Note: Descriptions are shown in the official language in which they were submitted.
2048g38
METHOD FOR MAKING INSULATION
This invention relates to insulation and methods for
producing the same.
More particularly, the invention relates to a method
and apparatus for producing a low density thermal insulation
batt which includes insulative fibers having a low denier
and which includes binder fibers which have been softened to
adhere to and interconnect insulative fibers in the batt.
In another respect, the invention relates to a method
and apparatus for producing a thermal insulation batt of
insulative fibers which also includes short stilt fibers
which interconnect and space apart the insulative fibers to
define interstitial air pockets intermediate the insulative
fibers.
U. S. Patent No. 4,678,822 to Lewellin describes a
method for producing a bonded fiber insulation batt. In the
Lewellin method, a carding machine is utilized to form a
web. The web passes through a lapping machine which folds
the web onto itself to form a batt. While the web is being
lapped into batt form, a RHOPLEX resin emulsion is sprayed
onto the web. The batt formed by the lapping machine is
heated to dry the resin emulsion. The resin sprayed on the
batt is important, because Lewellin relies on the resin to
ensure the batt retains its bulk and structural integrity.
In his patent, Lewellin notes that two advantages of an
insulation batt produced by his method are that the batt
does not present the health hazard of fiberglass batts and
that the batt occupies a lesser space than fiberglass batts.
Finally, Lewellin notes that the insulative value of his
batt is equal to that of a fiberglass batt. The density of
the Lewellin batt is about 1.5 lbs/ft. The resin increases
the density of the Lewellin batt.
While the insulation batt described in the Lewellin
patent has advantages over conventional fiberglass batts,
Lewellin does not address the problem of producing a low
density insulation batt which does not require the use of a
resin spray to bond together insulative fibers in the batt.
Reducing the density of an insulation batt and eliminating
the use of a resin spray significantly reduces the cost of
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producing and utilizing the batt. A low density insulation
batt requires less material in manufacture and costs less to
transport.
Accordingly, it would be highly desirable to provide an
improved low density insulation batt which would not require
the use of conventional spray resins to bond together
insulative fibers comprising the batt.
Therefore, it is a principal object of the invention to
provide an improved method and apparatus for producing
insulation and to provide an improved insulation batt.
A further object of the invention is to provide an
improved insulation batt which has a significantly lower
density than conventional batts.
Another object of the instant invention is to provide
an improved method for producing an insulative batt, the
method not requiring the utilization oE spray apparatus to
apply a resin to the batt to bind together insulative fibers
comprising the batt.
Still another object of the invention is to provide an
improved insulation composition which utilizes relatively
short stilt fibers to interconnect and space apart
insùlative fibers to maintain interstitial air pockets
thereinbetween.
Yet still a further object of the invention is to
provide an improved insulation composition which includes
binder fibers which have a softening temperature less than
the melting temperature of the insulative fibers comprising
the majority of the batt, the insulation batt being heated
to a temperature greater than the softening temperature and
less than the melting temperature to soften the binder
fibers and cause them to adhere to and interconnect
insulative fibers.
These and other, further and more specific objects and
advantages of the invention will be apparent to those
skilled in the art from the following detailed description
thereof, taken in conjunction with the drawings, in which;
Fig. l is a flow diagram depicting a method of
manufacture of an insulation batt in accordance with the
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2~89~
principles of the invention;
Fig. 2 is a flow diagram depicting a method of
manufacture of an insulation batt in accordance with an
alternate embodiment of the invention; and,
Figs. 3 and 4 illustrate still another alternate
embodiment of the invention.
Briefly, in accordance with my invention, I provide a
method for forming a thermal insulation batt. The method
includes the steps of blending at a first selected
temperature binder fibers with insulative fibers, the binder
fibers having a bonding temperature at which the binder
fibers soften and adhere to the insulative fibers, the
insulative fibers being selected from the group consisting
of synthetic and natural fibers and having a melting
temperature greater than the bonding temperature and at
which at least certain of the insulative fibers melt, the
bonding temperature being greater than 130F and greater
than the first selected blending temperature; processing the
blended fibers at a second selected temperature less than
the bonding temperature to form a batt; heating the batt to
a temperature equal to or greater than the bonding
temperature and less than the melting temperature to cause
the binder fibers to soften and adhere to the insulative
fibers to connect insulative fibers to one another; and,
cooling the batt to harden the softened binder fibers.
