclooctadiene, 1,4-octadiene, 1,7-octadiene, 
5-ethylidene-2-norbornene, 5-npropylidene-2-norbornene, 
5-(2-methyl-2-butenyl)-2-norbornene and the like. 
It will be appreciated that the subject roofing shingles may comprise 100 
parts by weight of an amphorous EPDM as the sole elastomeric polymer for 
the roof shingle composition. However, it is contemplated that more than 
one EPDM having less than 2 weight percent crystallinity may be employed. 
For example, roof shingles of the present invention may include a flame 
retardant package which includes an amorphous EPDM as the polymer binder 
as well as the amorphous EPDM polymeric component. As more specifically 
detailed hereinbelow, flame retardant packages commercially available from 
Great Lakes Chemical Corporation (formerly Anzon Chemical Company) under 
the tradename Fyrebloc, include from about 10 to 20 percent by weight EPDM 
and, more preferably, from about 15 to about 17.5 percent by weight EPDM, 
as the polymeric binder for the total flame retardant package. Thus, the 
amount of EPDM employed includes the EPDM from the flame retardant package 
as well as that which is directly compounded in the roof shingle 
composition as virgin EPDM terpolymer. It will also be noted that certain 
fillers such as cryogenically or ambiently ground EPDM rubber may include 
EPDM terpolymers. However, because these fillers do not contain virgin 
EPDM terpolymers, they have not been figured in the calculation of parts 
or percentages employed. 
When EPDM terpolymers having more than 2 percent crystallinity from the 
ethylene component are employed, these EPDMs preferably should contain at 
least about 65 weight percent ethylene and from about 2 to about 4 weight 
percent unsaturation (diene monomer) with the balance of the terpolymer 
being propylene or some other similar olefin type polymer. Although not 
necessarily limiting, the Mooney viscosity of such EPDMs should be no more 
than about 60 and should have less than about 3.5 weight percent 
unsaturation. However, EPDMs with Mooney viscosities of about 45 to about 
50 are preferred. Non-conjugated dienes like those exemplified above can 
also be used for these types of EPDMs as well. It will be appreciated, 
however, that the total EPDM terpolymers utilized will be characterized as 
having 2 percent or less crystallinity. 
As noted hereinabove, at least one impact modifying polymer selected from 
the group consisting of polyolefm resins or copolymers thereof may be 
blended with the EPDM to form the polymeric component of the EPDM-based 
shingle composition. By the term "impact modifying polymer" it is meant 
that these polymers provide the roofing shingle composition with more 
stiffness and may increase the impact strength of the composition. Higher 
shingle stiffness also increases resistance to wind uplift. Essentially 
any polyolefin resin or copolymer thereof capable of imparting the 
characteristics described hereinabove may be suitable for the roofing 
shingle composition of the present invention. Preferably, 0 to about 135 
percent by weight of the roofing composition may be made from these impact 
modifying polymers, per 100 parts EPDM terpolymer. Most preferred, with 
respect to the polyolefin resins, are low density polyethylene (LDPE), 
linear low density polyethylene (LLDPE), high density polyethylene (HDPE), 
and atactic and isostatic polypropylene. Suitable copolymers include, but 
are not necessarily limited to, ethylene-propylene copolymers, 
ethylene-butene copolymers, and ethylene-octene copolymers. Generally, the 
preferred polyolefin resins and copolymers thereof should provide high 
impact strength and better resistance to wind uplift to the resultant 
roofing shingle composition. 
One particularly useful polyolefin resin is LDPE 722 M, a low density 
polyethylene commercially available from Dow Plastics. LDPE 722 M has a 
melt flow index of 8 grams/10 minutes, peak melt temperature of 
112.degree. C. as determined by DSC and a specific gravity of 0.9160 g/cc 
at 23.degree. C. Differential scanning calorimetry (DSC) is used to 
measure the emission or consumption of heat accompanying a physical change 
or a chemical reaction as a function of temperature or time in the range 
of -150.degree. C. to 725.degree. C. 
Also of particular use are certain LLDPEs, which may also be considered 
ethylene-octene copolymers, such as are available from Dow Plastics under 
the tradename Dowlex.RTM.. There are a variety of Dowlex ethylene-octene 
copolymers which generally differ in their peak melt temperatures and 
specific gravities. For example, Dowlex 2027 has a peak melt temperature 
of 113.degree. C. as determined by DSC and a specific gravity of 0.941 
g/cc at room temperature whereas Dowlex 2038 and Dowlex 2045 have peak 
melt temperatures of 127.degree. C. and 124.degree. C., respectively, and 
specific gravities of 0.935 g/cc and 0.920 g/cc, respectively. 
A preferred HDPE resin is Nova 79 G produced by NOVA Chemical Ltd. This 
resin has a peak melt temperature of 132.degree. C. and a specific gravity 
of about 0.96 g/cc at 23.degree. C. Another suitable HDPE is 62013 
commercially available from Dow Plastics. HDPE 62013 has a peak melt 
temperature of 131.degree. C. and a specific gravity of 0.945 g/cc at 
23.degree. C. 
Other resins which may have utility in this invention include a number of 
HDPE resins produced by Dow Plastics. Some of the typical properties of 
these resins are shown in Table A hereinbelow. 
TABLE A 
______________________________________ 
Comparison of Suitable High Density 
Polyethylene (HDPE) Resins 
MELT INDEX (MI) SPECIFIC GRAVITY 
TRADENAME (GRAMS/10 MINUTES) (GRAMS/CC) 
______________________________________ 
04352N 4 0.952 
06153C 6.3 0.953 
08254N 7 0.954 
10062N 10 0.962 
12350N 12 0.960 
17350N 17 0.950 
25355N 25 0.955 
30360M 30 0.960 
40360M 38 0.958 
______________________________________ 
Also preferred are ethylene-propylene copolymers (EPMs) such as those 
available from Exxon Chemical Company under the registered tradename 
Vistalon.RTM. and DSM Copolymer under the registered tradename 
Keltan.RTM.. The term EPM is used in the sense of its definition as found 
in ASTM D-1418-94 and is intended to mean a copolymer of ethylene and 
propylene. Some typical properties of ethylene-propylene copolymers 
include having an ethylene content of from about 45 percent to about 72 
percent by weight, a Mooney viscosity (ML/4 at 125.degree. C.) of from 
about 25 to 55, a glass transition temperature of from about 40.degree. C. 
to about -60.degree. C. Ethylene-propylene copolymers are without any 
unsaturation, and these polymers have excellent long-term heat and ozone 
aging resistance as well as provide a smooth appearance to the molded 
shingle. A typical EPM suitable for use in the present invention is 
available from DSM Copolymer under the tradename Keltan.RTM.740. This EPM 
has a Mooney viscosity (ML/4 at 125.degree. C.) of about 63 and an 
ethylene content of about 60 weight percent. 
Other EPMs are also suitable. For instance, Keltan.RTM. 3300A and 4200A 
have Mooney viscosities (ML/1+4 at 125.degree. C.) of about 35 and about 
40, respectively, while Vistalon.RTM. 808 and 878 have Mooney viscosities 
(ML/1+4 at 125.degree. C.) of about 46 and 53, respectively. These 
ethylene-propylene copolymers are available in dense or semi-friable 
bales. 
Yet another suitable copolymer of propylene and ethylene is Pro-Fax SR549M 
produced by Montell. This resin has a peak melt temperature of 162.degree. 
C., a 11-15 melt index range, an izod range at 23.degree. C. from about 
1.5 to 2, and a specific gravity of about 0.95 g/cc at 23.degree. C. 
Other suitable copolymers include those saturated ethylene-octene 
copolymers which provide excellent weatherability and are available from 
Dow Plastics under the tradename Engage. For example, Engage.RTM. 8100 and 
Engage.RTM. 8200 have octene contents of about 24 and 25 weight percent, 
respectively. These general purpose elastomers have Mooney viscosities 
(ML/1+4 at 121.degree. C.) ranging from 23 to 35 and specific gravities of 
about 0.87 g/cc at 23.degree. C. 
Where these polyolefin resins and copolymers thereof are blended with the 
EPDM of the roof shingle composition, the polymer blend to be employed in 
the shingle composition generally includes major amounts of EPDM and only 
minor amounts of the impact modifying polymer(s). In fact, the polymer 
blend typically includes at least 100 parts by weight EPDM and up to about 
135 parts by weight of an impact modifying polymer, based upon the weight 
of the EPDM. While more than one impact modifying polymer may be used, the 
total amount of all these types of polymers combined should not exceed the 
amount of EPDM (including cryogenically or ambiently ground EPDM rubber 
and virgin EPDM used as the polymeric binder in the flame retardants and 
the like) provided. 
In addition to the EPDM terpolymers and the impact modifying polymers such 
as the polyolefin resins and copolymers thereof, as discussed hereinabove, 
the roofing shingle composition of the present invention may also include 
fillers, processing aids and curatives as well as other optional 
components including activators and flame retardant packages, all of which 
are discussed hereinbelow. The amounts of fillers, processing materials, 
curing agents, and other additives used in the roofing shingle composition 
will be expressed hereinafter as parts by weight per 100 parts by weight 
EPDM terpolymer, since EPDM is the base component of the roof shingle 
composition. Accordingly, where the term "phr" is used, it will be 
understood to mean parts by weight per 100 parts by weight virgin EPDM 
terpolymer, even if an additional impact modifying polymer is employed. 
With respect to the fillers, suitable fillers are selected from the group 
consisting of combustible and non-combustible materials. Generally, these 
materials can be added to the formulation in amounts ranging from about 25 
to about 525 parts by weight, per 100 parts virgin EPDM terpolymer. 
