CONTAINED FOAM ENVELOPE FOR INSULATING AND SEALING LARGE VOLUMES
20170136664 ยท 2017-05-18
Inventors
- Robert J. O'Leary (Newark, OH, US)
- Harry Alter (Granville, OH, US)
- Desmond J. VanHouten (Pataskala, OH, US)
Cpc classification
B29C44/188
PERFORMING OPERATIONS; TRANSPORTING
B29K2995/0016
PERFORMING OPERATIONS; TRANSPORTING
B29L2031/776
PERFORMING OPERATIONS; TRANSPORTING
B29C44/185
PERFORMING OPERATIONS; TRANSPORTING
B29K2075/00
PERFORMING OPERATIONS; TRANSPORTING
E04B2001/7679
FIXED CONSTRUCTIONS
B29L2031/10
PERFORMING OPERATIONS; TRANSPORTING
E04B1/7654
FIXED CONSTRUCTIONS
International classification
Abstract
A system for sealing large volumes or gaps includes a flexible envelope that can assume the shape of the volume when filled with a foaming composition that expands the envelope to the boundaries of the volume. The foaming composition may be integral with the envelope or delivered in bulk by an external device. The foaming composition may be one or multiple parts, typically two parts such as a poly isocyanate and a polyols, in which case it is necessary to keep the two parts separate until foaming is desired. Separation may be accomplished by providing multiple compartments that deliver components via a mixing device into the interior. The envelope may include ribs for structural strength and shaping, and leak pores around its perimeter to enhance bonding and sealing. It may also include perforations for bulk, modular seals or for separation of portions of the envelope to seal irregular shapes.
Claims
1-8. (canceled)
9. A method for sealing or insulating a large volume, the method comprising: placing within the large volume against at least one substrate; a self contained system for sealing or insulating a large volume, the system comprising: an envelope having walls defining an interior and at least one separate compartment in fluid communication with the interior, the compartment housing at least one component of a foaming composition; and an activation trigger configured, upon activation, to mix the components of the foaming composition and deliver them to the interior of the envelope to initiate a foaming reaction within the envelope and activating the trigger to initiate the foaming reaction.
10. The method of claim 9 wherein a retrofit envelope is inserted into an enclosed volume space through a smaller orifice in one of the substrate surfaces.
11. The method of claim 10 wherein the envelope is first rolled up for insertion through a smaller orifice and as the foaming composition expands, the envelope unrolls to fill the volume.
12. The method of claim 9 wherein the step of activating the trigger comprises depressing a plunger.
13. The method of claim 9 wherein the step of activating the trigger comprises pinch rolling a flexible sided compartment of the envelope.
14-24. (canceled)
25. A method for sealing or insulating a large volume comprising: placing an envelope within the large volume against at least one substrate; the envelope having walls defining an interior, and an exterior fitment in one wall, the fitment being in fluid communication with the interior of the envelope and being dimensioned to sealingly engage the outlet of a delivery device for connecting to a source of components of a foaming composition and delivering the foaming composition to the interior of the envelope through the fitment; and a matrix disposed in the envelope interior adjacent to the fitment to mix components of a foaming composition, delivering a quantity of components of the foaming composition to the interior of the envelope through a delivery device connected to the source of components of the foaming composition and to the exterior fitment, whereby the components are mixed within the matrix to initiate a foaming reaction within the envelope.
26. The method of claim 25 wherein the foaming composition is a two part foaming composition.
27. The method of claim 25 wherein the matrix within the interior of the envelope further comprises an impervious backing that forces the foaming composition delivered to the fitment to disperse into the interior in a direction non-parallel to the delivery through the fitment.
28-32. (canceled)
33. A method for sealing or insulating a large volume using an envelope system, the envelope system comprising a plurality of envelopes each having walls defining an interior and an exterior fitment in fluid communication with the interior; the fitment being adapted to receive a delivery device for delivering components of a foaming composition to the interior of the envelope; each envelope being joined to at least one other envelope along a common side, the common side having a series of perforations for separating one envelope from the other the method comprising: separating a portion of the plurality of envelopes as needed to create a a modified envelope system to fit an irregular volume; placing the modified envelope system within the large volume against at least one substrate; delivering to the interior of the envelope through the delivery device connected to the source of components of a foaming composition and to the exterior fitment a quantity of components of the foaming composition mixed to initiate a foaming reaction within the envelope.
34. The method of claim 33 wherein the foaming composition is a two-part composition and the two parts are mixed prior to delivery to the interior of the envelope.