In another embodiment of my invention, I provide an
improved method for forming a thermal insulation batt. The
method includes the steps of processing at a first selected
temperature insulative fibers to form a web having a
selected thickness, the insulative fibers being selected
from the group consisting-of synthetic and natural fibers
and having a melting temperature at which at least certain
of the insulative fibers melt, the melting temperature being
greater than the first selected temperature; transporting at
a second selected temperature the web to a lapping machine
to be lapped into a batt having a thickness greater than the
web; lapping at a third selected temperature the web with
the lapping machine to form a batt having a greater
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thickness than the web; transporting at a fourth selected
temperature the batt from the lapping machine to apparatus
for heating the batt to a temperature greater than or equal
to a selected softening temperature and less than said
melting temperature; applying binder fibers to said web
during at least one of the process steps selected from the
group consisting of steps (b), (c), and (d), the binder
fibers softening and adhering to the insulative fibers at
the selected softening temperature, the softening
temperature being greater than 130F, less than the melting
temperature, and greater than the selected temperature for
the one(s) of the steps (b), (c), and (d) during which the
binder fibers are applied to the web at the selected
temperature for the one(s) of the steps (b), (c), and (d);
heating the batt with the heating apparatus to a temperature
equal to or greater than the selected softening temperature
and less than the melting temperature to cause the binder
fibers to soften and adhere to the insulative fibers to
connect certain of the insulative fibers to one another;
and, cooling the batt to harden the softened binder fibers.
20Turning now to the drawings, which depict the presently
preferred embodiments of the invention for the purpose of
illustrating the practice thereof and not by way of
limitation of the scope of the invention, a method for
producing an insulative batt is illustrated in Fig. 1 in
which bales of cotton 1 or another insulative or "bulk"
fiber are first loosened up and separated into individual
fibers or small groups of fibers by the hopper bale-breaker
2. Other hopper bale-breakers 2 are utilized to "open"
binder fibers, stilt fibers, or other types of fibers to be
blended with or added to fibers produced by bale-breaker 2.
Fibers from hopper bale-breaker 2 are directed into blender-
opener 4. Binder fibers, stilt fibers or other types of
insulative fibers can be added to blender-opener 4 in any
desired proportion with insulative fibers 3 from hopper-
breaker 2. Fibers from blender-opener 4 are transported 5 to
the picker or scratcher 6. Picker 6 forms the loose fibers
into a sheet (the lap) which is wound into a roll 7. Roll 7
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is transported 8 to a revolving flat card machine 9 and fed
into machine 9. Card machine 9 includes a taker-in roller or
licker-in 10 provided with teeth which tear away small
bunches of fiber from the lap. Main cylinder 11 is provided
with teeth which strip small bunches of fiber from the
licker-in. Narrow bars or flats 12 are carried by an endless
belt 13 and are provided with teeth which exercise a combing
action and remove impurities. The web from main cylinder 11
travels around doffer 14 and is directed or transported 15
to a lapper 16. The lapper folds the web 15 upon itself to
produce a batt of desired thickness. Lapper 16 is preferably
a cross-lapper, but can be any conventional lapper machine.
Similarly, card machine 9, picker 6, blender-opener 4 and
bale-breaker 2 can be replaced with any conventional
apparatus performing similar functions with respect to the
insulative, stilt, and binder fibers used on the practice of
the method of the invention. Batt produced by the lapper 16
is transported 17 to a bonding oven 18 which heats the batt
to a temperature sufficient to soften binder fibers
contained in the batt. When the binder fibers soften, they
adhere to insulative fibers and bind the insulative fibers
to one another. The binder fibers can be intermixed with
insulative fibers in blender-opener 4 or added to the web
during its transport 15 to lapper 16, during lapping 16, or
during transport 17 of the lapped web to oven 18. Heat
treated batt from oven 18 is cooled and transported 19 to
additional processing stations 20. Stations 20 can add fire
retardant to the batt in the form of a spray or powder.
Common fire retardation compositions include borates,
aluminum hydrate, halogenated hydrocarbons, and decabromo
diphensyl dether. Chemical-preservatives can be added to the
batt to resist mildew and attack by insects. If desired,
such fire retardants and chemical preservatives can be added
to the web at any convenient processing point before or
after the web is produced by card machine 9.
