Note: Descriptions are shown in the official language in which they were submitted.
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~2317
DFSC~PTI~
INSULATION BATT WITH LOW FRICTION FACING
~CH2~I~AL FI~
This invention pertains to mineral fiber
insulation products. More particularly, this invention
relates to mineral fiber insulation batts having a facing
adhered thereto.
B~CK~O~ID An~
In the manufacture of insulation batts from
mineral fibers, it is a commonly-used practice to fiberize
the mineral fibers from molten mineral material to
distribute them on a collecting conveyor to form a pack.
Typically the fibers are sprayed with an organic binder,
s and the pack is passed through a curing oven. The pack is
then cut into individual pieces or batts. In some cases a
facing material is added to the pack prior to the cutting
step.
One of the uses for insulation batts is to
reinsulate the attic spaces of residential dwellings.
Typically, reinsulation batts are unfaced in order to
avoid introducing a new vapor barrier within the
insulation layers within the attic. Manufacturers'
recommendations for reinsulation of attic spaces is to
either use an unfaced batt, or to physically perforate the
facing on a faced product by providing knife slits or
other perforations in the material.
One of the problems with installing additional
insulation batts in an attic space is that it is difficult
for the insulation batts to be slid into place. The
unfaced reinsulation batt has a high coefficient of
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kinetic friction when pushed along the existing surface
i.e., the unfaced existing attic insulation. This is
particularly true at the edges of the attic space where
the roof slope meets the attic floor. The amount of
friction between two mineral batts is considerable, and it
is not easy to slide the reinsulation batt along the
surface of existing batts in the attic space.
Another problem associated with reinsulating
residential attic spaces is that the existing and new
insulation materials generate significant quantities of
dust, which are irritating to the installers. Typically,
reinsulation is accomplished as a do-it-yourself project
by residential homeowners. It would be beneficial if
batts for reinsulating attic spaces were made to be easily
slid in place over existing insulation in the attic.
Further, it would be beneficial to provide some means for
containing dust associated with the batts used for
reinsulation.
Encapsulated insulation packages are known in the
- 20 art. Mclaughlin, in U.S. Patent 2,113,068 and Parker, in
U.S. Patent 2,913,104, each disclose insulation packages
in which mineral wool is covered by a wrapper.
Facings of different materials have been proposed
for insulation batts. These include kraft paper, and
polyethylene films, as disclosed in U.S. Patent 4,696,138
to Bullock. Bullock teaches a vapor-permeable
polyethylene facing on four sides of a batt. The purpose
of Bullock's facing is to stop convection from occurring
in glass fiber insulation products.
fy~o in Y S ~-~t q,9~7,705 A~Folo~ n
i..3ulation produat c~vorc~ ~ith ~ v por ~arricr of 1.02
2.03~ 5 r~t~r~ (t to 2 ~;1) polyqt~yl~n~ ~hi6 p~o~-~t
ic co~rl~t~ly on~-p~ t~d, ~nA th~o i~ ~o ~o~city for
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French Patent No. 2,418,082 teaches a mineral
wool sheet onto which a polyvinylidene chloride foil
has been fused. The mineral wool sheet ls used to
provide thermal or acoustic insulation. German
Gebrauchsmuster No. 8505179 describes a mineral fiber
insulation batt covered with a metallized polymeric
facing adhered to the batt.
Syme in U.S. Patent 4,927,705 describes an
insulation product covered with a vapor barrier of
25.4x10-6 to 50.8x10-6 meters (1 to 2 mil) polyethylene.
This product is a completely encapsulated, and there
is no porosity for
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passing moisture or for enabling compression during
packaging. The ability to compress the insulation batt
for packaging and have the insulation batt recover to a
reasonable thickness once the package is opened for
installation in the attic is a product requirement.
