U.S. patent application number 10/916326 was filed with the patent office on 2005-02-10 for duct board with low weight water repellant mat.
Invention is credited to Mankell, Kurt O., Mattix, Greg, Ruid, John O., Toas, Murray S., Tomchak, David.
Application Number | 20050031819 10/916326 |
Document ID | / |
Family ID | 32711821 |
Filed Date | 2005-02-10 |
United States Patent
Application |
20050031819 |
Kind Code |
A1 |
Mankell, Kurt O. ; et
al. |
February 10, 2005 |
Duct board with low weight water repellant mat
Abstract
A duct board or duct liner product is provided comprising an
insulating layer formed from fibrous material bound with a resin
binder; an outer facing layer adhered to an outer surface of the
insulating layer; and a water repellant mat facing adhered to an
interior surface of the insulating layer opposite the outer surface
to form a duct board material, the mat facing having a weight of
less than 1.1 lb/100 ft.sup.2 (53.6 g/m.sup.2) and having at least
an INDA 2 water repellence rating using the IST 80.6-92 water
repellency test method.
Inventors: |
Mankell, Kurt O.; (Blue
Bell, PA) ; Toas, Murray S.; (Norristown, PA)
; Mattix, Greg; (Collegeville, PA) ; Ruid, John
O.; (Schwenksville, PA) ; Tomchak, David;
(Westfield, IN) |
Correspondence
Address: |
DUANE MORRIS, LLP
IP DEPARTMENT
ONE LIBERTY PLACE
PHILADELPHIA
PA
19103-7396
US
|
Family ID: |
32711821 |
Appl. No.: |
10/916326 |
Filed: |
August 11, 2004 |
Related U.S. Patent Documents
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Application
Number |
Filing Date |
Patent Number |
|
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10916326 |
Aug 11, 2004 |
|
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10342849 |
Jan 14, 2003 |
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Current U.S.
Class: |
428/36.91 ;
138/149 |
Current CPC
Class: |
Y10T 442/2189 20150401;
Y10T 428/1317 20150115; Y10T 428/1362 20150115; Y10T 428/1393
20150115; Y10T 428/1314 20150115; B32B 5/26 20130101; F24F 13/0263
20130101; F24F 13/0281 20130101; Y10S 138/04 20130101; Y10T
428/1321 20150115; Y10T 428/131 20150115; Y10T 428/1352 20150115;
Y10T 428/139 20150115; Y10T 442/2164 20150401 |
Class at
Publication: |
428/036.91 ;
138/149 |
International
Class: |
B29D 022/00 |
Claims
What is claimed is:
1. A duct board or duct liner product, comprising: an insulating
layer formed from fibrous material bound with a resin binder; an
outer facing layer adhered to an outer surface of the insulating
layer; and a water repellant mat facing adhered to an interior
surface of the insulating layer opposite the outer surface to form
a duct board material, the mat facing having a weight of less than
1.1 lb/100 ft.sup.2 (53.6 g/m.sup.2) and having at least an INDA 2
water repellence rating using the IST 80.6-92 water repellency test
method.
2. The duct board or duct liner of claim 1, wherein the weight of
said mat facing is less than about 1.0 lb/100 ft.sup.2 (48.73
g/m.sup.2).
3. The duct board or duct liner of claim 1, wherein the weight of
said mat facing is between about 0.80 lb/100 ft.sup.2 (39.0
g/m.sup.2) and 0.97 lb/100 ft.sup.2 (47.5 g/m.sup.2).
4. The duct board or duct liner of claim 1, wherein the mat facing
is formed from a non-woven fiber material having a water repellent
material integral therein.
5. The duct board or duct liner of claim 4, wherein the mat facing
comprises non-woven glass fibers bound with a resin.
6. The duct or duct liner of claim 1, wherein the mat facing is
adhered to a surface of said insulating layer by an adhesive, said
adhesive and insulating layer being substantially free of water
repellent additives or agents.
7. The duct board or duct liner of claim 1, wherein the mat facing
comprises a non-woven fiberglass and water repellant material
comprising a fluorinated polymer, said mat facing having a weight
between about 0.80 lb/100 ft.sup.2 (39.0 g/m.sup.2) and 0.97 lb/100
ft.sup.2 (47.5 g/m.sup.2).
8. The duct board or duct liner of claim 1, wherein the resin
binder in at least a portion of said insulating layer is formed
from a resin in an aqueous carrier mixed with a hydrophobic agent
in emulsion form.