Another procedure performed by processing stations 20
is cutting the batt. The batt can be cut into short
segments, balls, and any other desired shape and dimension.
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The insulative fiber(s) added to blender-opener 4 in
Fig. 1 can be selected from natural fibers like cotton,
wool, flax, jute, mohair, silk, ramie, hemp and asbestos or
from synthetic fibers like rayon, acetate, nylon, polyester,
polyenes, acrylics, vinyons, kevlar or other monoacrylic,
acrylic, or polyamide fibers. The proportion of an
insulative fiber added to the blender-opener 4 can vary as
desired and typically is in the range of 0 to 95% by weight.
As earlier noted, a binder fiber is added to the insulative
fibers. Binder fibers are added to blender-opener 4 in the
proportion in the range of two to eighty percent by weight
of the insulative or bulk fiber. The binder fiber has a
softening temperature which is less than the melting
temperature of any of the insulative fibers added to
blender-opener 4. Accordingly, when a batt from lapper 16
passes through oven 18, oven 18 is heated to a temperature
equal to or greater than the softening temperature of the
binder fiber and less than the melting temperature of any of
the insulative or bulk fibers. Oven 18 thus causes the
binder fibers to soften and adhere to the insulative fibers
and bond or interconnect insulative fibers to one another.
As used herein, the term "soften" when applied to binder
fibers means that the binder fiber begins to lose its
hardness and/or melts such that the binder fiber can adhere
to and interconnect insulative fibers after the binder
fibers are heated to a selected temperature and then cooled
to a normal room temperature of 78F. Some binder fibers
become "sticky" and adhere to an insulative fiber before the
binder fiber melts. Other binder fibers have to melt before
they will adhere to insulative fibers. A melted binder fiber
and a softened "sticky" binder fiber each comprise a
"softened" binder fiber. The presently preferred binder
fiber is a polyester fiber. Any other desired synthetic or
natural fiber can be utilized as a binder fiber.
The use of polyester fibers is known in connection with
the production of medical blankets and feminine hygiene
pads. In such uses, polyester fibers form a water resistent
layer. For example, on medical blankets of the type utilized
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2~48938
in operating rooms, polyester fibers form the backing on the
blanket. On KOTEX feminine hygiene napkins, a water
resistant sleeve made from polyester surrounds the inner
absorbent part of the napkin. These uses bear no relation to
the production of thermal insulation and do not suggest the
function of polyester binder fibers in the method of the
invention.
The binder fibers can be added to lap 7 or can be added
to the web at any point after the web is produced by card
machine 9 and prior to heating of the batt in oven 18. The
melting temperature of the binder fibers can vary as desired
as long as the melting temperature is greater than the
temperature(s) at which the binder fibers are processed by
machines 4, 6, 9, and 16 in the method of the invention up
until the batt is heated in oven 18, provided that the
melting temperature of the insulative fibers is greater than
the softening temperature of the binder fibers, and provided
that the softening temperature is at least 130F. Binder
fibers with softening temperatures less than 130F are
inconvenient because the binder material may soften or melt
when maintained in an non-air conditioned storage shed in
the summer or in the enclosed non-air conditioned bed of a
vehicle. The preferred melting temperature of the binder
fibers is presently in the range of 180F to 450F. The
binder fibers can take the form of actual fiber or of powder
produced from fibers or from the material used to make
fibers. Adding binder fibers in powder form, particularly in
blender-opener 4, can be advantageous. In contrast, the
insulative fibers comprising a large portion of the batt are
in true fiber form. Otherwise, the insulative fibers could
not be processed by bale-breaker 2, blender-opener 4, picker
6, and card machine 9. The binder fibers have a length in
the range of 0.5 to 2.0 inches, with a length of 1.5 inches
being preferred. Eastman Kodak 410 binder fiber is presently
a preferred binder fiber in the practice of the invention.
