Patent Application
20080020206
It is well known how to make loose-fill clumps of inorganic fibers for forming blown-in insulation. The inorganic fiber used in the present invention can be glass fibers, mineral wool, slag wool, or a ceramic fiber and preferably is fiberglass, most preferably containing in the glass a boron oxide content of at least about 8 percent. Preferably the fiber has a mean or average fiber diameter less than or equal to about 3 microns such as an average fiber diameter of 2.5 microns or less, more preferably equal to or about 2 microns, even more preferably equal to or less than about 1.5 microns with the most preferred mean diameter being about 1 micron to produces an insulation product having high thermal performance at low installed densities.
Nodules are defined above as very small bundles of insulation fibers that are equal to or less than about one inch, more typically most of the nodules are not greater than about ½ inch in length, width and thickness or diameter and most typically almost all of the nodules are this latter size or smaller, i.e. at least about 90 percent of the nodules. Preferably, the size of at least the majority of the nodules in all three dimensions or diameter is ¼ inch or less. Clumps are defined as having a physical size greater than that of these nodules of fiber. Most conventional mineral fiber loose-fill insulation products designed for attic application consist of clumps of fibrous material. These types of products will not provide the desired uniformity and quality surface appearance required for spray-applied application to meet stringent inspection standards and to ensure consistent thermal performance. In addition, if these products were used for spray applied application, they would produce just installed insulation looking like that shown in
Referring to
Each blowing machine has an outlet through which the nodules of insulation are ejected as a rapidly moving air suspension. One end of a hose is connected to the outlet. The other end of the hose can be in the location that the operator will need for installing the insulation. The blowing machine hose can be up to about 200 feet long and can have a diameter of about 2.5 inches to about 4 inches or so, depending upon the type of blowing machine and the intended use or particular application. The blowing machine mixes the nodules with air and blows the resulting air suspension out the outlet and through the hose. A nozzle is normally attached to the end of the hose, the nozzle usually having one or more handles for the operator to hold to aim the nozzle in the proper direction and orientation for spraying the cavities. Nozzles are known as is shown in U.S. Pat. Nos. 5,641,368 and 5,921,055. The nozzle used in the present invention has preferably two or more jet spray tips for spraying the water or other liquid onto the nodules of fibrous insulation near the exit end of the nozzle, preferably at or past the exit end. Other non-aqueous liquids suitable for activating the adhesive or binder includes liquids that activate the adhesive, but that are not explosive or an environmental hazard.
An adjustable rate pump connected to a use tank of water or activating liquid, or directly to a water supply to provide water or other liquid at the proper rate and pressure to the jet spray tips through one or more flexible hoses to properly coat the nodules with the desired amount of water or other liquid. One or more jet spray tips can be used to apply the water or liquid to the nodules at an elevated pressure supplied by the pump. Usually two or three spray tips are used opposite each other across the moving column of suspended clumps and/or nodules. Many different types of jet spray tips can be used and one that performs well is Spray Systems Company's 25 degree flat spray Unijet® tip. Another jet spray tip that is suitable is Spray Systems Company's 65 degree Unijet® tip.
The resultant wet binder or adhesive coated clumps and/or nodules of mineral fiber insulation contain a moisture content of less than about 20-25 wt. percent, based on the dry weight of the clumps and/or nodules, preferably less than about 12 percent, more preferably less than about 10 wt. percent and can be down to less than about 7 weight percent or even lower depending on the type of building cavity or surface being insulated and depending on the nature of the binder or adhesive. At these weight percentages, the initial water content in a standard cavity would range from about 0.12 to about 0.35 lbs. for an R13 application for installed density ranging from about 0.8 to about 1.0 PCF.
Fibrous loose-fill insulation is subject to all three modes of heat transfer—radiation, conduction and convection. Convection can be minimized by reducing size of the nodules of loose insulation and preferably by producing more consistently sized nodules to limit potential air passages (voids) that can occur within the installed material. Convection is also minimized with a uniform cavity fill with no gaps or voids caused by bridging of the clumps, and with a fill that is such that the insulation is even with the framing faces when installation is complete. Small nodule size also makes this possible. If convection is kept to a minimum, infrared thermal radiation and conduction are the remaining modes of heat transfer that need to be reduced to ensure best thermal performance, i.e., high thermal resistance (R-value). Some studies have shown that if convection is minimized, infrared radiation can account for about 30 to 40% of the heat flow through a fibrous insulation product. The remaining portion of the heat flow would then be due to still air and solid material conduction. From a physics standpoint, a fibrous insulation product with fine fiber has more surface area per mass of fiberized material to intercept and scatter infrared thermal radiation versus a product with coarser fiber diameter. This is especially effective if the chemistry of the fiber enhances the scattering and absorption of the radiation. For glass fibers, having 8% or higher concentrations of B2O3 in the glass chemistry greatly enhances the scattering and absorption of infrared thermal radiation. Surface coatings can also be applied to fibers to enhance scattering and absorption. A network of fine fiber is also more effective in creating pockets of still air and minimizing sold conduction through the individual fibers. The combination of improved radiation scattering, minimal air movement and minimized sold conduction produces very good thermal performance. An additional benefit of fine fiber is that the material can be installed at low densities to achieve standard R-value requirements, e.g., R-13 @ 0.8 to 1.0 PCF installed density or R-15 @ 1.5 to 1.8 PCF in a standard 2×4, 8′ high, 16″ on center cavity.