9. The duct board or duct liner of claim 8 wherein the hydrophobic
agent is present in said binder in a ratio of about 1:200 to 1:5
hydrophobic agent to binder.
10. The duct board or duct liner of claim 9, wherein said
hydrophobic agent is selected from the group consisting of
emulsions, latexes, silicone, oil, fluorocarbon and waxes.
11. The duct board or duct liner of claim 1, wherein: the mat is
adhered to a surface of said insulating layer by an adhesive
containing a first hydrophobic agent, and the resin binder in at
least a portion of said insulating layer contains a second
hydrophobic agent.
12. The duct board or duct liner of claim 11, wherein the first
hydrophobic agent is one of the group consisting of emulsions,
latexes, silicone, oil, fluorocarbon and waxes.
13. The duct board or duct liner of claim 11, wherein the resin
binder in the portion of said insulating layer is formed from a
resin in an aqueous carrier mixed with a hydrophobic agent in
emulsion form.
14. The duct board or duct liner product according to claim 1,
wherein the duct board material is formed in a tubular shape
capable of conducting air, with the mat facing on an interior
thereof.
15. A method for forming a duct board or duct liner product,
comprising: (a) adhering an outer facing layer to an outer surface
of an insulating layer formed from fibrous material bound with a
resin binder; and (b) adhering a water repellant mat facing to an
interior surface of the insulating layer opposite the outer surface
to form a duct board material, the mat facing having a weight of
less than 1.1 lb/100 ft.sup.2 (53.6 g/m.sup.2) and having at least
an INDA 2 water repellence rating using the IST 80.6-92 water
repellency test method.
16. The method of claim 15, further comprising forming the duct
board material into a tubular shape capable of conducting air, with
the mat facing on an interior thereof.
17. The method of claim 15, wherein the weight of the mat facing is
less than about 1.0 lb/100 ft.sup.2 (48.73 g/m.sup.2).
18. The method of claim 15, wherein the weight of the mat facing is
between about 0.80 lb/100 ft.sup.2 (39.0 g/m.sup.2) and 0.97 lb/100
ft.sup.2 (47.5 g/m.sup.2).
19. The method of claim 18, wherein the mat facing is formed from a
non-woven fiber material having a water repellent material integral
therein.
20. The method of claim 19, wherein the mat facing comprises glass
fibers bound with a resin.
21. The method of claim 20, wherein the mat facing is adhered to a
surface of said insulating layer by an adhesive, said adhesive and
insulating layer being substantially free of water repellent
additives or agents.
22. The method of claim 15, wherein the mat facing comprises a
non-woven fiberglass and water repellant material comprising a
fluorinated polymer, said mat facing having a weight between about
0.80 lb/100 ft.sup.2 (39.0 g/m.sup.2) and 0.97 lb/100 ft.sup.2
(47.544.2 g/m.sup.2).
23. A duct board or duct liner product, comprising: an insulating
layer formed from fibrous material bound with a resin binder; an
outer facing layer adhered to an outer surface of the insulating
layer; and a non-woven glass fiber mat facing adhered to an
interior surface of the insulating layer opposite the outer surface
to form a duct board material, said mat facing having a water
repellent material integral therein, the mat facing having a weight
of between about 0.80 lb/100 ft.sup.2 (39.0 g/m.sup.2) and 0.97
lb/100 ft.sup.2 (47.5 g/m.sup.2) and having at least an INDA 2
water repellence rating using the IST 80.6-92 water repellency test
method, wherein the mat is adhered to a surface of said insulating
layer by an adhesive, said adhesive and insulating layer being
substantially free of water repellent additives or agents.
24. The duct board or duct liner product according to claim 23,
wherein the duct board material is formed in a tubular shape
capable of conducting air, with the mat facing on an interior
thereof.
25. The duct board or duct liner product according to claim 23,
wherein said water repellent material comprises a fluorinated
polymer.
Description
CROSS REFERENCE TO RELATED APPLICATIONS
[0001] This application is a continuation-in-part of U.S. patent
application Ser. No. 10/342,849, entitled "Duct Board With Water
Repellant Mat" filed Jan. 14, 2003, the entirety of which is hereby
incorporated by reference herein in its entirety.
[0002] This application is related to U.S. patent application Ser.
No. 10/141,595, entitled "Duct Board Having Two Facings" filed May
8, 2002, the entirety of which is hereby incorporated by reference
herein in its entirety.
