U.S. patent application number 14/776791 was filed with the patent office on 2016-02-04 for bonding adhesive and adhered roofing systems prepared using the same.
This patent application is currently assigned to Firestone Building Products Co., LLC. The applicant listed for this patent is FIRESTONE BUILDING PRODUCTS CO., LLC. Invention is credited to Joseph CARR, Jiansheng TANG.
Application Number | 20160032158 14/776791 |
Document ID | / |
Family ID | 50983102 |
Filed Date | 2016-02-04 |
United States Patent
Application |
20160032158 |
Kind Code |
A1 |
TANG; Jiansheng ; et
al. |
February 4, 2016 |
BONDING ADHESIVE AND ADHERED ROOFING SYSTEMS PREPARED USING THE
SAME
Abstract
A bond adhesive composition comprising a polymer having a
silicon-containing hydrolyzable terminal group and a hydrocarbon
resin, where the composition is substantially devoid of phenolic
resin.
Inventors: |
TANG; Jiansheng; (Westfield,
IN) ; CARR; Joseph; (Indianapolis, IN) |
|
Applicant: |
Name |
City |
State |
Country |
Type |
FIRESTONE BUILDING PRODUCTS CO., LLC |
Indianapolis |
IN |
US |
|
|
Assignee: |
Firestone Building Products Co.,
LLC
Indianapolis
IN
|
Family ID: |
50983102 |
Appl. No.: |
14/776791 |
Filed: |
March 17, 2014 |
PCT Filed: |
March 17, 2014 |
PCT NO: |
PCT/US14/30257 |
371 Date: |
September 15, 2015 |
Related U.S. Patent Documents
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Application
Number |
Filing Date |
Patent Number |
|
|
61786794 |
Mar 15, 2013 |
|
|
|
Current U.S.
Class: |
156/329 ;
524/314 |
Current CPC
Class: |
C08G 65/336 20130101;
C09J 201/10 20130101; C09J 109/00 20130101; B32B 2255/26 20130101;
B32B 2307/728 20130101; B32B 7/12 20130101; B32B 37/12 20130101;
C09J 5/00 20130101; B32B 2419/06 20130101; E04D 5/08 20130101; C09J
175/04 20130101; E04D 12/00 20130101; C09J 2499/00 20130101; E04D
2015/042 20130101; E04D 3/36 20130101; C09J 171/00 20130101; E04D
11/00 20130101; C09J 201/02 20130101; B32B 25/16 20130101; B32B
2395/00 20130101; E04D 5/148 20130101; E04D 11/02 20130101; C09D
171/02 20130101; E04D 7/005 20130101; B32B 2319/00 20130101; B32B
11/044 20130101; C09D 171/02 20130101; C08L 57/02 20130101 |
International
Class: |
C09J 171/00 20060101
C09J171/00; E04D 5/14 20060101 E04D005/14; E04D 7/00 20060101
E04D007/00; E04D 3/36 20060101 E04D003/36 |
Claims
1. A bond adhesive composition comprising: i. a polymer having a
silicon-containing hydrolyzable terminal group; and ii. a
hydrocarbon resin, where the composition is substantially devoid of
phenolic resin, wherein the composition further includes a
plasticizer.
2. The composition of claim 1, where the composition further
includes an adhesion promoter.
3. The composition of claim 1, where the composition further
includes a catalyst.
4. The composition of claim 1, where the composition further
includes a moisture scavenger.
5. The composition of claim 1, where the composition further
includes a thixotropic compound.
6. The composition of claim 1, where the polymer having a
silicon-containing hydrolyzable terminal group is a
silane-terminated polymer.
7. (canceled)
8. The composition of claim 1, where the adhesive composition has a
dynamic viscosity of less than 20,000 cPs by using a Brookfield
viscometer equipped with a #6 spindle operating at room temperature
and 10 rpm.
9. The composition of claim 1, where the adhesive composition has a
dynamic viscosity of less than 15,000 cPs by using a Brookfield
viscometer equipped with a #6 spindle operating at room temperature
and 10 rpm.
10. A method for forming an adhered membrane roof system, the
method comprising: i. applying a bond adhesive to a substrate on a
roof to form an adhesive layer, where the bond adhesive includes a
polymer having a silicon-containing hydrolyzable terminal group and
a hydrocarbon resin devoid of phenolic resin; and ii. applying a
membrane directly to the adhesive layer.
11. The method of claim 10, where the adhesive forms a
substantially continuous layer between the substrate and the
membrane over at least 40% of the entire roof surface.
12. The method of claim 10, where the method is devoid of any step
of applying the adhesive directly to the rubber membrane.
13. The method of claim 10, where said step of applying the
adhesive includes dip and roll techniques.
14. The method of claim 10, where said step of applying the
adhesive includes spraying the adhesive on the substrate.
15. The method of claim 10, where the substrate includes an
insulation board.
16. The method of claim 10, where the substrate includes a
coverboard.
17. The method of claim 10, where the substrate includes an
existing membrane.
18. The method of claim 10, where the existing membrane is a
roofing membrane.
19. The method of claim 10, where the existing membrane includes an
asphalt-based roofing membrane.
20. The method of claim 10, where said step of applying a membrane
includes applying an EPDM membrane.
21. The method of claim 10, where the membrane is a rubber-based
membrane.
22. The method of claim 10, where the membrane is a
thermoplastic-based membrane.
23. The method of claim 10, where the bond adhesive further
includes an adhesion promoter.
24. The method of claim 10, where the bond adhesive further
includes a catalyst.
25. The method of claim 10, where the bond adhesive further
includes a moisture scavenger.
26. The method of claim 10, where the bond adhesive further
includes a thixotropic compound.
27. The method of claim 10, where the polymer having a
silicon-containing hydrolyzable terminal group is a
silane-terminated polymer.
Description
[0001] This application claims the benefit of U.S. Provisional
Application Ser. No. 61/786,794, filed Mar. 15, 2013, which is
incorporated herein by reference.
FIELD OF THE INVENTION
[0002] Embodiments in the invention are directed toward a
silicon-containing bonding adhesive and adhered roofing systems
prepared with the adhesive.
BACKGROUND OF THE INVENTION
[0003] Polymeric membranes, such as cured sheets of
ethylene-propylene-diene copolymer rubber (EPDM) or extruded sheet
of thermoplastic olefins (TPO), are often used in the construction
industry to cover flat or low-sloped roofs. These membranes, which
may also be referred to as panels, are typically delivered to a
construction site in a bundled roll, transferred to the roof, and
then unrolled and positioned. The sheets are then affixed to the
building structure by employing varying techniques such as
mechanical fastening, ballasting, and/or adhesively adhering the
membrane to the roof. The roof substrate to which the membrane is
secured may include a variety of materials depending on the
situation. For example, the surface may be a concrete, metal, or
wood deck, it may include insulation or recover board, and/or it
may include an existing membrane.
[0004] In addition to securing the membrane to the roof--which mode
of attachment primary seeks to prevent wind uplift--the individual
membrane panels, together with flashing and other accessories, are
positioned and adjoined to achieve a waterproof barrier on the
roof. Typically, the edges of adjoining panels are overlapped, and
these overlapping portions are adjoined to one another through a
number of methods depending upon the membrane materials and
exterior conditions. One approach involves providing adhesives or
adhesive tapes between the overlapping portions, thereby creating a
water-resistant seal.
