U.S. patent application number 13/810562 was filed with the patent office on 2013-09-05 for roofing repair system and method.
This patent application is currently assigned to 3M INNOVATIVE PROPERTIES COMPANY. The applicant listed for this patent is Martin A. Hutchinson. Invention is credited to Martin A. Hutchinson.
Application Number | 20130227909 13/810562 |
Document ID | / |
Family ID | 45004287 |
Filed Date | 2013-09-05 |
United States Patent
Application |
20130227909 |
Kind Code |
A1 |
Hutchinson; Martin A. |
September 5, 2013 |
ROOFING REPAIR SYSTEM AND METHOD
Abstract
A roofing repair system including a multi-part primer and a
water-activated overcoat composition. The multi-part primer
includes a first part including a hydroxyl-functional (meth)acrylic
(co)polymer, and a second part including a mixture of a hydrophilic
polyfunctional aliphatic polyisocyanate and a hydrophobic
polyfunctional aliphatic polyisocyanate, wherein a molar ratio of
hydroxyl functionality in the first part to isocyanate
functionality in the second part is less than 1. The
water-activated overcoat composition includes at least one compound
selected from polyketimines having amino groups attached to
secondary carbon atoms, polyenamines, and oxazolidines. In some
exemplary embodiments, the volume ratio of the multi-part primer to
the water-activated composition is from 5:1 to 7:1. In certain
exemplary embodiments, the multi-part primer is substantially free
of organic solvents. A method of using the roofing repair system to
repair the weathered surface of an elastomeric roofing membrane is
also described.
Inventors: |
Hutchinson; Martin A.;
(Yorkshire, GB) |
|
Applicant: |
Name |
City |
State |
Country |
Type |
Hutchinson; Martin A. |
Yorkshire |
|
GB |
|
|
Assignee: |
3M INNOVATIVE PROPERTIES
COMPANY
ST. PAUL
MN
|
Family ID: |
45004287 |
Appl. No.: |
13/810562 |
Filed: |
May 18, 2011 |
PCT Filed: |
May 18, 2011 |
PCT NO: |
PCT/US11/36970 |
371 Date: |
May 9, 2013 |
Related U.S. Patent Documents
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Application
Number |
Filing Date |
Patent Number |
|
|
61349235 |
May 28, 2010 |
|
|
|
Current U.S.
Class: |
52/741.1 ;
428/423.1; 428/423.3; 428/424.7; 428/424.8; 442/20; 442/43;
442/45 |
Current CPC
Class: |
C09D 133/066 20130101;
C09D 5/002 20130101; C08G 18/706 20130101; C09D 133/066 20130101;
Y10T 428/31554 20150401; C08G 18/3256 20130101; E04D 7/00 20130101;
Y10T 442/133 20150401; C09D 175/04 20130101; Y10T 442/176 20150401;
Y10T 442/172 20150401; C08G 18/721 20130101; C08F 220/343 20200201;
E04G 23/0281 20130101; Y10T 428/31551 20150401; C08F 220/343
20200201; Y10T 428/31583 20150401; Y10T 428/31587 20150401; C08G
18/6229 20130101; C09D 133/066 20130101 |
Class at
Publication: |
52/741.1 ;
442/45; 442/20; 428/424.8; 428/423.1; 428/424.7; 428/423.3;
442/43 |
International
Class: |
E04G 23/02 20060101
E04G023/02 |
Claims
1. A roofing repair system comprising: (a) a multi-part primer
comprising a first part including a hydroxyl-functional
(meth)acrylic polymer, and a second part including a mixture of a
hydrophilic polyfunctional aliphatic polyisocyanate and a
hydrophobic polyfunctional aliphatic polyisocyanate, wherein a
molar ratio of hydroxyl functionality in the first part to
isocyanate functionality in the second part is less than 1; and (b)
a water-activated overcoat composition comprising at least one
compound selected from polyketimines having amino groups attached
to secondary carbon atoms, polyenamines, and oxazolidines.
2. The roofing repair system of claim 1, wherein a volume ratio of
the multi-part primer to the water-activated overcoat composition
is from 5:1 to 7:1.
3. The roofing repair system of claim 1, wherein the multi-part
primer is substantially free of organic solvents.
4. The roofing repair system of claim 1, wherein the first part of
the multi-part primer further comprises water.
5. The roofing repair system of claim 1, wherein the multi-part
primer further comprises a catalyst, a biocide, a surfactant, a
dispersant, a rheology modifier, a particulate filler, a fibrous
material, a defoamer, a plasticizer, or a combination thereof.
6. The roofing repair system of claim 1, wherein the
hydroxyl-functional (meth)acrylic (co)polymer comprises dispersed
particles.
7. The roofing repair system of claim 1, wherein the
hydroxyl-functional (meth)acrylic (co)polymer comprises from 30 to
50% by weight of the first part of the multi-part primer.
8. The roofing repair system of claim 1, wherein a weight ratio of
hydrophilic polyfunctional aliphatic polyisocyanate to hydrophobic
polyfunctional aliphatic polyisocyanate in the second part of the
multi-part primer is at least 1:1.
9. The roofing repair system of claim 8, wherein the combined
weight of hydrophilic polyfunctional aliphatic polyisocyanate and
hydrophobic polyfunctional aliphatic polyisocyanate comprises at
least 80% by weight of the second part.
10. The roofing repair system of claim 1, wherein the
water-activated overcoat composition further comprises a
film-forming thermoplastic polymer.
11. The roofing repair system of claim 1, wherein the film-forming
thermoplastic polymer comprises a polyurethane segment.
12. The roofing repair system of claim 1, wherein the
water-activated overcoat composition further comprises a urethane
prepolymer comprising an isocyanate which has been blocked with a
phenol or an oxime.
13. The roofing repair system of claim 1, further comprising a
reinforcing layer.
14. The roofing repair system of claim 13, wherein the reinforcing
layer comprises a fiberglass mesh, a polyester fiber mesh, an
ethylene-propylene dimer elastomer, a chlorinated polyethylene
elastomer, a chlorosulfonated polyethylene elastomer, an
acrylonitrile rubber, a poly(isoburylene) elastomer, a
thermoplastic polyolefin elastomer, a polyvinyl chloride elastomer,
or a combination thereof.
15. The roofing repair system of claim 1, further comprising an
applicator selected from a brush, a pad, a squeegee, a roller, a
sprayer, or a combination thereof.
16. A method of repairing a roof, comprising the steps of: (a)
mixing together a first part comprising a hydroxyl-functional
(meth)acrylic polymer and a second part comprising a mixture of
hydrophilic polyfunctional aliphatic polyisocyanate and a
hydrophobic polyfunctional aliphatic polyisocyanate, wherein a
molar ration of hydroxyl functionality in the first part to
isocyanate functionality in the second part is less than 1, to
obtain an activated primer mixture; (b) applying the activated
primer mixture to a weathered surface of an elastomeric roofing
membrane; and (c) applying the water-activated overcoat composition
to the primer mixture on the weathered surface of the elastomeric
membrane, wherein the water-activated overcoat composition
comprises at least one compound selected from polyketimines having
amino groups attached to secondary carbon atoms, polyenamines, and
oxazolidines.
17. The method of claim 16, wherein the activated primer mixture
comprises water in an amount sufficient to obtain a non-volatile
solids content of from 30% to 50% by volume of the activated primer
mixture.
18. The method of claim 16, wherein step (b) is completed within
two hours after beginning step (a).
19. The method of claim 18, wherein step (c) is begun at least two
hours after step (b) is completed, and step (c) is completed no
more than 168 hours after beginning step (a).
20. The method of claim 16, wherein the elastomeric roofing
membrane comprises ethylene-propylene dimer elastomer, chlorinated
polyethylene elastomer, chlorosulfonated polyethylene elastomer,
acrylonitrile rubber, poly(isobutylene) elastomer, thermoplastic
polyolefin elastomer, polyvinyl chloride elastomer, or a
combination thereof.
Description
CROSS REFERENCE TO RELATED APPLICATIONS
[0001] This application claims the benefit of U.S. Provisional
Patent Application No. 61/349,235, filed May 28, 2010, which is
incorporated herein by reference in its entirety.
TECHNICAL FIELD
[0002] The present disclosure relates to a roofing repair system,
and more particularly, to a method for treating weathered
elastomeric roofing membranes to improve their weather
resistance.
BACKGROUND
[0003] A fundamental requirement for any successful roofing system,
particularly roofing systems for commercial, institutional, and
industrial buildings with flat or low-slope roofs installed, is the
ability of the roofing system to maintain its integrity and prevent
the entry of water upon weathering by exposure to sunlight and the
elements such as rain and snow. In the past, a variety of roofing
systems have been used in connection with such no- or low-slope
roofs, including, for example, metal panel roofing. Such roofing
usually consists of metal panels overlapped at their ends and
secured to the roofing decks of building structures with nails,
screws, clips or other fasteners. However, while metal panels are
relatively durable, the panels are subject to significant thermally
induced contractions and expansions due to ambient temperature
variations, a characteristic that often leads to the cracking of
such roofing, especially along the roof seams and fastener
locations, with leakage occurring as a result thereof.