FIELD OF THE INVENTION
[0003] The present invention relates to building products in
general and, in particular, to duct board and duct liner materials
and ducts made therefrom.
BACKGROUND
[0004] Ducts and conduits are used to convey air in building
heating, ventilation and air conditioning (HVAC) systems. In many
applications, especially in commercial and industrial construction,
the ducts are lined with flexible thermal and sound insulating
material. The lining enhances the thermal efficiency of the duct
work and reduces noise associated with movement of air
therethrough. Duct liner may comprise any suitable organic material
or inorganic material, e.g., mineral fibers such as fiber glass
insulation or the like. Typical fiber glass duct liners, for
example, are constructed as fiber glass mats having densities of
about 1.5 to 3 pounds per cubic foot (pcf) and thicknesses of about
0.5 to 2 inches. To prevent fiber erosion due to air flow, the
insulation may include a coating of on its inner or "air stream"
surface. The air stream surface of the insulation is the surface
that conveys air through the duct and is opposite the surface that
contacts the duct sheet metal in the final duct assembly. The
coating also serves to protect the insulation during brush and/or
vacuum cleaning of the interior of the duct. Examples of duct
liners having coatings on their inner surfaces are provided in U.S.
Pat. Nos. 3,861,425 and 4,101,700. Several coated insulation duct
liners or boards are marketed under the trade designations
Toughgard.RTM. and Ultra*Duct.TM. Gold by CertainTeed Corp. of
Valley Forge, Pa., Aeroflex.RTM. and Aeromat.RTM. by Owens Corning
Fiberglas Corp. of Toledo, Ohio, Permacote.RTM., Polycoustic.TM. by
Johns Manville Corp. of Denver, Colo. and Knauf Airduct Board-M by
Knauf Insulation of Shellbyville, Id.
[0005] Other insulated HVAC systems use ducts either fabricated
from or lined with rigid duct boards or tubes. Duct boards are
rigid members formed from resin-bonded mineral fibers and whose air
stream surfaces may also be provided with protective coatings. Duct
boards typically have densities of about 3 to 6 pounds per cubic
foot (pcf) and thicknesses of between about 0.5 to 2 inches. Coated
and uncoated duct boards are marketed under a variety of trade
designations from the aforementioned manufacturers of duct liners.
Whether provided on duct liners or duct boards, dedicated
water-resistant coatings add to the cost and complexity of
manufacturing these products.
[0006] It is well known that microorganisms will grow in an
environment where moisture and nutrients are present and that many
species of microorganisms have a negative impact on indoor air
quality (IAQ). If liquid water leaks into air duct insulation, the
water may collect and stagnate in the insulation and support the
growth of microorganisms.
[0007] To address the problem of microorganism growth in HVAC
systems, U.S. Pat. Nos. 5,314,719; 5,379,806; 5,487,412 and
5,783,268 disclose providing antimicrobial agents on or in the
air-conveying surfaces of impermeable duct liners and/or duct
boards. However, these antimicrobial agents have very limited zones
of effectiveness. That is, they tend to prevent microbe formation
only in their immediate vicinity. U.S. Pat. No. 5,314,719, for
example, describes a zone of antifungal inhibition of about one
millimeter. Typical duct liners and duct boards have insulation
thicknesses ranging from about one-half to two inches. In these
products, such a limited zone of inhibition would be essentially
useless in preventing microorganism formation caused by duct
insulation that becomes saturated by water entering through the
exterior walls and seams of the duct.
[0008] Moisture impermeable coatings, if applied to the airstream
surface of air duct insulation products, inhibit ingress of water
into the insulation and attendant microorganism formation therein.
U.S. Pat. No. 3,861,425 discusses providing HVAC ducts either
composed of or lined with fibrous glass insulation media such as
batts, mats, boards or the like with such coatings. While certain
coatings may provide the benefits of fiber erosion protection and
moisture resistance, they add to the cost and complexity of the
products and their methods of manufacture. Coatings applied to the
air stream surface of fibrous insulation products are applied to
those products after their formation. This requires application of
the coating to the previously formed insulation product by brush,
roller, sprayer or by some other means or method and thereafter
allowing the coating to cure or dry. This post-formation coating
step may prolong the time required to manufacture the insulation
product and, whether performed manually or automatically, must be
carefully monitored in order to assure uniformity in application of
the coating.
[0009] As an alternative to coated duct liners and duct boards, at
least CertainTeed Corp. and Knauf Fiber Glass GmbH offer duct
liners or duct boards having glass fiber insulation covered with a
layer of non-woven facing material which defines the air stream
surface of those products. The facing material produces a durable
surface that protects the air duct from fiber erosion.
