Note : Les descriptions sont présentées dans la langue officielle dans laquelle elles ont été soumises.
9474
This invention relates to the construction of buildings
and is specially concerned with building elements subjected to
weather, for example, roofs and walls, and with components of
these elements, for instance, coatings.
This application is a division of Application Serial
No. 278,053, filed May 10, 1977, which claims primarily a
structure,for example, a roof having an insulating blanket
carrying a protective sheath made up of a load-supporting shell
of reinforced concrete covered by a weather-resistant rubbery-
textured microporous membrane, and a method of making such astructure. The present application is directed to a preferred
insulating blanket and to special shingles of which this blanket
is constructed.
A specific utility of the invention is in providing
an improved form of Bermuda roof. This type of roof will,
therefore, serve as a convenient starting point for the under-
standing of the invention, although it must be understood that
the invention is not limited to this use. The Bermuda roof has
a sloping deck clad with a plurality of limestone slabs over-
lapped to provide a stepped or contoured surface which iscovered with paint or a cement wash to render it waterproof.
This roof has a characteristic appearance as will be readily
recognized by anybody who has visited Bermuda.
Applying the invention to the construction of a
Bermuda roof, the stone slabs are replaced by wedge-shaped
interfitting insulating shingles of substantially impervious
synthetic resin closed cell foam firmly secured to the deck,
to form a continuous insulating blanket. The blanket is
covered by a load-bearing impact-resistant weather impervious
sheath. The sheath is made up of a hard, essentially reinforced
concrete shell adhering tenaciously to the top surface of the
shingles and an essentially rubbery-textured membrane covering
. ' 1 ~ ~
1~39947~
the shell and adhering tenaciously to it. Critical characteris-
tics of the sheath materials and advantageous detailed features
of construction which may be accornplished by their use will be
described as this disclosure progresses.
The general prior art of constructing roofs and walls
is replete in the use of synthetic resin foam in cornbination
with other structural and coating material. For example, one
patent, which, at first glance, might be considered analogous
to the applicant's development, is directed to cladding a flat
surfaced wall or roof, employing a plurality of resilient --
thermo-insulating cellular polystyrene plates to form an insu-
lating layer covering the wall or roof support. Over the insu-
lating layer there is applied a continuous intermediate layer
consisting essentially of a synthetic resin having a reinforcing
glass fabric embedded in it. The patentee describes the inter-
mediate layer as being of polyvinyl chloride or a butadiene
styrene copolymer, having quartz powder distributed throughout
and a propionic acid binder which he says may be mixed with an
equal amount of Portland cement. On the free outer face is
formed a continuous plaster coating, consisting essentially of
a mixture of quartz and synthetic resin cementitious material,
which the patentee suggests may be formed of propionic acid
~ ester.
This prior art has the following characteristics.
Polyvinyl chloride deteriorates on ultraviolet exposure and
gives off corrosive hydrogen chloride. Polyvinyl chloride
; film blackens and brittles and requires plasticizers for usable
flexibility. Butadiene styrene polymers oxidize in ultraviolet
light with severe yellowing and embrittlement due to cross-
linking. They require the use of antioxidants. Propionic acid
esters and polyvinyl acetates hydrolize in the presence of
moisture and alkali.
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.,
10~947'~
The construction described in Application 278,053
contrasts with the teachings of this and other prior art patents
by its special protective load-bearing and weatherproof sheath
in which there are married together a hard essentially rein-
forced concrete shell covering the insulating blanket and a soft
essentially rubbery-textured plastic membrane covering the shell,
the nature and advantages of which will be apparent from the
detailed description to follow. A feature of the sheath is that
the components may be applied at once at essentially their ulti-
mate thickness. Both the cement mixture to form the concreteshell and the extended resinous mixture for forming the membrane
are materials in a flowable plastic state which can be spread
on a flat or uneven surface. The materials and construction
specified by the patentee endow the structure with important
properties lacking in materials suggested in earlier proposals.