The nodules of fibrous insulation for use in the present invention are made with conventional hammer mills, slicer-dicers or equivalent material processing machines. A slicer-dicer cuts or shears blankets, a layer, of fiberglass insulation into small cube-like or other three dimensional pieces. Hammer mills and the like tear and shear virgin fiber glass or fiber glass blanket and tend to roll them into generally irregular spherical or rounded nodules, keeping most pieces in the mill until they achieve a pre-selected size. The nodule size is controlled using an exit screen containing the appropriate opening size to produce the desired nodule size. Any type of fiberglass insulation product can be processed in a hammer mill, i.e. blanket in which the glass fibers are bonded together with a cured resin, usually a thermoset resin, or a blanket of virgin fiberglass containing only de-dusting oil, silicone anti-stat, etc. Also, the binder used to bond the glass fibers together in the blanket can also contain one or more of functional ingredients such as IR barrier agents, anti-static agents, anti-fungal agents, biocides, de-dusting agents, pigments colorants, microencapsulated phase change material (such as Micronal™ PCM from BASF), etc., or one or more of these functional ingredients can be applied to the fibers either before or during processing in the hammer mill or other reducing device.
The size of openings in an exit screen in the hammer mill or similar device are varied to produce the desired nodule size. The preferred size depends on the cutting and shearing characteristics of the fibrous material. For fiberglass material, an exit screen size with square openings ranging from 1 to 3 inches can be used to produce nodule or clump sizes that range in size from ⅛ inch to ¾ inch. The preferred screen size used to make the nodules making up the insulation product of the invention preferably has a continual pattern of 2 inch×2 inch squares or 2 inch diameter holes. This 2 inch screen opening size produces nodules of ¼ inch or smaller size range.
The nodules of inorganic fiber such as fiberglass can also be made from what is called “virgin blowing wool”. Virgin blowing wool is made by making glass fiber insulation in a conventional manner except that one or more dry, but water or liquid activatable, water based adhesive or hot melt adhesive is applied to the fibers. In addition, a de-dusting oil and/or an anti-stat like silicone is applied to the fibers and the resultant fibrous blanket is then run through the hammer mill or similar processing device. The water based or hot melt reactivatable adhesive and other agents can also be applied to the fibers such as a fungicide, a biocide, filler particles and/or IR retarding additives, either soon before or immediately before blowing through a nozzle or end of a hose, or earlier in the hammer mill or other nodulating machine. Although the activatable adhesive or binder can be dispersed throughout the nodules, it is desirable to have the adhesive or binder concentrated at the surface of the nodules.
The inorganic fibers used in the present invention can be glass, mineral wool, slag wool, or a ceramic fiber and preferably is fiberglass. Inorganic fibrous material has low moisture sorption (absorption and adsorption) potential, typically less the 5% moisture gain by weight. The application of fiber surface waterproofing agents, such as silicone or de-dusting oils can further reduce moisture sorption potential. A material with low moisture sorption is preferred for spray-applied application to allow for fast drying and to limit moisture storage capacity, which greatly limits the potential for mold growth.
The particles or nodules of the present invention are smaller and greater in number than used before as a blown in insulation product. Nodules are defined as very small diameter generally spherical, but having one or more radii, fibrous insulation of ¼ inch and smaller as described in the Summary. Having a small nodule size is important to achieve good installed thermal performance. With a small nodule size, the material will effectively fill around obstructions in building cavities such as electrical boxes, wiring and plumbing, thus, providing a uniform void-free fill. A small nodule size also allows the installer to maintain surface flatness and uniformity in the insulation product after excess material is removed from the cavity framing faces. Additional benefits from having small nodule size are reduced plugging potential as the material flows through the components of the blowing equipment, reduced potential for gaps and bridging voids along the framing members and elsewhere, more consistent R-values, improved air flow resistance and better wetting characteristics when adhesive is applied. The nodules of the present invention are smaller and greater in number than heretofore coated with water containing a water soluble adhesive and used to make a blown in insulation product.