[0004] In order to overcome the foregoing and other problems
associated with weather-proofing low-slope and flat roofs, single
ply roofing membranes formed from ethylene-propylene
(non-conjugated) diene monomer (EPDM) elastomers, or
chlorosulfonated ethylene (e.g. HYPALON.RTM.) elastomers, have been
exploited as roofing system components. In particular, elastomeric
single ply roofing membranes have proven to be well suited
components of roofing systems for no- or low-slope metal panel
roofs, since such elastomeric roofing membranes typically are
relatively easy to apply, have a long life, have substantial
flexibility, retain their resiliency at very low temperatures,
withstand the high temperatures frequently encountered in roofing
environments without unduly stretching or softening, and possess
good resistance to ultraviolet light.
[0005] Typically, a membrane adhesive, generally a 20-40 percent by
weight solution of elastomeric rubber in a suitable volatile
organic solvent, is applied to the interface between the roof deck
surface and the elastomeric roofing membrane in order to improve
the final adhesion of the membrane to the roof deck. Fasteners may
also be used to attach the elastomeric roofing membrane to the roof
deck.
SUMMARY
[0006] Although elastomeric roofing membranes have been
advantageously used in no- and low-slope roofing applications, such
membranes have a number of disadvantages. For example, elastomeric
roofing membranes tend to be black or dark colored and do not
exhibit a high degree of solar reflectivity, leading to increased
energy consumption and air conditioning costs during the summer
months. In addition, over time, weathering due to exposure of the
roofing membrane to solar radiation and the elements, combined with
thermally induced contractions and expansions of the roofing
membrane due to normal seasonal ambient temperature variations, may
cause weathering of the elastomeric membrane.
[0007] In fact, known single-ply membranes all eventually succumb
to the effects of extended exposure to the elements (i.e.
weathering). These effects typically manifest themselves through
degradation of the surface as it begins to oxidize, check, crack
and/or craze. Seams, whether heat-welded or glued, also eventually
begin to come apart, allowing water intrusion beneath the membrane.
Cracking of the weathered roofing membrane and the resulting water
leakage may be so severe as to require the expense of removing the
weathered roofing system down to the roof deck, and replacement
with a new roofing system.
[0008] Removal, disposal and replacement of an old single ply
roofing system is a costly process involving disposal of waste
roofing materials in a landfill. Alternatively, the weathered
roofing membrane may be repaired by patching in place. However,
attempts to patch or otherwise repair leaks in weathered
elastomeric roofing membranes may result in even more water
leakage, since merely walking on the weathered roofing membrane to
effect repairs may cause additional cracking. Furthermore, known
compositions for repairing weathered elastomeric roofing membranes
involve a tradeoff of attributes between the desired performance
results, the potential toxicity and environmental friendliness of
the materials, satisfactory shelf-life, and ease of use by
relatively unskilled users. Ideally, a simpler and more cost
effective solution has been sought.
[0009] One such solution involves the application of a liquid
roofing repair system to the entire roof to renew or repair and
thereby extend the life of the existing elastomeric roofing
membrane. Thus, in one aspect, the present disclosure describes a
roofing repair system comprising a multi-part primer and a
water-activated overcoat composition. The multi-part primer
comprises a first part including a hydroxyl-functional
(meth)acrylic (co)polymer, and a second part including a mixture of
a hydrophilic polyfunctional aliphatic polyisocyanate and a
hydrophobic polyfunctional aliphatic polyisocyanate, wherein a
molar ratio of hydroxyl functionality in the first part to
isocyanate functionality in the second part is less than 1. The
water-activated overcoat composition comprises at least one
compound selected from polyketimines having amino groups attached
to secondary carbon atoms, polyenamines, and oxazolidines.
[0010] In some exemplary embodiments of the foregoing roofing
repair system, the volume ratio of the multi-part primer to the
water-activated overcoat composition is from 5:1 to 7:1. In certain
exemplary embodiments, the multi-part primer is substantially free
of organic solvents. In further exemplary embodiments, the first
part of the multi-part primer further comprises water.
[0011] In additional exemplary embodiments according to any of the
foregoing roofing repair systems, the multi-part primer further
comprises a catalyst, a biocide, a surfactant, a dispersant, a
rheology modifier, a defoamer, a plasticizer, a particulate filler,
a fibrous material, or a combination thereof. In some exemplary
embodiments, the hydroxyl-functional (meth)acrylic (co)polymer
comprises dispersed particles. In certain exemplary embodiments,
the hydroxyl-functional (meth)acrylic (co)polymer comprises from 30
to 50% by weight of the first part of the multi-part primer.
[0012] In additional exemplary embodiments of any of the foregoing
roofing repair systems, the weight ratio of hydrophilic
polyfunctional aliphatic polyisocyanate to hydrophobic
polyfunctional aliphatic polyisocyanate in the second part of the
multi-part primer is at least 1:1. In some exemplary embodiments,
the combined weight of hydrophilic polyfunctional aliphatic
polyisocyanate and hydrophobic aliphatic polyisocyanate comprises
at least 80% by weight of the second part.
[0013] In other exemplary embodiments of any of the foregoing
roofing repair systems, the water-activated overcoat composition
further comprises a film-forming thermoplastic polymer. In some
exemplary embodiments, the film-forming thermoplastic polymer
comprises a polyurethane segment. In certain exemplary embodiments,
the water-activated overcoat composition further comprises a
urethane prepolymer comprising an isocyanate which has been blocked
with a phenol or an oxime.
[0014] In additional exemplary embodiments, the roofing repair
systems of any of the foregoing embodiments further comprise a
reinforcing layer. In some exemplary embodiments, the reinforcing
layer comprises a fiberglass mesh, a polyester fiber mesh, an
ethylene-propylene dimer elastomer membrane, a chlorinated
polyethylene elastomer membrane, a chlorosulfonated polyethylene
elastomer membrane, an acrylonitrile-rubber membrane, a
poly(isobutylene) elastomer membrane, a thermoplastic polyolefin
elastomer membrane, a poly(vinyl) chloride elastomer membrane, or a
combination thereof. In certain exemplary embodiments, the roofing
repair systems according to any of the preceding embodiments
further comprise an applicator selected from a brush, a pad, a
squeegee, a roller, a sprayer, or a combination thereof.
[0015] In another aspect, the disclosure describes a method of
using the roofing repair system according to any one of the
preceding embodiments, the method comprising the steps of: (a)
mixing together the first part and the second part of the
multi-part primer to obtain an activated primer mixture, (b)
applying the activated primer mixture to a weathered surface of an
elastomeric roofing membrane, and (c) applying the water-activated
overcoat composition to the primer mixture on the weathered surface
of the elastomeric membrane.
[0016] In some exemplary embodiments of the foregoing method, the
activated primer mixture comprises water in an amount sufficient to
obtain a non-volatile solids content of from 30% to 50% by volume
of the activated primer mixture. In certain exemplary embodiments,
step (b) is completed within two hours after beginning step (a). In
further exemplary embodiments, step (c) is begun at least two hours
after step (b) is completed, and step (c) is completed no more than
168 hours after beginning step (a). In additional exemplary
embodiments, the elastomeric roofing membrane comprises
ethylene-propylene dimer elastomer, chlorinated polyethylene
elastomer, chlorosulfonated polyethylene elastomer,
acrylonitrile-rubber, poly(isobutylene) elastomer, thermoplastic
polyolefin elastomer, polyvinyl chloride elastomer, or a
combination thereof.
[0017] In some exemplary embodiments, the roofing repair system and
method of the present disclosure provides a number of unexpected
results and advantages. In exemplary embodiments, the roofing
repair system and method uses a water-based multi-part primer that
has low toxicity, is environmentally benign, has excellent shelf
stability, is easy to apply, and, when activated, has a
sufficiently low viscosity to permit penetration and good adhesion
of the primer layer to a weathered surface of an elastomeric
roofing membrane.
[0018] In further exemplary embodiments, the roofing repair system
includes a water-activated overcoat composition that reacts with
(i.e. covalently bonds to) the at least partially cured activated
primer layer on the weathered surface of the elastomeric roofing
membrane, thereby promoting good interlayer adhesion between the
overcoat layer and the primer layer, as well as good adhesion of
the roofing repair system to the weathered surface of the
elastomeric roofing membrane. Moreover, the roofing repair system
may be formulated to contain little or no volatile organic
solvents, is typically easy to apply by relatively unskilled works
using a variety of application methods (e.g. brushing, spraying,
and the like), and generally exhibits excellent extended shelf
stability. The roofing repair system thus offers an effective and
relatively low cost solution to the problem of renewing,
refurbishing, or repairing weathered single ply roofing surfaces
which employ elastomeric roofing membranes, particularly EPDM or
HYPALON.RTM. elastomeric roofing membranes.
[0019] Various aspects and advantages of exemplary embodiments of
the present disclosure have been summarized. The above Summary is
not intended to describe each illustrated embodiment or every
implementation of the exemplary embodiments of the present
disclosure. The Detailed Description that follows more particularly
exemplifies certain presently preferred embodiments using the
principles disclosed herein.
