U.S. patent application number 09/845970 was filed with the patent office on 2002-12-26 for multicomponent mats of glass fibers and natural fibers and their method of manufacture.
Invention is credited to Dong, Daojie.
Application Number | 20020195216 09/845970 |
Document ID | / |
Family ID | 25296565 |
Filed Date | 2002-12-26 |
United States Patent
Application |
20020195216 |
Kind Code |
A1 |
Dong, Daojie |
December 26, 2002 |
Multicomponent mats of glass fibers and natural fibers and their
method of manufacture
Abstract
The invention relates to a method of forming a multicomponent
mat, the multicomponent mat which is formed from glass fibers and
natural fibers and methods of making a multicomponent mat.
Initially in the method of forming a multicomponent mat, a natural
fiber slurry is formed. The next step involves using a surfactant
to disperse glass fibers in white water. The natural fiber slurry
and the slurry of glass fibers are generally compatible and are
combined to form a multicomponent slurry which is used to form a
multicomponent mat.
Inventors: |
Dong, Daojie; (Westerville,
OH) |
Correspondence
Address: |
OWENS CORNING
2790 COLUMBUS ROAD
GRANVILLE
OH
43023
US
|
Family ID: |
25296565 |
Appl. No.: |
09/845970 |
Filed: |
April 30, 2001 |
Current U.S.
Class: |
162/145 ;
162/135; 162/149; 162/168.3; 162/171; 428/141 |
Current CPC
Class: |
D21H 11/12 20130101;
Y10T 428/24355 20150115; D21H 13/40 20130101; E04D 1/20
20130101 |
Class at
Publication: |
162/145 ;
162/149; 162/168.3; 162/171; 162/135; 428/141 |
International
Class: |
D21H 013/40; D21H
015/06; D21H 017/45; D21H 017/61; D21H 027/00 |
Claims
What is claimed is:
1. A method of making a multicomponent mat of glass fibers and
natural fibers comprising the steps of: (a) forming a natural fiber
slurry by mixing together natural fibers having a length between
about 5 mm and 51 mm and water; (b) forming a glass fiber slurry;
(c) combining and mixing the natural fiber slurry and the glass
fiber slurry; (d) forming a wet mat from the combined natural fiber
and glass slurries; and (e) removing any excess moisture.
2. The method of claim 1, wherein the natural fibers comprise at
least one of kenaf fibers and sisal fibers.
3. The method of claim 1, wherein the natural fiber slurry is
formed including a cationic polymer.
4. The method of claim 3, wherein the cationic polymer comprises an
acrylamide modified cationic polymer.
5. The method of claim 1, wherein the step of forming a glass fiber
slurry comprises the step of mixing together a dispersant, water,
glass fibers, and a viscosity modifier.
6. The method of claim 5, wherein the viscosity modifier comprises
a modified polyacrylamide.
7. The method of claim 5, wherein the surfactant comprises
cocamidopropyl hydroxysultaine.
8. The method of claim 5, wherein the glass fibers have an average
length of about 0.1 to about 1.5 inches.
9. The method of claim 5, wherein in the glass fiber slurry, the
glass fibers are present in an amount of about 0.1 to about 3.0
weight percent of the glass fiber slurry.
10. The method of claim 1, further comprising the steps of applying
a binder to the wet mat and curing the binder.
11. The method of claim 8, wherein the binder comprises a urea
formaldehyde binder.
12. The method of claim 1, wherein the viscosity of the slurry
mixture in step (c) is about 1.5 to about 6 centipoise.
13. A multicomponent mat formed by the method of claim 1.
14. The multicomponent mat of claim 13, wherein the glass fibers
are present in the mat in an amount ranging from about 10 to about
90 weight percent.
15. The multicomponent mat of claim 13, wherein the natural fibers
are present in the mat in an amount ranging from about 90 to about
10 weight percent.
16. The multicomponent mat of claim 13, wherein the mat further
includes a binder which is present in the mat in an amount ranging
from about 1 to about 30 weight percent.
17. The multicomponent mat of claim 13, wherein the glass fibers
are present in the mat in an amount ranging from about 10 to about
90 weight percent, the natural fibers are present in an amount
ranging from about 90 to about 10 weight percent.
18. A fiber slurry for making a multicomponent mat comprising: (a)
glass fibers having an average length of about 0.1 to about 1.5
inches; (b) natural fibers having a length between about 5 mm and
51 mm; and (c) water.
19. The fiber slurry of claim 18, wherein the glass fibers are
present in an amount of about 10 to about 90 weight percent of
total solids and the natural fibers are present in the amount of
about 90 to about 10 weight percent of total solids.
20. The fiber slurry of claim 18, further comprising (d) a
dispersant; and (e) a viscosity modifier.
21. The fiber slurry of claim 20, wherein the viscosity modifier
comprises a modified polyacrylamide.
22. A roofing shingle comprising: a multicomponent mat formed by
the process of: forming a natural fiber slurry by mixing together
natural fibers having a length between about 5 mm and 51 mm and
water; forming a glass fiber slurry; combining and mixing the
natural fiber slurry and the glass fiber slurry; forming a wet mat
from the combined natural fiber and glass slurries; applying a
binder to the wet mat; and removing any excess moisture and curing
the binder; and an asphalt coating on at least one outer surface of
the mat.
23. A roofing shingle as set forth in claim 22, wherein the natural
fibers comprise at least one of kenaf fibers and sisal fibers.
Description
TECHNICAL FIELD AND INDUSTRIAL APPLICABILITY OF THE INVENTION
[0001] This invention relates generally to multicomponent mats and
their method of manufacture. In particular, the invention relates
to a method of making a multicomponent mat of glass fibers and
natural fibers using a natural fiber slurry and a glass fiber
slurry and the mats formed by this method.
BACKGROUND OF THE INVENTION
[0002] U.S. Pat. Nos. 5,965,638 and 6,146,705 disclose structural
mat matrices comprising a substrate consisting essentially from 80%
to 99% by weight fiberglass fibers, from 20% to 1% by weight wood
pulp and from 5% to 15% by weight binder.
[0003] A method for making a bicomponent mat of glass fibers and
pulp fibers is disclosed in my copending application, U.S. Ser. No.
09/474,449, the disclosure of which is incorporated herein by
reference. The mat is formed from pulp and glass fibers. The pulp
fibers have a length of from about 0.05 inch to about 0.2 inch.
[0004] It would be desirable to form mats having natural fibers
with lengths that exceed the lengths of pulp fibers so as to
enhance the strength characteristics of the final mat.
SUMMARY OF THE INVENTION
[0005] Generally, the multicomponent mat of the present invention
is formed from glass fibers and natural fibers. The process
involves forming a natural fiber slurry comprising natural fibers
having a length between about 0.2 inch (5 mm) and about 2.0 inches
(51 mm) and water. The natural fiber slurry may include a cationic
polymer. The next step involves dispersing glass fibers in, for
example, a white water. The natural fiber slurry and the glass
fiber slurry are compatible with one another and are combined to
form a multicomponent furnish or slurry.
[0006] The mats of the present invention have several advantages.
