Structural barrier system

Abstract

An environmental barrier composition and method for forming a structural barrier system to seal structural openings such as doors and windows is provided. The composition includes a liquid rosin that is silyl-terminated polyether, a filler material, and a curing catalyst. The method includes applying the composition to a prepared through-hole in combination with flashing material at least along a bottom surface of the through-hole and installation of a window or door into the prepared through-hole to form a barrier system in which a continuous film can be easily inspected, is waterproof, meet air barrier requirements of ASTM E2178, has elastomeric properties, allows substrate expansion, contraction, and movement, does not shrink or lose volume as it cures, and cures rapidly with sufficient adhesion to transition flashing to incorporate into a designed drainage plane and allow integration of a continuous air barrier system where the barrier is at least semi-vapor-permeable.

Claims

1. A method of forming a structural barrier system for a through-hole in a wall, comprising: applying and spreading a coating composition in a liquid state to at least one prepared surface surrounding the through-hole in the wall to form a film of the coating composition on the at least one prepared surface, the coating composition comprising a liquid resin in the form of a silyl-terminated polyether and a curing catalyst; allowing the film of the coating composition to cure to form a waterproof flashing layer; and installing a framed window or door unit in the through-hole after the coating composition has cured.

2. The method of claim 1, further comprising after spreading the coating composition to a desired thickness, applying a sheet of flashing to a selected area of the surface surrounding the through-hole and at least partially on the coating composition.

3. The method of claim 1, wherein the film is spread to a thickness of about 10 to 14 mils.

4. The method of claim 1, wherein the film is spread to a thickness of about 12 mil.

5. The method as in claim 1 wherein the coating composition is applied to the least one prepared surface surrounding the through-hole in the wall using a caulking gun.

6. The method as in claim 1 wherein the coating composition is spread on the at least one prepared surface using a roller.

7. The method of claim 2 wherein the silyl-terminated polyether is polypropylene oxide capped at respective termini by a silyl group represented by: SiR.sup.1.sub.t(OR.sup.2).sub.3-t, wherein, t is 0, 1 or 2, R.sup.1 and R.sup.2 are the same or different and independently an alkyl group.

8. The method of claim 7 wherein the silyl group is dimethoxymethylsilyl.

9. The method of claim 1 wherein the coating composition further comprises calcium carbonate as a filler.

10. The method of claim 2 wherein the curing catalyst is an organotin compound.

Description

BRIEF DESCRIPTION OF THE DRAWINGS

(1) The foregoing and other features and advantages of the present invention will be more readily appreciated as the same becomes better understood from the detailed description of the invention when considered in conjunction with the following drawings, wherein:

(2) FIG. 1 is an isometric view of a structural barrier system for windows formed in accordance with one embodiment of the invention; and

(3) FIGS. 2-9 illustrate the installation procedure for constructing a structural barrier system for the window of FIG. 1.

DETAILED DESCRIPTION OF THE INVENTION

(4) In the following description, certain specific details are set forth in order to provide a thorough understanding of various disclosed embodiments. However, one skilled in the relevant art will recognize that embodiments may be practiced without one or more of these specific details, or with other methods, components, materials, etc. In other instances, well-known structures or components or both associated with window and door installations and other building installations, including but not limited to double hung windows, exterior siding, and electrical and plumbing details have not been shown or described in order to avoid unnecessarily obscuring descriptions of the embodiments.

(5) Unless the context requires otherwise, throughout the specification and claims that follow, the word comprise and variations thereof, such as comprises and comprising are to be construed in an open inclusive sense, that is, as including, but not limited to. The foregoing applies equally to the words including and having.

(6) Reference throughout this description to one embodiment or an embodiment means that a particular feature, structure, or characteristic described in connection with the embodiment is included in at least one embodiment. Thus, the appearance of the phrases in one embodiment or in an embodiment in various places throughout the specification are not necessarily all referring to the same embodiment. Furthermore, the particular features, structures, or characteristics may be combined in any suitable manner in one or more embodiments.

(7) Reference throughout this description to liquid is not intended in a limiting sense, but is rather intended to refer to an uncured state for the particular material being described, and does not necessarily mean the material has certain viscosity characteristics or is water based.