The insulative fiber(s) 1 used in the practice of the
invention are 0.5 inches or longer, and are typically in the
range of 0.5 inch to 1.5 inches long. The insulative fiber
2048938
can have a denier in excess of 3.0, but a denier of 3.0 or
less is preferred because the insulative batt produced is
unusually light. When cotton is utilized, a denier in the
range of 2.4 to 3.0 is preferred. The web produced by the
car machine 9 has a preferred thickness in the range of 1/16
inch to 3/16 inch, even though a card machine can produce
much thinner or thicker webs. By way of example, when a
Hollingsworth 2.5-Meter-working-width MASTERCARD card
machine is utilized, the licker-in roll 10 uses wire in the
range of 40 to 50 teeth per square inch, preferably 50 teeth
per square inch, and a working angle of 15 to 25,
preferably 20; the main cylinder 11 uses wire in the range
of 300 to 700 teeth per square inch, preferably 500 teeth
per square inch, and a working range in the range of 17 to
27, preferably 22; and, the doffer 14 uses wire in the
range of 150 to 250 teeth per square inch, preferably 250
teeth per square inch, and a working angle in the range of
17 to 27, preferably 22. If desired, a plurality of card
machines 9 can be utilized to produce web fed to lapper 16.
An air lay machine, garnet or comparable web weaving machine
can be utilized in place of card machine 9. The air lay
machine produces a heavier non-uniform web. A garnet machine
would produce web having larger air pockets than the web
produced by card machine 9. The card machine is preferred in
the practice of the invention because it discretely
separates fibers and produces a relatively uniform fine
kleenex-like spider web principally comprised of parallel,
elongate strands of thread. These parallel strands comprise
approximately 80 to 85~ by weight, or more, o~ the web,
while the remaining weight of the web consists of strands
which are at an angle to and interconnect the parallel,
elongate strands. Accordingly, when web produced by a card
machine 9 is cross lapped 16, each succeeding layer of web
in the batt has a longitudinal axis which is parallel to the
parallel, elongate strands comprising the majority of the
web layer and which is rotated 20 to 60, preferably 30,
from the longitudinal axis of the preceding web layer in the
batt.
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g
When web produced by card machine 9 is being lapped by
lapper 16, stilt fibers can be spread on a lapped layer of
web just prior to the time that lapper 16 covers the first
lapped layer of web with another web layer. These stilt
fibers are 1/16 inch to 3/8 inch long, preferably 1/8 inch
to 1/4 inch long. The stilt fibers function to spread apart
and maintain a space between adjacent lapped web layers
comprising the batt. When the batt is heated in oven 18,
softened binder fibers adhere to and interconnect stilt
fibers and insulative fibers. When the stilt fibers are
applied to the web, additional binder fibers can be applied
with the stilt fibers to facilitate the bonding of stilt
fibers to insulative fibers. Stilt fibers are preferably
applied to horizontally disposed layers of web during
lapping of the web by lapper 16 because the stilt fibers
tend to "ride" on top of lower layer of web to separate the
lower layer from the web layer adjacent and just above the
lower layer. When the batt is heated by oven 18, the stilt
layers are bonded to insulative fibers and the stilt fibers
intermediate two adjacent web layers maintain a spacing in
the range of 1/32 inch to 1/8 inch, typically 1/16 inch. The
spacing between web layers produced by the stilt fibers
significantly increases the insulative value and decreases
the weight of insulation produced in accordance with the
invention. Stilt fibers can, if desired, be blended with
longer insulative fibers in blender-opener 4 or can be
spread on or applied to the web at any point in the process
of the invention after the web is produced by and leaves the
card machine 9. KODAFIL 435 is a synthetic fiber which can
be utilized as a stilt fiber, as are cotton fibers having a
length in the range of 1/8 inch to 3/8 inch. Stilt fibers,
like insulative fibers, have a melting point or temperature
which is greater than the softening temperature of binder
fibers used in the insulation batt of the invention.
Another embodiment of the invention is illustrated in
Fig. 2 in which bales of cotton 1 or another insulative or
"bulk" fibers are loosed up and separated into individual
fibers or small groups of fibers by the hopper bale-breaker
20489~8
2. Other hopper bale-breakers 2 can be utilized to "open"
binder fibers, stilt fibers, or other types of fibers to be
blended with or added to fibers produced by bale-breaker 2.
Fibers from hopper bale-breaker 2 are directed 3 into the
blender-opener 4. Binder fibers, stilt fibers, or other
types of insulative fibers can be added to blender-opener 4
in any desired proportion with insulative fibers 3 from
hopper-breaker 2. Fibers from the blender-opener 4 are
transported 5 to the dispensing funnel 23 of the opener 21.