With respect to combustible materials, there are many types of materials 
which can be used as combustible fillers for the roofing shingle 
composition of the present invention. However, in the preferred 
embodiment, it is desired to keep the amount of combustible material as 
low as possible, and to particularly keep the amount of carbon black as 
low as possible. In this respect, it is preferred that no virgin carbon 
black be employed in the present invention. One particularly useful and 
preferred combustible material is cryogenically ground EPDM rubber. 
Essentially any cryogenically or ambiently ground EPDM rubber may be 
employed as a filler in the roofing shingle composition. Preferred 
cryogenically or ambiently ground rubbers are cryogenically or ambiently 
ground EPDM-based rubbers. The preferred ground EPDM rubber is a fine 
black rubbery powder having a specific gravity of about 1.16.+-.0.015 g/cc 
and a particle size ranging from about 30 to about 300 microns with an 
average particle size ranging from about 40 to about 80 microns. In the 
absence of any carbon black, the amount of cryogenically or ambiently 
ground rubber may be somewhat high, from about 0 to about 125 parts by 
weight per 100 parts virgin EPDM terpolymer (phr). It has been found that 
these ground rubbers provide significant reductions to the cost of the 
composition while maintaining the desired properties of the composition, 
since the ground rubber is essentially inert. 
Also particularly useful and preferred with respect to non-combustible 
materials are non-black mineral fillers. These mineral fillers are 
essentially inorganic materials which generally aid in reinforcement, heat 
aging resistance, green strength performance, and flame resistance. There 
are a number of different inorganic materials that fall into this category 
of fillers. For example, these mineral fillers include a number of 
different types of clays, including hard clays, soft clays, chemically 
modified clays, water-washed clays, and calcined clays. Other examples of 
mineral fillers suitable for use in the present invention include mica, 
talc, alumina trihydrate, antimony trioxide, calcium carbonate, titanium 
dioxide, silica, slate dust and certain mixtures thereof. Still other 
inorganics such as magnesium hydroxide and calcium borate ore may also be 
employed. In the preferred embodiment, these fillers completely replace 
"black" fillers, i.e. carbon black and other petroleum-derived materials. 
Generally, however, one or more of these mineral fillers are employed in 
amounts ranging from about 25 parts to about 400 parts by weight, per 100 
parts EPDM terpolymer. 
Any of four basic types of clays are normally used as fillers for rubber 
elastomers. The different types of clay fillers include airfloated, water 
washed, calcined and surface treated or chemically modified clays. 
The airfloated clays are the least expensive and most widely used. They are 
divided into two general groups, hard and soft, and offer a wide range of 
reinforcement and loading possibilities. Hard Clays may be used in the 
amount of about 20 parts to about 300 parts per 100 parts EPDM (phr), 
preferably in an amount from about 65 to 210 phr. Preferred airfloated 
hard clays are commercially available from J. M. Huber Corporation under 
the tradenames Barden R.RTM.; and LGBO from Kentucky-Tennessee Clay 
Company, Koalin Division, Sandersville, Ga., under the tradename 
Suprex.RTM.. 
The airfloated soft clays may be used in amounts ranging from about 20 
parts to about 300 parts per 100 parts of EPDM (phr), preferably in an 
amount from about 75 to 235 phr. The preferred airfloated soft clays are 
available from J. M. Huber Corporation under the tradename K-78.RTM., from 
Evans Clay Company under the tradename Hi-White Re and from 
Kentucky-Tennessee Clay Company, Koalin Division, Sandersville, Ga., under 
the tradename Paragon.RTM.. Particularly preferred is Hi-White R.RTM., an 
air-floated soft clay characterized as having a pH of about 6.25.+-.1.25, 
an oil absorption of 33 grams/100 grams of clay, a average particle size 
of less than two microns and a specific gravity of about 2.58 g/cc. 
Water washed clays are normally considered as semi-reinforcing fillers. 
This particular class of clays is more closely controlled for particle 
size by the water-fractionation process. This process permits the 
production of clays within controlled particle size ranges. The preferred 
amounts of water washed clays are very similar to the preferred amounts of 
airfloated soft clays mentioned hereinabove. Some of the preferred water 
washed clays include Polyfil.RTM. DL, Polyfil.RTM. F, Polyfil.RTM. FB, 
Polyfil.RTM. HG-90, Polyfil.RTM. K and Polyfil.RTM. XB; all commercially 
available from J. M. Huber Corporation. 
The third type of clay includes the calcined clay. Clays normally contain 
approximately 14 percent water of hydration, and most of this can be 
removed by calcination. The amount of bound water removed determines the 
degree of calcination. The preferred ranges of calcined clays are very 
similar to the preferred amounts of airfloated hard clays mentioned 
hereinabove. Some of the preferred calcined clays include Polyfil.RTM. 40, 
Polyfil.RTM. 70, and Polyfil.RTM. 80, all commercially available from J. M 
Huber Corporation. 
The last type of clay includes chemically modified reinforcing clays. 
Cross-linking ability is imparted to the clay by modifying the surface of 
the individual particles with a polyfunctional silane coupling agent. 
Chemically modified clays are used in the amount of from about 20 parts to 
about 300 parts per 100 parts EPDM (phr), preferably in an amount from 
about 60 to 175 phr. Normally, the specific gravity of most of these clays 
is about 2.60 at 25.degree. C. The preferred chemically modified clays are 
commercially available from J. M. Huber Corporation and include those 
available under the tradenames Nucap.RTM., Nulok.RTM. and Polyfil.RTM.. 
Other preferred chemically modified clays are commercially available from 
Kentucky-Tennessee Clay Company under the tradenames Mercap.RTM. 100 and 
Mercap.RTM. 200. 
As an alternative to the clays, a silicate may have utility in the present 
invention. For example, synthetic amorphous calcium silicates such as 
those which are commercially available from the J. M. Huber Company under 
the tradename Hubersorb.RTM. may be utilized. One particular silicate, 
Hubersorb.RTM. 600, is characterized as having an average particle size of 
3.2 micrometers (by the Coulter Counter Method), oil absorption of 450 
ml/100 grams of calcium silicate, a BET (BrunaverEmmet-Teller nitrogen 
adsorption procedure) surface area of 300 and a pH (5% solution) of about 
10. 
Other silicates which may be used in the composition of the present 
invention include precipitated, amorphous sodium aluminosilicate available 
from the J. M. Huber Company under the tradename Zeolex 23.RTM. has a BET 
surface area of about 75 m.sup.2 /gram, a refractive index at 20.degree. 
C. of about 1.51, and a pH of about 10.2 determined by slurring 20 grams 
of silicate with 80 grams of deionized water. In comparison, Zeolex.RTM. 
80 has a BET surface area of about 115 m.sup.2 /gram, a refractive index 
at 20.degree. C. of about 1.55, and a pH of about 7. The average particle 
size, density, physical form and oil absorption properties are similar to 
each other. 
Reinforcing silicas may also be used as non-combustible fillers, preferably 
in conjunction with one or more of the chemically modified clays noted 
hereinabove. Silica (silicon dioxide) utilizes the element silicon and 
combines it in a very stable way with two oxygen atoms. Generally, silicas 
are classed as wet-processed, hydrated silicas because they are produced 
by a chemical reaction in water, from which they are precipitated as 
ultrafine, spherical particles. However, there are in reality two 
different forms of silica, crystalline and amorphous (noncrystalline). The 
basic crystalline form of silica is quartz, although there are two other 
crystalline forms of silica that are less common--tridymite and 
cristobalite. On the other hand, the silicon and oxygen atoms can be 
arranged in an irregular form as can be identified by X-ray diffraction. 
This form of silica is classified as amorphous (noncrystalline), because 
there is no detectable crystalline silica as determined by X-ray 
diffraction. The most preferred forms of silica, i.e., a fine particle, 
hydrated amorphous silica, are available from PPG Industries, Inc. and J. 
M. Huber Corporation in a low dust granular form. these silicas typically 
are available from PPG Industries under the tradenames HiSil.RTM. and 
Silene.RTM.. Reinforcing silicas are generally characterized in terms of 
surface area (m.sup.2 /gram by the BET procedure) or particle size as 
determined by either electron microscopy or the Coulter Counter Method. 
These silicas can be employed in the amount of about 10 parts to about 110 
parts per 100 parts virgin EPDM terpolymer (phr), preferably in an amount 
from about 10 to 30 phr. The useful upper range is limited by the high 
viscosity imparted by fillers of this type. 
Still other fillers include calcium carbonate, titanium dioxide, talc 
(magnesium silicate), mica (mixtures of sodium and potassium aluminum 
silicate), alumina trihydrate, antimony trioxide, magnesium hydroxide, and 
calcium borate ore. The amount of these fillers may vary significantly 
depending upon the number and amount of other particular fillers employed, 
but typically are employed in amounts ranging from about 25 to about 250 
parts by weight, per 100 parts virgin EPDM terpolymer. The most preferred 
of these mineral fillers include 100 percent magnesium hydroxide (200 
parts or less), or mixtures of magnesium hydroxide (less than 100 parts) 
in combination with alumina trihydrate (less than 100 parts) and mistron 
vapor talc (less than 50 parts). Parts expressed as parts per 100 parts 
virgin EPDM terpolymer are by weight, unless otherwise indicated. 
One particularly useful form of talc is Mistron Vapor Talc (MVT) 
commercially available from Luzenac America, Inc. Mistron Vapor Talc (MVT) 
is a soft, ultra-fine, white platy powder having a specific gravity of 
2.75 g/cc. Chemically, Mistron Vapor Talc is ground magnesium silicate 
having a median particles size of 1.7 microns, an average surface area of 
about 18 m.sup.2 /gram and a bulk density (tapped) of 20 lbs/ft.sup.3. 