35. The method of claim 33 further comprising a matrix disposed in the envelope interior adjacent the fitment, and wherein the foaming composition is a two-part composition and the two parts are mixed in the matrix within the interior of the envelope.
Description
BRIEF DESCRIPTION OF THE DRAWINGS
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[0041]
DETAILED DESCRIPTION OF THE INVENTION
[0042] Unless defined otherwise, all technical and scientific terms used herein have the same meaning as commonly understood by one of ordinary skill in the art to which the invention belongs. Although any methods and materials similar or equivalent to those described herein can be used in the practice or testing of the present invention, the preferred methods and materials are described herein. All references cited herein, including published or corresponding U.S. or foreign patent applications, issued U.S. or foreign patents, and any other references, are each incorporated by reference in their entireties, including all data, tables, figures, and text presented in the cited references.
[0043] The term R-value is the commercial unit used to measure the effectiveness of thermal insulation and is the reciprocal of its thermal conductance which, for slab materials having substantially parallel faces, is defined as the rate of flow of thermal energy (BTU/hr or Watt) per unit area (square foot=ft.sup.2 or square meter=m.sup.2) per degree of temperature difference (Fahrenheit or Kelvin) across the thickness of the slab material (inches or meters). Inconsistencies in the literature sometimes confuse the intrinsic thermal properties resistivity, r, (and conductivity, k), with the total material properties resistance, R, (and conductance, C), the difference being that the intrinsic properties are defined as being per unit thickness, whereas resistance and conductance (often modified by total) are dependent on the thickness of the material, which may or may not be 1 unit. This confusion, compounded by multiple measurement systems, produces an array of complex and confusing units the most common of which are:
TABLE-US-00001 English (inch-pound) Metric/SI units Intrinsic resistivity, r (conductivity, k, is reciprocal)
[0044] For ease of comparisons of materials of differing thicknesses, the building industry sometimes reports thermal resistance (or conductance) per unit thickness (e.g. per inch) effectively converting it to thermal resistivity (conductivity), but retains the traditional symbol, R or R-value.
[0045]
[0046] In similar fashion, a two-story unit has a similar large gap joist space 11, shown in the upper part of
[0047]
[0048] It is customary in cooler climates to install insulation in the interjoist spaces between conditioned area 82 and unconditioned area 70. However, typical insulation does little to prevent air leaks and drafts from flowing through the interjoist spaces right along the joists. Sealing as used herein refers to the prevention or hindering of the movement of air such as drafts (i.e. convection) that can move through cavities, gaps, and poorly sealed seams whereas insulating refers to the prevention or hindering of all forms of heat transfer, including convection, conduction and radiation. Thus, sealing is a specialized case of insulating. Sealing is also important for noise reduction. The present invention addresses the shortcomings of using only insulation in interjoist spaces.
[0049] Some typical large volume areas are discussed above and illustrated in
[0050] While the above examples of large volumes, cavities or gaps are given, it should be appreciated that these are not the only embodiments of large gaps. Large gaps do not have any particular minimum dimensions or shape, and other large gaps may also be envisioned and suitable for sealing using the envelope seals described herein. Generally, however, gaps or cavities are considered large if they encompass a volume of at last 6 cubic inches, more likely at least 12, 24, 48 or 64 cubic inches, and they may be as large as several cubic feet. Although discussed in terms of volume and cavities, the depth dimension is more applicable when additional R-value or insulation is desired. For sealing alone, a very thin envelope having just two dimensions is suitable, and one might describe it in terms of the area of the gap, but as a practical matter some insulation effect is often desired as well and the envelope will have some thickness and volume to provide this. Sealing or insulating or both are all aspects of the invention.
[0051] A large volume or gap is always bounded by a substrate on at least one side and usually, at least 2, 3 or more substrate/sides. Interjoist gaps are bounded by the two joists as well as one or more of a floor, a ceiling, a top plate, a sill plate and optionally by a band joist. Masonry gaps mentioned above are bounded by the masonry and a rafter or other framing structure as substrates. Similarly, a chase is bounded by substrate walls that form the chase. These substrates provide surfaces to which envelope seals may be lodged against or attached.
[0052] In some embodiments, the large volumes or gaps may not be in residential or building construction at all, but may occur in automotive, aircraft, marine or other vehicles, or in appliances such as dishwashers, dryers, ovens, refrigerators and the like. Any cavity, void or gap that needs to be sealed or insulated or both is potentially a large volume gap in accordance with the invention.
