U.S. patent application number 12/629184 was filed with the patent office on 2010-04-08 for method and composition for coating mat and articles produced therewith.
This patent application is currently assigned to Atlas Roofing Corporation. Invention is credited to Robert H. Blanpied, Philip BUSH, Jimmy Rogers Dubose, Joseph M. Konieczka, Freddie Lee Murphy.
Application Number | 20100087114 12/629184 |
Document ID | / |
Family ID | 46150427 |
Filed Date | 2010-04-08 |
United States Patent
Application |
20100087114 |
Kind Code |
A1 |
BUSH; Philip ; et
al. |
April 8, 2010 |
METHOD AND COMPOSITION FOR COATING MAT AND ARTICLES PRODUCED
THEREWITH
Abstract
A coated glass mat comprises a glass mat substrate having
non-woven glass fibers and a coating which essentially uniformly
penetrates the glass mat substrate to desired fractional thickness
of the coated glass mat. The coating imparts a tensile strength to
the coated glass mat which on average is at least 1.33 times
greater than the tensile strength of the glass mat substrate
without the coating. In example embodiments, penetration of the
coating into the glass mat substrate preferably extends to a depth
of from twenty five percent of a thickness of the coated glass mat
to seventy five percent of the thickness of the coated glass mat.
Moreover, a non-coated thickness of the coated glass mat is
sufficiently thick for bonding purposes with, e.g., a gypsum slurry
or other core materials such as thermoplastic or thermosetting
plastics. The coating has a porosity in a range of from 1.3 CFM to
5.0 CFM, e.g., the coating comprises a coating blend which provides
the coated glass mat with a porosity sufficient to allow water
vapor to escape from a gypsum slurry when heated. The coating is
preferably a coating blend comprised of water, latex binder,
inorganic pigment, and inorganic binder.
Inventors: |
BUSH; Philip; (Laurel,
MS) ; Blanpied; Robert H.; (Suwanee, GA) ;
Murphy; Freddie Lee; (Meridian, MS) ; Dubose; Jimmy
Rogers; (Lisman, AL) ; Konieczka; Joseph M.;
(Collinsville, MS) |
Correspondence
Address: |
NIXON & VANDERHYE, PC
901 NORTH GLEBE ROAD, 11TH FLOOR
ARLINGTON
VA
22203
US
|
Assignee: |
Atlas Roofing Corporation
Meridian
MS
|
Family ID: |
46150427 |
Appl. No.: |
12/629184 |
Filed: |
December 2, 2009 |
Related U.S. Patent Documents
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Application
Number |
Filing Date |
Patent Number |
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10891485 |
Jul 15, 2004 |
7645490 |
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12629184 |
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10324109 |
Dec 20, 2002 |
7138346 |
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10891485 |
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60341277 |
Dec 20, 2001 |
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Current U.S.
Class: |
442/76 |
Current CPC
Class: |
B28B 23/0006 20130101;
B32B 27/36 20130101; B05C 11/04 20130101; B05C 1/12 20130101; D06N
3/0022 20130101; Y10T 442/2139 20150401; D06N 3/0086 20130101; B32B
17/10018 20130101; D06N 2209/1692 20130101; B28B 19/0092
20130101 |
Class at
Publication: |
442/76 |
International
Class: |
B32B 5/18 20060101
B32B005/18; B32B 5/02 20060101 B32B005/02 |
Claims
1. A coated glass mat comprising: a glass mat substrate having
non-woven glass fibers; a coating comprising latex binder and
inorganic mineral filler, said latex binder comprising polymers
derived from versatic acid and/or versatic acid esters.
2. The coated glass mat of claim 1, wherein the inorganic mineral
filler is comprised of ground limestones.
3. The coated glass mat of claim 1, wherein the latex binder
polymer is comprised of an ester of a versatic acid derivative.
4. The coated glass mat of claim 3, wherein the latex binder
polymer is comprised of an acrylic or vinyl ester of a versatic
acid isomer.
Description
[0001] This application is a continuation of application Ser. No.
10/891,485 (U.S. Patent Application Publication No. US 2005-0103262
A1), filed Jul. 15, 2004 (allowed), which is a continuation-in-part
of application Ser. No. 10/324,109, filed Dec. 20, 2002 (issued as
U.S. Pat. No. 7,138,346 B2), which claims benefit of Provisional
Application No. 60/341,277, filed Dec. 20, 2001, the entire
contents of each of which is hereby incorporated by reference in
this application.
BACKGROUND
[0002] 1. Field of the Invention
[0003] The field of the invention pertains to mats, webs, or facers
for the building construction industry, such as gypsum board
fiberglass facers and thermosetting polyiso foam insulation board
facers, as well as processes for making/applying such facers and
products utilizing such facers.
[0004] 2. Related Art and Other Considerations
[0005] Many forms of weather resistant webbed sheets have been
developed for the building construction industry for installation
as an "underlayment" under shingles or under siding. Examples of
such webbed sheets, also called "construction paper", range from
the old original "tar paper", up to the spun-bonded polyolefin
house wraps of the present day.
[0006] Various types of webbed sheets have also been used as a
"facer" material for foamed insulation board laminates, with the
laminates ultimately being utilized as side-wall or roofing
insulation. For example, two facers for a laminate board typically
sandwich a core material therebetween, e.g., a laminated foam core,
for example. A popular material ("facer") in this category is the
web of U.S. Pat. No. 5,112,678 to Gay et al (referred to herein as
the '678 patent). The relatively fire-resistant web of the '678
patent has also served well as an underlayment in a U.L.
Incorporated fire-resistant rated roofing system over wooden decks,
etc. For many years this material has served the building
construction industry, e.g., as the facer for the laminated foam
board product taught in U.S. Pat. No. 5,001,005. The foam board of
U.S. Pat. No. 5,001,005 remains an important and integral part of
both roofing and side-wall insulation.
[0007] FIG. 1 shows a prior art coating method suitable for
applying coatings such as those of U.S. Pat. No. 5,112,678. A raw
glass mat 10 (e.g., the "substrate") enters a coating station at a
level lower than a top of an applicator roll 12. The direction of
travel of the glass mat 10 is parallel to a "machine direction"
(M.D.) of a facer produced by the machine, while a dimension
perpendicular to the machine direction and perpendicular to the
plane of FIG. 1 is understood to be parallel to a "cross machine
direction" (C.M.D.) of a resultant facer similarly oriented. The
applicator roll is driven to rotate about its axis (either
clockwise or counterclockwise, as depicted by arrow 13). A coating
pan 14 is filled with a coating mix 16 up to a level that is
sufficient for the applicator roll 12 to pull an adequate amount of
coating to the top of the applicator roll 12. The speed of rotation
of applicator roll 12 is used to get adequate amounts of coating
mix 16 up into the glass mat 10 as the glass mat 10 is conveyed. In
its path of conveyance, the glass mat 10 extends around applicator
roll 12 in a wrap-arc 18. A scraper blade 20 is placed so that the
excess coating scraped off returns into the coating pan 14. After
the excess is scraped off, the coated mat proceeds into a dryer
section (not shown) where the coated glass mat facer 22 is dried
and wrapped into rolls.
[0008] The prior art process of FIG. 1 is characterized by a wrap
arc 18 at the applicator roll 12 and a wrap angle 28 at the scraper
blade 20. Conventionally, the wrap arc 18 on the applicator roll 12
is less than 30 degrees, and typically less than 20 degrees. The
wrap angle 28 around the scraper bar 20 is conventionally slightly
less than 180-degrees; e.g., 175-degrees; but, typically no less
than about 175 degrees.
[0009] In the construction industry, building materials are often
analyzed to determine their performance vulnerabilities or weak
points. A vulnerability for a laminated board made with a coated
glass mat facer can be the structural integrity of the glass mat
which comprises the facer. In other words, how well the glass mat
of the facer holds together under stress, e.g., the cohesive
strength (or lack of strength) of the glass mat, is an important
indicia of material quality. Experience has generally shown that
the cohesive strength of any glass mat is typically too low to
resist the pulling-away force of high wind shear vacuums, whether
the glass mat be incorporated either in a stucco wall or under a
fully adhered single-ply membrane roofing system.