[0010] However, both uncoated fibrous insulation HVAC duct products
and some products that are covered with facing material possess
limited inherent moisture resistance. Consequently, they are
susceptible to microorganism formation in the event they become
wet.
[0011] Further, the coating selected for these coated duct liners
and duct boards can significantly add to the products cost.
SUMMARY OF THE INVENTION
[0012] A duct board or duct liner product and method of making the
same is provided. The duct board or duct liner product comprises an
insulating layer formed from fibrous material bound with a resin
binder; an outer facing layer adhered to an outer surface of the
insulating layer; and a water repellant mat facing adhered to an
interior surface of the insulating layer opposite the outer surface
to form a duct board material, the mat facing having a weight of
less than 1.1 lb/100 ft.sup.2 (53.6 g/m.sup.2) and having at least
an INDA 2 water repellence rating using the IST 80.6-92 water
repellency test method.
[0013] By limiting the weight of the nonwoven facing, significant
cost savings can be realized while providing a cost effective,
abuse resistant water repellant airstream surface for the mineral
fiber duct product. Additional cost savings can be realized in
embodiments where no additional water repellent is added to the
binder of the duct board or adhesive used to adhere the nonwoven to
the duct board.
[0014] In one embodiment, the mat facing has a water repellent
material integral therein and the mat facing has a weight of
between about 0.80 lb/100 ft.sup.2 (39.0 g/m.sup.2) and 0.91 lb/100
ft.sup.2 (44.2 g/m.sup.2). The mat is adhered to a surface of said
insulating layer by an adhesive, and the adhesive and insulating
layer are substantially free of water repellent additives or
agents.
BRIEF DESCRIPTION OF THE DRAWINGS
[0015] FIG. 1 is a cross sectional view of a duct board material
according to one embodiment.
[0016] FIG. 2 is a diagram of apparatus for forming the insulation
layer of the material shown in FIG. 1.
[0017] FIG. 3 is a diagram of apparatus for applying the mat facing
to the duct board material shown in FIG. 1.
[0018] FIG. 4 is an isometric view of the duct board of FIG. 1,
after it is folded into an air duct.
DETAILED DESCRIPTION
[0019] Application Ser. No. 09/789,063, filed Feb. 20, 2001, and
application Ser. No. 09/788,760, filed Feb. 20, 2001 are
incorporated by reference herein in their entireties.
[0020] This description of the exemplary embodiments is intended to
be read in connection with the accompanying drawings, which are to
be considered part of the entire written description. In the
description, relative terms such as "lower," "upper," "horizontal,"
"vertical,", "above," "below," "up," "down," "top" and "bottom" as
well as derivative thereof (e.g., "horizontally," "downwardly,"
"upwardly,"etc.) should be construed to refer to the orientation as
then described or as shown in the drawing under discussion. These
relative terms are for convenience of description and do not
require that the apparatus be constructed or operated in a
particular orientation. Terms concerning attachments, coupling and
the like, such as "connected" and "interconnected," refer to a
relationship wherein structures are secured or attached to one
another either directly or indirectly through intervening
structures, as well as both movable or rigid attachments or
relationships, unless expressly described otherwise.
[0021] FIG. 1 is a cutaway view of a portion of a duct board or
duct liner material 10. A duct board or duct liner 10 comprises an
insulating layer 12, 13 formed from fibrous material bound with a
resin binder, an outer facing layer 18 adhered to an outer surface
of the outer insulating layer portion 13 and a water repellant mat
facing 14 adhered to an interior surface of the inner insulating
layer portion 12 opposite the outer facing layer 18 to form a duct
board or duct liner material. The mat facing 14 provides sufficient
water repellency to repel a mixture of about 40% isopropanol and
about 60% water under IST Test No 80.6-92. The mat facing 14 may
optionally provide sufficient water repellency to repel a mixture
of greater than 40% isopropanol. The duct board or duct liner
material 10 is formed into a tubular shape capable of conducting
air, with the mat facing 14 on an interior thereof. FIG. 4 shows an
exemplary air duct formed from the duct board 10. A duct liner
would have a similar appearance, but would have a lower density
suitable for placement inside a duct. Although a rectangular duct
is shown the duct may be formed into a non-rectangular tubular
shape, such as round or oval, as is known in the art.