[0053] In order to fill and seal the large gaps described above, the invention provides in a first integral or self-contained embodiment an envelope or bag that already contains a quantity of a foaming composition that can be triggered externally to initiate a foaming reaction internally within the envelope to expand it to fill and seal the large volume. The foaming composition may be thought of as a unit dose for the intended envelope or container. Foaming compositions are described below. They are typically, though not necessarily, made in two parts which, like epoxies, are kept separated until ready for use. Activation triggers are used to combine the two parts to initiate the foaming reaction. In a different, bulk embodiment the bag or envelope does not initially contain the foaming composition or an activation device, but instead contains a fitment into which a foaming composition can be injected. The foaming compositions, if two-part, may be mixed in the delivery device just prior to injection into the envelope, or they may be delivered unmixed and mixed within a matrix inside the envelope. Several embodiments of the envelope or bag, including activation triggers and fitments, are described below in connection with multiple embodiments and with reference to the drawing figures.
Envelopes and Activators
[0054] The term envelope is synonymous with bag, sac, bladder and similar terms that convey a sealed or sealable container with flexible walls. The envelope may be relatively flat, or it may have side walls or pleats to give it some depth when expanded. The envelope walls may be elastic and stretch to expand and conform to the volume space it is designed to fill, yet it should be strong enough to absorb the expanding foam in its interior without bursting. In some embodiments, the envelope walls may be sized and shaped to produce a gap filling envelope of specific dimensions and/or shape. At the same time, the foaming composition is matched in type and quantity to the specific envelope and is self-contained within or adjacent the envelope for an integral package.
[0055] The envelope may be made of any of a variety of plastic polymers, such as polyethylene, polyester (e.g. Mylar), nylon or other polymeric material. In other embodiments, the envelope may contain intumescent materials to retard flame. In other embodiments, the envelope may be made of a bio-based material such as polylactic acid.
[0056]
[0057]
[0058] External to the envelope 116 at the mounting plate 128, plungers 138 extend into each syringe barrel 126, and terminate with a face 140 sealed against the inside of the syringe barrel with a suitable seal such as an O-ring 142. At the top, the plunger includes a pressure pad 144, or preferably a common pressure pad 144 links all plungers so they may be depressed simultaneously. To prevent premature activation during shipping and storage, a protective sheath 146 or cylindrical tube may be inserted between the underside of pressure pad 144 and the mounting plate 128 so that the plungers 138 cannot be inadvertently depressed until the protective sheath 146 is removed. Other embodiments of activation triggers 118 are described later, and would be equally suitable.
[0059] In use, the envelope 116 is installed in place in a large gap and optionally secured there using fastening straps 124. The protective sheath 146 is removed, and the plungers 138 are depressed into the syringe barrels 126, increasing the pressure until the release seals 132 rupture and the foaming compositions 130 begin to pass through the junction 134 and mix in the static mixer 136. As the components of the foaming composition mix, the foaming reaction is initiated and the foam begins to expand the envelope 116 to seal the large gap into which the envelope was installed.
[0060] Static mixers are well known in the industry and require little additional description. Many operate by the principles of flow division (repeated stream splitting) and/or radial mixing (rotational circulation). Others operate by principles of turbulence or tortuous path flow. All are designed to blend two or more separate fluid mixtures into a more homogeneous product. Some static mixers are linear or in-line (
[0061] Several typical installation methods are now described with reference to
[0062] As the foam expands, the envelope 116 unrolls and expands until the sides of the envelope begin to approach the joists 18, 38 on either side as well as the band joists 20, 40 on a third side. The envelope 116 expands up and down as well to occupy the large gap. As shown in
[0063] The shape and dimension of the integral seal 110 may be made specific for the site and installation method. For example, in the installation described above with respect to
[0064] For example, in
[0065] An external plunger has been described above as one means for triggering the foaming reaction. However, an activation trigger as used herein encompasses any mechanism that can be operated from outside the envelope to initiate a foaming reaction inside the envelope. Thus activation triggers may operate one or more of a wide variety of physical principles such as: (1) mechanical motion, such as pulling, pushing, or leverage; (2) pressure differentials, such as air pressure from compressed air, manual pressure, pinch rollers, etc; (3) invisible waves, such as sound waves (e.g. ultrasound); electromagnetic waves (light, IR, UV, X-ray, microwave, heat, etc); and (4) electrical stimulus, such a voltage potential, shock, etc.