[0005] Thus, there are two modes of membrane attachment that are
used in conjunction. The first seeks to anchor the membrane to the
roof, while the second seeks to create a water-impervious barrier
by attaching individual adjacent membrane panels to each other or
to flashing. Inasmuch as these modes of membrane attachment seek
entirely different goals, the mechanisms by which they operate are
likewise distinct.
[0006] Adhesive attachment is typically employed to form adhered
roofing systems. The membrane may be adhered to the roof substrate
substantially across the entire planar surface of the membrane to
form fully-adhered systems. In other words, a majority, if not all,
of the membrane panel is secured to the roof substrate as opposed
to mechanical attachment methods which can only achieve direct
attachment in those locations where a mechanical fastener actually
affixes the membrane. Fully-adhered roofing systems are
advantageously installed where maximum wind uplift prevention is
desired. Also, fully-adhered systems are desirable in re-roofing
situations, especially where the new membrane is placed over an
existing membrane (a technique that is commonly referred to as
re-skinning).
[0007] Several techniques are employed to prepare fully-adhered
roofing systems. One technique includes the use of a fleece-backed
EPDM membrane that is secured to the substrate by using a low-rise
polyurethane foam adhesive that is sprayed over the substrate. Once
the adhesive polyurethane foam is applied, the fleece-backed
membrane is applied to the adhesive layer, which attaches itself to
the fleece backing. Alternatively, nitrile-based bond adhesives can
be applied to the substrate and the fleece-backed EPDM membrane can
be secured thereto. Because these systems require fleece-backed
membranes, they are expensive and suffer from manufacturing
inefficiencies relating to the need to secure the fleece to the
membrane.
[0008] Other techniques employ conventional EPDM membrane sheet,
which is not modified with a fleece backing. In these situations,
it is common to employ a contact bonding method whereby technicians
coat both the membrane and the substrate that receives the membrane
with an adhesive. The adhesive is then typically allowed to at
least partially set to, among other things, build some wet green
strength. The membrane is then mated with the substrate via the
partially-set adhesive. Because the volatile components (e.g.
solvent) of the adhesives are "flashed off" prior to mating, good,
early (green) bond strength can advantageously be developed.
[0009] One technique employs a water-borne bond adhesive that is
applied to the substrate and then the EPDM membrane can be applied
to the adhesive layer. While this attachment technique has proven
useful, the use is generally limited to ambient weather conditions
(e.g. greater than 40.degree. C.) and/or in conjunction with porous
substrates that absorb water thereby allowing the adhesive to dry
or cure without blistering the membrane.
[0010] In other situations, solvent-based adhesives are employed,
such as polychloroprene-based bond adhesives. While the use of
known solvent-based adhesives has proven versatile to the extent
that the substrate need not be porous and cold-weather application
is feasible, the technique requires application of the adhesive to
both the substrate and the membrane, followed by a time delay to
allow the solvent to flash off, and then a mating of the two
adhesive surfaces (i.e., the adhesive coated membrane is mated to
the adhesive coated substrate).
[0011] In yet other situations, 100% solids bond adhesives are
employed. For example, U.S. Pat. No. 7,767,308 teaches a
moisture-curable bond adhesive that includes a polymer or a
combination of polymers having silicon-containing hydrolyzable
terminal groups, a phenolic resin, and a non-polymeric
silicon-containing hydrolyzable compound. While these bond
adhesives are touted for being free of volatile organic compounds
(VOCs), safe for chronic exposure, and non-flammable, and yet
provide a high initial peel strength and/or high peel strength upon
being fully cured between a roof substrate and a rubber membrane,
it would nonetheless be desirable to formulate a bond adhesive that
does not include a phenolic resin.
[0012] While both solvent-based and water-based adhesives may be
used as contact adhesives, solvent-based bonding adhesives offer
advantages. For example, the flash-off period, which is the time
required to allow solvent evaporation prior to mating, can be
between 5 and 40 minutes, and is less susceptible to environmental
conditions, such as temperature, than water-based adhesive systems.
Solvent-based systems, on the other hand, can be problematic. For
example, the solvent employed in the system can cause membrane
swelling and/or blistering. It is believed swelling and blistering
results from solvent compatibility with the membrane and/or a
component of the membrane. Other problems can include blushing,
which is the formation of condensation on the surface of the film
formed upon application of the adhesive to the membrane. Blushing
can have a deleterious impact on the bond strength and/or quality
of the bond formed by the adhesive and is therefore not
desirable.
[0013] The evaporation of solvents can be problematic, especially
as the desire to minimize release of volatile organic compounds
increases. Thus, both water-borne and solvent-borne systems known
in the art today have limitations, and there is therefore a desire
for a bond adhesive that overcomes these advantages.
SUMMARY OF THE INVENTION
[0014] One or more embodiments of the present invention provide a
bond adhesive composition comprising a polymer having a
silicon-containing hydrolyzable terminal group and a hydrocarbon
resin, where the composition is substantially devoid of phenolic
resin.
[0015] Other embodiments of the present invention provide a method
for forming an adhered membrane roof system, the method comprising
applying a bond adhesive to a substrate on a roof to form an
adhesive layer, where the bond adhesive includes a polymer having a
silicon-containing hydrolyzable terminal group and a hydrocarbon
resin devoid of phenolic resin and applying a membrane directly to
the adhesive layer.
BRIEF DESCRIPTION OF THE DRAWINGS
[0016] The FIGURE is a cross sectional view of a roofing system
including EPDM membrane adhered to a substrate using an adhesive
according to one or more embodiments of the present invention.
DETAILED DESCRIPTION OF ILLUSTRATIVE EMBODIMENTS
[0017] Embodiments of the invention are based, at least in part, on
the discovery of a bond adhesive that includes a polymer having
silicon-containing hydrolyzable terminal group and a hydrocarbon
resin. These bond adhesives are advantageously devoid or
substantially devoid of phenolic resins. In one or more
embodiments, these bond adhesive compositions can be used to bond
polymeric substrates (e.g. roofing membranes) to other substrates
(e.g., isocyanate construction boards). And, these membranes need
not be fleece-backed membranes. Indeed, fully-adhered systems that
advantageously meet FM 4470/4474 standards for wind uplift can be
prepared in the absence of a fleece backing. Moreover, it has been
unexpectedly discovered that these adhered systems can be mated to
a variety of substrates including existing membranes, which thereby
provides a unique method for re-roofing or re-skinning an existing
roof. Additionally, the adhesives of this invention can be used to
prepare fully-adhered roofing systems by simply applying the
adhesive to the substrate, and then subsequently mating the
membrane to the adhesive layer formed on the substrate without the
need to directly apply the adhesive to the membrane. Still further,
it has been advantageously discovered that the adhesive composition
of the invention can be prepared to have relatively low dynamic
viscosity, which advantageously allows the adhesive to be spread at
relatively high rates of coverage while maintaining technologically
useful adhesive properties. Moreover, adhesive compositions of
certain embodiments can advantageously be prepared with thixotropic
agents that provide the adhesive with relatively high static
viscosity, which likewise improves coverage rates by limiting the
amount of adhesive absorption in the substrate.
Adhesive Composition
[0018] As discussed above, the adhesive compositions of this
invention include a polymer having silicon-containing a
hydrolyzable terminal group and a hydrocarbon resin. In addition,
the adhesive compositions may include an adhesion promoter, a
filler, a catalyst, an antioxidant, a stabilizer, a moisture
scavenger, a crosslink inhibitor (a.k.a retarder), a plasticizer,
and/or a thixotropic compound. In one or more embodiments, the
adhesive composition is a 100% solids composition (i.e. it is
solvent free), and the composition is devoid or substantially
devoid of a phenolic resin.
