Note: Descriptions are shown in the official language in which they were submitted.
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FDN-2989
FIBER MAT AND PROCESS FOR MAKING SAME
BACKGROUND OF THE INVENTION
1. Field of the Invention
The present invention relates generally to a fiber mat and a process of
making the same, and, more particularly, to a glass fiber mat comprising
fibers, a binder and a defined binder modifier. Embodiments of the present
invention can have desired characteristics, such as, for example, improved
wet web strength and dry mat tensile strengths, and hot wet tensile retention,
and improved shingle tensile and shingle tear strengths, as compared with a
conventional mat where no such defined binder modifier is employed, and can
be suitable for use in building materials.
2. Description of the Prior Art
High strength fiber mats are increasingly used in the building materials
industry, most commonly in roofing shingles. Fiber mats have numerous
other material applications, including use in roofing, siding and floor
underlayment; insulation facers; floor and ceiling tile; and vehicle parts.
Various fiber mats and methods of making the same have been
described previously. For example, U.S. Patent Nos. 4,135,029; 4,258,098;
5,914,365; and 6,642,299, describe glass fiber mats made by a wet-laid
process formed from glass fibers held together by a binder material.
Typically, in wet processed glass fiber mats, the binder is applied in liquid
form and dispersed onto the glass fibers by an applicator. Conventional wet
processes strive to produce a uniform coating of binder on the glass fibers.
After the binder and glass fibers have been dried and cured, the glass fiber
mat is cut as desired.
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A major problem in the manufacturing process and use of some known
fiber mats is inadequate wet web strength. The wet web strength of wet glass
mat has significant impact on glass mat production and mat properties. In
order to prevent the mat web from breaking during production, the speed of
the production line has to be adjusted (reduced) to the low wet web strength
of the wet glass mat before curing. Also, a lower wet web strength requires a
higher vacuum drawing to support the wet web and to minimize web breaking.
However, a higher vacuum drawing will lead to an undesired mat properties,
for example, a high mat tensile ratio.
Inadequate dry mat tensile strengths also can reduce the ability of the
finished roofing product to resist stresses during service on the roof.
Because
building materials, generally, and roofing shingles, in particular, are often
subjected to a variety of weather conditions, the fiber mats should also
maintain their strength characteristics under a wide range of conventional
conditions.
SUMMARY OF THE INVENTION
Responsive to the foregoing challenges, an improved fiber mat for use
in a building materials component has been developed. In one embodiment,
the invention fiber mat includes a plurality of fibers; a resinous fiber
binder, the
fibers being fixedly distributed in the binder; and a binder modifier which is
a
functional silane monomer or polymer. By "fixedly distributed", it is meant
chemically bonded with binder. The binder modifier comprises 0.1 wt.% to 50
wt.%, based on the weight of the binder.
The present invention also relates to a binder composition which
includes a blend of a resinous fiber binder and a binder modifier which is a
functional silane monomer or polymer.
In addition to the above, the present invention also provides a process
for making an improved fiber mat. In one embodiment, the process comprises
the steps of: forming an aqueous fiber slurry; removing water from the fiber
slurry to form a wet fiber mat; saturating the wet fiber mat with an aqueous
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solution of a fiber binder and binder modifier, and forming, via drying and
curing, a fiber mat product from the wet fiber mat.
The fiber mats in accordance with the embodiments of the present
invention are particularly suitable for use as a component of building
materials. In addition, the process of making fiber mats in accordance with
the embodiments of the present invention can provide an improved wet web
strength to an uncured mat as well as improved dry mat tensile strengths.
In this invention, the glass mats made from resin binder and the
functional silane monomer or polymer binder modifier exhibits improved wet
web strength, and dry mat tensile strengths; improved hot wet tensile
retention. Also roofing shingles made from such mats have improved shingle
and tear strengths.