(8) Turning to the figures, FIG. 1 is an isometric illustration and partial cross-section of a structural barrier system 10, in this case for a window installation. Shown in FIG. 1 is typical wood framing construction for a through-hole 12 designed to receive the window unit 14. The rough opening formed by the through-hole 12 is framed at the top by a header 16, in this case shown formed by a plurality of wood framing members 18 supported on trimmer studs (not shown) that in turn are supported at the bottom by the window sill 20. Portions of cripple studs 22 are shown on top of the header 16 and below the sill 20. Exterior sheathing 24 and an interior wall board 26 are attached in place to the framing members.

(9) It is to be understood that the framing of the through-hole 12 for the window unit 14 is not limited to the particular construction shown in FIG. 1. The disclosed embodiments of the invention will have application to any rough opening formed by any type of construction. It is important, as with any window installation method that the rough opening formed by the through-hole 12 be prepared in a manner to ensure it is plumb, square, and dimensionally correct. It should also be smooth cut, clean and dry, with the sheathing 24 trimmed properly to support the window unit 12 and ensure long-term structural integrity of the exterior construction wall.

(10) In accordance with one embodiment, a liquid-applied flashing composition is applied in a solid-liquid state to the through-hole 12 structural members as described in detail below. The composition disclosed herein may be applied to virtually all construction wall substrates, most notably Concrete Masonry Unit block walls, though each must be tested to verify performance expectations with regard to adhesion and compatibility. The construction wall and the opening where a component, such as window or door, would be installed must be sound and fabricated according to existing building code requirements of the local jurisdiction.

(11) The substrate must be clean and free of foreign matter, water, or pollutants that may interfere with adhesion and long-term durability. Some substrates may require a primer or surface preparation procedure to maintain expected results of performance. The composition should not be applied to surfaces with standing or frozen water.

(12) The coating composition is based on a liquid resin and a filler material. The composition can be applied to a wide range of substrates in a liquid or semi-solid form, which then cures into a continuous film or membrane. Upon curing, the liquid resin forms a cross-linked elastomer, which provides the film with flexibility, conformability and a desired level of adhesion to the substrate. The filler material further imparts a variety of physical properties, including stability, rheology, curing and hardened tensile properties. Unlike the known liquid applied flash membrane systems, the composition described herein is free of volatile solvent. The film does not shrink or otherwise deform after curing because no solvent evaporation occurs.

(13) In one embodiment, the liquid resin is a silyl-terminated polyether. More particularly, the coating composition comprises a silyl-terminated polyether, a filler material, and a curing catalyst.

(14) Silyl-terminated polyethers are linear polyether chains capped at both termini with silyl groups. During curing, the silyl groups between polyether chains are coupled and the polyether chains become cross-linked to form the final elastomer.

(15) Polyethers, also referred to as polyalkylene oxides, typically comprise linearly arranged repeating units of alkylene oxides (RO), wherein R is an alkylene. Alkylene refers to a straight or branched divalent hydrocarbon chain consisting solely of carbon and hydrogen. The hydrocarbon chain is fully saturated and contains from one to six carbon atoms. The alkylene is attached to the rest of the molecule through single bonds at its respective terminal carbons. In a polyether, each alkylene is connected to two oxygen atoms. Exemplary alkylenes include, without limitation, methylene, ethylene, propylene, n-butylene, and the like. Preferred polyethers can be polyethylene oxide, polypropylene oxide, and the like.

(16) The molecular weight of the linear polyether chain can impact the physical properties (elasticity, durability, etc.) of the final cured film. The molecular weight is directly related to the number of the repeating units of alkylene oxide.

(17) The silyl terminal groups can be represented by SiR.sup.1.sub.t(OR.sup.2).sub.3-t, in which t is 0, 1 or 2. R.sup.1 and R.sup.2 are the same or different and independently an alkyl group containing 1 to 6 carbons. Alkyl refers to a linear or branched monovalent hydrocarbon radical containing no unsaturation. Exemplary alkyls include methyl, ethyl, propyl, and the like. The silyl group has at least one alkoxy group, i.e., OR.sup.2, which is responsible for coupling with another silyl group by forming a SiOSi linkage. An example of a silyl terminal group is when t is 1 and both R.sup.1 and R.sup.2 are methyl. The silyl terminal group can therefore be represented by Si(CH.sub.3)(OCH.sub.3).sub.2 (dimethoxymethylsilyl).