Silane-Terminated Polymers
[0019] In one or more embodiments, the polymer having
silicon-containing hydrolyzable terminal group may include a
silane-terminated polymer, which may also be referred to as
silyl-terminated polymer. The term "silicon-containing hydrolyzable
terminal group" as used herein means a group wherein at least one
silicon atom is combined with a hydrolyzable group, such as a
methoxy group, which is subject to hydrolysis and polymerization by
moisture.
[0020] The backbone of the polymer having silicon-containing
hydrolyzable terminal groups may be comprised of polyethers,
polyesters, polyurethanes (SPUR), or other suitable backbones.
[0021] Suitable polymers having silicon-containing hydrolyzable
terminal groups are commercially available and/or can be prepared
in accordance with techniques known in the art. Examples of
suitable commercially available polymers having silicon-containing
hydrolyzable terminal groups are Geniosil.TM. STP-E 35
trimethoxysilylpropyl-carbamate-terminated polyether, and
Geniosil.TM. STP-E 30 silane-terminated polyether with
dimethoxy(methyl)silylmethylcarbamate terminal groups, both of
which are available from Wacker Chemical. Another commercially
available polymer having silicon-containing hydrolyzable terminal
groups that may be employed in the adhesive compositions of this
invention is "SPUR+" silane-terminated polyurethanes, which are
available from Momentive. Another suitable commercially available
material is "MS" silyl-terminated polyether (S227H, S303, S327,
S303H, SAX350), which are available from Kaneka.
[0022] While the use of a hydrocarbon resin within the adhesive
compositions of the present invention provide the composition with
an advantageous dynamic viscosity, it has also been discovered that
further adjustments to viscosity can be advantageously
accomplished, while maintaining adequate adhesion, by employing
certain blends of polymers having silicon-containing hydrolyzable
terminal groups. In particular embodiments, these blends include
polymers having a relatively high molecular weight combined with
polymers having a relatively low molecular weight. In one or more
embodiments, the high molecular weight polymers having a
silicon-containing hydrolyzable terminal group have a number
average molecular weight greater than 12,000 g/mole, in other
embodiments greater than 13,000 g/mole, in other embodiments
greater than 14,000 g/mole, and in other embodiment greater than
14,000 g/mole. In one or more embodiments, the high molecular
weight polymers having a silicon-containing hydrolyzable terminal
group have a number average molecular weight of from about 12,000
to 30,000, in other embodiments from about 13,000 to about 25,000,
and in other embodiments from about 14,000 to about 20,000 g/mole.
In these or other embodiments, the high molecular weight polymers
having a silicon-containing hydrolyzable terminal group are
characterized by a polydispersity of from about 1.5 to about 4.0,
in other embodiments from about 1.8 to about 3.5, and in other
embodiments from about 2.0 to about 3.0.
[0023] In these or other embodiments, low molecular weight polymers
having a silicon-containing hydrolyzable terminal group have a
number average molecular weight of less than 12,000 g/mole, in
other embodiments less than 11,000 g/mole, and in other embodiments
less than 10,000 g/mole. In one or more embodiments, the low
molecular weight polymers having a silicon-containing hydrolyzable
terminal group have a number average molecular weight of from about
5,000 to 12,000, in other embodiments from about 7,000 to about
11,000, and in other embodiments from about 8,000 to about 10,000
g/mole. In these or other embodiments, the low molecular weight
polymers having a silicon-containing hydrolyzable terminal group
are characterized by a polydispersity of from about 1.1 to about
3.0, in other embodiments from about 1.2 to about 2.5, and in other
embodiments from about 1.3 to about 2.0.
Hydrocarbon Resin
[0024] As mentioned above, the adhesive composition may include one
or more hydrocarbon resins. In one or more embodiments, the
hydrocarbon resins may include natural resins, synthetic resins,
and low molecular weight polymers or oligomers. The monomer that
may be polymerized to synthesize the synthetic resins or low
molecular weight polymers or oligomers may include those obtained
from refinery streams containing mixtures or various unsaturated
materials or from pure monomer feeds. The monomer may include
aliphatic monomer, cycloaliphatic monomer, aromatic monomer, or
mixtures thereof. Aliphatic monomer can include C.sub.4, C.sub.5,
and C.sub.6 paraffins, olefins, and conjugated diolefins. Examples
of aliphatic monomer or cycloaliphatic monomer include butadiene,
isobutylene, 1,3-pentadiene (piperylene) along with 1,4-pentadiene,
cyclopentane, 1-pentene, 2-pentene, 2-methyl-1-pentene,
2-methyl-2-butene, 2-methyl-2-pentene, isoprene, cyclohexane,
1-3-hexadiene, 1-4-hexadiene, cyclopentadiene, and
dicyclopentadiene. Aromatic monomer can include C.sub.8, C.sub.9,
and C.sub.10 aromatic monomer. Examples of aromatic monomer include
styrene, indene, derivatives of styrene, derivatives of indene, and
combinations thereof.
[0025] In one or more embodiments, examples of hydrocarbon resins
include aliphatic hydrocarbon resins, at least partially
hydrogenated aliphatic hydrocarbon resins, aliphatic/aromatic
hydrocarbon resins, at least partially hydrogenated aliphatic
aromatic hydrocarbon resins, cycloaliphatic hydrocarbon resins, at
least partially hydrogenated cycloaliphatic resins,
cycloaliphatic/aromatic hydrocarbon resins, at least partially
hydrogenated cycloaliphatic/aromatic hydrocarbon resins, at least
partially hydrogenated aromatic hydrocarbon resins, polyterpene
resins, terpene-phenol resins, rosin esters, and mixtures of two or
more thereof.
[0026] In certain embodiments, the synthetic aliphatic or aromatic
hydrocarbon resins may be characterized by a number average
molecular weight (M.sub.n) of from about 300 g/mole to about 3,000
g/mole, and in other embodiments from about 500 g/mole to about
2,000 g/mole. These hydrocarbon resins may also be characterized by
a weight average molecular weight (M.sub.w) of from about 500
g/mole to about 6,000 g/mole, and in other embodiments from about
700 g/mole to about 5,000 g/mole. Molecular weight may be
determined by size exclusion chromatography (SEC) by using a Waters
150 gel permeation chromatograph equipped with the differential
refractive index detector and calibrated using polystyrene
standards.
[0027] In certain embodiments, the hydrocarbon resins include those
produced by thermal polymerization of dicyclopentadiene (DCPD) or
substituted DCPD, which may further include aliphatic or aromatic
monomers. In one embodiment, the DCPD or substituted DCPD is
copolymerized with aromatic monomer, and the final product includes
less than 10% aromatic content. In another embodiment, the
hydrocarbon resin derives from the copolymerization of both
aliphatic monomer and aromatic monomer. In particular embodiments,
the dicyclopentadiene tackifier resin is hydrogenated. Hydrogenated
dicyclopentadiene tackifier resins are commercially available from
Neville.
[0028] In one or more embodiments, synthetic oligomers may include
dimers, trimers, tetramers, pentamers, hexamers, septamers, and
octamers of petroleum distillate monomer. In one or more
embodiments, this petroleum distillate monomer may have a boiling
point of from about 30.degree. to about 210.degree. C. The
oligomers may include byproducts of resin polymerization including
thermal and catalytic polymerization. For example, oligomers may
derive from processes where DCPD, aliphatic monomer, and/or
aromatic monomer are oligomerized.