DETAILED DESCRIPTION
Glossary
[0020] As used throughout this application:
[0021] the term "continuous" refers to covering the surface of the
substrate with virtually no discontinuities or gaps in the areas
where the covering is applied;
[0022] the term "hydrophilic" refers to a material, component or
region which is water soluble, water miscible or water
dispersible;
[0023] the term "hydrophobic" refers to a material, component or
region which is not appreciably soluble in water and which does not
substantially disperse when added to water in the absence of other
additives or components;
[0024] the term "surfactant" describes a molecule having both
hydrophilic (e.g. polar) and hydrophobic (e.g. non-polar) regions
on the same molecule and which is capable of reducing the surface
tension of an aqueous mixture;
[0025] the term "dispersant" describes a molecule, which may be a
surfactant, used to prepare a liquid/liquid or solid/liquid
dispersion by imparting phase stability for a period of time
sufficient for the dispersion to be used for its intended
purpose;
[0026] the term "(co)polymer" means a homopolymer or copolymer;
[0027] the term "(meth)acrylic (co)polymer" means a (co)polymer
obtained by polymerizing one or more alkyl ester monomers formed by
reaction of an alkyl alcohol with acrylic acid or methacrylic
acid.
[0028] the term "polyfunctional aliphatic polyisocyanate" refers to
a (co)polymer comprising two or more isocyanate groups, which may
be blocked isocyanate groups, and based on hexamethylene
diisocyanate.
[0029] the term "polyurethane" includes any polymeric material that
has at least one polyurethane segment;
[0030] the term "polyurethane segment" refers to at least two
urethane and/or urea groups that are connected by an organic
group;
[0031] the term "single ply roofing" refers to a single layer
elastomeric roofing membrane which may be ballasted, fully-adhered,
and/or mechanically attached installations;
[0032] the term "elastomeric roofing membrane" means a
pre-manufactured flexible or semi-flexible sheet formed with
non-vulcanized and/or vulcanized elastomers, such as
ethylene-propylene diene monomer (EPDM) elastomers, poly(vinyl)
chloride (PVC) elastomers, chlorinated polyethylene (CPE)
elastomers, chlorosulfonated polyethylene (CSPE) elastomers,
acrylonitrile-rubber (NBR) elastomers, poly(isobutylene) (PIB)
elastomers, thermoplastic polyolefin (TPO) elastomers, and the
like.
[0033] In general, this disclosure describes a roofing repair
system including a multi-part primer suitable for promoting the
adhesion of a water-activated overcoat composition to weathered
roofing membranes such as, for example, single ply roofing
membranes formed from ethylene-propylene diene monomer (EPDM) or
chlorosulphonated ethylene (e.g. HYPALON.RTM. ex DuPont).
[0034] Adhesion of roofing repair materials to weathered
elastomeric roofing membranes, which tend to have a friable surface
particularly after exposure to ponding water conditions, has been
problematic. None of the known roofing repair systems for use on
weathered elastomeric roofing membranes are believed to include a
water-based primer have the capability of binding to both the
weathered elastomeric membrane material and the subsequently
applied overcoat composition by anything other than physical
means.
[0035] Thus, in exemplary embodiments, the present disclosure
provides a roofing repair system comprising a multi-part primer and
a water-activated overcoat composition which is covalently bonded
to the primer after application to the weathered surface of an
elastomeric roofing membrane. In other exemplary embodiments, the
present disclosure provides a method of applying the roofing repair
system to a weathered surface of an elastomeric roofing
membrane.
Roofing Repair System
[0036] In one aspect, the present disclosure describes a roofing
repair system including a multi-part reactive primer which can be
activated prior to application to a weathered elastomeric roofing
membrane, thereby producing in situ an isocyanate-functional
(meth)acrylate-urethane (co)polymer having excess unreacted
isocyanate groups. The activated primer is sufficiently fluid to
penetrate into the weathered surface of an elastomeric roofing
membrane, thereby promoting good adhesion between the primer and
the elastomeric roofing membrane.
[0037] After drying of the coated primer, a water-activated
overcoat composition is applied over and in contact with the at
least partially cured primer. Upon activation by exposure to water
(e.g. moisture in the air), the water-activated overcoat
composition reacts with water to provide a pre-polymer having amine
and/or hydroxyl functional groups, which undergo chemical reaction
with the excess unreacted isocyanate groups in the primer to form
urea or urethane chemical bonds to the primer, thereby promoting
good interlayer adhesion between the activated overcoat layer and
the at least partially cured primer layer.
Multi-Part Primer
[0038] The multi-part primer comprises a first part including a
hydroxyl-functional (meth)acrylic (co)polymer, and a second part
including a mixture of a hydrophilic polyfunctional aliphatic
polyisocyanate and a hydrophobic polyfunctional aliphatic
polyisocyanate, wherein the molar ratio of hydroxyl functionality
in the first part to isocyanate functionality in the second part is
less than 1. In certain presently preferred embodiments, the molar
ratio of hydroxyl functionality in the first part to isocyanate
functionality in the second part is less than 0.9, more preferably
less than 0.75, even more preferably less than 0.5, 0.4, 0.3, 0.2
or 0.1. In some of these embodiments, the molar ratio of hydroxyl
functionality in the first part to isocyanate functionality in the
second part is at least 0.1, 0.2, 0.3, 0.4, 0.5, 0.6, 0.7, or even
0.8.
[0039] In further exemplary embodiments, the volume ratio of the
multi-part primer to the water-activated overcoat composition is
from 1:1 to 12:1, more preferably from 2:1 to 10:1, even more
preferably from 2:1 to 10:1, 3:1 to 9:1, 4:1 to 8:1, 5:1 to 7:1, or
most preferably 6:1.
[0040] In some exemplary embodiments, the roofing repair system
provides the multi-part primer and the water-activated overcoat
composition in pre-determined amounts at a volume ratio of from 2:1
to 10:1, more preferably 3:1 to 9:1, 4:1 to 8:1, 5:1 to 7:1, or
most preferably 6:1.
[0041] In certain exemplary embodiments, the multi-part primer is
substantially free of organic solvents. In such embodiments, the
multi-part primer preferably includes no more than 10%, 9%, 8%, 7%,
6%, 5%, 4%, 3%, 2%, 1%, or 0% by weight of an organic solvent based
on the total weight of the multi-part primer.
[0042] In some particular exemplary embodiments, at least the first
part of the multi-part primer is substantially free of organic
solvents. In such embodiments, the roofing repair system components
preferably include no more than 10%, 9%, 8%, 7%, 6%, 5%, 4%, 3%,
2%, 1%, or 0% by weight of an organic solvent based on the weight
of the first part of the multi-part primer.
[0043] In certain presently preferred embodiments, the activated
multi-part primer is waterborne, that is, comprising at least 50%,
more preferably at least 60%, even more preferably at least 70% or
even 80% water, based on the weight of the activated multi-part
primer. In further embodiments, the activated multi-part primer
comprises no more than 90%, more preferably no more than 85%, even
more preferably about 75% or even 55-65% by weight of water based
on the weight of the activated multi-part primer.
[0044] First Part--Hydroxyl-Functional (Meth)Acrylic
(Co)Polymer
[0045] The first part of the primer comprises at least one
hydroxyl-functional (meth)acrylic (co)polymer. In some exemplary
embodiments, the hydroxyl-functional (meth)acrylic (co)polymer
comprises a solution polymer, for example, those described in U.S.
Pat. Nos. 6,001,931 and 6,103,849, each of which is incorporated
herein by reference in its entirety. In certain presently preferred
exemplary embodiments, the hydroxyl-functional (meth)acrylic
(co)polymer comprises dispersed particles, for example, those
described in U.S. Patent Application Publication Nos. 2008/0214766
and 2009/0105409, each of which is incorporated herein by reference
in its entirety. In some exemplary embodiments, a combination of a
hydroxyl-functional (meth)acrylic solution (co)polymer and
hydroxyl-functional (meth)acrylic dispersed particles may be
advantageously employed. In such embodiments, the weight ratio of
hydroxyl-functional (meth)acrylic (co)polymer in the solution to
hydroxyl-functional (meth)acrylic (co)polymer particles in the
dispersion may be advantageously varied over a wide range, for
example, from 1:9, 1:5; 1:4; 1:3: 1:2, 1:1, 2:1, 3:1, 4:1, 5:1, or
even 9:1.
[0046] In further presently preferred embodiments, the dispersed
particles comprise the hydroxyl-functional (meth)acrylic
(co)polymer, and the dispersion medium comprises water. (i.e. the
first part of the multi-part primer comprises a waterborne
dispersion). Presently preferred waterborne hydroxyl-functional
(meth)acrylic (co)polymers in dispersed form are sold under the
trade name BAYHYDROL (available from Bayer Material Science LLC,
Pittsburgh, Pa.). A presently preferred waterborne
hydroxyl-functional (meth)acrylic (co)polymer in dispersed is
BAYHYDROL A 145 (available from Bayer Material Science LLC,
Pittsburgh, Pa.), a dispersion of a hydroxyl-functional acrylic
polymer (43-47% w/w) in water.