[0010] One factor influencing structural integrity of a building
material which incorporates a coated glass mat is the degree to
which glass fibers comprising the mat are uncovered. Uncovered
glass fibers are exposed and thus more subject to deleterious
forces.
[0011] The complications of using coated glass mats as ingredients
in building materials such as a board are compounded when the glass
mats interface with certain other materials which comprise the
board core. One example of such a complicating material is Gypsum.
Many gypsum board applications are subject to structural stress,
and much stronger coated glass mats are required. While the
problems presented by gypsum could perhaps be solved by using
heavier raw glass mat substrates, such an option is quite
expensive. A challenge, therefore, is strengthening the coated
glass mat (e.g., strengthening the facer) without substantially
increasing costs.
[0012] The history of gypsum board development has passed many
milestones, many of these milestones being related to the surfaces,
or facers, covering the broad surface of a gypsum board. In almost
all cases, the subject of facer stability was an issue. Also the
facers have had to resist weathering as well as retaining constant
dimensions. Mildew and mold have been a problem with the original
multi-ply paper facers used on gypsum board. Unfortunately, the
paper facers also might not allow water vapor to escape. Yet the
escape of water vapor is essential in curing the gypsum. While
these paper facers have been modified with chemicals to improve
their properties, most of the gypsum board progress and success has
come by changing from paper facers to fiberglass mat facers.
[0013] The entire scope of manufacturing different facer materials
for building products is extensive, encompassing both fields of
gypsum board fiberglass facers and thermosetting polyiso foam
insulation board facers. In recent years, many facer-related
methods and products thereof have been taught in United States
patents such as the following (all of which are incorporated herein
in their entirety by reference):
TABLE-US-00001 3,284,980 3,993,822 4,504,533 4,637,951 4,647,496
4,784,897 4,810,569 4,879,173 5,112,678 5,148,645 5,171,366
5,220,762 5,319,900 5,342,566 5,342,680 5,371,989 5,395,685
5,397,631 5,401,588 5,552,187 5,601,888 5,644,880 5,665,442
5,718,785 5,791,109 5,945,182 5,945,208 5,965,257 6,001,496
6,146,705 6,299,970
[0014] As alluded to above, some coated glass mat prior art facer
products are ineffective or unusable as a facer for a gypsum board.
For example the coated glass mat of U.S. Pat. No. 5,965,257 shows
signs of dissolving when subjected to a stream of running water,
and has low tensile test numbers (e.g., when compared to the mat
made from the '678 patent).
[0015] A gypsum board used in construction is much heavier than a
low density, lightweight insulation foam board. The gypsum board
must have enough structural strength to avoid breaking while being
handled during installation. The facers of gypsum board provide
most of the structural strength needed. The prior art multi-ply
paper-board facers possess ample tensile strength for use as
facers. However, the ordinary prior art coated glass mat facers do
not have adequate tensile strength. In addition to lacking tensile
strength, ordinary coated glass mat facers can face difficulty in
becoming adequately bonded to the gypsum slurry.
[0016] Thus, as indicated above, conventionally a laminated board
has a core which is sandwiched between two facers, the facers each
comprising a coating material on a glass mat. It is the interface
between the core and the glass mat where failure can occur under
conditions of high stress in the "pull-apart" direction. As
previously mentioned, the failure occurs because some fibers are
left uncovered and the bonding strength of the so-called "binder"
material between individual glass fibers is not strong enough to
prevent failure. Just after a non-woven glass mat is formed on a
drainage wire, a complex binder chemical is added, but this is
barely strong enough to hold individual fibers together.
[0017] U.S. Pat. No. 4,647,496, No. 4,810,569, No. 5,371,989, No.
5,644,880, and No. 6,001,496, show how a glass mat can be partially
imbedded in gypsum board but leave loose glass fibers on the
surface.
[0018] In a gypsum board process which utilizes a coated glass mat
in a facer, a fine balance must be achieved. If the coated glass
mat facer has too much glass mat exposed such that the liquid
gypsum slurry cannot cover it essentially entirely, the resultant
board is unacceptable. On the other hand, if not enough glass
fibers (which serve to anchor the gypsum) are left exposed, the
resultant board is not acceptable. In both cases, the finished
board can fail a flexural stress test, or worse, break at the
job-site. Thus a coated glass mat facer must have both adequate
tensile strength plus the ability to become tightly bonded and
intermeshed with gypsum slurry before it hardens. Since prior art
facers did not suffice, there remains a need for an unique coated
glass facer to use in creating a gypsum board having a mold
resistant, weather-proof surface, and strong flexural test
results.
[0019] What is needed, therefore, and an object of the present
invention, is a coated glass mat which has enhanced tensile
strength, as well as methods for fabricating such mat.
BRIEF SUMMARY
[0020] A coated glass mat comprises a glass mat substrate having
non-woven glass fibers and a coating. The coating essentially
uniformly penetrates the glass mat substrate to a desired
fractional thickness of the coated glass mat. The coating imparts a
tensile strength to the coated glass mat which on average is at
least 1.33 times greater than the tensile strength of the glass mat
substrate without the coating. On average, the weight of the coated
glass mat per unit area is no more than about six times the weight
of the glass mat substrate prior to coating.
[0021] In example embodiments, penetration of the coating into the
glass mat substrate preferably extends to a depth of from twenty
five percent of the thickness of the coated glass mat to seventy
five percent of the thickness of the coated glass mat. Moreover, a
non-coated thickness of the coated glass mat is sufficiently thick
for bonding purposes with, e.g., a gypsum slurry or other core
materials such as thermoplastic or thermosetting plastics.
[0022] The coating comprises a coating blend which provides the
coated glass mat with a porosity sufficient to allow water vapor to
escape from a gypsum slurry when heated. Preferably, such porosity
is in a range from about 1.3 Cubic Feet per Minute (CFM) (all CFM
data given are also "per square foot") to about 5.0 CFM. The
coating is preferably a coating blend comprised of water, latex
binder, inorganic pigment, and inorganic binder. The CFM (Cubic
Feet per Minute per Square Foot) porosity data shown in various
Tables herein are determined by using ASTM D 737-96, "Standard Test
Method for Air Permeability of Textile Fabrics."
[0023] The raw glass mat substrate has a weight which is between
about twelve (12) pounds per thousand square feet and about fifty
(50) pounds per thousand square feet. In one example, the glass mat
substrate before coating weighs about fourteen and a half (14.5)
pounds per thousand square feet. After coating the coated glass mat
has a tensile strength which on average is greater than one hundred
twenty pounds per three-inch width. In another example, the glass
mat substrate before coating weighs about twenty-six and a half
(26.5) pounds per thousand square feet. After coating the coated
glass mat has a tensile strength which on average is greater than
two hundred twenty pounds per three-inch width.
[0024] New coating methods which yield the coated glass mat expose
a sufficient amount of coating to the glass mat to provide a
uniform depth penetration and thereby achieve the increased tensile
strength. The method facilitates a high degree of coating depth
penetration (e.g., up to 75%) and yet no significant change in
coating percentage composition by weight per square unit area.
Because of the new coating techniques, the prior art glass mat
substrate has a disproportionate increase in tensile strength
relative to the increase in final product weight. The coated glass
mat webs are much stronger and more weatherproof than prior art
similar webs.
[0025] One of the new coating techniques involves increasing a wrap
angle of the glass mat substrate around an applicator roll thereby
increasing exposure of the coating to the glass mat substrate.
[0026] Other new coating techniques, which permits utilization of a
non-increased wrap angle, involves providing a friction-enhancing
surface configuration for the application roller, e.g., a surface
configuration that is non-smooth and which has greater friction
than a smooth surface. In one embodiment, the friction-enhancing
surface configuration can involve scoring, cutting, or otherwise
forming grooves or depressions in an exterior surface of the
applicator roll. In another embodiment, which also permits
utilization of a non-increased wrap angle, involves coating or
otherwise applying a rough surface material to an exterior surface
of an applicator roll. Other techniques also provide a substantial
increase in tensile strength.