[0029] The hydrocarbon resins may be characterized by an aromatic
content of from about 1 to about 60, in other embodiments from
about 2 to about 40, and in other embodiments from about 5 to about
10. In one or more embodiments, the tackifier resins are
hydrogenated or partially hydrogenated; useful resins include those
that are at least 50 percent, in other embodiments at least 80
percent, in other embodiments at least 95 percent, and in other
embodiments at least 99 percent or fully hydrogenated. For example,
the hydrocarbon resin prior to grafting may contain less than 90,
in other embodiments less than 50, in other embodiments less than
25, in other embodiments less than 10, in other embodiments less
than 2, in other embodiments less than 1, in other embodiments less
than 0.5, and in other embodiments less than 0.05 olefinic protons.
Aromatic content and olefin content may be measured by .sup.1H-NMR
as measured directly from the .sup.1H NMR spectrum from a
spectrometer with a field strength greater than 300 MHz, and in
other embodiments 400 MHz (frequency equivalent). Aromatic content
includes the integration of aromatic protons versus the total
number of protons. Olefin proton or olefinic proton content
includes the integration of olefinic protons versus the total
number of protons.
[0030] In one or more embodiments, the hydrocarbon resin may be
characterized by a softening point of from about 5.degree. C. to
about 210.degree. C., in other embodiments from about 65.degree. C.
to about 170.degree. C., and in other embodiments from about
90.degree. C. to about 140.degree. C. Softening point can be
determined according to ASTM E-28 (Revision 1996.
[0031] In these or other embodiments, the hydrocarbon resin may be
characterized by a glass transition temperature of less than
120.degree. C., in other embodiments less than 110.degree. C., and
in other embodiment from about -40.degree. C. to about 80.degree.
C. Glass transition temperature may be determined according to ASTM
D 341-88 by using differential scanning calorimetry.
[0032] In these or other embodiments, the hydrocarbon resin may be
characterized by a Saponification number (mg KOH/g resin material)
of greater than 10, in other embodiments greater than 15, and in
other embodiments greater than 19.
[0033] In these or other embodiments, the hydrocarbon resin may be
characterized by an acid number greater than 10, in other
embodiments greater than 15, and in other embodiments greater than
20, and in other embodiments greater than 25.
Adhesion Promoter
[0034] In one or more embodiments, the adhesion promoter includes a
non-polymeric silicon-containing hydrocarbon compound that has a
lower molecular weight than the polymer having a silicon-containing
hydrolysable group (i.e. the silane-terminate polymer). Also, the
adhesion promoter includes at least one hydrolyzable group capable
of reacting with a hydrolyzed functional group on the polymer
having silicon-containing hydrolyzable terminal groups, and
includes at least one moiety capable of interacting (i.e.,
promoting adhesion) with materials that are to be bonded with one
another (such as a rubber membrane material). The expression
non-polymeric, as used to modify the silicon-containing hydrocarbon
compound is meant to exclude polymers and copolymers having at
least 10 repeat units or monomeric units, such as urethane
prepolymers having silicon-containing hydrolyzable terminal groups,
but is meant to encompass oligomeric silicon-containing
hydrolyzable compounds having fewer than 10 repeat units or
monomers, and which are useful for promoting adhesion between a
substrate and a cured adhesive composition. Examples of suitable
aminosilane adhesion promoters that may function as the
non-polymeric silicon-containing hydrolyzable compound include, but
are not limited to gamma-aminopropyltrimethoxysilane,
gamma-aminopropyltriethoxysilane,
gamma-(aminoethyl)-aminopropyltrimethoxy-silane,
methylaminopropyldimethoxysilane,
methyl-gamma-(aminoethyl)-aminopropyldimethoxysilane,
gamma-dimethylaminopropyltrimethoxysilane, and the like.
Plasticizers
[0035] In one or more embodiments, examples of a plasticizer
include phthalic acid esters (such as dioctyl phthalate, diisooctyl
phthalate, dibutyl phthalate, diundecyl phthalate, diisononyl
phthalate, diisodecyl phthalate, diisodocecyl phthalate and
butylbenzyl phthalate); aliphatic dibasic acid esters (such as
dioctyl adipate, isodecyl succinate, and dibutyl sebacate); glycol
esters (such as diethylene glycol dibenzoate and pentaerythritol
ester); aliphatic esters (such as butyl oleate and methyl
acetylricinoleate); phosphoric acid esters (such as tricresyl
phosphate, trioctyl phosphate, and octyldiphenyl phosphate); epoxy
plasticizers (such as epoxidated soybean oil, epoxidated linseed
oil, and benzyl epoxystearate); polyester plasticizers (such as
polyesters of dibasic acid and a divalent alcohol); polyethers
(such as polypropylene glycol and its derivatives); polystyrenes
(such as poly-.alpha.-methylstyrene and polystyrene); polybutadiene
butadiene-acrylonitrile copolymer; polychloroprene; polyisoprene;
polybutene; chlorinated paraffins; benzoic esters; glycol esters;
phosphoric esters; sulfonic esters; and mixtures thereof, wherein
any given compound is different than an ingredient otherwise
included in the composition of the invention.
[0036] In addition, high-molecular weight plasticizers can also be
used. Specific examples of such high-molecular weight plasticizer
include, but are not limited to, vinyl polymers obtainable by
polymerizing a vinyl monomer by various methods; polyalkylene
glycol esters such as diethylene glycol dibenzoate, triethylene
glycol dibenzoate and pentaerythritol esters; polyester
plasticizers obtainable from a dibasic acid, such as sebacic acid,
adipic acid, azelaic acid or phthalic acid, and a dihydric alcohol,
such as ethylene glycol, diethylene glycol, triethylene glycol,
propylene glycol or dipropylene glycol; polyethers such as
polyether polyols, e.g. polyethylene glycol, polypropylene glycol
and polytetramethylene glycol that have a molecular weight of 500
or more, and even further 1,000 or more, and derivatives of these
as obtainable by converting the hydroxyl groups of these polyether
polyols to an ester, ether or the like groups; polystyrenes such as
polystyrene and poly-.alpha.-methylstyrene; polybutadiene,
polybutene, polyisobutylene, butadiene-acrylonitrile,
polychloroprene and the like. In one or more specific embodiments,
plasticizers include propylene glycol dibenzoate, diisononyl
phthalate, and soy methyl esters, Mesamol II, HB-40,
butylbenzylphthalate. In other specific embodiments, the
plasticizers employed are phthalic acid esters. In one or more
embodiments, the plasticizers may include high boiling solvents
that promote tackification, lowering of viscosity, and
sprayability.
Moisture Scavenger
[0037] In one or more embodiments, a moisture scavenger is employed
in the adhesive compositions of this invention. Moisture scavengers
that may be employed include chemical moisture scavengers and
physical moisture scavengers that absorb and/or adsorb moisture. In
particular embodiments, the chemical moisture scavenger is
vinyl-trimethoxysilane, which may be employed in an amount of up to
about 3% by weight based on the total weight of the adhesive
composition. An example of a physical moisture scavenger that may
be employed is 3 A Sieves from UOP, which is a zeolite having 3
Angstrom pores capable of trapping moisture. Other moisture
scavengers that may be employed include oxazoladines and calcium
oxide.