Fibers 36 falling into mixing chamber 33 of opener 21
through funnel 23 are intermixed, torn and separated by
turbulence 37 caused by at least one incoming stream of air
22. Air stream 22 can also open fibers by causing the fibers
to impact a beater or grate of the type shown in opener 4 or
to impact some other structural member. The air introduced
into chamber 33 by stream 22 passes into chamber 34 in the
manner indicated by arrow 24. The air stream 24 tLaveling
into chamber 34 is bifurcated into a stream 26 passing out
through vent 25 and a stream 28 passing out through vent 38.
Pivoting door 37 covers vent 38. Intermixed fibers 36
carried into chamber 34 by air stream 24 settle or are
carried into rectangular steel plate 31. Vibrator means 32
vibrate plate 31 to settle and compact the fibers 36 which
gather on plate 31. When a sufficient weight of fibers has
gathered on plate 31, conveyor 30 causes the batt 29 formed
by the compacted fibers to travel outwardly in the direction
of arrow 40 through vent 38. The pressure of air stream 28
against fibers 36 on plate 31 also facilitates the
compacting of the fibers which gather on plate 31. The
compacting pressure of air stream 28 may obviate the need
for using vibrator means 32. Other compacting means can be
used separately from or in combination with air stream 28
and means 32 to compact and amalgamate fibers. Plate 31
rests on scales or weight means which determines the weight
of fibers 36 collected on plate 31. When the weight means
determines that the weight has reached a selected value,
conveyor 30 is operated to transport the batt 29 formed on
plate 31 out from chamber 34 in the direction of arrow A. If
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desired, conveyor 30 can gradually continually transport a
single elongate batt 29 from opener 21 as the batt is
produced by opener 21. The batt 29 is moved by conveyor 30
into oven 18 for heat treatment. Heat treated batt from oven
18 is cooled and transported to additional processing
stations 20. Stations 20 can add fire retardant to the batt
in the form of a spray or powder, or chemical preservatives
can be added to the batt to resist mildew and attack by
insects. Another procedure performed by processing stations
20 is cutting the batt. The batt can be cut into short
segments, balls, and any other desired shape and dimension.
Conventional methods of producing an insulative batt
utilize a carding machine 9. The process of Fig. 2
eliminates the necessity of utilizing a carding machine and
increases the production rate by about five times over
conventional insulative batt production methods which
incorporate a carding machine. A principal feature of the
method of Fig. 2 is the utilization of one or more "openers"
to form an insulative batt which is fed directly into oven
18. As used herein, an opener is a machine which utilizes
air turbulence and possibly beaters, grates or other means
to intermix and separate fibers and which can al~o include
means for collecting and at least partially compacting the
intermixed randomly oriented fibers to form a loose batt.
Opener 21 and opener 4 are examples of openers.
The same types, quantities, and proportions of
insulative fibers, binder fibers, and stilt fibers utilized
in the method of Fig. l can be utilized in the method of
Fig. 2. The weight percent of stilt fibers in a batt
produced in accordance with the method of Fig. 2 is
preferably in the range of 5% to 20%.
A three and a half inches thick insulative batt
produced in accordance with the method of Fig. 2 presently
has a weight of about two to two and a half ounces per
square foot and an R value of ll. The thickness of batt 29
ordinarily is in the range of about one to eight inches.
Opener 21 can comprise the VIBRACHUTE CARD FEEDER
produced by John D. Hollingsworth On Wheels, Inc. of
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12
Greenville, SC 29602-0516, USA.
The following examples are presented, not by way of
limitation of the scope of the invention, but to illustrate
to those skilled in the art the practice of various of the
presently preferred embodiments of the invention and to
distinguish the invention from the prior art.
EXAMPLE 1
Cotton Fibers having a length of 7/8 inch are selected
as insulative fibers. Cotton gin moates and linters each
having a length in the range of 1/8 inch to 1/4 inch are
selected as stilt fibers. E. I. du Pont Dacron D-262
polyester fibers are selected as binder fibers. The
insulative fibers and stilt fibers have a denier of 2.8. The
polyester fibers have a denier of 1.8, an elongate percent
of 200, a length of 1.5 inches, a melting point of 142C
lS (softening at 78C) and a bonding temperature of 155C
(surface) with respect to cotton, i.e., the Dacron D-262
polyester bonds to cotton fibers when heated to 155C. The
melting point of the insulative fibers exceeds 160C.