A very important aspect of any insulation product
for retrofit situations is that the product must be
nonflammable, i.e., it must pass the ASTM E84 flame spread
test with a flame spread rating of 25 or less. One of the
problems associated with some of the encapsulated mineral
fi~er insulation batts of the prior art is that the
adhesive used to adhere the facing to the batt would
itself contribute to a flammability problem. The adhesive
prevents the product from passing the flame spread test
with a flame spread rating of 25 or less. Such products
invariably require expensive fire retardants to pass the
test. Another problem with encapsulated insulation batts
proposed to date is that the encapsulation materials
prohibitively increase the cost of the insulation batt.
In view of the above, it would be desirable to
provide an encapsulated mineral fiber insulation batt that
has a thin facing, low coefficient of sliding friction
over existing insulation in the attic, means to adhere the
facing to the batt for handleability without using
expensive fire retardants and without failing the ASTM
flame spread test. Also, the insulation product should be
at least in part highly porous to enable the rapid
compression of the batt for packaging, and the batt must
be capable of nearly full recovery upon the opening of the
package. It is to be understood that although the product
of the invention is designed for retrofit insulation in a
residential attic, the product can also be used in other
insulation applications such as insulating wall cavities,
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basement ceilings, residential new construction, and
insulation for commercial buildings.
In accordance with the invention there is now
provided a compressible mineral fiber insulation batt
having opposed major surfaces and opposed side
surfaces and a polymeric facing applied to both of the
major surfaces, the facing being less than or equal to
25.4x10-6 meters (1 mil) in thickness and being adhered
to the batt to prevent relative movement between the
facing and the batt, characterised in that the facing
- is vapor permeable and is of sufficiently low mass to
exhibit a flame spread rating of 25 or less in the
adhered condition, that the opposed side surfaces of
the batt are covered with a highly porous membrane to
enable quick air escape from the batt under conditions
of rapid compression, and that the batt is capable of
recovering to a predetermined thickness after release
from compression to one-fourth of the predetermined
thickness.
It has been found that by using a very thin
facing material, the product can pass the ASTM flame
spread test, even when the facing is adhered to the
mineral fiber batt with an adhesive.
The facing material preferably has a thlckness of
less than or equal to 15.2x10-6 meters (0.5 mil) and
more preferably less than or equal to 10.1x10-6 meters
(0.4 mil).
One of the valuable features of the fiber
insulation batt of the invention is that the
coefficient of kinetic friction of the faced batt is
less than 1.0 when the faced batt is dragged across a
surface of an unfaced glass fiber batt having a
density of about 8.01-
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12.81 Kg/M3 (0.5 to about 0.8 pounds per cubic foot).
This low coefficient of kinetic friction enables the do-
it-yourself attic installation installer to push or slide
the batt of the invention across the top of existing
insulation in the attic, thereby facilitating easy
installation of the retrofit batts into the farthest
reaches of an attic.
The polymeric facing is adhered to both major
surfaces of the batt with a fastening means. Preferably
the fastening means is a small amount of adhesive
material. The adhesive material is of a sufficiently
small amount as to enable the insulation batt not to
exceed a flame spread rating of 25 by the ASTM E84 flame
spread test, while ~eing sufficient to ~ond the facing to
the mineral fiber batt and enable the batt to be picked up
and handled by the facing.
- In another particular embodiment of the
polymeric facing is adhered to one or both of the opposed
side surfaces of the batt.
- 20
~ n~ ~o ~o t~ a~n~ q d~ l~5
Figure I lS a perspect1ve vlew of a mineral fiber
insulation batt having-
facing material on both the major surfaces and on the sidesurfaceJ c~nd 2
Figure is a schematic view of apparatus used in
a test to evaluate the coefficient of kinetic friction of
faced insulation batts.
This invention will be described in terms of a
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glass fiber insulation batt. It is to be understood that
the mineral fiber insulation batt can be comprised of
other types of mineral fibers, including fibers made from
rock, slag and basalt.
Referring to Fisure l, insulation batt lO is
generally rectangular and has major surfaces 12, side
- surfaces 14, and end surfaces 16. Attached to the major
surfaces is an encapsulation material or polymeric facinq
material 18. This material can be anything suitable to
contain the dust and provide a low kinetic friction
surface. Preferably the material is a polymeric material,
and most preferably it is a polyethylene. A specific
polyethylene material found to be useful is a high
density, high molecular weight polyethylene.