[0022] The mat facing 14 may be formed from a woven or non-woven
fiber material. The material may be inherently water repellant, or
it may be treated with a water repellant material that includes a
treatment such as wax-asphalt emulsion, silicone or fluorocarbon,
for example, to provide the desired water repellency.
[0023] A preferred mat material 14 has a water repellency
sufficient to repel a drop including at least 80% isopropyl alcohol
and water for a minimum of five minutes, using an IST 80.6-92 test
method. Materials that repel up to 100% isopropyl alcohol in an IST
80.6-92 test may be used. In some preferred embodiments, the mat 14
is formed from water repellant 40# Manniglass 1886 Black mat or
1786 Black mat from Lydall Inc. of Green Island, N.Y. or water
repellant Elasti-Glass.RTM. 3220B mat from Johns Manville of
Denver, Colo.
[0024] In other embodiments, the mat 14 is formed from filament
glass fibers in an acrylic-based binder, such as Johns Manville
Dura-Glass.RTM. 8440 with a water repellant (e.g., silicone or
fluorocarbon) applied thereto.
[0025] Other mat materials providing similar or better degrees of
water repellency may alternatively be used. For example, such
materials may include non-woven mats of glass fibers randomly
dispersed into a web in a wet-laid process, bound in an acrylic or
other resin system, and post treated with a fluorocarbon based
coating that provides the desired degree of water repellency.
[0026] Product 10 comprises an insulating layer 12, 13 of mineral
fibers such as glass fibers, refractory fibers or mineral wool
fibers bonded by a suitable resin and mat facing 14 of adhered
thereto by adhesive 16, wherein the facing material 14 defines the
air stream surface for the board or tube. Binders that may be used
to bind the fibers of insulating layer 12, 13 may include, without
limitation, the phenolic binders disclosed in U.S. Pat. Nos.
5,300,562 and 5,473,012, the disclosure of which are incorporated
herein by reference. Product 10 may have a density of about 0.5 to
6 pounds per cubic foot (pcf) and a thickness of between about 1.27
to 5.08 centimeters (0.5 to 2 inches). The thickness and density of
insulation layer 12, 13 is dictated by whether the product is a
duct board or duct liner, and is also influenced by the levels of
acoustic and/or thermal insulation that are desired or necessary
for a particular building installation. One of ordinary skill in
the art understands that other known duct board fabrication
processes may be used.
[0027] Although the piece of duct board material shown in FIG. 1
has a female shiplap edge and a male shiplap edge with a strip of
the outer facing layer 18 overhanging the male shiplap edge, other
configurations are formed with or without shiplap edges.
[0028] In some embodiments, the water repellant mat facing 14 alone
provides the desired degree of water repellency. In other
embodiments, as described below, the water repellency of the
product 10 is enhanced by an additive in either the binder of the
insulation layer 12, 13, the adhesive joining the facing 14 to the
insulation 12, or both.
[0029] As will be appreciated by reference to FIG. 1, the
insulation layer 12, 13 is formed as a series of accumulated layers
of resin-bonded fibers which, in the end product, may be
intertwined and appear and exist as a continuous homogeneous mass
rather than as a plurality of distinct or discrete strata or
lamina. For simplicity of illustration and explanation, product 10
is referred to below as comprising first and second portions 12 and
13, although typical rigid duct boards and tubes include many bound
layers. The location of the dashed line between portions 12 and 13
is optional. In some embodiments, portions 12 and 13 are continuous
and of identical composition, and may be considered a single layer.
In other embodiments, as described below, portion 12 has an
additive not contained in portion 13, portion 13 has an additive
not contained in portion 12, or portion 12 and 13 contain different
additives. In some embodiments, portion 12 is thicker. In other
embodiments, portion 13 is thicker.
[0030] In some embodiments, the water repellency of the duct board
or tube is optionally enhanced by incorporating a hydrophobic agent
into the binder of at least one of the portions 12, 13. In one
example, the hydrophobic agent is incorporated into portion 12
which is closer to the air stream surface of product 10, and
adjacent to the facing 14; portion 13 does not, therefore, have to
have the hydrophobic agent in the binder thereof, but may. In this
way, liquid water or other aqueous liquids from the interior of the
duct which penetrates facing 14 is further repelled from entering
product 10, thereby reducing the likelihood of microbial growth in
the insulation. Preferably, a foil/scrim/paper laminate or other
suitable vapor retarder layer 18 is adhered or otherwise affixed to
the face of product opposite the air stream surface of layer 12 to
prevent moisture from entering the insulation from the ambient
environment.