[0047] In certain exemplary embodiments, the hydroxyl-functional
(meth)acrylic (co)polymer comprises at least 20%, more preferably
at least 30%, even more preferably at least 40%, or even 50% by
weight of the first part of the multi-part primer. In further
exemplary embodiments, the hydroxyl-functional (meth)acrylic
(co)polymer comprises from 20% to 70%, more preferably from 25% to
60%, even more preferably from 30% to 50% by weight of the first
part of the multi-part primer.
[0048] In further exemplary embodiments of the foregoing roofing
repair systems, the first part of the multi-part primer further
comprises water. Preferably, at least the first part of the
multi-part primer is waterborne, more preferably a waterborne
dispersion as noted above. In some presently preferred embodiments,
the first part of the multi-part primer comprises water, and is
substantially free of organic solvents. In such embodiments, the
first part of the multi-part primer preferably includes no more
than 10%, 9%, 8%, 7%, 6%, 5%, 4%, 3%, 2%, 1%, or 0% by weight of an
organic solvent.
[0049] Second Part--Polyfunctional Aliphatic Polyisocyanates
[0050] The second part of the multi-part primer comprises a mixture
of a hydrophilic polyfunctional aliphatic polyisocyanate and a
hydrophobic polyfunctional aliphatic polyisocyanate. Exemplary
aliphatic polyisocyanates are described in U.S. Pat. No. 4,619,999,
which is incorporated herein by reference in its entirety.
Aliphatic polyisocyanates based on hexamethylene diisocyanate
(HMDI) are presently preferred in order to obtain the benefits of
improved light stability for the applied roofing repair system, in
contrast to aromatic polyisocyanates based on aromatic isocyanates,
such as m-tetramethylenexylene diisocyanate (TMXDI) and isophorone
isocyanate (IPI). However, small amounts, for example, less than
15%, less than 10%, less than 5%, or even less than 1% by weight of
the second part of the multi-part primer may comprise an aromatic
polyisocyanate, although this is not presently preferred.
[0051] Preferably, the polyisocyanate compound employed contains
two isocyanate groups, however, polyisocyanate compounds containing
greater than two isocyanate groups may also be used, for example,
polyisocyanates based on ethylene diisocyanate,
3-isocyanatomethyl-3,5,5,-trimethylcyclohexylisocyanate (IPDI), and
bis(4-isocyanateocyclohexyl)methane. A mixture or a blend of more
than one polyisocyanate compound may also be employed, for example,
an aromatic polyisocyanate, preferably in combination with at least
one aliphatic isocyanate based on hexamethylene diisocyanate (HMDI)
as a major component of the second part of the multi-part
primer.
[0052] In some exemplary embodiments, unblocked aliphatic
polyisocyanates containing from about 6 to 100 carbon atoms may be
used. Blocked aliphatic isocyanates may be advantageously used in
some exemplary embodiments. Exemplary blocked isocyanates are
described in, for example, U.S. Pat. Nos. 5,246,557; 5,352,755; and
6,843,933, the disclosures of which are incorporated herein by
reference in their entireties. If used in the multi-part primer,
the blocked isocyanate preferably exhibits a low de-blocking
temperature, preferably less than 110.degree. C., more preferably
less than 100.degree. C., even more preferably less than 90.degree.
C.
[0053] Hydrophilic Polyfunctional Aliphatic Isocyanate
[0054] Suitable hydrophilic polyisocyanates include water miscible
or water dispersible aliphatic polyisocyanates sold under the trade
names BAYHYDUR.RTM. 304, BAYHYDUR.RTM. 305, BAYHYDUR.RTM. 3100,
BAYHYDUR.RTM. XP 2451, BAYHYDUR.RTM. XP 2487/1, BAYHYDUR.RTM.
XP2547, BAYHYDUR.RTM. XP 2655, and BAYHYDUR.RTM. XP 2700 (available
from Bayer Material Science LLC, Pittsburgh, Pa.). BAYHYDUR.RTM. XP
2487/1, a hydrophilic, water dispersible poly-functional aliphatic
polyisocyanate based on hexamethylene diisocyanate, is presently
preferred.
[0055] In some exemplary embodiments, the hydrophilic
polyisocyanate may be advantageously selected to be a waterborne
aliphatic polyisocyanate, such as sold under the trade name Easaqua
XD 401, Easaqua XD 501, Easaqua XD 502, Easaqua XD 803, Easaqua WT
2102, Easaqua WAT, Easaqua WAT-1, Easaqua X WAT-3, and Easaqua X
WAT-4 (all available from Perstop, Inc., Freeport, Tex.).
[0056] Hydrophobic Polyfunctional Aliphatic Isocyanate
[0057] Suitable hydrophobic aliphatic polyisocyanates include
blocked aliphatic polyisocyanates based on hexamethylene
diisocyanate, for example, those sold under the trade names
DESMODUR BL 3175A, DESMODUR 3272 MPA, DESMODUR BL 3370 MPA,
DESMODUR 3475 BA/BN, DESMODUR 3575 MPA/SN, DESMODUR BL 5375,
DESMODUR DA/1, DESMODUR DN, and DESMODUR N 3600. DESMODUR N 3600, a
hydrophobic, solvent-free blocked isocyanate based on hexamethylene
diisocyanate, is presently preferred.
[0058] In additional exemplary embodiments of any of the foregoing
roofing repair systems, the weight ratio of hydrophilic
polyfunctional aliphatic polyisocyanate to hydrophobic
polyfunctional aliphatic polyisocyanate in the second part of the
multi-part primer is at least 1:1, 2:1, or even 3:1. In some of
these embodiments, the weight ratio of hydrophilic polyfunctional
aliphatic polyisocyanate to hydrophobic polyfunctional aliphatic
polyisocyanate in the second part of the multi-part primer is at
most 4:1, 3:1, 2:1 or even 1:1.
[0059] In certain exemplary embodiments, the combined weight of
hydrophilic polyfunctional aliphatic polyisocyanate and hydrophobic
polyfunctional aliphatic polyisocyanate comprises at least 50%,
60%, 70% or even 80% by weight of the second part. In some of these
embodiments, the combined weight of hydrophilic polyfunctional
aliphatic polyisocyanate and hydrophobic polyfunctional aliphatic
polyisocyanate comprises at most 90%, 85%, 75%, 65% or even 55% by
weight of the second part.
Water-Activated Overcoat Composition
[0060] The water-activated overcoat composition comprises at least
one compound selected from polyketimines having amino groups
attached to secondary carbon atoms, polyenamines, and oxazolidines.
Suitable compounds are described in U.S. Pat. Nos. 4,118,376 and
6,103,849, the disclosures of which are each incorporated herein by
reference in their entirety.
[0061] Exemplary presently preferred water-activated overcoat
compositions comprising oxazolidines are available under the trade
names SCOTCHKOTE.TM. Advanced CSM Liquid Roof Membrane,
SCOTCHKOTE.TM. Premier EC Liquid Roof Membrane, SCOTCHKOTE.TM.
Premier UV Liquid Roof Membrane, SCOTCHKOTE.TM. Premier Plus EC
Liquid Roof Membrane, and SCOTCHKOTE.TM. Premier Plus UV Liquid
Roof Membrane (all available from 3M Company, St. Paul, Minn.).
[0062] Other optional components may additionally be included in
the water-activated overcoat composition. Particularly preferred
additional optional components include one or more thermoplastic
polymers, and radiation reflective particles, as described further
below.
[0063] Optional Film-Forming Thermoplastic Polymer
[0064] In some exemplary embodiments of any of the foregoing
roofing repair systems, the water-activated overcoat composition
further comprises a film-forming thermoplastic polymer. Preferred
film-forming thermoplastic polymers are substantially water
insoluble, but are more preferably water miscible or water
dispersible. In some exemplary embodiments, the film-forming
thermoplastic polymer comprises a polyurethane segment. For
example, one or more of any of the foregoing disclosed hydrophilic
polyisocyanates and/or hydrophobic polyisocyanates may be added to
the water-activated overcoat composition to form a film-forming
thermoplastic polymer comprising a polyurethane segment.
[0065] In certain exemplary embodiments, the water-activated
overcoat composition further comprises a urethane prepolymer
comprising an isocyanate which has been blocked with a phenol or an
oxime. Exemplary urethane prepolymers comprising an isocyanate
which has been blocked with a phenol or an oxime are described, for
example, in U.S. Pat. No. 6,103,849, which was previously
incorporated by reference in its entirety.
[0066] In some particularly preferred embodiments, an optional
additional top or outer layer of the roofing repair system may be
applied over (preferably applied directly to) the at least
partially cured water-activated overcoat composition in order to
provide additional protection from exposure to solar radiation, for
example, ultraviolet (UV). Exemplary presently preferred top or
outer layer compositions suitable to impart UV radiation protection
are available under the trade names SCOTCHKOTE.TM. Premier UV
Liquid Roof Membrane, and SCOTCHKOTE.TM. Premier Plus UV Liquid
Roof Membrane (available from 3M Company, St. Paul, Minn.).
Preferably, the optional additional top or outer layer of the
roofing repair system comprises radiation reflective particles that
provide a solar reflective surface, as described further below.