Additional advantages of embodiments of the present invention are set
forth, in part, in the description which follows and, in part, will be
apparent to
one of ordinary skill in the art from the description and/or from the practice
of
the invention.
DETAILED DESCRIPTION OF THE INVENTION
As stated above, the fiber mat of the present invention comprises a
plurality of fibers fixedly distributed in a fixative composition. The
fixative
composition comprises 0.05 wt.% to 45 wt.% of fiber binder, based on the
weight of the fiber mat product, and 0.1 wt.% to 50 wt.% of the binder
modifier
based on the binder weight.
The functional silane monomer or polymer which is the binder modifier
of the invention contains a functional group which can couple with the
resinous fiber binder material. Suitable functional silanes include amino
silanes, vinyl silanes, methacryloxy silanes, mercaptosilanes, and epoxy
silanes.
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Examples of such functional silane monomers and polymers thereof,
include gamma-aminopropyltrialkoxysilanes, gamma-isocyanatopropyl-
triethoxysilane, vinyl-trialkoxysilanes, glycidoxypropyltrialkoxysilanes and
ureidopropyltrialkoxysilanes, such as A-187 gamma-glycidoxy-
propyltrimethoxysilanes, A-174 gamma-methacryloxypropyltrimethoxysilane,
A-1100 gamma-aminopropyl-triethoxysilane, A-1108 amino silane and A-1160
gamma-ureidopropyl-triethoxysilane (each of which are commercially
available from OSi Specialties, Inc. of Tarrytown, N.Y.).
Amino siiane, monomers and polymers have been found to be
particularly effective binder modifiers, e.g. trimethoxysilylpropyldiethylene-
triamine, N-methylaminopropyltrimethoxysilane,
aminoethylaminopropylmethyldimethoxysilane,
aminoethylaminopropyltrimethoxysilane (Dow Coming Z-6020), a
homopolymer of an amino silane (Dow Corning Z-6137),
aminopropylmethyldimethoxysilane, aminopropyltrimethoxysilane, polymeric
aminoalkylsilicone, aminoethylaminoethylaminopropyl-trimethoxysilane,
N-methylaminopropyltrimethoxysilane, methylamino-propyltrimethoxysilane,
aminopropylmethyldimethoxysilane, aminopropyltriethoxysilane,
4-aminobutyltriethoxysilane, and oligomeric aminoalkylsilane and the like,
which are available from Dow Coming, Midland, Mich., Union Carbide
Specialty Chemicals Division, Danbury Connecticut and Huls of America,
Piscataway, N.J., Wacker Silicones Corporation of Adrian, Mich.
In one embodiment of the present invention, the fiber binder comprises
a formaldehyde type resin. The fiber binder can include, but is not limited
to,
a urea/formaldehyde resin, a phenol/formaldehyde resin, a
melamine/formaldehyde resin, and/or a mixture thereof. It is contemplated,
however, that other binders, such as, for example, ethylene vinyl acetate, and
other known resins adapted for binding mat fibers, can be used without
departing from the scope and spirit of the present invention.
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In one embodiment of the present invention, the urea-formaldehyde
resin is a commercially available material, such as, for example, GP2997
supplied by Georgia Pacific Resins, Inc.; Dynea~ 246 from Dynea Co.; and
Borden FG~ 486D and Borden 607A; from Borden Chemical Inc. Other
commercial formaldehyde resins, such as, for example, S-3701-C supplied by
Pacific Resins and Chemicals, Inc.; and PR-913-23, supplied by Borden
Chemical, Inc.; may be used as well. As will be apparent to those of ordinary
skill in the art, other commercially or non-commercially available binders can
be used without departing from the scope and spirit of the present invention.
In one embodiment of the present invention, the resinous fiber binder
can contain methylol groups which, upon curing, form methylene or ether
linkages. These methylols can include, for example, N,N'-dimethylol;
dihydroxymethylolethylene; N,N'-bis(methoxymethyl), N,N'-dimethylol-
propylene; 5,5-dimethyl-N,N'-dimethylolpropylene; N,N'-dimethylolethylene;
N,N'-dimethylolethylene and the like.