BRIEF DESCRIPTION OF THE DRAWINGS
[0027] FIG. 1 is a schematic view of apparatus utilized in prior
art coating process for a glass mat.
[0028] FIG. 2 is a schematic view of a first embodiment of
apparatus utilized in a coating process which achieves improved
coating exposure and uniform penetration.
[0029] FIG. 3A is a schematic cross-sectional view of a section of
a side view of a coated glass mat fabricated in accordance with
Example 1.
[0030] FIG. 3B is a photomicrograph of a coated glass mat
fabricated according to Example 1.
[0031] FIG. 4A is a schematic cross-sectional view of a section of
a side view of a coated glass mat fabricated in accordance with
Example 4.
[0032] FIG. 4B is a photomicrograph of a coated glass mat
fabricated according to Example 4.
[0033] FIG. 5A is a schematic cross-sectional view of a section of
a side view of a coated glass mat fabricated in accordance with
Example 5.
[0034] FIG. 5B is a photomicrograph of a coated glass mat
fabricated according to Example 5.
[0035] FIG. 6 is a schematic view of another embodiment of
apparatus utilized in a coating process which achieves improved
coating exposure and uniform penetration.
[0036] FIG. 6A, FIG. 6B, FIG. 6C, FIG. 6D, and FIG. 6E are top
views of application rolls utilized in differing implementations of
the embodiment of FIG. 6.
[0037] FIG. 7 is a schematic view of yet another embodiment of
apparatus utilized in a coating process which achieves improved
coating exposure and uniform penetration.
[0038] FIG. 7A is a top view of an application roll utilized in the
embodiment of FIG. 7.
DETAILED DESCRIPTION
[0039] In the following description, for purposes of explanation
and not limitation, specific details are set forth such as
particular compositions, techniques, etc. in order to provide a
thorough understanding. However, it will be apparent to those
skilled in the art that the present invention may be practiced in
other embodiments that depart from these specific details. In other
instances, detailed descriptions of well known substances and
methods are omitted so as not to obscure the description of the
present invention with unnecessary detail. It will be further
understood that in the ensuing description and claims that the
terms "web" and "mat" are employed interchangeably, and in the
sense that the mats and webs can be used as "facers", all three
terms may be utilized interchangeably.
[0040] A coated glass mat suitable for use, e.g., as a facer in a
plastic foam board, or a gypsum board, or a composite wood particle
board, or plywood, or any other type of building construction
board, is formed by a process which uses a substantially porous,
predominately glass mat substrate. The glass mat substrate
comprises non-woven glass fibers. The coating of the coated glass
mat advantageously penetrates deeply into the thickness of the mat,
e.g., from approximately 25% up to 75% of the mat thickness,
thereby affording higher tensile strengths. To whatever depth in
this range (25% up to 75% of the mat thickness) the coating
extends, it does so essentially uniformly. The uniformly deep
penetration is achieved by one or more new coating techniques which
facilitate increased exposure of coating mixture to a glass mat
substrate, thereby achieving more uniform coating penetration. Yet
compared to prior art mats the coated glass mat has about the same
coating percentage composition by weight per square unit area. The
uncoated thickness (e.g., approximately 25% up to 75% of the
thickness) of the glass mat is sufficiently thick for bonding
purposes with, e.g., a gypsum slurry or other core materials such
as thermoplastic or thermosetting plastics. The raw, uncoated glass
mat substrate has a weight which is between about twelve (12)
pounds per thousand square feet and about fifty (50) pounds per
thousand square feet. An example coating batch for use in forming
the coated glass mat is provided in Example 1.
[0041] The porosity of the coated glass mat is sufficiently low
that it is not penetrable by gypsum slurry, yet porous enough to
allow water vapor to escape from the gypsum slurry when heated, and
porous enough to allow thermoplastic or thermosetting plastics, or
gypsum slurry, to completely cover essentially all exposed,
individual glass fibers. Preferably the porosity of the coated
glass mat is in a range of from about 1.3 CFM (cubic feet per
minute per square foot) to about 5.0 CFM.
[0042] The improved coating techniques thus facilitate increased
exposure of the coating mixture to a glass mat substrate, and
thereby a uniformly deeper penetration of the coating into the
interior spaces of the glass mat. The penetration is to a depth of
at least 25%, but preferably less than about 75%, of the thickness
of the mat, i.e., not so far that it penetrates entirely. Such
increased exposure and uniformly deep penetration is accomplished
by various techniques including but not limited to those
hereinafter specifically described.
[0043] There are various mechanical techniques for achieving the
increased exposure and uniform coating penetration depth in the
glass mat. Some of the techniques, described subsequently, involve
configuring or contouring an exterior surface of the applicator
roll so that the exterior surface is non-smooth, thereby providing
a friction-enhancing surface configuration for the application
roller, e.g., a surface configuration that is non-smooth and which
has greater friction than a smooth surface. Other techniques
involve configuring a path of travel of the glass mat and thus
include the following as examples: (1) selecting a proper wrap
angle for the scraper blade (in degrees of angle); and, (2)
selecting a proper wrap arc on the applicator roll (in degrees).
One, or the other, or both, of these web path techniques may be
employed, but it must be noted that the wrap angle at the scraper
blade is dependent upon the degree of wrap-arc at the applicator
roll, and vice versa. An example mode of the wrap selection
technique is described below with reference to FIG. 2.
[0044] FIG. 2 shows basic apparatus utilized in an example mode of
the improved coating process which achieves the desired increased
exposure of the coating mixture to the glass mat substrate.
Structural elements of the FIG. 2 apparatus which correspond to
elements of the FIG. 1 apparatus have same least two significant
digit reference numbers.
[0045] In contrast to the prior art process of FIG. 1, the process
implemented by the FIG. 2 apparatus utilizes a higher degree of
wrap-arc 118 around the applicator roll 112 (more than about 30
degrees) and a smaller wrap angle 128 around scraper blade 120
(less than about 175-degrees). This tighter (or shaper) wrapping
method provides an is increased exposure of coating mixture 116 to
the glass mat substrate 110, and thereby a higher degree of uniform
coating penetration into the glass mat. The degree of penetration
is between approximately 25% up to 75% of the thickness into the
glass mat substrate. In this coating method, the wrap-arc 118 is
much larger (above about 30-degrees) than wrap-arc 18 of FIG. 1.
Specifically, wrap-arc 118 on the roll 112 is in a range from about
30 degrees to 80 degrees depending upon other operational
parameters (such as, for example, speed of applicator roll 112).
Likewise, wrap angle 128 of FIG. 2 is noticeably sharper than wrap
angle 28 of the prior art. In the FIG. 2 embodiment, the wrap angle
128 on blade 120 is about 160-degrees to about 175-degrees.
[0046] It should be understood that it is the degree of exposure of
the coating material 116 to the glass mat substrate 110 that is
increased by the new processing techniques and which results in the
more uniform penetration of the coating into the glass mat
substrate. The degree of exposure or availability of the coating
116 is a different phenomena than the actual amount of acquisition
by glass mat substrate 110 of the coating mixture. Indeed, using
the new exposure enhancing technique, no more coating is actually
applied for penetration into the glass mat substrate. Rather, there
is more opportunity for uniform acquisition of the coating 116 by
the glass mat substrate 110.
[0047] The coating industry has used the "1-Roll Kiss Coater" for
many years. A kiss-roll applicator is normally followed by a
grooved rod, but glass mat will destroy such a rod in a matter of
minutes. However, a modification to the trailing blade method does
work when, if an excess amount of relatively low viscosity coating
mix 116 is applied to the bottom surface of the glass mat 110, and
the excess is scraped off with blade 120. It is believed that the
combination of a kiss-roll followed by a monolithic scraper blade
is a new and unique combination.
[0048] Although FIG. 2 and other drawings are not necessarily to
scale, the relative dimensions have been depicted to show actual
spatial relationships. They only approximately represent the path
of a raw glass mat substrate as it passes through a coating
station. The approximate wrap angles 118 over applicator roll 112
and 128 over the scraper blade 120 are shown to represent a
definite deviation from zero wraps.