[0067] Radiation Reflective Particles
[0068] In some exemplary embodiments, the multi-part primer and/or
water-activated overcoat composition and/or an optional top or
outer layer of the roofing repair system comprise radiation
reflective particles, so that the roofing repair system provides a
solar reflective surface when applied to a weathered elastomeric
roofing membrane and dried to form a film. In certain exemplary
embodiments, the solar reflective surface may exhibit a direct
solar reflectance of at least 20%, more preferably at least 30%,
even more preferably at least 40%, 50%, 60% or still more
preferably at least 70% or even 80% or higher.
[0069] By direct solar reflectance is meant that fraction reflected
of the incident solar radiation received on a surface perpendicular
to the axis of the radiation within the wavelength range of 300 to
2500 nm as computed according to the following modification of the
ordinate procedure defined in ASTM Method G159. A spreadsheet
(available upon request from Lawrence Berkeley Laboratory,
Berkeley, Calif.), combining the direct and hemispherical Solar
Irradiance Air Mass 1.5 data from ASTM method G159 may be used to
compute interpolated irradiance data at 5 nm intervals in the
region of interest. The 5 nm interval data may be used to create
weighting factors by dividing the individual irradiances by the
total summed irradiance from 300 to 2500 nm. The weighting factors
may then be multiplied by the experimental reflectance data taken
at 5 nm intervals to obtain the direct solar reflectance at those
wavelengths.
[0070] In certain exemplary embodiments, the radiation reflective
particles may be selected to include light reflective particles
reflective to visible light, that is, actinic radiation having a
wavelength from about 400 nm to about 700 nm. In one presently
preferred embodiment, the light reflective particles comprise
aluminum metal, more preferably aluminum metal particulates, even
more preferably dispersed aluminum flake pigments. Suitable
dispersed aluminum flake pigments are available under the trade
name SPARKLE SILVER (available from Silberline Manufacturing
Company, Tamaqua, Pa.). These dispersed aluminum flake pigments are
available at different average particle sizes and in varying
concentrations dispersed in a carrier solvent.
[0071] In other exemplary embodiments, the multi-part primer and/or
water-activated overcoat composition and/or an optional top or
outer layer of the roofing repair system may additionally or
alternatively comprise radiation reflective particles reflective to
infrared (IR) radiation, thereby forming a solar reflective
surface. Thus, in some exemplary embodiments, the solar reflective
surface exhibits a direct solar reflectance of at least about 20%,
more preferably at least 25%, even more preferably at least 30%,
40%, 50% or still more preferably at least 60% or even 75% or
higher at substantially all points in the wavelength range between
770 and 2500 nm as computed according to the foregoing modification
of the ordinate procedure defined in ASTM Method G159, except that
the total summed irradiance is determined from 770 to 2500 nm
instead of from 300 to 2500 nm.
[0072] In one presently preferred embodiment, the radiation
reflective particles may be white pigments, such as titanium
dioxide, which may be surface treated using methods known to those
skilled in the art to improve resistance to "yellowing" when used
with polymeric binder systems subject to photocatalytic
degradation.
[0073] In some exemplary embodiments, colored pigments that exhibit
enhanced reflectivity in the near infrared (NIR) portion of the
solar spectrum as compared to previous colorants, may be
advantageously used. The NIR portion comprises approximately 50-60%
of the sun's incident energy. Improved reflectivity in the NIR
portion of the solar spectrum leads to significant gains in energy
efficiency and such pigments are useful in some embodiments of the
present invention.
[0074] Thus, in certain exemplary presently preferred embodiments,
the radiation reflective particles may be colored pigments that
have enhanced NIR reflectivity, and are thus both colored and NIR
reflective. Such pigments include, for example, 10415 Golden
Yellow, 10411 Golden Yellow, 10364 Brown, 10201 Eclipse Black,
V-780 IR BRN Black, 10241 Forest Green, V-9248 Blue, V-9250 Bright
Blue, F-5686 Turquoise, 10202 Eclipse Black, V-13810 Red, V-12600
IR Cobalt Green, V-12650 Hi IR Green, V-778 IR Brown-Black, V-799
Black, and 10203 Eclipse Blue Black (all available from Ferro
Corp., Cleveland, Ohio); and Yellow 193, Brown 156, Brown 8, Brown
157, Green 187B, Green 223, Blue 424, Black 411, Black 10C909 (all
available from Shepherd Color Co., Cincinnati, Ohio). Additional
colored pigments of interest, some displaying enhanced infrared
light reflectivity, are discussed in Sliwinski et al., U.S. Pat.
Nos. 6,174,360 and 6,454,848, both of which are incorporated herein
by reference in their entirety.
[0075] In some presently preferred embodiments, the resulting
direct solar reflectance or radiation reflectivity of the solar
reflective surface obtained using the roofing repair system of the
present disclosure may exceed 20% at the wavelengths of interest.
The phrase solar reflectivity and direct solar reflectance are used
interchangeably in the present application. Solar reflectivity
values of at least 25% meet the present solar reflectivity standard
set forth by the U.S. Environmental Protection Agency (EPA) under
the program entitled "Energy Star". The EPA permits manufacturers
to use the designation "Energy Star" for those roofing products
that meet certain energy specifications. This "Energy Star"
designation is a desirable designation to place on roofing
products.
[0076] In general, the amount of radiation reflective particles
added to the water-activated overcoat composition and/or optional
top or outer layer of the roofing repair system may vary with the
particular material. In some exemplary embodiments, the
concentration is preferably no more than about 30% w/w, more
preferably no more than 25% by weight, more preferably no more than
20% by weight, and even more preferably no more than 15% by weight
of the total weight of the water-activated overcoat composition
and/or an optional top or outer layer of the roofing repair system.
In certain exemplary embodiments, the radiation reflective
particles comprise 1-30%, more preferably 2.5-25%, even more
preferably 5-20% by weight of the water-activated overcoat
composition and/or optional top or outer layer of the roofing
repair system.
Optional Additives
[0077] In additional exemplary embodiments, the multi-part primer
and/or water-activated overcoat composition and/or optional top or
outer layer of the roofing repair system may further comprise an
additive selected from a catalyst, a biocide, a surfactant, a
dispersant, a rheology modifier, a defoamer, a plasticizer, a
particulate filler, a fibrous material, or a combination thereof.
In some presently preferred embodiments, the additive is added to
the first part of the multi-part primer.
[0078] Catalysts
[0079] In some exemplary embodiments, an optional catalyst may be
added to the multi-part primer, preferably to catalyze reaction of
the hydroxyl-functional (meth)acrylic (co)polymer with the
hydrophilic polyfunctional aliphatic polyisocyanate and the
hydrophobic polyfunctional aliphatic polyisocyanate, for example,
by forming a urethane linkage.
[0080] Useful catalysts include metallic complex catalysts include
Group I metal salts, i.e., alkali salts, of carboxylic acids such
as stearates, octoates and phenoxides, as well as Lewis Acids such
as tin salts, zinc chloride, ferric chloride, tin octoate, and
alkali salts of phenoxides, for example, potassium
p-nonylphenoxide. Presently preferred catalysts include metal
soaps, particular soaps of tin, such as dibutyl tin dilaurate
(DBTDL).
[0081] Generally, the catalyst should be employed in a
catalytically effective amount, such as an amount from about 1% to
about 10% by weight, more preferably from about 2.5% to about 7.5%
by weight, even more preferably from about 4% by weight to about 6%
by weight, based on the total weight of the activated multi-part
primer.
[0082] Biocides
[0083] In some exemplary embodiments, one or more components of the
roofing repair system includes a biocide. Preferably, the biocide
is an organic biocide, more preferably an organic algaecide. In
some exemplary presently preferred embodiments, the organic
algaecide is selected from the class consisting of
hexahydro-1,3,5-tris(2-hydroxyethyl)-s-triazine,
hexahydro-1,3,5-triethyl-s-triazine,
2-(tert-butylamino)-4-chloro-6-(ethylamino)-S-triazine,
tetrahydro-3,5-dimethyl-2H-1,3,5-thiadiazine-2-thione,
3-iodo-2-propyl butyl carbamate, sodium dimethyldithiocarbamate,
disodium ethylene bisdithiocarbamate, disodium
cyanodithioimidocarbamate, potassium N-methyldithiocarbamate,
potassium dimethyldithiocarbamate,
2,2-dibromo-3-nitrilopropionamide, 2,2-dibromo-2-nitroethanol,
2-bromo-2-nitro-1,3-propanediol,
4,5-dichloro-2-n-octyl-4-isothiazolin-3-one,
2-methyl-2,3-dihydroisothiazol-3-one,
5-chloro-2-methyl-4-isothiazolin-3-one,
2-n-octyl-4-isothiazolin-3-one, chloroallyl-3,5,7-azoniaadamantane
chloride, tetrakishydroxymethyl phosphonium sulfate,
poly[oxyethylene(dimethyliminio)ethylene-(dimethyliminio)ethylene
dichloride], didecyl dimethyl ammonium chloride, and
dodecylguanidine hydrochloride.
[0084] Typically, the biocide may be added in an amount of at least
0.01% to at most 5.0% by weight, more preferably at least 0.02% to
at most 3% by weight, even more preferably at least 0.05% and at
most 2.5% by weight, based on the total weight of the multi-part
primer.