In one embodiment, the weight ratio of resinous fiber binder to
functional silane monomer or polymer binder modifier is 200:1 to 4:1. In one
embodiment of the present invention, the weight ratio is more particularly
99:1
to 9:1.
The fiber binder and binder modifier are adapted to be compatible.
These components can be intimately admixed in an aqueous medium to form
a stable emulsion which does not become overly gummy, or gel, even after
prolonged storage, e.g., for a period of a year or longer. This stability
factor is
advantageous in commercial use of the invention composition.
In one embodiment of the present invention, the fibers comprise glass
fibers. The glass fibers can comprise individual fiber filaments having an
average length in the range of, but not limited to: from about'/ inch to about
3
inches, and an average diameter in the range of, but not limited to: from
about
1 to about 50 microns (N). It is contemplated, however, that the glass fibers
can be in another form, such as, for example, a continuous strand or strands.
In an alternative embodiment of the present invention, the fibers can comprise
other fibers, including, but not limited to: wood, polyethylene, polyester,
nylon,
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polyacrylonitrile, and/or a mixture of glass and one or more of the other
fibers.
In one embodiment, the fiber mat can further comprise a small amount of
filler, e.g., less than about 0.5%, based on the fiber weight. A fiber mixture
can be optional for construction material applications, such as, for example,
roofing and siding, because an excessive amount of filler can reduce porosity
and vapor ventability of the fiber mat.
In the finished cured mat product, the fiber content can be in the range
from about 55 wt.% to about 98 wt.%. In one embodiment of the present
invention, the fiber content is more particularly in the range from about 70
wt.% to about 85 wt.%.
The fiber mat in accordance with one embodiment of the present
invention can further comprise a fiber dispersing agent for dispersing the
plurality of fibers in the fixative composition. The fiber dispersing agent
can
comprise, for example, tertiary amine oxides (e.g., N-hexadecyl-N,N-dimethyl
amine oxide, bis(2-hydroxyethyl) tallow amine oxide, dimethyl hydrogenated
tallow amine oxide, dimethylstearyl amine oxide and the like, and/or mixtures
thereof). As will be apparent to those of ordinary skill in the art, other
known
dispersing agents can be used without departing from the scope and spirit of
the present invention. The dispersing agent can be used in a concentration in
the range from about 10 ppm to about 8,000 ppm, based on the amount of
fiber, preferably 200 ppm to 1,000 ppm.
In one embodiment, the fiber mat can further comprise one or more
viscosity modifiers to increase the viscosity of the binder and/or the
fixative
composition such that the settling time of the fibers is reduced and the
fibers
can be adequately dispersed. The viscosity modifier can include, but is not
limited to, hydroxyl ethyl cellulose (HEC), polyacrylamide (PAA), and the
like.
As will be apparent to those of ordinary skill in the art, other viscosity
modifiers can be used without departing from the scope and spirit of the
present invention.
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The fiber fixative composition employed herein can be prepared by
blending the binder and binder modifier in water, under agitation, until a
uniform mixture is obtained. The resulting aqueous mixture can then be used
to saturate the wet mat of dispersed fibers, after which the excess mixture
can
be removed before drying and curing at an elevated temperature.
Alternatively, an aqueous mixture of the binder alone can be prepared and
applied to the wet mat of dispersed fibers, in which case the binder modifier
can be separately and subsequently applied by spraying, dipping or other
means. In still another alternative embodiment, all or a portion of the binder
modifier can be applied over the mat after initiation of the drying and/or
curing
process.
The process of making a fiber mat in accordance with one embodiment
of the present invention will now be described with particular reference to a
wet-laid process. It is contemplated, however, that other processes known in
the art, such as, for example, a dry-laid process, can be used without
departing from the scope and spirit of the present invention. Furthermore, the
process is described using chopped bundles of glass fibers. As discussed
above, however, other types of fiber content are considered well within the
scope of the present invention.