Alumina trihydrate is a finely divided, odorless, crystalline, white powder 
having the chemical formula Al.sub.2 O.sub.3. 3H.sub.2 O. Alumina 
trihydrate is utilized in the present invention to enhance the green 
strength of the EPDM terpolymer or the other polyolefins. Preferably, 
alumina trihydrate has an average particle size ranging from about 0.1 
micron to about 5 microns, and more preferably, from about 0.5 micron to 
about 2.5 microns. 
A preferred ground alumina trihydrate for use with the invention is 
designated H-15 (ATH-15), and has a specific gravity of about 2.42 g/cc, 
and an ash content of about 64-65 weight percent. ATH-15 is commercially 
available from Franklin Industrial Minerals, of Dalton, Ga. Other alumina 
trihydrates produced by Franklin Industrial Minerals which are believed to 
have utility in this invention include those designated H-100, H-105, 
H-109 and H-990. Alumina trihydrate can also be advantageously used as a 
flame retardant and smoke suppressant in the EPDM-based roof shingle 
composition of the present invention. 
Other sources of alumina trihydrates are Micral 1000 and Micral 1500, 
available from J. M. Huber Corporation, Engineered Minerals Division, of 
Norcross, Ga., which have a median particle size of about 1.1 microns and 
1.5 microns, respectively. Both alumina trihydrates have a specific 
gravity of about 2.42 g/cc, an ash content of about 64-65 weight percent 
and a loss on ignition (LOI) at 1000.degree. F. of about 34.65 weight 
percent. Other alumina trihydrates produced by this corporation which are 
believed to have utility in this invention include those designated as 
Micral 932 and Micral 532 as well as superfme alumina trihydrates 
including SB-632 and SB-805. 
Another particularly useful mineral filler is the ore of calcium borate. 
This filler is available in various particle size grades from American 
Borate Company, Virginia Beach, Va., under the tradename Colemanite.RTM. 
and has the chemical formula Ca.sub.2 B.sub.6 O.sub.11. 5H.sub.2 O. 
Colemanite has a specific gravity of about 2.4 g/cc. This ore has an 
average particle size of about 0.1 to about 5 microns, and more 
preferably, from about 0.5 micron to about 2.5 microns. 
Still another mineral filler which may be particularly suitable for use in 
the roofing shingle composition of the present invention is magnesium 
hydroxide. Magnesium hydroxide (Mg(OH).sub.2)is a finely divided, white 
powder which is an extremely effective smoke suppressant as well as a 
flame retardant additive. It is well documented that (Mg(OH).sub.2) is 
highly effective in reducing smoke. Thus, this mineral filler is believed 
to be particularly useful where smoke and fire resistivity is a concern. 
To that end, this mineral filler often times will replace other mineral 
fillers such as silica or some of the clays in the roof shingle 
composition. 
Commercial grades of magnesium hydroxide are available from Martin Marietta 
Magnesia Specialties, Inc. under the tradename MagShield. MagShield S is a 
magnesium hydroxide with a mean particle size of about 6.9 microns. 
MagShield M has a mean size of about 1.9 microns. Both of these grades of 
magnesium hydroxide are about 98.5 percent pure, have about 0.3 percent 
loss on drying and about 30.9 percent by weight loss on ignition, and a 
specific gravity of about 2.38 g/cc at 23.degree. C. 
Clay, titanium dioxide, alumina trihydrate, magnesium hydroxide, talc and 
mica can also be used to develop a gray colored or slate-like colored 
roofing shingle. The desirable gray color may be obtained through the use 
of different combinations of non-combustible mineral fillers. 
The present invention may further utilize up to about 150 parts by weight, 
per 100 parts EPDM terpolymer, ground EPDM-based rubber dust (20 mesh) in 
developing uniquely colored EPDM-based roofing shingle compositions. It 
will be appreciated that, by the term "uniquely colored", it is meant that 
the compositions are of a color other than those colors commonly 
associated with shingles, i.e., dark gray or black. Such slate-colored or 
dark gray shingle compositions have been referred to as "normal colored" 
shingle compositions. The finely ground EPDM-based rubber dust is 
available in various colors, i.e., green, red, purple, tan, blue, orange, 
etc. The EPDM polymer content on the ground rubber dust was found to be 
about 20 weight percent according to thermal analysis data. The specific 
gravity of the colored rubber dust was determined to be 1.568 g/cc. The 
colored rubber dust has been screened to 20 mesh, packaged in 23 kg 
polybags and is commercially available from Goldsmith & Eggleton, 
Wadsworth, Ohio 44281. 
The roofing shingle composition of the present invention may also contain 
one or more processing materials. Processing materials are generally 
included to improve the processing behavior of the roof shingle 
composition (i. e. to reduce mixing time and to increase the rate of 
compound throughout) and includes processing oils, waxes and other similar 
additives. A process oil may be included in an amount ranging from about 
20 parts to about 75 parts process oil per 100 parts EPDM terpolymer 
(phr), preferably in an amount ranging from about 40 phr to about 60 phr. 
A preferred processing oil is a parafrmic oil, e.g. Sunpar 2280, which is 
available from the Sun Oil Company. Also, Hyprene P150BS from Ergon, Inc., 
has utility in this invention. Other petroleum derived oils including 
naphthenic oils are also usefiul. Liquid halogenated paraffms may serve as 
softeners or extenders and are also often desirable as flame retardant 
additives. 
A preferred liquid chlorinated paraffin is Doverguard 5761, which features 
about 59 weight percent chlorine and can be used both as a softener as 
well as a fire retardant additive. This liquid paraffin has a viscosity of 
about 20 poise at 25.degree. C. and a specific gravity of about 1.335 
gm/cc at 23.degree. C. Another liquid paraffin having utility in this 
invention is a liquid bromochlorinated paraffin flame retardant additive, 
i.e., Doverguard 8207A having 30 and 29 weight percent bromine and 
chlorine, respectively. Doverguard 8207A has a specific gravity of about 
1.42 gm/cc at 50.degree. C. Both liquid halogenated paraffms are 
commercially available from Dover Chemical Corporation, a subsidiary of 
ICC Industries, Inc. 
A homogenizing agent may also be added, generally in an amount of less than 
10 parts by weight, more preferably, in an amount of about 2 to 5 parts by 
weight, and most preferably 2.5 parts by weight, per 100 parts EPDM 
terpolymer. One particularly suitable homogenizing agent is available in 
both flake and pastille form from Struktol Company under the tradename 
Struktol 40 MS. The preferred homogenizing agent is composed of a mixture 
of dark brown aromatic hydrocarbon resins having a specific gravity of 
about 1.06 g/cc at 23.degree. C. 
A fire retardant package may also be added to the composition where 
increased fire resistance is desired. There are a variety of fire 
retardant packages commercially available for use with rubber 
compositions. Generally, the flame retardant system incorporated in the 
roof shingle composition can be made of different types of materials 
including ratios of decabromodiphenyl oxide (DBDPO) or related bromine 
containing additives and antimony trioxide. Various inorganic materials, 
clay, alumina trihydrate, magnesium hydroxide, silica, mica, talc and zinc 
carbonate can be used as part of the filler system as well as flame 
retardant additives. Certain halogenated paraffins can be used as the 
softener or extender and still impart flame resistance to the roof shingle 
composition. 
One particularly useful fire retardant package is available from Great 
Lakes Chemical Corporation. This fire retardant package is 85 percent 
active and contains 15 percent by weight EPDM terpolymer as a polymeric 
binder for the package. The package also includes a mixture of antimony 
trioxide and decabromodiphenyl oxide. Another useful fire retardant 
package is also available from Great Lakes Chemical Corporation, and is 
82.5 percent active. The fire retardant package contains 17.5 percent by 
weight EPDM as the polymeric binder. Zinc borate, decabromodiphenyl oxide 
and antimony trioxide are further included in the package. It will be 
appreciated that, where used, these packages are employed in amounts 
ranging from about 40 to 70 parts by weight, per 100 parts EPDM. As 
discussed hereinabove, it will also be appreciated that these fire 
retardant packages may contain a portion of the virgin EPDM terpolymer 
employed in the roof shingle composition. The above fire retardant 
packages were formerly produced by Anzon Chemical Company. 
The present invention may also include reinforcing fibers to increase the 
stiffness of the cured EPDM-based roofing shingle composition. Preferably, 
these reinforcing fibers are chopped fibers or filaments selected from the 
group consisting of fiberglass, polyester, polyamide, polyolefin and 
mixtures thereof. Fiberglass fibers appear to be the most preferred for 
the particular roofing shingles of the present invention. When used, 
amounts up to about 20 parts by weight per 100 parts EPDM are preferred. 
In a preferred embodiment, reinforcing glass fibers are about 4 
millimeters in chop length and have a filament diameter of about 14 
microns. Any chopped fibers of about 12 millimeters in length or less are 
preferred, however. Moreover, other synthetic fibers, e.g., polyester, 
nylon, rayon, and Kevlar (aramid) can be used in this invention, however 
glass fiber is preferred. Fibers with a filament diameter of about 25 
microns or less are preferred in this invention. Often times, 
rubber-to-fiber adhesion can be improved by chemically treating the 
surface of the individual fibers. The samples of chop glass fiber 
evaluated in this invention are commercially available from Owens Corning, 
and have been found to uniformly disburse well in the composition. 
The roofing shingle composition may also include a cure package containing 
sulfur and at least one sulfur vulcanizing accelerator in order to effect 
full cross-linking or vulcanizing of the composition prior to its use on a 
roof. The composition is typically vulcanized for a period of time at an 
elevated temperature to insure sulfur crosslinking. The polymeric 
composition may be cured using any of several well-known curing agents, 
but preferably the cure package of the present invention includes sulfur 
and one or more sulfur vulcanizing accelerators. 