[0066] An alternative activation trigger 218 is shown in
[0067] Prior to use and fusing the layers 219, the components of a foaming composition are sealed into the compartments 222. In use, pressure is applied to the flexible layers 219, such as for example by a pinch roller 240, to force the components of the foaming composition to rupture the release seals 232 (
[0068] The trigger 218 will be associated with an integral package envelope like 116 with at least the outlet 238 being sealed inside the envelope interior. Alternatively, the entire static mixer 236 or even the entire trigger assembly 218 may be within the envelope in some embodiments. It can still be activated from the exterior by applying sufficient pressure to the trigger. In such cases, it may be desirable to include delayed catalysts in the foaming composition so that the foaming reaction can be triggered on a bench prior to installation, and the delay allows sufficient time to install the envelope in the gap before the foaming reaction gets underway.
Other Embodiments and Variations
[0069] In general, the integral-type package 110 described above is particularly well suited for retrofit applications, although it may also be used in new construction. It is easy to use, even for the do-it-yourself population, since the prescribed quantity or dose of a foaming composition is self contained within or adjacent the envelope and can be activated from outside the envelope to initiate the foaming reaction. However, the additional costs associated with the triggering device make this a more expensive choice for the professional contractor doing bulk insulation, particularly in new construction where interjoist gaps and other gaps may be more accessible. For these users and applications, another package may be preferable, although either type package may be used in either application. An alternative embodiment comprises an envelope having, instead of a foam-filled activation device, a port or fitment through which bulk foaming composition may be delivered to the envelope interior. A delivery device for injecting bulk foaming composition is dimensioned to attach to the fitment port and to pump bulk foaming composition into the envelope. To distinguish this from the integral package embodiment, this embodiment is referred to herein as the fitment embodiment or bulk embodiment.
[0070] The bulk embodiment is described below in connection with
[0071]
[0072] Instead of an activation trigger, this embodiment is the bulk or fitment type and has a fitment port 317 on the exterior face of the envelope 316 which communicates to the interior. Fitment ports may vary, but a simple design consists of a hollow cylindrical piece of plastic or polymer with a flange that allows it to seal against the envelope (see also
[0073] When expanded, the envelope 316 includes tubular ribs 315 separated by the fused areas 322 as best seen in
[0074] In the simple fitment port 317 described above, the foaming compositionif a two-part compositionmust be mixed prior to entering the fitment port 317. This is also true of traditional two-part spray foams so existing delivery devices are generally capable of drawing up components from two sources, pumping them to a location, and mixing them in a delivery gun just before they are applied to a site. Such delivery guns are known in the art and are suitable for use to inject foaming compositions into envelopes with simple fitment ports like 317. The nozzle of the delivery device is generally cylindrical and can be inserted into the cylindrical fitment port. Adapters may be used if needed to ensure tight fits with no leakage of foaming composition. Simple friction fits are generally sufficient, although more complex bayonet mounts or screw mounts are possible and within the purview of the invention.
[0075]
[0076] The fibrous matrix may be made of polymer or inorganic fibers and may be bonded fibers or woven or non-woven fibers. It will be sized appropriately for the envelope size and quantity of foaming composition, to provide a mixing effect for foaming composition components that are injected through the fitment port into the matrix. Baffles or diverters (not shown) may be employed to direct foaming composition through a sufficient tortuous path of the fibrous matrix to effect the necessary mixing. In particular, an impervious barrier layer 424 of polyethylene or the like may be applied to the face of the fibrous matrix that is furthest from the front wall 416A. This helps control the flow path of the foaming composition to direct it perpendicular to the flow through the fitment wall 412, so that it flows through more of the matrix and improves mixing. Additionally, the matrix 422 provides some separation of the back wall 416B from the front wall 416A.
[0077]
[0078] This roll product is easily manufactured in long webs of intermittently fused layers, and rolled for shipping and storage. In use, one simply unrolls the web, separates an envelope along a perforation line, secures it to the desired substrate and connects a source of foaming composition to the fitment through a delivery device as described above. As with prior embodiments, the envelope 516 may be made in standard heights and width to fit conventional gap areas. Alternatively, by spacing the perforation lines 520 closer together (more frequently), the roll may be produced with fractional widths W3, such that multiple envelopes are used to fill a large volume. This modular approach offers more flexibility in filling gaps of varying sizes. In another variation, the roll may omit the perforation lines 520 and the user simple cuts the envelope to length along any fused area 522. Since the fused seam is no longer present, this variation produces an envelope that is open at the cut end along the top and bottom. This area may be fused manually, or it may be left open so that foam may extrude from this opening to further seal corner areas of a large gap and to further secure the envelope in position attached to the substrate such as a joist.