First, they contain natural fibers which can be easily burned
during a disposal process once the useful life of a final product
in which a mat is incorporated has ended or can be easily recycled.
Second, the mats have high strength characteristics, especially
high tear strength. The mats of the present invention may be
incorporated into such products as shingles and automotive
headliners.
[0007] The method of this invention involves making a
multicomponent mat of glass fibers and natural fibers comprising
the steps of: forming a natural fiber slurry by mixing natural
fibers and water, a cationic polymer may or may not be added;
forming a slurry of glass fibers by mixing together a dispersant,
water, glass fibers, and a viscosity modifier; combining and mixing
the natural fiber slurry and the slurry of glass fibers to form a
wet mat; and removing any excess moisture. A binder may also be
applied to the wet mat. If applied, the binder may be cured during
the moisture removal step.
BRIEF DESCRIPTION OF THE DRAWINGS
[0008] FIG. 1 is a photocopy of a mat produced in Example 1;
[0009] FIG. 2 is a photocopy of a mat produced in Example 2;
[0010] FIG. 3 is a photocopy of a mat produced in Example 3;
[0011] FIG. 4 is a photocopy of a mat produced in Example 4;
[0012] FIG. 5 is a photocopy of a mat produced in Example 5;
[0013] FIG. 6 is a photocopy of a mat produced in Example 6;
[0014] FIG. 7 is a photocopy of a mat produced in Example 7;
[0015] FIG. 8 is a photocopy of a mat produced in Example 8;
[0016] FIG. 9 is a photocopy of a mat produced in Example 9;
[0017] Fig. 10 is a photocopy of a mat produced in Example 10;
[0018] FIG. 11 is a photocopy of a mat produced in Example 11;
[0019] FIG. 12 is a photocopy of a mat produced in Example 12;
[0020] FIG. 13 is a photocopy of a mat produced in Example 13;
[0021] FIG. 14 is a photocopy of a mat produced in Example 14;
[0022] FIG. 15 is a photocopy of a mat produced in Example 15;
[0023] FIG. 16 is a photocopy of a mat produced in Example 16;
[0024] FIG. 17 is a photocopy of a mat produced in Example 17;
and
[0025] FIG. 18 is a photograph of a mat produced in Example 18.
DETAILED DESCRIPTION AND PREFERRED EMBODIMENTS OF THE INVENTION
[0026] A multicomponent mat and method of forming such a mat is
described in detail below. Through the method of the invention
improved multicomponent mats may be formed which exhibit
advantageous properties as compared to conventional multicomponent
mats. The mats of the present invention preferably are formed from
natural fibers having a length between about 0.2 inch (5 mm) to
about 2.0 inches (51 mm), preferably in the range of about 0.25
inch (6.4 mm) to about 1.25 inch (31.8 mm), most preferably in the
range of about 0.5 inch (12.7 mm) to about 1.0 inch (25.4 mm), as
well as all other ranges subsumed within the range of 0.2 inch (5
mm) to about 2.0 inches (51 mm). Due to the length of the natural
fibers, the mats of the invention are capable of exhibiting
improved mechanical strength, tear resistance, and tensile
strength. The mats of the invention may be in the form of a uniform
web which may be coated with a binder composition depending upon
the desired use.
[0027] An objective of the disclosed method is to provide an
improved wet process method for making multicomponent mats of glass
fibers and natural fibers. The multicomponent mat may be formed by
handsheeting or pilot/commercial scale wet laid processes. A wet
laid process is advantageous for forming a generally uniform web,
and is particularly advantageous for obtaining a generally uniform
dispersion of fibers of different diameters.
[0028] The preferred article of the invention is a multicomponent
mat. The method of this invention involves making a multicomponent
mat of glass fibers and natural fibers comprising the steps of:
forming a natural fiber slurry by mixing together natural fibers
and water, a cationic polymer may or may not be provided; forming a
slurry of glass fibers by mixing together a dispersant, water,
glass fibers, and a viscosity modifier; combining and mixing the
natural fiber slurry and the slurry of glass fibers to form a wet
mat; and removing any excess moisture. A binder may be applied to
the wet mat. If so, the binder may be cured during the moisture
removal process.
[0029] The mat generally comprises two components: glass fibers and
natural fibers. An organic binder may also be provided. In the
finished mat, the glass fibers are present in the range of about
10% to about 90% by weight. The natural fibers are present in the
range of about 90% to about 10% by weight. The organic binder is
present in the range of about 0% to about 30% by weight, and
preferably in the range of about 5% to about 15%. Typically, the
mats of the invention will contain small amounts of a dispersant,
such as a surfactant. It is preferred that the mat contains less
than about 1% by weight of surfactant. The mat may have a thickness
of from about 0.010 inch to about 0.050 inch, and preferably from
about 0.015 inch to about 0.030 inch.
[0030] The invention involves the combination of a natural fiber
slurry and a glass fiber slurry. The first component of the
disclosed method comprises the natural fiber slurry. The preferred
natural fibers are kenaf fibers, sisal fibers, flax and hemp. Kenaf
fibers are commercially available from Kenaf Industries of
Raymondville, Tex. Commercially available kenaf fibers will
typically contain a small percentage of core and skin components.
It is preferred that such core and skin components comprise less
than 1% by weight of the kenaf fibers. Other natural fibers having
a length between about 0.2 inch (5 mm) and about 2.0 inches (51 mm)
may also be used.
[0031] One or two or more types of natural fibers may be employed
in making a given mat. For example, kenaf and sisal fibers, with or
without other natural fibers, may be employed. Alternatively, only
kenaf fibers or only sisal fibers may be used.
[0032] If the quality of the natural fibers is poor, i.e., they
contain an unacceptable amount (e.g., greater than 1% by weight of
the fibers) of core and skin components, then the fibers may
undergo a pretreatment process. Four such processes are discussed
in the Examples set out below. If such a pretreatment process is
deemed not necessary, the fibers will not be presoaked in
water.
[0033] The natural fibers of any moisture content are initially
added to water and subsequently agitated by a conventional blender
or mixer to form a slurry. The weight percentage of fibers in the
water is not particularly limited, so long as the fibers may be
dispersed in the water. For example, the natural fibers may
comprise between 2.0% and 20% by weight of the slurry, and
preferably about 7.0% to about 14% by weight of the slurry. A
cationic polymer may be added to treat the natural fiber slurry
should the natural fibers tend to flocculate or form clumps. With
many natural fibers, such a polymer is not required. If a cationic
polymer is used, the preferred cationic polymer is Nalco 7530,
which is an acrylamide modified cationic copolymer available from
Nalco Chemical Company, Naperville, Ill. The skilled artisan will
appreciate that several types of cationic polymers may be used.
When used, the weight percentage of cationic polymer added to the
natural fiber slurry may depend on the amount of natural fibers
used, the composition, charge density, and molecular weight of the
polymer used, as well as the size and type of container (e.g.
stainless steel or plastic) used in the process. Generally, the
polymer may comprise between 0% and 1.0% by weight of the slurry,
and preferably about 0.0% to about 0.5% by weight of the
slurry.