Thixotrope
[0038] In one or more embodiments, suitable thixotropic agents may
include, but are not limited to, polyvinylpyrrolidone, titanate
coupling agents, metal soaps (such as calcium stearate, aluminum
stearate, and barium stearate, aluminum distearate, and aluminum
tristearate), copolymers with acidic groups, compounds having ionic
groups, fumed silica, colloidal silica, asbestine, organic
derivatives of castor oil (such as hydrogenated castor oil
derivatives), treated clays, organic bentonite, modified polyester
polyols (such as polyoxyethylene-polyoxypropylene block
copolymers), aliphatic amides, and polyamides (such as polyamide
waxes). Specific examples include polyamide waxes, such as
"Crayvallac SLX" available from Arkema, or polymerized castor oils
such as Flowtone R from Crayvalley.
Antioxidants
[0039] Antioxidants that may be employed if desired. Examples of
useful antioxidants include hindered phenols and phosphate
esters.
Fillers
[0040] Generally, any compatible filler, such as calcium carbonate
may be employed if desired for a particular application. As the
skilled person will appreciate, fillers will generally be omitted
when the adhesive composition is intended to be sprayed onto one
surface that is subsequently applied to a second surface on which
the adhesive is or is not deposited.
Catalyst
[0041] As mentioned above, the adhesive composition may include one
or more catalysts for the purpose of promoting the crosslinking the
silane-terminated polymer. Without wishing to be bound by any
particular theory, it is believed that these catalysts promote the
hydrolysis and condensation of organosilicon compounds (i.e.,
reactions between the terminal groups of the polymer having
silicon-containing hydrolyzable terminal groups, and reactions
between the optional adhesion promoter when present and the polymer
having silicon-containing hydrolyzable terminal groups). In one or
more embodiments, hydrolysis of organosilicon compounds may be
catalyzed by either acids or bases. Useful basic catalysts that may
be employed in the compositions of this invention include alkali
metal hydroxides such as potassium hydroxide, silanolates such as
lithium silanolate, organic amines, and Lewis bases such as alkali
metal carbonates and bicarbonates. Suitable acid catalysts include
mineral acids such as sulfuric and phosphoric acids, organic acids
such as acetic, propanoic and methane sulfonic acids. Other
suitable acid catalysts include Lewis acids such as aluminum
chloride, organotin compounds such as dibutyl tin dilaurate and
titanium compounds such as the alkyl ortho esters, including
tetrabutyl titanate.
Phenolic Resin
[0042] As mentioned above, the adhesive composition is devoid or
substantially devoid of a phenolic resin. As used herein, the term
phenolic resin refers to a phenol-formaldehyde resin. For example,
the term phenolic resin may include a novolac resin, which is a
phenol-formaldehyde resin where the molar ratio of the formaldehyde
to phenol is less than one. These resins are typically synthesized
by using an acid catalyst. The term phenolic resin also refers
resol resins wherein the molar ratio of the formaldehyde to phenol
is greater than one. These resins are typically synthesized by
using a base catalyst.
Solvent
[0043] As mentioned above, the adhesive composition is devoid or
substantially devoid of a solvent. As used herein, the term solvent
refers to a volatile liquid that is either a VOC or VOC exemption
liquid. Examples of solvents that are excluded include toluene and
acetone.
Amounts
[0044] Silane-Terminated Polymer
[0045] In one or more embodiments, the adhesive compositions of the
invention include at least 25 wt %, in other embodiments at least
30%, and in other embodiments at least 35 wt. % silane-terminated
polymer. In these or other embodiments, the adhesive compositions
of the invention include at most 80%, in other embodiments at most
75%, and in other embodiments at most 70% wt. % silane-terminated
polymer. In one or more embodiments, the adhesive compositions of
the invention include from about 25% to about 80%, in other
embodiments from about 30% to about 75%, and in other embodiments
from about 35% to about 70% wt. % silane-terminate polymer.
[0046] In one or more embodiments, the silane-terminated polymer
component of the adhesive compositions of the present invention
may, in one or more embodiments, include a blend of high and low
molecular weight polymer. In one or more embodiments, the
silane-terminated polymer component includes at least 40 wt %, in
other embodiments at least 50 wt %, and in other embodiments at
least 60 wt % high-molecular weight silane-terminated polymer
(e.g., a molecular weight of greater than 12,000 g/mole), based
upon the entire weight of the silane-terminated polymer component.
In these or other embodiments, the silane-terminated polymer
component includes at most 100 wt %, in other embodiments at most
80 wt %, and in other embodiments at most 70 wt % high-molecular
weight silane-terminated polymer, based upon the entire weight of
the silane-terminated polymer component. In one or more
embodiments, the silane-terminated polymer component of the
adhesive compositions includes from about 40 to about 100, in other
embodiments from about 50 to about 80, and in other embodiments
from about 60 to about 70 weight percent high-molecular weight
silane-terminated polymer, based upon the entire weight of the
silane-terminated polymer component.
[0047] In one or more embodiments, the silane-terminated polymer
component includes at least 0 wt %, in other embodiments at least
20 wt %, and in other embodiments at least 30 wt % low-molecular
weight silane-terminated polymer (a molecular weight of less than
12,000 g/mole), based upon the entire weight of the
silane-terminated polymer component. In these or other embodiments,
the silane-terminated polymer component includes at most 60 wt %,
in other embodiments at most 50 wt %, and in other embodiments at
most 40 wt % low-molecular weight silane-terminated polymer, based
upon the entire weight of the silane-terminated polymer component.
In one or more embodiments, the silane-terminated polymer component
of the adhesive compositions includes from about 0 to about 60, in
other embodiments from about 20 to about 50, and in other
embodiments from about 30 to about 40 weight percent low-molecular
weight silane-terminated polymer, based upon the entire weight of
the silane-terminated polymer component.
[0048] Hydrocarbon Resin
[0049] In one or more embodiments, the adhesive compositions of the
invention include at least 1%, in other embodiments at least 3%,
and in other embodiments at least 5% wt. % hydrocarbon. In these or
other embodiments, the adhesive compositions of the invention
include at most 30%, in other embodiments at most 25%, and in other
embodiments at most 20% wt. % hydrocarbon. In one or more
embodiments, the adhesive compositions of the invention include
from about 1% to about 30%, in other embodiments from about 3% to
about 25%, and in other embodiments from about 5% to about 20% wt.
% hydrocarbon.
[0050] Adhesion Promoters
[0051] In one or more embodiments, the adhesive compositions of the
invention include at least 1%, in other embodiments at least 1.5%,
and in other embodiments at least 2% wt. % adhesion promoter. In
these or other embodiments, the adhesive compositions of the
invention include at most 10%, in other embodiments at most 9%, and
in other embodiments at most 8% wt. % adhesion promoter. In one or
more embodiments, the adhesive compositions of the invention
include from about 1% to about 10%, in other embodiments from about
1.5% to about 9%, and in other embodiments from about 2% to about
8% wt. % adhesion promoter.
[0052] Catalyst
[0053] In one or more embodiments, the adhesive compositions of the
invention include at least 0.05%, in other embodiments at least
0.1%, and in other embodiments at least 0.15 wt. % catalyst. In
these or other embodiments, the adhesive compositions of the
invention include at most 3%, in other embodiments at most 2.5%,
and in other embodiments at most 2% wt. % catalyst. In one or more
embodiments, the adhesive compositions of the invention include
from about 0.05% to about 3%, in other embodiments from about 0.1%
to about 2.5%, and in other embodiments from about 0.15% to about
2% wt. % catalyst.