In a preferred construction the sheath is in the form
of a protective bonnet which covers the entire insulating blan-
ket and extends in a girdle over the edges of the roof, with a
shell terminating at the bottom of the downwardly extending `
surfaces and the membrane extending over the shell and under-
neath the edges to further anchor the bonnet to the roof. This
construction is desirably provided by a finishing strip which -`
- extends about th0 edge of the deck at the edges of the roof and
which has a downwardly extending face meeting an underface. In
this construction the insulating blanket desirably covers the
deck and finishing strip and has a downwardly extending face
forming a continuation of the downwardly extending face of the
finishing strip. The shell extends along the downwardly extend-
ing face of the finishing strip and terminates thereon and the
membrane extends beyond the shell and along the undersurface of
the finishing strip. The downwardly and inwardly extending
parts of the bonnet constitute the girdle which supplement the
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1099474
tenacious surface adherence of the roof covering to the deck in
anchoring it to the superstructure of the building.
The blanket is preferably made up of a number of
shingles specially constructed according to the invention.
Each shingle has an elongated body of plastic foam tapering
from a major thickness adjacent a leading face to a minor
thickness adjacent a trailing face. The body has one end pro-
vided with a flange protruding therefrom and the other with a
recess to interfit with the flange and recess of adjacent
shingles. The leading face has a recess to interfit with the
trailing margin of the adjacent trailing shingle. In the
insulating blanket the shingles are aligned in rows desirably
with the shingles of respective rows staggered.
A preferred sheath is made up as follows. It includes
a continuous hard tough shell from about 1.5 mm. to about 6.5 mm.
thick of reinforced concrete made with hydraulic cement modified
with from about 5% to 20% on a solids weight basis of the total
of a synthetic resin latex modifier and desirably reinforced
with glass fibers. This shell adheres tenaciously to the sur-
face of the insulating blanket. Adhering tenaciously to theshell is a soft rubbery membrane made by laying down composi-
tions according to the present invention. They are based on a
~ binder matrix, according to the present invention, of a non-
plasticized latex of an acrylic elastomeric-type polymer having
a Tg within the range from about -35C. to about -45C. con-
taining from about 50% to about 60% by weight of finely divided
extender.
The membrane and shell are married together as an
essentially integral unit with the shell providing load-bearing
strength and the membrane sealing the shell from the outside
and preserving properties of the relatively thin concrete which
could be otherwise deteriorated by exposure to the elements.
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~t399474
Because of interaction between the setting membrane material and
the concrete, the interface between the membrane and the shell
is free of moisture-escape blisters which often occur between
latex-deposited films and substrates. This is because the
membrane is formed with an emulsion (or latex) in which the
discrete copolymer (acrylic) particles are dispersed and which
permits the formation of a film with minute capillary openings
which permit moisture vapor trapped in a building to escape
without causing blistering of the membrane as would occur with
a membrane formed with a solution polymer binder (continuous
solid film as taught in the prior art patent mentioned).
Having thus generally described the invention, it will
be referred to in more detail by reference to the attached draw-
ings by illustrating preferred embodiments and in which: ~ -
Figure 1 is a fragmentary perspective view of a
- building having a roof constructed, accord- :
ing to the invention, with parts removed to
: show the construction;
Figure 2 is a top plan view of a preferred form of
insulating shingle used to form the insulat-
ing blanket;
, Figure 3 is an enlarged fragmentary perspective
view of one end of the shingle shown in
Figure 2;
Figure 4 is a fragmentary perspective view of the
other end of the shingle shown in Figure 2;
Figure 5 is a cross-section along the line 5-5 of
Figure 2;
Figure 6 is an enlarged fragmentary cross-section
. 30 along the line 6-6 of Figure 1 through the
eaves part of the roof,
,, .
.
,........................................................................... .
~099479t
Figure 7 is an enlarged fragmentary cross-section
along the line 7-7 of Figure 1 through the
verge of the roof, and
Eigure 8 is an enlarged fragmentary cross-section
illustrating the application of the inven-
tion to another type of roof.
Referring more particularly to the drawings, there is
shown a building having a wall A made up of a number of building
blocks 15. A roof B is carried by the wall A through an end
beam 16, side beams 17 and 18 enclosing a concrete belt course
19 having a reinforcing rod 20, and a ridge beam 21. Rafters
22 extend between the ridge beam and the beam 18 and a rafter
foot 23 protrudes from each rafter 22 through the belt course
19 and through a notch in the beam 17.