[0034] The term "white water" refers to an aqueous solution which
may contain numerous dispersants, thickeners, softening chemicals,
hardening chemicals, or dispersed or emulsified thermoplastic
polymers. The term "white water slurry" refers to an aqueous
solution comprising fibers dispersed in white water.
[0035] The glass fiber slurry preferably comprises a generally
uniform dispersion of the glass fibers in a water carrier medium or
white water. For example, the white water may comprise a system of
water, a dispersing agent (dispersant), and a viscosity modifier. A
viscosity modifier that increases the viscosity of the water
carrier medium will generally be selected and is referred to as a
thickener. A dispersant that beneficially aids fiber interaction
with the water carrier medium to assist in dispersion of the
separate fibers and acts to wet out the surface of the fibers, is
typically chosen. Also, pH adjustment of the water carrier medium
may be advantageous depending on the types of fibers. In addition,
it may be advisable in some cases to use a suitable anti-foaming
agent or other processing aids well known to those skilled in the
art.
[0036] Various ingredients may be used as the viscosity modifier
and dispersant, and it is not so important which additives are
chosen, but rather that a generally uniform dispersion of fibers in
the white water is produced. Also, the white water slurry will
advantageously be sufficiently stable that a web laid from the
white water slurry is generally uniform and free of aggregated or
clumped fibers.
[0037] According to the invention, a dispersant is added initially
to water. The dispersant is a surfactant that helps break bundles
and disperse glass filaments and natural fibers. The surfactant
assists in releasing the sizing agent typically present in
commercially available glass fibers. Selection will be based upon
compatibility with the different fiber components and with other
processing aids. The surfactant may be a cationic or amphoteric
surfactant. The preferred dispersants for the invention are, for
example, a cocamidopropyl hydroxysultaine, which is commercially
available from Rhone-Poulenc, under the product designation
"Mirataine CBS," and ethoxylated amine, which is commercially
available from Rhone-Poulenc, under the product designation
"Rhodameen VP-532/SPB. Another preferred dispersant includes an
ethoxylated amine, which is commercially available from Nalco
Chemical Co. under the product designation "Nalco 8493." The
dispersants may be deposited on and coat the glass and natural
fiber surfaces. This coating action may aid in deterring the
formation of clumps, tangles and bundles. This surfactant makes the
natural fiber slurry and the white water slurry compatible with
each other.
[0038] The concentration of the dispersant in the white water
slurry may be varied within relatively wide limits and may be as
low as 50 ppm of the white water slurry and up to as high as about
300 ppm. Higher concentrations up to about 500 ppm may be used but
may be uneconomical and cause low wet web strength. Thus, it is
preferred that the amount of the dispersant ranges from preferably,
about 50 ppm up to about 200 ppm.
[0039] It is believed that by adding the dispersant to an aqueous
medium first allows the glass fibers to enter a favorable aqueous
environment containing the dispersant which is immediately
conducive to their maintaining their individuality with respect to
each other whereby there is substantially no tendency to flocculate
or form clumps, tangles or bundles. By employing the dispersing
agents of the invention, the glass fibers are dispersed to arrive
at the conditions of nonflocculation.
[0040] After the dispersant is added to the aqueous mixture, glass
fibers are added. The glass fibers are chosen from the group
consisting of glass fibers, rock wool and other suitable mineral
fibers. Of these fibers, the preferred material is chopped glass
fibers such as fibers commercially available from Owens Coming,
Toledo, OH, sold under the product designations "OC 9502 Wet Use
Chopped Strands," "OC 776B Wet Use Chopped Strands," and "OC 9501
Wet Use Chopped Strands." Glass fibers do not absorb any moisture,
have high tensile strengths, very high densities and excellent
dimensional stability. The glass fibers suitable for use in the
invention have average lengths of from about 0.1 inch to 1.5 inch,
preferably 0.75 inch to 1.25 inch and have an average diameter in
the range of 5 to 30 microns, preferably 10 to 20 microns, and most
preferably, 11 to 16 microns. These commercially available fibers
are characteristically sized. Sizes are commonly employed by
manufacturers of glass fibers and the release of the sizing
composition by a cationic antistatic agent eliminates fiber
agglomeration and permits a uniform dispersion of the glass fibers
upon agitation of the dispersion in the tank. The typical amount of
glass fibers for effective dispersion in the glass slurry (a thick
stock) is within the range of 0.1 percent to about 3.0 percent, and
most preferably about 1 percent, by weight of the dispersion or
white water slurry. Thereafter, the white water slurry or thick
stock is diluted and prior to forming the mat, the amount of glass
fibers is between about 0.01% and 0.1%, preferably, about 0.02% to
about 0.06%, and most preferably, about 0.03% to about 0.05% by
weight of the white water slurry.
[0041] After the glass fibers have been added and mixed, a
viscosity modifier is added to the aqueous solution. The viscosity
modifier acts to increase the viscosity of the water carrier medium
and also acts as a lubricant for the fibers. Through these actions,
the viscosity modifier acts to combat flocculation of the fibers.
The concentration of the viscosity modifier in the white water
slurry may likewise be varied within relatively wide limits.
Concentrations may be from about 50 ppm to about 1,000 ppm of the
white water slurry, or in some cases as much as about 1%.
[0042] Any viscosity modifier that achieves a viscosity in the
range of 1.5 to 6.0 centipoise in the white water slurry may be
used. Preferably, the viscosity modifier may achieve a viscosity in
the range of 2.0 to 4.0 centipoise, and most preferably, in the
range of 3.0 to 3.5. Useful viscosity modifiers also include
synthetic, long chain, linear molecules having an extremely high
molecular weight, on the order of at least about 1 million and up
to about 15 million, or 20 million, or even higher. Preferably,
molecules with a molecular weight of 16 million are used. Examples
of such viscosity modifiers are polyethylene oxide which is a long
chain, nonionic homopolymer and has an average molecular weight of
from about 1 to 7 million or higher; polyacrylamide which is a
long, straight chain, nonionic or slightly anionic homopolymer and
has an average molecular weight of from about 1 million up to about
15 million or higher; acrylamide-acrylic acid copolymers which are
long, straight chain, anionic polyelectrolytes in neutral and
alkaline solutions, but nonionic under acid conditions, and possess
an average molecular weight in the range of about 2 to 3 million,
or higher; and polyamines which are long, straight chain, cationic
polyelectrolytes and have a high molecular weight of from about 1
to 5 million or higher. The preferred viscosity modifiers include
modified polyacrylamides available from Nalco Chemical Company,
such as Nalco 2824 and Nalco 7768.