[0085] Surfactants and Dispersants
[0086] In some exemplary embodiments, an optional surface active
agent (i.e. surfactant) or dispersant may be added to the
multi-part primer. Suitable surfactants include anionic
surfactants, cationic surfactants, zwitterionic surfactants,
nonionic surfactants, and mixtures thereof. Exemplary anionic
surfactants include, for example, long chain carboxylic and
sulphonic acids. Exemplary cationic surfactants include, for
example, the hydrochlorides of fatty diamines, imidazolines,
ethoxylated amines, amido-amines and quaternary ammonium compounds.
Exemplary non-ionic surfactants include, for example, ethoxylated
alkyl phenols, ethoxylated alcohols and ethoxylated sorbitan
esters. Fluorochemical surfactants may also be used advantageously.
A presently preferred surfactant is sold under the trade name
Surfynol.RTM. 104E (available from Air Products and Chemicals,
Inc., Allentown, Pa.).
[0087] Typically, the surfactant may be added in an amount of at
least 0.01% to at most 5.0% by weight, more preferably at least
0.02% to at most 3% by weight, even more preferably at least 0.05%
and at most 2.5% by weight, based on the total weight of the
multi-part primer.
[0088] Rheology Modifiers
[0089] In some exemplary embodiments, the viscoelastic properties
of the multi-part primer may be further improved using an optional
rheology modifier. Plasticizers (described further below) may, in
some embodiments, be used to modify the rheological properties of
the multi-part primer to obtain a desired consistency when
activated.
[0090] In some exemplary embodiments, the multi-part primer may
further comprise a thixotrope. Such thixotropes are well known to
those skilled in the art and include alumina, limestone, talc,
kaolin clay, zinc oxides, sulfur oxides, calcium carbonate,
Perlite.RTM., slate flour, cyclodextrin and the like. The
thixotrope may be added to the adhesive of composition in a
sufficient amount to give the desired rheological properties.
[0091] Preferably the thixotrope, if used, is present in an amount
of about 0.1 part by weight or greater, more preferably about 0.5
part by weight or greater, even more preferably about 1.0 part by
weight or greater based on the weight of the first part of the
multi-part primer. Preferably the optional thixotrope is present in
an amount of about 10 parts by weight or less, more preferably
about 5 parts by weight or less, even more preferably about 2.5
parts by weight or less based on the weight of the first part of
the multi-part primer.
[0092] In other exemplary embodiments, an optional gelling agent
may be added to the multi-part primer. The gelling agent may, in
some embodiments, function both as a filler and a viscosity control
agent, by forming a three-dimensional network upon mixing with the
bituminous material. Suitable gelling agents include clays such as,
for example, attapulgite, bentonite or sepiolite clays, although
other similar functioning materials are probably acceptable and are
intended to come within the scope of this disclosure. In certain
exemplary embodiments, especially for high performance construction
materials, the multi-part primer may contain an optional polymer or
ground up rubber or some other "plastic" like material which can be
dispersed or dissolved in the asphalt to swell and/or gel and
thereby form a matrix. When such gelling agents are added,
conventional techniques may be used to blend the gelling agent with
the base asphalt.
[0093] In some exemplary embodiments, the multi-part primer
preferably comprises at least 0.01 to at most 5.0 wt. % of the
rheology modifier, more preferably at least 0.02% to at most 2.5%,
even more preferably at least 0.05% and at most 1% based on the
total weight of the multi-part primer.
[0094] Defoamers
[0095] In some exemplary embodiments, a defoamer or an anti-foaming
agent that reduces and/or hinders the formation of foam may be
included in one or more component of the roofing repair system.
Suitable defoamers are known in the art, and include, for example,
silicone (co)polymers and/or poly(ethylene oxide)-poly(propylene
oxide) copolymers. One particularly useful defoamer is available
under the trade name Surfynol.RTM. DF-178 (available from Air
Products and Chemicals, Inc., Allentown, Pa.).
[0096] Plasticizers
[0097] The multi-part primer may further comprise a plasticizer.
Suitable plasticizers are common plasticizers useful in
polyurethane adhesive applications and well known to those skilled
in the art. Suitable plasticizers are well known in the art and
presently preferred plasticizers include alkyl phthalates such as
dioctylphthalate or dibutylphthalate, partially hydrogenated
terpene commercially available as "HB-40", trioctyl phosphate,
epoxy plasticizers, toluene-sulfamide, chloroparaffins, adipic acid
esters, castor oil, toluene and alkyl naphthalenes.
[0098] If used, the plasticizer is preferably present in an amount
sufficient to plasticize one or more of the hydrophilic
polyfunctional aliphatic polyisocyanate, the hydrophobic
polyfunctional aliphatic, or the weathered surface of the
elastomeric roofing membrane to which the primer is applied. The
plasticizer can be added to the first part or the second part of
the multi-part primer, although preferably the plasticizer is added
to the second part of the multi-part primer. Preferably the
plasticizer is present in the second part of the multi-part primer
in an amount of about 0.5 percent by weight of the second part or
greater, more preferably about 1 percent by weight of the second
part or greater, and most preferably about 2 percent by weight of
the second part or greater. Preferably the plasticizer is present
in the second part of the multi-part primer in an amount of no more
than about 5 percent by weight of the second part or less, more
preferably no more than about 3 percent by weight of the second
part or less, and most preferably no more than about 2.5 percent by
weight of the second part or less.
[0099] Particulate Fillers
[0100] The multi-part primer may, in some exemplary embodiments,
include, or have added to it, at least one optional filler. The
filler may, in some embodiments, comprise a flame retardant or a
pigment. Mixtures of different fillers may also be used. Fillers in
particulate form are presently preferred. Filler particles
generally have an average particle size range between about 0.5 and
about 500 micrometers. In some embodiments, the filler particle is
between about 5 and about 20 micrometers.
[0101] Non-limiting examples of suitable fillers include: carbon
black, fly ash, slate dust, limestone, dolomite, siliceous fillers
(e.g. mica and other sheet silicates). metal carbonates (such as
calcium carbonate (e.g., chalk, calcite, marl, travertine, marble
and limestone), calcium magnesium carbonate, sodium carbonate,
magnesium carbonate), silica (e.g., quartz, glass beads, glass
bubbles and glass fibers) silicates (e.g., sodium silicate, calcium
silicate, calcium metasilicate, sodium aluminosilicate), metal
sulfates (such as calcium sulfate, barium sulfate, sodium sulfate,
aluminum sodium sulfate, aluminum sulfate), certain metal oxides
(e.g., calcium oxide (lime), alumina, tin oxide (stannic oxide),
titanium dioxide), metal sulfites (e.g., calcium sulfite), talc,
clays (e.g., montmorillonite, bentonite), feldspar, gypsum,
vermiculite, wood flour, Perlite.RTM., aluminum trihydrate, and the
like.
[0102] The filler may also be a metal filler. Examples of metal
fillers include copper, tin, zinc, bismuth, cobalt, antimony,
cadmium, iron, and titanium. Other miscellaneous fillers include
sulfur, organic sulfur compounds, graphite, boron nitride, and
metallic sulfides.
[0103] Flame retardant fillers, for example, sodium bicarbonate and
aluminum hydrate, could comprise all or a portion of the filler.
The multi-part primer may also be colored by adding colored
fillers, for example pigments, thereto. The multi-part primer may
also include an anticorrosion pigment. Exemplary suitable organic
coloring pigments include carbon black and phthalocyanine blue;
exemplary suitable inorganic coloring pigments include titanium
oxide, ferric oxide, lead chromate, and zinc oxide; exemplary
suitable anticorrosion pigments include lead oxide, calcium
plumbate, zinc chromate, basic lead chromate, zinc molybdate and
condensed zinc phosphate. The above mentioned examples of fillers
are meant to be a representative showing of some useful fillers,
and are not meant to encompass all useful fillers.
[0104] The fillers may be provided with a surface treatment.
Preferably, the surface treatment makes the surface of the filler
particles more oleophilic, more hydrophobic, or less hydrophilic.
Examples of suitable surface treatments include silanes, siloxanes,
and surfactants, particularly surfactants exhibiting a
hydrophile-lipophile balance (HLB) of ten or less.
[0105] The amount of filler is typically more than 5% by weight,
suitably less than 50% by weight, more preferably at least 10% to
at most 40% by weight, more preferably at least 20% to at most 30%
by weight, even more preferably about 25-28% by weight based on the
total weight of the first part of the multi-part primer.
[0106] Fibrous Materials
[0107] If desired, the multi-part primer may further comprise a
fibrous material (e.g. fibers such as, for example, glass fibers,
rock fibers, cellulose fibers, and/or polymeric fibers). In certain
presently preferred embodiments, the fibrous material comprises
polymeric fibers. The polymeric fibers preferably comprise a
polyolefin, for example, polyethylene, polypropylene, polybutylene,
combinations thereof, and the like. In general, the amount of
fibrous material added to the multi-part primer may vary, although,
in some exemplary embodiments, the concentration is preferably at
least 1% and no more than about 25% w/w, more preferably at least
2.5% and no more than 20% w/w, more preferably at least 5% and no
more than 15% w/w, and even more preferably from 5-10% w/w of the
multi-part primer.