[0079] An alternative modular embodiment is illustrated in
[0080] In the specific embodiment illustrated in
[0081] Envelope segments 616 all include a fitment port 617 as was described previously for injecting a foaming composition to the interior of envelope. Since the volume of each segment is relatively small, it may be useful to provide a keying means to inform the delivery device how much volume to inject. RFID tags 630 can be used to convey this information to the delivery device.
[0082] In some embodiments, it may be desirable to provide strategic leak pores in the envelope. In
[0083] The choice of size of the segments is simply one of tradeoffs. The smaller the size of each segment, the greater the flexibility in shaping the envelope to fit an irregular volume. The concept is much that same as resolution of a monitorthe more pixels, the higher the resolution of the image. The tradeoff is that there are more ports to fill with even smaller quantities, thus contributing to labor costs. Balancing this tradeoff is within the purview of those skilled in the art to design reasonable flexibility with minimal labor time and expense. For typical interjoist gaps, the number of segments may range from 1 to about 24, more likely from about 1 to about 12 segments. However, the number is not critical and will certainly vary for other types of large volumes.
Foaming Compositions
[0084] The foams that may be used within the envelope may be of any of the known types of foaming compositions, including both open and closed cell foams. Generally speaking, foaming compositions include two reactive film-forming ingredients; a structure, scaffold or skeleton former; and a blowing agent. Other additives may be present of course as is taught in connection with known foaming compositions. The foams may be one-part, but reactive components must be kept separated until ready to initiate the foaming reaction. An easy way to keep the reactive components separated until desired is to package them in separate compartments or containers, which gives rise to description in the literature of two-part foaming compositions. Any of the one-part or two-part foams described in any of the following references, each of which is incorporated in its entirety by reference, can be used with the present invention. [0085] U.S. Pat. No. 5,444,099 to Abe et al., U.S. Pat. No. 4,945,120 to Kopp et al. and U.S. Pat. No. 3,984,360 to Galbreath et al. disclose polyurethane foams. [0086] U.S. Patent Publication Nos. 2008/0161430; 2008/0161431; 2008/0161433; 2008/0161432; 2009/0111902; and 2010/0175810 to Korwin-Edson et al. disclose latex foams. [0087] U.S. Patent Publication No. 2006/0047010 to O'Leary discloses a polyisocyanate prepolymer foaming composition. [0088] U.S. patent application Ser. No. 12/875,640, filed Sep. 3, 2010 and 61/421,680 filed Dec. 10, 2010 to O'Leary disclose non-aqueous based foaming compositions that will nevertheless foam at room temperatures.
[0089] The availability and low cost of isocyanate/polyol reagents that make low density polyurethane foams are well suited for use with the present invention. They are well tested and understood in the industry and make low density open cell foams in the 0.25 to 3 pound per cubic foot (pcf) range. While these foams have been avoided for spray applications, due to health concerns related to inhaling dangerous vapors, these dangers are removed or minimized in the present invention for two principle reasons. First, the foam is not sprayed or atomized so that it is more difficult to inhale. Even in the embodiment where a delivery gun or device is used, the foam is injected directly into the interior of the envelope and does not generally escape to the atmosphere. Second, the foam is largely self-contained within the envelope. Although some embodiments have strategic leak pores that allow some foam to escape, these are placed at the perimeters of the envelopes so that the foam has time to polymerize and set up before leaking to the exterior. In this way no toxic monomeric NCO's are likely to escape.
[0090] The foaming composition may contain other optional ingredients, in either or both of an A-side and B-side when two-part foams are used. Such optional ingredients may include catalysts, a nucleating agent, coagulation agents, foam promoters, opacifiers, accelerators, foam stabilizers, dyes (e.g., diazo or benzimidazolone family of organic dyes), color indicators, gelling agents, flame retardants, intumescents, biocides, fungicides, algaecides, fillers (aluminum tri-hydroxide (ATH)), and/or blowing agents. It is to be appreciated that a material will often serve more than one of the aforementioned functions, as may be evident to one skilled in the art. The additives are desirably chosen and used in a way such that the additives do not interfere with the mixing of the ingredients, the cure of the reactive mixture, the foaming of the composition, or the final properties of the foam. Other optional additives can be between 0 and 10% of the final formulation.