[0054] Thixatrope
[0055] In one or more embodiments, the adhesive compositions of the
invention include at least 0%, in other embodiments at least 0%,
and in other embodiments at least 0% wt. % thisatrope. In these or
other embodiments, the adhesive compositions of the invention
include at most 6%, in other embodiments at most 5%, and in other
embodiments at most 4% wt. % thixatrope. In one or more
embodiments, the adhesive compositions of the invention include
from about 0% to about 6%, in other embodiments from about 0% to
about 5%, and in other embodiments from about 0% to about 4% wt. %
thixatrope.
[0056] Moisture Scavenger
[0057] In one or more embodiments, the adhesive compositions of the
invention include at least 0.25%, in other embodiments at least
0.5%, and in other embodiments at least 0.75% wt. % moisture
scavenger. In these or other embodiments, the adhesive compositions
of the invention include at most 5%, in other embodiments at most
4%, and in other embodiments at most 3% wt. % moisture scavenger.
In one or more embodiments, the adhesive compositions of the
invention include from about 0.25% to about 5%, in other
embodiments from about 0.5% to about 4%, and in other embodiments
from about 0.75% to about 3% wt. % moisture scavenger.
[0058] Fillers
[0059] In one or more embodiments, the adhesive compositions of the
invention include at least 0%, in other embodiments at least 0%,
and in other embodiments at least 0% wt. % filler. In these or
other embodiments, the adhesive compositions of the invention
include at most 65%, in other embodiments at most 60%, and in other
embodiments at most 55% wt. % filler. In one or more embodiments,
the adhesive compositions of the invention include from about 0% to
about 65%, in other embodiments from about 0% to about 60%, and in
other embodiments from about 0% to about 55% wt. % filler.
[0060] Antioxidants
[0061] In one or more embodiments, the adhesive compositions of the
invention include at least 0.1%, in other embodiments at least
0.15%, and in other embodiments at least 0.2% wt. % antioxidant. In
these or other embodiments, the adhesive compositions of the
invention include at most 3%, in other embodiments at most 2.5%,
and in other embodiments at most 2% wt. % antioxidant. In one or
more embodiments, the adhesive compositions of the invention
include from about 0.1% to about 3%, in other embodiments from
about 0.15% to about 2.5%, and in other embodiments from about
0.15% to about 2% wt. % antioxidant.
[0062] Plasticizer
[0063] In one or more embodiments, the adhesive compositions of the
invention include at least 5%, in other embodiments at least 10%,
and in other embodiments at least 15% wt. % plasticizer. In these
or other embodiments, the adhesive compositions of the invention
include at most 65%, in other embodiments at most 60%, and in other
embodiments at most 55% wt. % plasticizer. In one or more
embodiments, the adhesive compositions of the invention include
from about 5% to about 65%, in other embodiments from about 10% to
about 60%, and in other embodiments from about 15% to about 55% wt.
% plasticizer.
[0064] Solvent
[0065] As discussed above, the adhesive compositions of the
invention may advantageously be 100% solids compositions. In one or
more embodiments, the compositions may be devoid of solvent. In
these or other embodiments, the adhesive compositions are
substantially devoid of solvents, which refers to that amount of
solvent or less that will not have an appreciable impact on the
composition. In one or more embodiments, the compositions of this
invention include less than 10%, in other embodiments less than 8%,
and in other embodiments less than 5% wt. % solvent.
[0066] Phenolic Resin
[0067] As discussed above, the adhesive compositions of the
invention are devoid or substantially devoid of phenolic resin. In
one or more embodiments, the compositions may be devoid of phenolic
resin. In these or other embodiments, the adhesive compositions are
substantially devoid of phenolic resin, which refers to that amount
of solvent or less that will not have an appreciable impact on the
composition. In one or more embodiments, the compositions of this
invention include less than 3%, in other embodiments less than 2%,
and in other embodiments less than 1% wt. % phenolic resin.
Preparation of Adhesive
[0068] The adhesive compositions of the present invention may be
prepared by batch mixing using conventional batch mixing equipment.
In one or more embodiments, the mixer may be equipped with an
emulsifier. The mixing can take place under atmospheric pressure
and at room temperature. The ingredients can conveniently be
introduced to the mixer by first introducing the silane-terminate
polymer followed by introduction of the other ingredients. Mixing
may continue until desired viscosity or level of
dispersion/solubility is achieved. In particular embodiments,
mixing is conducted for at least 100 minutes, in other embodiments
at least 150 minutes, in other embodiments at least 180 minutes,
and in other embodiments at least 190 minutes.
[0069] The adhesive compositions of this invention may be
formulated as either one-part or two-part compositions. In the case
of one-part compositions, the composition is preferably free of
water, and contains a moisture scavenger as discussed above. In the
case of a two part composition that is combined at the point of
use, one part may contain a small amount of water to initiate
moisture curing and components that are not sensitive to moisture,
whereas the other part may contain components that are sensitive to
moisture such as adhesion promoters and more reactive polymers
having silicon-containing hydrolyzable terminal groups.
Characteristics of Adhesive Composition
[0070] In one more embodiments, the adhesive composition is
formulated to offer various characteristics that are advantageous
in practicing the present invention.
[0071] In one or more embodiments, the adhesive composition is
characterized by an advantageous dynamic viscosity. While the
skilled person will appreciate that the static viscosity of the
adhesive can be increased through the use of thixotropic agents,
the dynamic viscosity is generally equivalent to the baseline
viscosity of the adhesive composition. In other words, the
thixotropic agents do not serve to drop the dynamic viscosity below
that of the baseline viscosity. In one or more embodiments, the
dynamic viscosity of the adhesive compositions of this invention,
as measured by using a Brookfield viscometer equipped with a #6
spindle operating at room temperature and 10 rpm, is less than
20,000 cPs, in other embodiments less than 18,000 cPs, in other
embodiments less than 17,000 cPs, in other embodiments less than
16,000 cPs, in other embodiments less than 15,000 cPs, in other
embodiments less than 14,000 cPs, in other embodiments less than
13,000 cPs, and in other embodiments less than 11000 cPs. In one or
more embodiments, the dynamic viscosity of the adhesive
compositions of this invention is from about 3,000 to 20,000 cPs,
in other embodiments from about 3,300 to 18,000 cPs, in other
embodiments from about 4,000 to 16,000 cPs, in other embodiments
from about 4,500 to 15,000 cPs, and in other embodiments from about
4,500 to about 11,000 cPs.
[0072] In one or more embodiments, the adhesive compositions of the
present invention are characterized by an advantageous static
viscosity, which may be measured by a Brookfield viscometer
equipped with a #6 spindle operating at room temperature and 2 rpm.
In one or more embodiments, the static viscosity of the adhesive
composition is at least 24,000 cPs, in other embodiments at least
22,000 cPs, and in other embodiments, at least 20,000 cPs. In one
or more embodiments, the static viscosity of the adhesive
composition is from about 3600 to about 24,000 cPs, in other
embodiments from about 4000 to about 22,000 cPs, and in other
embodiments, from about 4600 to about 20,000 cPs.
[0073] Applicants have advantageously discovered that the
relatively high static viscosity of the adhesive compositions of
this invention give rise to several advantages including higher
coverage rates while maintaining useful adhesion. These higher
coverage rates stem from the low absorption of the adhesive
composition into the substrate. In one or more embodiments, where
the substrate includes a polyisocyanurate insulation board having a
glass-reinforced paper facer, the absorption of the adhesive
material into the facer and/or foam insulation board is, on a
weight basis, less than 60%, in other embodiments less than 55%, in
other embodiments less than 50%, and in other embodiments less than
45%.