In other embodiments of the invention the facing
is comprised of polypropylene. A preferred polypropylene
facing is a biaxially oriented polypropyle~e.
The facing on the major surfaces - vapor
permeable. A vapor impermeable
membrane can be rendered vapor permeable by means of
perforating the facing material.
Th~ facing material is less than or equal to
2 5~ C~~
l.0~ 5 meters (~l 0 m ll ~ thickness, preferably less
than or equal to 6;l~y 6 meters (O.6 mil) ~n~th1ic~ess,
and most preferably less than or equal to s;O~F 6 meters
(0.4 mil) in thickness. The facing material must be
sufficiently thin to avoid high material costs and to
minimize fuel contributed during fire testing.
The facing material is attached to the major
surfaces of the batt by any suitable fastening means, such
as adhesive 20. The fastening means could also be, for
example, velcro attachment means, sticking or a heat
sealing process. A suitable adhesive is a pressure
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sensitive hot melt, such as HL-2707 ~rom H.B. Fuller
Company, applied at a rate of 2.13~ G.../l~ (0.2 grams per
square foot).
The fastening means must provide a bond between
the facing and the mineral fiber batt sufficient to enable
the batt to be handled by the facing material. Therefore,
the fastening means acts to prevent relative movement
between the facing and the batt.
The fastening means, particularly if it is an
adhesive, must be of sufficiently low mass so as to not
unduly increase the flame spread of the batt with the
facing in the adhered condition. The flame spread test is
the ASTM E84 test. The measurement under the ASTM E84
flame spread test must be taken with the facing material
in the adhered condition. Further, the mass of the facing
material and the adhesive material is sufficiently low to
pass the flame spread test with a flame spread rating of
25 or less in the absence of fire retardants. For
purposes of this invention, the term "absence of fire 20 retardants" means that the material either actually
contains no fire retardants, or contains fire retardants
in such an insubstantial amount that the facing, in the
adhered condition, would still pass the flame spread test
with a flame spread rating of 25 or less if the fire
retardant were left out of the product. This provides a
considerable enhancement over the art in terms of material
costs since a fire retardant is not needed. The test
consists of determining the extent to which flames travel
along the product under specified conditions when the
product is exposed to a flame at one end.
As shown in Figure 1, the side surfaces are
u,.c~,ed. Thic ~r-~ r-pi~ cc~,~ro~ion of tho b~tt
du.i..y a p-~ak-~in~ qp~r~t;~n 5i~c~ m~st ;n~l t;on ~t
. I
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~E~ ~h~y ~o~osso~ A~n~ p~k~in~ a~d~r~ncport~
p4r-~-nt f~r th~ w;~;n th~_in~ ti~n F~ckage-
~~rcl~s~ pi~y ~ri~ th~ ~m~c~i~n ~ Q~,
~ ho~m in Fig~ a, ~h~ inc~ t;~n h-tt 6a~b~
provided with side facing material 22. The side facing
material can be any material to contain the dust within
the insulation product, while still being sufficiently
porous to enable the rapid evacuation of air from within
the batt during compression. The most expedient facing
material may be the same facing material used on the major
surfaces, but being highly perforated. Alternatively, the
facing material can be cut to produce flaps to enable air
escape during compression, but present a rather solid-
looking appearance under static conditions. Additional
side facing materials useful for this invention would be
any scrim or other open-weave material, woven or nonwoven,
made from polymeric fibers or glass fibers. Preferably,
the side facing material has openings in at least 10
percent of its surface during the compression process. In
one embodiment of the invention, the side facing material
- 22, as well as the facing material 18, is adhered to the
batt.
The addition of the facing material to what would
normally be an unfaced batt, imparts a structure to the
batt which enhances its handleability and installability
in residential attics. Further, since the facing material
covers the batt, any surface irregularities which would
constitute a visual surface defect are covered up.