[0049] In lieu or in addition to the proper setting of wrap arc 118
and wrap angle 128, there are at least eight (8) other techniques
that can be utilized to increase the degree of exposure of the
coating 116 to the glass mat substrate 110. These techniques are:
(1) adjusting the speed of the coating line; (2) adjusting the
viscosity of the coating mix; (3) adjusting the direction of the
applicator roll rotation; (4) selecting a proper diameter of the
coating applicator roll; (5) adjusting the speed of the applicator
roll rotation; (6) selecting a proper surface material of the
applicator roll; (7) controlling the thickness of the glass mat
web; and (8) controlling the porosity, in cubic feet of air per
minute per square foot, of the glass mat web.
[0050] It was mentioned previously that the wrap-arc 118 of the
FIG. 2 apparatus is in a range of from about 30 degrees to about 80
degrees. In one example, the wrap-arc 118 extends about 80 degrees
and the applicator roll is rotated at a nominal angular velocity
which is just slightly faster than the linear velocity of the glass
mass substrate. Yet in another example, the wrap-arc 118 extends a
lesser amount (e.g. 40 degrees), but the applicator roll is driven
at an increased angular velocity which affords essentially the same
exposure as the first example. Thus, the new techniques can be
combined in order to achieve the desired exposure of the coating
116 to the glass mat substrate 110, thereby enhancing uniform
coating penetration. The uniform coating penetration facilitates
the improved tensile strength of the coated glass mat, e.g., a
tensile strength in the machine direction which is at least 1.33
times greater than that of the glass mat substrate prior to
coating.
[0051] FIG. 6 illustrates another technique for increasing the
degree of exposure of the coating to the glass mat substrate, in
particular a technique which involves treating, configuring, or
contouring an exterior surface of the applicator roll. The FIG. 6
apparatus resembles the apparatus of FIG. 1, with similar elements
having similar two least significant digit reference numerals. In
the apparatus of FIG. 6, applicator roll 212 has grooves 232
scored, cut, or otherwise formed on its exterior surface.
Preferably the grooves 232 are formed along the entire width of the
applicator roll 212, i.e., in a direction parallel to the major
axis of the roll 212, as shown in FIG. 6A. Alternatively, the
applicator roll 212 may be formed with dimples or depressions which
are not necessarily elongated along the major axis of applicator
roll 212.
[0052] FIG. 7 illustrates yet another technique for increasing the
degree of exposure of the coating to the glass mat substrate, in
particular a technique which involves coating or otherwise applying
a rough surface material 330 to an exterior surface of applicator
roll 312. The thickness of the rough surface material 330 is
exaggerated in FIG. 7 for sake of clarity. FIG. 7A shows one mode
of implementing the embodiment of FIG. 7, which involves a
substantially even application of fine and unusually hard sand
particles on the exterior of applicator roll 312. In other
respects, the FIG. 7 apparatus resembles the apparatus of FIG. 1,
with similar elements having similar two least significant digit
reference numerals.
[0053] Although the wrap angles 218 and 318 of the FIG. 6 and FIG.
7 apparatus are more conventional, e.g., the same or on the order
of the wrap angle 18 of the FIG. 1 apparatus, the provision of such
grooves 232 in the FIG. 6 embodiment or such coating 330 in the
FIG. 7 embodiment accomplishes essentially the same degree of
coating penetration as did sharpening the wrap angle from the angle
18 shown in FIG. 1 to the wrap angle 118 shown in FIG. 2. Thus, the
advantageous increase in tensile strength herein described can also
be obtained using the prior art wrap angles 18 (in FIG. 1) as long
as the applicator roll has either been treated with rough surfacing
material or scored substantially along its width.
[0054] Concerning the FIG. 6 embodiment, the grooves 232 can be
formed in a gravure roll and are preferably about 0.020 inch to
0.050 inch (i.e., 20 mils to 50 mils) deep, and more preferably
between about 0.020 inch to 0.050 inch deep. As mentioned before,
in lieu of elongated grooves, small depressions in the form of
exterior cups or holes of this depth range can be formed on the
applicator roll 212.
[0055] Whereas FIG. 6A shows application roll 212 as having only
parallel longitudinal grooves 232, other groove orientations and
configurations are also possible. For example, FIG. 6B shows
application roll 212B as having not only longitudinal grooves 232,
but also circumferential grooves 233 preferably equally spaced
between ends of the roll. The circumferential grooves 233 can be
perpendicular to the longitudinal grooves 232 in the manner shown
in FIG. 6B. Alternatively, as shown in the embodiment of FIG. 6C,
the circumferential grooves 234 can be skew to the longitudinal
grooves 232 and yet parallel to one another. Yet further
embodiments are also possible, such as that of FIG. 6D having
parallel grooves 235 and parallel grooves 236, with neither grooves
235 nor 236 being parallel to the major axis of applicator roll
212E, and with the grooves 235 and 236 being either in orthogonal
or non-orthogonal relationship. For example, the grooves can be cut
in the manner of FIG. 6E so that two spirals 237 and 238 are formed
with the starting point in the center. When rotating bottom-to-top,
the dual spirals 237 and 238 tend to stretch the substrate toward
both ends, thus helping the substrate lay flat.
[0056] Whatever configuration of grooved contour is selected for
the applicator roll of an embodiment such as that of FIG. 6A-FIG.
6E, the grooves increase the friction between the applicator roll
212 and the coating mixture 216 in coating pan 214, and thus
increase the pick up of the coating mix, and thus facilitate the
desirable increased penetration described herein.
[0057] Likewise, the rough surface treatment or coating of the FIG.
7 embodiment also increases the friction between the applicator
roll 312 and the coating mixture 316 in coating pan 314, and thus
increase the pick up of the coating mix, and thus facilitate the
desirable increased penetration described herein.
[0058] Apparatus such as that of FIG. 6 and FIG. 7 avoids shaper
wrap angles such as those shown in FIG. 2. Such may be an advantage
in any implementations in which the sharper wrap angle cause
increased wear for the applicator roll and scraper blade.
[0059] In a preferred implementation of the FIG. 7 embodiment, the
applicator roll 312 is coated with Racine Flame Spray RFS 5136 Fine
Grade Chromium Oxide-Silicone Dioxide composite powder. At
approximately 25-mils thick, the finished coating has a 250-300 RMS
surface with a Rockwell C hardness of 70-72. In another preferred
embodiment, the surface scoring process is the common gravure
engraving used for solid ink coverage in printing.
[0060] Thus it will be understood that various mechanical ones of
the techniques aforementioned can be employed to increase exposure
of the coating to the substrate in a comparable manner. Usage of
these techniques presumes, however, that the viscosity of the
coating is in a suitable range, and has sufficient solids content.
That is, the coating must be sufficiently viscous that it does not
fly off the mat during the travel between applicator roll and
blade, and yet not so viscous that it cannot be picked up by
applicator roll.
[0061] In one particular mode, an electric motor driven, RFS
5136-treated applicator roll 312 is used. However, it is possible
to use plain steel, chrome plated, rubber or plastic coated rolls,
or stainless steel rolls. The applicator roll 312 is powered to
rotate in the same direction as the web, and is rotated slightly
faster than the web. The scraper blade can be made of either carbon
steel, or hardened steel, or spring steel, or tungsten-carbide
steel, or from various grades of ceramics.
[0062] In some embodiments it is preferred that the wrap angle on
the blade be from about 175-degrees to about 178-degrees, and the
wrap arc on the roll be about 20-degrees to about 30-degrees,
depending on other variables.
[0063] The prior art coating mixes can be utilized with the
uniformly deeper penetration processing techniques herein
described. For example, in one mode, filler materials containing
some naturally occurring inorganic binder are deliberately chosen.