[0074] In one or more embodiments, the adhesive compositions of
this invention when used to bond EPDM rubber sheet material to a
high density particleboard have generally exhibited a peel strength
of at least 2.5-4 pounds per linear inch (pli) after 30 day ambient
cure. However, the thermosetting reactions in these compositions
substantially improve with time and temperature. In one or more
embodiments, after 30 days curing at 150 degrees Fahrenheit (normal
rooftop conditions) peel strengths as high as 7.8 pli were
obtained.
INDUSTRIAL APPLICABILITY
[0075] In particular embodiments, the adhesive may be employed in
preparing a fully-adhered roofing membrane system. Practice of the
present invention is not necessarily limited by the selection of a
particular roofing membrane that is secured to a substrate on a
roof surface. As is known in the art, numerous roofing membranes
have been proposed in the art and several are used commercially
including thermoset and thermoplastic roofing membranes.
Commercially available thermoplastic roofing membranes may include
polyvinyl chloride, or polyolefin copolymers. For example,
thermoplastic olefin (TPO) membranes are available under the trade
names UltraPly.TM., and ReflexEON.TM. (Firestone Building
Products). Commercially available thermoset roofing membranes may
include elastomeric copolymers such as ethylene-propylene-diene
copolymer (EPDM) rubber and functionalized olefins such as
chlorosulfonated polyethylene (CSPE). For example, EPDM membranes
are available under the trade name RubberGard.TM., RubberGard
Platinum.TM., RubberGard EcoWhite.TM., and RubberGard MAX.TM.
(Firestone Building Products). Useful EPDM membrane is disclosed
in, for example, U.S. Pat. Nos. 7,175,732, 6,502,360, 6,120,869,
5,849,133, 5,389,715, 4,810,565, 4,778,852, 4,732,925, and
4,657,958, which are incorporated herein by reference. EPDM
membranes are commercially available from a number of sources;
examples include those available under the tradenames RubberGard
(Firestone Building Products) and SURE-SEAL (Carlisle SynTec).
[0076] In particular embodiments, EPDM membranes are employed. As
is known in the art, EPDM membrane panels include vulcanized or
cured rubber compositions. These compositions may include, in
addition to the rubber that is ultimately vulcanized, fillers,
processing oils, and other desired ingredients such as
plasticizers, antidegradants, adhesive-enhancing promoters, etc.,
as well as vulcanizing agents such as sulfur or sulfur-donating
compounds.
[0077] In one or more embodiments, the EPDM roofing panels have a
thickness in accordance with ASTM D-4637-04. In one or more
embodiments, the EPDM roofing panels have a thickness of at least
45 mil.+-.10%, in other embodiments at least 60 mil.+-.10%, and in
other embodiments at least 90 mil.+-.10%. In these or other
embodiments, the EPDM roofing panels may have a thickness of less
than 65 mil.+-.10%, in other embodiments less than 80 mil.+-.10%,
and in other embodiments less than 110 mil.+-.10%.
[0078] In other embodiments, the bond adhesive composition of the
present invention is applied exclusively to the substrate (e.g. the
roof or materials on the roof such as insulation board), and the
membrane is subsequently positioned over the adhesive layer without
application of the adhesive directly to the membrane.
Application Method
[0079] In one or more embodiments of this invention, an adhered
roofing system is constructed by applying the adhesive composition
to a roof substrate to form a layer of adhesive and then
subsequently contacting a surface of an EPDM panel to the layer of
adhesive disposed on the substrate. Advantageously, the process can
be used to construct a roofing system meeting the standards of UL
and Factory Mutual for wind uplift without the need for applying an
adhesive directly to the EPDM panel being installed. Moreover,
these standards can be met in the absence of a fleece or other
backing material applied to the membrane.
[0080] The substrate to which the adhesive composition is applied
may include a roof deck, which may include steel, concrete, and/or
wood. In other embodiments, the adhesive composition may be applied
to insulation materials, such as insulation boards and cover
boards. As those skilled in the art appreciate, insulation boards
and cover boards may carry a variety of facer materials including,
but not limited to, paper facers, fiberglass-reinforced paper
facers, fiberglass facers, coated fiberglass facers, metal facers
such as aluminum facers, and solid facers such as wood, OSB and
plywood, as well as gypsum. In yet other embodiments, the adhesive
composition may be applied to existing membranes. These existing
membranes may include cured rubber systems such as EPDM membranes
or chlorosulfonated polyethylene, thermoplastic polymers systems
such as TPO membranes or PVC membranes, or asphalt-based systems
such as modified asphalt membranes and/or built roof systems.
Advantageously, practice of the present invention provides adhesion
to asphalt-based substrates by offering sufficient oil resistance,
which is required to maintain sufficient adhesion to asphalt
systems.
[0081] In one or more embodiments, the adhesive composition is
applied to the substrate by dip and roll techniques, which are
conventional in the art of applying adhesives to substrates and/or
membrane panels. In other embodiments, the adhesive composition is
applied to the substrate by spraying. In one or more embodiments,
the spraying may be accomplished by using airless spray equipment
or air-assisted spray equipment. In one or more embodiments, the
adhesive composition is atomized during the spraying operation.
Useful spraying equipment is known in the art, such as the spray
equipment available from Graco and Garlock. In other embodiments,
the adhesive can be applied by a power roller, where the adhesive
is pumped to the roller head. Examples include power rollers as
supplied by Garlock. In yet other embodiments, the adhesive can be
applied by using a drop spreader, which generally includes gravity
feeding of the adhesive from a mobile platform such as that sold
under the tradename BetterSpreader (Roofmaster).
[0082] In one or more embodiments, time is permitted between the
application of the adhesive composition and application of the EPDM
panel. In one or more embodiments, this time provided is less than
1 hour, in other embodiments less than 30 minutes, in other
embodiments less than 10 minutes, and in other embodiments less
than 3 minutes. In one or more embodiments, the time provided is
from 1 minute to 1 hour.
[0083] In one or more embodiments, the wet film applied to the
membrane and/or the substrate can be at least 5 mils, in other
embodiments at least 7 mils, in other embodiments at least 10 mils,
in other embodiments at least 13 mils, and in other embodiments at
least 15 mils thick (wet film thickness). In these or other
embodiments, the wet film thickness on each of the respective
layers may be less than 30 mils, in other embodiments less than 25
mils, in other embodiments less than 18 mils, and in other
embodiments less than 15 mils thick (wet film thickness).
[0084] It has advantageously been discovered that practice of the
present invention allows for application of a thinner wet film than
has been previously employed using conventional bond adhesives
while achieving technologically useful bond adhesion. As a result,
during use of the bond adhesive, the application rate can be
reduced (i.e., less bond adhesive is needed per square foot, which
translates into an increased application rate). For example, in one
or more embodiments, technologically useful adhesion can be
achieved at application rates of at least 50 square foot per
gallon, in other embodiments at least 70 square foot per gallon, in
other embodiments at least 100 square foot per gallon, in other
embodiments at least 150 square foot per gallon, in other
embodiments at least 200 square foot per gallon, and in other
embodiments at least 250 square foot per gallon.
[0085] In one or more embodiments, the EPDM panel may be applied to
the adhesive layer using several known techniques. For example, the
EPDM panel may be unrolled on to the adhesive layer.