[0031] FIG. 2 shows a forming section for forming the insulating
layer 12, 13 which includes the optional hydrophobic agent in the
binder of portion 12. Insulation layers 12 and 13 may be made in
forming section 19 by melt spinning molten material, such as glass,
into veils 20 of fine fibers using a plurality of fiberizing units
22a-22f. The veils of fibers enter a forming hood 24 where a
binder, such as a phenolic resin, in an aqueous carrier (or water
and binder in sequence) is sprayed onto the veils 20. In the
forming hood 24, fibers are accumulated and collected as a web on a
chain, belt or other conventionally-driven conveyor 26. In order to
impart hydrophobicity to portion 12, at least fiberizing unit 22f
is configured to dispense binder having a hydrophobic agent
incorporated therein. After the web exits the forming section 19,
it is conveyed to an unillustrated conventional curing oven for
compressing and curing the web to a desired thickness and
density.
[0032] While in the oven, portions 12, 13 are simultaneously heated
in order to cure the binder and adhere the portions to one another
so as to form the homogeneous mass of product 10. Preferably, the
multiplicity of layers of fibers are held together by unillustrated
heated platens or the like under sufficient pressure to compress
the mass of fibers in portions 12 and 13 against each other. After
product 10 exits the curing oven, vapor retarder layer 18 is
applied to the surface of layer 13 opposite the air steam
surface.
[0033] In some embodiments, the binder used in at least portion 12
includes at least one hydrophobic agent such as silicone, oil,
fluorocarbon, waxes, wax-asphalt emulsions, acrylics, other
emulsions, latexes, polyvinyl acetates, etc. or the like in an
effective amount sufficient to render the product water repellent
and resistant to aqueous solutions containing moderate quantities
of solvent regardless of the water repellency of the airstream
facing layer 14. Depending upon the hydrophobic agent selected,
effective amounts of hydrophobic agent may range in a ratio of
about 1:200 to 1:5 hydrophobic agent to binder. In one embodiment,
a commercially available hydrophobic agent suitable for these
purposes is DC 347 silicone emulsion manufactured by Dow Coming
Corporation of Midland, Mich. Good water repellency characteristics
have been shown when this agent is present in a ratio of about 1:24
relative to phenolic resin binder. Alternative hydrophobic agents
suitable for use with phenolic resin include Mulrex.RTM., an oil
emulsion marketed by the Mobil Oil Corporation of Fairfax, Va. and
stock number SL 849 oil marketed by Borden Chemical, Inc. of
Columbus, Ohio. Good water repellency characteristics have been
shown when Borden.RTM. SL 849 oil is present in a ratio of about
1:16 relative to phenolic resin binder.
[0034] Although an example is described above in which one portion
12 of the insulating layer includes a hydrophobic agent in the
binder thereof, and another portion 13 of the insulating layer may
not include a hydrophobic agent in the binder thereof, other
embodiments include the hydrophobic agent in the binder of the
entire insulating layer 12, 13. As noted above, if the mat facing
14 provides the desired water repellence (alone or in combination
with a water repellant adhesive 16), then neither portion 12 or 13
requires a hydrophobic agent.
[0035] An exemplary rotary process described above is advantageous
for making a duct board product. In the case of duct liner product,
a similar flame attenuated process is used. Alternatively, a duct
liner product can be fabricated using a textile mat forming
process, in which textile fibers in continuous strands are chopped
into 2 to 5 inch lengths and formed into a mat or board by an
air-laid process. A hydrophobic agent such as a silicone,
fluorocarbon or wax may be added to the powdered binder used in
this process.
[0036] In some embodiments, the water repellency of the duct board
or tube 10 is enhanced by incorporating a hydrophobic agent into
adhesive 16. In this way, liquid water or other aqueous liquids in
the interior of the duct which penetrate facing 14 are repelled
from entering the interior portion 12 of the insulation layer 12,
13 thereby further reducing the likelihood of microbial growth in
the insulation.
[0037] Referring to FIG. 3, insulation layer 12, 13 may be made in
a forming station 19 as described above, by melt spinning molten
material, such as glass, into fine fibers, and spraying a binder,
such as a phenolic resin binder in an aqueous carrier, onto the
fibers, and collecting the fibers as a web on a conveyor. The web
is then passed through a conventional curing oven 30 or other means
for curing and compressing the web to a desired thickness after the
web exits the forming station. Note that portion 13 is not shown in
FIG. 3. For purpose of this example, it is optional, but not
necessary, to have distinguishable portions 12, 13 in the
insulating layer.