A roof deck C is made up of sheets 25 of plywood
butted together edgewise, with fissures 26 intervening them.
The undersurface of the plywood 25 is preferably covered with
a layer of plaster 25a prior to erection. A preferred material
for this purpose is sold as "Sunny Plaster SP" by Coatings
International Limited, Hamilton, Bermuda. Preferably the
fissures 26 are caulked with a caulking composition. The roof
deck C slopes at an angle to provide drainage and an aesthetic
~ appearance in the roof above it.
On top of the deck C is a substrate in the form of an
insulating blanket D made up of a number of interfitting syn-
thetic resin foam shingles 30. The shingles are preferably
held to the deck by adhesive 31 although they may be secured by
nailing or otherwise. A preferred adhesive is a water-based
foam and tile adhesive sold under the trade mark "~ova 96" by
Coatings International Limited of Hamilton, Bennuda.
In the example roof, the shingles 30 are of the form
shown in Figures 3 to 5. Each shingle is tapered and has an
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~99~9L
undersurface 32 and a merging upper surface 33. Each shingle
has a stepped leading end with off-set surfaces 34 and 35 with
an intervening shoulder 36 providing a receiving recess (for
the thin end of the adjacent shingle higher on the roof) and a
thin end 37. One side of each shingle is stepped to provide a
side surface 38 and a projecting flange 39. The other side is
stepped to provide a side surface 40 and an inwardly stepped
narrow surface 41 and shoulder 42 providing a recess for
receiving the flange 39 of the adjacent shingle. The shingles
are laid in interlocking relationship with those in one row
staggered relative to those in the next, as will be readily
apparent from Figure 1 considered in conjunction with the con-
struction of the shingles in Figures 2 to 5. Together the
shingles form a continuous (apart from the fissures between
the shingles) blanket having a stepped or contoured surface
covering the deck C. The use of relatively short shingles
instead of an elongated strip minimizes the overall expansion
`~ and contraction across the roof with temperature changes.
The synthetic insulating foam material of the
shingles, because of its voids provide good insulation of the
deck C against heat and cold. However, the material lacks
structural strength and impermeability to moisture and other
influences and requires protection in these respects. To this
end, the entire surface of the insulating blanket D is pro-
tected, according to the invention, by the adhesive load-
carrying sheath made up of a hard, essentially reinforced
concrete shell E covered by the soft essentially rubbery-tex-
tured plastic membrane F, applied as follows.
The hard shell E is preferably formed by spreading
over the continuous surface of the roof B a coating of spread-
able hydraulic cement-aggregate mix reinforced with finely
divided inert material and short glass fibers. The coating is
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1~399474
allowed to set to form the thin continuous hard concrete layer
E having a thickness from about 1.5 mm. to about 5 mm. conform-
ing to the surface of the insulating layer D and adhering
tenaciously to it.
The soft rubbery membrane F is formed by spreading,
over the concrete shell E, a matrix-forming composition con-
taining major amounts of finely divided extender and a synthe-
tic resin aqueous emulsion binder. The coating solidifies to
form the rubbery membrane, adhering strongly to the shell. It
conforms to the surface contours of the insulating layer D and
accommodates its expansion and contraction while adhering
tenaciously to its surface.
As shown in Figure 6, the leading edges of the
shingles at the lower edge~or eaves of the roof extend beyond
the edge of the deck 25 and are supported by an overall rec-
tangular eaves-,finishing strip 42. The strip 42 has an upper
face 43 juxtaposed to the undersurface 32 of the shingles 30,
a recess 44 receiving the edge of the deck plywood sheets 25,
an outer face 45, and an undersurface 46 which is provided with
a longitudinal groove 47 to intercept water blown inward along
its surface. The surfaces 36 and 35 of the shingles form with
the surface 45 of the strip a pocket to receive a concrete
fillet. In accordance with the invention, the shell E con-
tinues from the upper surface 33 of the eaves shingles down
their leading face 34 and into the pocket to provide a massive
anchoring fillet P which adheres tenaciously to the under-
surfaces of the shingles 34 and to the surface 45 of the strip
42.