Generally, the sulfur/accelerator cure package employed in the roof shingle 
composition of the present invention is provided in amounts ranging from 
about 1.5 to about 10 phr, depending upon the amount of sulfur utilized. 
As noted, the sulfur and sulfur-containing cure systems used in the present 
invention typically include one or more sulfur vulcanizing accelerators. 
Suitable accelerators commonly employed include, for example, thioureas 
such as ethylene thiourea, N,N-dibutylthiourea, N,N-diethylthiourea and 
the like; thiuran monosulfides and disulfides such as tetramethylthiuram 
monosulfide (TMTMS), tetrabutylthiuram disulfide (TBTDS), 
tetramethylthiuram disulfide (TMTDIS), tetraethylthiuram monosulfide 
(TETMS), dipentamethylenethiuram hexasulfide (DPTH) and the like; 
benzothiazole sulfenamides such as N-oxydiethylene-2-benzothiazole 
sulfenamide, Ncyclohexyl-2-benzothiazole sulfenamide, 
N,N-diisopropyl-2-benzothiazole sulfenamide, N-tert-butyl-2-benzothiazole 
sulfenamide (TBBS) and the like; other thiazole accelerators such as 
Captax (MBT) or Altax (MBTS), 2-mercaptoimidazoline, 
N,N-diphenylguanadine, N,N-di-(2-methylphenyl)-guanadine, 
2-mercaptobenzothiazole, 2-(morpholinodithio)benzothiazole disulfide, zinc 
2-mercaptobenzothiazole and the like; dithiocarbamates such as tellurium 
diethyldithiocarbamate, copper dimethyldithiocarbamate, bismuth 
dimethyldithiocarbamate, cadmium diethyldithiocarbamate, lead 
dimethyldithiocarbamate, zinc diethyldithiocarbamate, zinc 
dimethyldithiocarbamate and zinc dibutyldithiocarbamate (ZDBDC). In a 
preferred embodiment, the sulfur cure package comprises sulfur and two 
sulfur vulcanizing accelerators, namely MBTS and ZDBDC. 
It should be appreciated that the foregoing list is not exclusive, and that 
other vulcanizing agents known in the art to be effective in the curing of 
EPDM terpolymers employed in the polymer blend may also be utilized. For a 
list of additional vulcanizing agents, see The Vanderbilt Rubber Handbook, 
RT Vanderbilt Co., Norwalk Conn. 06855 (1990). It should also be 
understood that these sulfur donor-type accelerators may be used in place 
of the elemental sulfur or in conjunction therewith. Suitable amounts of 
sulfur to be used in the cure package can be readily determined by those 
skilled in the art, and generally range from about 0.25 to 2.0 phr, while 
the amount of sulfur vulcanizing accelerator can also be readily 
determined by those skilled in the art and generally range from about 1.5 
to about 10 phr, depending upon the amount of sulfur, the type of 
vulcanizing accelerators selected and the ultimate destination or use of 
the EPDM-based roofing shingle composition. 
It will be appreciated that the sulfur and the sulfur vulcanizing 
accelerators may be added in amounts suitable for curing the roofing 
shingle compositions after it has been installed on the rooftop. Thus, 
when employed as a rooftop curable roofing shingle in a warm climate, 
different accelerators and/or amounts thereof, known to those skilled in 
the art, can be selected as compared to those accelerators to be used for 
rooftop curing in cooler climates. 
In order to be rooftop curable, the roofing shingle composition is not 
fully cured prior to application and need not be cured subsequent thereto. 
The presence of the cure package allows the roofing shingle composition to 
cure at temperatures of at least about 50.degree. C., readily obtainable 
when exposed to sunlight in most climates. 
Accelerators generally require a metal oxide, i.e., zinc oxide for cure 
activation in most all types of rubbers. Zinc oxide is almost always the 
metal oxide of choice because of its effectiveness and lack of toxicity. 
The amount of zinc oxide may vary, but about 1 to about 10 parts, 
preferably 4 to 5 parts by weight per 100 part of EPDM terpolymer, in the 
formulation have been found to give the desired effect. Also, in order to 
initiate the vulcanization process, from about 1 to 2 parts of stearic 
acid by weight, per 100 parts of the EPDM terpolymer is present in the 
shingle composition. Using heat, both zinc oxide and stearic acid act as 
cure activators in the presence of sulfur, one or more sulfur vulcanizing 
accelerators and unsaturated EPDM polymer to help promote the formation of 
sulfur crosslinks during the vulcanization process. Some of the initial 
chemical reactions which take place during the early stages of the 
vulcanization process include reacting zinc oxide with stearic acid to 
form salts of even greater vulcanization activity. Zinc oxide itself acts 
as a cure activator or vulcanization promoter, speeding the rate of 
reaction of elemental sulfur with the unsaturation in the diene portion of 
the EPDM terpolymer. In addition to its use as a curing component, the 
sulfur component of the present invention may also be used in conjunction 
with zinc oxide to improve heat aging resistance of the roof shingle 
composition. 
During the molding process, vulcanization temperatures as high as 
210.degree. C. are generally adequate to complete vulcanization in about 1 
to 7 minutes. The vulcanization time can be further reduced by elevating 
the molding temperature during the vulcanization process. Roof shingles 
may be produced using either the compression or injection molding process. 
Other ingredients may also be included in the roof shingle composition. For 
example, additional conventional rubber compounding additives such as 
antioxidants, antiozonants and the like may be included in conventional 
amounts typically ranging from about 0.50 to about 4 phr. 
The compounding ingredients can be preferably admixed or compounded in a 
Brabenderg mixer or a type B internal mixer (such as a Banbury mixer), or 
any other mixer suitable for preparing viscous relatively uniform 
admixtures. When utilizing a type B Banbury internal mixer or a 
Brabender.RTM. mixer, in a preferred mode, the dry or powdery materials 
(e.g., carbon black, mineral filler, zinc oxide, stearic acid, fire 
retardant additives, etc.) are added into the mixing cavity first, 
followed by any liquid process oil or softeners (e.g., process oil, 
plasticizers, etc.) and fmally, the polymeric components (e.g., EPDM, EPM, 
LDPE, HDPE, IPP, etc.) This type of mixing can be referred to as an 
upside-down mixing technique. The mixing time may vary from about 2.5 
minutes to 5-6 minutes, depending on the melt characteristics of the 
polyethylene and polypropylene resins. The drop or dump temperature of the 
first-stage mix (masterbatch) is usually about 163.degree. C. to 
185.degree. C. The masterbatch is refined and resheeted on a hot two-roll 
mix. The temperature of the mill rolls usually ranges from about 
150.degree. C. to about 170.degree. C. 
Within a matter of minutes, the resheeted slab stock is cut to the desired 
dimensions and added strip by strip to the cavity of the mixing chamber. 
After about 50 percent of the rubbery masterbatch has been added to the 
mixer, the cure package is discharged into the mixing chamber followed by 
the addition of the remainder of the masterbatch. The temperature of the 
rubbery mix is allowed to reach temperatures as high at about 300.degree. 
F. (150.degree. C.) for only a very short period of time (approximately 
1.5 minutes or less). The second stage mix (final) is quickly resheeted to 
the desired dimensions again using a hot two-roll mill. The total mixing 
time involving the second stage mix (final) is usually no more than about 
two minutes. The freshly prepared fully compounded test specimens are 
press cured about 30 minutes at 320.degree. F. (160.degree. C.). Typical 
test properties performed include those tests which indicate stress-strain 
properties, tear resistance, ozone aging resistance, weathering 
resistance, Shore "A" hardness, water absorption, heat aging resistance 
and oxygen index measurements. 
In order to demonstrate the practice of the present invention, several 
roofing shingle compositions prepared according to the concepts of the 
present invention were compounded in a Brabender.RTM. mixer using the 
above-described two-stage mixing technique. The dry or powdery materials 
(e.g., carbon black, mineral filler, zinc oxide, stearic acid, fire 
retardant additives, etc.) were charged into the mixing cavity first. 
Next, any process oil or softeners, e.g., process oil, plasticizers, etc., 
were added. Lastly, the elastomeric components, e.g., EPDM, EPM, LDPE, 
LLDPE, HDPE, IPP, etc.) were added to the cavity of the mixer. 
The following examples are submitted for further illustrating the nature of 
the present invention and are not to be considered as a limitation of the 
scope thereof. Parts and percentages are by weight, unless otherwise 
indicated. The composition of each of the roofing shingle formulations 
prepared are shown in Tables I-III hereinbelow. 
Table I is a comparison of virgin EPDM-based roof shingle compositions 
(control) and recycled EPDM-based roofing shingle material prepared from a 
composition of matter comprising: a polymer component, mineral fillers, 
processing aids, processing oil, cure activators, and other compounding 
additives. A sulfur/accelerator cure package was added to each roof 
shingle composition. While Compound No. 1 comprised 100 percent virgin 
EPDM terpolymer as the polymer component, Compound No. 2 comprised 100 
percent recycled EPDM-based roof shingle compound which also featured 100 
parts EPDM and 100 parts cryogenically ground EPDM (40 mesh) material, 
including uncured roof shingle edge trimmnings and cured flash trimmed 
from the edges of cured compression molded EPDM-based roofing shingles. 
The purpose of this compounding study was to determine if a recycled roof 
shingle compound (Compound No. 2) can be used to produce EPDM-based roof 
shingles which will have physical properties comparable to the compound 
(Compound No. 1) which contains EPDM polymer that has not been recycled. 