The process of forming glass fiber mats according to one embodiment
of the present invention comprises adding chopped bundles of glass fibers of
suitable length and diameter to a water/dispersant agent medium to form an
aqueous fiber slurry. A viscosity modifier or other process aid can optionally
be added to the water/dispersant agent medium. For example, about 0.05 to
about 0.5 wt.% viscosity modifier in white water can be suitably added to the
dispersant to form the slurry.
The glass fibers can be sized or unsized, and can be wet or dry, as
long as they are capable of being suitably dispersed in the water/dispersant
agent medium. The fiber slurry, containing from about 0.03 wt.% to about 8
wt.°l° solids, is then agitated to form a workable dispersion at
a suitable and
uniform consistency. The fiber slurry can be additionally diluted with water
to
a Power fiber concentration to between about 0.02 wt.% and about 0.08 wt.%.
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In one embodiment, the fiber concentration can be more particularly diluted to
about 0.04 wt.% fiber. The fiber slurry is then passed to a mat-forming
machine such as a wire screen or fabric for drainage of excess water. Then
excess water can be removed with the assistance of vacuum.
The fibers of the slurry are deposited on the wire screen and drained to
form a wet fiber mat. The wet mat is then saturated by soaking in an aqueous
solution of the binder or binder modifier fixative composition. The aqueous
solution can comprise, for example, from about 10 wt.% to about 40 wt.%
solid. The wet mat can be soaked for a period of time sufficient to provide
the
desired fixative for the fibers. Excess aqueous binder or binder/modifier
composition is then removed, preferably under vacuum.
After treatment with binder or binder/modifier composition, if desired,
the mat is then dried and the fixative composition is cured in an oven at an
elevated temperature (greater than about 150°C). A temperature in the
range
of about 160°C to about 350°C, for at least about 2 to 10
seconds, is typically
used for curing. In one embodiment, a cure temperature in the range of about
225°C to about 300°C is used. In an alternative embodiment of
the present
invention, it is contemplated that catalytic curing can be provided with an
acid
catalyst, such as, for example, ammonium chloride, p-toluene sulfonic acid, or
other suitable catalyst. As discussed above, any amount of binder modifier
not included with the binder solution can be applied to the drained fiber
slurry,
the drained mat containing binder, and/or the cured product. The binder
modifier can be applied as a spray and/or as a bath as an aqueous solution.
The combination of the binder and binder modifier used in various
embodiments of the present invention provides several advantages over
current binder compositions, particularly with respect to wet web strength,
dry
mat tensile strength, hot wet tensile retention and shingle tensile and tear
strengths.
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Having generally described various embodiments of the present
invention, reference is now made to the following examples which illustrate
embodiments of the present invention and comparisons to a control sample.
The following examples serve to illustrate, but are not to be construed as
limiting to, the scope of the invention, as set forth in the appended claims.
Preuaration of Glass Mat
Part A. In a 20 liter vessel at room temperature, under constant
agitation, 5.16 g of chopped bundles of glass fibers, having an average 20-40
mm length and 12-20 micron diameter, were dispersed in 12 liters of water
containing 800 ppm of N-hexadecyl-N,N-dimethylamine oxide to produce a
uniform aqueous slurry of 0.04 wt.% fibers. The fiber slurry was then passed
onto a wire mesh support with dewatering fabric, and a vacuum was applied
to remove excess water and to obtain a wet mat containing about 60% fibers.
Part B. Aqueous samples of 19 wt.% solids containing
urea/formaldehyde resin binder (UF) and aminosilane monomer (Dow Corning
Z-6020) or aminosilane homopolymer (Dow Corning Z-6137) as binder
modifier were separately prepared and applied to individual samples of wet
glass mats prepared by the procedure of Part A. The individual wet mats then
were soaked in the binder/modifier solutions under ambient conditions after
which excess solution was removed under vacuum to provide binder/modifier
wet mats containing 40.5 wt.% glass fibers, 9.5 wt.% binder/modifier and 50
wt.% water.
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Part C. For comparison purposes, Control samples were prepared as
described in Parts A and B except that the OF binder was used alone or with
OmnovaGenflo3112 latex, a carboxylated styrene-butadiene copolymer latex.
Part D. The wet web strength of the above uncured wet mats was
measured in the following way. The uncured wet mat was laid over a sheet of
plastic with a hole in the center. Then weights were continuously added to the
center of the mat to elongate the uncured mat to a defined distance. The final
weight was recorded as the wet web strength of the uncured mat.
Part E. The mat samples made according to Parts A and B were dried
and cured for 8 to 9 seconds at 270°C to 300°C to obtain dry
glass mats
weighing about 92 g/m2 and having a Loss on Ignition (LOI) of about 19%.
Part F. Each of the above cured mat samples were passed to a two-
roller coating machine where a 30 mil layer of 32 wt.% asphalt and 68 wt.%
limestone filler was applied at 420°F to each side of the mat. After
cooling,
the thus-filled asphalt coated mats were cut into 1 x 9 inch shingle specimens
and their tensile strengths measured on an Instron~ Tensile Machine at room
temperature or below. The results of these tests are given in Tables 1 to 2
below.
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TABLE 1
Compositions
Ingredient Control-1 Invention
Exam le A
OF Binder GP2997 GP2997
Binder ModifierNone Z-6137
Modifier Homopolymer
of
Chemistry None an Amino-
functional Silane
UF:Modifier 100 99/1
(w/w)
Mat and Shingle
Properties
Invention
Property Control-1 Invention Example A os.
Example A Control-1 (
/o
Increase
na
eb 226 275 +22%
Stren th
Mat Tensile 239 271 +13%
N/50 mm
Hot Wet% * 40 63 +58%
Shingle Tensile1256 1477 +18%
si
* The hot wet% or hot wet tensile retention % of a cured glass mat was
measured in the following way. A 2" x 8" glass mat strip was soaked in a
80°C. water bath for 10 minutes. Excess water on the mat strip was
dried by
pressing the strip against a piece of paper towel. The mat tensile was tested
in an Instron~ Tensile Machine. Hot wet % was calculated as mat tensile
strength after hot water soaking/mat tensile strength before soaking x 100%.
The results show a significant increase in the wet web strength, mat
tensile, hot wet and shingle tensile strengths for Invention Example A over
the
Control-1 sample.
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TABLE 2
Comaositions
Ingredient Control-2 Invention Invention
Exam le B Exam le C
Binder Borden 607A Borden 607A Borden 607A
Binder ModifierOmnovaGenflo3112 Dow Corning Dow Corning
Z-6137 Z-6020
Carboxylated Homopolymer Monomer of
Modifier
Styrene-Butadieneof Amino piaminofunctional
Chemistry F
Copolymer unctional Silane
Silane
Binder:Modifier
99/1 99/1 99/1
w/w
Mat and Shingle Properties
Control-2Invention B vs. InventionC vs.
Example Control Example Control
B
C
Mat Tensile
N/50 mm 213 297 +39% 273 +28%
Shingle
Tear 1197 1356 +13% 1295 +8%
The results show a significant increase in mat tensile and shingle tear
strengths for Invention Examples B and C over the Control-2 sample.
It will be apparent to those skilled in the art that variations and
modifications of the present invention can be made without departing from the
scope or spirit of the invention. For example, embodiments of the fiber mat
can be used in a building material including, but not limited to:
underlayment,
insulation facers, floor and ceiling tile, vehicle parts, and or any other
suitable
building material. Thus, it is intended that the present invention cover all
such
modifications and variations of the invention, provided the modifications and
vibrations come within the scope of the appended claims and their
equivalents.