Consequently, a certain amount of scrap or recycled glass
fiber material may be added to the product without
detracting from its visual appearance. Further, the
mineral fiber insulation batt can be made with a lower
amount of organic binder material than would otherwise be
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the case. Preferably, the amount of binder material is
within the range of from about 1 to about 7 percent by
weight of the unfaced batt. Most preferably, the binder
comprises between 1 and 4.6 percent by weight of the
unfaced batt. Such binders are well known to those
skilled in the art.
- One attribute of the facing material is that it
must be sufficiently slippery to enable the batt to be
pushed or slid into place on top of the existing attic
insulation material. Preferably, the coefficient of
kinetic friction of the faced batt is less than 1.0, when
the faced batt is pulled or dragged across a surface of an
unface~ 71ass fiber batt having a density of about 8.01-
12.81 ~ M3 (0.5 to about 0.8 pounds per cubic foot).
ASTM test D 2534-88 is a standard test method for
determining the coefficient of kinetic friction for wax
coatings. A test dynamically similar to D 2534-88 was
used to determine the coefficient of kinetic friction of
various facing materials suitable for use with mineral
fiber insulation. A reference batt of R-13 glass fiber
insulation was construc$ ~ ~ The reference batt has a
density of about 11.21 ~ (0.7 pounds per cubic foot)
- and measures 3.048 meters by 3.048 meters tone foot by one
foot) by about 9.2 cm (3-5/8 inches). The reference batt
was faced on the top side and unfaced on the bottom. The
batt was dragged at a speed of 50.8 cm (20 inches) per
minute across the various surfaces to be tested in
accordance with the general principles of ASTM D 2534-88,
and the coefficient of kinetic friction was determined by
measuring the amount of frictional resistance encountered.
The apparatus used is shown in Fig. ~ in which
reference batt 24 having facing 26 is pulled across the
testing surface 28. The reference batt was pulled by
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means of wire 30, which after being turned upwardly around
roller 32, was connected to a force measuring device. Any
device suitable for measuring the load on the wire, such
as a force transducer or Instron load cell 34, could be
used. The coefficient of kinetic frlction is the
measurement of the frictional force between the bottom
surface of the reference batt and the top surface of the
testing surface or facing material 28 to be tested.
EXAMPLE
The reference batt was dragged across five
different materials according to the test procedure
outlined above, with the following results.
Sample~O ~ 1O-6 Coefficient of Friction
Unperforated 4.0~ 6 meters
(0.4 mil) high density,
high molecular weight
PlYethYl~e~e~1o-G 0.826
Perforated ~q~ meters
(0.4 mil) high density,
: 20 high molecular weight
polyethylene 0.735
Kraft paper 0.186
AC plywood 2.5
Unfaced glass fiber batt 7.73
25 The above data show that the faced batt has a small
fraction of the friction exhibited by the action of
sliding one unfaced batt across the other. Preferably,
the coefficient of kinetic friction is within the range of
from about 0.7 to about 0.9, and most preferably it is
anything less than or equal to 1Ø
The fact that the side surfaces of the batt are
highly porous not only enables rapid compression by
allowing the escape of air during compression, but also
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facilitates the recovery of the product after the product
is unpac~aged in its place of intended use. ~ ~ ~ly,
the batt is capable of recovering to a predetermined
thickness after release from compression to one-fourth of
that predetermined thickness. For example, if the desired
nominal thickness of an R-19 glass fiber insulation batt
is 15.24 cm (6 inches), the batt can be compressed to a
thickness of 3.8 cm (1.5 inches), and upon release from
the packaging material, the batt wil~ self-recover to the
thickness of 15.24 cm (6 inches). Most preferably, the
batt is capable of recovering to a predetermined thickness
after release from compression to one-sixth of that
predetermined thickness.
It uill bo ~vidont fro~ ths forq1oin~ t~ iou~
~dific~tiona 6-n ~ m-~? t~ t~ nt; ~n 5~h,
ho-~v~rr -~o c~n~i~o.ro1 -e bo;~ t;'~;~ th~ -CO~O of h~
t ' i~n~ion
I~DUSTRI~' AP~LI~I'TTY
The mineral fiber insulation batt of the invention
can be used for additional insulation in the attic space
of a residential dwelling which has already been
- insulated.
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