To the 100 parts of EPDM terpolymer of Compound Nos. 1 and 2, 150 parts by 
weight magnesium hydroxide, 50 parts by weight mica 150, 2.5 parts by 
weight processing aid, 135 parts by weight high density polyethylene, 100 
parts by weight EPDM cryogrind (40 mesh), 50 parts by weight process oil, 
7.5 parts by weight titanium dioxide, 4.0 parts by weight zinc oxide and 
1.25 parts by weight stearic acid, was added to create a masterbatch. A 
sulfur/accelerator cure package comprising 1.0 part by weight of sulfur, 
2.15 parts by weight of benzothiazyl disulfide (MBTS) accelerator and 1.40 
parts by weight of zinc dibutyldithiocarbamate (ZDBDC). Each of the 
compounds were prepared utilizing standard polymer mixing techniques and 
equipment by mixing together the ingredients listed hereinabove. 
In order to evaluate and compare the properties of the EPDM-based roofing 
shingles comprising either virgin Royalene EPDM (Compound No. 1) or 
uncured edge trimmings and cured flash trimmed from the edges of 
compression molded roof shingles (Compound No. 2) were prepared by 
compounding the EPDM terpolymers, thermoplastic modifying polymers, 
fillers, process oil and other additives in a type B Banbury internal 
mixer and resheeted using a hot two-roll mill as described hereinabove. 
The sulfur/accelerator cure package was added to the masterbatch in the 
Banbury mixer and again resheeted to the proper dimensions on a hot 
two-roll mill. The results of the various properties tested, including 
scorch time, time to 50% and 90% cure, compound viscosity, stress-strain 
properties, die-C tear resistance and Shore "A" hardness are reported in 
Table I. 
TABLE I 
______________________________________ 
Effect of Recycling on the Physical Property Performance of 
Roof Shingle Compositions 
COMPOUND NOS. 
1 2 
(Virgin Compound) (Recycled Compound) 
______________________________________ 
Royalene EPDM 100 100 
Magnesium Hydroxide 150 150 
Mica 50 50 
Processing Aid 2.5 2.5 
HDPE 135 135 
EPDM Cryogrind 100 100 
(40 Mesh) 
Paraffinic Process Oil 50 50 
Titanium Dioxide 7.5 7.5 
Zinc Oxide (cure activator) 4.0 4.0 
Stearic Acid 1.25 1.25 
Masterbatch 600.25 600.25 
Cure Package 
Sulfur 1.0 1.0 
MBTS accelerator 2.15 2.15 
ZDBDC accelerator 1.40 1.40 
TOTAL 604.80 604.80 
Rheometer at 320.degree. F. (160.degree. C.) - mini-die, 3.degree. arc 
Scorch time, minutes 
4:53 3:31 
Time to 50% cure, minutes 7:18 5:17 
Time to 90% cure, minutes 13:50 12:18 
Minimum torque, lb.-inch 9.2 10.6 
Maximum torque, lb.-inch 21.2 23.7 
Mooney Scorch at 275.degree. F. (135.degree. C.) - large rotor 
Minimum Viscosity, Mu 
44.5 46.4 
T.sub.5, minutes 18.3 15.7 
T.sub.35, minutes 33.7 32.3 
Stress-Strain Properties at 73.degree. F. (23.degree. C.) 
Unaged 
100% Modulus, psi 
525 705 
300% Modulus, psi 685 816 
Tensile at break, psi 1000 930 
Elongation at break, % 565 495 
Heat Aged for 28 Days at 240.degree. F. (116.degree. C.) 
100% Modulus, psi 
855 1050 
300% Modulus, psi 1210 1315 
Tensile at break, psi 1318 1325 
Elongation at break, % 365 305 
Die C Tear Properties at 73.degree. F. (23.degree. C.) 
Unaged 
Lbs/inch 267 288 
Heat Aged for 28 Days at 240.degree. F. (116.degree. C.) 
Lbs/inch 289 304 
Shore "A" Hardness 
Unaged-Tested at 73.degree. F. 
88 90 
(23.degree. C.) 
Heat Aged for 28 Days at 89 91 
240.degree. F. (116.degree. C.) 
______________________________________ 
The cure characteristics of the virgin and recycled EPDM-based roofing 
shingle compositions were determined by means of a Monsanto Oscillating 
Disc Rheometer (described in detail in American Society of Testing and 
Materials Standard, ASTM D-2084). The metal die used to measure the scorch 
time, cure rates and state of cure is referred to as a mini-die. During 
testing, the die oscillated at a 3.degree. arc. According to the rheometer 
data shown in Table I, the recycled roof shingle composition (Compound No. 
2) was directionally faster curing, relative to the virgin roof shingle 
composition. Both roof shingle compositions had similar cure states based 
on maximum torque results. 
The test method (ASTM D 1646) covers the use of the shearing disc 
viscometer for measuring the Mooney Viscosity of raw polymers and fully 
compounded rubber composition. The viscosity of the fully compounded 
rubber compound during vulcanization can be detected with this instrument 
as evidenced by an increase in viscosity. Therefore, this test method can 
be used to determine incipient cure time and the rate of cure during very 
early stages of vulcanization. Based on Mooney Scorch data at 135.degree. 
C., Compound Nos. 1 and 2 have similar compound viscosities and the 
compound featuring the recycled EPDM-based material was slightly faster 
curing based on time to five point rise. Based on Mooney Scorch at 
135.degree. C. data, the recycled roof shingle composition was 
characterized as a higher viscosity, slightly faster curing compound 
compared to the virgin roof shingle composition (Compound No. 1). 
For testing stress-strain properties at 23.degree. C., dumbbell-shaped 
specimens were cut using the appropriate metal die from individual cured 
45 mil six by six-inch flat rubber slabs (compression molded 30 minutes at 
160.degree. C.) in accordance with ASTM D 412 (Method A--dumbbell and 
straight). Modulus (psi), tensile strength at break (psi) and elongation 
at break (%) measurements were obtained on unaged dumbbell-shaped test 
specimens using a table model Instron.RTM. Tester, Model 4301, and the 
test results were calculated in accordance with ASTM D 412. The 
Instron.RTM. Tester (a testing machine of the constant rate-of-jaw 
separation type) is equipped with suitable grips capable of clamping the 
test specimens without slippage. Unaged samples and samples heat aged for 
28 days at 116.degree. C. involving Compound Nos. 1 and 2 were tested. All 
dumbbell-shaped test specimens were allowed to set for about 24 hours, 
before testing at 20 inches per minute crosshead speed at 23.degree. C. 
According to the stress-strain property data shown in Table I, the unaged 
sample of Compound No. 1 (virgin compound) has a 100% modulus (psi) of 
525, a 300% modulus (psi) of 685, a tensile strength at break (psi) of 
1000 and an elongation at break (%) of 565. The unaged sample of Compound 
No. 2 (featuring 100% recycled roof shingle compound) has a 100% modulus 
(psi) of 705, a 300% modulus (psi) of 816, a tensile strength at break 
(psi) of 930 and an elongation at break (%) of 495. The unaged 
stress-strain properties in Table 1 revealed that Compound Nos. 1 and 2 
have similar stress-strain properties as measured at 23.degree. C. 
Heat aged samples of Compound Nos. 1 and 2 were also tested for their 
stress-strain properties at 23.degree. C. According to the stress-strain 
property data shown in Table I, the heat aged sample of Compound No. 1 
(virgin compound) has a 100% modulus (psi) of 855, a 300% modulus (psi) of 
1210, a tensile strength at break (psi) of 1318 and an elongation at break 
(%) of 365. The heat aged sample of Compound No. 2 (featuring 100% 
recycled roof shingle compound) has a 100% modulus (psi) of 1050, a 300% 
modulus (psi) of 1315, a tensile at break (psi) of 1325 and an elongation 
at break (%) of 305. As shown from the data in Table I, the heat aged 
samples of Compound Nos. 1 and 2 have similar stress-strain properties as 
measured at 23.degree. C. 
Die C tear properties for unaged samples and samples heat aged for 28 days 
at 116.degree. C. involving Compound Nos. 1 and 2 were determined by using 
a metal die (90.degree. angle die C) to remove the test specimens from 
cured 45 mil six by six-inch flat rubber slabs (compression molded 30 
minutes at 160.degree. C.) in accordance with ASTM D 624. All die C tear 
test specimens, were allowed to set for about 24 hours, before testing was 
carried out at 23.degree. C., as shown in Table I. 
Tear properties, in lbs./inch, were obtained using a table model 
Instron.RTM. Tester, Model 4301 and the test results were calculated in 
accordance with ASTM Method D 624. As shown in Table I, unaged and heat 
aged samples of Compound Nos. 1 and 2 have similar die C tear properties. 
Shore "A" hardness, which measures the hardness of the cured roofing 
shingle compound, was conducted at 23.degree. C. in accordance with ASTM 
Method D 2240 for unaged and heat aged samples of Compound Nos. 1 and 2. 
The cured test specimens were allowed to set for about 24 hours prior to 
testing. As shown in Table I, unaged and heat aged samples of Compound 
Nos. 1 and 2 have very similar Shore "A" hardness values. 
As can be seen from the data presented in Table I, the virgin compound and 
the compound prepared from 100% recycled EPDM-based roof shingle 
compositions, (Compound Nos. 1 and 2) exhibited similar stress-strain, die 
C tear and Shore "A" hardness properties both before and after heat aging 
28 days at 116.degree. C. 
Based on the foregoing results in Table I with respect to cure 
characteristics, Mooney viscosity, stress-strain properties, die C tear 
properties and Shore "A" hardness properties, both the virgin EPDM-based 
compound and the 100% recycled EPDM-based roofing shingle compositions are 
suitable for the manufacture of roofing shingles used to cover high 
durometer sloped roofs. 
Compound Nos. 3-6 in Table II provide examples of sulfur curable, colored, 
high durometer EPDM-based roofing shingle compositions of the present 
invention, and are submitted for the purpose of further illustrating the 
nature of the present invention. 