A batt is formed using the method of Fig. 1. The
insulative fibers, stilt fibers, and binder fibers are
blended together in a blender-opener 4 and processed with a
picker 6 and card machine 9 to form a web which is
transported 15 to a lapper 16. The insulative fibers
comprise 60% by weight of the blended mixture; the cotton
moates 20% by weight of the blended mixture; and, the binder
particles 20% by weight of the blended mixture. The batt
produced by lapper 16 is transported 17 to oven 18. The bat
is heated in oven 18 to a temperature equal to or in excess
of 155C to soften the polyester binder fibers and bond them
to the insulative and stilt fibers. After being removed from
oven 18 and cooled, the batt is cut 20 into six foot long
sections and packaged. The batt is 2.9 inches thick and one
foot wide and has a density of 8 ounces per cubic foot. The
thickness, length, and width of the batt can be varied as
desired. The insulation value or "R value" of the batt is R-
11. The "R-value" of insulation indicates the time in hours
required for one BTU to be transmitted through a one square
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foot area of the insulation when there i5 a difference of
one degree Fahrenheit between the two opposing outer
surfaces of the insulation.
The 2.9 inch thick R-ll batt produced in this Example
is lighter than a comparably sized fiberglass batt and has
a greater R value than the fiberglass batt.
EXAMPLE 2
Cotton fibers having a length of one inch, wool fibers
having a length of 7/8 inch, and rayon fibers having a
length of 1.5 inches are selected as insulative fibers.
Cotton gin moates and linters and acrylic fibers each having
a length in the range of 1~8 inch to 1/4 inch are selected
as stilt fibers. E. I. du Pont D-262 polyester fibers are
selected as binder fibers. The insulative fibers and stilt
fibers have a denier of 2.6. The polyester fibers have a
denier of 2.2, an elongate percent of 200, a length of one
inch, a melting point of 142C (softening at 78C) and a
bonding temperature of 155C (surface) with respect to
cotton and 120C with respect to acrylic fibers. The melting
point of the insulative fibers exceeds 160C.
A batt is formed using the method of Fig. 1. The
insulative fibers and binder fibers are blended together in
a blender-opener 4 and processed with a picker 6 and card
machine 9 to form a web which is transported 15 to lapper
16. The stilt fibers are separately blended together in a
blender-opener 4 with binder fibers to form a stilt-binder
fiber mixture. The insulative fibers comprise 70% by weight
of the web produced by the card machine 9, while the binder
fibers comprise 30% by weight of the web produced by card
machine 9. The stilt fibers comprise 60% by weight of the
stilt-binder fiber mixture, while the binder fibers comprise
40% by weight of the stilt-binder fiber mixture. While the
web produced by card machine 9 is being lapped, a 1/8 inch
to 1/4 inch layer of the stilt-binder fiber mixture is
spread on the upper horizontal surface of each layer of the
web deposited by the lapper 16. The layer of the stilt-
binder fiber mixture is deposited before the lapper 16 lays
down on the upper horizontal surface of a deposited or
20489~8
14
"laid" web layer the next subsequent layer. Accordingly,
after lapper 16 has produced a batt, each adjacent pair of
horizontally oriented web layers comprising the batt will
sandwich a stilt-binder fiber layer which is 1/8 inch to 1/4
inch thick.
The batt produced by lapper 16 is heated in oven 18 to
a temperature of 120C so the binder fibers soften and bond
to both the cotton and acrylic insulative fibers. After the
binder fibers have bonded to the insulative fibers, the batt
is removed from the oven and cooled. At processing stations
20 the batt is cut into lengths 50 feet long and rolled and
packaged. The batt is 2.9 inches thick, 1 foot wide and has
an R value of about 12. The thickness, width and length of
the batt can be varied as desired. The stilt fibers maintain
a spacing o about 1/8 inch between adjacent web layers in
the batt. The stilt-binder fiber mixture added to the batt
comprises about 15% by weight of the finished batt, with the
insulative-binder fiber mixture of the web comprising the
remaining 85~ by weight of the batt. The density of the batt
is 7 ounces per cubic foot.
The stilt fibers can comprise 1% to 50~ by weight of
the insulation batt produced by the method of the invention.
Preferably, the stilt particles comprise 5% to 20% by weight
of the batt.