[0043] Other useful viscosity modifiers include nonionic
associative thickeners, for example, relatively low
(10,000-200,000) molecular weight, ethylene oxide-based, urethane
block copolymers. These associative viscosity modifiers are
particularly effective when the fiber slurry contains 10% or more
staple length hydrophobic fibers. Commercial formulations of these
copolymers are sold by Rohm and Haas, Philadelphia, Pa., under the
trade names ACRYSOL RM-825 and ACRYSOL RHEOLOGY MODIFIER QR-708,
QR-735, and QR-1001 which comprise urethane block copolymers in
carrier fluids. ACRYSOL RM-825 is 25% solids grade of polymer in a
mixture of 25% butyl carbitol (a diethylene glycol monobutylether)
and 75% water, and ACRYSOL RHEOLOGY MODIFIER QR-708, a 35% solids
grade in a mixture of 60% propylene glycol and 40% water can also
be used. Similar copolymers in this class, including those marketed
by Union Carbide Corporation, Danbury, Conn. under the trade names
SCT-200 and SCT-275 and by Hi-Tek Polymers under the trade name SCN
11909 are useful in the process of this invention.
[0044] Another class of suitable viscosity modifiers, preferred for
making up fiber furnishes containing predominantly cellulose
fibers, e.g. rayon fibers or a blend of wood fibers and synthetic
cellulosic fibers such as rayon, comprises the modified nonionic
cellulose ethers of the type disclosed in U.S. Pat. No. 4,228,277
incorporated herein by reference in its entirety. Such cellulosic
ethers are sold under the trade name AQUALON by Hercules Inc.,
Wilmington, Del. AQUALON WSP M-1017, and include a hydroxy ethyl
cellulose modified with a C-10 to C-24 side chain alkyl group and
having a molecular weight in the range of 50,000 to 400,000 that
may be used in the whitewater system.
[0045] Other viscosity modifiers suitable for use in the invention
are available under the trade designations Hyperfloc CP 905 L,
Hyperflock CE 193, Hyperfloc AE 847, and Hyperflock AF 307, all
commercially available from Hychem, Inc., Tampa, Fla.; Superfloc MX
60, Magrifloc 1885 A, Superflock A 1885 and Cytec AF124,
commercially available from Cytec Industries, West Paterson, N.J.,
and Jayflock 3455 L, commercially available from Callaway Chemical
Company, Columbus, Ga.
[0046] A conventional defoamer may be used in the white water to
prevent the buildup of foam during the forming process.
[0047] After the glass fiber slurry is formed, it is combined with
the natural fiber slurry to form a thick stock or furnish. The
thick stock is then diluted by combining between about 15 to about
30 parts white water with about 1 part thick stock. The diluted
thick stock is referred to as a thin stock. The thin stock is then
placed on a screen in a known manner and precipitated into a
nonwoven, sheet-like mat by the removal of water, usually by a
suction and/or vacuum device to form a wet mat. In the wet mat,
natural fibers are present in an amount of about 90 to about 10
weight % of total solids, the glass fibers are present in an amount
of about 10 to about 90 weight % of total solids, and the
dispersant is present in the wet mat in an amount of about 1 weight
% or less of total solids. The mat is dried at a temperature to
remove the moisture.
[0048] A mat binder, such as any conventional thermoplastic or
thermoset binder, may be applied to the wet mat. Suitable binders
include poly(vinyl alcohol), poly(vinyl acetate), carboxymethyl
cellulose and starch, SBR modified urea formaldehyde (UF) resin,
and styrene butadiene latex. The binder is present in the wet mat
in an amount of about 0 to about 30 weight percent of total solids
and preferably from about 5% to about 15%.
[0049] Having applied a binder to the mat, the drying and curing of
the mat may be done by any well-known means of drying water in the
mat and heating it. For example, the mat may be heat cured. One
known drying machine is a Honeycomb System Through-Air Dryer. The
heating temperature may be from 190.degree. C. to 260.degree. C. It
is to be appreciated that too high a temperature will damage the
multicomponent mat and too low a temperature will either result in
a curing time that is too excessive (if a thermoset binder is used)
or inadequate melting of a thermoplastic binding composition (if a
thermoplastic binder is used).
[0050] An example of a suitable heating process includes passing
the mat through a drying machine in which the mat is dried and the
resin is cured, e.g. thermoset or chemically bonded. Generally the
resin may be a modified UF resin with SBR.
[0051] When drying and bonding the mat having a thermoplastic
binder, the melting temperature of the thermoplastic binder may
vary. Selection of a relatively higher drier temperature generally
requires a relatively shorter exposure time, whereas selection of a
relatively lower drier temperature usually requires a relatively
longer exposure time.
[0052] The multicomponent mats of the invention may be made using
conventional equipment in a batch, semi-batch, or a continuous
process. For example, in a small batch process, the multicomponent
mat may be formed by draining off water from the furnish by use of
a deckle box, and the multicomponent fibers may be caught on the
top of the screen of the deckle box. The wet multicomponent fiber
mat may be dried to form a handsheet.
[0053] For a commercial scale process, the multicomponent mats of
the invention are generally processed through the use of
papermaking-type machines such as commercially available
Fourdrinier, wire cylinder, Stevens Former, Roto Former, Inver
Former, Venti Former, and inclined Delta Former machines.
Preferably, an inclined Delta Former machine is utilized. A
multicomponent mat of the invention can be prepared by forming
natural fiber and glass fiber slurries and combining the slurries
in mixing tanks, for example. The amount of water used in the
process may vary depending upon the size of the equipment used.
Typical volumes of water range from about 300,000 liters to about
1,850,000 liters. The thick stock may be delivered into a silo
where the thick stock is diluted to form a thin stock or furnish.
The furnish may be passed into a conventional head box where it is
dewatered and deposited onto a moving wire screen where it is
dewatered by suction or vacuum to form a non-woven multicomponent
web. The web can then be coated with a binder by conventional
means, e.g., by a flood and extract method and passed through a
drying oven which dries the mat and cures the binder. The resulting
mat may be collected in a large roll.
[0054] The foregoing detailed description has been given for
clearness of understanding only and no unnecessary limitations
should be understood therefrom as modifications will be obvious to
those skilled in the art.
[0055] While the invention has been described in connection with
specific embodiments thereof, it will be understood that it is
capable of further modifications and this application is intended
to cover any variations, uses, or adaptations of the invention
following, in general, the principles of the invention and
including such departures from the present disclosure as come with
known or customary practice within the art to which the invention
pertains and as may be applied to the essential features
hereinbefore set forth and as follows in scope of the appended
claims.
[0056] The invention will be described in greater detail in the
following examples wherein there are disclosed various embodiments
of the present invention for purposes of illustration, but not for
purposes of limitation of the broader aspects of the present
inventive concept.
EXAMPLES 1-18
[0057] In Examples 1-18, multicomponent handsheets of glass and
natural fibers having dimensions of about 12 inches.times.12 inches
were formed. The handsheets had a thickness (not including the
thickness of a binder layer if provided) of between about 0.015
inch and 0.035 inch. The handsheets in Examples 1-18 resulted from
benchtop experiments. A photocopy of a section of each resultant
handsheet is set out in FIGS. 1-18. A conventional office-photocopy
machine was used to generate the photocopies, i.e., the mats were
placed on the glass-scanning surface of a photocopying machine to
generate the photocopies.
[0058] Initially, Kenaf fibers, purchased form Kenaf Industries of
Raymondville, Tex., were pretreated as the fibers were of poor
quality, i.e., the fibers had an unacceptable amount of core and
skin components. Two separate pretreatment processes were used,
Pretreatment Process D and Pretreatment Process A.