In the invention the just installed insulation is obtained with nodules of insulation that are coated with a reactivatable, remoistenable adhesive. Production of the small coated nodules that make up the insulation product can be produced as shown in
Applying a reactivatable adhesive to the nodules 32 can be done by any of a number of alternative ways. If the reactivatable adhesive desired is available as a dry powder, the powder can be applied to the surfaces of the insulation nodules 32 by either blowing or mechanically slinging the powder onto the nodules 32 while they are falling through the air or are being tumbled or suspended in a mixer or insulation blowing machine. The dry powder particles attach to the surface portion of the nodules 32 by lodging in the openings between the fibers and by attaching to the fibers with static forces. Spraying the reactivatable adhesive in the form of a aqueous or solvent solution or suspension or a molten hot melt onto the nodules 32 as they fall past spray heads works better. When the reactivatable adhesive is water based it must be thoroughly dried before the coated insulation nodules are packaged to prevent their sticking together too tightly in the packages. This can be accomplished with a counter flow of hot air at a temperature sufficient to rapidly dry the coated nodules without deteriorating the adhesive. When the adhesive is applied as a molten hot melt, the coated nodules need to be cooled cooled sufficiently to solidify the adhesive before the nodules are collected together. The nodules 38 coated with a reactivatable adhesive can then go to a hopper above an insulating blowing machine or directly to the insulating blowing machine 2, or to packaging equipment 40.
There are many alternative ways to produce the reactivatable adhesive coated nodules. One alternative way is to feed, or dump bags or bales of compressed, loose-fill nodules of inorganic fiber loose-fill insulation made as described above into a hopper or mixer similar to conventional blowing machines. Reactivatable or remoistenable adhesives are sprayed or otherwise introduced into the hopper or mixer and the mixture is tumbled and then dried to produce fibrous nodules coated with the reactivatable adhesive. Spray applied reactivatable or remoistenable hot melt adhesives are desirable because there is no water to dry out—cool air sprayed onto the nodules will solidify the hot melt remoistenable adhesive very quickly leaving most of the adhesive on the outer surface of the nodules where it is most needed and where, upon remoistening, it produces the most tackiness for the nodules to stick together in the building cavity. Hot melt adhesive spray equipment is well known and readily available from a number of sources.
Reactivatable or remoistenable adhesives are typically applied to stamps, tapes, labels, envelopes, etc., during their manufacture to facilitate subsequent application and/or closure of those products. H.B. Fuller offers both water-based and hot melt remoistenable adhesives for a variety of application and performance requirements. Typical of some of the remoistenable hot melt adhesives are disclosed in U.S. Pat. No. 5,459,184, the disclosure of which is herein incorporated by reference. Specific product examples from other suppliers like DynaTech Adhesives include water based products like FlexTac™ 272 and 7465.
Hot melt remoistenable adhesives can be applied to the surfaces of the nodules in the form of particles, molten droplets or a molten fine fibrous web, the latter by using conventional hot melt spray nozzles and other spray, feeder, spreader or slining equipment. For example, hot melt remoistenable adhesives can be melted using a Nordson Series 3500 melt tank, the melted adhesive can then be pumped to a bank of Nordson Universal CF spray nozzles or other nozzles such as ITW Dynatec Laminated Plate Technology
Following drying and/or cooling, the nodules coated with a reactivatable, remoistenable adhesive are packaged in bags, barrels or boxes. The coated nodules need to be packaged such that the package prevents moisture or high humidity from penetrating the packaging material and activating the adhesive coating on the surface of the coated nodules that would cause the nodules to bond together forming one or more lumps of bonded together compressed nodules. Packaging materials, normally plastic, are well known for this purpose. The barrier material can be only a plastic bag or plastic drum, or a plastic bag inside another container such as Kraft boxes, bags or drums.
The resultant coated nodules of inorganic fiber insulation contain, also in an outer region of the nodules an amount of resin or adhesive content of less than about 10 wt. percent, based on the dry weight of the nodules, more typically less than about 4-5 wt. percent and most typically less than about 2 wt. percent for installed densities ranging from about 0.8 to about 2-3 PCF.