TABLE II 
______________________________________ 
Properties of Colored EPDM-Based Roof Shingle Compositions 
COMPOUND NOS. 
3 4 5 6 
______________________________________ 
Royalene EPDM 100 100 100 100 
Magnesium Hydroxide 150 150 150 150 
Mica 50 50 50 50 
Processing Aid 2.50 2.50 2.50 2.50 
HDPE 135 135 135 135 
EPDM Cryogrind (40 mesh) 100 -- -- -- 
EPDM Cryogrind (20 mesh) -- 100 -- -- 
(red rubber dust) 
EPDM Cryogrind (20 mesh) -- -- 100 -- 
(green rubber dust) 
EPDM Cryogrind (20 mesh) -- -- -- 100 
(tan rubber dust) 
Paraffinic Process Oil 50 50 50 50 
Titanium Dioxide 7.50 7.50 7.50 7.50 
Zinc Oxide (cure activator) 4.0 4.0 4.0 4.0 
Stearic Acid 1.25 1.25 1.25 1.25 
Masterbatch 600.25 600.25 600.25 600.25 
Cure Package 
Sulfur 1.0 1.0 1.0 1.0 
MBTS accelerator 2.15 2.15 2.15 2.15 
ZDBDC accelerator 1.40 1.40 1.40 1.40 
TOTAL 604.80 604.80 604.80 604.80 
Rheometer at 320.degree. F. (160.degree. C.) - mini-die 3.degree. arc 
Scorch time, minutes 
4:53 5:05 4:39 4:56 
Time to 50% cure, minutes 7:18 7:29 6:53 7:11 
Time to 90% cure, minutes 13:50 13:43 12:57 13:36 
Minimum torque, lb.-inch 9.2 8.7 9.1 9.0 
Maximum torque, lb.-inch 21.2 19.9 20.8 20.7 
Mooney Scorch at 275.degree. F. (135.degree. C.) - large rotor 
Minimum Viscosity, Mu 
44.5 42.9 45.7 45.1 
T.sub.5, minutes 18.3 17.8 17.5 18.7 
T.sub.35, minutes 33.7 32.8 33.1 34.3 
Stress-Strain Properties at 73.degree. F. (23.degree. C.) 
Unaged 
100% Modulus, psi 525 845 885 865 
300% Modulus, psi 685 990 1080 1025 
Tensile at break, psi 1000 1305 1465 1440 
Elongation at break, % 565 512 520 550 
Heat Aged for 28 Days at 240.degree. F. (116.degree. C.) 
100% Modulus, psi 855 1180 1130 1160 
300% Modulus, psi 1210 1860 1605 1750 
Tensile at break, psi 1318 1999 1850 1788 
Elongation at break, % 365 327 363 301 
Die C Tear Properties at 73.degree. F. (23.degree. C.) 
Unaged 
Lbs/inch 267 334 325 342 
Heat Aged for 28 Days at 240.degree. F. (116.degree. C.) 
Lbs/inch 289 316 318 314 
Shore "A" Hardness 
Unaged-Tested at 73.degree. F. (23.degree. C.) 
88 90 91 90 
Heat Aged for 28 Days at 240.degree. F. 89 92 92 91 
(116.degree. C.) 
______________________________________ 
The examples illustrated in Table II (Compound Nos. 3-6) are sulfur 
curable, colored, EPDM-based roofing shingle compositions prepared from a 
composition of matter comprising: a polymer component, a thermoplastic 
modifying polymer, a colored EPDM rubber dust, mineral fillers, processing 
aid, processing oil, cure activator and other additives. A 
sulfur/accelerator cure package was added to the roofing shingle 
compositions of Table II. Compound Nos. 3-6 comprise a Royalene EPDM 
terpolymer as the polymer component of the roofing shingle composition. To 
the 100 parts of EPDM terpolymer of Compound Nos. 3-6, 150 parts by weight 
magnesium hydroxide, 50 parts by weight mica, 2.5 parts by weight 
processing aid, 135 parts by weight high density polyethylene, 50 parts by 
weight paraffinic process oil, 7.5 parts by weight titanium dioxide, 4.0 
parts by weight zinc oxide and 1.25 parts by weight stearic acid. To 
Compound No. 3, 100 parts by weight EPDM cryogrind (40 mesh), per 100 
parts of EPDM terpolymer was added to create the masterbatch. To Compound 
No. 4, 100 parts by weight EPDM cryogenically ground (20 mesh) red rubber 
dust, per 100 parts EPDM terpolymer was added to create the masterbatch. 
To Compound No. 5, 100 parts by weight EPDM cryogenically ground (20 mesh) 
green rubber dust, per 100 parts EPDM terpolymer was added to create the 
masterbatch. To Compound No. 6, 100 parts by weight EPDM cryogrind (20 
mesh) tan rubber dust, per 100 parts of EPDM terpolymer was added to 
create the masterbatch. A sulfur/accelerator cure package comprising 1 
part by weight sulfur, 2.15 parts by weight benzothiazyl disulfide (MBTS) 
accelerator and 1.40 parts by weight zinc dibutyldithiocarbamate (ZDBDC) 
were added to each of Compound Nos. 3-6. Each of the compounds were 
prepared utilizing standard rubber mixing techniques and equipment by 
mixing together the ingredients listed hereinabove. 
In order to evaluate the properties of the colored, high durometer, 
EPDM-based roofing shingle compositions comprising Royalene EPDM 
terpolymer, Compound Nos. 3-6 were prepared by compounding the EPDM 
terpolymer, thermoplastic modifying polymers, EPDM colored rubber dust, 
mineral fillers, process oil and other additives in a type B Banbury 
internal mixer and resheeted on a hot tworoll mill as described 
hereinabove. The sulfur/accelerator package was added to the masterbatch 
in the Banbury mixer and again resheeted to the proper dimensions using a 
hot two-roll mill. The results of the various properties tested, including 
scorch time, time to cure, compound viscosity, stress-strain properties, 
die-C tear resistance and Shore "A" hardness are reported in Table II. 
The cure characteristics of the control normal colored, i.e., dark gray or 
"slate-like" colored, and the uniquely colored EPDM-based roofing shingles 
were determined by means of a Monsanto Oscillating Disc Rheometer 
(described in detail in American Society of Testing and Materials 
Standard, ASTM D-2084). The metal die used to measure the scorch time, 
cure rates and state of cure is referred to as a mini-die. During actual 
testing, the die oscillated at a 3.degree. arc according to the rheometer 
data shown in Table II. Differences in scorch time (time to two point 
rise), cure time and state of cure between the normal colored roof shingle 
(Compound No. 3) and uniquely colored roof shingle compositions featuring 
red, green and tan colored rubber dust (20 mesh) were minimal. 
The test method (ASTM D 1646) covers the use of the shearing disc 
viscometer for measuring the Mooney Viscosity of raw polymers and fully 
compounded rubber composition. The viscosity of the fully compounded 
rubber composition during vulcanization can be detected with this 
instrument as evidenced by an increase in compound viscosity. Therefore, 
this test method can be used to determine incipient cure time and the rate 
of cure during very early stages of vulcanization. Based on Mooney Scorch 
data at 135.degree. C., Compound Nos. 3-6 have similar viscosities and 
curing times. Based on the Mooney Scorch at 135.degree. C., the colored 
rubber dust had essentially no influence on the compound viscosity and 
cure rate of the uniquely colored roof shingle compositions, relative to 
the normal colored roof shingle composition (Compound No. 3). 
For testing stress-strain properties at 23.degree. C., dumbbell-shaped test 
specimens were cut using the appropriate metal die from individual cured 
45 mil six by six-inch flat rubber slabs (compression molded 30 minutes at 
160.degree. C.) in accordance with ASTM D 412 (Method A--dumbbell and 
straight). Modulus (psi) tensile strength at break (psi) and elongation at 
break (%) measurements were obtained on unaged dumbbell-shaped test 
specimens using a table model Instron& Tester, Model 4301, and the test 
results were calculated in accordance with ASTM D 412. The Instron.RTM. 
Tester (a testing machine of the constant rate-of-jaw separation type) is 
equipped with suitable grips capable of clamping the test specimens 
without slippage. Unaged samples and samples heat aged for 28 days at 
116.degree. C. of Compound Nos. 3-6 were tested. All unaged and heat-aged 
dumbbell-shaped test specimens were allowed to set for about 24 hours, 
before testing was carried out at a crosshead speed of 20 inches per 
minute at 23.degree. C. According to the stress-strain property data shown 
in Table I, the unaged test samples of Compound No. 3 has a 100% modulus 
(psi) of 525, a 300% modulus (psi) of 685, a tensile strength at break 
(psi) of 1000 and an elongation at break (%) of 565. The unaged sample of 
Compound No. 4 has a 100% modulus (psi) of 845, a 300% modulus (psi) of 
990, a tensile strength at break (psi) of 1305 and an elongation at break 
(%) of 512. The unaged sample of Compound No. 5 has a 100% modulus (psi) 
of 885, a 300% modulus (psi) of 1080, a tensile strength at break (psi) of 
1465 and an elongation at break (%) of 520. Unaged sample of Compound No. 
6 has a 100% modulus (psi) of 865, a 300% modulus (psi) of 1025, a tensile 
strength at break (psi) of 1440 and an elongation at break (%) of 550. As 
shown from the stress-strain data in Table II, the unaged dumbbell-shaped 
test samples of Compound Nos. 3-6 have similar stress-strain properties as 
measured at 23.degree. C. 