[0038] In some embodiments, a continuous web of facing layer 14 is
dispensed from a roll 32 and is applied to one surface of
insulation layer 12 prior to curing of the binder in the
insulation. Prior to adhering the facing layer 14 to the insulation
layer 12, an adhesive 16 is applied to either or both of the facing
layer 14 and the insulation layer 12. Adhesive 16 may be
continuously applied to the underside of facing layer 14 via an
applicator roll 34 rotatably supported in a pan 36 or similar
receptacle which contains adhesive appropriate for securely
adhering layers 12,14 to one another following curing. It will be
understood that adhesive 16 may be applied to either or both of
layers 12, 14 by other means such as spraying or brushing.
[0039] In applying adhesive, care should be taken to minimize the
amount of adhesive 16 that penetrates through the facing all the
way through to the (inner) airstream surface of facing 14 and
becomes deposited on that surface. Adhesive 16 on the inner surface
of mat 14 may present a more wettable surface than the bare facing
14. Thus, if the airstream surface is partially or totally coated
with adhesive 16, this may increase the surface tension of the
surface and reduce water repellence below that of bare facing
14.
[0040] Although not limited thereto, a preferred adhesive is a
phenolic resin having generally the same or similar composition as
the binder that is used to bind the fibers in insulation layer 12.
However, phenolic resin adhesives have limited hydrophobicity.
[0041] Accordingly, the adhesive used to attach facing 14 to
insulation layer 12 may optionally include at least one hydrophobic
agent such as silicone, oil, fluorocarbon, waxes or the like in an
effective amount sufficient to render the product essentially
impermeable to water and resistant to aqueous solutions containing
moderate quantities of solvent, regardless of the water repellency
of the facing 14. Effective amounts of hydrophobic agent may range
in a ratio of about 1:20 to 1:200, and more preferably about 1:40,
hydrophobic agent to binder. A commercially available hydrophobic
agent suitable for these purposes is DC 347 silicone emulsion
manufactured by Dow Corning Corporation of Midland, Mich.
[0042] The layers 12, 14 may travel at any desired synchronous
speed and the applicator roll 24 may be rotated at any speed
sufficient to thoroughly apply the adhesive 16 to the underside of
the moving facing layer web 14. Acceptable results have been
demonstrated at a moving layer speeds of about 80 feet per minute
coupled with applicator roll 24 rotation speeds of about 3-20 rpm.
A placement means 38 such as an idler roller or the like may be
used to facilitate placement of the layer 14 on layer 12. Product
10 is then passed by an unillustrated conveyor to a curing oven 30.
While in the oven, layers 12,14 are simultaneously heated in order
to cure the binder and adhesive 16. Preferably, layers 12,14 are
held together by unillustrated heated platens or the like under
sufficient pressure to compress the facing layer 14 against the
insulation layer 12. Heating the two layers under compression
securely bonds the facing layer 14 to the thermal insulation layer
12. Vapor retarder layer 18 (shown in FIG. 1) may be applied to the
surface of insulation layer 12 opposite facing layer 14 after the
insulation board exits the curing oven. After the curing oven, the
rough edges of the board may also be removed, such as with a
circular saw. The duct board is then cut to length and
packaged.
EXAMPLE
[0043] Samples were constructed with facing 14 made of Johns
Manville 3220B and Lydall Manniglass 1886, on a fiber glass
insulation board with a phenolic binder. The samples were
constructed at different conveyor line speeds of 80 and 92 feet per
minute (which affects the density of the insulating layer 12). In
these samples, hydrophobic agents were not added to the binder of
insulating layer 12, or to the adhesive 16. The results of
evaluating the boards' water repellency by placing drops of water
and water/alcohol solutions on the surface of the board were as set
forth in Table 1. Test results for a commercially available Knauf
Air Duct Board-M with Hydroshield Technology EI475 duct board are
also provided for comparison. The term "OK" indicates that droplets
did not penetrate the surface in the referenced period of time.