(18) The silyl-terminated polyether can be prepared by known methods in the art. For example, polyethers are typically terminated with hydroxy groups, which are reactive to silylating agents. An example of a silylating agent is ClSiR.sup.1.sub.t(OR.sup.2).sub.3, in which, R.sup.1, R.sup.2 and t are as defined herein.

(19) The silyl-terminated polyethers are also commercially available from, for example, Kaneka America Corporation (New York, N.Y.). In a preferred embodiment, the silyl-terminated polyether is Kaneka 303H, a polypropylene oxide capped with Si(CH.sub.3)(OCH.sub.3).sub.2 at both ends.

(20) The silyl-terminated polyether is typically present in the coating composition at about 15-60% by weight based on the total weight of the coating composition. More typically, it is present at about 20-40% by weight. More typically, it is present at about 25-30% by weight.

(21) The filler material impacts the processing, curing and the ultimate performance of the final film. A suitable filler material can be a mineral, which can be selected based on its particulate size, hardness, wettability and other physical properties. In one embodiment, calcium carbonate (CaCO.sub.3) can be used. CaCO.sub.3 is available under the trade name Duramite from lmerys International (Roswell, Ga.). The filler material can represent at about 35-60% by weight based on the total weight of the coating composition. More typically, the filler material is present at about 50% by weight.

(22) Suitable curing catalysts for cross-linking silyl-terminated polyethers include organometallic compounds. The organometallic compounds may be organotin compounds such as dimethyltin dilaurate, dibutyltin dilaurate, dibutyltin dimercaptide, dibutyltin oxide, dimethyltin dithioglycolate, dioctyltin dithioglycolate, and the like. In one embodiment, the curing catalyst is Fomrez SUL-11A (dibutyltin oxide), available from GE Silicones (Wilton, Conn.). Typically, the curing catalyst can be present at about 1-2.5% by weight based on the total weight of the coating composition. More typically, the curing catalyst is present at about 1.5%.

(23) The coating composition can comprise other additives to further optimize the performance of the film. These addictive include, without limitation, adhesion promoters, stabilizers (antioxidant, ultraviolet (UV) absorber, dehydrator), plasticizers, pigments, etc.

(24) The adhesion promoter can be an aminosilane such as N-(3-aminoethyl--aminopropyltrimethoxysilane, aminomethyltrimethoxysilane, aminopropyltriethoxysilane, etc. In one embodiment, the adhesion promoter is as N-(3-aminoethyl--aminopropyltrimethoxysilane, available under the trade name Silquest A-1120 from GE Silicones (Wilton, Conn.). The adhesion promoter is preferably added at about 0.7-2.5% by weight based on the total weight of the coating composition. More typically, the adhesion promoter is present at about 1.5%.

(25) A number of stabilizers can also be used to counter various adverse environmental factors, such as light, moisture and oxidization conditions. For example, light stabilizers that absorb broad spectrum of ultraviolet rays can be used. An example is Tinuvin328 (hydroxyphenylbenzotriazole) from Ciba Specialty Chemicals Co. (Terrytown, N.Y.). Another type of light stabilizers does not absorb ultraviolet rays, but acts to inhibit photo-initiated degradation of the film. Examples of this type of light stabilizer include hindered amine light stabilizers, which are derivatives of 2,2,6,6-tetramethyl piperidine. In one embodiment, the light stabilizer is Tinuvin765 (bis(1,2,2,6,6-pentamethyl-4-piperidyl) sebacate), which is available from Ciba Specialty Chemicals Co. (Terrytown, N.Y.). Each type of light stabilizer can typically be present at about 0.15-0.25% by weight based on the total weight of the coating composition, and more typically, at about 0.2%.

(26) Dehydrators are moisture-scavenging agents that prevent moisture-induced degradation of the film. In certain embodiments, the dehydrators can be alkoxysilane datives. One example of the dehydrator is Silquest A-171 (vinyltrimethoxysilane), available from GE Silicones (Wilton, Conn.). The dehydrator can typically be present in the coating composition at about 0.5-1% by weight based on the total weight of the coating composition, and more typically, at about 0.7%.