Heat aged dumbbell-shaped test samples of Compound Nos. 3-6 were also 
tested for their stress-strain properties at 23.degree. C. According to 
the stress-strain property data shown in Table II, the heat aged sample of 
Compound No. 3 has a 100% modulus (psi) of 855, a 300% modulus (psi) of 
1210, a tensile strength at break (psi) of 1318 and an elongation at break 
(%) of 365. The heat aged sample of Compound No. 4 has a 100% modulus 
(psi) of 1180, a 300% modulus (psi) of 1860, a tensile strength at break 
(psi) of 1999 and an elongation at break (%) of 327. The heat aged sample 
of Compound No. 5 has a 100% modulus (psi) of 1130, a 300% modulus (psi) 
of 1605, a tensile strength at break (psi) of 1850 and an elongation at 
break (%) of 301. The heat aged sample of Compound No. 6 has a 100% 
modulus (psi) of 1160, a 300% modulus (psi) of 1750, a tensile strength at 
break (psi) of 1788 and an elongation at break (%) of 301. As shown from 
the stress-strain data in Table II, the heat aged samples of Compound Nos. 
3-6 have similar stress-strain properties as measured at 23.degree. C. 
These roof shingle compositions showed excellent resistance to heat aging, 
based on the properties provided in Table II. 
Die C tear properties for unaged samples and samples heat aged for 28 days 
at 116.degree. C. were determined by using a metal die (90.degree. angle 
die C) to remove the test specimens from cured 45 mil six by six-inch flat 
rubber slabs (compression molded 30 minutes at 160.degree. C.) in 
accordance with ASTM D 624. All die C tear specimens, were allowed to set 
for about 24 hours, before testing was carried out at 23.degree. C., as 
shown in Table II. 
Tear properties, in lbs./inch, were obtained using a table model 
Instron.RTM. Tester, Model 4301 and the test results were calculated in 
accordance with ASTM Method D624. The unaged test samples of Compound Nos. 
3-6 have die C tear values at 23.degree. C. of 267, 334, 325 and 342 
lbs./inch, respectively. The heat aged samples of Compound Nos. 3-6 have a 
die C tear values at 23.degree. C. of 289, 316, 318 and 314 lbs./inch, 
respectively. As shown in Table II, the unaged and heat aged samples of 
Compound Nos. 3-6 have similar die C tear properties. Again, the roof 
shingle compositions featuring the colored rubber dust (20 mesh) had 
excellent heat aging resistance. 
Shore "A" hardness, which measures the hardness of the cured roofing 
shingle composition, was conducted at 23.degree. C. in accordance with 
ASTM Method D 2240 for unaged and heat aged samples of Compound Nos. 3-6. 
The cured test specimens were allowed to set for about 24 hours prior to 
testing. The unaged samples of Compound Nos. 3-6 have Shore "A" hardness 
values at 23.degree. C. of 88, 90, 91 and 90, respectively. 
The heat aged samples of Compound Nos. 3-6 have Shore "A" hardness values 
at 23.degree. C. of 89, 92, 92 and 91, respectively. As shown in Table II, 
the unaged and heat aged samples of Compound Nos. 3-6 have very similar 
Shore "A" hardnesses . 
As can be seen from the data presented in Table II, colored, high 
durometer, EPDM-based polymer roofing compositions, (Compound Nos. 3-6) 
exhibit similar cure, compound viscosity, stress-strain, die C tear, and 
Shore "A" hardness properties as compared to the control (normal colored) 
roofing shingle composition (Compound No. 3). The compositions featuring 
the colored EPDM rubber dust demonstrated excellent retention of heat aged 
properties after aging 28 days at 116.degree. C. Also, changes in cured 
compound durometer were minimal. For example, only 1 to 2 point changes in 
durometer readings were reported when comprising the unaged and heat aged 
test samples shown in Table II. 
As can be seen from the data presented in Table II, Compound Nos. 3-6 
exhibit similar cure characteristics (i.e. scorch time, time to 50% cure 
and time to 90% cure), stress-strain properties, die C tear properties, 
and Shore "A" hardnesses. For these reasons, the EPDM-based roof shingle 
compositions, as shown in Table II (Compound Nos. 3-6), are suitable for 
use as colored, high durometer EPDM-based roofing shingle compositions for 
sloped roofs. 
Compound Nos. 7-10 in Table III provide examples of sulfur curable, 
fiber-reinforced, high durmoeter EPDM-based roofing shingle compositions 
of the present invention, and are submitted for the purpose of further 
illustrating the nature of the present invention. 
TABLE III 
______________________________________ 
Properties of Glass Fiber-Reinforced EPDM-Based 
Roof Shingle Compositions 
COMPOUND NOS. 
7 8 9 10 
______________________________________ 
Royalene EPDM 100 100 100 100 
Magnesium Hydroxide 150 150 150 150 
Mica 50 50 50 50 
Processing Aid 2.5 2.5 2.5 2.5 
Paraffinic Process Oil 50 50 50 50 
Titanium Dioxide 7.5 7.5 7.5 7.5 
Zinc Oxide (cure activator) 4.0 4.0 4.0 4.0 
Stearic Acid 1.25 1.25 1.25 1.25 
HDPE 135 135 135 135 
EPDM Cryogrind (40 mesh) 100 100 100 100 
Fiberglass 144A-14C -- 10 -- -- 
Fiberglass 408A-14C -- -- 10 -- 
Fiberglass 415A-14C -- -- -- 10 
Masterbatch 600.25 600.25 600.25 600.25 
Cure Package 
Sulfur 1.0 1.0 1.0 1.0 
MBTS accelerator 2.15 2.15 2.15 2.15 
ZDBDC accelerator 1.40 1.40 1.40 1.40 
TOTAL 604.80 604.80 604.80 604.80 
Rheometer at 320.degree. F. (160.degree. C.), mini-die, 3.degree. arc 
Scorch time, minutes 
4:53 4:42 4:37 4:39 
Time to 50% cure, minutes 7:18 7:02 6:48 7:07 
Time to 90% cure, minutes 13:50 13:11 12:57 13:38 
Minimum torque, lb.-inch 9.2 10.1 9.9 9.3 
Maximum torque, lb.-inch 21.2 20.8 21.4 21.5 
Mooney Scorch at 275.degree. F. (135.degree. C.) - large rotor 
Minimum Viscosity, Mu 
44.5 45.1 46.0 45.4 
T.sub.5, minutes 18.5 17.6 18.1 18.3 
T.sub.35, minutes 33.7 32.8 33.1 33.7 
Stress-Strain Properties at 73.degree. F. (23.degree. C.) 
Unaged 
100% Modulus, psi 525 745 875 765 
300% Modulus, psi 685 845 920 900 
Tensile at break, psi 1000 1023 1115 1120 
Elongation at break, % 565 497 484 500 
Heat Aged for 28 Days at 240.degree. F. (116.degree. C.) 
100% Modulus, psi 855 1088 1080 1075 
300% Modulus, psi 1210 1360 1430 1195 
Tensile at break, psi 1318 1385 1505 1440 
Elongation at break, % 365 315 340 320 
Die C Tear Properties at 73.degree. F. (23.degree. C.) 
Unaged 
Lbs/inch 267 316 306 311 
Heat Aged for 28 Days at 240.degree. F. (116.degree. C.) 
Lbs/inch 289 313 320 320 
Shore "A" Hardness 
Unaged-Tested at 73.degree. F. (23.degree. C.) 
88 91 89 91 
Heat Aged for 28 Days at 240.degree. F. 89 89 89 89 
(116.degree. C.) 
Bending Modulus (according to ASTM D 747) 
Sample #1 (force in psi .times. 10.sup.5) 
1.31 3.11 2.16 1.55 
Sample #2 (force in psi .times. 10.sup.5) 1.49 2.87 2.49 1.96 
Average Force (force in psi .times. 10.sup.5) 1.40 2.99 2.33 1.76 
______________________________________ 
The examples illustrated in Table III (Compound Nos. 7-10) are sulfur 
curable, glass fiber-reinforced, high durometer, EPDM-based roofing 
shingle compositions prepared from a composition of matter comprising: a 
polymer component, a thermoplastic modifying polymer, reinforcing glass 
fibers, mineral fillers, processing aids, processing oil, cure activators 
and other additives. A sulfur cure package was added to the roofing 
shingle compositions of Table III. Compound Nos. 7-10 comprise Royalene 
EPDM terpolymer as the polymer component of the roofing shingle 
composition. To the 100 parts of EPDM terpolymer of Compound Nos. 7-10, 
150 parts by weight magnesium hydroxide, 50 parts by weight mica, 2.5 
parts by weight paraffinic processing aid, 135 parts by weight high 
density polyethylene, 100 parts by weight EPDM cryogrind (40 mesh) per 100 
parts EPDM terpolymer, 50 parts by weight Sunpar 2280 process oil, 7.5 
parts by weight titanium dioxide, 4.0 parts by weight zinc oxide and 1.25 
parts by weight stearic acid. To Compound No. 8, 10 parts by weight of 
chopped fiberglass 144A-14C per 100 parts of EPDM terpolymer was added to 
create the masterbatch. To Compound No. 9, 10 parts by weight chopped 
fiberglass 408A-14C, per 100 parts of EPDM terpolymer was added to create 
the masterbatch. To Compound No. 10, 10 parts by weight chopped fiberglass 
415A-14C, per 100 parts of EPDM terpolymer was added to create the 
masterbatch. A sulfur cure package comprising 1.0 part by weight sulfur, 
2.15 parts by weight benzothiazyl disulfide (MBTS) accelerator and 1.40 
parts by weight zinc dibutyldithiocarbamate (ZDBDC) was added to each of 
Compound Nos. 7-10. Each of the compounds were prepared utilizing standard 
polymer mixing techniques and equipment by mixing together the ingredients 
listed hereinabove. 