The membrane F also continues over the edge of the
roof, covering the parts of the shell in that zone. The mem-
brane extends beyond the shell along the undersurface 46 and
into the surface of the groove 47, adhering tenaciously to
-- 8 --
1~994'~4
these surfaces. The shell E is thus anchored to the edge of the
roof and acts to protect and retain the edges of the eaves
shingles 30. The membrane F completes the job by enveloping the
entire edge of the roof in what amounts to a bonnet having a
girdle extending down from the top surface and then inwards,
sealing the roof against ingress of moisture and further anchor-
ing to the roof deck the shingles of the insulating blanket D
and the entire sheath made up of the shell E and the member F.
At the end of the roof there is a verge-finishing
strip 50 like the eaves-finishing strip 42. This is overlapped
by the shingles 30, the undersurfaces of which are adhesively
secured to the strip by adhesive 31.
The skirt of the shell E extends down the verge to the
bottom of the side of strip 50. The membrane F extends over the
verge covering the shell E and across the undersurface of the
strip 50 as far as its groove 51.
Figure 8 shows the corner of another building employ-
ing certain teachings of the invention. The top of a concrete
wall 55 supports a steel deck 56 which, in turn, supports a
concrete slab 57. Anchored by bolts 58 to the concrete slab is
a plywood strip 59. In accordance with the invention this
corner structure is covered with a thick fillet 60 of a glass
fiber-filled coating composition of the type used to form the
membrane F. A continuous membrane 61 is also applied to adhere
tenaciously to the surface of the slab 57, the fillet 60, and
the strip 59 to extend underneath the plywood strip in a
flange 62.
Variations in Materials
While the preferred material for the supporting deck
A of the structure shown in Figures 1 to 8 has b~en shown as
sheets 25 of plywood, other structural materials can be employed,
for example, tongue-and-groove timber, corrugated iron, or
1~999 74
concrete.
The insulating blanket D is preferably of a synthetic
resin foam material capable of being worked, for example, by
sawing from a block or sheet or by molding, to provide shingles
30 as described which can be fitted together to provide a con-
tinuous covering apart from the fissures at the interface
between the respective shingles 30. A preferred material is a
closed cell polystyrene foam of a density from about 1 to about
3 pounds, preferably approximately 2 pounds, per cubic foot.
One good material is sold under the trade mark "Styrofoam" as
described, for example, in the booklet "AMSPEC Full Sidewall
Insulation and Wood Frame Construction with Styrofoam Brand
Plastic Foam", Amspec Inc., September 1972, Columbus, Ohio.
Shell
The shell E is essentially a continuous hard tough
load-carrying sheet of reinforced concrete having a thickness
within the range from about 1.5 mm. to about 5 mm. which armor-
plates the blanket D and adheres tenaciously to it. Preferably
this concrete is made with hydraulic cement, fine aggregate and
reinforcing material, preferably glass fiber, modified by the
use of from about 5% to about 20% of a synthetic resin latex
cement modifier to provide it with high impact strength (at
least 6 to 16 inch pounds), high flexural strength, thin section
strength, high tensile strength (greater than 100 pounds per
s~uare inch), shear bond adhesion (at least ten times that of
unmodified concrete made with Portland cement), and the capacity
of adhering tenaciously to the substrate and other properties.
In certain cases, for example, where the substrate is flat,
scrim cloth may be used to reinforce the concrete. The result-
ing concrete also has a high tensile and flexural strength andadhesion necessary to resist freeze-thaw lifting and the dur-
ability to withstand weathering and ultraviolet degradation.
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~99474
The cement mix is curable under ambient conditions.
Preferred cement modifiers are aqueous acrylic emul-
sions as for example described in the article entitled "Acrylic
Modifiers for Cement","Resin Review", Vol. 24, No. 2 (1974).
A preferred cement composition, according to the invention,
contains from about 45% to about 60% Portland cement by weight
on a dry solids basis and about 5% to about 20% of the acrylic
cement mortar modifier resin emulsion "Rhoplex E-330" (solids
47% + 0.05%) described in the brochure "Rhoplex E-330 Cement
Mortar Modifier", Rohm and Haas, August 1974, or "Rhoplex MC-76"
(solids 47% + 0.5%). Less preferred concretes may be obtained
by using other commercial latex cement modifiers, for example,
containing butadiene styrene, vinylidene chloride, or polyvinyl
acetate. ~ -
Preferred aggregate materials are fine silica sand
within the size range from about 20 to about 100 microns, finely
divided calcium carbonate of a size range from about 2 to about
20 microns, and quartz flour of a size range from about 10 to
100 microns. The quartz flour provides for a hard finish. The
calcium carbonate gives spreading and working characteristics.