These fillers with naturally occurring binders must be of a
suitable mesh size. The minimum allowable quality is where at least
85% by weight of the filler passes a 200-mesh screen (Grade
85/200). Examples of such fillers having the naturally occurring
binder are, but are not limited to: limestone containing quicklime
(CaO), clay containing calcium silicate, sand containing calcium
silicate, aluminum trihydrate containing aluminum oxide, and
magnesium oxide containing either the sulfate or chloride of
magnesium, or both. The filler, gypsum, can be both a mineral
pigment (as gypsum dihydrate) and a binder (as gypsum
hemi-hydrate), but gypsum is slightly soluble in water, and the
solid form is crystalline making it a brittle and weak binder.
[0064] Various examples are now described for contrasting coated
glass fabricated with prior art coating processes (see Example 1
and Example 2) with coated glass mats which utilize the increased
exposure techniques herein described.
Example 1
Prior Art
[0065] For Example 1, a batch of coating mixture is made by adding
3,200 pounds of water to a mixing tank having a low speed mixer.
This is followed by 80 pounds of a sodium salt of
poly-naphthylmethanesulfonate dispersing agent, such as
Galoryl.RTM. DT 400 N. Then is added 950 wet pounds (498.8 dry
pounds) of a carboxylated SBR latex, such as Styrofan.RTM. ND5406,
followed by 11,000 pounds of 85/200 (85% passes a 200-mesh screen)
limestone that contains about 70 pounds of calcined lime (CaO).
This produces a 15,230-pound batch of coating mixture having about
75.7% solids and with a viscosity of about 300 centipoise (cps) at
25.degree. C. The quicklime (CaO) content is about 0.6% by weight
on the total dry-weight basis. The latex solids comprise about 4.3%
on the dry weight basis.
[0066] The coating mixture of Example 1, produced in accordance
with U.S. Pat. No. 5,112,678, was (for Example 1) applied using the
prior art process of FIG. 1 to a non-woven glass mat
Dura-Glass.RTM. 7503 made by Johns Manville. The glass mat weight
averaged about 13.9-lbs/MSF (thousand square feet), and had a
thickness average of about 0.023-inches. The final coated product
weight averaged about 84.8-lbs/MSF, indicating that the coating
solids added 70.9-lbs/MSF.
[0067] FIG. 3A depicts a section of a side view of a coated glass
mat 40(3) made fabricated in accordance with Example 1. The coated
glass mat of FIG. 3A is made from the 14.5-lbs/MSF raw glass mat
substrate (Dura-Glass.RTM. 7503), with a final coated product
weight averaging about 85.0-lbs/MSF (indicating that the coating
solids added 70.5-lbs/MSF). For the coated glass mat of FIG. 3A,
the thickness dimension (represented by reference numeral 42(3)) is
about 0.026-inches. The measured thickness of the coating
penetration is depicted by arrow 44(3), while the thickness of the
portion remaining uncoated is labeled by arrow 46(3).
[0068] By the use of a common laboratory microscope, it was
discovered that of the total finished mat thickness of FIG. 3A, the
coating material penetrates from about 10% up to about 25%. Said
another way, the ratio of coating penetration thickness 44(3) to
non-coated thickness 46(3) is about 25 to 75. The portion having
the uncoated glass fibers is employed in holding the core material
(e.g., polyiso foam), making a reasonably strong laminated panel as
taught by U.S. Pat. No. 5,001,005. A photomicrograph of a coated
glass mat according to Example 1 is shown in FIG. 3B.
[0069] Table 1 shows thirty (30) samples of tensile test data
generated for the coating and prior art processing techniques of
Example 1, as well as average tensile test data, a standard
deviation, and a range. For each sample, tensile test data for the
resultant coated glass mat is supplied in column 1 with respect to
the machine direction (M.D.), and in column 2 with respect to the
cross-machine direction (C.M.D.) dimension of the glass mat. All
tensile strength values provided herein (including those listed in
Table 1 and other tables) are in units of pounds per three inch
wide strip of coated glass mat, e.g., "pounds-per-three-linear
inches width", e.g., "lbs./3-L.I.". The test method used is TAPPI T
1009 om-92, "Tensile Strength and Elongation At Break".
[0070] Prior to coating, the glass mat substrate of Example 1 had
an average nominal tensile strength in the machine direction of 90
pounds per three inch width and an average tensile strength in the
cross machine direction of 60 pounds per three inch width. From
Table 1 it can be seen that the coating imparts a tensile strength
to the coated glass mat which, on average, is less than 1.10 times
greater in the machine direction than the tensile strength of the
glass mat substrate in the machine direction prior to coating.
Example 2
Prior Art
[0071] As Example 2, a coated glass mat facer fabricated by Elk
Corporation in accordance with the prior art process of U.S. Pat.
No. 5,965,257 and known as "ISO FACER 1" was evaluated. The coated
glass mat facer of Example 2 weighed about 99-lbs/MSF, and measured
(with a caliper) a thickness of about 0.034-inches. Thirty samples
of tensile test data for the mat of Example 2 are shown in Table 2,
the first column of Table 2 showing tensile test data with respect
to the machine direction (M.D.) and the second column showing
tensile test data with respect to the cross-machine direction
(C.M.D.).
[0072] Comparison of the tensile strengths for Example 1 and
Example 2 as set forth in Table 1 and Table 2, respectively, show
that even with more thickness and higher weight, the product of
Example 2 is considerably weaker than the product made as Example
1. Yet both Example 1 and Example 2 pale in contrast to the
substantially higher tensile strengths achieved by the remaining
Examples, the higher tensile strength being advantageously achieved
without increases in weight or thickness.
[0073] Concerning the data of Table 1 and Table 2, the sample size
tested was 3-inches wide by 10-inches long, with 1-inch at each end
inside the jaws, and the tensile test jaws were pulled at the speed
of 1-inch per minute. Those familiar with test results of uncoated
glass mat will note that the Standard Deviation is very similar to
the tensile test Sigma of plain glass mat. In other words, the wide
range of test scores for tensile testing are built into the glass
mat as produced, and coating the mat has no effect on that wide
range other than raise the individual numbers.
Example 3
[0074] Example 3 utilized the same coating batch mixture as Example
1. The coating of Example 3 was applied to a glass mat using the
process of FIG. 2. The glass mat weighed 14.5-pounds per MSF
(thousand square feet).
[0075] Table 3 shows samples of tensile strength data for Example
3. As with the Table 4 mats discussed subsequently, for the Table 3
mats the sample size tested was 3-inches wide by 10-inches long,
with 1-inch at each end inside the jaws, and the tensile test jaws
were pulled at the speed of 1-inch per minute. The coated glass
mats of Example 3 had an average thickness of 0.026-inches and
weighed an average of 85-lbs per 1,000-square feet (MSF). Of that
finished weight, about 70.5-lbs/MSF was coating and 14.5-lbs/MSF
was glass mat.
[0076] Prior to coating, the glass mat substrate of Example 3 had
an average nominal tensile strength in the machine direction of 90
pounds per three inch width and an average tensile strength in the
cross machine direction of 60 pounds per three inch width. From
Table 3 it can be seen that the coating imparts a tensile strength
to the coated glass mat which, on average, is at least 1.33 times
greater in the machine direction than the tensile strength of the
glass mat substrate in the machine direction prior to coating. In
particular, for Example 3 the coating imparts a tensile strength to
the coated glass mat which is, on average, 1.37 times greater than
the tensile strength of the glass mat substrate prior to coating.
When the term "tensile strength" is utilized herein without
reference to direction, it is understood to refer to tensile
strength in a machine direction.
[0077] The constituency of the coating and degree of application of
the coating for Example 3 is such that, on average, the weight of
the coated glass mat per unit area after coating is no more than
six times the weight of the glass mat substrate before coating.
That is, the coating weight is less than five (5) times the weight
of the glass mat substrate (prior to coating). The average porosity
for the coated glass mat of Example 3 is between 3.8 CFM and 3.9
CFM.
Example 4
[0078] The coating batch for Example 4 was the same as for Example
1, but was applied using the process of FIG. 2 to a glass mat
(Dura-Glass 7503) sold as weighing 14.5-pounds per MSF (thousand
square feet), but actually weighing 14.9-pounds per MSF. The coated
glass mat weighed 89.1-pounds per MSF on average. As with the
Example 1 mats, the Example 4 mat sample size tested was 3-inches
wide by 10-inches long, with 1-inch at each end inside the jaws,
and the tensile test jaws were pulled at the speed of 1-inch per
minute. Approximately the same coating weight was applied (an
average of 74.2-pounds/MSF), but the improved processing techniques
made the coating penetrate more uniformly and further into the
glass mat substrate. In doing this, the approximate same coating
weight created a final product with substantially higher tensile
strength, as indicated by Table 4.
[0079] FIG. 4A depicts a cross section of a coated glass mat 40(4)
fabricated in accordance with Example 4. The thickness dimension
(represented by reference numeral 42(4)) of coated glass mat 40(4)
is about 0.026-inches. The measured thickness of the coating
penetration is depicted by arrow 44(4), while the thickness of the
portion remaining uncoated is labeled by arrow 46(4). By the use of
a common laboratory microscope, it was discovered that of the total
finished mat 40(4) thickness (0.026 inches), the coating material
penetrates about 70% (seventy percent), or about 0.014-inches. Said
another way, the ratio of 44(4) to 46(4) is about 70-to-30. The
portion of uncoated glass fibers that successfully hold gypsum
slurry and other core materials such as thermoplastic and
thermosetting plastics. FIG. 4B is a photomicrograph of a coated
glass mat fabricated according to Example 4.
[0080] Prior to coating, the glass mat substrate of Example 4 had
an average nominal tensile strength in the machine direction of 90
pounds per three inch width and an average tensile strength in the
cross machine direction of 60 pounds per three inch width. From
Table 4 it can be seen that the coating imparts a tensile strength
to the coated glass mat which, on average, is at least 1.33 times
greater in the machine direction than the tensile strength of the
glass mat substrate in the machine direction prior to coating. In
particular, for Example 4 the coating imparts a tensile strength to
the coated glass mat which is, on average, 1.46 times greater than
the tensile strength of the glass mat substrate prior to
coating.
[0081] The constituency of the coating and degree of application of
the coating for Example 4 is such that, on average, the weight of
the coated glass mat per unit area after coating is no more than
about six times the weight of the glass mat substrate before
coating. That is, the coating weight is less than five (5) times
the weight of the glass mat substrate (prior to coating). The
average porosity for the coated glass mat of Example 3 is between
1.5 CFM and 1.6 CFM.
[0082] The tensile strengths of the glass mat facers of Example 4
which have the deeper coating penetration are 62.2% better in the
machine direction (M.D.), and 84.3% better in the cross machine
direction (C.M.D.) than the glass mat facers of Example 2; and,
33.3% better in the machine direction (M.D.), and 34.2% better in
the cross machine direction (C.M.D.) than the glass mat facers of
Example 1.
Example 5
[0083] The coating batch for Example 5, like that of Example 4, was
the same as for Example 1, but was applied using the process of
FIG. 2 to a glass mat (Dura-Glass 7503) weighing 26.5-pounds per
MSF (thousand square feet). The Example 5 mat sample size tested
was 3-inches wide by 10-inches long, with 1-inch at each end inside
the jaws, and the tensile test jaws were pulled at the speed of
1-inch per minute. The tensile strength for the mats of Example 5
are shown in Table 5.
[0084] FIG. 5A is a side cross-sectional view of a coated glass mat
40(5) fabricated in accordance with Example 5. Example 5 utilized a
heavier and stronger glass mat substrate weighing 26.5-pounds per
MSF (thousand square feet). In FIG. 5A, the total thickness
dimension depicted by arrow 42(5) is about 0.036-inches thick. In
the Example 5 coated mat 40(5), the coating permeates into the
glass mat to a depth depicted by arrow 44(5), leaving an uncoated
portion of thickness indicated by arrow 46(5). The thickness
(depicted by arrow 42(5)) of the total finished coated mat 40(5) is
on the order of 0.036-inches. Microscopic analysis shows that the
coating material penetrates to about 75% (seventy-five percent), or
0.027-inches. Thus the ratio of coated thickness to uncoated
thickness is about 75-to-25. Although the coated mat 40 of Example
5 comprises a lower total weight of coating, the coating penetrates
to a greater thickness, thereby covering more glass fibers.
Therefore, the coating is less dense. FIG. 5B is a photomicrograph
of a coated glass mat fabricated according to Example 5.
[0085] The weight of this finished product of Example 5 was
87.5-lbs/MSF, surprisingly only 3.2% heavier than the prior art
coated mat using 14.5-lbs/MSF glass mat substrate. The Example
5/Table 5 coated glass mat is comprised of 26.5-lbs/MSF of uncoated
glass mat (substrate) plus only 61.0-lbs/MSF coating. The amount of
the coating added was lower than for the coated mats of Table 1 and
Table 2 (e.g., the coated mats which used the 14.5-lbs/MSF mat) The
lighter mat consistently picked up over 70.0-lbs/MSF, whereas the
26.5-lbs/MSF mat picked up only 61.0-lbs/MSF.
[0086] Prior to coating, the glass mat substrate of Example 5 had
an average nominal tensile strength in the machine direction of 90
pounds per three inch width and an average tensile strength in the
cross machine direction of 80 pounds per three inch width. From
Table 5 it can be seen that the coating imparts a tensile strength
to the coated glass mat which, on average, is at least 1.33 times
greater in the machine direction than the tensile strength of the
glass mat substrate in the machine direction prior to coating. In
particular, for Example 5 the coating imparts a tensile strength to
the coated glass mat which is, on average, 3.00 times greater than
the tensile strength of the glass mat substrate prior to
coating.
[0087] The constituency of the coating and degree of application of
the coating for Example 5 is such that, on average, the weight of
the coated glass mat per unit area after coating is no more than
six times the weight of the glass mat substrate before coating. In
particular, for Example 5 the weight of the coated glass mat per
unit area after coating is only about 3.3 times the weight of the
glass mat substrate before coating. That is, the coating weight is
less than five (5) times the weight of the glass mat substrate
(prior to coating).
[0088] So with a very small increase in total product weight (3.2%
increase), the tensile strength in the machine direction was
improved 274% (270.7/98.8.times.100), and in the cross-machine
direction by 246% (199.6/81.3.times.100). This average increase of
about 260% in overall tensile was better than expected.
Example 6
[0089] The coating batch of Example 6 was made utilizing water
(2335-lbs); Galoryl.RTM. DT 400 N (45.5-lbs); Dow's NeoCAR-820
latex (1440-lbs); Engelhard W-1241, which is a dispersed yellow
colorant (27.5-lbs); and a mineral pigment filler in the form of
limestone, particularly Franklin Mineral's Lowell 90/200
(9512-lbs). This 13360-lb. batch was run on a glass mat; e.g.,
Vetrotex 2.10 Facer Mat, which weighed approximately
21-lbs/MSF.
[0090] Table 6 shows test data generated for thirty-five (35)
samples of the product of Example 6, which was produced by the
coating techniques of FIG. 2. For each sample, tensile test data
for the resultant coated glass mat is supplied in column 5 with
respect to the machine direction (M.D.), and in column 6 with
respect to the cross-machine direction (C.M.D.) dimension of the
glass mat. All tensile strength values provided in Table 6 (and in
Table 7) are in units of pounds per three inch wide strip of coated
glass mat ("pounds-per-3-linear-inches width"=lbs./3-L.I.). The
test method used is TAPPI T 1009 om-92, "Tensile strength and
elongation at break."
[0091] Included in the data of Table 6 are exceptionally low Cobb
Test numbers. The 2-minute Cobb Test used is TAPPI T 441 om-98
("Water absorptiveness of sized {non-bibulous} paper, paperboard,
and corrugated fiberboard {Cobb Test}."). The coated glass mat is
placed with the coated side up; e.g., under the water. Those
familiar with testing a mineral-pigment filled latex-bonded coating
may appreciate that a total water pick-up value of 0.025-grams is
extraordinarily low. By comparison, the coated glass mat utilizing
a common carboxylated SBR latex, such as BASF's Styrofan.RTM.
ND5406, obtained a 2-minute Cobb of 0.75-grams pick-up, on average.
Even utilizing a routine modified acrylic latex binder such as
BASF's Optive-600, the Cobb test data does not average less than
0.10-grams weight pick-up. Eventually, it was discovered that only
by utilizing modified acrylic latexes derived in part by using
various versatic acids can the superior water resistance be
achieved. Dow's NeoCAR-820 is such a latex. It is believed that no
other coating mixture previously known has the excellent water
resistance as the latex/filler technology taught in Example 6.
[0092] The CFM (Cubic Feet per Minute) porosity data such as that
shown in Table 6 are determined by using ASTM D 737-96, "Standard
Test Method for Air Permeability of Textile Fabrics."
Example 7
[0093] For Example 7 includes thirty-five samples using the same
batch of coating and the same fiber glass mat as of Example 6, but
using a RFS 5136-treated (e.g., coated) scored applicator roll 312
such as that of FIG. 7 in lieu of a smooth applicator roll, and
with the web's wrap angles being as in FIG. 6 (not as sharp as in
Example 6 and FIG. 2).
[0094] Concerning the data of Table 6 and Table 7, the sample size
tested was 3-inches wide by 10-inches long, with 1-inch at each end
inside the jaws, and the tensile test jaws were pulled at the speed
of 1-inch per minute. Those familiar with test results of uncoated
glass mat will note that the Standard Deviation is very similar to
the tensile test Sigma of plain glass mat. In other words, the wide
range of test scores for tensile testing are built into the glass
mat as produced, and coating the mat has no effect on that wide
range other than raise the individual numbers.
[0095] The discovery that a treated (e.g., coated) or scored
applicator roll (such as applicator roll 212 shown in FIG. 6 and
applicator roll 312 shown in FIG. 7) would provide the same benefit
as the sharper wrap angles of FIG. 2 provides substantial savings
in the costs of metal wear. More importantly, the relaxed wrap
angles of FIG. 6 and FIG. 7 allow the coater to run faster. At
least a ten percent (10%) increase in coater speed has been
achieved by reducing the sharp wrap angles of FIG. 2 to the relaxed
wrap angles of FIG. 6 or FIG. 7 (which are essentially the same
wrap angles as in FIG. 1).
[0096] The weights of the particular glass mat substrates described
in conjunction with the tensile strength enhancement examples
hereof are just examples. It should be understood that any glass
mat weighing more than 12.0-pounds per MSF, but preferably between
14.0-pounds per MSF and 30.0-pounds per MSF, may be used with the
new techniques herein disclosed. Inappropriate (e.g., lighter
weight) glass mats do not achieve the unusually high tensile
strengths that are obtained by adding less coating to heavier glass
mats. Appropriate weight glass mats are obtained from Saint-Gobain
Vetrotex America, Inc. and Johns Manville.
[0097] In view of the fact that the coated glass mats described
herein have more uniform penetration of coating into the glass mat,
the coating binds far more glass fibers together than the coating
of the prior art coated glass mat. The latex binder of the coating
is apparently better utilized, thus providing much higher tensile
strengths. More importantly, the coating binder spreads out more
uniformly to fill more glass fiber interstices, thereby enhancing
the strength.
[0098] The coated glass mat is advantageously employed in a
laminate product. By eliminating uncovered glass fibers in a
laminate product, essentially all of the coating meets up against
the core (e.g., Gypsum or polyiso foam insulation sandwiched
between the two coated glass mat facers). With essentially all of
the glass fibers having a contiguous covering of either coating or
core material, the cohesive strength of ordinary glass mats becomes
a mute point. The bonding strength between core material and the
coating is known to be good. The increased exposure of coating mix
to the glass mat substrates thus affords sufficient volume of
non-coated glass fibers to form an excellent bond with the gypsum
slurry. The substantial improvement in coated glass mat tensile
strength plus the excellent bond to the cured gypsum board creates
a high flexural test result, well above the minimum requirement of
the gypsum board product. The greater thickness of uncoated glass
mat proved to be detrimental in attempts to impregnate the
additional thickness with polyiso foam, for example.
[0099] The heavier weight glass mat was expected to pick up
correspondingly more coating weight. Manufacturing engineers had
anticipated a need to run the coaters substantially slower.
However, the heavier glass mat picked up a lower mass of coating
instead of a higher mass. It was discovered that while the coater
did need to run slower to accomplish complete dryness, the speed
reduction was not the magnitude expected.
[0100] Another benefit discovered when utilizing the lower density
(less coating mass covering more glass mat volume) coating was that
when used as a facer for gypsum its porosity was perfect. This
means it was dense enough to prevent gypsum slurry from
penetrating, yet not too dense to causes the facer to blow off from
escaping steam.
[0101] The enhanced tensile strength coated glass mat
advantageously has the ability to intertwine with a gypsum slurry
and to combine to produce a high flexural strength in a
three-dimensional board, made of gypsum or other core materials
such as thermoplastic or thermosetting plastics. The coated glass
mat or web also has good weather-proof characteristics, while at
the same time having excellent mold-growth resistance.
[0102] The enhanced tensile strength coated glass mat has enough
porosity to allow the gypsum to "breathe-out" water vapor while
still processing yet not allow gypsum slurry to leak through into
the processing machinery.
[0103] Thus, an improvement that was anticipated to be much more
costly and generally onerous to manufacture turned out to be only
slightly more costly and no more difficult to produce.
[0104] Further, the enhanced tensile strength coated glass mat has
enough fibers available to bond well with the cured gypsum, without
leaving too much glass fiber thickness such that the wet gypsum
slurry does not penetrate enough to cover all the loose fibers.
[0105] While providing the above mentioned desirable properties,
the coated glass mat/facer remains a low-cost product due, e.g., to
its using economy grade limestone in rich abundance and very little
of the high-cost polymer latexes.
[0106] While the invention has been described in connection with
what is presently considered to be the most practical and preferred
embodiment, it is to be understood that the invention is not to be
limited to the disclosed embodiment, but on the contrary, is
intended to cover various modifications and equivalent arrangements
included within the spirit and scope of the appended claims.
TABLE-US-00002 TABLE 1 Example 1 Example 1 Sample # M.D. C.M.D. 1
116 97 2 118 99 3 88 74 4 87 68 5 89 61 6 86 72 7 96 88 8 87 80 9
112 88 10 118 91 11 95 71 12 99 82 13 97 78 14 87 68 15 90 75 16 84
64 17 96 72 18 76 66 19 88 66 20 86 77 21 95 80 22 90 76 23 116 99
24 100 98 25 102 82 26 114 78 27 116 99 28 114 98 29 112 98 30 110
94 Average 98.8 81.3 Std. Dev. 12.6 12.2 Range 42.0 38.0
TABLE-US-00003 TABLE 2 Example 2 Example 2 Sample # M.D. C.M.D. 1
89 54 2 93 70 3 83 63 4 88 58 5 83 59 6 92 62 7 87 55 8 77 65 9 106
70 10 98 62 11 78 59 12 69 55 13 75 58 14 79 60 15 107 82 16 100 78
17 73 51 18 72 54 19 74 62 20 71 68 21 61 47 22 68 54 23 72 56 24
68 38 25 69 57 26 89 75 27 74 40 28 91 79 29 72 40 30 79 46 Average
81.2 59.2 Std. Dev. 11.9 11.2 Range 46.0 44.0
TABLE-US-00004 TABLE 3 Sample # Machine Direction Cross Mach. Dir.
1 101.6-lbs/3-inch 114.1-lbs/3-inch 2 113.5-lbs/3-inch
111.8-lbs/3-inch 3 140.2-lbs/3-inch 113.1-lbs/3-inch 4
116.9-lbs/3-inch 102.9-lbs/3-inch 5 120.5-lbs/3-inch
95.5-lbs/3-inch 6 110.9-lbs/3-inch 119.7-lbs/3-inch 7
111.5-lbs/3-inch 108.0-lbs/3-inch 8 129.3-lbs/3-inch
126.7-lbs/3-inch 9 159.8-lbs/3-inch 108.0-lbs/3-inch 10
141.8-lbs/3-inch 127.9-lbs/3-inch 11 135.5-lbs/3-inch
140.8-lbs/3-inch 12 130.5-lbs/3-inch 144.0-lbs/3-inch 13
83.5-lbs/3-inch 96.0-lbs/3-inch 14 113.8-lbs/3-inch
106.0-lbs/3-inch 15 112.5-lbs/3-inch 114.9-lbs/3-inch 16
134.5-lbs/3-inch 105.8-lbs/3-inch 17 126.8-lbs/3-inch
84.6-lbs/3-inch 18 141.7-lbs/3-inch 123.3-lbs/3-inch Average
123.6-lbs/3-inch 113.5-lbs/3-inch Std. Dev. 17.8 15.3
TABLE-US-00005 TABLE 4 Example 4 Tensile Data Sample # M.D. C.M.D.
1 122 110 2 114 108 3 141 113 4 117 103 5 121 96 6 123 120 7 112
108 8 129 125 9 150 108 10 141 127 11 135 120 12 130 138 13 130 121
14 134 101 15 128 114 16 134 105 17 126 97 18 141 98 19 121 100 20
143 128 21 140 98 22 110 98 23 121 109 24 146 105 25 148 110 26 138
106 27 135 97 28 141 104 29 138 102 30 143 104 Average 131.7 109.1
Std. Dev. 11.1 10.8 Range 40.0 42.0
TABLE-US-00006 TABLE 5 Sample # Machine Direction Cross Mach. Dir.
1 226.8-lbs/3-inch 214.0-lbs/3-inch 2 227.5-lbs/3-inch
184.4-lbs/3-inch 3 274.8-lbs/3-inch 167.5-lbs/3-inch 4
229.1-lbs/3-inch 168.4-lbs/3-inch 5 305.1-lbs/3-inch
176.1-lbs/3-inch 6 275.0-lbs/3-inch 174.2-lbs/3-inch 7
312.5-lbs/3-inch 176.1-lbs/3-inch 8 261.5-lbs/3-inch
267.5-lbs/3-inch 9 294.8-lbs/3-inch 256.5-lbs/3-inch 10
299.6-lbs/3-inch 210.9-lbs/3-inch Average 270.7-lbs/3-inch
199.6-lbs/3-inch Std. Dev. 33.3 36.8
TABLE-US-00007 TABLE 6 SHARP WRAP-ANGLE DATA Mat Wt. Wt. Tensile,
lbs./ lbs./ lbs./ Caliper 3-L.I. Cobb Roll No. MSF MSF inches MD
CMD CFM grams 1 21.5 90.3 0.032 165 168 7.38 0.034 2 20.8 95.6
0.032 185 142 4.27 0.043 3 22.1 84.1 0.033 148 156 7.49 0.037 4
22.1 88.9 0.033 182 177 8.26 0.046 5 21.8 89.3 0.033 178 138 6.18
0.042 6 21.8 87.2 0.032 175 138 9.58 0.012 7 21.4 91.1 0.032 182
154 6.73 0.033 8 21.4 87.5 0.031 131 153 6.60 0.020 9 22.0 86.0
0.032 145 109 5.48 0.017 10 22.0 91.6 0.032 160 158 4.68 0.032 11
21.1 84.8 0.030 167 158 4.41 0.026 12 21.0 92.2 0.031 171 187 1.46
0.023 13 21.0 89.1 0.032 182 106 4.74 0.028 14 21.7 84.2 0.030 167
102 2.67 0.028 15 21.0 92.8 0.031 190 152 3.30 0.018 16 20.9 88.1
0.030 165 136 3.76 0.014 17 20.9 86.3 0.030 151 148 2.28 0.018 18
21.1 89.1 0.032 173 143 1.73 0.016 19 21.0 85.0 0.031 156 166 2.43
0.017 20 21.5 93.7 0.031 167 157 4.39 0.033 21 21.5 84.0 0.031 156
148 3.33 0.017 22 21.9 83.7 0.031 149 138 3.42 0.020 23 21.1 91.8
0.032 169 169 3.85 0.022 24 21.1 88.3 0.030 158 180 2.67 0.042 25
21.6 87.0 0.030 155 140 2.29 0.031 26 21.3 89.4 0.031 173 160 3.83
0.024 27 21.8 85.2 0.031 150 103 2.05 0.016 28 21.2 87.2 0.031 163
145 5.25 0.025 29 21.6 90.6 0.032 179 165 2.33 0.019 30 21.4 89.7
0.033 146 143 3.97 0.016 31 22.2 89.4 0.033 132 112 2.47 0.022 32
22.2 84.8 0.032 142 130 3.27 0.013 33 21.6 93.9 0.030 198 147 1.37
0.016 34 21.0 88.4 0.032 159 136 1.22 0.028 35 21.4 82.3 0.031 145
111 2.59 0.031 AVG = 21.46 88.4 0.031 163.3 145.0 4.05 0.025 STDEV
0.42 3.3 0.001 16.1 21.9 2.09 0.009 RANGE 1.40 13.3 0.003 67.0 85.0
8.36 0.034
TABLE-US-00008 TABLE 7 COATED APPLICATOR ROLL DATA Mat Wt. Final
Wt. Tensile, lbs./ lbs./ lbs./ Caliper, 3-L.I. Porosity, Cobb, Roll
No. MSF MSF Inches MD CMD CFM Grams 1 21.1 93.3 0.034 174 166 7.38
0.059 2 21.0 88.8 0.032 158 150 4.62 0.031 3 21.0 83.2 0.030 174
159 6.62 0.030 4 21.4 81.9 0.030 171 161 4.61 0.039 5 21.4 86.4
0.030 154 111 9.77 0.026 6 20.7 88.9 0.031 158 164 5.45 0.038 7
20.7 85.4 0.032 171 175 5.13 0.038 8 22.1 86.6 0.031 174 145 5.35
0.085 9 22.1 92.8 0.032 159 137 8.79 0.027 10 21.0 88.2 0.031 183
141 7.85 0.025 11 21.7 87.7 0.032 170 112 1.93 0.012 12 21.7 87.7
0.031 200 141 9.27 0.029 13 22.2 92.1 0.032 188 144 6.50 0.026 14
21.5 96.6 0.030 184 154 6.43 0.025 15 21.6 92.9 0.030 170 172 7.65
0.021 16 21.4 89.3 0.030 164 161 3.01 0.024 17 21.4 94.0 0.031 196
158 2.19 0.023 18 21.4 90.5 0.030 193 161 2.50 0.029 19 21.0 89.7
0.032 148 176 6.07 0.019 20 21.0 93.1 0.030 159 138 3.01 0.021 21
21.3 89.6 0.028 177 145 1.71 0.010 22 21.4 95.7 0.031 178 186 1.82
0.018 23 21.4 83.7 0.030 152 154 2.78 0.018 24 21.4 90.5 0.030 170
145 6.05 0.030 25 20.6 89.0 0.031 172 157 2.83 0.016 26 20.6 93.2
0.030 182 144 1.79 0.026 27 21.1 92.1 0.031 174 150 2.86 0.020 28
21.1 81.8 0.030 176 152 4.01 0.020 29 21.1 94.1 0.033 197 154 8.52
0.033 30 22.0 79.5 0.031 154 142 6.30 0.010 31 22.0 90.4 0.031 181
148 6.11 0.020 32 23.0 86.8 0.031 188 123 9.90 0.034 33 22.3 78.1
0.030 159 133 3.44 0.008 34 22.3 88.8 0.031 176 148 6.43 0.014 35
21.6 84.5 0.030 166 143 5.60 0.020 AVG = 21.45 88.8 0.031 172.9
150.0 5.27 0.026 STDEV 0.55 4.5 0.001 13.4 16.2 2.46 0.014 RANGE
2.40 18.5 0.006 52.0 75.0 8.19 0.077
* * * * *