Some methods of making coated insulation nodules of the invention are illustrated in
The coated insulation nodules 55 continue to free fall through a chamber 56 where they encounter a counter flow of hot, drying air, or when the reactivatable adhesive is a molten hot melt, cooling air, supplied by a manifold 59 surrounding the chamber 56 and communicating with the interior of the chamber 56 via a continuous or interrupted circumferential slot or a plurality of spaced apart hollow conduits. A stream of hot or cool air 60 is supplied to the manifold 59 in known manner. The resultant hot, or cool, reactivatable adhesive coated insulation nodules 62 of the invention continue to fall into a collection chamber 64. When the coated nodules 62 are hot, they can optionally be cooled by a flow of cool air 66 via a manifold 65 surrounding a lower portion the collection chamber 64. One or more agitator/feeders 67 in the bottom of the collection chamber 64 feed the coated nodules 62 at a desired rate into either conventional packaging equipment (not shown) to produce sealed packages 68 of compressed, coated nodules 62 of the invention, or into an insulation blowing machine.
As shown in
Virgin glass fiber having an average fiber diameter of 2 microns and made by a conventional process such as described in U.S. Pat. No. 4,058,386, is fed to a hammer mill containing an exit screen having hole diameters sized to produce nodules of one half inch and smaller diameters. These nodules are allowed to fall in front of a bank of hot melt adhesive spray heads spraying H.B. Fuller Co.'s NP 2255 remoistenable hot melt adhesive to coat the nodules. The remoistenable hot melt is applied to the falling nodules in a process like that illustrated in
A moisture activated envelope flap type adhesive such as Dyna-Tech™ Flextac™ 272 or 7465 is spray applied to fiberglass nodules like those described in Example 1. These adhesives are water based and are pumped to spray jets with a pump as shown in
As shown in
A Unisul Volumatic® III insulation blowing machine equipped with 150 feet of 4 inch diameter hose is used to produce an insulation mass flow rate of approximately 18 lbs/minute of the reactivatable adhesive coated insulation nodules of Examples 1, 2, and 3, each comprising glass fibers having an average fiber diameter of 2 microns and an average nodule diameter in the range of about 0.25 to about 0.6 inch. The glass fiber in the nodules contains an average boron oxide content of about 8.7 wt. percent.
The blowing machine is operated with the transmission in 3rd gear, with 100% of the available blower air delivered to the rotary airlock assembly and with the slide gate (feed gate) set at 12 inches. The blower and secondary gearbox speeds (RPM settings) on the blowing machine are set to the manufacturer's recommended settings of 1425 and 1050 rpm, respectively. The mass flow of insulation is allowed to freely flow through the blowing hose into a nozzle at the end of the blowing hose. Spray jets on the outside of the nozzle are used to spray water to the mass flow of coated nodule insulation as the coated nodules exit from the nozzle. The water is applied at a rate of about 0.25 gallons/minute with the use of a Spray Tech pump (model 0295003). The spray nozzle assembly consists of a 4 inch diameter tube, the end of which is surrounded by an annular manifold containing two Spray System Co. model TPU-65-015 spray tips screwed into threaded ports located 180 degrees apart on the manifold. The ports are set at a 30 degree angle to the centerline of the mass insulation flow direction. This allows the water to be sprayed and entrained into the mass flow of coated nodules without disrupting the flow characteristics of the nodules to provide an insulation to water ratio in the just installed product of about 9:1.
By moving the nozzle from bottom to top and with a side to side motion from the bottom of the cavity to the top, the wetted, activated coated nodules of insulation is directed into various 8 foot high cavities defined between 8 foot high vertical 2×4's or 2×6's spaced on 16 inch centers or 24 inch centers to achieve a consistent fill with about 2-3 inches of excess insulation material extending beyond faces of each vertical framing member. Standard SPF wood framing (2×4 or 2×6) is used to form the cavities of the test walls. Oriented Strand Board (OSB) sheathing is used as the back wall of each cavity. The spray nozzle is held approximately 6 feet away from the open cavity during the installation process. Shortly after installation, the excess material is removed with the use of a commercial rotary wall scrubber (Krendl™ model 349B). The removed excess material is vacuumed up using a 50 foot length of 4 inch diameter hose connected to a centrifugal vacuum fan (Wm. W. Meyer & Sons, Inc. Versa-Vac (11) for recycling. At this flow rate, installation times of about 10 to about 15 seconds are required to fill a standard cavity. This is a much shorter application time than heretofore possible with prior art products.