A preferred concrete is made by mixing together a
first product including Portland cement, short glass fibers,
~ silica sand, powdered limestone, wetting agents and defoamers
with a second product including a liquid acrylic aggregate
additive containing enough water for a concrete mix.
The cement mixture can be sprayed on or spread on with
a trowel. If sprayed on it is subsequently troweled or brushed.
The drying time for the concrete is two to three hours and the
setting time about 12 hours. The modified concrete reaches
about 90% of its ultimate strength in about 48 hours and cures
after about seven days.
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1~3994~
The Membrane
The membrane F, to the manufacture of which the pre-
sent invention is directed, is essentially a matrix of a rubbery
material laid down from a creamy spreadable latex, according to
the invention, of elastomeric-type synthetic resin highly filled
with a finely divided inert extender as a bodying agent. The
membrane is a continuous layer tenaciously adhering to its
substrate and having a thickness within the range from about
0.75 mm. to about 3.0 mm. The extender should be present in an
amount from about 50% to about 60% by weight of the total matrix
plus filler. A preferred extender is preferably calcium car- -
bonate, desirably being a blend of different sizes having a
particle size within the range from about 2 to about 12 microns
with the average from about 4 to about 12 microns. The mixed
particle sizes improve packing of the system to the benefit of
membrane continuity and physical properties. The membrane is
resistant to fumes, chemicals, sea air, salt spray, it is freeze- ;`
resistant, non-brittle at low temperatures, non-runny at high
temperatures, stable under prolonged exposure to ultraviolet
light, has low dirt pick-up and is tenaciously adhesive to its
substrate.
A preferred coating composition for the membrane is
made, according to the present invention, by using as a binder
composition an intimate mixture of "Rhoplex LC-67" (Tg about
-40C. to -45C., pH between about 7 and 8) acrylic emulsion
for plasticizer-free caulks and "Rhoplex AC-707" (Tg about +5C.
to about +15C.) high solids acrylic emulsion vehicle in the
proportions to provide a film having a Tg within the range from
about -35C. to about -45C. For some applications the AC-707
may be omitted allowing for high loading with extender or allow-
ing at the same extender level for a lower Tg down to about
-45C. For the significance of Tg see the brochure "The
-- 12 --
1~35'9~74
Characterization of Polymers" by Rohm and Haas (CM-106 D/cd)
and "Plastics in the Modern World" by Couzens and Yarsley,
Penguin Books Ltd. (1968), pages 217 and 218.
Preferred formulations are as follows, the percentages
being given by weight:
Total resin emulsion solids 44%
Total filler and pigment 51%
Miscellaneous constituents 5%
The composition, as manufactured, should have a con-
sistency within the range from about 5 to about 50 seconds as
measured by the Semco running test referred to as follows in
"Formulating Guide for Acrylic Latex Caulks" by Rohm and Haas,
Philadelphia, 1975. A 6 oz. sample of the composition is
loaded into a polyethylene cartridge and gunned under a pressure
of 50 pounds per square inch through a Semco air-powered caulk-
ing gun fitted with a Semco nozzle with a 1/8th lnch diameter
orifice. The time, in seconds, required to gun the caulk sample
is the figure used to define the consistency. For example, if
it takes 25 seconds to gun the sample, the composition is said
to have a consistency of 25. The consistency may be adjusted
with water or a glycol for spray or brush application and open
time.
~ The membrane material can be brushed on, troweled on,
or sprayed on and brushed. A second and third coat, depending
on thickness, can be applied in a minimum of about two hours
and a maximum of about 12 hours depending on weather conditions.
The membrane should not be applied till 4 or 5 hours at the
earliest, preferably about 12 hours after the concrete is
applied.