Roof Construction
[0086] Aspects of the invention may be understood with reference to
the FIGURE, which shows membrane 10 adhered to substrate 12. The
substrate may include one or more of a roof deck 14, an insulation
layer 16, a coverboard 18, and an existing membrane 20. In other
words, membrane 10 may be adhered to roof deck 14, insulation layer
16, coverboard 18, or existing membrane 20. Disposed between an
adhering membrane 10 to substrate 12 is a layer 22 of adhesive,
which layer may be continuous or substantially continuous between
membrane 10 and substrate 12 (i.e. a fully-adhered system). In one
or more embodiments, the adhesive layer covers at least 20%, in
other embodiments at least 30%, in other embodiments at least 40%,
in other embodiments at least 50%, and in other embodiments at
least 60% of the surface of the substrate. In these or other
embodiments, the adhesive layer covers up to 100%, in other
embodiments less than 90%, in other embodiments less than 75%, and
in other embodiments less than 60% of the surface of the substrate.
Notably absent from the construction of one or more embodiments is
a fleece layer between membrane 10 and substrate 12. In other
words, adhesive layer 22 is adhesively bonded directly to membrane
10.
[0087] In one or more embodiments, the bond between substrate 12
and membrane 10, which is formed by adhesive layer 22, can be
quantified based upon standardized peel adhesion tests pursuant to
ASTM D1876. In one or more embodiments, the bond between membrane
10 and substrate 12 exceeds at least 1 pli, in other embodiments at
least 1.5 pli, in other embodiments at least 2.0 pli, and in other
embodiments at least 2.5 pli, where the substrate may include EPDM
membrane or, in other embodiments, a glass-reinforced, paper-faced
polyisocyanurate insulation board. Advantageously, in one or more
embodiments, the bond formed between membrane 10 and substrate 12
exceeds the pull strength limitations and/or tensile limitations of
the substrate. In other words, the substrate fails under pull force
(for example the facer pulls from the insulation or substate
boards) prior to the failure of adhesive layer 22.
[0088] In order to demonstrate the practice of the present
invention, and demonstrate the advantages of the present invention
over the prior art, the following samples were prepared and
evaluated. The examples should not, however, be viewed as limiting
the scope of the invention. The claims will serve to define the
invention.
EXAMPLES
[0089] Table I provides the ingredients employed in making each
adhesive sample, and then each sample was analyzed for static
(i.e., baseline) viscosity, and also analyzed for adhesive strength
using peel testing. Specifically, viscosity was measured using a
Brookfield visometer using a #6 spindle operating at 10 rpm at room
temperature. Peel testing was conducted using a modified ASTM D 413
test, wherein a one square foot EPDM membrane sample was adhered to
a paper-faced isocyanurate insulation board in one instance, and to
an EPDM membrane in the second instance. The substrates (i.e., the
isocyanurate board and the EPDM) were also one square foot in size
and the adhesive was applied exclusively to the substrate, and then
the EPDM sample was applied to the adhesive layer. The adhesive was
applied at an application rate of 100 square foot per gallon by
weighing the exact amount of adhesive required to cover the
substrate and then uniformly applying the adhesive to the
substrate. Testing, which was done using an Instron apparatus,
followed the procedures set forth in ASTM D 413. That is,
90.degree. peels were used for the insulation board substrate and
T-peels were used for the EPDM substrate.
[0090] Each sample was similarly prepared according to the
following mixing procedure. The polymers containing a
silicon-containing hydrolyzable terminal group, the plasticizer,
and the tackifier resin were charged to a high-speed mixer equipped
with a high-speed dispensing head and an outer scraping element
that removed material stuck to the walls of the reactor. The mixing
temperature was adjusted to 230-250.degree. F. and mixing took
place at 500 rpm for the dispenser and 9 rpm for the scraper. Once
the solid material (i.e., the tackifier) was dissolved into the
liquids, a vacuum was applied to remove any residual moisture. The
mixing conditions, temperature, vacuum, and duration under vacuum
were adjusted to achieve less than 800 ppm water. The composition
was then cooled to 80.degree. F. and mixing speeds were returned to
the original mixing speed (i.e., 500 rpm). The moisture scavenger
was then charged and initially mixed at the low speed (500 rpm),
and then the mixing speed was increased to about 1,500 rpm for the
dispensing head and 35 rpm for the scraping element. A nitrogen
blanket was applied over the mixer in an effort to inhibit the
introduction of moisture into the system. Following the addition of
the moisture scavenger, the adhesion promoter was added and mixed
using the same two-phase mixing procedure (i.e., first at 500 rpm
followed by high speed mixing of 1,500 rpm). Once the adhesion
promoter was blended into the system, the catalyst was added and
the same two-phase mixing procedure was applied. Once all of the
ingredients were added, a vacuum was again applied to the system
for a short duration in an effort to remove residual moisture
without volatilizing and removing an appreciable amount of the
ingredients added. The composition was allowed to return to room
temperature, and then samples were drawn for viscosity measurements
as well as peel adhesion tests. A nitrogen blanket was maintained
over the composition in order to avoid introduction of
moisture.
[0091] As suggested above, Table I provides the ingredients
employed in each sample, as well as the results of the peel testing
and the dynamic viscosity of the adhesives.
TABLE-US-00001 TABLE I Sample Sample 1 Sample 2 Sample 3 Sample 4
Sample 5 Sample 6 Ingredients (grams) Silyl-Terminated PolyetherI
105.00 105.00 105.00 105.00 105.00 66.57 Silyl-Terminated
Polyurethane 91.00 91.00 91.00 91.00 91.00 -- Silyl-Terminated
Polyether II -- -- -- -- -- 53.83 Silyl-Terminated Polyether III --
-- -- -- -- 65.10 Phthalate Plasticizer 98.00 98.00 98.00 98.00
98.00 106.80 Phenolic Resin 35.00 -- -- -- -- -- Moisture Scavenger
4.55 4.55 4.55 4.55 4.55 4.55 Adhesion Promoter 15.05 15.05 15.05
15.05 15.05 15.05 Catalyst 1.40 1.40 1.40 1.40 1.40 1.40 Rosin
Ester Tackifier -- 35.00 -- -- -- -- Dicyclopentadiene Tackifier --
-- 35.00 -- -- -- C.sub.5 Aliphatic Tackifier -- -- -- 35.00 -- --
C.sub.9 Aromatic Tackifier -- -- -- -- 35.00 35.00 Tests Brookfield
viscosity (cPs) 36,500 Too high to measure 14,900 9,500 14,900
6,000 Peel Test ISO substrate (pli) 5.45 3.94 1.96 3.55 6.11 1.94
EPDM substrate (pli) 2.65 1.50 2.08 2.52 2.67 1.48
Silyl-Terminated Polyether I was characterized by a number average
molecular weight of greater than about 12,000, had a polydispersity
of about 2.5, and was believed to be difunctional. Silyl-Terminated
Polyether II was characterized by a number average molecular weight
of less than about 12,000 g/mole, a polydispersity of about 1.5,
and was believed to be difunctional. Silyl-Terminated Polyether III
was characterized by a number average molecular weight of great
than about 12,000 g/mole, a polydispersity of about 2.0, and was
believed to be difunctional. The silyl-terminated polyurethane was
characterized by a number average molecular weight above about
12,000 g/mole, a polydispersity of about 2.7, and was believe to be
difunctional. The moisture scavenger was a vinyl alkoxy silane. The
adhesion promoter was an amino siloxane. The catalyst was an organo
tin catalyst.
[0092] Various modifications and alterations that do not depart
from the scope and spirit of this invention will become apparent to
those skilled in the art. This invention is not to be duly limited
to the illustrative embodiments set forth herein.
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