1TABLE 1 JM 3220B JM 3220B Lydall 1886 Lydall 1886 Board @80 @92
@80 @92 Knauf Sample feet/minute feet/minute feet/minute
feet/minute Hydroshield Water(100%) OK > 1 hour OK > 1 hour
OK > 1 hour OK > 1 hour OK 15 min 10% OK > 1 hour OK >
1 hour OK > 1 hour OK > 1 hour OK 15 min Isopropanol 20% OK
> 1 hour OK > 1 hour OK > 1 hour OK > 1 hour OK 15 min
Isopropanol 30% OK > 1 hour OK > 1 hour OK > 1 hour OK
> 1 hour Soaked Isopropanol immediately (<1 minute) 40% OK
> 1 hour OK > 1 hour Some soaked OK > 15 Soaked
Isopropanol in <5 minutes minutes immediately (<1 minute) 50%
OK > 1 hour OK > 1 hour Some soaked Some Soaked Soaked
Isopropanol in <5 minutes in <15 immediately minutes (<1
minute)
[0044] An extended test was conducted on the sample prepared using
JM 3220B with a line speed of 80 feet/minute. The sample was placed
under running tap water for over seven hours, at an angle of
approximately 60 degrees from the horizontal, and water dripped
from a height of 13.3 centimeters (5.25 inches). After seven hours,
there was no penetration of water except for the bottom edge of the
board, where water soaked in about 2.5 centimeters (1 inch) from
the edge (In the sample, the mat did not wrap around the bottom
edge, so the bare insulation material was exposed directly to the
running/dripping water stream). A cross section of the board showed
that the portion of the board directly under the drip of water
appeared dry.
[0045] In an alternative embodiment, the duct board or duct liner
product achieves at least an INDA 2 water repellence rating,
meaning the product has sufficient water repellency to repel a
mixture of 20% isopropanol and about 80% water for a minimum of
five minutes using the IST 80.6-92 water repellency test method,
while having a low weight water repellant mat facing 14 thereon. In
one embodiment, the mat facing comprises a nonwoven fiber glass mat
having weight of less than 1.1 lb/100 ft.sup.2 (53.7 g/m.sup.2),
and more preferably less than 1.0 lb/100 ft.sup.2 (48.81
g/m.sup.2). In one exemplary embodiment, the nonwoven fiber glass
mat is the 27# Manniglas.RTM. 1807 mat having a target weight of
0.87 lb/100 ft.sup.2 (42.3 g/m.sup.2 ) and maximum weight of 0.97
lb/100 ft.sup.2 (47.5 g/m.sup.2) available from Lydall Inc., the
23# Manniglas.RTM. 1803WHB mat having a target weight of 0.80
lb/100 ft.sup.2 (39.1 g/M.sup.2) and a maximum weight of 0.90
lb/100 ft.sup.2 (43.9 g/m.sup.2) also available from Lydall Inc. or
a mat having a weight therebetween. These exemplary nonwovens
include an integral water repellent. In an exemplary embodiment,
the nonwoven is combined, such as by saturation, with a water
repellent comprising a fluorinated polymer, such as an fluorinated
acrylic, fluropolymer or flurocarbon, silicone, wax, oil,
wax-asphalt emulsions, acrylics, other emulsions, latexes,
polyvinyl acetates, etc. The weights reflect the combined weight of
the coating and mat. In this embodiment, the desired water
repellency can be achieved without the use of a water repellent
added to the binder of the duct board or adhesive used to adhere
the nonwoven to the duct board.
[0046] By limiting the weight of the nonwoven facing, significant
cost savings can be realized while providing a cost effective,
abuse resistant water repellant airstream surface for the mineral
fiber duct product. Presently, the 23# Manniglas.RTM. 1803WHB mat,
for example, provides roughly a cost savings proportional to the
percentage difference in weight over the heavier Manniglas.RTM.
1886 black models. Additional cost savings can be realized in
embodiments where no additional water repellent is added to the
binder of the duct board or adhesive used to adhere the nonwoven to
the duct board.
[0047] Samples were constructed with facing 14 made of the 23#
Manniglas.RTM. 1803WHB mat having target weight of 39.1 g/m.sup.2,
and the 27# Manniglas.RTM. 1807 mat having target weight of 0.87
lb/100 ft.sup.2 (42.3 g/m.sup.2 ) on a fiber glass insulation board
with a phenolic binder. The 1803 WHB sample achieved an INDA 2.4
rating using the IST 80.6-92 water repellency test method, and the
1807 sample achieved an INDA 2.0 rating using the IST 80.6-92 water
repellency test method.
[0048] Although the invention has been described in terms of
exemplary embodiments, it is not limited thereto. Rather, the
appended claims should be construed broadly, to include other
variants and embodiments of the invention, which may be made by
those skilled in the art without departing from the scope and range
of equivalents of the invention.
* * * * *