Pretreatment Process D
[0059] Pretreatment Process D involved filling a hydropulper with
20 gallons of water and 12 milliliters (mL) of Nalco 7530 (obtained
from Nalco, Naperville, Ill.). The contents in the hydropulper were
mixed for about 30 seconds. Then, 800 grams of kenaf fiber
(previously chopped to lengths of about 1 inch using a portable
chopper) were added to the hydropulper and pulped for 60 minutes.
Subsequently, the slurry was filtered and the natural fibers were
collected on a screen. The collected fibers were washed several
times using water and core and skin components were manually
removed. Thereafter, the wet fibers were pressed to squeeze off
excess water, and left on a tabletop to air dry to a moisture
content of about 15%. The pretreated natural fibers were labeled as
"D fibers."
Pretreatment Process A
[0060] Pretreatment Process A involves the same steps as
Pretreatment D except Nalco 7530 was not added. Fibers pretreated
using Pretreatment Process A were labeled "A Fibers."
EXAMPLE 1
[0061] A natural fiber slurry was first prepared in a small food
blender. 200 mL of city water, 2.1 grams of "D Fibers" having a
moisture content of about 15%, and 10 drops of Nalco 7530 were
added to the food blender. The contents were mixed (blended) at a
medium speed for about 2 minutes. The natural fiber slurry was then
ready for use.
[0062] A glass fiber slurry was prepared in a stainless steel
container. The glass fibers used were purchased from Owens Corning
under the product designation "OC 9502 Wet Use Chopped Strands."
The fibers had a diameter of about 16 microns and a length of about
1 inch. Immediately after the glass fiber slurry was formed, the
natural fiber slurry was combined with the glass fiber slurry.
[0063] To form the glass fiber slurry, 5 liters of water, and 12
drops of a cocamidopropyl hydroxysultaine, functioning as a
dispersant, and acquired from Rhone Poulenc under the product
designation "Mirataine CBS" were added to the container. Agitation
and a timer were then initiated. At about 10 seconds after the
start of the timer, about 5.5 grams of the OC 9502 1-inch fibers
were added to the container under agitation. At about 1 minute
after the start of the timer, about 150 mL of pre-diluted Nalco
7768 (about 0.5% by weight Nalco 7768 and 99.5% by weight water),
obtained from Nalco Company, Naperville, Ill., and serving as a
viscosity modifier, were added to the container under agitation.
The glass fiber slurry was then ready to receive the natural fiber
slurry.
[0064] At about 2 minutes after the start of the timer, the natural
fiber slurry was added to the container under agitation. Agitation
of the contents continued for about 12 minutes after the start of
the timer. The mixed glass and natural fiber slurry was then ready
for use in making a handsheet.
[0065] Prior to forming a handsheet, a deckle box was filled with
about 35 liters of water and about 60 mL of pre-diluted Nalco 7768
(about 0.5% by weight Nalco 7768 and 99.5% by weight water). The
contents in the deckle box were slightly mixed using a conventional
mixing element. The glass and natural fiber slurry was then poured
into the deckle box. To effect mixture of the contents now in the
deckle box, the contents were stroked about 5 times using a
conventional mixing element. Water was then drained from the deckle
box and the remaining fibers were collected on a screen to form a
handsheet. The resultant glass and natural fiber handsheet had
sufficient structural integrity and strength such that the fibers
remained joined together after the handsheet was removed from the
deckle box even though no binder was used. A photocopy of a section
of the handsheet is set out in FIG. 1.
EXAMPLE 2
[0066] A handsheet was formed using the same process set out in
Example 1 except that 2.1 grams of "A Fibers" were used in forming
the natural fiber slurry. The resultant glass and natural fiber
handsheet had sufficient structural integrity and strength such
that the fibers remained joined together after the handsheet was
removed from the deckle box even though no binder was used. A
photocopy of a section of the handsheet is set out in FIG. 2.
EXAMPLE 3
[0067] A handsheet was formed using the same process set out in
Example 1 except that 2.1 grams of "A Fibers" were used in forming
the natural fiber slurry. Further, no amount of Nalco 7530 was
added to the natural fiber slurry. The resultant glass and natural
fiber handsheet had sufficient structural integrity and strength
such that the fibers remained joined together after the handsheet
was removed from the deckle box even though no binder was used. A
photocopy of a section of the handsheet is set out in FIG. 3.
EXAMPLE 4
[0068] A handsheet was formed using the same process set out in
Example 1 except that 4.0 grams (instead of 2.1 grams) of "D
Fibers" were used in forming the natural fiber slurry, and 3.0
grams (instead of 5.5 grams) of glass fibers were used in forming
the glass fiber slurry. Further, the 10 drops of Nalco 7530 were
not added to the natural fiber slurry. However, 12 mL of Nalco 7530
were still used in the pretreatment process. The resultant glass
and natural fiber handsheet had sufficient structural integrity and
strength such that the fibers remained joined together after the
handsheet was removed from the deckle box even though no binder was
used. A photocopy of a section of the handsheet is set out in FIG.
4.
EXAMPLE 5
[0069] A handsheet was formed using the same process set out in
Example 1 except that 0.5 grams (instead of 2.1 grams) of "D
Fibers" were used in forming the natural fiber slurry, and 6.5
grams (instead of 5.5 grams) of glass fibers were used in forming
the glass fiber slurry. Further, the 10 drops of Nalco 7530 were
not added to the natural fiber slurry. However, 12 mL of Nalco 7530
were still used in the pretreatment process. A photocopy of a
section of the handsheet is set out in FIG. 5.
EXAMPLE 6
[0070] A handsheet was formed using the same process set out in
Example 1 except that 6.0 grams (instead of 2.1 grams) of "D
Fibers" were used in forming the natural fiber slurry and 1.0 gram
(instead of 5.5 grams) of glass fibers were used in forming the
glass fiber slurry. Further, the 10 drops of Nalco 7530 were not
added to the natural fiber slurry. However, 12 mL of Nalco 7530
were still used in the pretreatment process. The resultant glass
and natural fiber handsheet had sufficient structural integrity and
strength such that the fibers remained joined together after the
handsheet was removed from the deckle box even though no binder was
used. A photocopy of a section of the handsheet is set out in FIG.
6.
EXAMPLE 7
Different Dispersant
[0071] A handsheet was formed using the same process set out in
Example 1 except that 12 drops of Rhodameen VP-532/SPB, acquired
from Rhone-Poulenc, were used as the dispersant (instead of
Mirataine CBS) in the glass fiber slurry. The resultant glass and
natural fiber handsheet had sufficient structural integrity and
strength such that the fibers remained joined together after the
handsheet was removed from the deckle box even though no binder was
used. A photocopy of a section of the handsheet is set out in FIG.
7.
