CA1198846A - Roof coating composition and construction - Google Patents
Roof coating composition and constructionInfo
- Publication number
- CA1198846A CA1198846A CA000338583A CA338583A CA1198846A CA 1198846 A CA1198846 A CA 1198846A CA 000338583 A CA000338583 A CA 000338583A CA 338583 A CA338583 A CA 338583A CA 1198846 A CA1198846 A CA 1198846A
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- coating composition
- transition temperature
- glass transition
- binder
- emulsion
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Abstract
ABSTRACT OF THE DISCLOSURE
A coating composition made up essentially of an intimate mixture of an internally plasticized caulk aqueous acrylic emulsion polymer and a high solids acrylic emulsion latex paint vehicle. Preferably the composition has as binder components an aqueous emulsion of an acrylic polymer having a glass transition temperature (Tg) from about -55°C to about 40°C, and an aqueous emulsion of an acrylic polymer having a glass transition temperature of from about +5°C to about +15°C, and contains a finely divided extender material.
A coating composition made up essentially of an intimate mixture of an internally plasticized caulk aqueous acrylic emulsion polymer and a high solids acrylic emulsion latex paint vehicle. Preferably the composition has as binder components an aqueous emulsion of an acrylic polymer having a glass transition temperature (Tg) from about -55°C to about 40°C, and an aqueous emulsion of an acrylic polymer having a glass transition temperature of from about +5°C to about +15°C, and contains a finely divided extender material.
Description
This invention relates to the construction o-E 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 Mo. 278,053, filed May 10, 1977, which claims primarily a structure, for example, a roof having a protective sheath made up of an insulating blanket carrying 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 coating composition used in forming such a membrane and to a binder for the coating composition, and to methods of making them.
A specific utility of the invention is in providing an improved form of Bermuda xoof. 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 recogniæed by anybody who has visited Bermuda.
A~plying 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 3~ sheath. ~e sheath is made up o~ a hard, essentially reinforced concrete shell adhering tenaciously to the top surface o~ -~he shinylesand an essentially rubber~-textured membrane covering the shell and adhering tenaciously to it. Critical characteris-tics of the sheath materials and advantageous detailed features of construction which may be accomplished 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 combination with other structural and coating material. For example, U.S.
Patent 3,389,518 Horbach (1968) which, at first glance, might ` be considered analogous to the applicant's development, is direc~ed to cladding a flat surfaced wall or roof, employing a plurality of resilient thermo-insulating cellular polystyrene plates to form an insulating layer covering the wall or roof support. Over the insulating layer there is applied a con-tinuous intermediate layer consisting essentially o~ a synthetic resin having a reinforcing glass fabric embedded in it. The patentee describes the intermediate 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 o~f corrosive hydrogen chloride. Polyvinyl chloride film blacXens and brittles and requires plasticizers for usable flexibility. Butadiene styrene polymers oxidize in ultraviolet light with severe yellowing and embrittlement due to cross-linkin~. They require the use of antioxidantsO Propionic acidesters and polyvinyl acetates hydrolize in the presence of moisture and alkaliO
The construction described in Application 278,053 contrasts with the teachings of this and other prior art patents by its special protect~ve load-bearing and weatherproof sheath in which there are married together a hard essentially rein-forced concrete shell co~ering 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. ~his construction is desirably provided by a finishing st~ip which extends about the 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 blan~et 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 undersurf~ce of the finishiny strip. The downwardly and inwardly extending parts of the bonnet constitute the ~irdle which supplement the tenacious surface adherence of the roof covering to the deck in anchoring it to the superstructure of the building.
'rhe blanket i,s 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 ~ace~ The body has one end pro-vided with a flange protruding therefrom and the other with a ~ r~cess to interfit with the flange and recess of adjacent shingles. ~he 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. I'hey 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 -35~ to a~out -45C. con-taining from about 50% to about 60% by weight of fi~ely divided extender.