In more detail "Rhoplex LC-67" is described in the
brochure of Rohm and Haas entitled "Rhoplex LC-67 Acrylic
Emulsion for Plasticizer-Free Latex Caulks" (1976). As des-
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~C~9947~
cribed in this literature, this binder has the following charac-
teristics, in terms of its use in caulks. By its use, as a
binder, a high quality caulk may be made which is not subject
to plasticizer migration problems such as glossing and tackify-
ing of paints with accompanying dirt pick-up, mildew growth,
and loss of caulk flexibility on exterior exposure. Caulks
using this binder retain the performance advantage of current
commercial caulk emulsions over conventional latex caulks in
terms of low shrinkage, initial low temperature flexibility,
resistance to discoloration on aging or ultraviolet exposure,
and dry and wet adhesion to alkyd paints, glass, glazed ceramic
and concrete substrates. Using formulations embodying this
binder, a latex caulk can be manufactured which exhibits
superior adhesion properties and superior elongation with
satisfactory tensile and recovery properties.
According to the manufacturer's literature, this
aqueous acrylic emulsion polymer binder has the following
typical properties:
Appearance Milky white liquid
Solids content, % 64.5 to 65.5
pH, as packed 4.8 to 5.4
Specific gravity 1.04
Density, lbs./U.S. gal. 8.66
Minimum film-formation
temperature, C. less than 0
Glass transition temperature
(Tg), C. approximately -50
Tukon hardness (KHN) less than 1
Storage stability protect from freezing
To further characterize this binder, it should be
noted that typical caulk formulations using it contain along
with it major amounts of a primary extender or filler to provide
good caulk performance in terms of caulk rheological and
- 14 -
11~395~47'4
application properties and in minor amounts of a drying retarder
to provide working times for applying the caulk, defoamer to
eliminate gas, a wetting agent and emulsifier which tends to
stabilize the binder emulsion and improve the caulk mechanical
stability and lowers the caulk consistency and enhances its
package or self-stability, a primary pigment dispersion which
contributes to forming a stable homogeneous and creamy low
consistency caulk, a secondary pigment dispersion which is
essential to form a stable, homogeneous caulk with good pack-
age stability, and an organic liquid which provides freeze-thaw
stability.
Caulk formulations of the type described to charac-
terize the binder are described to explain the nature of the
formulation to which the compositions of the present invention
belong. The caulk formulations do not, themselves, normally
have the consistency required for application by normal coating
methods and where laid down in a coating layer do not have
adequate coating characteristics.
"Rhoplex AC-707" is described in the Rohm and Haas
booklet "Rhoplex AC-707 High Solids Acrylic Emulsion Vehicles
for Exterior and Interior Latex Paints" (July 1974).
This literature describes the binder as a high solids
~ acrylic emulsion polymer having the following typical properties:
Solids content, % 65.0 -+ 0.5
pH 9.0 to 9.7
Viscosity, cps.
Brookfield ~o. 3 spindle - 60 RPM 300 to 700
Minimum film formation
temperature, C. + 10C. to + 12C.
Tukon hardness, KHN <1
Weight per gallon, lb. 8.97
Bulking value, gal./lb. - wet 0.1115
- dry 0.107
- 15 -
1~9~474
Mechanical stability
Waring Blender - 5 cycles OK
Freeze-thaw stability - 5 cycles OK
Calcium ion stability OK
Oven stability - 10 days at 140F. OK
Tgl approximately + 10C.
Other qualities of the binder are that the stability
of the emulsion formed with it is excellent and problems are
not experienced with sedimentation or excessive skinning as
might be expected from its high solids content. Usual precau-
tions should be taken against the loss of water from the surface
of the emulsion, when handled in bulk storage tanks and drums.
A humidification system is recommended with bulk storage and
lids should be replaced promptly on drums after use.
A preferred coating composition, according to the
invention, includes, besides the two emulsion binders, and the
extender pigment, auxiliary functional constituents as follows:
"Varsol 1" (trade mark) a solvent type material which acts to
retard skin formation and allow adequate time for working the
coating; "Nopco NXZ" (trade mark) as a defoaming agent in an
amount within the range from about 0.1% to 0.3%; "Triton X-405"
(trade mark) a nonionic surfactant present in an amount from
about 0.5% to about 0.8%; "Calgon T" (trade mark) a primary
pigment dispersant present in an amount from about 0.5% to
about 0.8%; "Oratan 850" (trade mark) a secondary pigment dis-
persant in an amount from 0.05% to about 0.15%; ethylene glycol,
an anti-freeze and pigment resin extender in an amount from
about 0.1% to about 0.3%; formaldehyde, as a package preserva-
tive in an amount from about 0.05% to about 0.15%; ammonia in
an amount effective to adjust the pH to within the range from
about 9 to about 11; rutile titanium dioxide or other pigments
or equally finely ground material or materials in an amount
within the range from 0.7% to about 2.0%. All these amounts are
- 16 -
1~99474
.
by weight on the total composition.