In order to evaluate the properties of the glass fiber-reinforced, high 
durometer, EPDM-based roofing shingle compositions comprising Royalene 
EPDM terpolymer, Compound Nos. 7-10 were prepared by compounding the EPDM 
terpolymers, thermoplastic modifying polymers, reinforcing glass fibers, 
mineral fillers, process oil and other additives in a type B Banbury 
internal mixer and resheeted using a hot two-roll mill as described 
hereinabove. The sulfur/accelerator cure package was added to the 
masterbatch in the Banbury mixer and again resheeted to the proper 
dimensions on a hot two-roll mill. The results of the various physical 
properties tested, including stress-strain properties, die-C tear 
resistance Shore "A" hardness and bending modulus are reported in Table 
mi. 
The cure characteristics of Compound No. 7 (control) without any chopped 
glass fiber and Compound Nos. 8-10 each with 10 parts chopped glass fiber 
per 100 parts EPDM terpolymer were determined by means of a Monsanto 
Oscillating Disc Rheometer (described in detail in American Society of 
Testing and Materials Standard, ASTM D 2084). A mini-die was used to 
measure the scorch time, cure rates and state of cure. During actual 
testing, the metal die oscillated at a 3.degree. arc. According to the 
rheometer data shown in Table III, incorporation of chopped glass fiber 
had virtually no influence on scorch time (time to two point rise), time 
to 50% and 90% cure and the overall state of cure. 
Test method (ASTM D 1646) covers the use of the shearing disc viscometer 
for measuring the Mooney Viscosity of raw polymer and fully compounded 
rubber composition. The viscosity of the fully compounded rubber compound 
during vulcanization can be detected with this instrument as evidenced by 
an increase in Acompound viscosity. Therefore, this test method can be 
used to determine incipient cure time and the rate of cure during very 
early stages of vulcanization. Based on Mooney scorch at 135.degree. C. 
data, addition of the chopped glass fiber in the roofing shingle 
compositions had only minimal effect on compound viscosity and processing 
safety (scorch safety). 
For testing stress-strain properties at 23.degree. C., dumbbell-shaped 
specimens were cut using the appropriate metal die from individual cured 
45 mil six by six-inch flat rubber slabs (compression molded 30 minutes at 
160.degree. C.) in accordance with ASTM D 412 (Method A--dumbbell and 
straight). Modulus (psi) tensile strength at break (psi) and elongation at 
break (%) measurements were obtained on unaged dumbbell-shaped test 
specimens using a table model InstronP Tester, Model 4301, and the test 
results were calculated in accordance with ASTM D 412. The Instron.RTM. 
Tester (a testing machine of the constant rate-of-jaw separation type) is 
equipped with suitable grips capable of clamping the test specimens 
without slippage. Unaged test samples and test samples heat aged for 28 
days at 116.degree. C. of Compound Nos. 7-10 were tested. All 
dumbbell-shaped specimens were allowed to set for about 24 hours, before 
testing was carried out at 23.degree. C. According to the stress-strain 
property data shown in Table III, the unaged test sample of Compound No. 7 
(control) has a 100% modulus (psi) of 525, a 300% modulus (psi) of 685, a 
tensile strength at break (psi) of 1000 and an elongation at break (%) of 
565. The unaged test sample of Compound No. 8 has a 100% modulus (psi) of 
745, a 300% modulus (psi) of 845, a tensile strength at break (psi) of 
1023 and an elongation at break (%) of 497. The unaged test sample of 
Compound No. 9 has a 100% modulus (psi) of 875, a 300% modulus (psi) of 
920, a tensile strength at break (psi) of 1115 and an elongation at break 
(%) of 484. The unaged test sample of Compound No. 10 has a 100% modulus 
(psi) of 765, a 300% modulus (psi) of 900, a tensile strength at break 
(psi) of 1120 and an elongation at break (%) of 500. As shown from the 
results in Table III, the unaged test samples of Compound Nos. 7-10 have 
similar stress-strain properties as measured at 23.degree. C. 
Heat aged samples of Compound Nos. 7-10 were also tested for their 
stress-strain properties at 23.degree. C. According to the stress-strain 
property data shown in Table III, the heat aged sample of Compound No. 7 
(control) has a 100% modulus (psi) of 855, a 300% modulus (psi) of 1210, a 
tensile strength at break (psi) of 1318 and an elongation at break (%) of 
365. The heat aged sample of Compound No. 8 has a 100% modulus (psi) of 
1088, a 300% modulus (psi) of 1360, a tensile strength at break (psi) of 
1385 and an elongation at break (%) of 315. The heat aged sample of 
Compound No. 9 has a 100% modulus (psi) of 1080, a 300% modulus (psi) of 
1430, a tensile strength at break (psi) of 1505 and an elongation at break 
(%) of 340. The heat aged sample of Compound No. 10 has a 100% modulus 
(psi) of 1075, a 300% modulus (psi) of 1195, a tensile strength at break 
(psi) of 1440 and an elongation at break (%) of 320. As shown from the 
data in Table III, the heat aged samples of Compound Nos. 7-10 have 
similar stress-strain properties as measured at 23.degree. C. Modest 
increases in tensile strength were measured after heat aging the test 
samples for 28 days at 116.degree. C. 
Die C tear properties for unaged and samples heat aged for 28 days at 
116.degree. C. were determined by using a metal die (90.degree. angle die 
C) to remove the test specimens from cured 45 mil six by six-inch flat 
rubber slabs (compression molded 30 minutes at 160.degree. C.) in 
accordance with ASTM D 624. All die C tear specimens, were allowed to set 
for about 24 hours, before testing was carried out at 23.degree. C., as 
shown in Table III. 
Tear properties, in lbs./inch, were obtained using a table model InstronO 
Tester, Model 4301 and the test results were calculated in accordance with 
ASTM Method D624. The unaged test samples of Compound Nos. 7-10 have a die 
C tear value at 23.degree. C. of 276, 316, 306 and 311 lbs./inch, 
respectively. The heat aged samples of Compound Nos. 7-10 have die C tear 
values at 23.degree. C. of 289, 313, 320, and 320 lbs./inch, respectively. 
As shown in Table III, the unaged and heat aged samples of Compound Nos. 
7-10 have similar die C tear properties. Again, all test samples 
demonstrated excellent heat aging resistance. 
Shore "A" hardness, which measures the hardness of the cured roofing 
shingle composition, was conducted at 23.degree. C. in accordance with 
ASTM Method D 2240 for unaged and heat aged samples of Compound Nos. 7-10. 
The cured test specimens were allowed to set for about 24 hours prior to 
testing. The unaged samples of Compound Nos. 7-10 have Shore "A" hardness 
values at 23.degree. C. of 88, 91, 89 and 91, respectively. Each of the 
heat aged samples of Compound Nos. 7-10 have Shore "A" hardness readings 
at 23.degree. C. of 89. As shown in Table III, the unaged and heat aged 
samples of Compound Nos. 7-10 have very similar Shore "A" hardnesses 
values. 
The American Society of Testing and Materials Standard test method D 747 
measures the relative bending modulus (stiffnless) of materials. The above 
values represent the force (in psi) required to bend each cured 45 mil 
test sample. Test specimen width can be between 5 and 25.4 mm (0.25 and 
1.0 inch). Minimum specimen thickness was measured to the nearest 0.025 mm 
(0.001 inch). This test is desirable for testing the bending modules of 
semi-rigid materials. All numbers shown in Table III are in 
psi.times.10.sup.5. 
The samples of chopped glass fiber reinforcement listed in Table III are 
all four millimeters in length and have a filament diameter of 14 microns. 
These materials are all commercially available from Owens Corning. 
These materials (Compound Nos. 7-10) showed excellent ozone aging 
resistance. For example, when tested under 50% strain in the bent loop 
configuration and exposed to 100 PPHM ozone for as long as 600 hours at 
40.degree. C. no cracking or crazing was observed on the exposed surface 
of the cured roof shingle compositions. These materials also showed 
excellent low temperature properties. For instance, the brittle point for 
Compound No. 7 was determine to be -56.2.degree. C. (-69.2.degree. F.). 
As can be seen from the data presented in Table III, glass 
fiber-reinforced, high durometer, EPDM-based roofing shingle compositions, 
(Compound Nos. 7-10) exhibit similar stress-strain, die C tear, Shore "A" 
hardness and bending modulus properties. 
Based on the foregoing results in Table III with respect to cure 
characteristics, compound viscosity, stress-strain properties, die C tear 
properties and Shore "A" hardnesses, the high durometer EPDM-based roofing 
shingle compositions listed in Table III are suitable for the manufacture 
of slatelike and colored, fiber-reinforced, high durometer, EPDM-based 
roofing shingles for covering sloped roofs. Incorporation of 10 parts of 
chopped glass fiber did increase the stiffness of the roof shingle 
composition as seen in the bending modulus data shown in Table III. Also, 
the presence of 10 parts chopped glass fiber did not have a negative 
influence on any of the unaged and heat aged physical properties. 
Based on the foregoing disclosure, it should now be apparent that the use 
of the roofing shingle compositions described herein will carry out the 
objects set forth hereinabove. It is, therefore, to be understood that any 
variations evident fall within the scope of the claimed invention and 
thus, the selection of specific component elements can be determined 
without departing from the spirit of the invention herein disclosed and 
described. In particular, it will be understood that the polymer 
compositions exemplified herein according to the present invention are not 
necessarily limited to those having EPDM terpolymers of the preferred 
embodiments. Moreover, at noted, hereinabove, other fillers or mixtures 
thereof and processing oils might be substituted for the specific fillers 
and oils exemplified hereinabove, and other ingredients may be optionally 
employed. Thus, the scope of the invention shall include all modifications 
and variations that may fall within the scope of the attached claims.