When the cotton batt of Example 2 is five inches thick,
the R value of the batt is about 19. A fiberglass batt must
be six inches thick to achieve an R value of 19. When the
cotton batt of Example 2 is 7.9 inches thick, it has an R
value of 30. When the cotton batt of Example 2 is 2.9 inches
thick, the R value of the batt is, as noted, about 11. A
fiberglass batt with a thickness of 3.5 inches weighs .23
lbs per square foot of insulation. The 2.9 inch thick cotton
insulation of Example 2 weighs about 0.12 lbs per square
foot of insulation.
EXAMPLE 3
Cotton fibers having a length of 7/8 inch are selected
as insulative fibers. Cotton gin moates and linters each
having a length in the range of 1/8 inch to 1/4 inch are
20~8938
selected as stilt fibers. E. I. du Pont Dacron D-262
polyester fibers are selected as binder fibers. The
insulative fibers and stilt fibers have a denier of 2.8. The
polyester fibers have a denier of 1.8, an elongate percent
of 200, a length of 1.5 inches, a melting point of 142C
(softening at 78C) and a bonding temperature of 155C
(surface) with respect to cotton, i.e., Dacron D-262
polyester bonds to cotton fibers when heated to 155C. The
melting point of the insulative fibers exceeds 160C.
A batt is formed utilizing apparatus illustrated in
Fig. 2. If desired, and appropriate, a hopper bale-breaker
2 can be utilized to open the insulative, stilt or binder
fibers. The insulative fibers, stilt fibers, and binder
fibers are blended together in a blender-opener 4 and
processed with a picker 6 and a card machine 9 to form a web
which is transported 15 to a lapper 16. The insulative
fibers comprise 55~ by weight of the blended mixture; the
cotton moates 15% by weight of the blended mixture; and, the
binder fibers 30~ by weight of the blended fiber mixture.
Blended fibers from opener 4 are transported 5 to dispensing
funnel 23 of opener 21. Fibers 36 falling through funnel 23
into chamber 33 are intermixed by air stream 22 in the
manner earlier described. The air introduced into chamber 33
by stream 22 passes into chamber 34 in the manner indicated
by arrow 24. The air stream 24 traveling into chamber 34 is
bifurcated into a stream 26 passing out through vent 25 and
a stream 28 passing out through vent 28. Intermixed blended
fibers 36 carried into chamber 34 by air stream 24 settle or
are carried onto rectangular steel plate 31. Vibrator means
32 vibrate plate 31 to settle and compact the fibers 36
which gather on plate 31. When a sufficient weight of fibers
has gathered on plate 31, conveyor 30 causes the batt 29
formed by the compacted fibers to travel outwardly in the
; direction of arrow 40 through vent 38. Conveyor 30
transports 35 batt 29 to oven 18. Oven 18 heats batt 29 to
a temperature equal to or in excess of 155C to soften the
polyester fibers and bond them to the insulative and stilt
fibers. The temperature in oven 18, while in excess of
, ~ .
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16
nl55F, is not sufficient to melt the insulative or stilt
fibers. After being removed from the oven 18, the batt 29 is
cooled to room temperature. Batt 29 is cut 20 or subjected
to other selected processing steps.
In the embodiment of the invention illustrated in Figs.
3 and 4, blended fibers from opener 4 are blown under
pressure 5 through conduit 41 into hold box 42. The air
pressure utilized is unusually high and is in the range of
3000 to 7000 cubic feet per minute. This high air pressure
is important because it tends to compact fibers into fixed
hold box or ccntainer 42. Air escapes from box 42 through
screen 50 in the direction indicated by arrows A in Figs. 3,
4. Wire roller 43 pu115 loosely compacted fibers 57 from box
42. Outwardly extending rods 54 on roller 44 pull fibers 57
from wire roller 43 and direct the fibers 57 into fixed
chute feed box or container 45. Gravity and rollers 43, 44,
47, 48 move the fibers downwardly through box 45. As fibers
57 move through box 45, spanker plate 46 reciprocates in the
directions indicated by arrow C and contacts and packs and
compresses fibers 57 against the front wall 56 of feed box
45 to form batt 51. Fluted roller 47 pulls batt 51 from box
45. Fluted roller 48 pulls batt 51 from roller 47 and
compresses batt 51 between roller 48 and fixed arcuate
support plate 55. Compressed batt 51 travels onto conveyor
belt 30 in the direction of arrow 35 to an oven 18 ~not
shown in Figs. 3 and 4). Conveyor belt 30 transports the
batt 51 at a speed of from 20 feet per minute up to 60 feet
per minute. In contrast, a conveyor which removes material
from a carding machine only travels at about 10 to 15 feet
per minute. In Fig. 3, the outwardly extending wires of
roller 43, the rods 54 of roller 44, and the outwardly
extending flutes on rollers 47 and 48 are omitted for the
sake of clarity. Each flute on rollers 47 and 48 comprises
an elongate panel which is generally perpendicular to the
tangent line at the point the panel is connected to the
outer cylindrical surface of the rGller and which converges
or tapers as the distance from the cylindrical surface of
the roller increases. The taper of each flute is evident in
.