(27) Plasticizers can also be added to the coating composition to enhance the flexibility and durability of the film. They also act to increase the workability of the coating composition during the application process. Any known plasticizer can be used. In certain embodiment, phthalate-based plasticizers can be used because they are particularly compatible with polyethers, e.g., polypropylene oxide. Exemplary plasticizers include, without limitation, diisodecyl phthalate (DIDP), dissiononyl phthalate (DINP), butyl benzyl phthalate (BBzP), and the like. The plasticizer can typically be present at about 15-25% by weight based on the total weight of the coating composition, more typically, at about 18%.

(28) Pigments or colorants can also be added. If desired, the amount of the pigments can be controlled to maintain the opacity of the film. For example, the film formed by the cured coating composition can become opaque at the required thickness of about 12 mil (about 0.3 mm) for a liquid applied flash membrane, the opacity of the film allowing for an easy inspection. Typically, black and red pigments are used. For example, about 0.7-5% of red iron oxide pigments (HR-1209), available from Hoover Color Corp. (Hiwassee, Va.), can be used. Black pigments such as carbon black can also be added. For example, about 0.02-2% by weight of Monarch 280 from Cabot Corporation (Alpharetta, Ga.) can be used.

(29) Table 1 below lists the components of an exemplary coating composition according to one embodiment.

(30) TABLE-US-00001 TABLE 1 Components Material Description % by weight Kaneka 303H liquid resin 27 Duramite CaCO.sub.3 as filler 50 Fomrez Sul-11a organotin curing catalyst 1.5 Silquest A-1120 adhesion promoter 1.5 DIDP plasticizer 18 Tinuvin 328 ultraviolet absorber, light stabilizer 0.2 Tinuvin 765 hindered amine as a light stabilizer 0.2 Silquest A-171 dehydrator 0.7 Red Iron Oxide red pigments 0.8 Monarch 280 carbon black pigments 0.02

(31) Referring next to FIGS. 2-9, shown therein are the steps for applying the composition to the structural members surrounding the through-hole 12. The liquid-applied flashing membrane composition is stored in the solid liquid state in cartridges or bulk to be applied with standard caulk tools then brushed, rolled, or troweled to a desired coating thickness. As shown in FIG. 2, a cartridge 28 is loaded into a standard caulking gun 30. Prior to application, the structural surface may need to be primed. If so, readily commercially available primers can be used, such as Dow Corning 1200 Primer or Dow Corning 1205 Primer. The composition material 32 is applied to the exposed surface of the seal 20 and to the sheathing 24 on the horizontal sides of the through-hole 12. None of the composition material is applied to the sheathing 24 below the sill 20.

(32) The material 32 is then rolled with a roller 34 as shown in FIG. 3 to the desired thickness on the sill 20 and the sheathing 24. Due to the presence of a predetermined amount of red iron oxide pigment in the material 32, the material will remain transparent until approximately 11 mil thickness, where it begins to turn slightly opaque, and then it becomes completely opaque at 12 mil thickness. The opaqueness or transparency of the material 32 is dependent on thickness and not on its state, i.e., whether it is cured or uncured. This facilitates inspection to ensure that the material 32 is prepared to the correct thickness of 12 mil.

(33) It is to be understood that the dimensions set forth above are approximations, and variation can be made to accommodate particular applications. Thus, the material 32 can be applied in the range of 2 inches to 12 inches to the horizontal sides of the through-hole 12 on the sheathing 24 and it can slightly overlap the bottom of the through-hole 12 onto the sheathing 24 as shown in FIG. 2. The range of thickness can be 10-14 mil.