Using the described equipment set up, the just installed moisture content of the insulation in each test wall is about 10-15 wt.% on an oven dry mass basis. Measurement is accomplished with the use of a load cell connected to a chain hoist. A large oven is used to dry the samples after the initial weights are taken. Over the 10-15% range, approximately 0.25 to 0.35 lbs of water exists in a standard 8 foot high, 16 inch on center 2×4 wall cavity. The oven dry density of the installed material is in the range from 0.9 to 1.1 PCF. Thermal testing on various samples in this same density range shows that the material provides an R-13 level of insulation in a standard 2×4 cavity. Loss On Ignition (LOI) testing indicates that approximately 2 to 3% adhesive solids exists in the installed material. With this content of adhesive solids, no problems are encountered with any installed material falling out of the wall cavities or with any post-installation settling or fallout in both 2×4 and 2×6 cavities. As the installed insulation dries, the adhesive provides still further bond strength and integrity in the insulation. The present invention, in applications at the lowest densities disclosed, will exhibit sufficient integrity to resist settling, shrinkage, or collapse in the cavity, even at a depth of 6 inches or more.
At a distance 6 foot from the cavity face densities in a range from 0.8 to 1.2 PCF can be consistently obtained. At 4 feet away, densities ranging from 1.3 to 1.5 PCF can be obtained and at 2 feet away, densities ranging from 1.6 to 1.9 PCF are achieveable. This ability to vary the installed density allows respective R-values of R-13, R-14 and R-15 to be obtained in standard 2×4 cavities. The results of this Example are found in Tables 1 and 2 below.
In addition to the equipment set up previously described, numerous other combinations of pump flow rates, adhesive to water ratios, spray nozzle configurations, blowing machine settings, blowing machine types, adhesives and installation techniques can be used to achieve similar installed densities and similar or lower moisture levels. The particular settings described above primarily resulted from conducting a series of designed experiments to identify optimal settings that would deliver desired installation and performance characteristics of insulation material similar to that disclosed herein. The above results are demonstrative of the very low installed density, the very low installed cavity moisture weight and the very fast installation that is achievable with the present invention in comparison to the prior art. Installed moisture levels as low as about 2% can be obtained, but at some expense of other desired characteristics such as installation time and/or adhesive cost.
When filling wall cavities with sprayed-on insulation it is necessary to spray an excess of insulation nodules to make sure each cavity is fully filled. This requires that the excess insulation be either removed, or compressed to be even with the face of the studs after spraying and before the adhesive coating on the clumps or nodules dries to enable wall board, or other facing board to lie flush on the faces of the studs. As confirmed in U.S. Pat. No. 5,641,368, it has been found that a powered scrubber conventionally used to remove excess thickness of sprayed insulation will not work with conventional sprayed-on loose-fill fiberglass insulation because the powered reverse rotating action of the scrubber often tears large chunks of the fiberglass from the cavity. A scrubber is a rotating brush-like device that is long enough to span two adjacent studs. Although called a scrubber, water or other liquid is not involved in its use.
The use of a scrubber with the product of the present invention would not result in the reported problem. Because of the higher tackiness and small size of the nodules that form the insulation product of this invention, and the absence of voids caused by bridging, a scrubber is perfectly acceptable for removing excess insulation. Scrubbers do not tend to tear out large chunks from the insulation between the studs. It is not necessary to roll the just installed insulation of the present invention to reduce the thickness to the desired amount and preferably it is not rolled or compressed by any other means. These same features minimize slumping and collapse of the insulation during formation. Preferably, any excess thickness is removed using a scrubber or other functionally equivalent means.
As confirmed in the just above mentioned patent and others, it has been found in the past that excess adhesive was required to coat clumps of fiberglass containing a silicone, but an additional aspect of the present invention is that the clumps and/or nodules of insulation can contain silicone which is desirable for the waterproofing function that the silicone conventionally produces.
Biocide and/or desiccant agents can be added to the material during manufacturing or during installation to provide additional protection against potential mold growth and to potentially protect adjacent substrate materials (framing, sheathing, etc.) from potential mold growth.
With some or all of these unique attributes, a uniform cavity fill can be obtained over a wide range of installed R-values at low installed densities, having low moisture contents for fast drying. Mold growth potential is minimized by keeping the installed density low and the material cost is kept to a minimum.
Several examples and ranges of parameters of preferred embodiments of the present invention are described above, but it will be apparent to those of ordinary skill in the insulation field that many other embodiments may be possible by manipulation of the parameters of the invention. For example, although only a few different reactivatable adhesives are specifically disclosed, there are other suitable adhesives that will function in the same or very similar manner as in the above disclosed invention to produce the useful result of having high tack value. While most of the above discussion involves using the present invention in generally vertical wall cavities, this insulation product can also be used to insulate attics, ceilings, undersides or sloping roofs or any area that can be reached with a spray of the activated, air suspended nodule product.