[0108] Optional Reinforcing Layer
[0109] In additional exemplary embodiments, the roofing repair
system of any of the foregoing embodiments further comprises a
reinforcing layer. The reinforcing layer is preferably applied over
the at least partially cured activated multi-part primer, between
the at least partially cured activated multi-part primer and the
water-activated overcoat composition.
[0110] In some exemplary embodiments, the reinforcing layer
comprises a fiberglass mesh, a polyester mesh, a ethylene-propylene
dimer elastomer membrane, a chlorosulfonated elastomer membrane, a
poly(vinyl) chloride elastomer membrane, or a combination thereof.
Suitable fiberglass mesh reinforcing layers are sold under the
trade names SCOTCHKOTE.TM. Advanced CSM Reinforcing Mat,
SCOTCHKOTE.TM. Premier EC/UV Reinforcing Mat, and SCOTCHKOTE.TM.
Premier Plus Reinforcing Mat (available from 3M Company, St. Paul,
Minn.).
Optional Applicator
[0111] In certain exemplary embodiments, the roofing repair systems
according to any of the preceding embodiments further comprise an
applicator selected from a brush, a pad, a squeegee, a roller, a
sprayer, or a combination thereof. Suitable applicators are
described, for example, in U.S. Pat. No. 6,679,018 B2, which is
incorporated herein by reference in its entirety.
Method of Using the Roofing Repair System
[0112] In another aspect, the disclosure describes a method of
using the roofing repair system according to any one of the
preceding embodiments, the method comprising the steps of: (a)
mixing together the first part and the second part of the
multi-part primer to obtain an activated primer mixture, (b)
applying the activated primer mixture to a weathered surface of an
elastomeric roofing membrane, and (c) applying the water-activated
overcoat composition to the primer mixture on the weathered surface
of the elastomeric membrane.
[0113] In certain exemplary embodiments, step (b) is completed
within two hours after beginning step (a). In further exemplary
embodiments, step (c) is begun at least two hours after step (b) is
completed, and step (c) is completed no more than 168 hours after
beginning step (a).
[0114] The roofing repair system of the present disclosure is used
to overcoat a weathered surface of an elastomeric roofing membrane.
In some exemplary embodiments, the elastomeric roofing membrane
comprises ethylene-propylene dimer elastomer, chlorinated
polyethylene elastomer, chlorosulfonated polyethylene elastomer,
acrylonitrile rubber, poly(isobutylene) elastomer, thermoplastic
polyolefin elastomer, polyvinyl chloride elastomer, or a
combination thereof.
[0115] In some presently preferred embodiments, the surface to
which the activated multi-part primer is applied is prepared or
cleaned by washing with a detergent and lightly abrading the
surface prior to application of the activated multi-part primer.
Other surface preparation methods are described, for example, in
U.S. Pat. Nos. 3,707,521; 3,779,794; and 4,525,511; each of which
is incorporated herein by reference in its entirety.
[0116] In some exemplary embodiments of the foregoing method, the
activated multi-part primer mixture comprises water in an amount
sufficient to obtain a non-volatile solids content of from 30% to
50% by volume of the activated primer mixture.
[0117] The parts of the multi-part primer may be activated by
mixing the first part and the second part using mixing means
well-known in the art. Generally the components are blended in a
suitable mixer, for example, a propeller mixer inserted into a
tank, drum, or pail containing the components to be mixed. It may
be advantageous to add any plasticizers to the mixture so that such
mixture may be easily mixed and handled.
[0118] In use, the activated multi-part primer is generally applied
to the weathered surface of the elastomeric roofing membrane, and
allowed to dry or at least partially cure at ambient temperature
for at least one hour, more preferably at least two hours, even
more preferably at least eight hours, and still more preferably at
least 16-24 hours. Curing can be accelerated by by pre-heating the
activated multi-part or the components of the multi-part primer
prior to mixing and application to the weathered surface of the
elastomeric roofing membrane, and/or by applying heat to the
applied activated multi-part primer using external heating means
such as a heat gun, flame gun or torch, and/or exposure to solar
radiation, and the like.
[0119] An optional reinforcing layer is then, in some exemplary
embodiments, preferably applied over the at least partially cured
activated multi-part primer, between the at least partially cured
activated multi-part primer and the water-activated overcoat
composition.
[0120] The water-activated overcoat composition is then applied
over the at least partially cured activated multi-part primer in
the presence of atmospheric moisture. Exposure to atmospheric
moisture is generally sufficient to result in curing of the
water-activated overcoat composition. Curing can be accelerated by
the addition of additional water, by pre-heating the
water-activated overcoat composition prior to application, and/or
by applying heat to the applied water-activated overcoat
composition using external heating means such as a heat gun, flame
gun or torch, and/or exposure to solar radiation, and the like.
[0121] Preferably the multi-part primer is formulated to provide a
working time of at least one hour, more preferably at least two
hours, even more preferably at least five hours, eight hours, 12
hours, or even 24 hours after activation before fully curing. In
such embodiments, the activated multi-part primer preferably fully
cures in 48 hours or less, more preferably 24 hours or less, even
more preferably 12 hours or less, and most preferably in eight
hours or less.
[0122] Preferably the water-activated overcoat composition is
formulated to provide a working time of at least one hour, more
preferably at least two hours, even more preferably at least five
hours, eight hours, 12 hours, or even 24 hours after activation
before fully curing. In such embodiments, the activated
water-activated overcoat composition preferably fully cures in 48
hours or less, more preferably 24 hours or less, even more
preferably 12 hours or less, and most preferably in eight hours or
less.
[0123] In some exemplary embodiments, the roofing repair system and
method of the present disclosure provides a number of unexpected
results and advantages. In exemplary embodiments, the roofing
repair system and method uses a water-based multi-part primer that
has low toxicity, is environmentally benign, has excellent shelf
stability, is easy to apply, and, when activated, has a
sufficiently low viscosity to permit penetration and good adhesion
of the primer layer to a weathered surface of an elastomeric
roofing membrane.
[0124] In further exemplary embodiments, the roofing repair system
includes a water-activated overcoat composition that reacts with
(i.e. covalently bonds to) the at least partially cured activated
primer layer on the weathered surface of the elastomeric roofing
membrane, thereby promoting good interlayer adhesion between the
overcoat layer and the primer layer, as well as good adhesion of
the roofing repair system to the weathered surface of the
elastomeric roofing membrane. Moreover, the roofing repair system
may be formulated to contain little or no volatile organic
solvents, is typically easy to apply by relatively unskilled works
using a variety of application methods (e.g. brushing, rolling,
spraying, and the like), and generally exhibits excellent extended
shelf stability. The roofing repair system thus offers an effective
and relatively low cost solution to the problem of renewing,
refurbishing, or repairing weathered single ply roofing surfaces
which employ elastomeric roofing membranes, particularly EPDM or
HYPALON.RTM. elastomeric roofing membranes.
[0125] Exemplary embodiments of roofing repair systems and methods
are further illustrated by the following non-limiting example, but
the particular materials and amounts thereof recited in the
example, as well as other conditions and details, should not be
construed to unduly limit this disclosure.
EXAMPLE
[0126] An exemplary embodiment of the disclosure will now be
described. Embodiments of the present disclosure may take on
various modifications and alterations without departing from the
spirit and scope of the disclosure. Accordingly, it is to be
understood that the embodiments of the present disclosure are not
to be limited to the following described exemplary embodiment, but
is to be controlled by the limitations set forth in the claims and
any equivalents thereof. Unless otherwise expressly noted, all
parts, percentages, ratios, etc. in the Example and the rest of the
specification are by weight. In addition, the following
abbreviations and materials are used in the Example below:
Materials:
Hydroxyl-Functional (Meth)acrylic Polymer
[0127] BAYHYDROL A 145 is a dispersion of a hydroxyl-functional
acrylic polymer (43-47% w/w) in water (available from Bayer
Material Science LLC, Pittsburgh, Pa.).
Hydrophilic Polyfunctional Aliphatic Isocyanate
[0128] BAYHYDUR.RTM. XP 2487/1 is a hydrophilic, water dispersible
poly-functional aliphatic polyisocyanate based on hexamethylene
diisocyanate (available from Bayer Material Science LLC,
Pittsburgh, Pa.).
Hydrophobic Polyfunctional Aliphatic Isocyanate
[0129] DESMODUR N 3600 is a hydrophobic, solvent-free
Optional Catalyst
[0130] Dibutyl tin dilaurate (available from Sigma-Aldrich Chemical
Co., St. Louis, Mo.).
Optional Biocides
[0131] PROMEX.TM. Na2OS, a glycolic solution (20% w/w) of
1,2-Benzisothiazolin-3-one (available from Prom Chem, Ltd.,
Caterham, United Kingdom).
[0132] ACTICIDE.RTM. MKW1, a water-based solution (32-38% w/w) of
3-(3,4-dichlorophenyl)-1,1-dimethylurea;
3-iodopropargyl-N-butylcarbamate; and protected
2-n-octyl-4-isothiazolin-3-one (available from Thor Specialties,
Ltd., Northwich, Cheshire, England).