EXAMPLE 8
Single Component Handsheet
[0072] A handsheet was formed using the same process set out in
Example 1 except that 7.0 grams (instead of 2.1 grams) of "D
Fibers" were used in forming the natural fiber slurry and 0.0 grams
(instead of 5.5 grams) of glass fibers were used in forming the
glass fiber slurry. Further, the 10 drops of Nalco 7530 were not
added to the natural fiber slurry. However, 12 mL of Nalco 7530
were still used in the pretreatment process. The resultant natural
fiber handsheet (it included no glass fibers) had sufficient
structural integrity and strength such that the fibers remained
joined together after the handsheet was removed from the deckle box
even though no binder was used. A photocopy of a section of the
handsheet is set out in FIG. 8.
EXAMPLE 9
1/2 Inch Kenaf Fiber
[0073] A handsheet was formed using the same process set out in
Example 2 except that 3.0 grams of 1 inch long "A Fibers" (instead
of 2.1 grams of 1 inch "A Fibers") were used in the natural fiber
slurry, and 5.0 grams (instead of 5.5 grams) of OC 9502 glass
fibers were used in the glass fiber slurry. The resultant glass and
natural fiber handsheet had sufficient structural integrity and
strength such that the fibers remained joined together after the
handsheet was removed from the deckle box even though no binder was
used. A photocopy of a section of the handsheet is set out in FIG.
9.
EXAMPLE 10
11 Micron, 1/4 Inch Glass Fibers
[0074] A handsheet was formed using the same process set out in
Example 2 except that 5.5 grams of glass fibers having a diameter
of 11 microns and a length of about 1/4 inch were used. Such fibers
are commercially available from Owens Coming under the product
designation "OC 776B WUCS." A photocopy of a section of the
handsheet is set out in FIG. 10.
EXAMPLE 11
11/4 Inch Glass Fibers
[0075] A handsheet was formed using the same process set out in
Example 2 except that 5.5 grams of glass fibers having a diameter
of 16 microns and a length of about 11/4 inches were used. Such
fibers are commercially available from Owens Coming under the
product designation "OC 9502 WUCS." The resultant glass and natural
fiber handsheet had sufficient structural integrity and strength
such that the fibers remained joined together after the handsheet
was removed from the deckle box even though no binder was used. A
photocopy of a section of the handsheet is set out in FIG. 11.
EXAMPLE 12
With a Binder
[0076] A handsheet was formed using the same process set out in
Example 1. Thereafter, a binder mixture comprising about 95% by
weight urea formaldehyde (obtained from Borden Chemical, Inc. of
Columbus, Ohio under the product designation "Bordon 485") and
about 5% by weight styrene butadiene latex (obtained form Dow
Chemical under the product designation "490NA") was impregnated
into the handsheet. Excess binder was removed via vacuum. The
coated handsheet was then dried and cured in a convection oven at
175.degree. C. for 15 minutes. A photocopy of a section of the
handsheet after application of the binder is set out in FIG.
12.
EXAMPLE 13
With a Binder
[0077] A handsheet was formed using the same process set out in
Example 1 except that the glass fibers, commercially available from
Owens Coming under the product designation "OC 9501 WUCS" (having a
different sizing chemistry), were used. The binder mixture set out
in Example 12 was impregnated into the handsheet. The coated
handsheet was then dried and cured in a convection oven at
175.degree. C. for 15 minutes. A photocopy of a section of the
resultant handsheet after application of the binder is shown in
FIG. 13.
EXAMPLE 14
Bicomponent Handsheet of Sisal and Glass Fibers
[0078] A natural fiber slurry was first prepared in a small food
blender. 200 mL of city water and about 2.1 grams of sisal fibers
were added to the blender. The sisal fibers had a moisture content
of about 3%. Furthermore, the sisal fibers were prechopped to
lengths of about 1.5 inches. The contents in the blender were mixed
(blended) at a medium speed for about 2 minutes. The natural fiber
slurry was then ready for use.
[0079] A glass fiber slurry was formed using the same process set
out in Example 1 except that 5.0 grams (instead of 5.5 grams) of
glass fibers were used in forming the glass fiber slurry. The sisal
fiber slurry was then combined with the glass fiber slurry and a
handsheet was formed from the combined slurry using the deckle box
process set out in Example 1. A photocopy of a section of the
resultant handsheet is shown in FIG. 14.
EXAMPLE 15
Bicomponent Handsheet of Sisal and Glass Fibers
[0080] A handsheet was formed using the same process set out in
Example 14 except that the sisal fibers were prechopped to a
lengths of about 1 inch. A photocopy of a section of the resultant
handsheet is shown in FIG. 15.
EXAMPLE 16
Bicomponent Handsheet of Sisal and Glass Fibers
[0081] A handsheet was formed using the same process set out in
Example 15 except that the sisal fibers were prechopped to lengths
of about 0.5 inch, and 3.0 grams (rather than 2.1 grams) of sisal
fibers were used in forming the natural fiber slurry. Further, 4.0
grams (instead of 5.0 grams) of OC 9502 glass fibers were used in
the glass fiber slurry. A photocopy of a section of the resultant
handsheet is shown in FIG. 16.
EXAMPLE 17
Tricomponent Handsheet of Glass Kenaf and Sisal Fibers and Binder
Coating
[0082] A natural fiber slurry was first prepared in a small food
blender. 200 mL of city water, 2.0 grams of "A Fibers" having a
moisture content of about 15% by weight and 2.0 grams of sisal
fibers having a moisture content of about 3% by weight and
prechopped to lengths of about 1/4 inch, were added to a food
blender. The contents were mixed (blended) at a medium speed for 2
minutes. The natural fiber slurry was then ready for use.
[0083] A glass fiber slurry was formed using the same process set
out in Example 1 except that 3.0 grams (instead of 5.5 grams) of
glass fibers were used in forming the glass fiber slurry. The sisal
and kenaf fiber slurry was then combined with the glass fiber
slurry and a handsheet was formed from the combined slurry using
the deckle box process set out in Example 1.
[0084] After the handsheet was formed, a binder mixture comprising
about 95% by weight urea formaldehyde (obtained from Borden
Chemical, Inc.) and about 5% by weight styrene butadiene latex
(obtained form Dow Chemical) was impregnated into the handsheet.
Excess binder was removed via vacuum. The coated handsheet was then
dried and cured in a convection oven at 175.degree. C. for 15
minutes. A photocopy of a section of the handsheet is shown in FIG.
17.
EXAMPLE 18
Tricomponent of Glass, Kenaf and Sisal Fibers with a Binder
[0085] A handsheet was formed using the same process set out in
Example 17 except that the natural fiber slurry was made
differently. It comprised 200 mL of city water, 2.0 grams of "A
Fibers" having a moisture content of about 15% by weight, 2.0 grams
of sisal fibers having a moisture content of about 3% by weight and
prechopped to lengths of about 1/4 inch, and about 10 drops of
Nalco 7530. Those contents were added to a food blender and mixed
(blended) at a medium speed for about 2 minutes. The natural fiber
slurry was then ready for use.
[0086] A glass fiber slurry was formed using the same process set
out in Example 17. The sisal and kenaf fiber slurry was then
combined with the glass fiber slurry and a handsheet was formed
from the combined slurry using the deckle box process set out in
Example 1.