(34) After preparation with the roller 34, and while the liquid-applied flashing membrane material 32 is still uncured, a pre-creased fabric counter-flashing 36 is applied as shown in FIG. 4. More particularly, the flashing 36 is a transition material that is readily commercially available, such as the Sure Flash wrap available from Flashing Products, Inc. As shown in FIG. 4, the flashing 36 is dimensioned and positioned so that it extends the 9 inches to the sides of the through-hole 12 and extends above the sill 20 approximately 3 inches. The flashing 36 is then cut with a cutting tool 38 on each edge of the through-hole 12 down to the sill 20. This forms a flap 40 that is folded over onto the sill 20 as shown in FIG. 5. The roller 34 is used to press the flap 40 into the liquid-applied flashing membrane composition 32 while still in the uncured state. The flashing 36 is also rolled onto the material 32 applied to the sheathing 24 as shown in FIG. 6.

(35) Additional liquid-applied flashing material 32 is applied with the caulk gun 30 to the exposed side 42 and exposed surfaces of the header 16 and seal 20 as well as 9 inches on the sheathing 24 surrounding the entire through-hole 12. It is rolled with the roller 34 to the correct thickness. The fully prepared structural opening is shown in FIG. 9. It is to be understood that the portion of the structure that has been cut away is prepared in an identical fashion as described above. A cure time of 30 minutes or dry to the touch should be allowed before any window or door installation.

(36) Referring again to FIG. 1, in this case a window unit 14 is placed into the through-hole 12, which in this case has been prepared by brushing using brushes 44 as shown. Once the material 32 has dried, the through-hole 12 can be exposed to weather for extended periods without damage. The window unit 14 is preferably installed with drainage mesh or shims (not shown) at a bottom flange to allow for water management. A closed-cell foam backer rod is pushed into a gap around the interior side of the window unit 12 to ensure a proper depth-to-width ratio. This backer rod is readily commercially available and known to those skilled in the art. Hence, will not be described in detail herein. An interior seal 48 is then applied around the entire window frame, preferably using the caulk gun 30. The uncured sealant is preferably tooled with appropriate equipment (such as a spatula) to ensure proper contact with the window frame and the coated rough opening surfaces.

(37) The interior sealant is also readily commercially available, such as from applicant under the trade name WS-7100 and is applied at the same time as installation of the backer rod. Preferably the sealant 48 is applied with a pressure-operated device to form a uniform continuous speed, such as the caulk gun 30 described above. It is important that the sealant 48 be free of air pockets and embedded matter. Ideally a concave tooled joint is formed.

(38) The composition provides a continuous film that is easily inspected by becoming opaque at the required film thickness of 12 mils. The material is waterproof, meets air barrier requirements ASTM E2178, has elastomeric properties, including 400% stretch, to allow substrate expansion, contraction and movement, meets primer-less adhesion requirements to most substrates, emits no noxious odors of flammable solvents, does not shrink or lose volume as it cures, and resists weather damage for up to 6 months exterior exposure. The material cures rapidly enough, 15-30 minute tack-free, to not hinder construction schedule, has sufficient adhesion to transition flashing to incorporate into a designed drainage plane and allow integration with a continuous air barrier system. Preferably, the barrier is at least semi-vapor-permeable.

(39) The disclosed composition provides for a building structure consisting of exterior walls that include rough openings, having components such as windows and doors installed in such openings that is coated with a material that provides resistance to water and air intrusion. Ideally, the liquid-applied flashing material is waterproof and semi-permeable in that it permits vapor to pass therethrough to a certain extent. Vapor as used herein refers to water particles suspended in air.

(40) Typical sheet materials used in window and door installations are not vapor penetrable and tend to trap water. Metal has the disadvantage of corroding and provides thermal conduction, which can limit the life of a window or door installation. The liquid-applied flashing material of the embodiments described herein is weather durable, is not liquid penetrable, but it provides some vapor permeability, is bondable to a wall or building envelope, is easy to inspect, and provides a flexible structure that can stretch after it is dried. In addition, it can be installed using common tools, does not shrink as it cures, which avoids built-in tension, does not use solvents, and can bond to wet or moist substrates.

(41) All of the above U.S. patents, U.S. patent application publications, U.S. patent applications, foreign patents, foreign patent applications and non-patent publications referred to in this specification and/or listed in the Application Data Sheet, are incorporated herein by reference, in their entirety.

(42) From the foregoing it will be appreciated that, although specific embodiments of the invention have been described herein for purposes of illustration, various modifications may be made without deviating from the spirit and scope of the invention. Accordingly, the invention is not limited except as by the appended claims.