[0091] Some specific flame retardants include: Triethyl Phosphate TEP, Tributoxyl Ethyl Phospahte (TBEP), Tri-isobutyl Phosphate (TIBP), Tris (2-Chloroisopropyl) Phosphate (TCPP), Tris (1,3-dichloro-2-propyl) Phosphate (TDCP), Triphenyl Phosphate (TPP), Tricresyl Phosphate (TCP), Triphenyl Phosphite, Triphenyl Phosphine, Tris (2-chloroethyl) Phosphate (TCEP), 1-Phenyl-3-Methyl-5-Pyrazolone (PMP), AcetoacetanilideAAA, and Phosphate Flame Retardants BDP and RDP.
[0092] As mentioned earlier, for some embodiments it may be desirable to delay the onset of the foaming reaction once the trigger is activated. Some types of activation triggers may be used after the envelope is installed, while other types may be used on a bench or surface just prior to installation. In the latter case, delaying the onset of foaming to allow time to install the envelope may be desired. Certain modified catalysts can do this. Notably, to create a delayed action, formic acid can be added to either a gel catalyst such as TEDATriethylene amine or DBTDLDibutyltindilaurate; or to a blowing catalyst such as BDMAEEbis(2-dimethylaminoethyl ether) or DMDEE2,2 Dimorpholinodietyl ether.
[0093] In exemplary embodiments, the foams of the present invention, as well as the components thereof, meet certain performance properties, or Fitness for Use (FFU) criteria, both chemical and physical. In particular, desired criteria or FFUs that the inventive foam should meet are set forth in the table below:
TABLE-US-00002 Chemical Criteria Physical Criteria The foam should adhere to various The foam weight should be between about materials such as wood, metal, 0.2 and about 4.0 pounds per cubic foot concrete and plastic The foam should be fluid enough to be The chemical constituents should be sprayed either at room temperature or by safe. Even though isocyantates may heating (viscosity of <10,000 cP at a high be used, the dangerous monomeric shear rate) NCOs are not introduced or atomized The foam should not sag or fall in the cavity into the air where they can be inhaled; The foam should fill in cracks and crevices even if they extrude from the leak or be used to coat the cavity with an air pores, they are substantially barrier polymerized by then. Ideally, the cell structure of the foam (closed The foam may be chemically foamed vs. open) should be open cell structure to through the use of a blowing agent or provide appropriate material density it may be mechanically foamed with a properties and avoid volatile blowing agents gas The foam should have a thermal resistance The installer of the foam should be (R-value) of at least 3.0 Fft.sup.2h/BTU per inch able to work with the material without The foam should be non-sagging and non- any specialized personal protective dripping (i.e., fire retardant) during a fire equipment (PPE), such as a The foam should not corrode metal objects breathing apparatus, although such as screws, nails, electrical boxes, and chemical goggles, dust mask, and the like gloves are acceptable Air infiltration should be negligible (ASTM The foam should not lend itself to E283-04) (spec 0.4 cfm/sq ft) molding or fungus growth (ASTM Water vapor infiltration should be greater C1338) than 1 perm or 5.72 10.sup.8 g/Pa-s-m.sup.2 The foam should not contain a food The foam should have low or no odor. source for insects or rodents There should be a minimum shelf life of the un-reacted constituents of 9 months.
Methods and Process
[0094] The final foamed product becomes cured to the touch within minutes after application, and hardens within about 1 to 6 minutes. In foams intended for use as insulating materials, the resulting resistance to heat transfer, or R-value, is desirably from about 3.5 to about 8 per inch. In certain uses, the foamed product has an integral skin that restricts the passage of air but permits the passage of water vapor.
[0095] Another advantage of the foams of the present invention is the safe installation of the foam into cavities. Because the foams do not release any harmful vapors into the air when applied or sprayed, the inventive foams reduce the threat of harm to individuals working with or located near the foam. In addition, the application of the foams is more amenable to the installer as he/she will not need to wear a special breathing apparatus during installation.
[0096] Another advantage of the inventive foams is that it can be used in the renovation market, as well as in houses that are occupied by persons and/or animals (e.g. renovation market). Existing spray polyurethane foams cannot be used in these applications because of the generation of high amounts of free isocyanate monomers that could adversely affect the occupants of the dwelling. As discussed above, exposure of isocyanate monomers may cause irritation to the nose, throat, and lungs, difficulty in breathing, skin irritation and/or blistering, and a sensitization of the airways.
[0097] The invention of this application has been described above both generically and with regard to specific embodiments, although a wide variety of alternatives known to those of skill in the art can be selected within the generic disclosure. The invention is not otherwise limited, except for the recitation of the claims set forth below.