[0087] The binder mixture set out in Example 17 was subsequently
impregnated into the handsheet. The coated handsheet was then dried
and cured in a convection oven at 175.degree. C. for 15 minutes. A
photocopy of a section of the resultant handsheet is shown in FIG.
18.
EXAMPLES 19-25
[0088] Initially, Kenaf fibers, purchased form Kenaf Industries of
Raymondville, Tex., were pretreated as the fibers were of poor
quality, i.e., the fibers had an unacceptable amount of core and
skin components. Two separate pretreatment processes were used,
Pretreatment Process D1 and Pretreatment Process A1.
Pretreatment Process D1
[0089] Pretreatment Process D1 involved filling a hydropulper with
30 gallons of water and 25 milliliters (mL) of Nalco 7530 (obtained
from Nalco, Naperville, Ill.). The contents in the hydropulper were
mixed for about 30 seconds. Then, 4 pounds of kenaf fiber
(previously chopped to lengths of about 1 inch using a portable
chopper) were added to the hydropulper and pulped for 70 minutes.
Subsequently, the slurry was filtered and the natural fibers were
collected on a screen. The collected fibers were washed several
times using water and core and skin components were manually
removed. Thereafter, the wet fibers were pressed to squeeze off
excess water, and had a moisture content between about 60% and
about 80%. The pretreated natural fibers were labeled as "D1
fibers."
Pretreatment Process A1
[0090] Pretreatment Process A1 involves the same steps as
Pretreatment D1 except Nalco 7530 was not used. Fibers pretreated
using Pretreatment Process A1 were labeled "A1 Fibers."
[0091] In each of Examples 19-25, the natural fibers had a length
of about 1 inch; the glass fibers had a diameter of about 16
microns, a length of about 1 inch and were purchased from Owens
Corning under the product designation "OC 9502 Wet Use Chopped
Strands"; the dispersant used in the glass fiber slurry was
Mirataine CBS; the viscosity modifier used in the glass fiber
slurry was Nalco 7768; and, if a cationic polymer was provided in
the natural fiber slurry, Nalco 7530 was used.
Preparation of White Water
[0092] White water was prepared by mixing 100 mL of Mirataine CBS
and 600 mL Nalco 7768 with 1500 gallons of city water. This fresh
white water was stored in a white water tank and aged for at least
24 hours before being used in a mat making process.
[0093] The continuous length mats of Examples 19-25 were made using
a conventional 30-inch wide pilot scale wet process line under the
conditions set out in Table 1.
1TABLE 1 Pilot Wet Process Line Parameters for Example 19 to 25.
Nalco 7768, 600 mL CBS, 100 mL Dispersant = Mirataine CBS;
Viscosity Modifier = Nalco 7768 Fiber Viscosity Nalco 7530 Glass
Natural grams Dispersant modifier mL in N.F. MAT Compositon Final
Run # gram (wet) type (wet) mL mL Slurry glass/N.F./Binder Note
Example 19 00-5-1 6500 None 0 20 20 none 80.5/0.0/18.5 Control
Example 20 00-5-2 6500 None 0 20 20 none 80.9/0.0/19.1 Control
Example 21 00-5-3 6130 A1 900 30 20 none 78.0/3.7/18.3 Example 22
00-5-9 5850 A1 1260 80 100 300 78.0/5.1/16.9 Example 23 00-5-10
5850 D1 1260 80 100 300 78.1/4.9/17.0 Example 24 00-5-12 5200 A1
3800 80 100 300 72.4/9.8/17.8 Example 25 00-5-17 4680 D1 11000 80
100 400 73.1/26.9/0.0 No binder
[0094] For Examples 21-25, a natural fiber slurry was prepared by
adding natural fibers, in an amount specified in Table I, and about
25 gallons of white water to a hydropulper. "Wet" in Table 1
indicates that the natural fibers had a moisture content of from
about 60% to about 80% prior to being added to the hydropulper. The
contents were then mixed for 3 to 5 minutes in the hydropulper. A
specified amount of Nalco 7530, as indicated in Table 1, was added
in Examples 22-25 only.
[0095] The glass fiber slurry was prepared in a 500-gallon tank for
each of Examples 19-25. About 400 gals of white water, mixed and
aged as set out above, and an amount of dispersant, as specified in
Table I, were added to and mixed in the tank. Then, a quantity of
glass fibers, as specified in Table I, was added to the tank. A
timer was also started when the glass fibers were added. At 3
minutes after the start of the timer, about 20 gallons of diluted
viscosity modifier solution, comprising a mixture of 20 gallons of
white water and an amount of Nalco 7768 (viscosity modifier), as
specified in Table I, was pumped into the tank. The glass fiber
slurry was then completed.
[0096] At about 5 minutes after the start of the timer, the
prepared natural fiber slurry was added to the glass fiber slurry
in the tank, Examples 21-25 only. Additional white water was added
to the tank so that the combined volume of the mixture was 500
gallons. The contents of the 500-gallon tank were agitated for
another 5 minutes before being ready for use in forming a mat. A
small amount of an antifoam agent was also added if excess foam was
observed.
[0097] When the mixed natural and glass fiber slurry was ready, it
was pumped into a headbox where excess water was drained off by
means of both gravity and vacuum, and the fibers were deposited on
an endless moving screen. A continuous mat was formed on the moving
screen at a given line speed. The wet mat then passed under a
flood-and-extract curtain coater where it was coated with an
aqueous binder. The excess binder was removed by vacuum.
Thereafter, the coated mat was dried and the binder cured in a
oven. The dried mat was wound up into a roll.
[0098] The mats of Examples 19 and 20 did not contain any natural
fibers and were control examples to which the remaining mats of
Examples 21-25 were compared. In Example 21, the natural fiber
slurry contained only 900 grams of wet natural fibers and contained
no amount of Nalco 7530. The glass fiber slurry in Example 21
contained only 30 mL of dispersant and 20 mL of viscosity modifier.
The glass fiber slurries in Examples 22-25 contained 80 mL of
dispersant and 100 mL of viscosity modifier. The mat of Example 25
did not receive a binder coating. However, the multicomponent mat
of Example 25 had sufficient strength that it could be wound into a
roll.