Optional Surfactant
[0133] Surfynol.RTM. 104E, a solution (50% w/w) of
2,4,7,9-tetramethyl-5-decyne-4,7-diol in 2-ethylhexanol (available
from Air Products and Chemicals, Inc., Allentown, Pa.).
Optional Dispersant
[0134] DISPERBYK 190, a 40% w/w aqueous solution of a high
molecular weight block copolymer with pigment affinic groups
(available from BYK-Chemie GmbH, Wesel, Germany).
[0135] AMP-95, a solution (95% w/w) of 2-amino-2-methyl-1-propanol
in water (available from Angus Chemie GmbH, Ibbenbiiren,
Germany).
Optional Particulate Filler
[0136] Tiona.RTM. 595, an alumina/zirconia/organic surface treated
titanium dioxide (available from Millenium Chemicals, Hunt Valley,
Md.).
[0137] MICRO-TALC AT 1, talc powder available from
Suter-Kunststoffe AG, Jegenstorf, Switzerland).
Optional Rheology Modifer
[0138] ACRYSOL.TM. RM-825, a non-ionic polyurethane rheology
modifier (25% w/w) in water/butyl carbitol (75/25% w/w) (available
from Rohm and Haas Co., Philadelphia, Pa.).
[0139] Laponite RDS, an aqueous dispersion (10% w/w) of synthetic
layered silicate incorporating an inorganic polyphosphate peptiser
(available from Rockwood Additives, Ltd., Cheshire, United
Kingdom).
Optional Solvent
[0140] Proglyde DMM, a mixture of isomeric dipropylene glycol
dimethyl ethers (available from Dow Chemical Co., Midland,
Mich.).
Water-Activated Overcoat Composition
[0141] 3M SCOTCHKOTE.TM. Polyurethane Base Coat EC/UV, a
water-activated overcoat composition comprising at least one
compound selected from polyketimines having amino groups attached
to secondary carbon atoms, polyenamines, and oxazolidines
(available from 3M Co., St. Paul, Minn.).
Substrates
[0142] Ethylene-propylene diene monomer (EPDM) elastomeric roofing
membrane (obtained from Goodyear Rubber Co., Akron, Ohio), was
weathered by exposure to solar radiation and the elements.
[0143] Chlorosulfonated ethylene (HYPALON.RTM., obtained from E.I.
DuPont de Nemours Corp., Wilmington, Del.), was weathered by
exposure to solar radiation and the elements.
[0144] All substrates were washed with a detergent and lightly
abraded with a 3M abrasive pad (available from 3M Company, St.
Paul, Minn.) prior to application of any primer or roofing repair
system.
Preparative Example 1
Multi-Part Primer
[0145] This example illustrates the preparation of a multi-part
primer comprising a first part including a hydroxyl-functional
(meth)acrylic (co)polymer, and a second part including a mixture of
a hydrophilic polyfunctional aliphatic polyisocyanate and a
hydrophobic polyfunctional aliphatic polyisocyanate, wherein a
molar ratio of hydroxyl functionality in the first part to
isocyanate functionality in the second part is less than 1.
First Part (Including a Hydroxyl-Functional (Meth)Acrylic
(Co)Polymer)
[0146] The following ingredients were combined in the order given
at the indicated weight percentages and mixed by stirring for 30
minutes to obtain a fluid mixture:
TABLE-US-00001 Water: 15.60% Laponite RDS: 6.10% AMP-95: 0.04%
Surfynol .RTM. 104E: 0.76% Tiona .RTM. 595: 3.82% DISPERBYK 190
1.95% MICRO-TALC AT 1: 22.89% BAYHYDROL A 145: 48.15% PROMEX .TM.
Na2OS: 0.08% ACTICIDE .RTM. MKW1: 0.23% ACRYSOL .TM. RM-825:
0.38%
[0147] The specific gravity of the mixture was measured as
1.26.
Second Part (Including a Mixture of a Hydrophilic Polyfunctional
Aliphatic Polyisocyanate and a Hydrophobic Polyfunctional Aliphatic
Polyisocyanate)
[0148] The following ingredients were combined in the order given
at the indicated weight percentages and mixed by stirring for 30
minutes to obtain a fluid mixture:
TABLE-US-00002 BAYHYDUR .RTM. XP 2487/1: 40.00% DESMODUR N 3600:
40.00% Proglyde DMM: 20.00%
[0149] The specific gravity of the mixture was measured as
1.10.
Example 1
Roofing Repair System
[0150] This example illustrates the preparation of a roofing repair
system comprising the multi-part primer of Preparative Example 1
and a water-activated overcoat composition comprising at least one
compound selected from polyketimines having amino groups attached
to secondary carbon atoms, polyenamines, and oxazolidines. The
First Part of the primer of Preparative Example 1 was combined with
the Second Part of the primer of Preparative Example 1 at a 6:1
ratio (volume/volume) based on the measured specific gravities of
the First Part and the Second Part. The mixture was mixed for 15
minutes to activate the primer.
[0151] The resulting activated primer was applied to a weathered
EPDM substrate as described above. After allowing the activated
primer coating on the weathered EPDM substrate to dry for
approximately eight hours, the primer layer was overlaid with a
strip of woven polyester mesh fabric (to facilitate manual pull
adhesion testing) and then coated with a layer of water-activated
overcoat composition, 3M SCOTCHKOTE.TM. Polyurethane Base Coat
EC/UV. The sample was allowed to dry before testing according to
the following test methods.
Test Methods:
[0152] The sample of Example 1 was first assessed for dry adhesion
of the roofing repair system to the prepared EPDM substrate, after
which adhesion was measured after exposing the coated substrate to
100% humidity. Adhesion was tested by making a cut across the
surface of the coating with a sharp blade, and pulling on the
exposed embedded polyester mesh fabric by hand to determine whether
the mesh fabric could be removed from the weathered EPDM
substrate.
[0153] Adhesion was retested after applying the following
environmental exposure conditions on the coated weathered EPDM
substrate: [0154] 1. Cold water immersion for 10 weeks; [0155] 2.
Exposure to ultraviolet (UV) light 1000 hours (according to ASTM
Test Method G53, using a QUV tester equipped with B-313 tubes,
programmed for four hours of UV exposure @ 60.degree. C.
alternating with 4 hours of exposure to a high humidity condensing
environment @ 40.degree. C.); and [0156] 3. Humidity Cabinet
Exposure for 800 hours (according to ASTM Test Method BS3900; Part
F2)
[0157] Adhesion after all three environmental exposure conditions
was visually observed to be excellent, with no visible failures of
the bond at the interface with the weathered EPDM surface, or at
the interface between the activated primer layer and the
water-activated overcoat composition. The mode of failure was
observed to be entirely cohesive within the weathered EPDM
elastomeric roofing membrane.
[0158] The formulations of Preparative Example 1 (multi-part
primer) and Example 1 (roofing repair system) were also applied to
a weathered HYPALON.RTM. the procedures and methods of Preparatory
Example 1 and Working Example 1, except that weathered HYPALON.RTM.
was used as the substrate instead of weathered EPDM. Adhesion after
all three environmental exposure conditions was visually observed
to be excellent, with no visible failures of the bond at the
interface with the weathered HYPALON.RTM. surface, or at the
interface between the activated primer layer and the
water-activated overcoat composition. The mode of failure was
observed to be entirely cohesive within the weathered HYPALON.RTM.
elastomeric roofing membrane.
[0159] Reference throughout this specification to "one embodiment,"
"certain embodiments," "one or more embodiments" or "an
embodiment," whether or not including the term "exemplary"
preceding the term "embodiment," means that a particular feature,
structure, material, or characteristic described in connection with
the embodiment is included in at least one embodiment of the
exemplary embodiments of the present disclosure. Thus, the
appearances of the phrases such as "in one or more embodiments,"
"in certain embodiments," "in one embodiment" or "in an embodiment"
in various places throughout this specification are not necessarily
referring to the same embodiment of the exemplary embodiments of
the present disclosure. Furthermore, the particular features,
structures, materials, or characteristics may be combined in any
suitable manner in one or more embodiments.
[0160] While the specification has described in detail certain
exemplary embodiments, it will be appreciated that those skilled in
the art, upon attaining an understanding of the foregoing, may
readily conceive of alterations to, variations of, and equivalents
to these embodiments. Accordingly, it should be understood that
this disclosure is not to be unduly limited to the illustrative
embodiments set forth hereinabove. In particular, as used herein,
the recitation of numerical ranges by endpoints is intended to
include all numbers subsumed within that range (e.g. 1 to 5
includes 1, 1.5, 2, 2.75, 3, 3.80, 4, and 5). In addition, all
numbers used herein are assumed to be modified by the term `about`.
Furthermore, all publications, published patent applications and
issued patents referenced herein are incorporated by reference in
their entirety to the same extent as if each individual publication
or patent was specifically and individually indicated to be
incorporated by reference. Various exemplary embodiments have been
described. These and other embodiments are within the scope of the
following claims.
* * * * *