The membrane and shell are married to~ether as an essentially integral unit with the shell providing load-bearin~
strength and the membrane sealing the shell from the outside and preserving properties of the relatively thin concrete which could be otherwise deteriorated hy e~posure to the elements.
i''~` - 4 -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 m~mbrane formed wi-th 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 illustratin~ 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 blanXet, 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 along the line 6-6 of Figure 1 through the eaves part of the roof, Fiyure 7 is an enlarged fragmentary cross-section along the line 7~7 of Figure 1 through the verge of the roof; and Figure 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 substra-te 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 otherwiseO A preferred adhesive is a water-based foam and tile adhesive sold under the trade mark "Nova 96" by Coatings International Limited of Hamilton, Bermuda.
In the example roof, the shingles 30 are of the form sho~n in Figuxes 3 to 5. Each shingle is tapered and has an 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 m; n;mi 7es the overall expansion and contraction acrGss the roof with temperature changes.
The synthetic insulating foam material of the shingles, because of its ~oids 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 insulatlng blanket D is pro-tected, according to the invention, by the adhes~ve 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 preferahly ~ormed by spreading over the continuous surface of the roof B a coating of spread-able hydraulic ce~ent-aggregate mix reinforced with ~inely divided inert material and short glass fibers. The coating is 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 agueous 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 o~ the strip a pocket to receive a ~oncrete 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 ~2.
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 these surfaces. The shell E is thus anchored to the edge of the xoof and acts to protect and retain the edges of the eaves shingles 30. '~he 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 agai.nst ingress of moisture and further anchor-ing to the roof deck the shingles of khe insulating blanket D
and the entire shea-th 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 f~r 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 been shown as sheets 25 of p:lywood, other structural materials can be employed, for example, tongue-and-groove tirnber, corrugated iron, or g concxete.
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 rnolding, 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 descrihed, for example, in the booklet l'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-carryin~ 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, prefera~ly glass fiber, modified by the use of from about 5/O to about 20% of a synthetic resin latex cement modifier to provide it with high impact str~ngth (at least 6 to 16 inch pounds), high flexural strength, thin section strength, high tensile strength (greater than 100 pounds per square 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 fle~ural strength andadhesion necessary to resist freeze-thaw liftiny and the dur-ability to ~ithstand ~ea-therin~ and ultravialet degradation.
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 Cementi',"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 "~hoplex E-330 Cement Mortar Modifier", Rohm and Haas, August 1974, or "Rhoplex MC-76"
~solids 4~% - 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 ag~regate 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 wor~ing charac-teristics.
A preferred concrete is made by mixing together a first product including Portland cement, short glass fibers, silica sand, powdered limestone, wetting agents and defoarners with a second product including a liquid acrylic aggregate additive containing enough water for a concrete mixO
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. Th~ modified concrete reaches a~out 90% of its ultimate strength in about 48 hours and cures after about seven days.
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 an~ having a thickness within the range from about O.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~ g 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 al]owing 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 Characteri2ation of Polymers" by Rohm and Haas (CM~106 D/cd) and "Plastics in the Modern World" by Couzens and Yarsley, Penguin Books Ltd. (196~3, pages 217 and 218.
Preferred formulations are as follows, the percentages being given by weight:
Total resin emulsion so]ids 44%
Total filler and pigment 51%
Miscellaneous constituents 5%
~he composition, as manufactured, should have a con-sistency within the range from about 5 to about 50 seconds as measured by the Semco r--nn;ng test referred to as follows in "Forrnulating Guide for ~crylic 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-lng gun fitted with a Semco nozzle with a 1/8th inch 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 consistenc~ of 25. The consistency may be adjusted with water or a ~lycol for spray or ~rush application and open timeO
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 m;nirm1m of about two hours and a maximum of about 12 hours depending on weather conditions.
The membrane should not be applied till 4 or ~ hours at the earliest, preferably about 12 hours after the concrete is applied.
In more detail "Rhoplex LC-67" is described in the brochure o-f Rohm and Haas entitled "Rhoplex LC-67 Acrylic Emulsion for Plasticizer-Free Latex ~aulks" ~19763. As des~
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 accornpanying dirt pick-up, mildew gro~th, 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 ~;n;ml~m film-formation temperature, C~ less than 0 Glass transition temperature (Tg), C. approximately -50 Tu~on hardness (KM~) 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 ext~nder or filler to provide good caulk performance in terms of caulk rheological and ~ 14 ~
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 ~Jhich contributes to forming a stable homogeneous and creamy low consistency caul~, a secondary pigment dispersion which is essential to ~orm 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 coa-ting characteristics.
"Rhoplex AC-707" is described in the Rohm and Haas booklet "Rhoplex AC-707 High Solids Acrylic Emulsion Vehicle~
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 No. 3 spindle 60 RP~ 300 to 700 ~;nirmlm ~ilm fo~ation temperature, C. -~ 10C. to + 12C.
~ukon hardness, KH~ C1 Weight per gallon, lb. 8.97 Bulking value, gal./lb. -~ wet 0.1115 - dry 0.107 Mechanical stability Waring Blender - 5 ~ycles OK
Freeze-thaw stability ~ 5 cycles OK
Calcium ion stability OK
Oven stability - 10 days at 140F. OK
, ap~roximately ~ 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 ~ur~ace of the emulsion, when handled in bulk storage tanks and drums.
- A humidification system is re~omm~nded 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 pi~ment dispersant present in an amount from ~bout 0.5% to about 0.8%, "Oratan 850" (trade mark) a secondary pigment dis-persant in an amount from 0.05% to a~out 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; rut.ile titanium dioxide or other pigments or equally fine~y ground material or materials in an amount within the range from 0O7% to about 2~0%o A11 these amounts are 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-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 rrom 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 seq~ence of addition o-f the constituents is not critical, a preferred sequence is to mix the first and second binders together first. Half the defoamer ~ay 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 mi~ture of the resin with the extenders is ~uite 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 ran~e discourages bacteria growth and undesirable odox. Other fungicidal agents may also be included, for example, mercury compounds or "Skane M-8", trade mark for
This application is a division of Application Serial Mo. 278,053, filed May 10, 1977, which claims primarily a structure, for example, a roof having a protective sheath made up of an insulating blanket carrying 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 coating composition used in forming such a membrane and to a binder for the coating composition, and to methods of making them.
A specific utility of the invention is in providing an improved form of Bermuda xoof. 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 recogniæed by anybody who has visited Bermuda.
A~plying 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 3~ sheath. ~e sheath is made up o~ a hard, essentially reinforced concrete shell adhering tenaciously to the top surface o~ -~he shinylesand an essentially rubber~-textured membrane covering the shell and adhering tenaciously to it. Critical characteris-tics of the sheath materials and advantageous detailed features of construction which may be accomplished 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 combination with other structural and coating material. For example, U.S.
Patent 3,389,518 Horbach (1968) which, at first glance, might ` be considered analogous to the applicant's development, is direc~ed to cladding a flat surfaced wall or roof, employing a plurality of resilient thermo-insulating cellular polystyrene plates to form an insulating layer covering the wall or roof support. Over the insulating layer there is applied a con-tinuous intermediate layer consisting essentially o~ a synthetic resin having a reinforcing glass fabric embedded in it. The patentee describes the intermediate 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 o~f corrosive hydrogen chloride. Polyvinyl chloride film blacXens and brittles and requires plasticizers for usable flexibility. Butadiene styrene polymers oxidize in ultraviolet light with severe yellowing and embrittlement due to cross-linkin~. They require the use of antioxidantsO Propionic acidesters and polyvinyl acetates hydrolize in the presence of moisture and alkaliO
The construction described in Application 278,053 contrasts with the teachings of this and other prior art patents by its special protect~ve load-bearing and weatherproof sheath in which there are married together a hard essentially rein-forced concrete shell co~ering 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. ~his construction is desirably provided by a finishing st~ip which extends about the 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 blan~et 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 undersurf~ce of the finishiny strip. The downwardly and inwardly extending parts of the bonnet constitute the ~irdle which supplement the tenacious surface adherence of the roof covering to the deck in anchoring it to the superstructure of the building.
'rhe blanket i,s 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 ~ace~ The body has one end pro-vided with a flange protruding therefrom and the other with a ~ r~cess to interfit with the flange and recess of adjacent shingles. ~he 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. I'hey 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 -35~ to a~out -45C. con-taining from about 50% to about 60% by weight of fi~ely divided extender.
The membrane and shell are married to~ether as an essentially integral unit with the shell providing load-bearin~
strength and the membrane sealing the shell from the outside and preserving properties of the relatively thin concrete which could be otherwise deteriorated hy e~posure to the elements.
i''~` - 4 -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 m~mbrane formed wi-th 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 illustratin~ 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 blanXet, 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 along the line 6-6 of Figure 1 through the eaves part of the roof, Fiyure 7 is an enlarged fragmentary cross-section along the line 7~7 of Figure 1 through the verge of the roof; and Figure 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 substra-te 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 otherwiseO A preferred adhesive is a water-based foam and tile adhesive sold under the trade mark "Nova 96" by Coatings International Limited of Hamilton, Bermuda.
In the example roof, the shingles 30 are of the form sho~n in Figuxes 3 to 5. Each shingle is tapered and has an 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 m; n;mi 7es the overall expansion and contraction acrGss the roof with temperature changes.
The synthetic insulating foam material of the shingles, because of its ~oids 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 insulatlng blanket D is pro-tected, according to the invention, by the adhes~ve 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 preferahly ~ormed by spreading over the continuous surface of the roof B a coating of spread-able hydraulic ce~ent-aggregate mix reinforced with ~inely divided inert material and short glass fibers. The coating is 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 agueous 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 o~ the strip a pocket to receive a ~oncrete 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 ~2.
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 these surfaces. The shell E is thus anchored to the edge of the xoof and acts to protect and retain the edges of the eaves shingles 30. '~he 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 agai.nst ingress of moisture and further anchor-ing to the roof deck the shingles of khe insulating blanket D
and the entire shea-th 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 f~r 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 been shown as sheets 25 of p:lywood, other structural materials can be employed, for example, tongue-and-groove tirnber, corrugated iron, or g concxete.
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 rnolding, 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 descrihed, for example, in the booklet l'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-carryin~ 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, prefera~ly glass fiber, modified by the use of from about 5/O to about 20% of a synthetic resin latex cement modifier to provide it with high impact str~ngth (at least 6 to 16 inch pounds), high flexural strength, thin section strength, high tensile strength (greater than 100 pounds per square 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 fle~ural strength andadhesion necessary to resist freeze-thaw liftiny and the dur-ability to ~ithstand ~ea-therin~ and ultravialet degradation.
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 Cementi',"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 "~hoplex E-330 Cement Mortar Modifier", Rohm and Haas, August 1974, or "Rhoplex MC-76"
~solids 4~% - 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 ag~regate 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 wor~ing charac-teristics.
A preferred concrete is made by mixing together a first product including Portland cement, short glass fibers, silica sand, powdered limestone, wetting agents and defoarners with a second product including a liquid acrylic aggregate additive containing enough water for a concrete mixO
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. Th~ modified concrete reaches a~out 90% of its ultimate strength in about 48 hours and cures after about seven days.
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 an~ having a thickness within the range from about O.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~ g 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 al]owing 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 Characteri2ation of Polymers" by Rohm and Haas (CM~106 D/cd) and "Plastics in the Modern World" by Couzens and Yarsley, Penguin Books Ltd. (196~3, pages 217 and 218.
Preferred formulations are as follows, the percentages being given by weight:
Total resin emulsion so]ids 44%
Total filler and pigment 51%
Miscellaneous constituents 5%
~he composition, as manufactured, should have a con-sistency within the range from about 5 to about 50 seconds as measured by the Semco r--nn;ng test referred to as follows in "Forrnulating Guide for ~crylic 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-lng gun fitted with a Semco nozzle with a 1/8th inch 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 consistenc~ of 25. The consistency may be adjusted with water or a ~lycol for spray or ~rush application and open timeO
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 m;nirm1m of about two hours and a maximum of about 12 hours depending on weather conditions.
The membrane should not be applied till 4 or ~ hours at the earliest, preferably about 12 hours after the concrete is applied.
In more detail "Rhoplex LC-67" is described in the brochure o-f Rohm and Haas entitled "Rhoplex LC-67 Acrylic Emulsion for Plasticizer-Free Latex ~aulks" ~19763. As des~
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 accornpanying dirt pick-up, mildew gro~th, 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 ~;n;ml~m film-formation temperature, C~ less than 0 Glass transition temperature (Tg), C. approximately -50 Tu~on hardness (KM~) 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 ext~nder or filler to provide good caulk performance in terms of caulk rheological and ~ 14 ~
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 ~Jhich contributes to forming a stable homogeneous and creamy low consistency caul~, a secondary pigment dispersion which is essential to ~orm 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 coa-ting characteristics.
"Rhoplex AC-707" is described in the Rohm and Haas booklet "Rhoplex AC-707 High Solids Acrylic Emulsion Vehicle~
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 No. 3 spindle 60 RP~ 300 to 700 ~;nirmlm ~ilm fo~ation temperature, C. -~ 10C. to + 12C.
~ukon hardness, KH~ C1 Weight per gallon, lb. 8.97 Bulking value, gal./lb. -~ wet 0.1115 - dry 0.107 Mechanical stability Waring Blender - 5 ~ycles OK
Freeze-thaw stability ~ 5 cycles OK
Calcium ion stability OK
Oven stability - 10 days at 140F. OK
, ap~roximately ~ 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 ~ur~ace of the emulsion, when handled in bulk storage tanks and drums.
- A humidification system is re~omm~nded 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 pi~ment dispersant present in an amount from ~bout 0.5% to about 0.8%, "Oratan 850" (trade mark) a secondary pigment dis-persant in an amount from 0.05% to a~out 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; rut.ile titanium dioxide or other pigments or equally fine~y ground material or materials in an amount within the range from 0O7% to about 2~0%o A11 these amounts are 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-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 rrom 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 seq~ence of addition o-f the constituents is not critical, a preferred sequence is to mix the first and second binders together first. Half the defoamer ~ay 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 mi~ture of the resin with the extenders is ~uite 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 ran~e discourages bacteria growth and undesirable odox. 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 ~lycol~
It will be understood that the compositions of the invention are not necessarily limited to the auxiliary func-tional agents named or to the pxecise 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 l/~th 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 about half an hour, is rain-proof after about a couple of hours and fully cured within about a week. Once cured, such coating i5 résistant 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 descxibed over a concrete shell has remarkable propexties because of the inter-relationship between the con-
It will be understood that the compositions of the invention are not necessarily limited to the auxiliary func-tional agents named or to the pxecise 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 l/~th 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 about half an hour, is rain-proof after about a couple of hours and fully cured within about a week. Once cured, such coating i5 résistant 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 descxibed over a concrete shell has remarkable propexties because of the inter-relationship between the con-
3~ crete shell and the resin membrane. The shell beiny tenaciouslyadherent to the substrate, and when the latter is a plastic foam acts as a primer permitting bonding of the resin emulsion ~ 1~ --mernbrane 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 mernbrane 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 ernulsion as it dries and partly by the properties of the resin emulsion whose caplllary openings permit eventual escape of moisture from the mer~brane itself and from beneath it. The mernbrane 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.
~ hoplex 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 su~ject to plasticizer migration problems such as glassing and tackifying of paints with accompanying dirt pick-up, rnildew growth and loss of caulk flexibility on exterior exposure.
Caulks based on Rhoplex LC-~7 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 ternperature flexibility, resistance to discoloration on aging or on ultraviolet exposure, and dry and wet adhesion to alkyd paints, glass, glazed ceramic and concrete substratesO UtiLizing our sug~ested starting point 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 pigrnent to binder ratio of ~hoplex 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:
~ppearance Milky white liquid Solids content, % 64.5 to 65.5 pH, as packed ~.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 freeæing Rhoplex AC-707 is a high solids, acrylic ~nulsion polymer. Several formulating and manufacturing advantages are realized from utilizing a higher solids content emulsion. ~ess 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 ernulsion could now be used to predispexse 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 irnproved film build and higher hiding.
These are typical properties of Rhoplex AC-7~7, but should not be considered specifications:
Solids content, % 65.0 + 0.5 pH 9.0 to 9.7 Viscosity, cps. Brookfield No. 3 spindle - 60 RP~ 300 to 700 ~;n1m1lm film formation temperature, C. 5 to 9 Tukon hardness, ~K~) ~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 ernulsion. 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. ~ne 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 recor~mended formulations based on Rhoplex AC-388, the spread - 21 ~
rate averages up to about twenty percent higher than that of paints formulated with Rhoplex AC-388.
~2 -
Acrylic Emulsions The literature on the acrylic emulsions referred to above describes these emulsions as follows.
~ hoplex 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 su~ject to plasticizer migration problems such as glassing and tackifying of paints with accompanying dirt pick-up, rnildew growth and loss of caulk flexibility on exterior exposure.
Caulks based on Rhoplex LC-~7 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 ternperature flexibility, resistance to discoloration on aging or on ultraviolet exposure, and dry and wet adhesion to alkyd paints, glass, glazed ceramic and concrete substratesO UtiLizing our sug~ested starting point 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 pigrnent to binder ratio of ~hoplex 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:
~ppearance Milky white liquid Solids content, % 64.5 to 65.5 pH, as packed ~.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 freeæing Rhoplex AC-707 is a high solids, acrylic ~nulsion polymer. Several formulating and manufacturing advantages are realized from utilizing a higher solids content emulsion. ~ess 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 ernulsion could now be used to predispexse 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 irnproved film build and higher hiding.
These are typical properties of Rhoplex AC-7~7, but should not be considered specifications:
Solids content, % 65.0 + 0.5 pH 9.0 to 9.7 Viscosity, cps. Brookfield No. 3 spindle - 60 RP~ 300 to 700 ~;n1m1lm film formation temperature, C. 5 to 9 Tukon hardness, ~K~) ~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 ernulsion. 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. ~ne 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 recor~mended formulations based on Rhoplex AC-388, the spread - 21 ~
rate averages up to about twenty percent higher than that of paints formulated with Rhoplex AC-388.
~2 -
Claims (5)
1. A coating composition having as a binder matrix a non-plasticized latex of an acrylic elastomeric-type polymer having a Tg within the range from about -35°C. to about -45°C. containing from about 50% to about 60% by weight of finely divided extender, said binder being made up of an intimate mixture of a first component which is an aqueous acrylic copolymer emulsion for plasticizer-free caulks having a glass transition temperature (Tg) of from about -40°C. to about -45°C. and a second component which is a high solids aqueous acrylic emulsion vehicle having a glass transition temperature (Tg) of from about +5°C. to about +15°C.
2. A coating composition, as defined in claim 1, wherein the extender material is calcium carbonate.
3. A coating composition, as defined in claim 1, wherein the extender is calcium carbonate in the form of particles ranging in size from 2 to 12 microns and having an average particle size of 4 to 10 microns.
4. A coating composition, as defined in claim 1, having a consistency of 5 to 20 seconds as measured by the Semco running test.
5. A substrate coated with a coating composition, comprising an intimate mixture of a first binder component which is an aqueous acrylic copolymer emulsion for plasti-cizer-free caulks having a glass transition temperature (Tg) of from about -40°C to about -45°C, a second binder component which is a high solids aqueous acrylic emulsion vehicle having a glass transition temperature (Tg) of from about +5°C to about +15°C, and a finely divided extender material in an amount from 50% to 60% by weight, and which provides a coating film having a glass transition temperature of from -35°C to -45°C.
Applications Claiming Priority (2)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| GB19410/76A GB1534043A (en) | 1976-05-11 | 1976-05-11 | Coating composition |
| CA278,053A CA1070970A (en) | 1976-05-11 | 1977-05-10 | Roof coating composition and construction |
Publications (1)
| Publication Number | Publication Date |
|---|---|
| CA1198846A true CA1198846A (en) | 1985-12-31 |
Family
ID=25668508
Family Applications (2)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| CA000338583A Expired CA1198846A (en) | 1976-05-11 | 1979-10-26 | Roof coating composition and construction |
| CA338,584A Expired CA1099474A (en) | 1976-05-11 | 1979-10-26 | Roof coating composition and construction |
Family Applications After (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| CA338,584A Expired CA1099474A (en) | 1976-05-11 | 1979-10-26 | Roof coating composition and construction |
Country Status (1)
| Country | Link |
|---|---|
| CA (2) | CA1198846A (en) |
-
1979
- 1979-10-26 CA CA000338583A patent/CA1198846A/en not_active Expired
- 1979-10-26 CA CA338,584A patent/CA1099474A/en not_active Expired
Also Published As
| Publication number | Publication date |
|---|---|
| CA1099474A (en) | 1981-04-21 |
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| MKEX | Expiry |