A caulk formulation, using the caulk forming binder
alone, employs "Methocel 60HG" (trade mark) as a thickener
which aids in attaining caulk slump resistance. For the pur- A
poses of the coatings of the invention such an agent is
omitted. Likewise, a caulk formulation, using the caulk form-
ing binder, employs "Silane Z-6040" (trade mark) to improve
adhesion to certain substrates, in particular wet adhesion to
glass and glazed ceramic tiles. Such material is omitted from
the present compositions unless they are to be applied to glass
or smooth ceramic substrates.
The mixing of the various materials to form the coat-
ing composition is relatively straightforward. Preferred
apparatus for mixing or similar high shear, low mixing equip-
ment is a Sigma Blade mixer. While the sequence of addition
of the constituents is not critical, a preferred sequence is
to mix the first and second binders together first. Half the
defoamer may also be added at that time. Then, the extender
is added slowly over a period of, typically, say a minute, and
then there is added slowly the "Varsol", the surfactants and
the dispersants. The mixture of the resin with the extenders
is quite stiff and lumpy and the addition of the surfactants
and dispersants makes it into a nice creamy mass. The total
mixing time may run, typically, to about an hour and a half
to form a smooth thick spreadable composition.
The inclusion of a fungicide, for example, formalde-
hyde, in addition to the adjustment of the pH well up into the
alkaline range discourages bacteria growth and undesirable
odor. Other fungicidal agents may also be included, for
example, mercury compounds or "Skane M-8", trade mark for
2-n-octyl-4-isothazolyn-3-one in the carrier solvent propylene
glycol.
- 17 -
l~9g47~
It will be understood that the compositions of the
invention are not necessarily limited to the auxiliary func-
tional agents named or to the precise amounts given for the
formation of plasticizer-free caulks and related types of
composition to provide the total compositions of the invention
with the auxiliary functional properties as described.
Compositions, according to the invention, may be
applied by conventional methods, for example, by brushing,
spraying or spreading with a spatula directly on the sub-
strate to thicknesses within the range from about 1/8th of aninch to about l/16th of an inch in one, two or three coats
depending on weather conditions and desired coating thickness.
A typical coating of the invention will generally "skin" in
abo~t half an hour, is rain-proof after about a couple of
hours and fully cured within about a week. Once cured, such
coating is resistant to weathering, mechanical stress, and
abrasion. The coating material adheres strongly to the sub-
strate and remains adhered thereto, after settling, despite
expansion and contraction or other movements, because of the
great elasticity of the coating. The coating may be laid down
on a scrim of woven fiberglass which gives the coating further
strength.
The coatings laid down from the coating materials of
the invention are competitive cost-wise with other materials.
For one example, a roof coating, according to the present
invention, is competitive with a built-up tar and gravel roof.
A sheath made up of a membrane formed from the coat-
ing compositions described over a concrete shell has remarkable
properties because of the inter-relationship between the con-
crete shell and the resin membrane. The shell being tenaciouslyadherent to the substrate, and when the latter is a plastic foam
acts as a primer permitting bonding of the resin emulsion
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1 L39~474
membrane to the foam surface to which it cannot effectively be
bonded by direct contact. Compatability between the surface of
the concrete shell and the resin emulsion membrane enables an
effective bond between the shell and membrane so that the sheath
is to all intents and purposes integral. The compatability is
brought about partly by the resin modification of the concrete
enabling it to take up moisture from the resin emulsion as it
dries and partly by the properties of the resin emulsion whose
capillary openings permit eventual escape of moisture from the
membrane itself and from beneath it. The membrane is, in effect,
an elastic hide that, besides protecting the concrete shell,
bridges away post-construction settling, cracking, vibration
or other forces in the underlying layers of the sandwich con-
struction described. The sheath has extraordinary bridging
moment considering its thinness.
Acrylic Emulsions
The literature on the acrylic emulsions referred to
above describes these emulsions as follows.
Rhoplex LC-67 is a 65% solids, low Tg polymer emulsion
binder that permits manufacture of plasticizer-free latex caulks.
The elimination of plasticizer from latex caulk formulations by
use of Rhoplex LC-67 binder yields a high-quality caulk that is
~ not subject to plasticizer migration problems such as glassing
and tackifying of paints with accompanying dirt pick-up, mildew
growth and loss of caulk flexibility on exterior exposure.
Caulks based on Rhoplex LC-67 retain the performance
advantages of current commercial caulk emulsions, Rhoplex LC-40
and Rhoplex LC-45, over conventional latex caulks in terms of
low shrinkage, initial low temperature flexibility, resistance
to discoloration on aging or on ultraviolet exposure, and dry
and wet adhesion to alkyd paints, glass, glazed ceramic and
concrete substrates. Utilizing our suggested starting point
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16399474
formulation, a latex caulk can be manufactured which exhibits
superior adhesion properties and superior elongation with satis-
factory tensile and recovery properties, even as compared to
the standard 3:1 pigment to binder ratio of Rhoplex LC-40 and
Rhoplex LC-45 based caulks.
Rhoplex LC-67 is an aqueous acrylic emulsion polymer
designed as an internally plasticized caulk vehicle with the
following typical properties:
Appearance Milky white liquid
Solids content, % 64.5 to 65.5
pH, as packed 4.8 to 5.4
Specific gravity 1.04
Density, lbs./U.S. Gal. 8.66
Minimum film-formation
temperature, C. Less than 0
Glass transition temperature -
(Tg), C. Approximately -50
Tukon hardness (KHN) Less than 1
Storage stability Protect from freezing
Rhoplex AC-707 is a high solids, acrylic emulsion
polymer. Several formulating and manufacturing advantages are
realized from utilizing a higher solids content emulsion. Less
emulsion must be handled and stored to produce a paint at a
~ given binder solids. More formulation latitude is available as
a result of less water being present with high solids emulsion.
For example, water included in lower solids emulsion could now
be used to predisperse other ingredients or could be used to
increase the grind volume. Higher volume solids p ints can be
formulated with satisfactory brushing properties while still
offering improved film build and higher hiding.
These are typical properties of Rhoplex AC-707, but
should not be considered specifications:
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1099479~
Solids content, % 65.0 - 0.5
pH 9.0 to 9.7
Viscosity, cps. Brookfield
No. 3 spindle - 60 RPM 300 to 700
Minimum film formation
temperature, C. 5 to 9
Tukon hardness, (KHN) ~1
Weight per gallon, lb. 8.97
Bulking value, gal./lb. - wet 0.1115
- dry 0.107
Mechanical stability
Waring blender - 5 cycles OK
Freeze-thaw stability - 5 cycles OK
Calcium ion stability OK
Oven stability - 10 days at 140F. OK
Emulsion stability of Rhoplex AC-707 is excellent and
no problems have been experienced with sedimentation or exces-
sive skinning as might be expected from the high solids content.
However, the usual precautions should be taken against the loss
of water from the surface when Rhoplex AC-707 is handled in bulk
storage tanks and drums. A humidification system is recommended
with bulk storage of any Rhoplex emulsion. Lids should be
replaced promptly on drums after use.
Paints formulated from Rhoplex AC-707 have properties
intermediate between Rhoplex AC-35 and Rhoplex AC-388 formula-
tions. The flow of paints based on Rhoplex AC-707 approaches
that of Rhoplex AC-388. Tne film build is slightly lower than
Rhoplex AC-388 but greater than Rhoplex AC-35. Adhesion to
chalk and gloss alkyd approach the performance of Rhoplex AC-35.
Although exterior exposure results are limited, we expect dura-
bility performance to be similar to Rhoplex AC-388.
When Rhoplex AC-707 is formulated into paints using
our recommended formulations based on Rhoplex AC-388, the spread
~99~4
rate averages up to about twenty percent higher than that of
paints formulated with Rhoplex AC-388.