2TABLE 2 Mat Property (raw data) for Examples 19 to 24. MD CMD MD
CMD SAMPLE Basis Tensile Tensile Elmundorf Tear Elmundorf Tear
Number Weight (lbs/2 in) (lbs/2 in) grams grams Total tensile Total
tear Ignition Loss % Example 19 00-5-1 0.019 67.2 56.8 419.9 467.9
124.0 887.7 18.5 Example 20 00-5-2 0.019 66.2 53.2 375.3 469.7
119.4 845.1 19.1 Example 21 00-5-3 0.017 49.7 39.7 381.9 398.3 89.4
780.1 22.0 Example 22 00-5-9 0.016 61.7 41.2 462.4 348.3 102.9
810.7 22.0 Example 23 00-5-10 0.016 69.9 47.0 326.0 415.1 116.8
741.1 21.9 Example 24 00-5-12 0.014 50.8 32.8 311.5 421.9 83.6
733.3 27.6 Binder + Natural Fiber
[0099]
3TABLE 3 CORRECTED MAT PROPERTY (corrected for the mat basis weight
only, with a reference basis weight = 0.017 pounds/sq ft) MD CMD MD
CMD SAMPLE Basis Tensile Tensile Elmundorf Tear Elmundorf Tear
Number Weight (lbs/2 in) (lbs/2 in) grams grams Total tensile Total
tear Example 19 00-5-1 0.019 60.1 50.8 375.7 418.6 110.9 794.3
Example 20 00-5-2 0.019 59.2 47.6 335.8 420.3 106.8 756.1 Example
21 00-5-3 0.017 49.7 39.7 381.9 398.3 89.4 780.1 Example 22 00-5-9
0.016 65.6 43.7 491.3 370.0 109.3 861.3 Example 23 00-5-10 0.016
74.2 49.9 346.4 441.0 124.1 787.4 Example 24 00-5-12 0.014 61.7
39.8 378.2 512.3 101.5 890.5
[0100] Mat property data for the mats of Examples 19-24 are set out
above in Tables 2 and 3. The basis weight is in units of
pounds/ft.sup.2. "MD Tensile" designates the tensile strength of a
2-inch strip cut from the corresponding mat in the machine
direction of the mat, i.e., the strip had a longitudinal axis
extending parallel to the machine direction of the mat. "CMD
Tensile" designates the tensile strength of a 2-inch strip cut from
the corresponding mat in a cross machine direction of the mat,
i.e., the strip's longitudinal axis ran 90.degree. to the machine
direction of the mat. "MD Elmundorf Tear" is the tear strength of a
2-inch strip cut from the corresponding mat having a longitudinal
axis extending parallel to the machine direction of the mat. "CMD
Elmundorf Tear" is the tear strength of a 2-inch strip cut from the
corresponding mat having a longitudinal axis extending 90.degree.
to the machine direction of the mat. "Total Tensile" is the
summation of "MD Tensile" and "CMD Tensile." "Total Tear" is the
summation of "MD Elmundorf Tear" and "CMD Elmundorf Tear."
[0101] In Table 3, the data was corrected for mat basis weight
only, such that all data for each example was adjusted to
correspond to a reference basis weight of 0.017 pounds/ft.sup.2. As
is apparent from Table 3, the total tear strength for each of the
mats of Examples 22 and 24 was greater than the corresponding total
tear strength of the mats of control Examples 19 and 20. Hence, the
tear strength of the mats of Examples 22 and 24, which mats
included both glass and natural fibers, exceeded that of the
control mats, which included only glass fibers.
EXAMPLES 26-31
[0102] Examples 26-31 are directed to asphalt shingles. The mats
set out in Examples 19-24 were used in the forming processes of the
shingles of Examples 26-31 respectively.
[0103] All of the asphalt shingles of Examples 26-31 were made
under similar conditions. Initially, the mats of Examples 19 to 24
were slit into 12-inch wide sections. During separate passes
through a conventional lab-made asphalt coater, those sections were
coated on opposing sides with a calcite filled hot asphalt. The
asphalt was acquired from Owens Corning, under the product
designation "SU#7696-01." The calcite was acquired from Imery's
Pigments and Additives, Roswell Ga. The calcite filled asphalt
comprised by weight 65% calcite and 35% asphalt.
[0104] Prior to the strip passing through the coater, the filled
asphalt was preheated to a temperature of about 425.degree. F. A
doctor blade, incorporated into the coater, was used to control the
coating thickness. It was set at 0.065 inch relative to a datum
such that all six samples received a coating and the combined
thickness of the sample and the coating was 0.065 inch. After the
first pass through the coater, the coated side of the strip was
dusted with sand. Then, the asphalt coating was allowed to cool as
the strip moved through cold rollers. Subsequently, the strip was
wound up into a roll.
[0105] During the second pass through the coater, the asphalt was
coated on a second side of the mat, then dusted with sand. The
parameters in the second pass were exactly the same as in the first
pass, except that the doctor blade was set at 0.095 inch from the
datum such that the strip received a coating and the combined
thickness of the strip and the two coatings was 0.095 inch.
4TABLE 4 Shingle Property (Raw data) For Examples 26 to 31. MD CMD
Mat # Used Mat MD Tensile Elmundorf Tear Elmundorf Tear Total Tear
in Shingle Basis Weight Pounds grams grams Grams Example 26 00-5-1
0.019 208.3 1693.4 1963.9 3657.3 Example 27 00-5-2 0.019 192.2
1643.9 1936.3 3580.2 Example 28 00-5-3 0.017 155.5 1900.0 2113.4
4013.4 Example 29 00-5-9 0.016 172.5 1680.1 2281.5 3961.6 Example
30 00-5-10 0.016 182.1 1699.3 2304.3 4003.6 Example 31 00-5-12
0.014 149.9 1788.7 1823.1 3611.8
[0106]
5TABLE 5 CORRECTED SHINGLE PROPERTY (corrected for the mat basis
weight only, with a reference basis weight = 0.017 pounds/sq ft) MD
CMD Mat # Used Mat MD Tensile Elmundorf Tear Elmundorf Tear Total
Tear in Shingle Basis Weight Pounds grams grams Grams Example 26
00-5-1 0.019 190.4 1547.7 1795.0 3342.7 Example 27 00-5-2 0.019
176.6 1510.6 1779.3 3289.9 Example 28 00-5-3 0.017 157.4 1922.6
2138.6 4061.2 Example 29 00-5-9 0.016 183.3 1785.1 2424.1 4209.2
Example 30 00-5-10 0.016 198.4 1851.8 2511.1 4362.9 Example 31
00-5-12 0.014 175.7 2097.1 2137.4 4234.5
[0107] Shingle property data for the shingles of Examples 26-31 are
set out in Tables 4 and 5. The basis weight is in units of
pounds/ft.sup.2. "MD Tensile" designates the tensile strength of a
2-inch strip cut from the corresponding shingle in the longitudinal
direction of the shingle, i.e., the strip had a longitudinal axis
extending parallel to the longitudinal axis of the shingle. "MD
Ehmundorf Tear" is the tear strength of a 2-inch strip cut from the
corresponding shingle and having a longitudinal axis extending
parallel to the longitudinal axis of the shingle. "CMD Elmundorf
Tear" is the tear strength of a 2-inch strip cut from the
corresponding shingle and having a longitudinal axis extending
90.degree. to the longitudinal axis of the shingle. "Total Tear" is
the summation of "MD Elmundorf Tear" and "CMD Elmundorf Tear."
[0108] In Table 5, the data was corrected for mat basis weight
only, such that all data for each example was adjusted to
correspond to a reference basis weight of 0.017 pounds/ft.sup.2. As
is apparent from Table 5, the total tear strength for each shingle
of Examples 28-31 was greater than the corresponding total tear
strength of the shingles of control Examples 26 and 27. Hence, the
tear strength of the shingles of Examples 28-31, which shingles
included both glass and natural fibers, exceeded that of the
control shingles, which included only glass fibers.
* * * * *