20489~8
1~
Fig. 4. The speed of oscillation of plate 46 is 40 to 80
reciprocations per minute. Rollers 43, 44, 47, 48 move batt
51 at a speed in the range of 20 feet per minute to about 60
feet per minute.
The quantity of fiber fed through conduit 21 into box
42 is sufficient to produce a batt 51 having the desired
weight per cubic foot. For example, if the width D of box ~5
is ninety inches and the width of the batt 51 produced in
and dispensed by box 45 is therefore ninety inches, then
about 1124 pounds of fiber per hour is fed through conduit
21 into box 4~ to produce a ninety inch wide--four inch
thick batt at a rate of twenty feet per minute such that the
batt has a weight of about six ounces per cubic foot. The
batt 51 produced by the apparatus of Figs. 4 and 5 must
weigh at least six ounces per cubic foot of batt, preferably
from six to fifteen ounces per cubic foot. When batts of
lesser weight per cubic feet are attempted, the fibers tend
to fall through box 45 and not be compacted by spanker plate
46. If the batt 51 has a thickness, indicated by arrows T in
Fig. 4, that equals four inches, then the batt weighs at
least about two ounces per square foot area of four inch
batt, i.e., the batt weighs at least six ounces per cubic
foot of batt 51.
The thickness T of batt 51 dispensed by box 45
presently can be in the range of from about one-quarter of
an inch up to about the width of the box. The width of the
box 45 is indicated by arrows F in Fig. 3 and presently is
about eight inches. The height of box 45, indicated by
arrows E, is presently about eighteen inches.
The great virtue of the apparatus and method of Figs.
4 and 5 is that it can, for example, produce a four inch
thick batt weighing about six ounces per cubic foot at a
rate of twenty feet per minute or more. In order to produce
a similar batt with a carding machine, the output from the
carding machine typically is taken at the rate of ten feet
per minute and cross lapped four times to produce a batt
which has eight layers, has a thickness of four inches, and
has a weight of about 3.6 to 4.5 ounces per cubic foot.
;
- 2~k89~8
18
~ s the speed at which batt 51 moves through and is
dispensed from box 45 increases, there is a greater
likelihood that portions of batt 51 will have "weak" areas
which have less density or weight than other portions of
batt. This is particularly the case at high rates of
production in excess of fifty feet per minute. When batt 51
moves through the machine of Figs. 4 and 5 at such high
rates of speed, two or more machines of the type shown in
Figs. 4 and 5 can be used simultaneously and the batt output
from one machine stacked directly on top of and in register
with the batt output from the other machine(s) to form a
batt having two or more parallel layers. One batt is not
folded on top of the other batt but instead is simply laid
on the other batt in a long strip and without being folded.
Each layer has approximately the same elongate shape and
dimension as the other adjoining layer(s). When the multi-
layered batt is heated in oven 18, the binder fibers
interconnect the stacked layers. One layer tends to cover
and compensate for any areas in tne other layer which have
a lower-than-desired weight or density compared to other
areas in said other layer. Each layer tends not to have
"weak" or low weight areas at the same locations as in the
adjoining layer. And, if for some reason two adjoining
layers have low weight areas at the same locations along the
lengths of the layer, one layer is placed on top of the
other layer such that areas of low weight in one layer are
offset from low weight or low density areas in the other
adjoining layer. The stacking of the batts produced by
multiple machines of the type shown in Figs. 4 and 5
compensates for structural weakness in individual batts and
facilitates the rapid production of thick or hiyh density
batts. High density batts can be produced by forming a thick
batt and compressing the thick batt with rollers.
Having described my invention in such terms as to
enable those skilled in the art to understand and practice
it, and having identified the presently preferred
embodiments thereof, I Claim:
